Chronic traumatic encephalopathy (CTE) is a brain disorder that is likely caused by repeated head injuries. It is a progressive and fatal brain disease associated with repeated traumatic brain injuries, including concussions and repeated blows to the head. CTE causes the death of nerve cells in the brain, known as degeneration, and gets worse over time. The only way to definitively diagnose CTE is after death during an autopsy of the brain. CTE is a rare disorder that is not yet well understood and doesnt appear to be related to a single head injury. Its related to repeated head injuries, often occurring in contact sports or military combat. The development of CTE has been associated with second impact syndrome, in which a second head injury happens before previous head injury symptoms have fully resolved.

Symptoms of CTE are thought to include trouble with thinking and emotions, physical problems, and other behaviors. Early symptoms of CTE may not be noticeable at first and may include mood changes, such as depression or suicidal thoughts, personality changes, and behavior changes, such as aggression and mood swings. As the condition gets worse, more noticeable problems with thinking and memory may occur, such as short-term memory loss, confusion, difficulties with planning and organization, and problems with movement. Symptoms usually start gradually, often around 10 years after having repeated head injuries. The symptoms may get worse gradually or stay the same for years before getting worse.

CTE has been found in the brains of people who played U.S. football and other contact sports, including boxing. It also may occur in military members who were exposed to explosive blasts. Those at greatest risk for CTE are athletes who play contact sports (e.g., boxers, football players, etc.) and military veterans, likely due to their increased chances of endu...