Boston University doctors revealed Demaryius Thomas had Stage 2 CTE at the time of his death.
The former NFL wideout unexpectedly died in December just two weeks shy of his 34th birthday. Thomas' family believed seizures, which Thomas suffered from due to a 2019 car accident, were the cause of death. The coroner's office in Georgia, where Thomas resided, has yet to rule an official cause of death.
Thomas' parents donated his brain to science and researchers at BU uncovered the diagnosis, according to parents of the former Denver Broncos star, who revealed as much to ABC News.
"We found what we've seen in so many other players under the age of 34," Dr. Ann McKee, the director of Neuropathology Core at Boston University, told ABC News. "On the basis of multiple lesions in the frontal lobes and temporal lobe are beginning degeneration of deeper areas of the brain. He was diagnosed with CTE. Stage two.
"CTE itself does not cause death. You don't die from CTE. What CTE does is it changes your behavior and your personality."
Thomas' father, Bobby Thomas, revealed his son complained of headaches daily and said he was "paranoid, like all the time."
