Study Finds CTE in 215 Donated Brains From Deceased Former NFL Players

A study released Tuesday found chronic traumatic encephalopathy in 215 of 235 donated brains from former NFL players who died between 2016 and 2021. Reuters and The Guardian reported that the research covered a six-year period in which 878 former NFL players died, meaning the confirmed cases represented nearly one-quarter of that full group.

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The findings do not mean that 215 of every 235 former NFL players have CTE. Only a subset of families donated brains for examination, and the condition can currently be definitively diagnosed only after death. The reported figures establish how many cases researchers identified within the studied cohort, while leaving uncertainty about the prevalence among all living and former players.

CTE is a degenerative brain disease associated with repeated blows to the head, including concussions. Reported symptoms can include problems with attention and memory, dementia, mood disorders and headaches. The study was conducted by researchers from Mass General Brigham, Boston University and the Concussion + CTE Foundation, according to the report.

Lead author Daniel Daneshvar, chair of physical medicine and rehabilitation at Mass General Brigham and an associate professor at Harvard Medical School, said repeated traumatic brain injuries are a known contributor to elevated rates of neurodegenerative disease. The researchers also found dementia was common among the brain donors and called for prevention measures centered on reducing repetitive head impacts across football.

Daneshvar stressed that players' cumulative exposure often begins well before the professional level, with impacts accumulating in youth, high school and college football. He said nearly 70% of head impacts occur in practice, arguing that limiting contact sessions could reduce exposure without changing game time. The NFL's 2011 collective bargaining agreement restricted in-season contact practices, while the Ivy League banned full-contact tackling in practices in 2016.

An NFL spokesperson said the league continues to pursue measures intended to reduce concussions and head impacts and remains committed to providing physical and mental health resources to the NFL community. The spokesperson also encouraged former players who are worried about their health to use those resources and seek treatment. Researchers likewise advised current and former athletes experiencing cognitive symptoms to obtain an evaluation from a neurodegenerative disease specialist.