CHICAGO (AP) Pro football Hall of Famer and former Heisman Trophy winner Paul Hornung is suing equipment manufacturer Riddell, saying its helmets failed to protect him from brain injury.

Attorneys filed the lawsuit on behalf of the 80-year-old Hornung in Cook County Circuit Court in Chicago on Thursday. It names Rosemont-based Riddell as the defendant.

The suit says Hornung suffered multiple concussions as a player and that he has been diagnosed with dementia. It says the neurodegenerative disease has been linked to repetitive head trauma. The suit seeks unspecified damages.

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Hornung won the Heisman in 1956 while at Notre Dame. The Green Bay Packers selected him a year later. He was the NFL MVP in 1962 and he played on four championship teams (1961, `62, `65 and `66).

Riddell didn't immediately respond to a request for comment.