BOSTON (AP) — Former LSU and NFL football star Leonard Marshall says his football playing days left him struggling with short-term memory loss and erratic behavior.

On Wednesday, Marshall joined three-time Pro Bowl quarterback Matt Hasselbeck in pledging their brains to research.

The two retired football stars say they will donate their brains to the Concussion Legacy Foundation for research into chronic traumatic encephalopathy.

The announcements were made as part of the second annual Brain Trust conference, which is hosted by the Department of Veterans Affairs.

Marshall, 55, is a former New York Giants defensive lineman and two-time Super Bowl champion. He played at LSU from 1979 to 1982 and was inducted into the LSU Hall of Fame in 2008.

Hasselbeck's father, Don, was a teammate of Marshall's on the Giants and pledged his brain to the foundation in 2010.

More than 1,800 former athletes and military veterans have pledged to donate their brains to the Concussion Legacy Foundation for CTE research. The progressive degenerative brain disease has been linked to repeated head trauma.

In 2015, Marshall spoke about the dangers of concussions during a Louisiana coaches clinic. He said he displays the symptoms of chronic traumatic encephalopathy or CTE. He also said he was in the early stages of Parkinson’s disease.

CTE is a progressive degenerative disease that can only be diagnosed postmortem in individuals with a history of multiple concussions.

Marshall told coaches he carries a picture of his brain scan in his cell phone and joined former NFL players in their concussion lawsuit in 2011 after his friend, former Bears safety Dave Duerson, committed suicide.

Marshall has his own initiative on football safety,

“Do I wish I knew all the things we know now about concussions when I played? Sure,” Marshall said. “But I still think football is a great game. It just has to be approached the right way.”

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