No true changes can be made. It's believed that a lot of CTD is not the result of concussions but the cumulative effect of non-traumatic plays that involve collisions, especially on the line of scrimmage. Objects in motion tend to remain in motion, especially brains suspended in fluid. No helmet can prevent brain injuries caused by 300 pound men moving forward with great speed until they meet resistance and suddenly stop.

Never thought about it before but these guys are the modern equivalent of gladiators. Nobody is dying on the field but their life expectancy is reduced significantly by how long they play.