SAN FRANCISCO (CBS SF) – The researcher who conducted the study on the brain of late Raiders great Kenny Stabler said she was surprised by the number of CTE lesions in his brain.

Dr. Ann McKee, a professor of neurology at Boston University, told KCBS that the disease was very prevalent in Stabler’s amygdala and hippocampus – areas of the brain “extremely important for learning and memory and emotional regulation.”

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“His brain was really riddled with the lesions of CTE,” she told KCBS. “What was particularly surprising was that it involved the deep structures – the hippocampus and amygdala…Given the fact that he was only 69 – it was a striking amount of CTE.”

McKee said Stabler was the sixth quarterback who has allowed her group to study their brain after their death. All six have had evidence of CTE in their brains.

“We know there are certain positions that get repetitive head trauma and injuries,” she said. “But it’s surprising to see it a quarterback.”

She said the extent of the disease seems to depend on length of time a player played and his age at the time of death. Stabler played organized football for 28 years.

“The older a player is when he dies, generally the worst the disease is,” she told KCBS.

Stabler also was known for a lifestyle of drinking and smoking.  But McKee said so far there is no indication that drinking and smoking has an impact on CTE.

“You don’t get CTE from drinking or smoking,” she said. “We don’t see it in alcoholics or heavy smokers…But you have the disease does it make it worse? That’s for future study.”

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And it seems there will be plenty of material for future study.

“We have a busy pipeline,” she said of brains being donated for study. “We are getting one or two players (brains) a week. Not all are professional athletes. There are former high school and college athletes. And they all are not from football. Hockey, soccer, military veterans – anyone who has had repetitive brain trauma.”

Stabler, who died of colon cancer at 69 in July, had Stage 3 chronic traumatic encephalopathy, McKee said.

The disease, which can only be diagnosed after death, is linked to repeated brain trauma and associated with symptoms such as memory loss, depression and progressive dementia. CTE has been found in the brains of dozens of former football players.

According to Chris Nowinski, the founder of the Concussion Legacy Foundation, Stabler told his family he wanted to have his brain studied after learning that former NFL linebacker Junior Seau had been diagnosed with the disease. In 2012, Seau shot himself in the chest at the age of 43.

“What is interesting about Ken Stabler is that he anticipated his diagnosis years in advance,” Nowinski told the AP. “And even though he’s a football icon he began actively distancing himself from game in his final years, expressing hope that his grandsons would choose not to play.”

The left-handed Stabler, nicknamed “Snake” for his ability to escape from defenders, led Alabama to an undefeated season in 1966. A second-round draft pick by Oakland, he was the NFL’s Most Valuable Player in 1974, and led the Raiders to victory in the 1977 Super Bowl.

In all, Stabler threw for 27,938 career yards and had a .661 winning percentage over 15 seasons, which also included stints with the Houston Oilers and New Orleans Saints. He was selected as a finalist for the Hall of Fame by its Seniors Committee; the inductees will be announced on Saturday.

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