Kevin Turner, the former fullback for the Philadelphia Eagles and New England Patriots who helped lead concussion litigation against the NFL, suffered from advanced chronic traumatic encephalopathy, Boston University researchers announced Thursday.
Turner died in March at age 46 after a six-year struggle with amyotrophic lateral sclerosis, better known as Lou Gehrig's disease.
The researchers who examined Turner's brain tissue found evidence of CTE, the neurodegenerative disease that can only be definitively confirmed after death and is connected to repeated brain trauma.
"The severity of Mr. Turner's CTE was extraordinary and unprecedented for an athlete who died in his 40s," Dr. Ann McKee, director of Boston University's CTE Center, said in a statement.
Another doctor involved in the case, Robert Cantu, linked the extent of Turner's CTE to the length of his playing career.
"We believe the extreme severity … is related to his 25-season career and the fact he began playing tackle football at age 5, while his brain was still rapidly developing and more vulnerable," Cantu said.
Dozens of other former NFL players have been posthumously diagnosed with CTE. They include Frank Gifford, Junior Seau and Mike Webster, all members of the Pro Football Hall of Fame.
An NFL-commissioned actuarial report in 2014 predicted that three in 10 retired players will develop a serious condition like Alzheimer's disease or ALS. It didn't project future cases of CTE.
Turner was a lead plaintiff in long-running concussion litigation by retired players against the NFL. A federal judge granted final approval in 2015 to a deal to resolve the matter between the league and more than 20,000 retired players, but it is on hold pending an appeal to the U.S. Supreme Court.