The most disturbing legacy of football’s concussion crisis emerged after players died. Chronic traumatic encephalopathy, or CTE, is a degenerative brain disease associated with repetitive head trauma; researchers believe abnormal tau proteins gradually spread through the brain, damaging and killing brain cells. Former football players have reported memory loss, depression, anxiety, headaches, sleep problems, behavioral changes, and other debilitating symptoms after retirement, while some player suicides and premature deaths intensified public concern about the long-term cost of the sport.
The post-mortem evidence became increasingly stark. On September 30, 2014, Boston University researchers reported CTE in 76 of 79 examined brains from former NFL players. By January 2017, the figure had reached 90 of 94, and a 2017 study in the Journal of the American Medical Association found CTE pathology in 110 of 111 donated former NFL brains. A later study of 338 donated NFL brains reported pathology in 315, or 93.2 percent. These figures do not establish that nearly all NFL players develop CTE, because brain donations are heavily affected by selection bias: families are more likely to donate the brains of players who showed troubling symptoms. Nevertheless, research has found that the odds of CTE approximately doubled for every 2.6 additional years of football participation, turning repetitive head impacts from an accepted occupational hazard into one of the sport’s central medical tragedies.
Follow the sources
Status and citations are supplied by the archive. AI concept art is an interpretation, not historical evidence.