Four former NFL players have filed a federal lawsuit  claiming brain injuries have left them with medical problems years after their playing days were over.

Jamal Lewis, Dorsey Levens, Fulton Kuykendall and Ryan Stewart recently filed the lawsuit in U.S. District Court in Atlanta against the National Football League and FNL Properties LLC. The players allege that the NFL knew as early as the 1920s the harmful effects concussions could have on players and that the league concealed those dangers from coaches, trainers, players and the public until June 2010.

The four former players claim medical problems that stem from their days on the field include memory loss, headaches and sleeplessness. They are asking for a jury trial and an unspecified amount of damages.

The NFL said that it has long made player safety a priority and does so to this day. “Any allegation that the NFL intentionally sought to mislead players has no merit,” the league said in a statement to the Associated Press.

If you or a loved one is suffering the effects of a football related concussion, contact Texas injury attorney David Buckley.