All Publications

  • Time Window of Head Impact Kinematics Measurement for Calculation of Brain Strain and Strain Rate in American Football. Annals of biomedical engineering Liu, Y., Domel, A. G., Cecchi, N. J., Rice, E., Callan, A. A., Raymond, S. J., Zhou, Z., Zhan, X., Li, Y., Zeineh, M. M., Grant, G. A., Camarillo, D. B. 2021


    Wearable devices have been shown to effectively measure the head's movement during impacts in sports like American football. When a head impact occurs, the device is triggered to collect and save the kinematic measurements during a predefined time window. Then, based on the collected kinematics, finite element (FE) head models can calculate brain strain and strain rate, which are used to evaluate the risk of mild traumatic brain injury. To find a time window that can provide a sufficient duration of kinematics for FE analysis, we investigated 118 on-field video-confirmed football head impacts collected by the Stanford Instrumented Mouthguard. The simulation results based on the kinematics truncated to a shorter time window were compared with the original to determine the minimum time window needed for football. Because the individual differences in brain geometry influence these calculations, we included six representative brain geometries and found that larger brains need a longer time window of kinematics for accurate calculation. Among the different sizes of brains, a pre-trigger time of 40ms and a post-trigger time of 70ms were found to yield calculations of brain strain and strain rate that were not significantly different from calculations using the original 200ms time window recorded by the mouthguard. Therefore, approximately 110ms is recommended for complete modeling of impacts for football.

    View details for DOI 10.1007/s10439-021-02821-z

    View details for PubMedID 34231091

  • Head impact exposure and concussion in women's collegiate club lacrosse RESEARCH IN SPORTS MEDICINE Cecchi, N. J., Monroe, D. C., Fote, G. M., Small, S. L., Hicks, J. W. 2021: 1-6


    This study sought to describe head impact exposure in women's collegiate club lacrosse. Eleven women's collegiate club lacrosse players wore head impact sensors during eight intercollegiate competitions. Video recordings of competitions were used to verify impact data. Athletes completed questionnaires detailing their concussion history and perceived head impact exposure. During the monitored games, no diagnosed concussions were sustained. Three athletes reported sustaining head impacts (median = 0; range: 0-3 impacts per game). Six impacts registered by the sensors were verified on video across a total of 81 athlete-game exposures. Verified impacts had a median peak linear acceleration of 21.0 g (range: 18.3 g - 48.3 g) and peak rotational acceleration of 1.1 krad/s2 (range: 0.7 krad/s2 - 5.7 krad/s2). Women competing in collegiate club lacrosse are at a low risk of sustaining head impacts, comparable to previous reports of the high school and collegiate varsity levels of play.

    View details for DOI 10.1080/15438627.2021.1929226

    View details for Web of Science ID 000651267000001

    View details for PubMedID 33998942

  • A new open-access platform for measuring and sharing mTBI data. Scientific reports Domel, A. G., Raymond, S. J., Giordano, C., Liu, Y., Yousefsani, S. A., Fanton, M., Cecchi, N. J., Vovk, O., Pirozzi, I., Kight, A., Avery, B., Boumis, A., Fetters, T., Jandu, S., Mehring, W. M., Monga, S., Mouchawar, N., Rangel, I., Rice, E., Roy, P., Sami, S., Singh, H., Wu, L., Kuo, C., Zeineh, M., Grant, G., Camarillo, D. B. 2021; 11 (1): 7501


    Despite numerous research efforts, the precise mechanisms of concussion have yet to be fully uncovered. Clinical studies on high-risk populations, such as contact sports athletes, have become more common and give insight on the link between impact severity and brain injury risk through the use of wearable sensors and neurological testing. However, as the number of institutions operating these studies grows, there is a growing need for a platform to share these data to facilitate our understanding of concussion mechanisms and aid in the development of suitable diagnostic tools. To that end, this paper puts forth two contributions: (1) a centralized, open-access platform for storing and sharing head impact data, in collaboration with the Federal Interagency Traumatic Brain Injury Research informatics system (FITBIR), and (2) a deep learning impact detection algorithm (MiGNet) to differentiate between true head impacts and false positives for the previously biomechanically validated instrumented mouthguard sensor (MiG2.0), all of which easily interfaces with FITBIR. We report 96% accuracy using MiGNet, based on a neural network model, improving on previous work based on Support Vector Machines achieving 91% accuracy, on an out of sample dataset of high school and collegiate football head impacts. The integrated MiG2.0 and FITBIR system serve as a collaborative research tool to be disseminated across multiple institutions towards creating a standardized dataset for furthering the knowledge of concussion biomechanics.

