CNNW Sanjay Gupta MD January 21, 2012
at for more than a year now. growing evidence repeated blows to the head, the kind you get on the football field can have lasting rep recushions. a law take effect in california. a player who gets a concussion must be cleared by a trainer or doctor before going back on the field. the risk is hard to gauge. you can't see damage to the brain unless you actually look inside. of course by then, it's too late. football is a violent game, full of big hits. what are all those collisions doing to the brain inside the helmets? i met with kevin, he's a researcher from the university of north c...