Clinical Focus

  • Sleep Medicine

Academic Appointments

Professional Education

  • Board Certification, American Board of Psychiatry and Neurology, Sleep Medicine (2017)
  • Board Certification, American Board of Psychiatry and Neurology, Neurology (2015)
  • Fellowship, Stanford University, Sleep Medicine (2016)
  • Residency, UT Southwestern Medical Center, Neurology (2015)
  • M.D., UT Southwestern Medical Center, Medicine (2011)

All Publications

  • What Is Narcolepsy? JAMA Sum-Ping, O., Mignot, E. 2023

    View details for DOI 10.1001/jama.2023.5149

    View details for PubMedID 37145499

  • Sodium Oxybate in Treatment-Resistant REM Sleep Behavior Disorder. Sleep During, E. H., Hernandez, B., Miglis, M. G., Sum-Ping, O., Hekmat, A., Cahuas, A., Ekelmans, A., Yoshino, F., Mignot, E., Kushida, C. A. 2023


    Symptomatic therapies for REM sleep behavior disorder (RBD) are limited. Sodium oxybate (SXB), a gamma-aminobutyric acid (GABA)-B agonist, could be effective but has not been evaluated against placebo.This double-blind, parallel-group, randomized, placebo-controlled trial in 24 participants was conducted at the Stanford Sleep Center. Patients were adults with definite iRBD or Parkinson's disease and probable RBD (PD-RBD), and persistence of ≥ 2 weekly episodes despite standard therapy. Patients were randomized 1:1 to receive SXB during a 4-week titration followed by a 4-week stable dosing period. Primary outcome was number of monthly RBD episodes according to a diary filled by patients and partners. Secondary outcomes were severity, number of severe RBD episodes, and objective RBD activity on video-polysomnography.12 iRBD and 12 PD-RBD participated (mean 65.8 years), and 22 (n = 10 SXB, 12 placebo) completed the study. Although no significant between-group difference was found, SXB showed reduction of monthly RBD episodes by 23.1 (95% CI -36.0, -10.2; P=0.001) versus 10.5 with placebo (95% CI, -22.6, 1.6; P=0.087). Improvement from baseline was similarly observed for RBD overall severity burden (each episode weighted for severity), number of severe episodes, and objective RBD activity per video-polysomnography. Two participants receiving SXB withdrew due to anxiety and dizziness. The majority of adverse events otherwise resolved with dose adjustment.SXB could reduce RBD symptoms; however, response was inconsistent and a large placebo effect was observed across patient-reported outcomes. Larger studies using objective endpoints are needed.

    View details for DOI 10.1093/sleep/zsad103

    View details for PubMedID 37052688

  • Myalgic Encephalomyelitis/Chronic Fatigue Syndrome is common in post-acute sequelae of SARS-CoV-2 infection (PASC): Results from a post-COVID-19 multidisciplinary clinic. Frontiers in neurology Bonilla, H., Quach, T. C., Tiwari, A., Bonilla, A. E., Miglis, M., Yang, P. C., Eggert, L. E., Sharifi, H., Horomanski, A., Subramanian, A., Smirnoff, L., Simpson, N., Halawi, H., Sum-Ping, O., Kalinowski, A., Patel, Z. M., Shafer, R. W., Geng, L. C. 2023; 14: 1090747


    The global prevalence of PASC is estimated to be present in 0·43 and based on the WHO estimation of 470 million worldwide COVID-19 infections, corresponds to around 200 million people experiencing long COVID symptoms. Despite this, its clinical features are not well-defined.We collected retrospective data from 140 patients with PASC in a post-COVID-19 clinic on demographics, risk factors, illness severity (graded as one-mild to five-severe), functional status, and 29 symptoms and principal component symptoms cluster analysis. The Institute of Medicine (IOM) 2015 criteria were used to determine the Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) phenotype.The median age was 47 years, 59.0% were female; 49.3% White, 17.2% Hispanic, 14.9% Asian, and 6.7% Black. Only 12.7% required hospitalization. Seventy-two (53.5%) patients had no known comorbid conditions. Forty-five (33.9%) were significantly debilitated. The median duration of symptoms was 285.5 days, and the number of symptoms was 12. The most common symptoms were fatigue (86.5%), post-exertional malaise (82.8%), brain fog (81.2%), unrefreshing sleep (76.7%), and lethargy (74.6%). Forty-three percent fit the criteria for ME/CFS, majority were female, and obesity (BMI > 30 Kg/m2) (P = 0.00377895) and worse functional status (P = 0.0110474) were significantly associated with ME/CFS.Most PASC patients evaluated at our clinic had no comorbid condition and were not hospitalized for acute COVID-19. One-third of patients experienced a severe decline in their functional status. About 43% had the ME/CFS subtype.