    View details for DOI 10.1038/s41598-021-87085-2

    View details for PubMedID 33820939

  • Patterns of head impact exposure in men's and women's collegiate club water polo JOURNAL OF SCIENCE AND MEDICINE IN SPORT Cecchi, N. J., Monroe, D. C., Phreaner, J. J., Small, S. L., Hicks, J. W. 2020; 23 (10): 927–31


    Recent reports have demonstrated a risk of concussion and subconcussive head impacts in collegiate varsity and international elite water polo. We sought to characterize patterns of head impact exposure at the collegiate club level of water polo.Prospective cohort study.Head impact sensors (SIM-G, Triax Technologies) were worn by men's (n=16) and women's (n=15) collegiate club water polo players during 11 games. Peak linear acceleration (PLA) and peak rotational acceleration (PRA) of head impacts were recorded by the sensors. Two streams of competition video were used to verify and describe the nature of head impacts.Men's players sustained 52 verified head impacts of magnitude 39.7±16.3g PLA and 5.2±3.2 krad/s2 PRA, and women's players sustained 43 verified head impacts of magnitude 33.7±12.6g PLA and 4.0±2.8krad/s2 PRA. Impacts sustained by men had greater PLA than those sustained by women (p=.045). Athletes were impacted most frequently at the offensive center position, to the back of the head, and by an opponent's torso or limb.Our cohort of male and female athletes sustained relatively infrequent head impacts during water polo competitions played at the collegiate club level. The amount of head impact exposure in our cohort was dependent on player position, with offensive centers prone to sustaining the most impacts. Head impact sensors are subject to large amounts of false positives and should be used in conjunction with video recordings to verify the validity of impact data.

    View details for DOI 10.1016/j.jsams.2020.03.008

    View details for Web of Science ID 000566905200007

    View details for PubMedID 32303477

  • Effects of soccer ball inflation pressure and velocity on peak linear and rotational accelerations of ball-to-head impacts SPORTS ENGINEERING Cecchi, N. J., Monroe, D. C., Moscoso, W. X., Hicks, J. W., Reinkensmeyer, D. J. 2020; 23 (1)
  • A Dose Relationship Between Brain Functional Connectivity and Cumulative Head Impact Exposure in Collegiate Water Polo Players FRONTIERS IN NEUROLOGY Monroe, D. C., Cecchi, N. J., Gerges, P., Phreaner, J., Hicks, J. W., Small, S. L. 2020; 11: 218


    A growing body of evidence suggests that chronic, sport-related head impact exposure can impair brain functional integration and brain structure and function. Evidence of a robust inverse relationship between the frequency and magnitude of repeated head impacts and disturbed brain network function is needed to strengthen an argument for causality. In pursuing such a relationship, we used cap-worn inertial sensors to measure the frequency and magnitude of head impacts sustained by eighteen intercollegiate water polo athletes monitored over a single season of play. Participants were evaluated before and after the season using computerized cognitive tests of inhibitory control and resting electroencephalography. Greater head impact exposure was associated with increased phase synchrony [r(16) > 0.626, p < 0.03 corrected], global efficiency [r(16) > 0.601, p < 0.04 corrected], and mean clustering coefficient [r(16) > 0.625, p < 0.03 corrected] in the functional networks formed by slow-wave (delta, theta) oscillations. Head impact exposure was not associated with changes in performance on the inhibitory control tasks. However, those with the greatest impact exposure showed an association between changes in resting-state connectivity and a dissociation between performance on the tasks after the season [r(16) = 0.481, p = 0.043] that could also be attributed to increased slow-wave synchrony [F(4, 135) = 113.546, p < 0.001]. Collectively, our results suggest that athletes sustaining the greatest head impact exposure exhibited changes in whole-brain functional connectivity that were associated with altered information processing and inhibitory control.

