Chronic Traumatic Encephalopathy (CTE) is a disease of the brain found in athletes, military veterans, and others with a history of repetitive head impacts. This type of trauma can trigger progressive degeneration of the brain tissue, including the build-up of an abnormal form of a protein called tau. The brain degeneration is associated with memory loss, confusion, impaired judgment, impulse control problems, aggression, depression, and eventually progressive dementia. A study recently conducted by the Department of Veterans Affairs and Boston University found CTE in 97 of 101 examined brains (post-mortem autopsy) of former NFL players. At present, the diagnosis of CTE can only be made through post-mortem examination of brain tissue.