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CARE Consortium: Accounting for variance in concussion tolerance between individuals

While concussion researchers have been using helmet accelerometers to measure head impacts for more than a decade, the connection between the biomechanical forces of the head impacts the players receive and the clinical effect of those impacts is poorly defined. To seek clarity, Steven Rowson, an associate professor in Virginia Tech’s department of biomedical engineering and mechanics, led a team of researchers that delved into accelerometer data collected from 502 college football players taking part in the NCAA-Department of Defense Concussion Assessment, Research and Education Consortium study. The researchers compared data from concussed athletes with matched controls to gain a better understanding of individual tolerance for concussion. Their findings were published this summer in the Annals of Biomedical Engineering.

What did the study find?

Of the 502 players who contributed data, 44 sustained a total of 49 concussions. Those who were injured were compared to matched controls of comparable height, weight and body mass (which researchers posited might correlate with comparable tolerance to head impacts). Those who suffered concussions were found to have experienced more head impacts than their matched controls in the time leading up to the injury, and measures of magnitude were found to be greater in concussed subjects relative to their controls.

What are the implications?

The findings build on previous research that suggests cumulative exposure to head impact, not merely the force of a single impact, is a strong predictor of concussion and that individuals have different thresholds for the amount of head impact they can sustain before suffering a clinical concussion. When compared with control subjects of a similar size and position, the researchers concluded, “Our analysis here indicates a need for individual-specific risk analyses that consider a person’s impact history and factors that might influence tolerance to head acceleration.”

What’s next?

The paper represents one small step of many needed to gain a better grasp on individual concussion tolerance. The researchers identified that the study has several limitations, and their analysis was based on many assumptions, including, among others, those related to how player size correlates to concussion tolerance and the known underreporting of concussion among football players as limiting factors in their analysis. Additionally, the researchers did not consider impact location and head rotation in the analysis, and they suggest that future analyses should consider the role of these among other stated limitations.