Chronic Traumatic Encephalopathy (CTE) is a progressive degenerative disease of the brain found in athletes and others with a history of repetitive brain trauma, including concussions and even sub-concussive hits to the head. This disease was previously called dementia pugilistica (DP), or “punch-drunk,” as it was initially found in those with a history of boxing. CTE is now most commonly found in professional athletes participating in football, ice hockey, professional wrestling, stunt performing, bull riding, rodeo, and other contact sports resulting in repetitive brain trauma.

In 2015, researchers from the Department of Veterans Affairs and Boston University announced that they had identified CTE in 96 percent of the 91 deceased NFL players they had examined and in 79 percent of all football players. CTE often results in symptoms of dementia, such as memory loss, aggression, confusion and depression, which may appear years—or even decades—after the trauma.