dr. ann mckee. dr. ann mckee and her team found this hyper fos lated protein derek's brain had it not in extreme degree, a mild degree of it but definitely had it so he definitely had this abnormal protein in his brain. therefore, the diagnosis of c.t.e.could be made. >> brown: but he had it at a very young age. >> well that's the real concern. reggie fleming... three of the four national hockey league players that we've studied that have had c.t.e. have been enforcers. the fourth one rick martin was not an enforcer. he had a mild form of it as well. reggie fleming, who died at a much more advanced age, had a very extreme amount of it. derek was just 28. the youngest of those in the national hockey league that we've had a brain to study. and the very fact that he had it, even at this more mild form it's a progressive disease so had he lived to be in his 50s and 60s, it would have been expected to be much more severe. >> brown: john branch, you quote in your story the nhl commissioner gary betman saying t

dr. ann mckee in boston.you're one of the believers like i am in her work that indicates the protein, that's very important in the body for neurological, it seems like multiple blows to the head. i'm not a doctor. i'm a tanker, but what it explains it bends over itself and it collects in the brain and it has the effect of beginning to eat away at the brain. you all heard -- i think his name is brian doerson the chicago bears football player who committed suicide not too recently. most men put a bullet through the head. he put it through the chest. put it through his chest 'cause he wanted ann mckee to do the biopsy of his brain because he had a very successful nfl career, very successful in business, and then he started to display all the symptoms, early dementia, problems getting along with people, anger management issues. he killed himself. they looked at his brain and he had the same buildup of tao protein she's seen in just about every single case she's looked at in the nfl and it's also been studied in b