BMX legend Dave Mirra, who committed suicide in February, had a brain disease prior to his death often found in athletes who suffered concussions, multiple neuropathologists confirmed on Tuesday, May 24.

A University of Toronto neuropathologist told ESPN that the late athlete was diagnosed with chronic traumatic encephalopathy, commonly known as CTE. According to the site, Mirra is the first action sports athlete to be diagnosed with the neurodegenerative disease, which can lead to dementia, memory loss and depression.

The professional biker, who also hosted two seasons of MTV’s Real World/Road Rules Challenge and once held the record for the most X Games medals, was found dead inside his truck in Greenville, North Carolina, with self-inflicted gunshot wounds to the head on February 4. He was 41.

The tau protein deposits found in Mirra’s brain were “indistinguishable” from those found in the brains of former football and hockey players with CTE, according to ESPN. “It’s assumed it is related to multiple concussions that happened years before,” Dr. Lili-Naz Hazrati explained.

Mirra fractured his skull when he was hit by a car at age 19, in addition to incurring “countless” concussions during his BMX career. He retired in 2011 but later dabbled in boxing during his free time.

The rider’s widow, Lauren Mirra, also revealed that she noticed changes in his mood during the final year of his life.

“He wasn’t able to be present in any situation or conversation, so it was hard to be in a relationship with him to any degree,” she told ESPN. “He was lost. I looked straight through him on a few occasions. And I was like, ‘Where are you? Where are you? What is wrong?’”