Former NFL players sue over brain injuries

BRIAN WILLIAMS, anchor: We have a follow-up tonight on former NFL star Junior Seau who killed himself with a gunshot wound to the chest on Wednesday. Today his family members agreed to allow his brain to be studied for signs that repeated concussions could have led to brain damage . This news comes on a day after more than 100 former NFL players filed suit against the league for the lasting damage that hard hits to the head may cause. Of course, this isn't limited to pro athletes. It's an urgent issue on every field, for every child and their parents during every contact sport . Our report tonight from NBC 's Kevin Tibbles .

KEVIN TIBBLES reporting: Hall of Famer Harry Carson played 13 years for the New York Giants . His opponent today, post-concussion syndrome.

Mr. HARRY CARSON (Former New York Giants Player): Once you're damaged from a neurological standpoint, you may never, ever be the same.

TIBBLES: Carson is one of a growing number of former NFLers battle brain injuries . Now more than 1500 of them are suing the league. The latest suit this week claiming the NFL failed to take reasonable steps to protect players from devastating head injuries . Away from the pros, efforts are under way to restrict rough contact between younger players.

Dr. JULIAN BAILES (Northshore University Healthsystem): We're going to limit the hours of the practice time where they can have any contact at all. And we're going to try to eliminate in practice any head-to-head contact.

TIBBLES: And at the NCAA level, in addition to recommending baseline brain scans, new guidelines mandate that if a concussion is suspected in any sport, athletes are pulled from a game until a qualified medical evaluation clears them for play. Some medical evidence suggested that three concussions may be the threshold when cognitive damage starts to occur. But that doesn't take into account the number of brain injuries a player may have sustained prior to turning pro. The NFL says it's working to protect players and advance medical understanding of the treatment of concussions, and in a statement said, "Any allegation that the NFL intentionally sought to mislead players has no merit."

Mr. CARSON: This is very much like being in the military and going to war, except you're fighting different enemies or different opponents week in and week out.

TIBBLES: And for many former players, that battle continues long after they've hung up their cleats. Kevin Tibbles, NBC News, Chicago.