Walton T. Roth
Professor of Psychiatry & Behavioral Sciences, Emeritus
Psychiatry and Behavioral Sciences
Current Research and Scholarly Interests
Laboratory and ambulatory recording of physiological, responses to stressors in anxious and phobic patients.
Clinical Trials
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Breathing Regulation Training for Individuals With Panic Disorder
Not Recruiting
This study will compare two different breathing regulation techniques to determine which is more effective in reducing the rate of panic attacks in people with panic disorder.
Stanford is currently not accepting patients for this trial.
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Respiratory Dysregulation and Breathing Training in Anxious Outpatients
Not Recruiting
This study will explore respiratory dysregulation in anxious outpatients and examine the effect of breathing training with biofeedback for those anxious patients.
Stanford is currently not accepting patients for this trial.
All Publications
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Randomized Clinical Trial of Capnometry-Assisted Respiratory Training in Veterans With Posttraumatic Stress Disorder Hyperarousal
PSYCHOLOGICAL TRAUMA-THEORY RESEARCH PRACTICE AND POLICY
2022; 14 (5): 883-893
Abstract
To investigate whether capnometry-assisted antihyperventilation respiratory training, successful in treating panic, and sleep hygiene instructions would reduce posttraumatic stress disorder (PTSD) hyperarousal symptoms in U.S. military veterans.We conducted a parallel, nonblinded clinical trial and randomized 80 veterans with PTSD hyperarousal into treatment or wait list. Primary treatment outcomes from baseline to 1st follow-up were analyzed using mixed modeling. Baseline physiological measures were compared between the PTSD hyperarousal group and a no-PTSD group (n = 68).Baseline respiration rate but not partial-pressure of end-tidal carbon dioxide (PCO₂) was higher in the PTSD hyperarousal group than in the no-PTSD group during 3 min of quiet sitting, indicating no difference in baseline hyperventilation. There was no significant effect of the intervention on PTSD hyperarousal symptoms or hyperventilation compared to wait list, but treatment did lower respiratory rate.This intervention did not reduce PTSD hyperarousal symptoms, perhaps due to differences between underlying mechanisms of PTSD hyperarousal and panic disorder or to differences between veteran and civilian populations. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
View details for DOI 10.1037/tra0000525
View details for Web of Science ID 000814350400023
View details for PubMedID 31804108
View details for PubMedCentralID PMC7272253
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Habituation or Normalization? Experiential and Respiratory Recovery From Voluntary Hyperventilation in Treated Versus Untreated Patients With Panic Disorder.
Behavior therapy
2021; 52 (1): 124–35
Abstract
Psychophysiological theories postulate respiratory dysregulation as a mechanism contributing to panic disorder (PD). Additionally, symptomatic and respiratory recovery from voluntary hyperventilation (HVT-recovery) have been shown to lag in PD and it is unclear if HVT-recovery normalizes with treatment. Thirty-seven panic disorder patients were randomized to hypoventilation therapy (TX, n = 20) or waitlist control (WL, n = 17) (Meuret et al., 2008). In a secondary analysis, their HVT-recovery was analyzed at pre- and post-TX/WL, compared to 29 healthy controls (HC). HVT included three phases: 5-min baseline, 3-min hyperventilation, and 8-min recovery. HVT-elicited symptom severity and anxiety were rated following each phase, and end-tidal PCO2 and respiratory rate (RR) were recorded throughout. Treatment, compared to WL, was highly effective in reducing PD pathology (d=2.21, Meuret et al., 2008). At pre-TX/WL, PD demonstrated delayed HVT-recovery PCO2 and higher RR. Treated patients demonstrated normalization of HVT-recovery for PCO2 and RR; however, improvements of HVT-recovery for symptom severity and anxiety did not differ between TX and WL. Results replicate pretreatment HVT respiratory recovery abnormalities in PD and further demonstrate normalization, comparable to HC, following successful treatment. The results provide support for respiratory dysregulation as a feature of PD and demonstrate the utility of HVT respiratory recovery as treatment outcome measure for respiration-based PD therapy.
View details for DOI 10.1016/j.beth.2020.03.003
View details for PubMedID 33483110
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MMR Vaccination: A Potential Strategy to Reduce Severity and Mortality of COVID-19 Illness.
The American journal of medicine
2020
View details for DOI 10.1016/j.amjmed.2020.10.003
View details for PubMedID 33198951
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Supplementing sleep actigraphy with button pressing while awake
PLOS ONE
2020; 15 (6)
View details for DOI 10.1371/journal.pone.0234060.r004
View details for Web of Science ID 000543273200069
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Supplementing sleep actigraphy with button pressing while awake.
PloS one
2020; 15 (6): e0234060
Abstract
Wrist-worn sleep actigraphs are limited for evaluating sleep, especially in sleepers who lie awake in bed without moving for extended periods. Sleep logs depend on the accuracy of perceiving and remembering times of being awake. Here we evaluated pressing an event-marker button while lying awake under two conditions: self-initiated pressing every 5 to 10 minutes or pressing when signaled every 5 minutes by a vibration pulse from a wristband. We evaluated the two conditions for acceptability and their concordance with actigraphically scored sleep.Twenty-nine adults wore actigraphs on six nights. On nights 1 and 4, they pressed the marker to a vibration signal, and on nights 2 and 5, they self-initiated presses without any signal. On nights 3 and 6, they were told not to press the marker. Every morning they filled out a sleep log about how they had slept.The vibration band was unacceptable to 42% of the participants, who judged it too disturbing to their sleep. Self-initiated pressing was acceptable to all, although it reduced log reported sleep depth compared to a no pressing condition. Estimations of sleep onset latency were considerably longer by button pressing than by actigraphy. Agreement of epoch-by-epoch sleep scoring by actigraphy and by button pressing was poor (kappa = 0.23) for self-initiated pressing and moderate (kappa = 0.46) for pressing in response to a vibration.Self-initiated button pressing to indicate being awake while lying in bed is acceptable to many, interferes little with sleep, and adds substantially to the information given by actigraphy.
View details for DOI 10.1371/journal.pone.0234060
View details for PubMedID 32555652
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Effects of psychosocial and physical stress on lactate and anxiety levels.
Stress (Amsterdam, Netherlands)
2019: 1–6
Abstract
Both intense physical activity and potent psychosocial stressors increase blood lactate. Raising lactate levels by infusing the chemical can have an anxiogenic effect. Here, we compare the relationship between changes in lactate and anxiety levels resulting from two standardized stressors. We investigated the effects of the Multiple Wingate All-Out Performance Test (WG), a strong physical stressor, and the Trier Social Stress Test (TSST), a well-documented psychosocial stressor, in 32 healthy young men using a crossover design. Before and after each stressor, venous blood was analyzed for lactate levels and the State-Trait-Anxiety Inventory (STAI) was given. Both stressors raised both lactate and anxiety significantly above their baseline levels. While the rise in lactate was much higher for the WG than for the TSST, the rises in anxiety were nearly equal. Individual fitness did not influence the results for lactate or anxiety. No significant relation between lactate and anxiety changes were found. Thus, our results as well as the literature suggest that lactate is an important variable for understanding the impact of sport participation.
View details for PubMedID 31062999
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Effects of psychosocial and physical stress on lactate and anxiety levels
STRESS-THE INTERNATIONAL JOURNAL ON THE BIOLOGY OF STRESS
2019
View details for DOI 10.1080/10253890.2019.1610743
View details for Web of Science ID 000471421400001
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Assessing sleep quality using self-report and actigraphy in PTSD
JOURNAL OF SLEEP RESEARCH
2018; 27 (3): e12632
Abstract
Sleep disturbance is commonly reported by participants with post-traumatic stress disorder, but objective evidence of poor sleep is often absent. Here we compared self-report and actigraphic evaluations of sleep between veterans with post-traumatic stress disorder and controls. Participants reported their sleep retrospectively for the month before the recording night and on the recording night. On the recording night, they wore an Actiwatch-64 and were instructed to press the marker button upon getting into bed, each time they awoke, and at their final awakening. The post-traumatic stress disorder group reported much worse sleep than controls on the Pittsburgh Sleep Quality Index for the previous month and somewhat poorer sleep on the recording night. However, on the recording night, neither diary nor actigraphic measures of number of awakenings, total time in bed, nor time lying awake after sleep onset differed between participants with and without post-traumatic stress disorder. Diary-reported number of awakenings was fewer than actigraphically captured awakenings. These results suggest a memory bias towards remembering worse sleep on the nights before the recording night.
View details for PubMedID 29171107
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Hypoventilation Therapy Alleviates Panic by Repeated Induction of Dyspnea.
Biological psychiatry. Cognitive neuroscience and neuroimaging
2018; 3 (6): 539-545
Abstract
Previous research has shown that hypoventilation therapy reduces panic symptoms in part by increasing basal partial pressure of carbon dioxide (PCO2) levels. We tested an additional pathway by which hypoventilation therapy could exert its therapeutic effects: through repeated interoceptive exposure to sensations of dyspnea.A total of 35 patients with panic disorder were trained to perform exercises to raise their end-tidal PCO2 levels using a portable capnometry device. Anxiety, dyspnea, end-tidal PCO2, and respiratory rate were assessed during each exercise across 4 weeks of training. Mixed-model analysis examined whether within-exercise levels of dyspnea were predictive of reduction of panicogenic cognitions.As expected, within-exercise anxiety and respiratory rate decreased over time. Unexpectedly, PCO2 dropped significantly from the beginning to the end of exercise, with these drops becoming progressively smaller across weeks. Dyspnea increased and remained consistently above basal levels across weeks. As hypothesized, greater dyspnea was related to significantly lower panicogenic cognitions over time even after controlling for anxiety and PCO2. Additional exploratory analyses showed that within-exercise increases in dyspnea were related to within-exercise increases in anxiety but were not related to within-exercise increases in PCO2.In support of the interoceptive exposure model, we found that greater dyspnea during hypoventilation exercises resulted in lower panicogenic cognitions even after the effect of PCO2 was taken into account. The findings offer an additional important target in panic treatment.
View details for DOI 10.1016/j.bpsc.2018.01.010
View details for PubMedID 29573981
View details for PubMedCentralID PMC6019126
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Motivation to Participate in PTSD Research.
JAMA
2018; 319 (23): 2439–40
View details for PubMedID 29922819
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Effects of therapeutic relationship, expectancy, and credibility in breathing therapies for anxiety
BULLETIN OF THE MENNINGER CLINIC
2015; 79 (2): 116-130
Abstract
The authors investigated the effects of the quality of the therapeutic alliance, expectancy of improvement, and credibility of treatment on the outcome of two breathing therapies for anxiety and panic. Data were collected during a randomized clinical trial evaluating the efficacy of two theoretically opposing, end-tidal pCO2 feedback-assisted breathing therapies for patients experiencing anxiety attacks. In this study, five weekly individual breathing therapy sessions were administered for the patients who were experiencing anxiety attacks as symptoms of various anxiety disorders. The outcome of this trial indicated that regardless of the opposing breathing instructions (raise or lower pCO2) used in the two breathing therapies, patients in both treatment groups improved equally after treatment. Nonspecific factors rather than the different directions of pCO2 changes could have played a role in the improvement. Regression analyses showed that for both therapies patient-rated therapeutic alliance was predictive of improvement at the 1-month follow-up, and that patient-rated confidence that the therapy would produce improvement, an aspect of its credibility, accounted for almost half of the variance in improvement at the 6-month follow-up. Thus, two factors usually considered nonspecific were identified to be potent predictors of treatment outcome.
View details for Web of Science ID 000355695000002
View details for PubMedID 26035087
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Autonomic Arousal During Actigraphically Estimated Waking and Sleep in Male Veterans With PTSD
JOURNAL OF TRAUMATIC STRESS
2014; 27 (5): 610-617
Abstract
Physiological hyperarousal is manifested acutely by increased heart rate, decreased respiratory sinus arrhythmia, and increased skin conductance level and variability. Yet it is uncertain to what extent such activation occurs with the symptomatic hyperarousal of posttraumatic stress disorder (PTSD). We compared 56 male veterans with current PTSD to 54 males who never had PTSD. Subjects wore ambulatory devices that recorded electrocardiograms, finger skin conductance, and wrist movement while in their normal environments. Wrist movement was monitored to estimate sleep and waking periods. Heart rate, but not the other variables, was elevated in subjects with PTSD equally during waking and during actigraphic sleep (effect sizes, Cohen's d, ranged from 0.63 to 0.89). The length of the sleep periods and estimated sleep fragmentation did not differ between groups. Group heart rate differences could not be explained by differences in body activity, PTSD hyperarousal symptom scores, depression, physical fitness, or antidepressant use.
View details for DOI 10.1002/jts.21947
View details for Web of Science ID 000343928000014
View details for PubMedID 25322890
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Psychiatry on Trial The Norway 2011 Massacre
JOURNAL OF NERVOUS AND MENTAL DISEASE
2014; 202 (3): 181-185
Abstract
On July 22, 2011, Anders Breivik, a Norwegian citizen, detonated a fertilizer bomb near government buildings in Oslo, killing eight people, and then proceeded to a nearby island where the Labor Party was holding a youth camp. There, he killed 69 people before being arrested. Just before these events, he posted a "compendium" on the Web explaining his actions and encouraging others to do likewise. Much of the ensuing media coverage and trial focused on whether he was sane and whether he had a psychiatric diagnosis. One team of court-appointed psychiatrists found him to be psychotic with a diagnosis of paranoid schizophrenia and legally insane. A second team found him neither psychotic nor schizophrenic and, thus, legally sane. Their contrary opinions were not reconciled by observing his behavior in court. We discuss why experienced psychiatrists reached such fundamentally opposing diagnostic conclusions about a "home-grown" terrorist holding extreme political views.
View details for DOI 10.1097/NMD.0000000000000109
View details for Web of Science ID 000333453300001
View details for PubMedID 24566502
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Experiential, autonomic, and respiratory correlates of CO2 reactivity in individuals with high and low anxiety sensitivity
PSYCHIATRY RESEARCH
2013; 209 (3): 566-573
Abstract
Psychometric studies indicate that anxiety sensitivity (AS) is a risk factor for anxiety disorders such as panic disorder (PD). To better understand the psychophysiological basis of AS and its relation to clinical anxiety, we examined whether high-AS individuals show similarly elevated reactivity to inhalations of carbon dioxide (CO2) as previously reported for PD and social phobia in this task. Healthy individuals with high and low AS were exposed to eight standardized inhalations of 20% CO2-enriched air, preceded and followed by inhalations of room air. Anxiety and dyspnea, in addition to autonomic and respiratory responses were measured every 15 s. Throughout the task, high AS participants showed a respiratory pattern of faster, shallower breathing and reduced inhalation of CO2 indicative of anticipatory or contextual anxiety. In addition, they showed elevated dyspnea responses to the second set of air inhalations accompanied by elevated heart rate, which could be due to sensitization or conditioning. Respiratory abnormalities seem to be common to high AS individuals and PD patients when considering previous findings with this task. Similarly, sensitization or conditioning of anxious and dyspneic symptoms might be common to high AS and clinical anxiety. Respiratory conditionability deserves greater attention in anxiety disorder research.
View details for DOI 10.1016/j.psychres.2013.02.010
View details for Web of Science ID 000326766300050
View details for PubMedID 23489596
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Worried sleep: 24-h monitoring in high and low worriers
BIOLOGICAL PSYCHOLOGY
2013; 94 (1): 61-70
Abstract
BACKGROUND: Commonly used trait measures might not accurately capture the relationship between worry and sleep difficulties in real life. METHODS: In a 24-h ambulatory monitoring study, high and low trait worriers maintained a log of worry and sleep characteristics while actigraphy, heart rates (HR), skin conductance (SC), and ambient temperature were recorded. RESULTS: Worrying in bed on the night of the recording was associated with longer self-reported and actigraphic nocturnal awakenings, lower actigraphic sleep efficiency, higher HR, lower HR variability, elevated SC level, and more non-specific SC fluctuations compared to not worrying in bed. High trait worriers had higher HR during waking and sleep, and reported shorter total sleep time and poorer sleep quality. CONCLUSIONS: While trait worry is mainly associated with subjective sleep difficulties, worrying in bed impairs sleep according to both subjective and objective sleep parameters, including heightened sympathetic and reduced parasympathetic activation.
View details for DOI 10.1016/j.biopsycho.2013.04.009
View details for Web of Science ID 000323480000007
View details for PubMedID 23643927
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Airway constriction in asthma during sustained emotional stimulation with films
BIOLOGICAL PSYCHOLOGY
2012; 91 (1): 8-16
Abstract
Individuals with asthma have been shown to respond to unpleasant stimuli with bronchoconstriction, but little is known about the time course of responding during sustained emotional stimulation and whether it varies with patients' experience.To examine the time course of oscillatory resistance (R(os)) during emotionally evocative films in 15 asthma patients and 14 healthy controls.Participants viewed unpleasant, surgery, and neutral films, each ranging 3-5min in duration. R(os) and the respiratory pattern (respiration rate, tidal volume, minute ventilation) were monitored continuously. Following each film, participants rated their affective response and symptoms. The time course of R(os) during films was explored using multilevel modeling.Compared to neutral film sequences, unpleasant films (including those with surgery scenes) elicited a uniform pattern of initial increases in R(os) with peaks within the first 1-2min, followed by a gradual decline. Increases were more pronounced in asthma and during surgery films. Including additional respiratory parameters as time-varying covariates did not affect the temporal course of R(os) change. The rate of decline in R(os) (after the initial increase) was less in participants who experienced greater arousal and in patients who reported more shortness of breath. Patients more susceptible to psychological triggers in daily life showed slower rates of decline in R(os).The temporal course of bronchoconstriction to unpleasant stimulation is highly uniform in asthma, with strong constriction in early stages of stimulation. More sustained constriction in emotion-induced asthma could be a risk factor for developing asthma exacerbation in daily life.
View details for DOI 10.1016/j.biopsycho.2012.03.014
View details for Web of Science ID 000307693100002
View details for PubMedID 22490762
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Opposing Breathing Therapies for Panic Disorder: A Randomized Controlled Trial of Lowering vs Raising End-Tidal PCO2
JOURNAL OF CLINICAL PSYCHIATRY
2012; 73 (7): 931-939
Abstract
Teaching anxious clients to stop hyperventilating is a popular therapeutic intervention for panic. However, evidence for the theory behind this approach is tenuous, and this theory is contradicted by an opposing theory of panic, the false-suffocation alarm theory, which can be interpreted to imply that the opposite would be helpful.To test these opposing approaches by investigating whether either, both, or neither of the 2 breathing therapies is effective in treating patients with panic disorder.We randomly assigned 74 consecutive patients with DSM-IV-diagnosed panic disorder (mean age at onset = 33.0 years) to 1 of 3 groups in the setting of an academic research clinic. One group was trained to raise its end-tidal P(CO₂) (partial pressure of carbon dioxide, mm Hg) to counteract hyperventilation by using feedback from a hand-held capnometer, a second group was trained to lower its end-tidal P(CO₂) in the same way, and a third group received 1 of these treatments after a delay (wait-list). We assessed patients physiologically and psychologically before treatment began and at 1 and 6 months after treatment. The study was conducted from September 2005 through November 2009.Using the Panic Disorder Severity Scale as a primary outcome measure, we found that both breathing training methods effectively reduced the severity of panic disorder 1 month after treatment and that treatment effects were maintained at 6-month follow-up (effect sizes at 1-month follow-up were 1.34 for the raise-CO(2) group and 1.53 for the lower-CO(2) group; P < .01). Physiologic measurements of respiration at follow-up showed that patients had learned to alter their P(CO₂) levels and respiration rates as they had been taught in therapy.Clinical improvement must have depended on elements common to both breathing therapies rather than on the effect of the therapies themselves on CO(2) levels. These elements may have been changed beliefs and expectancies, exposure to ominous bodily sensations, and attention to regular and slow breathing.ClinicalTrials.gov identifier: NCT00183521.
View details for DOI 10.4088/JCP.11m07068
View details for Web of Science ID 000315000200004
View details for PubMedID 22901344
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Separation anxiety disorder in children: disorder-specific responses to experimental separation from the mother
JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY
2012; 53 (2): 178-187
Abstract
Separation anxiety disorder (SAD) is one of the most common anxiety disorders in childhood and is predictive of adult anxiety disorders, especially panic disorder. However, the disorder has seldom been studied and the attempt to distinguish SAD from other anxiety disorders with regard to psychophysiology has not been made. We expected exaggerated anxiety as well as sympathetic and respiratory reactivity in SAD during separation from the mother.Participants were 49 children with a principal diagnosis of SAD, 21 clinical controls (CC) with a principal diagnosis of anxiety disorder other than SAD, and 39 healthy controls (HC) not meeting criteria for any current diagnosis. Analyses of covariance controlling for age were used to assess sympathetic and parasympathetic activation (preejection period and respiratory sinus arrhythmia) as well as cardiovascular (heart rate, mean arterial pressure, total peripheral resistance), respiratory (total breath time, minute ventilation, tidal volume, end-tidal CO(2) , respiratory variability), electrodermal, and self-report (anxiety, cognitions, symptoms) variables during baseline, 4-min separation from, and reunion with the mother.Children with a diagnosis of SAD were characterized by elevated self-reported anxiety responses to separation and increased sympathetic reactivity compared with CC and HC groups. The SAD group also displayed greater vagal withdrawal and higher reactivity in multiple cardiovascular, respiratory, and electrodermal measures compared with the HC group, while corresponding responses were less in the CC group and not significantly different from the other groups.Separation from the mother elicits greater autonomic, respiratory, and experiential responses in children with SAD. Our findings based on brief experimental separation demonstrate differential subjective and physiological manifestations of specific anxiety diagnoses, thus supporting the validity of the diagnostic category of SAD.
View details for DOI 10.1111/j.1469-7610.2011.02465.x
View details for Web of Science ID 000299042900011
View details for PubMedID 21923807
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SPR Award, 2010. For distinguished contributions to psychophysiology: Judith M. Ford.
Psychophysiology
2012; 49 (2): 151-3
View details for DOI 10.1111/j.1469-8986.2011.01292.x
View details for PubMedID 22091850
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Do Unexpected Panic Attacks Occur Spontaneously?
BIOLOGICAL PSYCHIATRY
2011; 70 (10): 985-991
Abstract
Spontaneous or unexpected panic attacks, per definition, occur "out of the blue," in the absence of cues or triggers. Accordingly, physiological arousal or instability should occur at the onset of, or during, the attack, but not preceding it. To test this hypothesis, we examined if points of significant autonomic changes preceded the onset of spontaneous panic attacks.Forty-three panic disorder patients underwent repeated 24-hour ambulatory monitoring. Thirteen natural panic attacks were recorded during 1960 hours of monitoring. Minute-by-minute epochs beginning 60 minutes before and continuing to 10 minutes after the onset of individual attacks were examined for respiration, heart rate, and skin conductance level. Measures were controlled for physical activity and vocalization and compared with time matched control periods within the same person.Significant patterns of instability across a number of autonomic and respiratory variables were detected as early as 47 minutes before panic onset. The final minutes before onset were dominated by respiratory changes, with significant decreases in tidal volume followed by abrupt carbon dioxide partial pressure increases. Panic attack onset was characterized by heart rate and tidal volume increases and a drop in carbon dioxide partial pressure. Symptom report was consistent with these changes. Skin conductance levels were generally elevated in the hour before, and during, the attacks. Changes in the matched control periods were largely absent.Significant autonomic irregularities preceded the onset of attacks that were reported as abrupt and unexpected. The findings invite reconsideration of the current diagnostic distinction between uncued and cued panic attacks.
View details for DOI 10.1016/j.biopsych.2011.05.027
View details for Web of Science ID 000296493800013
View details for PubMedID 21783179
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An affective computing approach to physiological emotion specificity: Toward subject-independent and stimulus-independent classification of film-induced emotions
PSYCHOPHYSIOLOGY
2011; 48 (7): 908-922
Abstract
The hypothesis of physiological emotion specificity has been tested using pattern classification analysis (PCA). To address limitations of prior research using PCA, we studied effects of feature selection (sequential forward selection, sequential backward selection), classifier type (linear and quadratic discriminant analysis, neural networks, k-nearest neighbors method), and cross-validation method (subject- and stimulus-(in)dependence). Analyses were run on a data set of 34 participants watching two sets of three 10-min film clips (fearful, sad, neutral) while autonomic, respiratory, and facial muscle activity were assessed. Results demonstrate that the three states can be classified with high accuracy by most classifiers, with the sparsest model having only five features, even for the most difficult task of identifying the emotion of an unknown subject in an unknown situation (77.5%). Implications for choosing PCA parameters are discussed.
