Number and Strength of Hits Drive CTE in Football: NOT concussions

INDIANAPOLIS (WISH) — In a new study, scientists find a football players’ odds of developing chronic traumatic encephalopathy were related to how many hits to the head they received and how hard the head impacts were, not how many concussions they endured.

In the study of 631 deceased football players, the largest CTE study to date, scientists found that the number of diagnosed concussions alone was not associated with CTE risk. The research was done at Mass General Brigham, Harvard Medical School, and Boston University (BU) and was published in Nature Communications.

“These results provide added evidence that repeated non-concussive head injuries are a major driver of CTE pathology rather than symptomatic concussions, as the medical and lay literature often suggests,” said Jesse Mez, study senior author and co-director of clinical research at the BU CTE Center.

Researchers used an innovative new tool called a positional exposure matrix (PEM) that synthesized data from 34 independent studies to estimate the number and severity of football players’ head impacts over their careers.

“This study suggests that we could reduce CTE risk through changes to how football players practice and play,” said study lead author Dan Daneshvar, MD. Assistant Professor at Harvard Medical School and Physician at Mass General Brigham affiliate Spaulding Rehabilitation. “If we cut both the number of head impacts and the force of those hits in practice and games, we could lower the odds that athletes develop CTE.”

The study found that cumulative repetitive head impact exposure was associated with CTE status. Additionally, the study found that models using the intensity of impacts were better at predicting CTE status and severity than models using time on the field or the number of hits to the head alone.

“Although this study was limited to football players, it also provides insight into the impact characteristics most responsible for CTE pathology outside of football because your brain doesn’t care what hits it,” Daneshvar said. “The finding that estimated lifetime force was related to CTE in football players likely holds true for other contact sports, military exposure, or domestic violence.”