CTE

CTE, or chronic traumatic encephalopathy, is a progressive brain condition caused by repeated head injuries, commonly found in contact sports athletes and military personnel. It leads to dementia-like symptoms and can only be definitively diagnosed post-mortem through autopsy. The condition was first identified in boxers in the 1920s and later linked to NFL players like Mike Webster.

Marshawn Kneeland, a Dallas Cowboys defensive end, had early stage CTE linked to repeated head trauma at the time of his death by suicide in November 2025 after a high-speed chase with police. His family released postmortem analysis findings through the Concussion & CTE Foundation.

Dallas Cowboys defensive end Marshawn Kneeland was diagnosed with early stage CTE at the time of his death. CTE is a degenerative brain disease found in athletes in contact sports, combat veterans, and others who experience repetitive blows to the head.

Marshawn Kneeland, a Dallas Cowboys defensive end, was posthumously diagnosed with Stage 1 CTE after his death by suicide in November 2025. His family donated his brain for research, and Boston University’s CTE Center confirmed the diagnosis, highlighting the disease’s prevalence in young athletes.

CTE, a brain disease that can't be confirmed until after death, is suspected by former soldier Brendan Hynes. Canadian scientists are researching potential solutions to diagnose CTE while patients are alive.

Claude Lemieux’s brain is being donated to Boston University’s CTE Center to study repetitive brain injuries. Lemieux, a former NHL player who played nearly 1,500 games and won four Stanley Cups, died by suicide at 60. His family requested findings be shared publicly with his name but cautioned against drawing diagnostic conclusions.