View details for DOI 10.1111/j.1469-8986.2010.01170.x
View details for Web of Science ID 000291255500004
View details for PubMedID 21261632
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Effects of Breathing Training on Voluntary Hypo- and Hyperventilation in Patients with Panic Disorder and Episodic Anxiety
APPLIED PSYCHOPHYSIOLOGY AND BIOFEEDBACK
2011; 36 (2): 81-91
Abstract
Anxiety disorders are associated with respiratory abnormalities. Breathing training (BT) aimed at reversing these abnormalities may also alter the anxiogenic effects of biological challenges. Forty-five Panic Disorder (PD) patients, 39 Episodic Anxiety patients, and 20 non-anxious controls underwent voluntary hypoventilation and hyperventilation tests twice while psychophysiological measures were recorded. Patients were randomized to one of two BT therapies (Lowering vs. Raising pCO(2)) or to a waitlist. Before treatment panic patients had higher respiration rates and more tidal volume instability and sighing at rest than did non-anxious controls. After the Lowering therapy, patients had lower pCO(2) during testing. However, neither reactivity nor recovery to either test differed between patients and controls, or were affected by treatment. Although the two treatments had their intended opposite effects on baseline pCO(2), other physiological measures were not affected. We conclude that baseline respiratory abnormalities are somewhat specific to PD, but that previously reported greater reactivity and slower recovery to respiratory challenges may be absent.
View details for DOI 10.1007/s10484-011-9150-5
View details for Web of Science ID 000290026100003
View details for PubMedID 21373936
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Methodological considerations in ambulatory skin conductance monitoring
INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY
2011; 80 (2): 87-95
Abstract
Little is known how much skin conductance (SC) recordings from the fingers are affected by factors such as electrode site deterioration, ambient temperature (TMP), or physical activity (ACT), or by age, sex, race, or body mass index. We recorded SC, TMP, and ACT in 48 healthy control subjects for a 24-hour period, and calculated SC level (SCL), its standard deviation, the coefficient of SC variation, and frequency and amplitude of non-specific SC fluctuations. One method of assessing electrode site deterioration showed an average decline of 20%, while a second method found no significant change. All SC measures were higher during waking than sleep. Other factors influenced different measures in different ways. Thus, 24-hour SC recording outside the laboratory is feasible, but some measures need to be corrected for the influence of confounding variables.
View details for DOI 10.1016/j.ijpsycho.2011.02.002
View details for Web of Science ID 000290648300001
View details for PubMedID 21320551
View details for PubMedCentralID PMC3075336
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Affective modulation of the acoustic startle: Does sadness engage the defensive system?
BIOLOGICAL PSYCHOLOGY
2011; 87 (1): 161-163
Abstract
It has been suggested that high arousal negative affective states, but not low arousal negative affective states, potentiate the startle response. Because sadness has generally been studied as a low arousal emotion, it remains unclear whether high arousal sadness would produce startle potentiation to a similar degree as high arousal fear. To address this issue, 32 participants viewed two sets of 10-min film clips selected to induce two affective states of high subjective arousal (fear, sadness) and a neutral state of low subjective arousal, while the eyeblink startle response associated with brief noise bursts was assessed using orbicularis oculi EMG. Larger blink magnitude was found for fearful than for sad or neutral clips. Implications for conceptualizing sadness are discussed.
View details for DOI 10.1016/j.biopsycho.2011.02.008
View details for Web of Science ID 000290195100020
View details for PubMedID 21352887
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Cardio-respiratory instabilities precede the onset of naturally occurring panic attacks
17th Annual Meeting of the International-Society-for-the-Advancement-of-Respiratory-Psychophysiology
ELSEVIER SCIENCE BV. 2011: 173–74
View details for Web of Science ID 000290195100039
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Airway response to emotion- and disease-specific films in asthma, blood phobia, and health
PSYCHOPHYSIOLOGY
2011; 48 (1): 121-135
Abstract
Earlier research found autonomic and airway reactivity in asthma patients when they were exposed to blood-injection-injury (BII) stimuli. We studied oscillatory resistance (R(os)) in asthma and BII phobia during emotional and disease-relevant films and examined whether muscle tension counteracts emotion-induced airway constriction. Fifteen asthma patients, 12 BII phobia patients, and 14 healthy controls viewed one set of negative, positive, neutral, BII-related, and asthma-related films with leg muscle tension and a second set without. R(os), ventilation, cardiovascular activity, and skin conductance were measured continuously. R(os) was higher during emotional compared to neutral films, particularly during BII material, and responses increased from healthy over asthmatic to BII phobia participants. Leg muscle tension did not abolish R(os) increases. Thus, the airways are particularly responsive to BII-relevant stimuli, which could become risk factors for asthma patients.
View details for DOI 10.1111/j.1469-8986.2010.01044.x
View details for Web of Science ID 000285155600014
View details for PubMedID 20573055
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Twenty-four hour skin conductance in panic disorder
JOURNAL OF PSYCHIATRIC RESEARCH
2010; 44 (16): 1137-1147
Abstract
Skin conductance, physical activity, ambient temperature and mood were recorded for 24 h in 22 panic disorder (PD) patients and 29 healthy controls. During the day, subjects performed standardized relaxation tests (ARTs). We hypothesized that tonically elevated anticipatory anxiety in PD during waking and sleeping would appear as elevated skin conductance level (SCL) and greater skin conductance (SC) variability. Mean SCL was higher during both usual waking activities and sleeping in PD, but not during the ARTs. Group SC variability differences did not reach significance, perhaps because of variance unrelated to anxiety. Analyses indicated that in the PD group, antidepressant medication reduced mean SCL whereas state anxiety had the opposite effect during the day. Depressive symptoms reported during the day were related to elevated mean SCL on the night of the recording. The rate and extent of SCL deactivation over the night was equal in the two groups. However, PD patients had more frequent interruptions of deactivation that could have arisen from conditioned arousal in response to threat cues during sleep.
View details for DOI 10.1016/j.jpsychires.2010.04.012
View details for Web of Science ID 000285952000003
View details for PubMedID 20537349
View details for PubMedCentralID PMC2937198
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Temporal stability and coherence of anxiety, dyspnea, and physiological variables in panic disorder
BIOLOGICAL PSYCHOLOGY
2010; 85 (2): 226-232
Abstract
Twenty-five panic disorder (PD) patients, 19 social phobics (SP), and 20 healthy controls (HC) sat quietly for 15 min, rating their anxiety and dyspnea every 30s while respiratory, cardiovascular, and electrodermal responses were recorded. No panic attacks were reported. For self-reported anxiety and dyspnea, within-subject variability over time was higher in PD than in SP or HC. In PD within-subject correlations across 30-s epochs were significant for (a) self-reported anxiety versus dyspnea, end-tidal pCO2, minute volume, duty cycle, skin conductance level, and interbeat interval, and for (b) dyspnea versus end-tidal pCO2, minute volume, tidal volume, and inspiratory flow rate. Several positive or negative correlations were greater in PD than in other groups. Thus in PD, experienced anxiety and dyspnea are temporally unstable but are correlated with each other and with fluctuations in respiratory and autonomic variables, even in the absence of panic attacks.
View details for DOI 10.1016/j.biopsycho.2010.07.005
View details for Web of Science ID 000283002400006
View details for PubMedID 20637257
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Respiratory, autonomic, and experiential responses to repeated inhalations of 20% CO2 enriched air in panic disorder, social phobia, and healthy controls
BIOLOGICAL PSYCHOLOGY
2010; 84 (1): 104-111
Abstract
Inhalation of carbon dioxide (CO₂) enriched air triggers anxiety in panic disorder (PD) patients, which is often interpreted as a sign of biological vulnerability. However, most studies have not measured respiration in these tasks. We compared patients with PD (n=20) and social phobia (SP, n=19) to healthy controls (n=18) during eight inhalations of 20% CO₂, preceded and followed by two inhalations of room air, while continuously measuring subjective anxiety and dyspnea as well as autonomic and respiratory variables. PD patients showed increased reactivity and delayed recovery during CO₂ inhalations for most measures. Unlike both other groups, the PD group's tidal volume responses did not habituate across CO₂ inhalations. However, PD patients did not differ from SP patients on most other measures, supporting a continuum model of CO₂ sensitivity across anxiety disorders. Both patient groups showed continued reactivity during the last air inhalations, which is unlikely to be due to a biological sensitivity.
View details for DOI 10.1016/j.biopsycho.2010.01.002
View details for Web of Science ID 000278466200013
View details for PubMedID 20064582
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Psychophysiological Characteristics of Women Suffering from Stress-Related Fatigue
STRESS AND HEALTH
2010; 26 (2): 113-126
View details for DOI 10.1002/smi.1271
View details for Web of Science ID 000277351900003
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Change point analysis for longitudinal physiological data: Detection of cardio-respiratory changes preceding panic attacks
BIOLOGICAL PSYCHOLOGY
2010; 84 (1): 112-120
Abstract
Statistical methods for detecting changes in longitudinal time series of psychophysiological data are limited. ANOVA and mixed models are not designed to detect the existence, timing, or duration of unknown changes in such data. Change point (CP) analysis was developed to detect distinct changes in time series data. Preliminary reports using CP analysis for fMRI data are promising. Here, we illustrate the application of CP analysis for detecting discrete changes in ambulatory, peripheral physiological data leading up to naturally occurring panic attacks (PAs). The CP method was successful in detecting cardio-respiratory changes that preceded the onset of reported PAs. Furthermore, the changes were unique to the pre-PA period, and were not detected in matched non-PA control periods. The efficacy of our CP method was further validated by detecting patterns of change that were consistent with prominent respiratory theories of panic positing a relation between aberrant respiration and panic etiology.
View details for DOI 10.1016/j.biopsycho.2010.01.020
View details for Web of Science ID 000278466200014
View details for PubMedID 20144682
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DIVERSITY OF EFFECTIVE TREATMENTS OF PANIC ATTACKS: WHAT DO THEY HAVE IN COMMON?
DEPRESSION AND ANXIETY
2010; 27 (1): 5-11
Abstract
By comparing efficacious psychological therapies of different kinds, inferences about common effective treatment mechanisms can be made. We selected six therapies for review on the basis of the diversity of their theoretical rationales and evidence for superior efficacy: psychoanalytic psychotherapy, hypercapnic breathing training, hypocapnic breathing training, reprocessing with and without eye-movement desensitization, muscle relaxation, and cognitive behavior therapy. The likely common element of all these therapies is that they reduce the immediate expectancy of a panic attack, disrupting the vicious circle of fearing fear. Modifying expectation is usually regarded as a placebo mechanism in psychotherapy, but may be a specific treatment mechanism for panic. The fact that this is seldom the rationale communicated to the patient creates a moral dilemma: Is it ethical for therapists to mislead patients to help them? Pragmatic justification of a successful practice is a way out of this dilemma. Therapies should be evaluated that deal with expectations directly by promoting positive thinking or by fostering non-expectancy.
View details for DOI 10.1002/da.20601
View details for Web of Science ID 000273468300002
View details for PubMedID 20049938
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Does improving mood in depressed patients alter factors that may affect cardiovascular disease risk?
JOURNAL OF PSYCHIATRIC RESEARCH
2009; 43 (16): 1246-1252
Abstract
To determine if improvement in mood would ameliorate autonomic dysregulation, HPA dysfunction, typical risk factors and C-reactive protein in depressed patients with elevated cardiovascular disease risk (CVD), 48 depressed participants with elevated cardiovascular risk factors were randomized to a cognitive behavioral intervention (CBT) or a waiting list control (WLC) condition. Twenty non-depressed age and risk-matched controls were also recruited. Traditional risk factors (e.g., lipids, blood pressure) and C-reactive protein were assessed pre- and post-treatment six months later. Subjects also underwent a psychophysiological stress test while cardiovascular physiology was measured. Salivary cortisol was measured during the day and during the psychological stress test. At post-treatment, the CBT subjects were significantly less depressed than WLC subjects. There was no significant difference in change scores on any of the traditional risk factors or C-reactive protein, cortisol measures, or cardiovascular physiology, except for triglyceride levels and heart rate, which were significantly lower in treatment compared to control subjects. The normal controls exhibited no change in the variables measured during the same time. A significant improvement in mood may have little impact on most traditional or atypical risk factors, cortisol or cardiophysiology.
View details for DOI 10.1016/j.jpsychires.2009.05.006
View details for Web of Science ID 000272860300002
View details for PubMedID 19577757
View details for PubMedCentralID PMC2783820
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Changes in respiration mediate changes in fear of bodily sensations in panic disorder
JOURNAL OF PSYCHIATRIC RESEARCH
2009; 43 (6): 634-641
Abstract
The purpose of the study was to examine whether changes in pCO(2) mediate changes in fear of bodily sensation (as indexed by anxiety sensitivity) in a bio-behavioral treatment for panic disorder that targets changes in end-tidal pCO(2). Thirty-five panic patients underwent 4 weeks of capnometry-assisted breathing training targeting respiratory dysregulation. Longitudinal mediation analyses of the changes in fear of bodily symptoms over time demonstrated that pCO(2), but not respiration rate, was a partial mediator of the changes in anxiety sensitivity. Results were supported by cross lag panel analyses, which indicated that earlier pCO(2) levels predicted later levels of anxiety sensitivity, but not vice versa. PCO(2) changes also led to changes in respiration rate, questioning the importance of respiration rate in breathing training. The results provide little support for changes in fear of bodily sensations leading to changes in respiration, but rather suggest that breathing training targeting pCO(2) reduced fear of bodily sensations in panic disorder.
View details for DOI 10.1016/j.jpsychires.2008.08.003
View details for Web of Science ID 000264613200009
View details for PubMedID 18835608
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Changes in pCO(2), Symptoms, and Lung Function of Asthma Patients During Capnometry-assisted Breathing Training
APPLIED PSYCHOPHYSIOLOGY AND BIOFEEDBACK
2009; 34 (1): 1-6
Abstract
In a recent pilot study with asthma patients we demonstrated beneficial outcomes of a breathing training using capnometry biofeedback and paced breathing assistance to increase pCO(2) levels and reduce hyperventilation. Here we explored the time course changes in pCO(2), respiration rate, symptoms and lung function across treatment weeks, in order to determine how long training needs to continue. We analyzed in eight asthma patients whether gains in pCO(2) and reductions in respiration rate achieved in home exercises with paced breathing tapes followed a linear trend across the 4-week treatment period. We also explored the extent to which gains at home were manifest in weekly training sessions in the clinic, in terms of improvement in symptoms and spirometric lung function. The increases in pCO(2) and respiration rate were linear across treatment weeks for home exercises. Similar increases were seen for in-session measurements, together with gradual decreases in symptoms from week to week. Basal lung function remained stable throughout treatment. With our current protocol of paced breathing and capnometry-assisted biofeedback at least 4 weeks are needed to achieve a normalization of pCO(2) levels and reduction in symptoms in asthma patients.
View details for DOI 10.1007/s10484-008-9070-1
View details for Web of Science ID 000263523200001
View details for PubMedID 19048369
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End-tidal versus transcutaneous measurement of PCO2 during voluntary hypo- and hyperventilation
INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY
2009; 71 (2): 103-108
Abstract
Recent studies have shown that end-tidal PCO(2) is lower during anxiety and stress, and that changing PCO(2) by altering breathing is therapeutic in panic disorder. However, end-tidal estimation of arterial PCO(2) has drawbacks that might be avoided by the transcutaneous measurement method. Here we compare transcutaneous and end-tidal PCO(2) under different breathing conditions in order to evaluate these methods in terms of their comparability and usability. Healthy volunteers performed two hypoventilation (slow vs. paused breathing) and two hyperventilation tests (25 mm Hg at 18 vs. 30 breaths per minute). Three measurements of PCO(2) (two end-tidal and one transcutaneous device), tidal volume, and respiration rate were recorded. Before and after each test, subjects filled out a symptom questionnaire. The results show that PCO(2) estimated by the two methods was comparable except that for transcutaneous measurement registration of changes in PCO(2) was delayed and absolute levels were much higher. Both methods documented that paused breathing was effective for raising PCO(2), a presumed antidote for anxious hyperventilation. We conclude that since the two methods give comparable results choosing between them for specific applications is principally a matter of whether the time lag of the transcutaneous method is acceptable.
View details for DOI 10.1016/j.ijpsycho.2008.07.011
View details for Web of Science ID 000263623800003
View details for PubMedID 18706460
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Do blood phobia patients hyperventilate during exposure by breathing faster, deeper, or both?
Depression and anxiety
2009; 26 (2): E60-7
Abstract
Recently we found that patients with blood-injection-injury (BII) phobia tend to hyperventilate when exposed to feared stimuli. Hyperventilation results from increases in minute ventilation above levels required by metabolic demand and can result from increases in either frequency or depth of breathing, or a combination of both.In order to determine which of these factors contributed most to hyperventilation in BII phobia we analyzed breathing patterns of BII phobia patients (N=12) and non-anxious controls (N=14), recorded with respiratory inductance plethysmography. Participants viewed ten film clips of either an emotionally positive, negative, or neutral quality, as well as surgery and asthma-relevant clips. During five film clips (one from each category) they also tensed their leg muscles.Minute ventilation was markedly increased in blood phobia patients compared to other groups during surgery films. Also, tidal volume and irregularity of tidal volume showed strong increases, while respiration rate was not affected. Leg muscle tension increased ventilation in general but far below the extent brought about by hyperventilation in BII phobia. Patients who were breathing deeper during exposure reported stronger symptoms of dizziness, light-headedness and faintness. In general, patients showed a higher rate of spontaneous sighs throughout all film presentations, but not at baseline.Thus, hyperventilation in blood phobia is produced by excessively deep and irregular breathing and may contribute to fainting responses. Behavioral interventions for BII phobia could benefit from attention to this aspect of dysfunctional breathing.
View details for DOI 10.1002/da.20466
View details for PubMedID 19085969
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Circadian affective, cardiopulmonary, and cortisol variability in depressed and nondepressed individuals at risk for cardiovascular disease
JOURNAL OF PSYCHIATRIC RESEARCH
2008; 42 (9): 769-777
Abstract
Depression is a risk factor for cardiovascular disease (CVD) perhaps mediated by hypothalamic-pituitary-adrenal (HPA) axis or vagal dysregulation. We investigated circadian mood variation and HPA-axis and autonomic function in older (55 years) depressed and nondepressed volunteers at risk for CVD by assessing diurnal positive and negative affect (PA, NA), cortisol, and cardiopulmonary variables in 46 moderately depressed and 19 nondepressed volunteers with elevated CVD risk. Participants sat quietly for 5-min periods (10:00, 12:00, 14:00, 17:00, 19:00, and 21:00), and then completed an electronic diary assessing PA and NA. Traditional and respiration-controlled heart rate variability (HRV) variables were computed for these periods as an index of vagal activity. Salivary cortisols were collected at waking, waking+30min, 12:00, 17:00, and 21:00h. Cortisol peaked in the early morning after waking, and gradually declined over the day, but did not differ between groups. PA was lower and NA was higher in the depressed group throughout the day. HRV did not differ between groups. Negative emotions were inversely related to respiratory sinus arrhythmia in nondepressed participants. We conclude that moderately depressed patients do not show abnormal HPA-axis function. Diurnal PA and NA distinguish depressed from nondepressed individuals at risk for CVD, while measures of vagal regulation, even when controlled for physical activity and respiratory confounds, do not. Diurnal mood variations of older individuals at risk for CVD differ from those reported for other groups and daily fluctuations in NA are not related to cardiac autonomic control in depressed individuals.
View details for DOI 10.1016/j.jpsychires.2007.08.003
View details for Web of Science ID 000256651600009
View details for PubMedID 17884093
View details for PubMedCentralID PMC2478702
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Translational research for panic disorder
AMERICAN JOURNAL OF PSYCHIATRY
2008; 165 (7): 796-798
View details for DOI 10.1176/appi.ajp.2008.08040533
View details for Web of Science ID 000257320100004
View details for PubMedID 18593782
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Psychophysiological reactions to two levels of voluntary hyperventilation in panic disorder
JOURNAL OF ANXIETY DISORDERS
2008; 22 (5): 886-898
Abstract
Panic disorder (PD) patients usually react with more self-reported distress to voluntary hyperventilation (HV) than do comparison groups. Less consistently PD patients manifest physiological differences such as more irregular breathing and slower normalization of lowered end-tidal pCO(2) after HV. To test whether physiological differences before, during, or after HV would be more evident after more intense HV, we designed a study in which 16 PD patients and 16 non-anxious controls hyperventilated for 3 min to 25 mmHg, and another 19 PD patients and another 17 controls to 20 mmHg. Patients reacted to HV to 20 mmHg but not to 25 mmHg with more self-reported symptoms than controls. However, at neither HV intensity were previous findings of irregular breathing and slow normalization of pCO(2) replicated. In general, differences between patients and controls in response to HV were in the cognitive-language rather than in the physiological realm.
View details for DOI 10.1016/j.janxdis.2007.09.004
View details for Web of Science ID 000256189100013
View details for PubMedID 17950571
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A discrete or dimensional affective landscape? Evidence for emotion discreteness from a multiple-response-levels analysis of film-induced fear and sadness
PSYCHOLOGY PRESS. 2008: 203–
View details for Web of Science ID 000259264302315
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Feedback of end-tidal pCO(2) as a therapeutic approach for panic disorder
JOURNAL OF PSYCHIATRIC RESEARCH
2008; 42 (7): 560-568
Abstract
Given growing evidence that respiratory dysregulation is a central feature of panic disorder (PD) interventions for panic that specifically target respiratory functions could prove clinically useful and scientifically informative. We tested the effectiveness of a new, brief, capnometry-assisted breathing therapy (BRT) on clinical and respiratory measures in PD.Thirty-seven participants with PD with or without agoraphobia were randomly assigned to BRT or to a delayed-treatment control group. Clinical status, respiration rate, and end-tidal pCO(2) were assessed at baseline, post-treatment, 2-month and 12-month follow-up. Respiratory measures were also assessed during homework exercises using a portable capnometer as a feedback device.Significant improvements (in PD severity, agoraphobic avoidance, anxiety sensitivity, disability, and respiratory measures) were seen in treated, but not untreated patients, with moderate to large effect sizes. Improvements were maintained at follow-up. Treatment compliance was high for session attendance and homework exercises; dropouts were few.The data provide preliminary evidence that raising end-tidal pCO(2) by means of capnometry feedback is therapeutically beneficial for panic patients. Replication and extension will be needed to verify this new treatment's efficacy and determine its mechanisms.
View details for DOI 10.1016/j.jpsychires.2007.06.005
View details for Web of Science ID 000255424000007
View details for PubMedID 17681544
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The psychophysiology of generalized anxiety disorder: 2. Effects of applied relaxation
PSYCHOPHYSIOLOGY
2008; 45 (3): 377-388
Abstract
Muscle relaxation therapy assumes that generalized anxiety disorder (GAD) patients lack the ability to relax but can learn this in therapy. We tested this by randomizing 49 GAD patients to 12 weeks of Applied Relaxation (AR) or waiting. Before, during, and after treatment participants underwent relaxation tests. Before treatment, GAD patients were more worried than healthy controls (n=21) and had higher heart rates and lower end-tidal pCO2, but not higher muscle tension (A. Conrad, L. Isaac, & W.T. Roth, 2008). AR resulted in greater symptomatic improvement than waiting. However, 28% of the AR group dropped out of treatment and some patients relapsed at the 6-week follow-up. There was little evidence that AR participants learned to relax in therapy or that a reduction in anxiety was associated with a decrease in activation. We conclude that the clinical effects of AR in improving GAD symptoms are moderate at most and cannot be attributed to reducing muscle tension or autonomic activation.
View details for DOI 10.1111/j.1469-8986.2007.00644.x
View details for Web of Science ID 000254792100006
View details for PubMedID 18221441
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The psychophysiology of generalized anxiety disorder: 1. Pretreatment characteristics
PSYCHOPHYSIOLOGY
2008; 45 (3): 366-376
Abstract
Generalized anxiety disorder (GAD) patients have been reported to have more muscle tension than controls, which has provided a rationale for treating them with muscle relaxation therapies (MRT). We tested this rationale by comparing 49 GAD patients with 21 controls. Participants underwent 5-min relaxation tests, during which they either just sat quietly (QS) or sat quietly and tried to relax (R). GAD patients reported themselves to be more worried during the assessment than the controls, had higher heart rates and lower end-tidal pCO2, but not higher muscle tension as measured by multiple EMGs. QS and R did not differ on most psychological and physiological measures, indicating that intention to relax did not affect speed of relaxation. In the GAD group, self-reported anxiety was not associated with electromyographic or autonomic measures. We conclude that GAD is not necessarily characterized by chronic muscle tension, and that this rationale for MRT should be reconsidered.
