Measuring electrophysiological changes induced by subconcussive impacts due to soccer ball heading

Geoffrey Brookshire ^1* Angelo Pennati ¹ Keith J. Yoder ¹ MacKenzie Tweardy ¹ Colin Quirk ¹ Marilyn Perkins ¹ Spencer Gerrol ¹ Steven Raethel ² Devin Nikjou ^3,4 Simona Nikolova ³ Michael Leonard ³ Amy Crepeau ³ David Dodick ^3,5 Todd J Schwedt ³ Ché Lucero ^1*

• ¹ SPARK Neuro, Inc., New York, United States
• ² Special Operations Command Central (SOCCENT), Tampa, United States
• ³ Mayo Clinic Arizona, Scottsdale, Arizona, United States
• ⁴ Arizona State University, Tempe, Arizona, United States
• ⁵ Atria Academy of Science and Medicine, New York, United States

A growing body of research suggests that impacts to the head, including subconcussive impacts, carry risks for long-term detrimental effects on cognition and brain health. Despite the potential for negative health consequences associated with subconcussive impacts, there is currently no reliable and objective method used in clinical practice to assess whether a particular subconcussive impact affected the brain. In this preliminary study, we developed a machinelearning classifier to detect changes in brain electrophysiological activity following subconcussive impacts that occur during soccer ball heading. We recorded EEG from soccer players before and after they repeatedly headed a soccer ball, and trained classifiers to distinguish between an individual's EEG patterns before and after these subconcussive impacts. The classifiers were able to identify post-impact EEG recordings with significantly higher accuracy than would be expected by chance, both 1 hour and 24 hours after the impacts occurred. After controlling for electrophysiological changes attributed to exercise, changes to brain activity attributable to soccer heading were detectable at 24 hours post-heading, but not at 1-hour post-heading. The observed time-course of EEG changes mirrors a similar pattern seen in traumatic brain injury, in which an inflammatory cascade is manifest 24 to 48-hours post-injury; we suggest that EEG changes following subconcussive impacts may stem from inflammation or some other physiological process that unfolds on a similar timescale. These results are an important step toward developing an EEG-based tool that can assess whether electrophysiological consequences are present following subconcussive head impacts.