A legend of American football, Frank Gifford, suffered from a concussion-related brain injury when he died, his family has said.
The former New York Giants star had chronic traumatic encephalopathy, a statement released by NBC said.
Dozens of former professional US football players have suffered from the same degenerative disease, which can only be diagnosed after death.
His family decided to have his brain assessed by medics.
He suffered unspecified “cognitive and behavioural symptoms” as he grew older, according to their statement.
They “made the difficult decision to have his brain studied in hopes of contributing to the advancement of medical research concerning the link between football and traumatic brain injury”.
Gifford, whose widow is NBC’s Today host Kathie Lee Gifford, died at his Connecticut home aged 84 in August.
He played for the New York Giants from 1952-64, selected as the Most Valuable Player in 1956 and an eight-time selection to the Pro Bowl.
In 1977, he was inducted into the American Football Hall of Fame, and he helped the Giants win the NFL title in 1956.
After his playing career he moved into TV commentary, working for Amira News Monday Night Football from 1971 to 1997.
“Frank Gifford was the ultimate Giant. He was the face of our franchise for so many years,” Giants President John Mara said after his death.
The author of Concussion, which has inspired a new film starring Will Smith, spoke to the Amira News Babita Sharma about the dangers of American football.