View details for DOI 10.1111/j.1469-8986.2007.00601.x
View details for Web of Science ID 000254792100005
View details for PubMedID 18221449
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Sympathetic activation in broadly defined generalized anxiety disorder
JOURNAL OF PSYCHIATRIC RESEARCH
2008; 42 (3): 205-212
Abstract
The definition of generalized anxiety disorder (GAD) has been narrowed in successive editions of DSM by emphasizing intrusive worry and deemphasizing somatic symptoms of hyperarousal. We tried to determine the clinical characteristics of more broadly defined chronically anxious patients, and whether they would show physiological signs of sympathetic activation. A group whose chief complaint was frequent, unpleasant tension over at least the last six weeks for which they desired treatment, was compared with a group who described themselves as calm. Participants were assessed with structured interviews and questionnaires. Finger skin conductance, motor activity, and ambient temperature were measured for 24h. Results show that during waking and in bed at night, runs of continuous minute-by-minute skin conductance level (SCL) declines were skewed towards being shorter in the tense group than in the calm group. In addition, during waking, distributions of minute SCLs were skewed towards higher levels in the tense group, although overall mean SCL did not differ. Thus, the tense group showed a failure to periodically reduce sympathetic tone, presumably a corollary of failure to relax. We conclude that broader GAD criteria include a substantial number of chronically anxious and hyperaroused patients who do not fall within standard criteria. Such patients deserve attention by clinicians and researchers.
View details for DOI 10.1016/j.jpsychires.2006.12.003
View details for Web of Science ID 000253397900005
View details for PubMedID 17250853
View details for PubMedCentralID PMC2262283
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Cardiovascular, electrodermal, and respiratory response patterns to fear- and sadness-inducing films
12th Annual Meeting of the Society-for-Psychophysiological-Research
WILEY-BLACKWELL. 2007: 787–806
Abstract
Responses to fear- and sadness-inducing films were assessed using a broad range of cardiovascular (heart rate, T-wave amplitude, low- and high-frequency heart rate variability, stroke volume, preejection period, left-ventricular ejection time, Heather index, blood pressure, pulse amplitude and transit time, and finger temperature), electrodermal (level, response rate, and response amplitude), and respiratory (rate, tidal volume and its variability, inspiratory flow rate, duty cycle, and end-tidal pCO(2)) measures. Subjective emotional experience and facial behavior (Corrugator Supercilii and Zygomaticus Major EMG) served as control measures. Results indicated robust differential physiological response patterns for fear, sadness, and neutral (mean classification accuracy 85%). Findings are discussed in terms of the fight-flight and conservation-withdrawal responses and possible limitations of a valence-arousal categorization of emotion in affective space.
View details for DOI 10.1111/j.1469-8986.2007.00550.x
View details for Web of Science ID 000249002200013
View details for PubMedID 17598878
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Psychophysiological effects of breathing instructions for stress management
APPLIED PSYCHOPHYSIOLOGY AND BIOFEEDBACK
2007; 32 (2): 89-98
Abstract
Stressed and tense individuals often are recommended to change the way they breathe. However, psychophysiological effects of breathing instructions on respiration are rarely measured. We tested the immediate effects of short and simple breathing instructions in 13 people seeking treatment for panic disorder, 15 people complaining of daily tension, and 15 controls. Participants underwent a 3-hour laboratory session during which instructions to direct attention to breathing and anti-hyperventilation instructions to breathe more slowly, shallowly, or both were given. Respiratory, cardiac, and electrodermal measures were recorded. The anti-hyperventilation instructions failed to raise end-tidal pCO(2) above initial baseline levels for any of the groups because changes in respiratory rate were compensated for by changes in tidal volume and vice versa. Paying attention to breathing significantly reduced respiratory rate and decreased tidal volume instability compared to the other instructions. Shallow breathing made all groups more anxious than did other instructions. Heart rate and skin conductance were not differentially affected by instructions. We conclude that simple and short instructions to alter breathing do not change respiratory or autonomic measures in the direction of relaxation, except for attention to breathing, which increases respiratory stability. To understand the results of breathing instructions for stress and anxiety management, respiration needs to be monitored physiologically.
View details for DOI 10.1007/s10484-007-9034-x
View details for Web of Science ID 000247932100002
View details for PubMedID 17520360
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Targeting pCO(2) in asthma: Pilot evaluation of a capnometry-assisted breathing training
APPLIED PSYCHOPHYSIOLOGY AND BIOFEEDBACK
2007; 32 (2): 99-109
Abstract
This pilot study aimed to evaluate the feasibility and potential benefits of a novel biofeedback breathing training for achieving sustained increases in pCO(2) levels.Twelve asthma patients were randomly assigned to an immediate 4-week treatment group or waiting list control. Patients were instructed to modify their respiration in order to change levels of end-tidal pCO(2) using a hand-held capnometer. Treatment outcome was assessed in frequency and distress of symptoms, asthma control, lung function, and variability of peak expiratory flow (PEF).We found stable increases in pCO(2) and reductions in respiration rate during treatment and 2-month follow-up. Mean pCO(2) levels rose from a hypocapnic to a normocapnic range at follow-up. Frequency and distress of symptoms was reduced and reported asthma control increased. In addition, mean PEF variability decreased significantly in the treatment group.Our pilot intervention provided evidence for the feasibility of pCO(2)-biofeedback training in asthma patients.
View details for DOI 10.1007/s10484-007-9036-8
View details for Web of Science ID 000247932100003
View details for PubMedID 17564826
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Psychophysiological responses to breathing instructions
12th Annual Meeting of the International-Society-for-the-Advancement-of-Respiratory-Psychophysiology
ELSEVIER SCIENCE BV. 2007: 209–
View details for Web of Science ID 000246753200034
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Clinical anxiety and respiration: Palo Alto studies in progress
12th Annual Meeting of the International-Society-for-the-Advancement-of-Respiratory-Psychophysiology
ELSEVIER SCIENCE BV. 2007: 212–12
View details for Web of Science ID 000246753200042
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Physiological evaluation of psychological treatments for anxiety.
Expert review of neurotherapeutics
2007; 7 (2): 129-141
Abstract
Classification of mental disorders has been greatly influenced by a medical model postulating biological abnormalities that underlie its divisions. Particularly in anxiety disorders, physiological symptoms are part of the Diagnostic and Statistical Manual criteria. Therefore, successful therapy should influence physiological as well as cognitive-verbal expressions of anxiety. Nevertheless, despite the well-known limitations of self-report, physiological outcome measures have only occasionally been employed. We searched the literature for treatment studies that attempted to make a physiological argument for the efficacy of a psychological treatment for anxiety. Our search found only a few methodologically sound examples, where normalization of self-report and physiological measures corresponded. The most convincing studies dealt with the treatment of specific phobias and post-traumatic stress disorder.
View details for PubMedID 17286547
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The Driving Cognitions Questionnaire: Development and preliminary psychometric properties
JOURNAL OF ANXIETY DISORDERS
2007; 21 (4): 493-509
Abstract
Recent research has suggested that fear of driving is common in the general population. People may have various concerns when driving, and instruments for the assessment of these concerns are lacking. The present paper describes the development and preliminary evaluation of the Driving Cognitions Questionnaire (DCQ). The DCQ is a 20-item scale that measures three areas of driving-related concerns--panic-related, accident-related, and social concerns. In three separate samples from different countries (n=69, 100, and 78), the scale showed good internal consistency and substantial correlations with measures of the severity of driving fear. It discriminated well between people with and without driving phobia. It also showed convergent validity with other measures. The questionnaire shows promise for use in research and clinical practice.
View details for DOI 10.1016/j.janxdis.2006.08.002
View details for Web of Science ID 000246948800002
View details for PubMedID 16982173
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The psychophysiology of fear and sadness: Cardiovascular, electrodermal, and respiratory responses during film viewing
47th Annual Meeting of the Society-for-Psychophysiological-Research
WILEY-BLACKWELL. 2007: S20–S20
View details for Web of Science ID 000249001900092
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Affective computing: uSing computational intelligence techniques to classify the psychophysiological signatures of fearful, sad, and calm affective states
47th Annual Meeting of the Society-for-Psychophysiological-Research
WILEY-BLACKWELL. 2007: S110–S111
View details for Web of Science ID 000249001900503
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Muscle relaxation therapy for anxiety disorders: It works but how?
JOURNAL OF ANXIETY DISORDERS
2007; 21 (3): 243-264
Abstract
Muscle relaxation therapy (MRT) has continued to play an important role in the modern treatment of anxiety disorders. Abbreviations of the original progressive MRT protocol [Jacobson, E. (1938). Progressive relaxation (2nd ed.). Chicago: University of Chicago Press] have been found to be effective in panic disorder (PD) and generalized anxiety disorder (GAD). This review describes the most common MRT techniques, summarizes recent evidence of their effectiveness in treating anxiety, and explains their rationale and physiological basis. We conclude that although GAD and PD patients may exhibit elevated muscle tension and abnormal autonomic and respiratory measures during laboratory baseline assessments, the available evidence does not allow us to conclude that physiological activation decreases over the course of MRT in GAD and PD patients, even when patients report becoming less anxious. Better-designed studies will be required to identify the mechanisms of MRT and to advance clinical practice.
View details for DOI 10.1016/j.janxdis.2006.08.001
View details for Web of Science ID 000245868500001
View details for PubMedID 16949248
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Are the psychophysiological responses to voluntary hyperventilation diagnostically specific to panic disorder?
WILEY-LISS. 2007: 371–73
View details for Web of Science ID 000249367100018
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Panic attack symptom dimensions and their relationship to illness characteristics in panic disorder
JOURNAL OF PSYCHIATRIC RESEARCH
2006; 40 (6): 520-527
Abstract
Subtyping panic disorder by predominant symptom constellations, such as cognitive or respiratory, has been done for some time, but criteria have varied considerably between studies. We sought to identify statistically symptom dimensions from intensity ratings of 13 DSM-IV panic symptoms in 343 panic patients interviewed with the Anxiety Disorders Interview Schedule for DSM-IV Lifetime Version. We then explored the relation of symptom dimensions to selected illness characteristics. Ratings were submitted to exploratory maximum likelihood factor analysis with a Promax rotation. A three-factor solution was found to account best for the variance. Symptoms loading highest on the first factor were palpitations, shortness of breath, choking, chest pain, and numbness, which define a cardio-respiratory type (with fear of dying). Symptoms loading highest on the second factor were sweating, trembling, nausea, chills/hot flashes, and dizziness, which defines a mixed somatic subtype. Symptoms loading highest on the third factor were feeling of unreality, fear of going crazy, and fear of losing control, which defines a cognitive subtype. Subscales based on these factors showed moderate intercorrelations. In a series of hierarchical multiple regression analyses, the cardio-respiratory subscale was a strong predictor of panic severity, frequency of panic attacks, and agoraphobic avoidance, while the cognitive subscale mostly predicted worry due to panic. In addition, patients with comorbid asthma had higher scores on the cardio-respiratory subscale. We conclude that partly independent panic symptom dimensions can be identified that have different implications for severity and control of panic disorder.
View details for DOI 10.1016/j.jpsychires.2005.09.006
View details for Web of Science ID 000240250000007
View details for PubMedID 16293263
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Psychophysiological and cortisol responses to psychological stress in depressed and nondepressed older men and women with elevated cardiovascular disease risk
PSYCHOSOMATIC MEDICINE
2006; 68 (4): 538-546
Abstract
The objective of this study was to compare psychophysiological and cortisol reactions to psychological stress in older depressed and nondepressed patients at risk for cardiovascular disease (CVD).Forty-eight depressed participants and 20 controls with elevated cardiovascular risk factors underwent a psychological stress test during which cardiovascular variables were measured. Salivary cortisol was collected after each test segment. Traditional (e.g., lipids) and atypical (e.g., C-reactive protein) CVD risk factors were also obtained.At baseline, the groups did not differ on lipid levels, flow-mediated vasodilation, body mass index, or asymmetric dimethylarginine. However, the depressed patients had significantly higher C-reactive protein levels. Contrary to our hypothesis, there were no differences in baseline cortisol levels or diurnal cortisol slopes, but depressed patients showed significantly lower cortisol levels during the stress test (p = .03) and less cortisol response to stress. Compared with nondepressed subjects, depressed subjects also showed lower levels of respiratory sinus arrhythmia (RSA(TF)) during the stress test (p = .02).In this sample, older depressed subjects with elevated risk for CVD exhibited a hypocortisol response to acute stress. This impaired cortisol response might contribute to chronic inflammation (as reflected in the elevated C-reactive proteins in depressed patients) and in other ways increase CVD risk. The reduced RSA(TF) activity may also increase CVD risk in depressed patients through impaired autonomic nervous system response to cardiophysiological demands.
View details for DOI 10.1097/01.psy.0000222372.16274.92
View details for Web of Science ID 000239330600005
View details for PubMedID 16868262
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Differential effects of film-induced fear and sadness on acoustic startle
46th Annual Meeting of the Society-for-Psychophysiological-Research
WILEY-BLACKWELL PUBLISHING, INC. 2006: S54–S54
View details for Web of Science ID 000239965400249
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Distinguishing emotional from physical activation in ambulatory psychophysiological monitoring
BIOMEDICAL SCIENCES INSTRUMENTATION, VOL 42
2006; 42: 458-463
Abstract
Ambulatory monitoring has gained powerful new tools due to recent electronic and computer advances. The capability simultaneously to monitor numerous physiological parameters and behavior enhances the ecological validity of field assessment, but methodological challenges abound that can compromise attempts to understand biobehavioral relations in the real world. A major obstacle is that physiological dysregulation or emotion effects can be masked by variation in physical activity. Using a multi-channel ambulatory recording system, a wide array of self-report, physiological and environmental measurements was collected from 28 participants during quiet sitting, physical exercise and an emotion induction consisting of a short commercial flight. Half of the participants were selected to respond to flying with intense anxiety, the other half, with moderate excitement. Recorded channels included ECG, EDA, calibrated respiration pattern, and skin temperature, from which 17 physiological parameters were calculated. Accelerometry and self-report in an emotion diary served as manipulation checks. Results indicate that many parameters, including heart rate, respiratory sinus arrhythmia, and skin conductance level and its fluctuation rate, were strongly and nonspecifically affected by both anxiety and exercise. However, parameters of respiratory volume were particularly responsive to exercise, while certain parameters of irregularity in breathing were to anxiety. Several respiratory timing parameters were responsive to both exercise and excitement. We conclude that physiological measures provide information helping to distinguish emotional from physical activation. However, additional context awareness is necessary for confident data interpretation in ambulatory recording. This can be achieved by specific channels such as accelerometry, items in an electronic diary, semi-structured protocols, and statistical modeling.
View details for Web of Science ID 000239353700076
View details for PubMedID 16817651
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Physiological markers for anxiety: Panic disorder and phobias
12th World Congress of Psychophysiology of the International-Organization-of-Psychophysiology
ELSEVIER SCIENCE BV. 2005: 190–98
Abstract
Physiological activation is a cardinal symptom of anxiety, although physiological measurement is still not used for psychiatric diagnosis. An ambulatory study of phobics who were afraid of highway driving showed a concordance between self-reported anxiety during driving, autonomic activation, hypocapnia, and sighing respiration. Patients with panic attacks do not exhibit autonomic activation when they are quietly sitting and not having panic attacks, but do have the same respiratory abnormalities as driving phobics, suggesting that these abnormalities could be a marker for panic disorder. Such abnormalities are compatible with both the false suffocation alarm (D. Klein) and hyperventilation (R. Ley) theories of panic. Hypocapnia, however, is often absent during full-blown panic attacks. Since activation functions as preparation for physical activity, it may not occur when a patient has learned that avoidance of fear by flight or fight is futile. We developed a capnometry feedback assisted breathing training therapy for panic disorder designed to reduce hyperventilation and making breathing regular. Without feedback, conventional therapeutic breathing instructions may actually increase hyperventilation by increasing dyspnea. Five weekly therapy sessions accompanied by daily home practice with a capnometer produced marked clinical improvement compared to changes in an untreated group. Improvement was sustained over a 12-month follow-up period. The therapist avoided any statements or procedures designed to alter cognitions. Improvement occurred regardless of whether patients initially reported mostly respiratory or non-respiratory symptoms during their attacks. There is evidence that modifying any of the three systems comprising a fear network can be therapeutic, as exemplified by cognitive therapy modifying thoughts, exposure therapy modifying avoidance, and breathing training procedures modifying pCO(2).
View details for DOI 10.1016/j.ijpsycho.2005.01.015
View details for Web of Science ID 000233383000010
View details for PubMedID 16137780
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End-tidal pCO(2) in blood phobics during viewing of emotion- and disease-related films
PSYCHOSOMATIC MEDICINE
2005; 67 (4): 661-668
Abstract
Many patients with blood, injection, and injury (BII) phobia respond to specific stimuli with vasovagal dysregulation and fainting. However, little is known about the role of hyperventilation in the distress of these patients. Hyperventilation, defined by subnormal arterial pCO2 levels, induces anxiety and may promote the development of fainting. We studied end-tidal pCO2 in 12 patients with BII phobia and 14 nonanxious controls during presentation of emotional films.Ten film clips were shown, two in each of 5 categories: pleasant, unpleasant, neutral, BII-related (surgery), and asthma-related (portraying labored breathing). For each subject, two subsets were created, each containing one clip from each category. For one subset, the instruction was simply to view the film, and for the other subset, to view the film while tensing the leg muscles. PCO2, heart rate, blood pressure, and leg electromyogram were recorded continuously during viewing, and self-report of symptoms and emotion was collected after each film.Patients reported the greatest anxiety and disgust during surgery films. PCO2 was relatively stable throughout all categories except surgery films, during which minima were below 30 mm Hg, indicating significant hypocapnia. Cardiovascular variables suggested biphasic patterns in two patients with BII phobia. These patients, together with one additional patient and one control who were close to fainting after or during one surgery film, also showed a marked fall in pCO2) Leg muscle tension raised heart rate and systolic blood pressure for all films, but was not related to near-fainting or endurance in surgery film viewing.Hyperventilation is part of the fear response of patients with BII phobia, but was transitory in experimental fear induction using surgery films. Its role in real-life exposure and fainting deserves further study.
View details for DOI 10.1097/01.psy.0000170339.06281.07
View details for Web of Science ID 000230830600025
View details for PubMedID 16046385
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Voluntary hyperventilation in the treatment of panic disorder - functions of hyperventilation, their implications for breathing training, and recommendations for standardization
CLINICAL PSYCHOLOGY REVIEW
2005; 25 (3): 285-306
Abstract
Hyperventilation has numerous theoretical and empirical links to anxiety and panic. Voluntary hyperventilation (VH) tests have been applied experimentally to understand psychological and physiological mechanisms that produce and maintain anxiety, and therapeutically in the treatment of anxiety disorders. From the theoretical perspective of hyperventilation theories of anxiety, VH is useful diagnostically to the clinician and educationally to the patient. From the theoretical perspective of cognitive-behavior therapy, VH is a way to expose patients with panic disorder to sensations associated with panic and to activate catastrophic cognitions that need restructuring. Here we review panic disorder treatment studies using breathing training that have included VH. We differentiate the roles of VH in diagnosis, education about symptoms, training of breathing strategies, interoceptive exposure, and outcome measurement--discussing methodological issues specific to these roles and VH test reliability and validity. We propose how VH procedures might be standardized in future studies.
View details for DOI 10.1016/j.cpr.2005.01.002
View details for Web of Science ID 000228619200002
View details for PubMedID 15792851
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Are current theories of panic falsifiable?
PSYCHOLOGICAL BULLETIN
2005; 131 (2): 171-192
Abstract
The authors examine 6 theories of panic attacks as to whether empirical approaches are capable of falsifying them and their heuristic value. The authors conclude that the catastrophic cognitions theory is least falsifiable because of the elusive nature of thoughts but that it has greatly stimulated research and therapy. The vicious circle theory is falsifiable only if the frightening internal sensations are specified. The 3-alarms theory postulates an indeterminate classification of attacks. Hyperventilation theory has been falsified. The suffocation false alarm theory lacks biological parameters that unambiguously index dyspnea or its distinction between anticipatory and panic anxiety. Some correspondences postulated between clinical phenomena and brain areas by the neuroanatomical hypothesis may be falsifiable if panic does not depend on specific thoughts. All these theories have heuristic value, and their unfalsifiable aspects are capable of modification.
View details for DOI 10.1037/0033-2909.1312.2.171
View details for Web of Science ID 000227423200001
View details for PubMedID 15740414
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Psychophysiological assessment during exposure in driving phobic patients
JOURNAL OF ABNORMAL PSYCHOLOGY
2005; 114 (1): 126-139
Abstract
A comprehensive assessment of fear or anxiety requires measurement of both self-report and physiological responses. Respiratory abnormalities have been rarely examined during real-life exposure, although they are an integral part of fear. Twenty-one women with a specific driving phobia and 17 nonphobic women were psychophysiologically monitored during 2 highway-driving sessions; phobic women completed an additional session. Respiratory movements, end-tidal partial pressure of carbon dioxide, an electrocardiogram, skin conductance, and skin temperature were recorded. Phobic patients differed from control participants both physiologically and experientially before, during, and after exposure. Effect size during exposure was large for the authors' measure of hyperventilation. Discriminant analysis indicated that multiple physiological measures contributed nonredundant information and correctly classified 95% of phobic and control participants. Thus, selected respiratory and autonomic measures are valid diagnostic and therapeutic outcome criteria for this situational phobia.
View details for DOI 10.1037/0021-843X.114.1.126
View details for Web of Science ID 000227146600013
View details for PubMedID 15709819
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Standardized assessment of diurnal vagal activity in depressed patients with risk for coronary artery disease: accounting for physical activity, respiration, and mood variability
10th Annual Meeting of the International-Society-for-the-Advancement-of-Respiratory-Psychophysiology
ELSEVIER SCIENCE BV. 2004: 410–10
View details for Web of Science ID 000223441300028
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Behavioral interventions in asthma biofeedback techniques
JOURNAL OF PSYCHOSOMATIC RESEARCH
2004; 56 (6): 711-720
Abstract
Biofeedback techniques have long been recommended as an adjunctive treatment for bronchial asthma. Techniques that target lung function directly, or indirectly by altering facial muscle tension, heart rate, heart rate variability (HRV) or inspiratory volume together with accessory muscle tension, have been proposed. We review evidence for the effectiveness of these biofeedback interventions and discuss the psychophysiological rationale behind individual techniques.Controlled studies of biofeedback in asthma were retrieved using relevant search engines and reference lists of published articles. Effect sizes comparing intervention with control groups were calculated where appropriate.Most of the studies suffer from methodological inadequacies or poor reporting of methods and results. Interventions targeting respiratory resistance directly have yielded only small and inconsistent changes in lung function and are difficult to implement without producing dynamic hyperinflation. Biofeedback-assisted facial muscle relaxation as an indirect intervention has yielded mixed results across studies, with only half of the studies showing significant albeit very small and clinically irrelevant improvements in lung function. The underlying physiological assumptions of the technique are questionable in the light of current knowledge of respiratory physiology. For other indirect techniques, only preliminary evidence of small effects is available.Currently, there is little good evidence that biofeedback techniques can contribute substantially to the treatment of asthma.
View details for DOI 10.1016/S0022-3999(03)00131-4
View details for Web of Science ID 000222284200010
View details for PubMedID 15193969
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Deficient response modulation of event-related brain potentials in schizophrenia
CURRENT OPINION IN PSYCHIATRY
2004; 17 (2): 91-96
View details for DOI 10.1097/01.yco.0000120426.39447.76
View details for Web of Science ID 000220089600004
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Respiratory feedback for treating panic disorder
JOURNAL OF CLINICAL PSYCHOLOGY
2004; 60 (2): 197-207
Abstract
Panic disorder patients often complain of shortness of breath or other respiratory complaints, which has been used as evidence for both hyperventilation and false suffocation alarm theories of panic. Training patients to change their breathing patterns is a common intervention, but breathing rarely has been measured objectively in assessing the patient or monitoring therapy results. We report a new breathing training method that makes use of respiratory biofeedback to teach individuals to modify four respiratory characteristics: increased ventilation (Respiratory Rate x Tidal Volume), breath-to-breath irregularity in rate and depth, and chest breathing. As illustrated by a composite case, feedback of respiratory rate and end-tidal pCO2 can facilitate voluntary control of respiration and reduce symptoms. Respiratory monitoring may provide relevant diagnostic, prognostic, and outcome information.
