Police sources told ABC News the New York City shooting suspect had a note in his pocket claiming he suffered from CTE. It has not been confirmed if he had the condition. CTE, or chronic traumatic encephalopathy, can only be diagnosed after death through an autopsy. The degenerative brain disease is caused by repeated head trauma and is often seen in contact sports such as football, boxing and hockey. The CEO and co-founder of the Concussion Legacy Foundation says it's "becoming more and more of