BOSTON -- A researcher says Aaron Hernandez suffered severe damage to parts of the brain that play an important role in memory, impulse control and behavior.
The 27-year-old former New England Patriots player killed himself in April while serving life in prison for murder.
Dr. Ann McKee of the CTE Center at Boston University presented the findings of her examination of Hernandez's brain on Thursday.
McKee says she could not say Hernandez's behavior was a result of his severe case of chronic traumatic encephalopathy. But she says Hernandez suffered substantial damage to several important parts of the brain, including the frontal lobe.
His attorneys have sued the NFL and football helmet maker Riddell, accusing them of failing to warn Hernandez about the dangers of football.
The NFL intends to vigorously defend itself against the lawsuit filed on behalf of Aaron Hernandez's family against the league and the Patriots.
“We intend to contest the claim vigorously,” NFL spokesman Joe Lockhart said at a media briefing Friday.
Hernandez's lawyer, Jose Baez, announced the lawsuit Thursday and said tests at Boston University showed that the former Patriots tight end had a severe case of the degenerative brain disease CTE.
NBC's Mike Florio of Pro Football Talk writes the league may argue that Hernandez’s rights already have been determined by the settlement of the class action concussion suit brought by former players. The NFL doesn’t yet know whether Hernandez was part of the class, or whether he opted out of it.
Lockhart cautioned against painting Hernandez as a victim.
"His personal story is complex, it doesn’t lend itself to simple answers,” Lockhart said. “He was convicted of a homicide and his well-documented behavioral issues began long before he played in the National Football League. . . . The real victims are the friends and family of those he killed, along with his young daughter.”
Patriots coach Bill Belichick's reaction to the Hernandez lawsuit story? "I'm not a doctor," he told reporters in Foxboro on Friday.
On the question of a link between concussions and CTE, Lockhart said science hasn't been able to connect the dots yet.
“It’s a very complicated puzzle,” he said. “Every piece is important...There are a lot of dots here, and science just hasn’t been able to connect them.”
FOXBORO -- In wake of Aaron Hernandez’ estate filing a federal lawsuit against the NFL and the Patriots over the late tight end’s head trauma, Bill Belichick was expectedly mum when asked Friday about CTE.
Hernandez, who died in prison of an apparent suicide in April shortly after being acquitted of a 2012 double-murder, had “the most severe case” of chronic traumatic encephalopathy that researchers had ever seen in a 27-year-old, according to his lawyer.
Belichick, who drafted Hernandez in 2010 and coached the player until his 2013 release, reiterated his September 2016 quote about not being a doctor on Friday.
“That’s really, the whole medicals questions are ones that come outside my area,” he said Friday when asked what the team tells players about CTE. “Our medical department, our medical staff cover a lot of things on the medical end. It’s not just one specific thing. We cover a lot.”
Asked if he feels the NFL does a good enough job of warning players about CTE, Belichick repeated his answer.
“Again, I’m not a doctor. I’m not a trainer. I’m a coach,” he said. “The medical part, they handle the medical part of it. I don’t do that.”
Hernandez was listed as having one concussion during his NFL career.