View details for DOI 10.1002/jclp.10245
View details for Web of Science ID 000188430200007
View details for PubMedID 14724927
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Circadian positive and negative affect and heart rate variability in depressed and nondepressed individuals at risk for cardiovascular disease
HOGREFE & HUBER PUBLISHERS. 2004: 227–27
View details for Web of Science ID 000226087400114
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Situational and individual response specificity to emotion films: Effects on experiential, cardiovascular, electrodermal, respiratory and somatic responses
44th Annual Meeting of the Society-for-Psychophysiological-Research
WILEY-BLACKWELL. 2004: S75–S75
View details for Web of Science ID 000223558200288
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The LifeShirt - An advanced system for ambulatory measurement of respiratory and cardiac function
BEHAVIOR MODIFICATION
2003; 27 (5): 671-691
Abstract
An accurate ambulatory breathing monitor is needed to observe acute respiratory changes in patients with medical or psychological disorders outside the clinic (e.g., hyperventilation during panic or apneas during sleep). Significant limitations of existing monitors are size, troublesome operation, and difficulty holding chest and abdomen bands in place during 24-hour recordings. Recently, a garment has been developed with embedded inductive plethysmography sensors for continuous ambulatory monitoring of respiration, heart activity, inductive cardiography, motility, postural changes, and other functions. The signals are displayed and stored on a handheld computer (Visor), and then analyzed offline, extracting more than 40 clinical parameters relating to cardiorespiratory function (e.g., heart rate, respiratory sinus arrhythmia, tidal volume, stroke volume, pre-ejection period, apnea-hypopnea index, thoraco-abdominal coordination, sighing). The device also serves as an electronic diary of symptoms, moods, and activities. This advanced system may open a new era in ambulatory monitoring for clinical practice and scientific research.
View details for DOI 10.1177/0145445503256321
View details for Web of Science ID 000185192800006
View details for PubMedID 14531161
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Behavioral interventions in asthma - Breathing training
BEHAVIOR MODIFICATION
2003; 27 (5): 710-730
Abstract
Breathing exercises are frequently recommended as an adjunctive treatment for asthma. A review of the current literature found little that is systematic documenting the benefits of these techniques in asthma patients. The physiological rationale of abdominal breathing in asthma is not clear, and adverse effects have been reported in chronic obstructive states. Theoretical analysis and empirical observations suggest positive effects of pursed-lip breathing and nasal breathing but clinical evidence is lacking. Modification of breathing patterns alone does not yield any significant benefit. There is limited evidence that inspiratory muscle training and hypoventilation training can help reduce medication consumption, in particular beta-adrenergic inhaler use. Breathing exercises do not seem to have any substantial effect on parameters of basal lung function. Additional research is needed on the psychological and physiological mechanisms of individual breathing techniques in asthma, differential effects in subgroups of asthma patients, and the generalization of training effects on daily life.
View details for DOI 10.1177/0145445503256323
View details for Web of Science ID 000185192800008
View details for PubMedID 14531163
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Breathing training for treating panic disorder - Useful intervention or impediment?
BEHAVIOR MODIFICATION
2003; 27 (5): 731-754
Abstract
Breathing training (BT) is commonly used for treatment of panic disorder. We identified nine studies that reported the outcome of BT. Overall, the published studies of BT are not sufficiently compelling to allow an unequivocal judgment of whether such techniques are beneficial. This article discusses problems with the underlying rationale, study design, and techniques used in BT, and it identifies factors that may have determined therapy outcomes. The idea that hypocapnia and respiratory irregularities are underlying factors in the development of panic implies that these factors should be monitored physiologically throughout therapy. Techniques taught in BT must take account of respiration rate and tidal volume in the regulation of blood gases (pCO2). More studies are needed that are designed to measure the efficacy of BT using an adequate rationale and methodology. Claims that BT should be rejected in favor of cognitive or other forms of intervention are premature.
View details for DOI 10.1177/0145445503256324
View details for Web of Science ID 000185192800009
View details for PubMedID 14531164
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Salivary cortisol response during exposure treatment in driving phobics
PSYCHOSOMATIC MEDICINE
2003; 65 (4): 679-687
Abstract
Extensive research on the hypothalamic-pituitary-adrenal (HPA) axis response to stress has not clarified whether that axis is activated by phobic anxiety. We addressed this issue by measuring cortisol in situational phobics during exposure treatment.Salivary cortisol was measured in 11 driving phobics before and during three exposure sessions involving driving on crowded limited-access highways and compared with levels measured in 13 healthy controls before and during two sessions of driving on the same highways. For each subject, data collected in the same time period on a comparison nondriving day served as an individual baseline from which cortisol response scores were calculated.Cortisol levels of driving phobics and controls did not differ on the comparison day. Phobics also had normal cortisol response scores on awakening on the mornings of the exposures but these were already increased 1 hour before coming to the treatment sessions. Phobics had significantly greater cortisol response scores during driving exposure and during quiet sitting periods before and afterward. These greater responses generally paralleled increases in self-reported anxiety. At the first exposure session, effect sizes for differences in cortisol response scores between the two groups were large. Initial exposure to driving in the first session evoked the largest responses.The data demonstrate that the HPA axis can be strongly activated by exposure to, and anticipation of, a phobic situation.
View details for DOI 10.1097/01.PSY.0000073872.85623.0C
View details for Web of Science ID 000184362200030
View details for PubMedID 12883122
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Predictors of response in anxiety disorders
PSYCHIATRIC CLINICS OF NORTH AMERICA
2003; 26 (2): 411-?
Abstract
Anxiety disorder variables such as duration, severity of illness, and comorbidity with other anxiety or mood disorders appear to identify individuals who are at the greatest risk of treatment nonresponse. Conversely, in accord with clinical experience, shorter periods of illness, less severe illness, being treatment naive, and the absence of comorbidity tend to identify patients who are likely to respond robustly to medication management. Symptom clusters in OCD and PTSD are promising as a means of stratifying those more likely to respond to standard pharmacologic treatment. The presence of hoarding or sexual obsessions seems to presage poorer response in OCD, while the presence of dissociative symptoms in PTSD has been linked to high nonspecific treatment response rates to placebo. Genotyping individuals with respect to genes that are thought to have an important role in the underlying disease process, such as the work with the 5HTTL-PR allele, is exciting and is perhaps the first glimmer of using genotyping to identify treatment strategies or to predict the likelihood or speed of response. The use of neuroimaging as a means of identifying individuals who may respond favorably to pharmacologic or neurosurgical intervention is still in its infancy. As a strategy, it may help combine symptom severity and response variables into a clear neurobiologic vulnerability model of illness. In the future, it may be possible to identify specific treatment interventions for specific patterns of abnormal metabolic rates in certain areas of the brain. However, it should be emphasized that such an approach has not been empirically demonstrated in a rigorous experimental context at this time.
View details for DOI 10.1016/S0193-953X(03)00027-3
View details for Web of Science ID 000182929300008
View details for PubMedID 12778841
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A new technology for 24-h assessment of RSA with control for respiratory and physical activity variation
ELSEVIER SCIENCE BV. 2003: 241–42
View details for Web of Science ID 000181920500041
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Detection of speaking with a new respiratory inductive plethysmography system
40th Annual Rocky Mountain Bioengineering Symposium/40th International ISA Biomedical Sciences Instrumentation Symposium
INSTRUMENT SOC AMER. 2003: 136–141
Abstract
The LifeShirt system, a garment with integrated sensors connected to a handheld computer, allows recording of a wide variety of clinically important cardiorespiratory data continuously for extended periods outside the laboratory or clinic. The device includes sensors for assessment of physical activity and posture since both can affect physiological activation and need to be controlled. Speaking is another potential confounding factor in the interpretation of physiological data. Auditory speech recording is problematic because it can pick up sources other than the person's voice (external microphone) or is obtrusive (throat microphone). The abdominal and thoracic calibrated respiratory inductive plethysmography (RIP) sensors integrated in the LifeShirt system might be an adequate alternative for detecting speech. In a laboratory experiment we determined respiratory parameters indicative of speech. Eighteen subjects were instructed to sit quietly, write, and speak continuously, for 4 min each. Nine parameters were derived from the RIP signals and averaged over each minute. In addition, nine variability parameters were computed as their coefficients of breath-by-breath variation. Inspiratory/expiratory time (IE-ratio) best distinguished speaking from writing with 98% correct classification at a cutoff criterion of 0.52. This criterion was equally successful in distinguishing speaking from sitting quietly. Discriminant analyses indicated that linear combinations of IE-ratio and a variety of other parameters did not reliably improve classification accuracy across tasks and replications. These results demonstrate the high efficacy of RIP-derived IE-ratio for speech detection and suggest that auditory recording is not necessary for detection of speech in ambulatory assessment.
View details for Web of Science ID 000182321800024
View details for PubMedID 12724882
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Selective attention in piety: Distraction and enhancement in visual search
DEPRESSION AND ANXIETY
2003; 18 (1): 18-28
Abstract
According to cognitive models of anxiety, anxiety patients exhibit an attentional bias towards threat, manifested as greater distractibility by threat stimuli and enhanced detection of them. Both phenomena were studied in two experiments, using a modified visual search task, in which participants were asked to find single target words (GAD-related, speech-related, neutral, or positive) hidden in matrices made up of distractor words (also GAD-related, speech-related, neutral, or positive). Generalized anxiety disorder (GAD) patients, social phobia (SP) patients afraid of giving speeches, and healthy controls participated in the visual search task. GAD patients were slowed by GAD-related distractor words but did not show statistically reliable evidence of enhanced detection of GAD-related target words. SP patients showed neither distraction nor enhancement effects. These results extend previous findings of attentional biases observed with other experimental paradigms.
View details for DOI 10.1002/da.10105
View details for Web of Science ID 000184790800003
View details for PubMedID 12900949
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Embarrassment and social phobia: the role of parasympathetic activation
JOURNAL OF ANXIETY DISORDERS
2003; 17 (2): 197-210
Abstract
The few studies on the psychophysiology of embarrassment have suggested involvement of parasympathetic activation. However, blushing, the hallmark of embarrassment and a prominent symptom in social phobia, is more likely to be produced by cervical sympathetic outflow. Hitherto, there has been no evidence of parasympathetic innervation of the facial blood vessels. In this study, a group of social phobics and control participants watched, together with a 2-person audience, a previously made videotape of themselves singing a children's song. Self-report measures confirmed that this task induced embarrassment. While two measures of respiratory sinus arrhythmia (RSA) during the task did not indicate heightened parasympathetic tone, increased heart rate (HR) and skin conductance marked sympathetic activation. Thus, our data do not support the notion that an increase in parasympathetic activation plays a significant role in social phobia and embarrassment. Social anxiety and embarrassment both resulted in sympathetic activation.
View details for Web of Science ID 000181646200005
View details for PubMedID 12614662
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A NARRATIVE EXPOSURE TREATMENT AS INTERVENTION IN A REFUGEE CAMP: A CASE REPORT
BEHAVIOURAL AND COGNITIVE PSYCHOTHERAPY
2002; 30 (2): 205-209
View details for DOI 10.1017/S1352465802002072
View details for Web of Science ID 000207888200007
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Reduced communication between frontal and temporal lobes during talking in schizophrenia
BIOLOGICAL PSYCHIATRY
2002; 51 (6): 485-492
Abstract
Communication between the frontal lobes, where speech and verbal thoughts are generated, and the temporal lobes, where they are perceived, may occur through the action of a corollary discharge. Its dysfunction may underlie failure to recognize inner speech as self-generated and account for auditory hallucinations in schizophrenia.Electroencephalogram was recorded from 10 healthy adults and 12 patients with schizophrenia (DSM-IV) in two conditions: talking aloud and listening to their own played-back speech. Event-related electroencephalogram coherence to acoustic stimuli presented during both conditions was calculated between frontal and temporal pairs, for delta, theta, alpha, beta, and gamma frequency bands.Talking produced greater coherence than listening between frontal-temporal regions in all frequency bands; however, in the lower frequencies (delta and theta), there were significant interactions of group and condition. This finding revealed that patients failed to show an increase in coherence during talking, especially over the speech production and speech reception areas of the left hemisphere, and especially in patients prone to hallucinate.Reduced fronto-temporal functional connectivity may contribute to the misattribution of inner thoughts to external voices in schizophrenia.
View details for Web of Science ID 000174739000008
View details for PubMedID 11922884
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High altitudes, anxiety, and panic attacks: Is there a relationship?
DEPRESSION AND ANXIETY
2002; 16 (2): 51-58
Abstract
People exposed to high altitudes often experience somatic symptoms triggered by hypoxia, such as breathlessness, palpitations, dizziness, headache, and insomnia. Most of the symptoms are identical to those reported in panic attacks or severe anxiety. Potential causal links between adaptation to altitude and anxiety are apparent in all three leading models of panic, namely, hyperventilation (hypoxia leads to hypocapnia), suffocation false alarms (hypoxia counteracted to some extent by hypocapnia), and cognitive misinterpretations (symptoms from hypoxia and hypocapnia interpreted as dangerous). Furthermore, exposure to high altitudes produces respiratory disturbances during sleep in normals similar to those in panic disorder at low altitudes. In spite of these connections and their clinical importance, evidence for precipitation of panic attacks or more gradual increases in anxiety during altitude exposure is meager. We suggest some improvements that could be made in the design of future studies, possible tests of some of the theoretical causal links, and possible treatment applications, such as systematic exposure of panic patients to high altitude.
View details for DOI 10.1002/da.10059
View details for Web of Science ID 000178260700001
View details for PubMedID 12219335
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The lifeshirt system: A new technology for 24-hr assessment of RSA with control for respiratory and physical activity variation
BLACKWELL PUBLISHING. 2002: S87–S87
View details for Web of Science ID 000177939700344
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Neurophysiological evidence of corollary discharge dysfunction in schizophrenia
AMERICAN JOURNAL OF PSYCHIATRY
2001; 158 (12): 2069-2071
Abstract
Speaking is hypothesized to generate a corollary discharge of motor speech commands transmitted to the auditory cortex, dampening its response to self-generated speech sounds. Event-related potentials were used to test whether failures of corollary discharge during speech contribute to the pathophysiology of schizophrenia.The N1 component of the event-related potential elicited by vowels was recorded while the vowels were spoken by seven patients with schizophrenia and seven healthy comparison subjects and while the same vowels were played back.In the healthy subjects, the N1 elicited by spoken vowels was smaller than the N1 elicited by played-back vowels. This reduction in N1 elicited by spoken vowels was not observed in the patients with schizophrenia.These findings provide direct neurophysiological evidence for a corollary discharge that dampens sensory responses to self-generated, relative to externally presented, percepts in healthy comparison subjects and its failure in patients with schizophrenia.
View details for Web of Science ID 000172452100023
View details for PubMedID 11729029
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Social anxiety and response to touch: incongruence between self-evaluative and physiological reactions
40th Annual Meeting of the Society-for-Psychophysiological-Research
ELSEVIER SCIENCE BV. 2001: 181–202
Abstract
Touch is an important form of social interaction, and one that can have powerful emotional consequences. Appropriate touch can be calming, while inappropriate touch can be anxiety provoking. To examine the impact of social touching, this study compared socially high-anxious (N=48) and low-anxious (N=47) women's attitudes concerning social touch, as well as their affective and physiological responses to a wrist touch by a male experimenter. Compared to low-anxious participants, high-anxious participants reported greater anxiety to a variety of social situations involving touch. Consistent with these reports, socially anxious participants reacted to the experimenter's touch with markedly greater increases in self-reported anxiety, self-consciousness, and embarrassment. Physiologically, low-anxious and high-anxious participants showed a distinct pattern of sympathetic-parasympathetic coactivation, as reflected by decreased heart rate and tidal volume, and increased respiratory sinus arrhythmia, skin conductance, systolic/diastolic blood pressure, stroke volume, and respiratory rate. Interestingly, physiological responses were comparable in low and high-anxious groups. These findings indicate that social anxiety is accompanied by heightened aversion towards social situations that involve touch, but this enhanced aversion and negative-emotion report is not reflected in differential physiological responding.
View details for Web of Science ID 000172496600001
View details for PubMedID 11698114
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Cortical responsiveness during inner speech in schizophrenia: An event-related potential study
AMERICAN JOURNAL OF PSYCHIATRY
2001; 158 (11): 1914-1916
Abstract
The study assessed the effects of inner speech on auditory cortical responsiveness in schizophrenia.Comparison subjects (N=15) and patients with schizophrenia (N=15) were presented with acoustic and visual stimuli during three conditions: while subjects were silent, when spontaneous inner speech might occur; during directed inner speech, while subjects repeated a statement silently to themselves; and while subjects listened to recorded speech. N1 event-related potentials were recorded during the three conditions.N1 event-related potentials elicited by acoustic stimuli, but not by visual stimuli, were lower during directed inner speech than during the silent baseline condition in the comparison subjects but not in the patients.Abnormal auditory cortical responsiveness to inner speech in patients with schizophrenia may be a sign of corollary discharge dysfunction, which may potentially cause misattribution of inner speech to external voices.
View details for Web of Science ID 000171946300022
View details for PubMedID 11691701
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Cortical responsiveness during talking and listening in schizophrenia: An event-related brain potential study
BIOLOGICAL PSYCHIATRY
2001; 50 (7): 540-549
Abstract
Failures to recognize inner speech as self-generated may underlie positive symptoms of schizophrenia-like auditory hallucinations. This could result from a faulty comparison in auditory cortex between speech-related corollary discharge and reafferent discharges from thinking or speaking, with misattribution of internal thoughts to external sources. Although compelling, failures to monitor covert speech (thoughts) are not as amenable to investigation as failures to monitor overt speech (talking).Effects of talking on auditory cortex responsiveness were assessed in 10 healthy adults and 12 patients with schizophrenia (DSM-IV) using N1 event-related potentials (ERPs) to acoustic and visual probes during talking aloud, listening to one's speech played back, and silent baseline. Trials contaminated by muscle artifact while talking were excluded.Talking and listening affected N1 to acoustic but not to visual probes, reflecting modality specificity of effects. Patterns of responses to acoustic probes differed between control subjects and patients. N1 to acoustic probes was reduced during talking compared with baseline in control subjects, but not in patients. Listening reduced N1 equivalently in both groups.Although the failure of N1 to be reduced during talking was not related to current hallucinations in patients, it may be related to the potential to hallucinate.
View details for Web of Science ID 000171582200008
View details for PubMedID 11600107
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Respiratory biofeedback-assisted therapy in panic disorder
BEHAVIOR MODIFICATION
2001; 25 (4): 584-605
Abstract
The authors describe a new methodologically improved behavioral treatment for panic patients using respiratory biofeedback from a handheld capnometry device. The treatment rationale is based on the assumption that sustained hypocapnia resulting from hyperventilation is a key mechanism in the production and maintenance of panic. The brief 4-week biofeedback therapy is aimed at voluntarily increasing self-monitored end-tidal partial pressure of carbon dioxide (PCO2) and reducing respiratory rate and instability through breathing exercises in patients' environment. Preliminary results from 4 patients indicate that the therapy was successful in reducing panic symptoms and other psychological characteristics associated with panic disorder. Physiological data obtained from home training, 24-hour ambulatory monitoring pretherapy and posttherapy, and laboratory assessment at follow-up indicate that patients started out with low resting PCO2 levels, increased those levels during therapy, and maintained those levels at posttherapy and/or follow-up. Partial dissociation between PCO2 and respiratory rate questions whether respiratory rate should be the main focus of breathing training in panic disorder.
View details for Web of Science ID 000170514300006
View details for PubMedID 11530717
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Respiratory dysregulation in anxiety, functional cardiac, and pain disorders - Assessment, phenomenology, and treatment
BEHAVIOR MODIFICATION
2001; 25 (4): 513-545
Abstract
Respiration is a complex physiological system affecting a variety of physical processes that can act as a critical link between mind and body. This review discusses the evidence for dysregulated breathing playing a role in three clinical syndromes: panic disorder, functional cardiac disorder, and chronic pain. Recent technological advances allowing the ambulatory assessment of endtidal partial pressure of CO2 (PCO2) and respiratory patterns have opened up new avenues for investigation and treatment of these disorders. The latest evidence from laboratories indicates that subtle disturbances of breathing, such as tidal volume instability and sighing, contribute to the chronic hypocapnia often found in panic patients. Hypocapnia is also common in functional cardiac and chronic pain disorders, and studies indicate that it mediates some of their symptomatology. Consistent with the role of respiratory dysregulation in these disorders, initial evidence indicates efficacy of respiration-focused treatment.
View details for Web of Science ID 000170514300003
View details for PubMedID 11530714
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Slow recovery from voluntary hyperventilation in panic disorder
PSYCHOSOMATIC MEDICINE
2001; 63 (4): 638-649
Abstract
Because hyperventilation has figured prominently in theories of panic disorder (PD) but not of social phobia (SP), we compared predictions regarding diagnosis-specific differences in psychological and physiological measures before, during, and after voluntary hyperventilation.Physiological responses were recorded in 14 patients with PD, 24 patients with SP, and 24 controls during six cycles of 1-minute of fast breathing alternating with 1 minute of recovery, followed by 3 minutes of fast breathing and 10 minutes of recovery. Speed of fast breathing was paced by a tone modulated at 18 cycles/minute, and depth by feedback aimed at achieving an end-tidal pCO2 of 20 mm Hg. These values were reached equally by all groups.During fast breathing, PD and SP patients reported more anxiety than controls, and their feelings of dyspnea and suffocation increased more from baseline. Skin conductance declined more slowly in PD over the six 1-minute fast breathing periods. At the end of the final 10-minute recovery, PD patients reported more awareness of breathing, dyspnea, and fear of being short of breath, and their pCO2s, heart rates, and skin conductance levels had returned less toward normal levels than in other groups. Their lower pCO2s were associated with a higher frequency of sigh breaths.PD and SP patients report more distress than controls to equal amounts of hypocapnia, but PD differ from SP patients and controls in having slower symptomatic and physiological recovery. This finding was not specifically predicted by hyperventilation, cognitive-behavioral, or suffocation alarm theories of PD.
View details for Web of Science ID 000170119800015
View details for PubMedID 11485118
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The somatic symptom paradox in DSM-IV anxiety disorders: suggestions for a clinical focus in psychophysiology
BIOLOGICAL PSYCHOLOGY
2001; 57 (1-3): 105-140
Abstract
Although DSM-IV criteria for anxiety disorders include physiological symptoms, these symptoms are evaluated exclusively by verbal report. The current review explores the background for this paradox and tries to demonstrate on theoretical and empirical grounds how it could be resolved, providing new insights about the role of psychophysiological measures in the clinic. The three-systems approach to evaluating anxiety argues that somatic measures as well as verbal and behavioral ones are indispensable. However, the low concordance between these domains of measurement impugns their reliability and validity. We argue that concordance can be improved by examining the relationship of variables less global than anxiety and by restriction to specific anxiety disorders. For example, recent evidence from our and other laboratories indicate a prominent role of self-reported and physiologically measured breathing irregularities in panic disorder. Nonetheless, even within a diagnosis, anxiety patients vary radically in which somatic variables are deviant. Thus, in clinical practice, individual profiles of psychological and physiological anxiety responses may be essential to indicate distinct therapeutic approaches and ways of tracking improvement. Laboratory provocations specific to certain anxiety disorders and advances in ambulatory monitoring vastly expand the scope of self-report and physiological measurement and will likely contribute to a refined assessment of anxiety disorders.
View details for Web of Science ID 000170196500006
View details for PubMedID 11454436
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Blushing and physiological arousability in social phobia
JOURNAL OF ABNORMAL PSYCHOLOGY
2001; 110 (2): 247-258
Abstract
Blushing is the most prominent symptom of social phobia, and fear perception of visible anxiety symptoms is an important component of cognitive behavioral models of social phobia. However, it is not clear how physiological and psychological aspects of blushing and other somatic symptoms are linked in this disorder. The authors tested whether social situations trigger different facial blood volume changes (blushing) between social phobic persons with and without primary complaint of blushing and control participants. Thirty social phobic persons. 15 of whom were especially concerned about blushing, and 14 control participants were assessed while watching an embarrassing videotape, holding a conversation, and giving a talk. Only when watching the video did the social phobic persons blush more than controls blushed. Social phobic persons who complained of blushing did not blush more intensely than did social phobic persons without blushing complaints but had higher heart rates, possibly reflecting higher arousability of this subgroup.
View details for Web of Science ID 000170879900006
View details for PubMedID 11358019
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The emotional Stroop effect in anxiety disorders - General emotionality or disorder specificity?
JOURNAL OF ANXIETY DISORDERS
2001; 15 (3): 147-159
Abstract
Selective attentional biases, often documented with a modified Stroop task, are considered to play an important role in the etiology and maintenance of anxiety. Two competing explanations for these effects are selectivity for highly emotional words in general vs. selectivity for disorder-specific words. We tested these explanations in 32 patients with generalized anxiety disorder (GAD), 29 patients with social phobia (SP), and 31 non-anxious controls. Stimuli were of four kinds: GAD-related words, SP-related words, words with a neutral valence, and words with a positive valence. Different attentional biases were observed: GAD patients were slowed by all types of emotional words, while SP patients were distracted specifically by speech-related words.
