Since 2008, researchers at Boston University School of Medicine (BUSM) and VA Boston Healthcare System have studied chronic traumatic encephalopathy (CTE), a progressive brain disease associated with repetitive head impacts that has been diagnosed after death in the brains of American football players and other contact sport athletes as well as members of the armed services. Clinically, impulsivity, explosivity, depression, memory impairment and executive dysfunction have been reported to occur in the disease.