    View details for DOI 10.3389/fneur.2023.1090747

    View details for PubMedID 36908615

    View details for PubMedCentralID PMC9998690

  • Ambulatory Detection of Isolated Rapid-Eye-Movement Sleep Behavior Disorder Combining Actigraphy and Questionnaire. Movement disorders : official journal of the Movement Disorder Society Brink-Kjaer, A., Gupta, N., Marin, E., Zitser, J., Sum-Ping, O., Hekmat, A., Bueno, F., Cahuas, A., Langston, J., Jennum, P., Sorensen, H. B., Mignot, E., During, E. 2022


    BACKGROUND: Isolated rapid-eye-movement sleep behavior disorder (iRBD) is in most cases a prodrome of neurodegenerative synucleinopathies, affecting 1% to 2% of middle-aged and older adults; however, accurate ambulatory diagnostic methods are not available. Questionnaires lack specificity in nonclinical populations. Wrist actigraphy can detect characteristic features in individuals with RBD; however, high-frequency actigraphy has been rarely used.OBJECTIVE: The aim was to develop a machine learning classifier using high-frequency (1-second resolution) actigraphy and a short patient survey for detecting iRBD with high accuracy and precision.METHODS: The method involved analysis of home actigraphy data (for seven nights and more) and a nine-item questionnaire (RBD Innsbruck inventory and three synucleinopathy prodromes of subjective hyposmia, constipation, and orthostatic dizziness) in a data set comprising 42 patients with iRBD, 21 sleep clinic patients with other sleep disorders, and 21 community controls.RESULTS: The actigraphy classifier achieved 95.2% (95% confidence interval [CI]: 88.3-98.7) sensitivity and 90.9% (95% CI: 82.1-95.8) precision. The questionnaire classifier achieved 90.6% accuracy and 92.7% precision, exceeding the performance of the Innsbruck RBD Inventory and prodromal questionnaire alone. Concordant predictions between actigraphy and questionnaire reached a specificity and precision of 100% (95% CI: 95.7-100.0) with 88.1% sensitivity (95% CI: 79.2-94.1) and outperformed any combination of actigraphy and a single question on RBD or prodromal symptoms.CONCLUSIONS: Actigraphy detected iRBD with high accuracy in a mixed clinical and community cohort. This cost-effective fully remote procedure can be used to diagnose iRBD in specialty outpatient settings and has potential for large-scale screening of iRBD in the general population. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

    View details for DOI 10.1002/mds.29249

    View details for PubMedID 36258659

  • Circadian rhythms of risk factors and management in atherosclerotic and hypertensive vascular disease: Modern chronobiological perspectives of an ancient disease. Chronobiology international Geng, Y. J., Smolensky, M. H., Sum-Ping, O., Hermida, R., Castriotta, R. J. 2022: 1-30


    Atherosclerosis, a chronic inflammatory disease of the arteries that appears to have been as prevalent in ancient as in modern civilizations, is predisposing to life-threatening and life-ending cardiac and vascular complications, such as myocardial and cerebral infarctions. The pathogenesis of atherosclerosis involves intima plaque buildup caused by vascular endothelial dysfunction, cholesterol deposition, smooth muscle proliferation, inflammatory cell infiltration and connective tissue accumulation. Hypertension is an independent and controllable risk factor for atherosclerotic cardiovascular disease (CVD). Conversely, atherosclerosis hardens the arterial wall and raises arterial blood pressure. Many CVD patients experience both atherosclerosis and hypertension and are prescribed medications to concurrently mitigate the two disease conditions. A substantial number of publications document that many pathophysiological changes caused by atherosclerosis and hypertension occur in a manner dependent upon circadian clocks or clock gene products. This article reviews progress in the research of circadian regulation of vascular cell function, inflammation, hemostasis and atherothrombosis. In particular, it delineates the relationship of circadian organization with signal transduction and activation of the renin-angiotensin-aldosterone system as well as disturbance of the sleep/wake circadian rhythm, as exemplified by shift work, metabolic syndromes and obstructive sleep apnea (OSA), as promoters and mechanisms of atherogenesis and risk for non-fatal and fatal CVD outcomes. This article additionally updates advances in the clinical management of key biological processes of atherosclerosis to optimally achieve suppression of atherogenesis through chronotherapeutic control of atherogenic/hypertensive pathological sequelae.

    View details for DOI 10.1080/07420528.2022.2080557

    View details for PubMedID 35758140

  • Impact of Sleep on Cardiovascular Health: A Narrative Review Heart and Mind Sum-Ping, O., Geng, Y. 2022; 6 (3): 120-126

    View details for DOI 10.4103/hm.hm_29_22

  • Phases of the Diagnostic Journey: A Framework International Archives of Internal Medicine Geng, L., Sum-Ping, O., Geng, Y. 2019
  • Pathogenesis of Hypersomnia Reference Module in Neuroscience and Biobehavioral Psychology Sum-Ping, O., Darby, C., Guilleminault, C. 2017
  • Kleine-Levin Syndrome CURRENT TREATMENT OPTIONS IN NEUROLOGY Sum-Ping, O., Guilleminault, C. 2016; 18 (6)


    Kleine-Levin Syndrome [KLS] is often under-recognized and also misdiagnosed. When suspicion for KLS is raised, a thorough clinical evaluation should be performed, including detailed history from family members and a neurologic and psychiatric examination. Additional studies may include PSG, EEG, neuroimaging, as well as serological and CSF studies to rule out alternative diagnoses as clinically indicated. After arriving at a diagnosis of KLS, the foundation of care is supportive. Patients and their families should be provided with education about the disease. During symptomatic periods, patients should be allowed to rest at home under caregiver supervision. Caregivers should pay special attention to the patient's eating habits and mood. Patients should not be allowed to drive or operate heavy machinery during these episodes. In between episodes, avoidance of reported triggers, such as alcohol and infection are encouraged as is maintenance of a regular sleep-wake cycle. Pharmacologic therapy has not been well-studied and for most patients is not necessary. For more severe cases, targeted symptomatic therapy, such as modafinil or amantadine for somnolence or risperidone for psychosis may be considered depending on the patient's symptomatology. Lithium has the best data to support its use as a prophylactic agent and for patients with severe or frequent episodes, may be considered.

    View details for DOI 10.1007/s11940-016-0409-2

    View details for PubMedID 27073070