View details for Web of Science ID 000169340800001
View details for PubMedID 11442135
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Physiologic instability in panic disorder and generalized anxiety disorder
BIOLOGICAL PSYCHIATRY
2001; 49 (7): 596-605
Abstract
Because panic attacks can be accompanied by surges in physiologic activation, we tested the hypothesis that panic disorder is characterized by fluctuations of physiologic variables in the absence of external triggers.Sixteen patients with panic disorder, 15 with generalized anxiety disorder, and 19 normal control subjects were asked to sit quietly for 30 min. Electrodermal, cardiovascular, and respiratory measures were analyzed using complex demodulation to quantify variability in physiologic indices.Both patient groups reported equally more anxiety and cardiac symptoms than control subjects, but certain other somatic symptoms, including breathlessness, were elevated only in panic disorder patients. Mean end-tidal pCO(2) and respiratory rates were lower, and tidal volume and the number of sighs were higher in panic disorder patients than control subjects. Neither cardiovascular (heart rate, arterial pressure, cardiac output), nor electrodermal instability including sighs distinguished the groups; however, tidal volume instability was greater in panic disorder than generalized anxiety disorder patients or control subjects. Several other respiratory measures (pCO(2), respiratory rate, minute volume, duty cycle) showed greater instability in both patient groups than in control subjects.Respiration is particularly unstable in panic disorder, underlining the importance of respiratory physiology in understanding this disorder. Whether our findings represent state or trait characteristics is discussed.
View details for Web of Science ID 000167899700006
View details for PubMedID 11297717
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Characteristics of sighing in panic disorder
BIOLOGICAL PSYCHIATRY
2001; 49 (7): 606-614
Abstract
Sighs, breaths with larger tidal volumes than surrounding breaths, have been reported as being more frequent in patients with anxiety disorders.Sixteen patients with panic disorder, 15 with generalized anxiety disorder, and 19 normal control subjects were asked to sit quietly for 30 min. Respiratory volumes and timing were recorded with inductive plethysmography and expired pCO(2), from nasal prongs.Panic disorder patients sighed more and had tonically lower end-tidal pCO(2)s than control subjects, whereas generalized anxiety disorder patients were intermediate. Sighs defined as >2.0 times the subject mean discriminated groups best. Sigh frequency was more predictive of individual pCO(2) levels than was minute volume. Ensemble averaging of respiratory variables for sequences of breaths surrounding sighs showed no evidence that sighs were triggered by increased pCO(2) or reduced tidal volume in any group. Sigh breaths were larger in panic disorder patients than in control subjects. After sighs, pCO(2) and tidal volume did not return to baseline levels as quickly in panic disorder patients as in control subjects.Hypocapnia in panic disorder patients is related to sigh frequency. In none of the groups was sighing a homeostatic response. Panic disorder patients show less peripheral chemoreflex gain than control subjects, which would maintain low pCO(2) levels after sighing.
View details for Web of Science ID 000167899700007
View details for PubMedID 11297718
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Computer-assisted cognitive behavioral group therapy for social phobia
BEHAVIOR THERAPY
2001; 32 (1): 155-165
View details for Web of Science ID 000171068100012
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Characteristics of worry in GAD patients, social phobics, and controls
DEPRESSION AND ANXIETY
2001; 13 (2): 89-96
Abstract
Phenomenological features of worry such as thought content, subjective experience of worry, and efforts to control were investigated in the present interview study, as well as retrospective information about possible origins. To examine the clinical specificity of worrying in Generalized Anxiety Disorder (GAD), 36 GAD patients were compared to a normal control group (N = 30) and to a clinical control group (N = 22 social phobics). GAD patients differed from both groups in having higher frequency of worry, higher number of different worry topics, lower subjective controllability, more accompanying bodily symptoms, and more distress during worry. Thus, in general, our data confirm the central and specific role of worrying in GAD. Furthermore, in contrast to other topics, worrying about daily hassles was specific to GAD patients, which represents a lower threshold for starting to worry.
View details for Web of Science ID 000167740200004
View details for PubMedID 11301925
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Respiratory factors in clinical psychophysiology and biofeedback
VERHALTENSTHERAPIE
2000; 10 (4): 258-271
View details for Web of Science ID 000166470100006
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Psychophysiological assessment: clinical applications for PTSD
JOURNAL OF AFFECTIVE DISORDERS
2000; 61 (3): 225-240
Abstract
Descriptions of anxiety disorders clearly recognize the physiological features of anxiety, yet in most clinical practice and research there is little actual use of physiological measurement. This is unfortunate because a potentially important source of information is thereby unavailable and is likely to result in judgements about emotional experience that are less accurate, complete, and reliable than those that include physiological information. The neglect of physiological measures may result from a variety of concerns regarding test attributes such as reliability, validity, utility, and complexity. Promising results from studies of posttraumatic stress disorder (PTSD) demonstrate that physiological assessment can provide valuable clinical and theoretical insight. Numerous studies have now shown that heightened physiological reactivity to trauma-related cues is highly indicative of a diagnosis of PTSD. Physiological tests have achieved some success in predicting the development and persistence of PTSD, and in predicting and assessing treatment response. Studies of the startle response, aversive conditioning, and brain potentials during cognitive processing have identified several potentially important differences between PTSD patients and controls. This paper provides an overview of psychophysiological findings in PTSD and considers potential clinical applications of psychophysiological assessment for this disorder.
View details for Web of Science ID 000166745500008
View details for PubMedID 11163424
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Improving the clinical sensitivity of noninvasive assessment of cardiac vagal control
WILEY-BLACKWELL. 2000: S105–S105
View details for Web of Science ID 000089900500426
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Event-related potential correlates of acquisition and retrieval of verbal associations in schizophrenics and controls
JOURNAL OF PSYCHOPHYSIOLOGY
2000; 14 (2): 87-96
View details for Web of Science ID 000087631300002
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Failures of automatic and strategic processing in schizophrenia: comparisons of event-related brain potential and startle blink modification
SCHIZOPHRENIA RESEARCH
1999; 37 (2): 149-163
Abstract
Noises elicit startle blinks that are inhibited when immediately (approximately 100 ms) preceded by non-startling prepulses, perhaps reflecting automatic sensory gating. Startle blinks are facilitated when preceded by prepulses at longer lead intervals, perhaps reflecting strategic processes. Event-related brain potentials (ERPs) and startle blinks were used to investigate the well-documented prepulse inhibition failure in schizophrenia. Blinks and ERPs were recorded from 15 schizophrenic men and 20 age-matched controls to noises alone and to noises preceded by prepulses at 120 (PP120), 500 (PP500) and 4000 ms (PP4000) lead intervals. Neither blinks nor any of the ERP components elicited by the noise alone differentiated schizophrenics from controls, although responses to noises were modified by prepulses differently in the two groups. With the N1 component of the ERP, patients showed normal inhibition but lacked facilitation, and with P2, patients lacked inhibition, but showed normal facilitation. With reflex blinks and P300, inhibition was seen in both groups, but no facilitation. These results suggest that different neural circuits are involved in blink and cortical reflections of startle modification in schizophrenics and controls, with both automatic and strategic processes being impaired in schizophrenia.
View details for Web of Science ID 000080583700003
View details for PubMedID 10374650
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Explicit memory in anxiety disorders
JOURNAL OF ABNORMAL PSYCHOLOGY
1999; 108 (1): 153-163
Abstract
Two experiments were conducted to study selective memory bias favoring anxiety-relevant materials in patients with anxiety disorders. In the 1st experiment, 32 patients with generalized anxiety disorder (GAD), 30 with social phobia (speaking anxiety), and 31 control participants incidentally learned GAD-relevant words, speech anxiety-relevant words, strongly pleasant words, and words with a neutral valence. Participants did not show any explicit memory bias for threatening materials. Thirty patients suffering from panic disorder (PD) with agoraphobia and 30 controls took part in the 2nd experiment. The design was similar to the 1st experiment. This time a highly specific selective memory bias for threatening words was found. Words describing symptoms of anxiety were better recalled by PD patients. Results are consistent with previous findings but are inexplicable by existing theories.
View details for Web of Science ID 000078674900014
View details for PubMedID 10067001
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Analysis of cardiovascular regulation.
Biomedical sciences instrumentation
1999; 35: 135-140
Abstract
Adequate characterization of hemodynamic and autonomic responses to physical and mental stress can elucidate underlying mechanisms of cardiovascular disease or anxiety disorders. We developed a physiological signal processing system for analysis of continuously recorded ECG, arterial blood pressure (BP), and respiratory signals using the programming language Matlab. Data collection devices are a 16-channel digital, physiological recorder (Vitaport), a finger arterial pressure transducer (Finapres), and a respiratory inductance plethysmograph (Respitrace). Besides the conventional analysis of the physiological channels, power spectral density and transfer functions of respiration, heart rate, and blood pressure variability are used to characterize respiratory sinus arrhythmia (RSA), 0.10-Hz BP oscillatory activity (Mayer-waves), and baroreflex sensitivity. The arterial pressure transducer waveforms permit noninvasive estimation of stroke volume, cardiac output, and systemic vascular resistance. Time trends in spectral composition of indices are assessed using complex demodulation. Transient dynamic changes of cardiovascular parameters at the onset of stress and recovery periods are quantified using a regression breakpoint model that optimizes piecewise linear curve fitting. Approximate entropy (ApEn) is computed to quantify the degree of chaos in heartbeat dynamics. Using our signal processing system we found distinct response patterns in subgroups of patients with coronary artery disease or anxiety disorders, which were related to specific pharmacological and behavioral factors.
View details for PubMedID 11143335
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Voluntary breath holding in panic and generalized anxiety disorders
PSYCHOSOMATIC MEDICINE
1998; 60 (6): 671-679
Abstract
Because breath holding causes arterial pCO2 to increase, we used it to test the hypothesis that in panic disorder (PD) a biological suffocation monitor is pathologically sensitive.Nineteen patients with PD, 17 with generalized anxiety disorder (GAD), and 22 normal controls took deep breaths on signal and held them until a release signal was given 30 seconds later. This was repeated 12 times separated by 60-second normal breathing periods.PD patients reported having had in the past more symptoms of shortness of breath when anxious, and more frequent frightening suffocation experiences than the other groups. However, increases in self-rated anxiety between periods of normal breathing and periods of breath holding were similar in all three groups. Skin conductance, blood pressure, and T-wave amplitude reactions to breath holdings were also similar, but heart rate acceleration upon taking a deep breath was greater in GAD patients. Before and after individual breath holdings, end-tidal pCO2 was lower in PD patients than in normal controls; GAD patients were intermediate. Inspiratory flow rate did not differ between groups.Our physiological results provide no direct support for an overly sensitive suffocation alarm system in PD. Lower pCO2 may be due to anxiety causing hyperventilation in patients prone to panic.
View details for Web of Science ID 000077189300003
View details for PubMedID 9847025
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Using minute ventilation for ambulatory estimation of additional heart rate
BIOLOGICAL PSYCHOLOGY
1998; 49 (1-2): 137-150
Abstract
Both physical activity and emotion produce physiological activation. The emotional component of heart rate (HR) can be estimated as the additional HR (aHR) above that predicted by O2 consumption. Our innovation was to substitute minute ventilation (V) for O2 consumption, calculating aHR from individual relations between V and HR during an exercise test. We physiologically monitored 28 flight phobics and 15 non-anxious controls while walking (leaving the hospital, entering a plane), and during a commercial flight. Raw HR did not differ between phobics and controls when leaving the hospital (118/114 bpm) or entering the plane (117/110 bpm). However, although aHR was not different when leaving the hospital (7.0/8.6 bpm), it was significantly greater when entering the plane (17.5/9.9 bpm), accurately reflecting the increased subjective anxiety of the phobics. V was not higher in phobics than controls during any condition, suggesting an absence of hyperventilation in the phobics. The results demonstrate the utility of our method for analyzing HR in people whose stress occurs when they are physically active.
View details for Web of Science ID 000076545300010
View details for PubMedID 9792490
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Taking the laboratory to the skies: Ambulatory assessment of self-report, autonomic, and respiratory responses in flying phobia
PSYCHOPHYSIOLOGY
1998; 35 (5): 596-606
Abstract
We evaluated the feasibility of recording multiple physiological anxiety measures during a flight and how well they could distinguish flight phobics from controls. Benefits of baseline adjustment and transformation for all variables and adjustment of heart rate by ventilation to give additional heart rate were calculated. Effect size, one measure of the power to discriminate groups, was between 1.1 and 1.7 for heart rate measures. Although respiratory rate and minute ventilation, indicators of hyperventilation, did not differ between groups, phobics paused more during inspiration than did controls. Phobics also showed more skin conductance fluctuations and less respiratory sinus arrhythmia. Self-reported anxiety was a more powerful discriminator than physiological measures, a result that may be partially explained by how phobics were selected. These results indicate that monitoring of multiple physiological systems outside the laboratory is practical and informative. Physiological measures of psychological importance can be quantified accurately in a noisy, changing, unsupervised ambulatory setting.
View details for Web of Science ID 000075303100012
View details for PubMedID 9715103
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Critique - Trusting computerized data reduction too much: A critique of Anderson's ambulatory respiratory monitor
BIOLOGICAL PSYCHOLOGY
1998; 49 (1-2): 215-219
View details for Web of Science ID 000076545300014
View details for PubMedID 9792494
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Autonomic instability during relaxation in panic disorder
PSYCHIATRY RESEARCH
1998; 80 (2): 155-164
Abstract
The ability to relax was assessed in 14 patients with panic disorder (PD) and 15 non-anxious control subjects for 10 min. Before and after relaxation, subjects performed a standardized activating task of talking continuously for 4 min. The fractional decline in reported anxiety, tension, and alertness between the first talking period and the relaxation minimum did not differ between groups, although absolute levels of anxiety and tension were higher for PD patients. The fractional decline in skin conductance between the first talking period and the last minute of relaxation was less for PD patients than control subjects, while their increase in skin temperature was greater. Skin conductance showed a linear decline over the logarithm of relaxation time, the slope of which was less steep for PD patients. Goodness of fit of skin conductance over log time was also significantly poorer for PD patients. Heart rate levels or slopes did not differ between groups. Autonomic differences between PD and control subjects were largely due to six patients who reported having panic attacks during the test and higher pretest anxiety levels. In conclusion, indicators of relaxation were inconsistent. Skin conductance suggested autonomic instability during quiet sitting in patients who panic or who are prone to panic.
View details for Web of Science ID 000075876300007
View details for PubMedID 9754695
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Personality, psychological states and heart rate in novice and expert parachutists
PERSONALITY AND INDIVIDUAL DIFFERENCES
1998; 25 (2): 365-380
View details for Web of Science ID 000075085700017
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Acute and delayed effects of alprazolam on flight phobics during exposure
VERHALTENSTHERAPIE
1998; 8 (1): 38-47
View details for Web of Science ID 000073032400004
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Don't worry and beware of white bears: Thought suppression in anxiety patients
JOURNAL OF ANXIETY DISORDERS
1998; 12 (1): 39-55
Abstract
The ability to suppress unwanted thoughts was investigated in patients with Generalized Anxiety Disorder (GAD; n = 29), Speech Phobics (n = 25), and nonanxious controls (n = 28). All participants spent 5 minutes thinking aloud about anything that came to mind while trying not to think of white bears. In another task, they thought aloud for 5 minutes while trying not to think of their main worry. Intrusions of unwanted thoughts were signaled by button presses and recorded on tape. In accordance with the disorder's definition and complaints of the GAD patients, they showed more intrusions of their main worry than of white bears. The opposite was true for other participants. Compared to a baseline measure, all participant groups were unable to reduce duration of main worry thoughts when trying to suppress them.
View details for Web of Science ID 000072619100003
View details for PubMedID 9549608
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Speech disturbances and gaze behavior during public speaking in subtypes of social phobia
16th National Conference of the Anxiety-Disorders-Association-of-America
PERGAMON-ELSEVIER SCIENCE LTD. 1997: 573–85
Abstract
Twenty-four social phobics with public speaking anxiety and 25 nonphobic individuals (controls) gave a speech in front of two people. Subjective anxiety, gaze behavior, and speech disturbances were assessed. Based on subjects' fear ratings of social situations, phobics and controls were divided into the generalized and nongeneralized subtype. Results showed that generalized phobics reported the most, and nongeneralized controls the least anxiety during public speaking. All subjects had longer and more frequent eye contact when delivering a speech than when talking with an experimenter or sitting in front of an audience. Phobics showed more filled pauses, had longer silent pauses, paused more frequently, and spent more time pausing than controls when giving a speech. Generalized phobics spent more time pausing during their speech than the other subgroups (nongeneralized controls, generalized controls, and nongeneralized phobics). These results suggest that generalized phobics tended to shift attentional resources from speech production to other cognitive tasks.
View details for Web of Science ID 000071540800002
View details for PubMedID 9455720
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Acute and delayed effects of alprazolam on flight phobics during exposure
BEHAVIOUR RESEARCH AND THERAPY
1997; 35 (9): 831-841
Abstract
In order to test if a benzodiazepine would enhance or hinder the therapeutic effects of exposure, immediate and delayed effects of alprazolam on flight phobics were assessed by questionnaires and ambulatory physiological recording. Physiological measures included heart rate, skin conductance level and fluctuations, finger temperature, respiratory sinus arrhythmia, and various respiratory measures derived from two bands calibrated for each subject. Twenty-eight women with flying phobia flew twice at a 1-week interval. One and a half hours before flight 1, 14 randomly assigned phobics received double-blind 1 mg of alprazolam and 14 received placebo. On flight 1, alprazolam reduced self-reported anxiety (5.0 vs 7.4) and symptoms (5.3 vs 3.6) more than placebo, but induced an increase in heart rate (114 vs 105 bpm) and respiratory rate (22.7 vs 18.3 breaths/min). Before flight 2, the alprazolam group did not expect to be more anxious than the placebo group (6.7 vs 6.5), but in fact indicated more anxiety during flight (8.5 vs 5.6), and a substantial increase in panic attacks from flight 1 to flight 2 (7% vs 71%). Heart rates in the alprazolam group increased further (123 bpm). Results indicate that alprazolam increases physiological activation under acute stress conditions and hinders therapeutic effects of exposure in flying phobia.
View details for Web of Science ID A1997XR87500005
View details for PubMedID 9299803
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Clinical characteristics of flight phobia
JOURNAL OF ANXIETY DISORDERS
1997; 11 (3): 241-261
Abstract
Sixty-six subjects with severe fear of flying were recruited by advertisement and compared to 21 controls without flying fears. Subjects were interviewed and given several questionnaires to determine DSM-III-R diagnoses, history of flying, and development and course of flying phobia. Our phobic sample had a mean age of 46 and was 89% female. Diagnostically, 27% met criteria for current Panic Disorder with Agoraphobia, and 17% criteria for that diagnosis in the past. These two groups were more concerned with internal or social anxiety stimuli during flight than the group who had never had panic attacks but met criteria for Simple Phobia (flying). All three groups were equally concerned about external dangers. Traumatic flight events were common in phobics and controls, but phobics reported reacting to these events more strongly. Our results suggest a vulnerability-stress model with several vulnerability factors, including cognitive ones. Treatment implications are discussed.
View details for Web of Science ID A1997XG50100002
View details for PubMedID 9220299
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Risperidone in the treatment of delusional parasitosis: A case report
JOURNAL OF CLINICAL PSYCHOPHARMACOLOGY
1997; 17 (2): 131-132
View details for Web of Science ID A1997WQ26500021
View details for PubMedID 10950485
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Automatic but not strategic processing is abnormal in schizophrenics
ELSEVIER SCIENCE BV. 1997: 233–33
View details for Web of Science ID A1997WP19600663
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N400 evidence of abnormal responses to speech in Alzheimer's disease
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1996; 99 (3): 235-246
Abstract
The status of semantic priming in Alzheimer's disease (AD) was examined using the speech elicited N400 component of the event-related brain potential (ERP). Speech was naturally paced, with 1 s of silence before the final word. In the semantic task, subjects attended to the meaning of the sentences for a subsequent memory test. In the phonemic monitoring task, they counted the words beginning with the letter 'p'. The effects of age were assessed by comparing young and elderly, and the effects of disease by comparing elderly and AD subjects. In healthy young and elderly subjects, N400s were large to semantically unprimed words and small to semantically primed words. In AD subjects, N400s were large to primed words, reflecting a failure of the sentence stem to prime the final word, and probably an impairment in semantic knowledge. The N400 priming effect was not smaller during the phonemic than semantic task in any group, suggesting that the semantic qualities of speech are processed even when subjects are attending to phonemic qualities. N400 latency was delayed with age and further delayed with dementia.
View details for Web of Science ID A1996VL66900004
View details for PubMedID 8862113
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Prepulse inhibition of ERP components elicited by startling noises
WILEY-BLACKWELL PUBLISHING, INC. 1996: S37–S37
View details for Web of Science ID A1996VF57700147
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Activation in novice and expert parachutists while jumping
PSYCHOPHYSIOLOGY
1996; 33 (1): 63-72
Abstract
Heart and respiration rates were measured ambulatorily in 16 novice and 25 expert (> 380 delayed free-fall jumps) sports parachutists while making a static-line jump. Self-reported anxiety and heart rate peaked near the point of jumping in both groups rather than earlier in experts, as reported by Fenz and Epstein (1967, Psychosomatic Medicine, 29, 33-51). While sitting in the airplane 1 min before exit, mean heart rate was 124 bpm in novices and 102 in experts and increased during jumping to 170 and 145, respectively. The almost identical rise in the two groups could be accounted for largely by physical exertion, replicated with jumps from a training model on the ground. Exercise testing at a different location showed that experts were more fit. Respiration rate was higher in the airplane than at baselines, especially for novices. In conclusion, our results are more compatible theoretically with extinction of anticipatory anxiety than with learned anxiety inhibition.
View details for Web of Science ID A1996TM04800007
View details for PubMedID 8570796
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Issues related to social anxiety among controls in social phobia research
BEHAVIOR THERAPY
1996; 27 (1): 79-91
View details for Web of Science ID A1996UG68900008
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SOCIAL PHOBIA WITH AND WITHOUT AVOIDANT PERSONALITY-DISORDER - PRELIMINARY BEHAVIOR-THERAPY OUTCOME FINDINGS
JOURNAL OF ANXIETY DISORDERS
1995; 9 (5): 427-438
View details for Web of Science ID A1995RR21600006
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SEMANTIC PRIMING IS DISRUPTED BY INTRUSIVE NOISES IN THE ELDERLY
WILEY-BLACKWELL PUBLISHING, INC. 1995: S32–S32
View details for Web of Science ID A1995RT16000128
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ELDERLY MEN AND WOMEN ARE LESS RESPONSIVE TO STARTLING NOISES - N1, P3 AND BLINK EVIDENCE
Annual Meeting of the Society-for-Psychophysiological-Research
ELSEVIER SCIENCE BV. 1995: 57–80
Abstract
Previously we observed that the P3 component of the event-related brain potential (ERP) elicited by startling noises, and to a lesser extent P3 to target tones, is reduced in the elderly (Ford & Pfefferbaum, 1991). In the current experiment, we tried to eliminate possible effects of age-related hearing deficits on the responses to noises by filtering them to include only frequencies heard best by the elderly (0-1000 Hz) and by setting noise intensity relative to each subject's threshold (sensation level, SL). Twelve younger (mean 22 years) and 12 older (mean 69 years) men and women listened to three sequences of tones (80%, 500 Hz, 70 dB SPL) and noises (20%). One type of noise occurred in each sequence (wide band noise set to 107 dB SPL, narrow band noise set to 107 dB SPL, or narrow band noise set to approximately 65 dB SL). The order of the three sequences was counterbalanced across age and sex. Younger subjects blinked to the noise 4-5 times more often than older subjects and had N1 and P3 amplitudes that were 2-3 times larger, regardless of the noise type. N1 amplitude to the background frequent tones and non-startle blinks did not differ between groups. Thus, even when noises were narrow band and set relative to each subject's threshold, older subjects were less responsive to startling auditory stimuli than were younger.
View details for Web of Science ID A1995QE66900001
View details for PubMedID 7734630
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PSYCHOPHYSIOLOGICAL DIFFERENCES BETWEEN SUBGROUPS OF SOCIAL PHOBIA
JOURNAL OF ABNORMAL PSYCHOLOGY
1995; 104 (1): 224-231
Abstract
Individuals meeting criteria of the revised third edition of Diagnostic and Statistical Manual for Mental Disorders (American Psychiatric Association, 1987) for social phobia with a fear of speaking in front of people were subdivided into those with (n = 16) and without (n = 14) avoidant personality disorder (APD). These individuals and nonanxious controls (n = 22) spoke in front of a small audience while speaking time, subjective anxiety, fearful thoughts, and electrocardiographic and respiratory measures were recorded. Controls spoke for longer than either social phobia group. Those with social phobia and APD reported more subjective anxiety and more fear cognitions than the other two groups; phobic individuals without APD showed greater heart rates in the phobic situation than either social phobics with APD or controls. The latter two groups did not differ in heart rate. These results indicate incongruent subjective and heart rate responses to the feared situation. A similar pattern of results was found when participants were divided into generalized and specific social phobia groups.
