dr. ann mckee has made it her life's mission to understand why some players are susceptible to cte, and others are not. she's a director of the vacste brain bank. it's a joint project between the veterans administration and western university. you're starting to see some of those same types of changes in people that are younger as a result of -- >> of repetitive trauma to the brain. it's not the same distribution. and it doesn't affect the same parts of the brain, but we do see some characteristic shrinkage. >> reporter: what we're seeing here, is this definitely caused by blows to the head? >> it's never been seen in any reported case except in a case of repeated blows to the head. >> reporter: i think the remarkable thing is how early in life some of these changes can start to take place. what's the youngest that you've seen some of these early signs of what people are calling cte or sort of a dementia-like thing? >> the youngest case to date is a 17-year-old. >> reporter: the brain of nathan styles. >> which is nathan styles, right. >> reporter: for nathan styles, 2010 was supposed to be hi

dr. ann mckee, director of neuropathology core bu alzheimer's disease center, i guess that's boston university, and dr. mike oliver, director of the national operating committee on standards for athletic equipment. we welcome all of you, and i'll just close right there and ask if the chairman of the subcommittee would wish to say something because he's been just terrific on the subject and also the ranking member. go ahead. >> well, thank you, mr. chairman, again for us holding this very important hearing this afternoon. as a former player, it's something i'm interested in, but also, you know, there's so many moms and dads and coaches and players all across the country, you know, that are also very interested and probably should be more interested than what they realize, and i think that's the great thing about having this hearing is to try and get that information out and really discuss a potential, very serious problem, not a potential very serious problem, but a very serious problem, period. sports play a role in the development of young men and women, build youth, social relationships, and

dr. ann mckee. many questions remain as to the causes and effects. i am very interested in hearing what is known and where we go from here. there is also a wide variety of the athletic equipment on the market that claims to use concussion-preventing technology. parents want to keep their children protected, but navigating the many products and claims in the marketplace, especially online, can be overwhelming. it could be easy to read the something offers the best protection and assume that their child could be safe from injury. that is simply not true. some products offer better protection than others, but we need to explore what resources exist to help parents and coaches know what level of safety a product will lead to be provided. i also do not know how the average parent or coach can be confident that the equipment they purchase offers a better safety benefit, or if it's advertisement contains misleading or deceptive claims. i hope all witnesses will be able to answer this question. along with a knowing the safety of limitations of sports equipme

dr. ann mckee talked about anti concussion mouth guards. have you seen at such as this one for a mouth guard sold for use by kids 11 years and under and you can see the poster here in the background. this was purchased west month. the product packaging statement mouth guard reduces the risk of concussion and creates brain save the space. given your first hand knowledge, are you troubled by this type of marketing for used sports equipment. young athletes who had a concussion might be particularly susceptible to advertising claims for so-called anti concussion devices. >> there is no clear evidence that mouth guard or a chin guard reduces either the rate or severity of concussion so i would have great objection to this claim. the only thing i am aware mouth guards and shin guards do is reduce floral and facial and dental injuries. the nature of concussion is not improved by the use of a mouth guard. >> you were not able to see what i was holding up. just in case you see anything else you want to comment on. >> i agree on that. are don't know

dr. ann mckee, professor of neurology and pathology at boston university and director of arrow path allahalzheimer's disease center. and mr. mike oliver who is executive director of the national operating committee on standards for athletic equipment. we welcome all of you, and i will just close right there and ask if the chairman of the subcommittee would wish to say something because he has been just terrific on the subject and also the ranking member. go ahead. >> thank you mr. chairman again for holding this very important hearing this afternoon. as a former player it is certainly something i'm interested in but also there are so many moms and dads and coaches and players all across the country that are also very interested and probably should be marches did and what -- and what they realize and that is a great thing about having this hearing is to try and get that information out and really discuss a potential very serious problem. not a potential very serious problem, very serious problem period. sports place of vital role in the development of young men and women, help social relat

dr. ann mickie, a professor of pathology -- ann mckee, a professor of biology. i am also co-director for the center of dramatic encephalopathy. i am not speaking on behalf department of veterans affairs. mild brain injury, or concussion, is a temporary state of neurological dysfunction resulting from forces on the brain, acceleration, deceleration collateral and rotational forces. some of concussion is caused by these same forces, -- sub- concussion is caused by the same forces, but symptoms are milder. in all of these cases, the brain looks normal after the injury and there is no detectable damage on routine euro imaging, such as acy thank fdot -- such scan or mri. as the brain as a whole is stretched or deformed by these forces, there is also stretching on the support cells within the brain. the brain abnormalities associated with a concussion occur at the molecular and metabolic levels. if an athlete returns to play before the symptoms result, the athlete risks of developing post-concussion syndrome or cysts that are a rare, but often fatal, condition. in add