Aim & Research Question This study used accurate head impact monitoring mouthguard data, video review of visible concussion signs (VS), and a validated brain injury model to predict areas of the brain most affected by a head impact. The research question was whether brain simulation magnitude and location of highest strain would correlate to clinical concussion signs observed on video.

Design Retrospective Observational.

Cohort/Setting Military service members in training and athletics, as well as civilian athletes.

Participants N=973.

Independent Variables Video review of VS by an expert rater.

Outcome Measures VS of concussion based on Davis et al. (2019), accurate impact monitoring mouthguard data, brain strain magnitude from a validated computational model.

Main Results 54,602 impacts across 3449 subject-days of participation were collected. VS were seen in n=57 impacts (0.1%). All VS impacts were in the top 1% by magnitude. The maximum strain location in the brain correlated to VS in 71% of cases. No VS impacts, including impacts with loss of consciousness, had strain levels larger than critical levels from Takhounts et al. (2008).

Conclusions Impacts with VS of concussion had significantly greater measured force than those without. The computational model results had good correlation with the likely VS region of the brain that was affected in the impact. The previous brain model strain limits may need to be re-examined to correlate more closely with VS seen in the real-world.