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ObjectiveAssess utility of wearable impact sensors to monitor and reduce cumulative brain injury risks in athletic and military environments.DesignAnalysis of results generated in multiple laboratory and on-field cohort studies.SettingYouth, college, and professional football, rugby, soccer, lacrosse, boxing; military training exercises.ParticipantsParticipants across multiple activities were monitored for head impacts using wearable sensors.InterventionParticipants suffering a concussion underwent neurocognitive testing and entered a supervised return-to-play protocol.Outcome measuresThe influence of sensor design and data processing on the accuracy and reproducibility of head impact data have been assessed. Differences in head impact incidence and severity have been compared between training regimes that did/did not implement behavioural modifications based on sensor data. Head impact data have been combined with finite element modelling and high resolution MRI/DSI imaging to study spatial distribution of tissue damage and changes in neural connectivity.Main resultsReduced size and weight skin-affixed sensors worn on the mastoid provide a stable and universally applicable solution for head impact monitoring. Behavioural modifications using these devices have reduced high risk head impacts by 30%−70%. Significant localised tissue damage and changes in neural connectivity are predicted and observed even in the absence of clinically diagnosed concussion symptoms.ConclusionsWearable impact sensors are enabling significant reductions in head injury risks and incidence in athletic and military environments. These devices show promise as neuro-trauma dosimeters that can assist in monitoring cumulative brain damage due to repetitive sub-concussive head impacts, and developing more comprehensive and personalised remove-from-play thresholds.Competing interestsX2 Biosystems designs and manufactures wearable impact sensors

ObjectiveTest for a dose dependent relationship between cumulative sub-concussive head trauma loading and localised changes of brain white matter in college athletes.DesignProspective cohort studySettingNCAA Division I Women’s SoccerParticipants10 players were monitored for head impacts throughout a soccer season using wearable sensors. Linear and rotational accelerations recorded during impacts were processed to calculate the cumulative impact power. Diffusion spectrum imaging (DSI) data were acquired at season start and at 3 additional intervals. 11 age and gender matched control data sets were acquired.InterventionOne athlete suffered a concussion, was removed from play for neurocognitive testing, and entered a supervised return-to-play protocol.Outcome measuresCumulative impact power was used as a measure of the head trauma load accumulated prior to each MRI. Multi-dimensional anisotropy (MDA) values assessed localised severity of white matter changes. Session specific differences between each player’s MDA values and those of the control population were used to relate cumulative impact power and the severity of white matter changes.Main resultsHighly significant clusters of abnormal voxels were observed in athletes with no diagnosed concussion symptoms. Injury severity correlated with cumulative head impact power and demonstrated a pronounced threshold behaviour. MDA diffusion changes were located mainly within the frontal and occipital cortex at the gray-white boundary, and to a lesser degree in deep subcortical areas where there is a higher proportion of crossing fibres.ConclusionsThis cohort demonstrates dose dependent changes in white matter integrity as a function of cumulative sub-concussive head trauma.Competing interestsSG is supported, in part, by a research grant from X2 Biosystems and a General Electric-National Football League Head Health Challenge award.