Learn about the damaging short-term effects of concussions suffered by professional football players, through the story of Dallas quarterback Troy Aikman, in this video from FRONTLINE: League of Denial. During the 1994 NFC championship game, a defensive player's hit to Aikman’s helmet knocked Aikman out of the game. In the hospital, Aikman was visited by his agent, who had to repeatedly explain what had happened in the game. For background, watch Introduction to CTE and review How CTE Affects the Brain. This resource is part of the FRONTLINE Collection.