    View details for DOI 10.3389/fneur.2020.00218

    View details for Web of Science ID 000596930200001

    View details for PubMedID 32300329

    View details for PubMedCentralID PMC7145392

  • Laboratory evaluation of a wearable head impact sensor for use in water polo and land sports PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART P-JOURNAL OF SPORTS ENGINEERING AND TECHNOLOGY Cecchi, N. J., Monroe, D. C., Oros, T. J., Small, S. L., Hicks, J. W. 2020; 234 (2): 162–69
  • Comparison of head impact attenuation capabilities between a standard American football helmet and novel protective equipment that couples a helmet and shoulder pads SPORTS ENGINEERING Cecchi, N. J., Oros, T. J., Ringhofer, J. J., Monroe, D. C. 2019; 22 (3-4)
  • Head impacts sustained by male collegiate water polo athletes PLOS ONE Cecchi, N. J., Monroe, D. C., Fote, G. M., Small, S. L., Hicks, J. W. 2019; 14 (5): e0216369


    Water polo is a contact sport that is gaining popularity in the United States and carries a risk of repeated head impacts and concussion. The frequency and magnitude of sport-related head impacts have not been described for water polo. We aimed to compare patterns of empirically measured head impact exposure of male collegiate water polo players to patterns previously reported by a survey of current and former water polo athletes. Participants wore water polo caps instrumented with head impact sensors during three seasons of collegiate water polo. Peak linear acceleration (PLA) and peak rotational acceleration (PRA) were recorded for head impacts. Athlete positions were recorded by research staff at the occurrence of each head impact. Head impacts were sustained by athletes in offensive positions more frequently than in defensive and transition positions (246, 59.9% vs. 93, 22.6% vs. 72, 17.5%). 37% of all head impacts during gameplay were sustained by athletes playing the offensive center position. Impact magnitude (means ± SD: PLA = 36.1±12.3g, PRA = 5.0±2.9 krads/sec2) did not differ between position or game scenario. Among goalies, impact frequency and magnitude were similar between games (means ± SD: 0.54±.51 hits/game, PLA = 36.9±14.2g, PRA = 4.3±4.2 krads/sec2) and practices (means ± SD: 0.96±1.11 hits/practice, PLA = 43.7±14.5g, PRA = 3.9±2.5 krads/sec2). We report that collegiate water polo athletes are at risk for sport-related head impacts and impact frequency is dependent on game scenario and player position. In contrast, magnitude does not differ between scenarios or across positions.

    View details for DOI 10.1371/journal.pone.0216369

    View details for Web of Science ID 000466511200077

    View details for PubMedID 31048869

    View details for PubMedCentralID PMC6497298

  • The Effectiveness of Protective Headgear in Attenuating Ball-to-Forehead Impacts in Water Polo. Frontiers in sports and active living Cecchi, N. J., Oros, T. J., Monroe, D. C., Fote, G. M., Moscoso, W. X., Hicks, J. W., Reinkensmeyer, D. J. 2019; 1: 2


    Recent reports have demonstrated that there is a serious risk of head impact and injury in water polo. The use of protective headgear in contact sports is a commonly accepted strategy for reducing the risk of head injury, but there are few available protective headgears for use in water polo. Many of those that are available are banned by the sport's governing bodies due to a lack of published data supporting the effectiveness of those headgears in reducing head impact kinematics. To address this gap in knowledge, we launched a water polo ball at the forehead of an anthropomorphic testing device fitted with either a standard water polo headgear or one of two protective headgears. We selected a range of launch speeds representative of those observed across various athlete ages. Mixed-model ANOVAs revealed that, relative to standard headgear, protective headgears reduced peak linear acceleration (by 10.8-21.6%; p < 0.001), and peak rotational acceleration (by 24.5-48.5%; p < 0.001) induced by the simulated ball-to-forehead impacts. We discuss the possibility of using protective headgears in water polo to attenuate head impact kinematics.

    View details for DOI 10.3389/fspor.2019.00002

    View details for PubMedID 33344926

    View details for PubMedCentralID PMC7739673