Mirra's family urged doctors to test his brain for chronic traumatic encephalopathy (CTE) after his death, and they have concluded the neurodegenerative disease, most commonly found in professional athletes who have suffered multiple concussions, was present.

Mirra is the first action sports athlete to be diagnosed with the disease, which can lead to dementia, memory loss and depression, according to ESPN.

University of Toronto neuropathologist Dr. Lili-Naz Hazrati concluded that Mirra suffered from CTE before his death and multiple neuropathologists have confirmed the diagnosis.

"It's assumed it is related to multiple concussions that happened years before," Hazrati told ESPN The Magazine.