Late Raiders quarterback Ken Stabler — the 1974 NFL MVP, a Super Bowl winner and this year a finalist for the Pro Football Hall of Fame — has been diagnosed with chronic traumatic encephalopathy, or CTE, the degenerative brain disease believed to be caused by repeated blows to the head, researchers at Boston University said.
Stabler, who died last year of colon cancer at 69, is one of the highest-profile players to have had CTE. The list, now well over 100, includes at least seven members of the Hall of Fame, including Junior Seau, Mike Webster and Frank Gifford.
The day after Stabler died July 8, his brain was removed during an autopsy and ferried to scientists in Massachusetts. Over several months, it was dissected for clues, as Stabler had wished, to help those left behind understand why his mind seemed to slip so precipitously in his final years.
On a scale of 1 to 4, Stabler had high Stage 3 CTE, researchers at Boston University said. One of them, Dr. Ann McKee, said the disease, which can be diagnosed only after death, was widespread throughout his brain, with "quite severe" damage to the regions involving learning, memory and regulation of emotion.
"We've now found CTE in former NFL players who played every position except kicker," said McKee, a professor of neurology at Boston University. "While we know on average that certain positions experience more repetitive head impacts and are more likely at greater risk for CTE, no position is immune."
The relationship between concussions and brain degeneration is still poorly understood, and some experts caution that other factors, such as unrelated mood problems or dementia, might contribute to symptoms experienced by those later found to have had CTE.
McKee said there was no evidence of any other brain disorder "to explain the difficulties he experienced during life." The extent of the damage to Stabler's brain was surprising because he was relatively young when he died and because he was a quarterback and thought to be less exposed to repeated head trauma, she said.
Scientists are quick to note that they do not understand why some players get CTE and others do not.