Boston scientists have diagnosed former Eagles and Patriots fullback Kevin Turner with one of the most severe cases of chronic traumatic encephalopathy ever seen, pinpointing it as a likely cause for the former fullback’s ALS.

The diagnosis, which can only be definitively determined via autopsy, is a neurodegenerative disease caused by repeated head trauma.

Announcing the results of their study at a conference at Boston University on Thursday, the doctors say Turner developed chronic traumatic encephalopathy over 25 years, playing from youth football up through the NFL. The severity of CTE found in Turner's brain “was extraordinary and unprecedented,” the Boston Herald reported

Turner got his start at University of Alabama in 1988 before being drafted by the New England Patriots in the early 1990s, where he played three seasons. He finished his career with five seasons with the Philadelphia Eagles. He died in March after a six-year battle with amyotrophic lateral sclerosis, also known as Lou Gherig’s disease or ALS, CNN reported. He was 46.

Turner believed his ALS was triggered from the repeated concussions he endured as a direct result of the eight seasons he played in the NFL.

Turner was the leading plaintiff in the concussion lawsuit brought against the league by former NFL players.

Researchers at Boston University have teamed with National Institutes of Health, the Department of Veterans Affairs, the Concussion Legacy Foundation, studying more than 280 donated brains of former professional and college football players.

Scientists believe CTE is caused by repeated hits to the head, which then result in a buildup of the abnormal protein tau.