Aaron Hernandez was diagnosed with the most severe case of chronic traumatic encephalopathy ever discovered in a person his age. The damage was so significant that it would have certainly affected his decision-making, judgment and cognition.

Ann McKee, the head of BU’s CTE Center, which has studied the disease caused by repetitive brain trauma for more than a decade, called Hernandez’s brain “one of the most significant contributions to our work” because of the brain’s pristine condition and the rare opportunity to study the disease in a 27-year-old.

Hernandez committed suicide in April while serving a life sentence for murder.

Doctors found Hernandez had Stage 3 CTE, which researchers had never seen in a brain younger than 46 years old.

“In this age group, he’s clearly at the severe end of the spectrum,” McKee said. “There is a concern that we’re seeing accelerated disease in young athletes. Whether or not that’s because they’re playing more aggressively or if they’re starting at younger ages, we don’t know. But we are seeing ravages of this disease, in this specific example, of a young person.”

Hernandez’s estate filed a federal lawsuit against the Patriots in September, alleging the Patriots knew hits to the head could lead to brain damage and failed to protect him.