View details for Web of Science ID A1995QD42800025
View details for PubMedID 7897046
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ERPS FOR INFREQUENT OMISSIONS AND INCLUSIONS OF STIMULUS ELEMENTS
PSYCHOPHYSIOLOGY
1994; 31 (6): 544-552
Abstract
A negative event-related potential (ERP) wave called mismatch negativity (MMN) is elicited by an infrequent deviant stimulus in a sequence of frequent standard stimuli. Omission of a stimulus in a sequence of stimuli, however, has been considered to elicit a negativity different from MMN. The present study addressed this issue by examining ERPs for infrequent omissions and inclusions of compound stimuli or their elements. Three kinds of stimuli were presented: a 1000-Hz sine wave tone (Sine), white noise with the 1000-Hz frequency sharply filtered out (Noise), and a composite of the pure tone and the filtered white noise (SiNoise). All stimuli had 50 ms duration and were presented with a regular interstimulus interval of 650 ms. Intensities were 75 dB SPL for the tone and noise stimuli and slightly higher for the composite stimulus. The three kinds of stimuli were presented on separate runs, either as the frequent stimulus or one of two infrequent stimuli, each with 10% probability. Infrequent omission of the large stimulus element (Sine deviant to SiNoise) tended to elicit later MMN than inclusion of the same element (SiNoise deviant to Sine). Omission of the small stimulus element (Noise deviant to SiNoise) elicited a smaller and later MMN than did inclusion of the same element (SiNoise deviant to Noise). These data suggest that MMNs are also elicited by partial stimulus omissions, although they seem to be more sensitive to other kinds of stimulus deviances.
View details for Web of Science ID A1994PT66700003
View details for PubMedID 7846215
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CLINICAL CHARACTERISTICS OF DRIVING PHOBIA
JOURNAL OF ANXIETY DISORDERS
1994; 8 (4): 323-339
View details for Web of Science ID A1994PQ96000004
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ERPS IN SCHIZOPHRENIA - EFFECTS OF ANTIPSYCHOTIC MEDICATION
BIOLOGICAL PSYCHIATRY
1994; 36 (3): 153-170
Abstract
Thirty unmedicated schizophrenics were compared to 29 age-matched controls on auditory and visual event-related brain potential (ERP) paradigms. Twenty-one of these patients were tested again after 1 week on placebo and after 4 weeks on antipsychotic medication. Before treatment, N1, N2, and P3 components of the auditory ERP were smaller in the schizophrenics than in the controls. Although visual N2 was smaller in schizophrenics, visual P3 was not. In spite of significant clinical improvement with antipsychotic treatment, amplitudes of auditory and visual N1, N2, and P3 were not significantly changed. Higher blood levels of antipsychotic medication were related to reductions in auditory P3 latency, however. In addition, higher levels of cerebrospinal fluid (CSF) MHPG (methoxyhydroxyphenylglycol) were associated with larger auditory N1s and larger auditory and visual P3s, suggesting an influence of arousal on these components in schizophrenics. In spite of this influence, reduction of the auditory P3 in schizophrenia is an enduring trait of the disease, which is not affected by antipsychotic medication or clinical improvement.
View details for Web of Science ID A1994PB80100003
View details for PubMedID 7948453
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DOES BEHAVIORAL TREATMENT OF SOCIAL PHOBIA LEAD TO COGNITIVE CHANGES
BEHAVIOR THERAPY
1994; 25 (3): 503-517
View details for Web of Science ID A1994PR42900010
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ABNORMALITIES OF THE LEFT TEMPORAL-LOBE IN SCHIZOPHRENIA
NEW ENGLAND JOURNAL OF MEDICINE
1992; 327 (23): 1689-1689
View details for Web of Science ID A1992KA26000031
View details for PubMedID 1435914
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P3 AND SCHIZOPHRENIA
ANNALS OF THE NEW YORK ACADEMY OF SCIENCES
1992; 658: 146-162
View details for Web of Science ID A1992JL81200010
View details for PubMedID 1353949
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STRESS TEST REACTIVITY IN PANIC DISORDER
ARCHIVES OF GENERAL PSYCHIATRY
1992; 49 (4): 301-310
Abstract
The psychological and physiological reactivity of 52 patients with panic disorder to mental arithmetic, cold pressor, and 5% carbon dioxide inhalation tests was compared with that of 26 age- and sex-matched normal subjects. In general, patients with panic disorder were neither more physiologically reactive to these stressors than normal subjects nor slower to recover from them, but they were tonically more anxious and much more likely to ask to stop carbon dioxide inhalation or to report panic attacks during this test. Patients who reported panic attacks (46%) had manifested greater anticipatory anxiety before the gas was delivered, accompanied with increased beta-adrenergic cardiac tone. Thus, anticipatory anxiety can be an important factor in panic provocation. Physiological measures varied greatly in their sensitivity to phasic or tonic anxiety. Carbon dioxide stimulated large increases in respiratory minute volume, but these increases were no greater for patients than for normal subjects.
View details for Web of Science ID A1992HM91400006
View details for PubMedID 1558464
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IMIPRAMINE AND ALPRAZOLAM EFFECTS ON STRESS TEST REACTIVITY IN PANIC DISORDER
BIOLOGICAL PSYCHIATRY
1992; 31 (1): 35-51
Abstract
The reactivity of 40 panic disorder patients on mental arithmetic, cold pressor, and 5% CO2 inhalation stressors was tested before and after 8 weeks of treatment with imipramine, alprazolam, or placebo. Mean levels of subjective and physiological stress measures were compared during a baseline before any stressors were given, and at anticipation, stressor, and recovery periods for each stressor. After treatment, imipramine patients differed from the other two treatment groups on the prestressor baseline in showing higher systolic blood pressure (mean difference about 10 mmHg), higher diastolic blood pressure (10 mm Hg), higher heart rate (15 bpm), less respiratory sinus arrhythmia, shorter pulse transit time, and lower T-wave amplitude. Respiratory measures, electrodermal measures, body movement, and self-reported anxiety and excitement did not distinguish the groups. Reactivity to the stress tests was unaffected by the medications, but tonic differences present in the baseline persisted.
View details for Web of Science ID A1992GX47400004
View details for PubMedID 1543796
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PSYCHOPHYSIOLOGICAL ASSESSMENT OF DRIVING PHOBIA
JOURNAL OF PSYCHOPHYSIOLOGY
1992; 6 (4): 311-320
View details for Web of Science ID A1992KV73700003
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IS THERE P300 ASYMMETRY IN SCHIZOPHRENIA - REPLY
ARCHIVES OF GENERAL PSYCHIATRY
1991; 48 (4): 381-383
View details for Web of Science ID A1991FE95100015
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AUDITORY EVENT-RELATED POTENTIALS AND ELECTRODERMAL ACTIVITY IN MEDICATED AND UNMEDICATED SCHIZOPHRENICS
BIOLOGICAL PSYCHIATRY
1991; 29 (6): 585-599
Abstract
Event-related potentials (ERPs) and electrodermal activity were studied in 14 medicated schizophrenics, 17 unmedicated schizophrenics, and 23 age- and education-matched controls. Subjects were run in three auditory stimulus paradigms differing from the usual ERP paradigms in having interstimulus intervals greater than 12 sec to permit measurement of the longer latency skin conductance response (SCR). In every paradigm medicated but not unmedicated schizophrenics had smaller N120 amplitudes and fewer SCRs than controls. In addition, medicated schizophrenics showed reduced P200 amplitude and latency, longer P320 latency, and reduced skin conductance levels in certain paradigms. These effects cannot easily be attributed to different mental states of medicated and unmedicated patients, since their Brief Psychiatric Rating Scale scores were almost the same. It is more probable that antipsychotic and antiparkinsonian drugs reduced electrodermal activity through anticholinergic mechanisms and that the antipsychotic drugs attenuated N120 through other biological mechanisms.
View details for Web of Science ID A1991FG08800007
View details for PubMedID 1675890
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HOW BLIND ARE DOUBLE-BLIND STUDIES
JOURNAL OF CONSULTING AND CLINICAL PSYCHOLOGY
1991; 59 (1): 184-187
Abstract
Psychopharmacological studies usually attempt to eliminate "nonspecific" influences on outcome by double-blind designs. In a randomized, double-blind comparison of alprazolam, imipramine, and placebo, the great majority of panic disorder patients (N = 59) and their physicians were able to rate accurately whether active drug or placebo had been given. Moreover, physicians could distinguish between the two types of active drugs. Inasmuch as correct rating was possible halfway through treatment, concerns about the internal validity of the double-blind strategy arise.
View details for Web of Science ID A1991EV98700024
View details for PubMedID 2002136
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EFFECT OF 2 BETA-BLOCKERS ON STRESS DURING MENTAL ARITHMETIC
PSYCHOPHARMACOLOGY
1991; 105 (4): 573-577
Abstract
Heart rate, blood pressure, and subjective stress ratings were recorded from 36 healthy normotensive students at three points in time: during a drug-free baseline, during a baseline 2 h after ingesting single oral doses of atenolol (75 mg), metoprolol (150 mg), or lactate placebo, and during a subsequently administered mental arithmetic test. Both beta-blockers equally reduced baseline heart rate and heart rate response to arithmetic, but subjective stress rating increases to arithmetic were greater for atenolol than for placebo and metoprolol. These results are contrary to peripheral theories of anxiety regulation. While the hydrophilic atenolol barely penetrates the blood-brain barrier, the lipophilic metoprolol can exert direct CNS effects in addition to its peripheral actions. Central stress-dampening effects of lipophilic beta-blockers may override peripheral baroreceptor-mediated stress-promoting effects.
View details for Web of Science ID A1991GN10500022
View details for PubMedID 1771224
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FILTER FREQUENCY IN P-3 EXPERIMENTS
BIOLOGICAL PSYCHIATRY
1990; 28 (12): 1070-1071
View details for Web of Science ID A1990EP89400012
View details for PubMedID 2289003
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SKIN-CONDUCTANCE HABITUATION IN PANIC DISORDER PATIENTS
BIOLOGICAL PSYCHIATRY
1990; 27 (11): 1231-1243
Abstract
Skin conductance habituation was compared between 38 patients meeting DSM-III criteria for Panic Disorder and 29 normal controls. Approximately half of each group was randomly assigned to be given 100 dB SPL tones and the other half 75 dB tones. All indices pointed to slowed habituation in patients compared with normals: number of trials to response habituation, total number of responses, and slope of decline of skin conductance level. Patient-normal differences were not significantly larger for 100 dB than for 75 dB. In addition, patients compared with normals had more nonspecific fluctuations, higher skin conductance levels, and a shorter response latency to the first stimulus. Stepwise discriminant analyses classified patients and normals better in the 100 dB than in the 75 dB condition, and showed that the various skin conductancy variables were largely redundant at the higher intensity.
View details for Web of Science ID A1990DF72900007
View details for PubMedID 2191728
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CARDIOVASCULAR AND SYMPTOMATIC REDUCTION EFFECTS OF ALPRAZOLAM AND IMIPRAMINE IN PATIENTS WITH PANIC DISORDER - RESULTS OF A DOUBLE-BLIND, PLACEBO-CONTROLLED TRIAL
JOURNAL OF CLINICAL PSYCHOPHARMACOLOGY
1990; 10 (2): 112-118
Abstract
Seventy-nine patients with panic disorder were randomized to an 8-week double-blind treatment with alprazolam, imipramine, or placebo. Patients kept daily records of panic attacks, activity, anxiety, sleep, and medication use. Weekly measures of anxiety, depression, somatic symptoms, fears, avoidance, disability, and improvement were obtained. All patients underwent a symptom-limited exercise treadmill and other cardiovascular measures. By physician and patient global assessment, patients receiving alprazolam or imipramine were significantly better than patients on placebo. The alprazolam effects were apparent by week 1; the imipramine effects by week 4. All groups showed significant reductions in anxiety, depression, somatic measures, and panic attack frequency. At 8 weeks, patients in the alprazolam group reported significantly less fear than patients in the other two groups. Subjects in the imipramine group showed a significant increase in heart rate and blood pressure.
View details for Web of Science ID A1990CX84900006
View details for PubMedID 2187912
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MOTOR-ACTIVITY AND TONIC HEART-RATE IN PANIC DISORDER
PSYCHIATRY RESEARCH
1990; 32 (1): 45-53
Abstract
Motor activity and tonic heart rate were monitored in 62 drug-free panic disorder patients and 40 normal control subjects. Mean daily activity, mean waking heart rate controlled for activity, and mean sleeping heart rate were determined. Panic disorder patients without phobic avoidance showed higher activity than control subjects or patients with limited or extensive avoidance. Similarly, an "inverted U", relationship between trait anxiety and activity was observed. On the other hand, neither mean waking nor sleeping heart rate showed significant differences between patients and controls, suggesting that the differences previously reported in laboratory studies result from anticipatory anxiety.
View details for Web of Science ID A1990DC99700006
View details for PubMedID 2349312
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SURREPTITIOUS DRUG-USE BY PATIENTS IN A PANIC DISORDER STUDY
AMERICAN JOURNAL OF PSYCHIATRY
1990; 147 (4): 507-509
Abstract
In a double-blind, placebo-controlled trial comparing alprazolam and imipramine for panic disorder, serum analysis revealed that a substantial proportion of the patients took explicitly prohibited anxiolytic medication. Excluding these patients changed the results.
View details for Web of Science ID A1990CW81000023
View details for PubMedID 1969248
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GUTTMAN SCALING IN AGORAPHOBIA - CROSS-CULTURAL REPLICATION AND PREDICTION OF TREATMENT RESPONSE PATTERNS
BRITISH JOURNAL OF CLINICAL PSYCHOLOGY
1990; 29: 37-41
Abstract
The Fear and Avoidance Scales (FAS) is an 11-item questionnaire consisting of two subscales that measure features of agoraphobia and claustrophobia and that were demonstrated to be valid Guttman scales in a British clinical population. The purposes of the study reported here were to replicate the scale characteristics in the United States and to determine if improvement during treatment would follow the sequence predicted by the hierarchy implied in the scales. The FAS was given to 25 female agoraphobics before and after behavioural treatment. A principal components analysis replicated the agoraphobia and claustrophobia factors established in the British sample. Scalogram analyses showed that the Claustrophobia subscale of the FAS was a valid Guttman scale in the US sample whereas the Agoraphobia subscale yielded a high coefficient of reproducibility but a low coefficient of scalability. Treatment reduced the patients' fears and avoidances in the predicted sequence since for both scales the hierarchy of items remained unchanged following treatment.
View details for Web of Science ID A1990CP17400004
View details for PubMedID 2310869
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USE OF MEDICATION AND INVIVO EXPOSURE IN VOLUNTEERS FOR PANIC DISORDER RESEARCH
AMERICAN JOURNAL OF PSYCHIATRY
1989; 146 (11): 1423-1426
Abstract
A survey of 794 subjects volunteering for studies of panic disorder with or without phobic avoidance revealed that fewer than 15% had received imipramine and fewer than 15% had undergone in vivo exposure, although the majority had engaged in some form of counseling and had used benzodiazepines. Subjects with spontaneous panic attacks reported more avoidance than subjects with situational attacks. One-half of the subjects were unemployed. The authors recommend wider use of the available effective treatments for panic disorder and phobic avoidance.
View details for Web of Science ID A1989AX18500005
View details for PubMedID 2817112
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P-3 IN SCHIZOPHRENIA IS AFFECTED BY STIMULUS MODALITY, RESPONSE REQUIREMENTS, MEDICATION STATUS, AND NEGATIVE SYMPTOMS
ARCHIVES OF GENERAL PSYCHIATRY
1989; 46 (11): 1035-1044
Abstract
Eighteen schizophrenics who were not taking medication, 13 schizophrenics who were taking medication, and 37 age-matched controls were tested with event-related potential paradigms designed to elicit P3 response automatically or effortfully (ie, with a choice reaction time task). Electroencephalograms were recorded from the 19 standard 10-20 electrode sites. Compared with controls, both groups of schizophrenics had reduced P3 amplitudes for both effortful and automatic paradigms. P3 latencies were delayed relative to controls for the medication-taking schizophrenics in the effortful paradigms. Negative symptoms derived from the Brief Psychiatric Rating Scale within 1 week of event-related potential testing correlated negatively with both auditory and visual P3 amplitude in the subjects who were not taking medication. There was no evidence that P3 is smaller over left temporal electrode sites in schizophrenics, as has been reported by others. P3 amplitude reduction in schizophrenia is a robust psychobiological phenomenon that is present regardless of medication status or task demands.
View details for Web of Science ID A1989AY08200009
View details for PubMedID 2573328
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PLASMA-LIPID LEVELS IN PATIENTS WITH PANIC DISORDER OR AGORAPHOBIA
AMERICAN JOURNAL OF PSYCHIATRY
1989; 146 (7): 917-919
Abstract
Plasma lipids were measured in 102 subjects with panic disorder or agoraphobia. In women, but not men, a significantly higher than expected number of subjects had cholesterol values that exceeded the 75th percentile of national reference values for their sex and age.
View details for Web of Science ID A1989AD14300020
View details for PubMedID 2742017
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COGNITIVE ASPECTS OF PANIC ATTACKS - CONTENT, COURSE AND RELATIONSHIP TO LABORATORY STRESSORS
BRITISH JOURNAL OF PSYCHIATRY
1989; 155: 86-91
Abstract
Twenty patients with panic attacks and ten controls were given a standardised interview about thoughts occurring during times of anxiety or panic attacks. The interviewer was blind to the subject's diagnosis. The 20 panic patients underwent a psychophysiological test battery which included a cold pressor test, mental arithmetic task, and 5.5% CO2 inhalation. More patients than controls reported thoughts centered on fears of losing control and shame when anxious. Panic patients rated their thoughts as stronger and clearer than did controls and they had more difficulty excluding them from their minds. A feeling of anxiety preceded anxious thoughts in patients. This suggests that 'faulty cognitions' are not the initial event in a panic attack, although anxious thoughts may exacerbate or maintain them. Significant correlations were found between the intensity of anxiety-related thoughts in anticipation of mental arithmetic and changes in diastolic blood pressure and heart rate during mental arithmetic.
View details for Web of Science ID A1989AJ61700013
View details for PubMedID 2605437
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P3 AND (DE)ACTIVATION
BEHAVIORAL AND BRAIN SCIENCES
1988; 11 (3): 393-394
View details for Web of Science ID A1988Q445200018
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EVENT-RELATED POTENTIALS TO TIME-DEVIANT AND PITCH-DEVIANT TONES
PSYCHOPHYSIOLOGY
1988; 25 (3): 249-261
View details for Web of Science ID A1988N733300001
View details for PubMedID 3406326
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EVENT-RELATED POTENTIALS TO BREAKS IN SEQUENCES OF ALTERNATING PITCHES OR INTERSTIMULUS INTERVALS
PSYCHOPHYSIOLOGY
1988; 25 (3): 262-268
View details for Web of Science ID A1988N733300002
View details for PubMedID 3406327
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AUTONOMIC CHANGES AFTER TREATMENT OF AGORAPHOBIA WITH PANIC ATTACKS
PSYCHIATRY RESEARCH
1988; 24 (1): 95-107
Abstract
Twenty-three patients meeting DSM-III criteria for agoraphobia with panic attacks and 14 age-, race-, and sex-matched nonanxious controls were tested in the laboratory and on a test walk in a shopping mall. The patients were tested before and after about 15 weeks of treatment with placebo and exposure therapy, imipramine and exposure therapy, or imipramine and initial antiexposure instructions. Controls were tested twice at a similar interval, but without any treatment. On test day 1, patients compared to controls showed higher average heart rate and skin conductance levels and greater numbers of skin conductance fluctuations in the laboratory, and higher heart rates before and during the test walk. Between pretreatment and posttreatment tests, clinical ratings improved and skin conductance levels decreased in all treatment groups. Heart rate levels in the laboratory, on the other hand, decreased in patients on placebo and rose in patients on imipramine. Thus, imipramine compromises the usefulness of heart rate as a measure of emotional arousal. Higher pretreatment heart rates predicted greater clinical improvement.
View details for Web of Science ID A1988N420300012
View details for PubMedID 3393620
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MITRAL-VALVE PROLAPSE AND PANIC DISORDER - A REVIEW OF THEIR RELATIONSHIP
PSYCHOSOMATIC MEDICINE
1988; 50 (2): 93-113
Abstract
There has been considerable speculation about a possible relationship between panic disorder and mitral valve prolapse syndrome (MVP), although empirical results have been highly inconsistent. Some studies report low frequencies of 0-8%, others high frequencies of 24-35% "definite" MVP in panic patients (average across 17 studies: 18% of panic patients, 1% of normal controls). Elevated prevalences of MVP were also reported for generalized anxiety disorder, bipolar affective disorder, and anorexia nervosa. Studies of MVP patients generally failed to find elevated prevalence of panic compared to other cardiac patients or normal controls (averages across seven studies: 14%, 10%, and 8%, respectively). Inconsistent results may be due to widely different diagnostic criteria for MVP, low reliability of this diagnosis, inadequate control groups, "non-blind" ratings of panic or MVP, and sampling bias in both patient and control populations. These problems as well as the great variations in the published results preclude any final judgment. If there is concomitance between MVP and panic, it is small and primarily involves subjects with milder or reversible variants of MVP. At present it seems most justified, however, to assume co-morbidity in highly symptomatic individuals rather than a functional relationship.
View details for Web of Science ID A1988M721400001
View details for PubMedID 3287421
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ANXIETY INDUCED BY FALSE HEART-RATE FEEDBACK IN PATIENTS WITH PANIC DISORDER
BEHAVIOUR RESEARCH AND THERAPY
1988; 26 (1): 1-11
View details for Web of Science ID A1988L510500001
View details for PubMedID 3341996
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Selective Processing of Threat Cues in Subjects with Panic Attacks
COGNITION & EMOTION
1988; 2 (3): 201-219
View details for DOI 10.1080/02699938808410924
View details for Web of Science ID 000208965500004
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Treadmill exercise test and ambulatory measures in panic attacks.
American journal of cardiology
1987; 60 (18): 48J-52J
Abstract
Treadmill exercise test performance and ambulatory heart rate and activity patterns of 40 patients with panic attacks were compared with 20 age-matched controls (control group 1) and 20 nonexercising controls (control group 2). All patients underwent a symptom-limited exercise stress test. Panic attack patients and control group 1 wore an ambulatory heart rate/activity monitor for up to 3 days. Panic patients had a significantly higher heart rate at 4 and 6 METS than either control group. The max METS were 11.2 +/- 2.3, 13.5 +/- 2.3 and 11.2 +/- 1.8 for the panic attack patients and control groups 1 and 2, respectively. One panic patient had ischemia on the treadmill at 12 METS. Panic patients had a significantly higher standing heart rate than controls. Furthermore, 11 of 39 panic patients had tachycardia on standing compared with 3 of 40 controls. Panic attack patients had higher wake and sleep heart rates than control group 1, but the differences were not significant. These results are consistent with autonomic dysfunction in panic patients but may also be due to differences in physical conditioning. The treadmill can be useful for reassuring patients and for identifying the rare patient with ischemia on exercise.
View details for PubMedID 3425557
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PANIC ATTACKS IN THE NATURAL-ENVIRONMENT
JOURNAL OF NERVOUS AND MENTAL DISEASE
1987; 175 (9): 558-565
Abstract
Despite much recent research, there is still little systematic information about the phenomenology of panic attacks, and their possible causes remain obscure. We investigated panic attacks in the natural environment using an event sampling approach. Twenty-seven panic attack patients and 19 matched normal controls kept panic attack and self-exposure diaries for 6 days and wore an ambulatory heart rate/physical activity recorder for 3 days. Patients reported 175 attacks, generally of moderate severity. The most frequent symptoms were palpitations, dizziness/lightheadedness, dyspnea, nausea, sweating, and chest pain/discomfort. The results did not support the classification of panic attacks recently proposed by Sheehan and Sheehan, which requires three symptoms as a cutoff for panic attacks. Panic attacks classified by the patients as situational (i.e., occurring in feared situations) were more severe and occurred in situational contexts different from spontaneous attacks, but were otherwise phenomenologically similar. Heart rates did not change during spontaneous attacks and were only mildly elevated during situational attacks or during the 15 minutes preceding these attacks. These heart rate changes were interpretable as effects of anxiety, although physical activity showed a similar pattern of changes. Some normal control subjects reported on the panic diary primarily situational anxiety episodes that were phenomenologically similar to, albeit less severe than, the patients' episodes. Panic patients may sometimes fail to perceive environmental triggers for their attacks because many attacks classified as spontaneous occurred in classical "phobic" situations. Furthermore, the comparison of concurrent diary and retrospective interview and questionnaire descriptions showed that panic patients have a tendency toward retrospective exaggeration. Implications for the assessment, definition, and classification of panic attacks are discussed.
