Aaron Hernandez's CTE Was Most Severe Ever Found at 27

Former New England Patriots player Aaron Hernandez suffered severe damage to parts of the brain that play an important role in memory, impulse control, and behavior, a researcher who studied his brain said Thursday. Dr. Ann McKee, director of the CTE Center at Boston University, said she could not "connect the dots" between Hernandez's severe case of chronic traumatic encephalopathy, which is linked to repeated blows to the head, and his behavior. The 27-year-old hanged himself in April while serving life in prison for murder. But McKee said Hernandez experienced substantial damage to key parts of the brain, including the hippocampus—which is important to memory—and the frontal lobe, which is involved in problem solving, judgment, and behavior, the AP reports.

"In any individual we can't take the pathology and explain the behavior," said McKee, who has studied hundreds of brains from football players, college athletes, and even younger players, donated after their deaths. "But we can say collectively, in our collective experience, individuals with CTE—and CTE of this severity—have difficulty with impulse control, decision-making, inhibition of impulses or aggression, often emotional volatility and rage behaviors," she said. Hernandez inherited a genetic profile that may have made him more susceptible to developing the disease, McKee said. She said Hernandez had the most severe case of CTE they've seen in someone his age. Hernandez was diagnosed with Stage 3, out of 4, of the disease. "Individuals with similar gross findings at autopsy were at least 46 years old at the time of death," McKee said. Per the Washington Post, she called Hernandez's brain "one of the most significant contributions to our work." (More Aaron Hernandez stories.)