dr. ann mckee is leading the charge in researching head trauma and the degenerative brain disease c.t.e. years looking at the post-mortem brains of hundreds of athletes who suffered concussions while playing their sport. this past summer, her findings shook the football world, when she discovered c.t.e. in the brains of 110 out of 111 deceased n.f.l. players-- raising serious concerns for those in the game today. and when dr. mckee autopsied patriots tight-end aaron hernandez, who killed himself after being convicted of murder, she found the most severe case of c.t.e. ever in someone under 30. now, she's seeing a similar pattern in deceased veterans who experienced a different kind of head trauma-- combat blasts. ( explosions ) of the 102 veterans brains dr. mckee's examined, 66 had c.t.e. i can understand a football player who keeps, you know, hitting his head, and having impact and concussions. but how is it that a combat veteran, who maybe just experienced a blast, has the same type of injury? >> dr. ann mckee: this blast injury causes a tremendous sort of ricochet, or a whiplash inju

dr. anne mckee. >> reporter: when dr. mckee autopsied patriots tight end aaron honored, who killed himself after being convicted of murder, she found the most severe case of c.t.e. ever in someone under 30. now she's seeing a similar pattern in deceased veterans who experienced a different kind of head trauma-- combat blasts. of the 102 veterans' brains dr. mckee's examined, c.t.e. how is it that combat veteran, who maybe just experienced a blast, has the same type of injury? >> this blast injury causes a tremendous sort of ricochet or a whiplash injury to the brain inside the skull. and that's what gives rise to the same changes that we see in football players, as in military veterans. >> reporter: blast trauma was first recognized back in world war i. known as "shellshock" poorly protected soldiers often died immediately or went on to suffer physical and psychological symptoms. today, sophisticated armor allows more soldiers to walk away from an explosion, but exposure can still damage the brain, an injury that can wors

dr. ann mckee, the chief neuropathologist at the boston v.a. s alfonsi they are similar to nfl's football field. >> reporter: when dr. mckee autopsied aaron hernandez who killed himself after being convicted of murder, she found the most severe case of c.t.e. ever in someone under 30. now she has seen a similar pattern in deceased veterans who experienced a different kind of head trauma, combat blasts. of the 102 veterans brains dr. mckee has examined, 56 had c.t.e. >> how is this it that combat veteran who maybe just experienced a blast has the same type of injury. >> this blast injury causes a tremendous sort of ricochet or a whiplash injury to the brain inside the skull and that is what gives rise to the same changes that we see in football players as in military veterans. >> reporter: blast trauma was first recognized back in world war i. known as shellshock, poorly protected soldiers offer be died immediately or went on to suffer physical and psychological symptoms. today sophisticated armor allows more soldiers to walk away from an explosi