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CARE Consortium: Association of head impact mechanics and concussion symptoms

Harder hits do not correlate with harsher symptoms

Do more severe head impacts translate to greater injury risks and worse concussion symptoms? Steven Rowson, an assistant professor for the Virginia Tech-Wake Forest Center for Injury Biomechanics, led a team of investigators that examined that question. Their work, which relied on data from helmet accelerometers in 22 college football players who sustained concussions while taking part in the Concussion Assessment, Research and Education Consortium study, resulted in a November 2017 paper that was published in the Journal of Neurotrauma.

What did the study find?

The accelerometers measured both linear and rotational acceleration. The intensity of those forces at impact did not correlate to symptom severity. Nor was there a correlation between impact location and the presence of any individual symptoms. While, as a group, head acceleration levels at impact for hits that caused a concussion did not stand out from those that did not cause a concussion, concussive impacts were always among the most severe hits suffered by an individual player.

What are the implications?

The finding that there is no clear universal impact threshold across athletes is significant. It implies that some athletes may be able to tolerate head impact exposure without sustaining an injury that others, for reasons that are not clear, cannot.

“This suggests tolerance to head acceleration might be individual-specific,” the paper said. “Meaning similar biomechanical inputs can produce different injury presentations between individuals.”

What’s next?

The notion that individual tolerance to concussive forces can vary among athletes will help future researchers shape studies designed to root out what factors contribute to those differences. The goal? In the future, concussion tolerance would be determined on an individual basis, and clinical decisions can be made accordingly. Reaching that point, though, will require a great deal more research.

“Future investigations should consider individual-specific analyses of tolerance to head acceleration and injury response,” the paper said. “Our reasoning will lead to advances in our study design and analytical approaches within the larger CARE Consortium dataset to address this and other important clinical research questions.”