According to Dr. Hazrati, Mirra's brain's tau proteins, showed the same kind of damage as the brains of other affected athletes. These proteins are a major element in the neurons of the central nervous system that form abnormal deposits in the brains of CTE patients. At present, CTE can only be diagnosed after death.
"I couldn't tell the difference [between Mirra's samples and confirmed CTE cases]," Dr. Hazrati told ESPN The Magazine. "The trauma itself defines the disease, not how you got the trauma. It's assumed it is related to multiple concussions that happened years before."
According to the Mayo Clinic, CTE can manifest as emotional issues in living patients, something Mirra's widow told ESPN The Magazine the late star suffered from.
"I started to notice changes in his mood. And then it quickly started to get worse," Lauren Mirra said. "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. 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?'"
While we don't normally think of motorsports as a traditional contact sport, CTE has taken on a more prominent roll following Mirra's suicide. Safety pioneer Bill Simpson put his expertise to use helping combat CTE and concussions in football, while NASCAR driver Dale Earnhardt, Jr. made headlines earlier this year when he announced he'd donate his brain to CTE research following his death.