This isn’t the first study of its kind. Last year Frontline reported that researchers with the Department of Veterans Affairs and Boston University found chronic traumatic encephalopathy (CTE), which the Mayo Clinic defines as “brain degeneration likely caused by repeated head traumas” that is “a diagnosis only made at autopsy,” in 96 percent of the NFL players they examined and in 79 percent of football players at various levels of play.

The researchers studied 165 deceased people who had played the sport in high school, college or professionally, and found evidence of CTE in 131 of them.

But this newest study is “one of the largest studies to date in living retired NFL players” and the “first to demonstrate significant objective evidence for traumatic brain injury in these former players,” study author Dr. Francis X. Conidi of the Florida Center for Headache and Sports Neurology and Florida State University College of Medicine said in the release.