Former San Diego Chargers linebacker Billy Ray Smith has died aged 64, his family announced. They said he had endured dementia caused by chronic traumatic encephalopathy (CTE), drawing renewed attention to the long-term neurological risks associated with repeated head impacts in American football.

Smith was a College Football Hall of Famer and a top-five NFL draft pick. CTE is a progressive degenerative brain disease linked to repeated head impacts rather than one isolated injury, according to the Mayo Clinic; the family’s statement attributed Smith’s dementia to the condition.