New study reveals widespread signs of brain trauma among former NFL players

At least one in four NFL players has CTE when they die, according to a new study that examined the brains of former pro players. CTE is a brain disease thought to be caused by years of sustained head trauma and can only be diagnosed after an autopsy of the brain. Amna Nawaz spoke with Dr. Chris Nowinski of the Concussion and CTE Foundation, and a co-author of this study. PBS News is supported by -…