View details for Web of Science ID A1987K221300008
View details for PubMedID 3655782
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SERUM PHOSPHATE AND ANXIETY IN MAJOR DEPRESSION
PSYCHIATRY RESEARCH
1987; 22 (1): 29-36
Abstract
Serum inorganic phosphate was measured in 33 hospitalized patients with unipolar depression. As predicted, serum phosphate showed significant negative correlations with Minnesota Multiphasic Personality Inventory scales sensitive to anxiety (Psychasthenia: -0.33) and somatic concern (Hypochondriasis: -0.51). This is consistent with previous observations of relative hypophosphatemia in patients with panic disorder. Clinical consequences of relative hypophosphatemia and the possible roles of hyperventilation or elevated peripheral catecholamines as mediators of this effect are discussed.
View details for Web of Science ID A1987K306900004
View details for PubMedID 3659218
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Event-related potentials to deviations of pitch and of timing.
Electroencephalography and clinical neurophysiology. Supplement
1987; 40: 241-245
View details for PubMedID 3480129
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PANIC ATTACK ASSOCIATED WITH PERCEIVED HEART-RATE ACCELERATION - A CASE-REPORT
BEHAVIOR THERAPY
1987; 18 (1): 84-89
View details for Web of Science ID A1987F595400008
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PANIC-DISORDERED SUBJECTS PERCEPTIONS OF FILM - A REPERTORY GRID STUDY
PERCEPTUAL AND MOTOR SKILLS
1986; 63 (3): 1119-1128
Abstract
Clinical research into panic attacks over the past two decades has led to the hypothesis that panic-disordered subjects may have a lower threshold to separation anxiety than normals. This hypothesis was investigated by measuring panic-disordered and normal subjects' reactions to viewing a film of a potentially anxiety-provoking situation. The extent to which individuals construe film through identification with the narrative's characters was also examined. To gauge these reactions a repertory grid was administered to 11 subjects with a history of panic disorder and 12 controls after they had watched a half-hour episode from a feature film in which a divorced couple fight acrimoniously over custody of their 17-yr.-old daughter. Five elements were characters mentioned in the film and two were of 'self,' one in a secure and another in an insecure situation. Ten constructs were elicited by a triadic sorting procedure and four were supplied. Ratings of elements on all constructs were subjected to a principal components analysis (INGRID). While the construals of the two groups were essentially similar, there were differences between them in terms of the perceived salience of the film's characters. Panic-disordered subjects also construed themselves as more insecure than did the normals. The results affirm the use of the repertory grid in the study of panic disorder and in the analysis of the perception of filmed events.
View details for Web of Science ID A1986F647700019
View details for PubMedID 3808886
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AUTONOMIC CHARACTERISTICS OF AGORAPHOBIA WITH PANIC ATTACKS
BIOLOGICAL PSYCHIATRY
1986; 21 (12): 1133-1154
Abstract
We compared electrodermal and heart rate measures of autonomic activation between patients meeting DSM-III criteria for agoraphobia with panic attacks and controls in terms of tonic level, reactivity to various types of stimuli, recovery, habituation, and spontaneous variability. The most striking differences between groups in the laboratory were higher tonic levels of skin conductance and heart rate among patients. Patients' heart rates were also tonically elevated in a test situation outside the laboratory. Certain measures of habituation and spontaneous variability also differed between groups, but there were only weak and inconsistent differences in reactivity to, or recovery from, stimuli with diverse qualities of novelty, startlingness, intensity, or phobicity. The elevated activation levels may be signs of a chronic state or may be phobic responses to the testing situations. A minority of patients failed to show these elevated levels.
View details for Web of Science ID A1986D850400004
View details for PubMedID 3756263
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LACTATE INFUSIONS AND PANIC ATTACKS - DO PATIENTS AND CONTROLS RESPOND DIFFERENTLY
PSYCHIATRY RESEARCH
1986; 17 (4): 295-308
Abstract
Ten patients with panic disorder or agoraphobia with panic attacks and 10 normal controls received infusions of normal saline (placebo) and sodium lactate in a single-blind design. The time course of changes in the dependent variables was closely monitored, and expectancy biases and demand characteristics were minimized. Lactate increased self-reported anxiety and heart rate equally in patients and controls. The only variables showing statistically different responses between the groups were systolic and diastolic blood pressure. Overall, in both groups, the effects of lactate were quite similar to states of natural panic or anxiety for both self-report measures and heart rate. Patients had a tendency to endorse somatic symptoms indiscriminately. Our data do not support response to lactate as a biological marker of proneness to panic attacks.
View details for Web of Science ID A1986C200600006
View details for PubMedID 3714912
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AMBULATORY HEART-RATE CHANGES IN PATIENTS WITH PANIC ATTACKS
AMERICAN JOURNAL OF PSYCHIATRY
1986; 143 (4): 478-482
Abstract
Of 33 "panic" attacks reported by patients wearing an ambulatory solid-state heart rate/activity monitor for 6 days, 19 (58%) occurred at heart rates disproportionate to activity levels and different enough from surrounding heart rates to indicate a distinct physiologic state. Intense panic attacks with three or more symptoms were the most readily identified. ECG monitoring found the elevated heart rates to be sinus tachycardias. Heart rate elevation did not occur during anticipatory anxiety episodes. Ambulatory heart rate recordings confirm the presence of major physiologic changes during self-reported panic attacks.
View details for Web of Science ID A1986A725500010
View details for PubMedID 3953890
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Applications of cognitive ERPs in psychiatric patients.
Electroencephalography and clinical neurophysiology. Supplement
1986; 38: 419-438
View details for PubMedID 3466780
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BIOLOGICAL MODELS OF PANIC DISORDER AND AGORAPHOBIA - A REVIEW
BEHAVIOUR RESEARCH AND THERAPY
1986; 24 (5): 553-567
View details for Web of Science ID A1986D906000008
View details for PubMedID 3753383
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SODIUM LACTATE INFUSIONS AND PANIC ATTACKS - A REVIEW AND CRITIQUE
PSYCHOSOMATIC MEDICINE
1986; 48 (1-2): 23-57
Abstract
Response to sodium lactate infusions has been proposed as an experimental model and a biologic marker for panic attacks. Several authors have claimed that patients suffering from panic attacks, but not normal controls, "panic" in response to lactate. A careful review of methods and results of 13 studies, however, reveals serious methodologic problems, lack of specificity and sensitivity, and a failure to consider cognitive variables. When baseline differences are ruled out, the responses of patients and controls may not differ. So far, response to lactate cannot be interpreted as a model and marker for panic attacks and does not provide evidence for their underlying biologic distinctness from other types of anxiety. Known biologic mechanisms do not sufficiently explain the effects of lactate. Instead, an interaction of peripheral physiologic changes, past experience, environmental cues, and their appraisal as threatening or dangerous seems to be a more appropriate model.
View details for Web of Science ID A1986AYV7400002
View details for PubMedID 3511491
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PANIC AND ANXIETY - THEORY AND RESEARCH ON A NEW CLASSIFICATION OF PANIC ATTACKS
ZEITSCHRIFT FUR KLINISCHE PSYCHOLOGIE-FORSCHUNG UND PRAXIS
1986; 15 (4): 281-302
View details for Web of Science ID A1986E527600001
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AMBULATORY MONITORING OF PATIENTS WITH ANXIETY AND PANIC
CLINICAL NEUROPHARMACOLOGY
1986; 9: 37-39
View details for Web of Science ID A1986G254000015
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COMBINED PHARMACOLOGICAL AND BEHAVIORAL TREATMENT FOR AGORAPHOBIA
BEHAVIOUR RESEARCH AND THERAPY
1985; 23 (3): 325-335
View details for Web of Science ID A1985AHA9400011
View details for PubMedID 2860892
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CLINICAL-APPLICATION OF THE P3-COMPONENT OF EVENT-RELATED POTENTIALS .2. DEMENTIA, DEPRESSION AND SCHIZOPHRENIA
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1984; 59 (2): 104-124
Abstract
Patients with dementia, schizophrenia and depression were tested with analogous auditory and visual event-related potential (ERP) paradigms designed to elicit a large P3. The patient groups were compared to age normative predictions derived from a large control sample for a number of ERP and behavioral variables. The results were similar for the auditory and visual paradigms. P3 latency was prolonged two or more S.D.s beyond that predicted by age for less than one-half of the demented patients. This latency prolongation was significant for the group as a whole but would result in too many false negatives if used diagnostically for individuals. Furthermore, increased P3 latency was not specific, as the schizophrenic patients also had later P3s. The amplitude of P3 was reduced in the demented patients, but it was also smaller in other patient groups. The only variable which distinguished the demented patients from both controls and from the other patients was the single trial P3 latency/RT correlation. The demented patients, as a group, had significantly lower P3 latency/RT correlations, but this effect also was not sensitive enough to be diagnostic for individuals. The data from these two paradigms suggest that the P3 amplitude and latency abnormalities observed reflect a common, rather than a diagnostically specific deficit. This study is in contrast to some others which report much more sensitivity and specificity in the use of P3 latency in the diagnosis of dementia. Differences in task demands, patient samples and ERP analysis techniques might explain some of the discrepancy.
View details for Web of Science ID A1984SN71300002
View details for PubMedID 6200305
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INTENSITY AND TASK EFFECTS ON EVOKED PHYSIOLOGICAL-RESPONSES TO NOISE BURSTS
PSYCHOPHYSIOLOGY
1984; 21 (4): 466-481
View details for Web of Science ID A1984SY92200012
View details for PubMedID 6463180
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EFFECTS OF STIMULUS SEQUENCE ON P300 AND REACTION-TIME IN SCHIZOPHRENICS - A PRELIMINARY-REPORT
ANNALS OF THE NEW YORK ACADEMY OF SCIENCES
1984; 425 (JUN): 570-577
View details for Web of Science ID A1984TA47400060
View details for PubMedID 6588876
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ERPS AND PSYCHOPATHOLOGY .1. BEHAVIORAL PROCESS ISSUES
ANNALS OF THE NEW YORK ACADEMY OF SCIENCES
1984; 425 (JUN): 496-522
Abstract
The clinical study of ERPs has an inherent defect--a self-selection of clinical populations that hampers equating of clinically defined groups on factors extraneous to the independent variables. Such ex post facto studies increase the likelihood of confounding variables in the interpretation of findings. Hence, the development of lawful relationships between clinical variables and ERPs is impeded and the fulfillment of description, explanation, prediction, and control in brain science is thwarted. Proper methodologies and theory development can increase the likelihood of establishing these lawful relationships. One methodology of potential value in the clinical application of ERPs, particularly in studies of aging, is that of divided attention. Two promising theoretical developments in the understanding of brain functioning and aging are the distraction-arousal hypothesis and the controlled-automatic attention model. The evaluation of ERPs in the study of brain-behavior relations in clinical populations might be facilitated by the differentiation of concurrent, predictive, content, and construct validities.
View details for Web of Science ID A1984TA47400054
View details for PubMedID 6588871
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CLINICAL-APPLICATION OF THE P3 COMPONENT OF EVENT-RELATED POTENTIALS .1. NORMAL AGING
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1984; 59 (2): 85-103
Abstract
Normal adult volunteer subjects ranging in age from 18 to 90 years participated in a study in which analogous auditory and visual paradigms, with infrequently occurring target and non-target events, were used to elicit event-related potentials (ERPs) with a prominent P3 component. Of the 135 subjects participating, 66 completed both auditory and visual paradigms. The amplitude and latency of P3 were analyzed using average ERPs, single trials (adaptive filter) and principal components analysis (PCA). Age regressions were calculated using measures derived from average ERPs and single trials. Single trial measures were better than average ERP measures in demonstrating age-related changes in P3 latency. There was a significant increase in P3 latency with age of 1-1.5 msec/year. The range of normal P3 latency for a given age (1 S.E. of the regression = 40 msec for the visual target stimuli) was much larger than obtained by other investigators. The visual paradigm produced higher P3 latency/age correlations than the auditory paradigm (visual target r = 0.52, non-target r = 0.42; auditory target r = 0.32, non-target r = 0.33). Within individuals, the amplitude and latency of P3 generated by auditory and visual stimuli were highly correlated, though the visual paradigm produced larger and later P3s than the auditory paradigm. There is an apparent change in the scalp topography of P3 with age. In young adults, P3s to target stimuli have a markedly parietal distribution. The distribution of P3 becomes more uniformly distributed from Pz to Fz with age. This may be due to changes in overlapping components such as the slow wave (SW) rather than to changes in the amplitude of P3 per se.
View details for Web of Science ID A1984SN71300001
View details for PubMedID 6200311
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BRAIN-STEM POTENTIALS IN CHRONIC-ALCOHOLICS
SOC PSYCHOPHYSIOL RES. 1982: 583–84
View details for Web of Science ID A1982PE85700148
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AUDITORY STIMULUS-INTENSITY EFFECTS ON COMPONENTS OF THE LATE POSITIVE COMPLEX
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1982; 54 (2): 132-146
View details for Web of Science ID A1982PG43000004
View details for PubMedID 6179738
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AUDITORY EVENT-RELATED POTENTIALS IN SCHIZOPHRENIA AND DEPRESSION
PSYCHIATRY RESEARCH
1981; 4 (2): 199-212
Abstract
Event-related potentials in two auditory target detection paradigms and two auditory paradigms without overt tasks were studied in 22 schizophrenic, 21 depressed, and 28 matched control subjects meeting Research Diagnostic Criteria. In the target detection paradigms, schizophrenics showed a pattern of reduced N120 amplitude and shorter P200 latency to frequently occurring tones, and reduced P300 and Slow Wave amplitude to infrequent target and nontarget tones. This pattern is consistent with impaired selective attention for stimuli. For depressed patients these variables were generally intermediate between those of schizophrenics and controls. In the other paradigms N120 latency was greater for schizophrenics, and P200 amplitude was less for depressed patients.
View details for Web of Science ID A1981LM54300009
View details for PubMedID 6939010
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P3 REDUCTION IN AUDITORY EVOKED-POTENTIALS OF SCHIZOPHRENICS
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1980; 49 (5-6): 497-505
Abstract
Fifteen schizophrenics and 15 age-matched controls performed a reaction time (RT) task. A Bernoulli sequence of 85 dB SPL, 50 msec, 800 c/sec (P = 0.85) and 1200 c/sec (P = 0.15) tones was presented with an interstimulus interval of 1 sec. Subjects were instructed to press a button quickly upon hearing the 1200 c/sec tone. If a subject failed to respond within 650 msec, a 50 msec white noise burst occurred. In averages synchronized with target tones and computed without respect to RT, P3 was maximal at PZ with a mean latency of 330 msec for both schizophrenics and controls. P3 amplitude at PZ, however, averaged 6 muV in schizophrenics and 14 muV in controls (P < 0.001). Both mean RT and mean within-subject variance were greater in schizophrenices than controls. Other kinds of averages were computed to investigate the possibility that the amplitude differences were associated with different RTs or with differences in P3 latency variability in underlying trails. Averages of trials associated with short RTs (100--286 msec) had larger P3s than averages associated with long RTs (287--600 msec) (P < 0.01). Within each RT range, however, schizophrenic P3s were smaller than control P3s. Neither response-synchronized averaging nor adaptive filtering eliminated P3 amplitude differences between groups, indicating that P3 latency variability cannot account for these differences. We hypothesize that the smaller P3s in schizophrenics represent a deficit in reactivity to unexpected stimuli that is compatible with normal RT performance.
View details for Web of Science ID A1980KH37100007
View details for PubMedID 6158431
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The relationship between autonomic variables and P300 in a habituation paradigm.
Progress in brain research
1980; 54: 422-426
View details for PubMedID 7220945
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SENSITIVITY OF SOME HUMAN COGNITIVE FUNCTIONS TO EFFECTS OF METHAMPHETAMINE AND SECOBARBITAL
DRUG AND ALCOHOL DEPENDENCE
1980; 5 (2): 145-150
Abstract
Sternberg's memory scanning task, Buschke's selective reminding task, and a time production task were given to 18 male subjects after they had received 10 mg of methamphetamine, 100 mg of secobarbital and placebo on separate days. Time production and learning that involved storage and retrieval of information in long-term memory were most sensitive to drug effects. Other measures of learning and memory scanning performance were not affected by either drug.
View details for Web of Science ID A1980JB29400007
View details for PubMedID 7353472
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AUDITORY BRAIN-STEM AND CORTICAL EVOKED-POTENTIALS IN SCHIZOPHRENIA
BIOLOGICAL PSYCHIATRY
1980; 15 (2): 209-223
Abstract
Auditory brain stem and cortical evoked potentials were recorded from 15 schizophrenics and 15 controls. There were significant cortical evoked potential differences between the two groups. However, brain stem evoked potentials were almost identical, suggesting that the cortical evoked potential differences are not due to peripheral factors such as inability to match sensory thresholds or defects in auditory acuity.
View details for Web of Science ID A1980JK81900003
View details for PubMedID 7417612
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Acute and chronic effects of ethanol on event-related potentials.
Advances in experimental medicine and biology
1980; 126: 625-639
View details for PubMedID 7405699
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Clinical application of sustained auditory evoked potentials.
Progress in brain research
1980; 54: 526-530
View details for PubMedID 7220963
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P300 and reaction time in schizophrenics and controls.
Progress in brain research
1980; 54: 522-525
View details for PubMedID 7220962
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Effects of stimulus intensity on P300.
Progress in brain research
1980; 54: 296-300
View details for PubMedID 7220929
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AGE-RELATED-CHANGES IN AUDITORY EVENT-RELATED POTENTIALS
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1980; 49 (3-4): 266-276
Abstract
Twelve elderly and 12 young women were subjects in a reaction-time task designed to elicit middle and late event-related potentials (ERP). The aged subjects differed from the young in respect to the later occurring ERP components: P2 was larger and later; P3 was later and had a different scalp distribution; the slow wave (SW) was smaller. In contrast, no age-related differences were found for N1 amplitude or latency. It is suggested that the diminution in SW amplitude contributes to the change in scalp distribution of P3 amplitude seen with age. The relationship of reaction time and P3 latency of single trials was examined by the adaptive filter technique. There was no difference between the old and young subjects as both groups revealed signficant, positive P3 latency-reaction time correlations.
View details for Web of Science ID A1980KD59600006
View details for PubMedID 6158403
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AGE-DIFFERENCES IN P3-REACTION TIME ASSOCIATIONS
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1980; 49 (3-4): 257-265
Abstract
Eight healthy old and 12 healthy young women had event-related potentials (ERPs) recorded during the performance of a memory retrieval task. For each subject the single trial data recorded at Pz were analyzed using Woody's adaptive filter technique. The old subjects differed from the young in several respects: P3 amplitude at Pz was smaller, P3 latency and reaction time (RT) were greater, the relationship between P3 latency and RT was considerably altered. The adaptive filter increased the amplitude of P3 but the age-related amplitude difference persisted, suggesting that this difference is not due to increased latency variability with age. The old subjects had lower single trial P3-RT correlations and longer elapsed time from P3 peak to the response than did the young subjects. Both groups had greater RTs for outset items ('negative' responses) than for inset items ('positive' responses). For the young subjects P3 latency was also greater for the outset compared to the inset items but the difference was not found for the old subjects. Thus, the relationship between P3 latency and RT is altered in the aged--P3 and RT are less tightly coupled than in the young.
View details for Web of Science ID A1980KD59600005
View details for PubMedID 6158402
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EVENT-RELATED POTENTIALS IN SCHIZOPHRENICS
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1980; 48 (2): 127-139
Abstract
Fifteen schizophrenics and 15 age-matched controls were compared on 3 auditory event-related potential (ERP) paradigms that elicited a variety of components. In one paradigm, tones were given at 0.75, 2.25 and 6.75 sec interstimulus intervals; in another, infrequently occurring targets in a reaction-time task were interspersed with frequent background stimuli; and, in a third, noise bursts or tones were delivered in a random sequence at either 70 or 100 dB SPL. The sensitivity of some of the ERP components in distinguishing schizophrenics from controls depended on the conditions under which the component was elicited. N1 amplitude was smaller in the schizophrenics than in the controls after longer interstimulus intervals. P2 amplitude was smaller in the schizophrenics than in the controls after longer interstimulus intervals. P2 amplitude was smaller in the schizophrenics only at higher stimulus intensities. P2 latency was shorter in schizophrenics except in the paradigm that varied interstimulus intervals. P3 amplitude, however, was much smaller in schizophrenics than controls ragardless of whether P3 was elicited by targets in a task or was elicited by 100 dB SPL stimuli. The loud stimuli also elicited blink reflexes that coincided with N1, but these reflexes did not vary by clinical group. Neither the amplitude of the slow wave following targets nor the sustained potential that accompanies prolonged auditory stimuli differed between schizophrenics and controls.
View details for Web of Science ID A1980JE94500002
View details for PubMedID 6153330
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State-trait considerations of event-related potential markers of psychopathology.
Psychopharmacology bulletin
1979; 15 (1): 36-39
View details for PubMedID 419247
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EVENT-RELATED POTENTIALS RECORDED FROM YOUNG AND OLD ADULTS DURING A MEMORY RETRIEVAL TASK
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1979; 47 (4): 450-459
Abstract
Six healthy old and 8 healthy young subjects each received a series of trials in a memory retrieval task devised by Sternberg (1966). On each trials, the subject received a memory set of 1-4 digits and was then shown a test digit. The subject's task was to press one of two response buttons indicating whether the test digit was a member of the memory set for that trial. Response time (RT) was found to be an increasing, linear function of the number of items held in memory. The slope of the RT function was a composite measure of the time necessary to process each additional item in memory while the intercept was a measure of stimulus encoding and response processes that do not depend on memory set size (see Sternberg 1966, 1969, 1975). We found that the latency of P3 to the test stimulus also increased with increases in memory set size, although the slope of the P3 was less than that for RT. We have suggested that the intercept of the P3 slope reflects the time it takes to encode the test stimulus before the evaluation of the stimulus starts, while the slope reflects the amount of time per digit needed to evaluate the set. We have suggested that the difference between RT and P3 slopes represents the additional time per digit which the subjects waits before making a response, due to low confidence occurring with more difficult task conditions (i.e., when set size = 4). We further suggest that the intercept of the RT-P3 latency slope is a reflection of pure response processes. Time estimates of these processes are made for young and old subjects.
View details for Web of Science ID A1979HQ18000008
View details for PubMedID 89949
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EVENT-RELATED POTENTIAL CHANGES IN HEALTHY AGED FEMALES
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1979; 46 (1): 81-86
Abstract
Neurophysiological changes in the central nervous system were demonstrated with EEG even-related potentials in healthy, aged women. Compared to young women, the aged women showed decreased amplitude of the late sustained potential (SP), increased P2 latency, disruption of the normal stimulus intensity-response amplitude function of P2 and increased amplitude of the P1 component. These age-related changes are interpreted as neurophysiological reflections of CNS deterioration found in non-senile elderly persons.
View details for Web of Science ID A1979GD90100009
View details for PubMedID 88334
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EVENT-RELATED POTENTIAL CHANGES IN CHRONIC-ALCOHOLICS
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1979; 47 (6): 637-647
Abstract
Ten chronic alcoholics (10+ year alcoholic drinking history) and ten age and sex matched controls were tested on an ERP paradigm which elicited a large P3 component. The N1 and P2 sensory evoked potential components did not differ in amplitude or latency between the two groups. The latency of the P3 was significantly longer for the alcoholics than the controls for both a response and non-response stimulus. This finding is consistent with the results seen in a variety of dementias and is offered as evidence of the dementing effects of prolonged alcoholism in this group of subjects. While the P3 latencies were prolonged for the alcoholics, their reaction times were not different from the controls. Single trial analysis using Woody's adaptive filter also demonstrated that the single trial estimates for the 3 latency were significantly prolonged for the alcoholics. The single trial correlation between the P3 latency and each trial's corresponding reaction time was significantly greater for the alcoholics than for the controls.
View details for Web of Science ID A1979HY33700001
View details for PubMedID 91494
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EFFECTS OF ETHANOL AND MEPERIDINE ON AUDITORY EVOKED-POTENTIALS
DRUG AND ALCOHOL DEPENDENCE
1979; 4 (5): 371-380
Abstract
The effects of ethanol and meperidine on the auditory evoked potential (AEP) to stimuli of different intensities were investigated. Sixteen normal male volunteers received ethanol, 0.8 ml/kg, 100 mg meperidine, and a placebo on different days in a double-blind study. AEPs were recorded from Fz, Cz and Pz electrode placements. The stimuli were 500 msec 1000 Hz tones at 50, 60, 70 and 80 dB sound pressure level presented in a pseudo-random sequence. Meperidine had no significant effect on AEP variables. Ethanol reduced AEP activity between 24 and 250 msec but had no effect on the sustained potential measured between 300 and 450 msec.
