Chronic traumatic encephalopathy (CTE) is a brain disorder likely caused by repeated head injuries. It causes the death of nerve cells in the brain, known as degeneration. CTE gets worse over time. The only way to definitively diagnosis CTE is after death during an autopsy of the brain.
CTE is a rare disorder that is not yet well understood. CTE doesn't appear to be related to a single head injury. It's 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.
Experts are still trying to understand how repeated head injuries and other factors might contribute to the changes in the brain that result in CTE. Researchers are looking into how the number of head injuries someone experiences and how bad the injuries are may affect risk of CTE.
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. Symptoms of CTE are thought to include trouble with thinking and emotions, physical problems, and other behaviors. It's thought that these develop years to decades after head trauma occurs.
CTE can't be definitively diagnosed during life except in people with high-risk exposures. Researchers are currently developing diagnostic biomarkers for CTE, but none has been validated yet. When the symptoms associated with CTE occur, health care providers may diagnose traumatic encephalopathy syndrome.
Experts don't yet know how often CTE occurs in the population, but it appears to be rare. They also don't fully understand the causes. There is no cure for CTE.