dr. julian bails says concussions can change forever the way the brain works. >> i'm of the opinion more and more that a concussion is not necessarily hitting your head, it's the movement of the brain inside the skull, which causes the tearing of the fibers. >> reporter: a hard hit can cause the rough edges inside the front of the skull to tear at the brain's fibers. and doctors believe that can lead to headaches, difficulty concentrating, balance and vision problems and even depression and suicide. dr. stanley hearing heads the nfl's head, neck and spine committee. >> if there is a suspicion of a concussion, stop player practice and don't return until you have medical clearance. >> reporter: that's the law in ten states already. now congress is considering a national law to protect players from the dangers of concussions. tom costello, nbc news, washington. >>> here in new york city today at a meeting of world leaders at the u.n., the united states, along with britain, france and five other countries, got up and walked out of the general assembly chamber over remarks made by the preside

dr. julian bails. what have we discovered?n what this is, doctor. >> this is inserting electrodes deep in the brain in the part that controls our appetite. our neuro surgeons have spearheaded this fda approved study to see if this possibly would have some benefit for patients with morbid obesity. the most severe forms. the one where their life expectancy will be affected. >> larry: how does it work? >> electrodes are placed on both sides of the brain. one into the part that makes you feel full and the other part is the appetite center where your drive to eat is. a pacemaker generator is inserted under the skin and we change settings and try to see if we can affect the appetite drive these patients have. >> larry: what have you learn sod falearned so far? >> the procedure can be done safely. we don't think we're having side effects and we can affect the urge to eat and decrease the urge. we're looking at it being well tolerated. the jury is still out. we don't have all of the results yet. we're working to refine the settings to

dr. julian bailes, has been called in. he's a man in the business of saving lives for more than two decades. >> this lady has a tremendously big blood clot. the aneurysm ruptured. she's in a deep coma. the only hope she has is that we can get the clot out. so, let's go in and cure her. the brain is undoubtedly the most complex structure on the face of the earth. it's the most precious real estate in someone's body, and something we work day and night to try to preserve or to alleviate suffering as much as we can. >> all right, yous be good. i love yous. >> kristy macdonald is a 30-year-old single mother. her seizures started just three years ago and are getting worse. >> right now, life is hell. >> contorting of the body and, you know, her head would just turn. i mean, almost like "the exorcist." it was really just that scary. >> hey, kristy. >> despite a daily regimen of medication to treat them, kristy's seizures are becoming more frequent. >> hey, kristy. you're all right. >> in a day, i'm not sure. maybe one every -- a