View details for Web of Science ID A1979GY68200001
View details for PubMedID 510179
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AGE EFFECTS ON EVENT-RELATED POTENTIALS IN A SELECTIVE ATTENTION TASK
JOURNALS OF GERONTOLOGY
1979; 34 (3): 388-395
Abstract
We used an event-related brain potential (ERP) technique developed by Hillyard et al. (1973) to test abilities to attenuate irrelevant stimuli and to detect target stimuli. Subjects, 12 healthy old (80.3 years) and 12 healthy young adults (22.0 years), heard 1500 Hz tones in one ear and 800 Hz tones in the other ear. Infrequently, the pitch of either tone was raised. During one run, infrequent tones in the right ear were targets, and in the other run those in the left ear were targets. Subjects counted targets. For both groups, an early component of the ERP (N1) was larger to tones in the attended ear than in the unattended ear, and a later component (P3) was largest to the target. This suggests that both groups can attenuate irrelevant stimuli and can use stimulus probability information in this task. That P3 was later for old subjects suggests that they take longer to decide stimulus relevance.
View details for Web of Science ID A1979GU67100010
View details for PubMedID 429773
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MARIHUANA EFFECTS ON ASSOCIATIONS TO NOVEL STIMULI
JOURNAL OF NERVOUS AND MENTAL DISEASE
1978; 166 (5): 362-364
Abstract
Sixteen college-educated male subjects were given an object description task during placebo conditions and while intoxicated with marijuana extract cookies calibrated to 0.3 mg/kg delta-9-tetrahydrocannabinol, a dose within the range of usual social use. The task was scored for fluency, flexibility, elaboration, and uniqueness, all of which represent associational thinking and are considered to be components of creativity. Marijuana did not enhance any of these measures.
View details for Web of Science ID A1978FA84600008
View details for PubMedID 650201
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PSYCHOPHYSIOLOGICAL CORRELATES OF PRACTICE OF TANTRIC YOGA MEDITATION
ARCHIVES OF GENERAL PSYCHIATRY
1978; 35 (5): 571-577
Abstract
Autonomic and electroencephalographic (EEG) correlates of Tantric Yoga meditation were studied in three groups of subjects as they progressed from normal consciousness into meditation. Groups differed in their level of meditation proficiency. Measures of skin resistance, heart rate, respiration, autonomic orienting responses, resting EEG, EEG alpha and theta frequencies, sleep-scored EEG, averaged evoked responses, and subjective experience were employed. Unlike most previously reported meditation studies, proficient meditators demonstrated increased autonomic activation during meditation while unexperienced meditators demonstrated autonomic relaxation. During meditation, proficient meditators demonstrated increased alpha and theta power, minimal evidence of EEG-defined sleep, and decreased autonomic orienting to external stimulation. An episode of sudden autonomic activation was observed that was characterized by the meditator as an approach to the Yogic ecstatic state of intense concentration. These findings challenge the current "relaxation" model of meditative states.
View details for Web of Science ID A1978EZ75200004
View details for PubMedID 365124
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METHAMPHETAMINE AND DIPHENHYDRAMINE EFFECTS ON RATE OF COGNITIVE PROCESSING
PSYCHOPHARMACOLOGY
1978; 59 (1): 13-19
Abstract
Three cognitive tasks in which performance depends primarily on the rate of cognitive processing were given to 24 male subjects before and after oral doses of methamphetamine (10 mg), diphenhydramine hydrochloride (100 mg), and placebo. Each subject was tested on Monday, Wednesday, and Friday of one week with drug orders balanced across subjects. Compared with placebo and diphenhydramine, methamphetamine increased the rate at which a visual display was scanned for a target stimulus. Methamphetamine affected neither a time-production task nor a divided attention task that required the subject to perform two cognitive tasks in a limited amount of time. This suggests that methamphetamine can increase cognitive processing speed on tasks involving familiar cognitive operations but that an increase is not likely in tasks involving more complicated decision processes. Compared with placebo and methamphetamine, diphenhydramine caused subjects no experience geophysical time as passing more slowly, but the drug had no significant effects on the visual search or divided-attention tasks. This suggests that time perception is more likely to be altered by diphenhydramine than is performance on tasks requiring short periods of rapid cognitive processing.
View details for Web of Science ID A1978FR58000003
View details for PubMedID 100808
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TIMING OF CNV RESOLUTION IN A MEMORY RETRIEVAL TASK
BIOLOGICAL PSYCHOLOGY
1978; 6 (1): 39-49
Abstract
Twelve men performed the Sternberg memory retrieval task while the EEG and EOG were recorded. Subjects saw a target set of 1 to 4 digits followed by a warning tone that was followed after 1.5 sec by a probe digit. Subjects indicated by pressing one of two levers whether the probe digit was in or out of the target set. The timing of contingent negative variation (CNV) resolution was measured as the latency of 50% resolution in stimulus-synchronized waveforms (SSWs), response-synchronized waveforms (RSWs), and model waveforms (MWs). The MWs were constructed by adding each RSW to itself using time displacements derived from the reaction times of the single trials of which the RSW was an average. The results indicated that CNV resolution is related to the timing of the motor response. MWs had resolution latencies close to those of the SSWs. In SSWs the N1 and P3 to the warning tone also varied with target set size.
View details for Web of Science ID A1978EJ88900004
View details for PubMedID 623857
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TIME COURSE EFFECTS OF MARIHUANA AND ETHANOL ON EVENT-RELATED POTENTIALS
PSYCHOPHARMACOLOGY
1978; 56 (1): 15-20
Abstract
Twelve male college students received orally on different days NIMH marijuana extract calibrated to contain 0.7 mg/kg delta-9-tetrahydrocannabinol, 1.0 ml/kg 95% ethanol, and placebo in a double-blind balanced-order design. The contingent negative variation (CNV), auditory evoked potential (EP), heart rate (HR), and subjective measures of intoxication were recorded prior to drug ingestion and at regular intervals for 4.5 h postdrug. Both drugs produced significant subjective effects. Marijuana increased HR but did not have a significant effect on CNV amplitude or EP peak amplitudes and latencies. Ethanol increased HR, but not significantly, and reduced CNV amplitude and N1-P2 amplitude. Time-action curves for ethanol's effect on subjective high, HR, and N1-P2 amplitude were parallel, peaking between 0.5 and 1.5 h postdrug and returning to baseline by the end of testing. Time-action curve for ethanol's effect on the CNV showed continuing amplitude reduction throughout the test session.
View details for Web of Science ID A1978EL13300003
View details for PubMedID 415321
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SLOWING OF SHORT-TERM-MEMORY SCANNING IN ALCOHOLICS
JOURNAL OF STUDIES ON ALCOHOL
1978; 39 (11): 1908-1915
Abstract
Hospitalized alcoholics taking disulfiram were found to process information in short-term memory at a slower rate than hospitalized controls, although short-term memory capacity was similar in the two groups.
View details for Web of Science ID A1978GF66500007
View details for PubMedID 739771
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LONG-LATENCY EVOKED-POTENTIALS AND REACTION-TIME
PSYCHOPHYSIOLOGY
1978; 15 (1): 17-23
View details for Web of Science ID A1978EK13400003
View details for PubMedID 625519
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CORTICAL SLOW POTENTIALS AND OCCIPITAL EEG IN CONGENITAL BLINDNESS
JOURNAL OF THE NEUROLOGICAL SCIENCES
1978; 37 (1-2): 51-58
Abstract
In a group of 7 congenitally blind adults, electroencephalographic occipital alpha rhythms were absent, but slow negative cortical potentials (CNV) were recorded over the visual cortex and were similar to those of normally sighted controls. Frontal and central CNV amplitudes, but not auditory evoked potentials or reaction times, were decreased significantly in the blind. The results confirm the presence of a developmental EEG abnormality following early blindness, and demonstrate the independance of slow potential generation from rhythmic 8--12 c/sec EEG activity in deafferented visual cortex. Non-sensory specific, event-related potentials such as the Contingent Negative Variation may prove to be useful psychophysiological probes of residual cortical function in brain regions which are deprived of primary sensory input.
View details for Web of Science ID A1978FJ17500004
View details for PubMedID 690664
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MARIHUANA AND MEMORY INTRUSIONS
JOURNAL OF NERVOUS AND MENTAL DISEASE
1977; 165 (6): 381-386
Abstract
Sixteen college-educated male subjects were tested on free-recall lists during intoxication with marijuana extract calibrated to 0.3 mg/kg delta-9-tetrahydrocannabinol and during placebo conditions. On each testing day subjects studied six lists using a regular overt rehearsal procedure and six lists using an association-overt rehearsal procedure in which they were to rehearse alound both list items and associations to those items. Both marijuana and the association-rehearsal procedure reduced the number of correct recalls and increased the number of intrusions (nonlist items which were incorrectly recalled as having been on the list to be learned). The intrusions were divided into three categories: a) words found on prior lists; b) associates spoken during the rehearsal; or c) totally new works not previously mentioned. Marijuana significantly increased the number of new intrusions; the association-rehearsal procedure did not. This result suggests that one of the effects of marijuana on cognitive functions in humans is to increase the number of intrusive thoughts and this may be the mechanism involved in some of the thought disorder observed with marijuana intoxication.
View details for Web of Science ID A1977EF05800003
View details for PubMedID 591936
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LATE EVENT-RELATED POTENTIALS AND PSYCHOPATHOLOGY
SCHIZOPHRENIA BULLETIN
1977; 3 (1): 105-120
View details for Web of Science ID A1977DG08500010
View details for PubMedID 325639
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MARIHUANA EFFECTS ON LONG-TERM-MEMORY ASSESSMENT AND RETRIEVAL
PSYCHOPHARMACOLOGY
1977; 52 (3): 239-241
Abstract
The ability of 16 college-educated male subjects to recall from long-term memory a series of common facts was tested during intoxication with marijuana extract calibrated to 0.3 mg/kg delta-9-tetrahydrocannabinol and during placebo conditions. The subjects' ability to assess their memory capabilities was then determined by measuring how certain they were about the accuracy of their recall performance and by having them predict their performance on a subsequent recognition test involving the same recall items. Marijuana had no effect on recall or recognition performance. These results do not support the view that marijuana provides access to facts in long-term storage which are inaccessible during non-intoxication. During both marijuana and placebo conditions, subjects could accurately predict their recognition memory performance. Hence, marijuana did not alter the subjects' ability to accurately assess what information resides in long-term memory even though they did not have complete access to that information.
View details for Web of Science ID A1977DH01300005
View details for PubMedID 406626
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ETHANOL AND MARIHUANA EFFECTS ON EVENT-RELATED POTENTIALS IN A MEMORY RETRIEVAL PARADIGM
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1977; 42 (3): 381-388
Abstract
Twelve men performed the Sternberg memory retrieval task under three experimental conditions: after oral doses of marihuana extract calibrated to contain 0.7 mg/kg delta9-tetrahydrocannabinol (THC), 1.0 ml/kg 95% ethanol, or placebo. Simultaneously, the EEG was recorded from Ca to linked ears and the EOG from leads above and below the right eye. In this task, subjects saw a set of 1 to 4 digits follwed by a warning tone that was followed 1.5 sec later by a test digit. Subjects indicated by pressing one of two buttons whether the test digit was in-set or out-of-the-set. There were no drug effects on N1 in the evoked potential to the warning tone, but P3 amplitude was smaller under THC and ethanol than under placebo. CNV amplitude in the interval between the warning tone and the test digit showed no drug effects, indicating that the subject was equally prepared for the test digit regardless of drug received. However, the latency of 50% resolution of the CNV was longer under THC than under placebo. THC also increased the reaction time for each set size by about 75 msec above the values for ethanol and placebo, the latter two not differing significantly. Set size affected N1 and P3 amplitudes and latencies and CNV amplitude, as well as 50% CNV resolution latency and reaction time, but there were no drug chi set size interactions.
View details for Web of Science ID A1977CY78100008
View details for PubMedID 65273
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DO COGNITIVE-ABILITIES DECLINE WITH AGE
GERIATRICS
1977; 32 (9): 59-62
View details for Web of Science ID A1977DU27500006
View details for PubMedID 885349
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AUDITORY EVOKED-POTENTIALS TO UNPREDICTABLE SHIFTS IN PITCH
PSYCHOPHYSIOLOGY
1976; 13 (1): 32-39
View details for Web of Science ID A1976BB90600006
View details for PubMedID 1244627
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EFFECTS OF STIMULUS PROBABILITY AND TASK-RELEVANCE ON EVENT-RELATED POTENTIALS
PSYCHOPHYSIOLOGY
1976; 13 (4): 311-317
View details for Web of Science ID A1976BW74100006
View details for PubMedID 951472
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CANNABIS AND ALCOHOL EFFECTS ON ASSAULTIVENESS IN ADOLESCENT DELINQUENTS
ANNALS OF THE NEW YORK ACADEMY OF SCIENCES
1976; 282 (DEC30): 85-94
View details for Web of Science ID A1976CS65400011
View details for PubMedID 1071397
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PARAMETERS OF TEMPORAL RECOVERY OF HUMAN AUDITORY EVOKED-POTENTIAL
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1976; 40 (6): 623-632
Abstract
Auditory evoked potentials (AEPs) to tone pips at three monopolar scalters were systematically varied: tone intensity (3.0, 1.5 and 0.75 sec), and direction of attention. Interstimulus intervals were computed separately for the 9 different combinations of the three possible first prior intervals (intervals between the test stimulus and the stimulus immediately preceding it) and the three possible second prior intervals (intervals between the stimulus preceding the test stimulus and the stimulus prior to that). Our results show that temporal amplitude recovery of N1 and P2 can be based solely on the first prior interval had not effect on amplitude. Furthermore, they show that it is inadvisable to use combined N1-P2 amplitude measures since the two peaks appear to be governed by separate processes. Recovery for N1 was different from that of P2, N1 showed no intensity effects while P2 did, and N1 and P2 had different topographic distributions. Directing attention to the tones did not affect N1 or P2 amplitudes but caused a highly significant increase in both N1 and P2 latency. Attention to the tones also produced a frontal negative baseline shift following them.
View details for Web of Science ID A1976BR67400006
View details for PubMedID 57048
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MOOD STATES AND 24-HOUR CARDIAC MONITORING
JOURNAL OF PSYCHOSOMATIC RESEARCH
1976; 20 (3): 179-186
View details for Web of Science ID A1976BX38200003
View details for PubMedID 972357
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ATTENTION EFFECTS ON AUDITORY EVOKED-POTENTIALS TO INFREQUENT EVENTS
BIOLOGICAL PSYCHOLOGY
1976; 4 (1): 65-77
Abstract
In two experiments, evoked potentials (EPs) were obtained for three levels of attention, defined by instructions to press a button to, listen to or ignore an infrequent event. In experiment 1, a regular train of standard tone pips was occasionally and randomly interrupted by a tone of different pitch (pitch change) or by the omission of a tone (gap). At the vertex (Cz) a late positive peak (P3) to the infrequent event became larger and later with increased attention, while the earlier negative peak (N1) became later but not larger. In experiment 2, EPs to pitch changes were recorded from Cz, frontal (Fz) and parietal (Pz) locations. All effects obtained in experiment 1 were replicated. The distribution of P3 was different during the different attention conditions.
View details for Web of Science ID A1976BU37700006
View details for PubMedID 938708
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MARIHUANA AND ETHANOL - DIFFERENTIAL EFFECTS ON TIME PERCEPTION, HEART-RATE, AND SUBJECTIVE RESPONSE
PSYCHOPHARMACOLOGY
1976; 49 (3): 275-279
Abstract
Performance on a time production task, heart rate, and subjective responses were studied in twelve male sujects given oral doses of marijuana (0.7 mg of delta-9-tetrahydrocannabinol/kg), ethanol (1.0 ml/kg), and placebo, on three testing days which were each separated by 1 week. Orders were balanced across subjects and testing conditions were double-blind. Compared to ethanol and placebo, marijuana induced a significant under-production of time intervals, suggesting an acceleration of the internal rate of time perception. The onset of this acceleration of time sense in which geophysical time seemed to pass slowly corresponded with the characteristic increase in heart rate and the onset of the subjective feelings of drug effects. Initial phases of alcohol intoxication were associated with the opposite effects on the time production task. These findings replicate previous work and indicate that an easily administered time production task provides a consistent, non-motor measure of acute marijuana intoxication and also reflects ethanol intoxication.
View details for Web of Science ID A1976CH51700010
View details for PubMedID 826945
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RELIABILITY OF CONTINGENT NEGATIVE VARIATION AND AUDITORY EVOKED-POTENTIAL
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1975; 38 (1): 45-50
Abstract
Contingent negative variations (CNVs) composed of 32 trials had a median subject consistency of 0.68 in retests separated from 5 min to 7 days. Hand measurement of the CNV was highly reliable with a median reliability of 0.96. Subject consistencies for the amplitudes and latencies of N1 and P2 components of a auditory evoked potential (AEP) had a median of 0.59 when 265 trials were averaged. These consistencies for N1 and P3 components had a median of 0.45 when only 16 trials were averaged. Median measurement reliabilities for the AEP were 0.92 for amplitudes and 0.66 for latencies.
View details for Web of Science ID A1975V066200006
View details for PubMedID 45903
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CONTINGENT NEGATIVE VARIATION DURING A MEMORY RETRIEVAL TASK
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1975; 38 (2): 171-174
Abstract
Evoked potentials were recorded from the human scalp during performance of a memory retrieval task modeled after a paradigm originated by Sternberg (1966). Subjects were required to decide whether a probe digit was contained in a series of one to four target digits presented a few seconds before. The amplitude of the contingent negative variation (CNV) preceding the probe digit and the speed of CNV resolution after the probe varied as a function of target set size. CNV amplitude was greatest when the set size was one. The smaller the set size, the more positive the evoked potential 300 msec after the probe, regardless of whether a motor response was required.
View details for Web of Science ID A1975V450300007
View details for PubMedID 45947
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MARIHUANA EFFECTS ON TAT FORM AND CONTENT
PSYCHOPHARMACOLOGIA
1975; 43 (3): 261-266
Abstract
In a double-blind study, 72 normal male subjects were given either placebo or marihuana containing 20 mg. Delta-9-tetrahydrocannabinol. Stories written to cards selected from the Thematic Apperception Test did not differ on hostile or sexual content scales between drug and placebo conditions, but 6 out of 10 scales specifically constructed to detect marihuana effects were successful at differentiating the two conditions. Under marihuana the stories had a timeless, non-narrative quality, with greater discontinuity in thought sequence and more frequent inclusion of contradictory ideas. Novelty of content was somewhat increased by marihuana, while relation to the picture, imagery, repetition, and closure were not significantly affected.
View details for Web of Science ID A1975AR45700011
View details for PubMedID 1103209
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Proceedings: Drugs, delinquency, and aggression.
Psychopharmacology bulletin
1974; 10 (4): 62-63
View details for PubMedID 4431879
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The nature of storage deficits and state-dependent retrieval under marihuana.
Psychopharmacologia
1974; 37 (4): 139-149
View details for PubMedID 4844119
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SOME MOTIVATIONAL ASPECTS OF EXERCISE
JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS
1974; 14 (1): 40-47
View details for Web of Science ID A1974T403700007
View details for PubMedID 4847321
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PREVALENCE AND METHODS OF CONTROL OF CEPHALIC SKIN POTENTIAL EEG ARTIFACT
PSYCHOPHYSIOLOGY
1974; 11 (3): 350-360
View details for Web of Science ID A1974T370500013
View details for PubMedID 4417673
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NATURE OF STORAGE DEFICITS AND STATE-DEPENDENT RETRIEVAL UNDER MARIHUANA
PSYCHOPHARMACOLOGIA
1974; 37 (2): 139-149
View details for Web of Science ID A1974T494600005
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DRUG INVOLVEMENT IN CRIMINAL ASSAULTS BY ADOLESCENTS
ARCHIVES OF GENERAL PSYCHIATRY
1974; 30 (5): 685-689
View details for Web of Science ID A1974T312000011
View details for PubMedID 4824202
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Influence of marihuana on storage and retrieval processe in memory.
Memory & cognition
1973; 1 (2): 196-200
Abstract
Following presentation and immediate free recall testing of 10 20-word lists, 48 Ss were divided into two groups, one of which received an oral dose of marihuana extract calibrated to 20 mg of Δ(1)-THC and one of which received placebo. One hour later, all Ss were administered delayed recall, recognition, and order tests on the first set of words. Presentation of another set of 10 lists followed, and there were immediate recall and delayed recall, recognition, and order tests on these words. Performance of drug and placebo Ss did not differ significantly for any of the first delayed tests. However, the performance of drug Ss was poorer than that of placebo Ss on immediate recall, delayed recall, and delayed recognition of the second set of lists. We concluded that retrieval of information relevant to the occurrence or nonocurrence of an event was not affected by marihuana intoxication. Storage difficulties probably account for memory deficits due to the drug, and these difficulties appear to occur in the process of transferring information from short-term to long-term memory.
View details for DOI 10.3758/BF03198094
View details for PubMedID 24214517
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9 -Transtetrahydrocannabinol and natural marihuana. A controlled comparison.
Archives of general psychiatry
1973; 28 (2): 278-281
View details for PubMedID 4684294
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P300 AN ORIENTING REACTION IN HUMAN AUDITORY EVOKED-RESPONSE
PERCEPTUAL AND MOTOR SKILLS
1973; 36 (1): 219-225
View details for Web of Science ID A1973O779400047
View details for PubMedID 4686714
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MARIHUANA AND SYNTHETIC DELTA-9-TRANS-TETRAHYDROCANNABINOL - SOME EFFECTS ON AUDITORY EVOKED-RESPONSE AND BACKGROUND EEG IN HUMANS
BIOLOGICAL PSYCHIATRY
1973; 6 (3): 221-233
View details for Web of Science ID A1973Q253100004
View details for PubMedID 4732253
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AUDITORY EVOKED-RESPONSES TO UNPREDICTABLE STIMULI
PSYCHOPHYSIOLOGY
1973; 10 (2): 125-138
View details for Web of Science ID A1973P225600001
View details for PubMedID 4691787
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The effect of marihuana on tracking task performance.
Psychopharmacologia
1973; 33 (3): 259-265
View details for PubMedID 4785907
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CONTINUOUS ELECTROCARDIOGRAPHIC MONITORING DURING MARIHUANA INTOXICATION
CLINICAL PHARMACOLOGY & THERAPEUTICS
1973; 14 (4): 533-540
View details for Web of Science ID A1973Q214000009
View details for PubMedID 4723261
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EVOKED-POTENTIAL CORRELATES OF SIGNAL RECOGNITION BETWEEN AND WITHIN MODALITIES
SCIENCE
1973; 181 (4098): 465-466
Abstract
Electrical responses evoked by clicks, flashes, changes in noise level, and changes in light level were recorded from the scalps of human subjects set to detect one of the stimuli. An early negative component of the evoked responses reflects selection between sensory modalities, whereas the later positive component reflects a more complex intramodal discrimination.
View details for Web of Science ID A1973Q218300031
View details for PubMedID 4718116
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INFLUENCE OF MARIHUANA ON STORAGE AND RETRIEVAL PROCESSES IN MEMORY
MEMORY & COGNITION
1973; 1 (2): 196-200
View details for Web of Science ID A1973P681300018
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DELTA9-TRANSTETRAHYDROCANNABINOL AND NATURAL MARIHUANA - CONTROLLED COMPARISON
ARCHIVES OF GENERAL PSYCHIATRY
1973; 28 (2): 278-281
View details for Web of Science ID A1973O724400016
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EFFECT OF MARIHUANA ON TRACKING TASK-PERFORMANCE
PSYCHOPHARMACOLOGIA
1973; 33 (3): 259-265
View details for Web of Science ID A1973R656600005
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Effects on humans of 9 -tetrahydrocannabinol administered by smoking.
Science
1972; 176 (4037): 934-936
Abstract
Twelve chronic marijuana users received triangle up(9)-tetrahydrocannabinol by smoking. The magnitude of their pulse increment was highly correlated with their subjective experiences. Three of the 12 subjects subsequently received triangle up(9)-tetrahydrocannabinol labeled with carbon-14; the time course of its concentration in plasma was highly correlated with the pulse increment. Subjective symptoms, however, appeared later and dissipated more slowly.
View details for PubMedID 4555981
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EFFECTS ON HUMANS OF DELTA9-TETRAHYDROCANNABINOL ADMINISTERED BY SMOKING
SCIENCE
1972; 176 (4037): 934-?
View details for Web of Science ID A1972M506300027
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EFFECT OF ATTENTION ON AVERAGE EVOKED RESPONSE TO SPEECH SOUNDS
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
1970; 29 (1): 38-?
View details for Web of Science ID A1970G756200004
View details for PubMedID 4194049
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AUDITORY EVOKED RESPONSE TO REPEATED STIMULI DURING A VIGILANCE TASK
PSYCHOPHYSIOLOGY
1969; 6 (3): 301-?
View details for Web of Science ID A1969F002500003
View details for PubMedID 5353381