BOSTON (AP) -- Michael Keck played just two years of college football before he was knocked out during practice at Missouri State and gave the sport up for good.
He turned combative - punching holes in the wall. He began to struggle in school. Soon he was spending most of his time indoors, with blankets covering the windows to darken the room.
Keck died last year at age 25 of what doctors believe was an unrelated heart condition. His brain, at his request, was donated to the Boston University lab that has been researching a degenerative brain condition frequently found in contact-sport athletes.
The disease, chronic traumatic encephalopathy, had advanced to a stage never before seen in someone so young.
''When you talk in terms of his age, being young, and you talk about his limited years of playing, it is one of the more severe cases,'' said Dr. Robert Cantu, a co-founder of the CTE Center at BU. ''Had he lived to 70 or 80, we would have expected this to be a Grade 4 (the most severe form) case.''
A star high school linebacker who first went to Missouri before transferring to MSU in 2009, Keck was knocked unconscious during his first fall camp with the Bears.
''After that, things changed for him,'' his wife, Cassandra Keck, said in a recent interview with The Associated Press.
Keck began forgetting the play call. He had vision problems. He couldn't sleep. He began taking medication for head pain. And his personality changed: He was moody, sometimes violent and depressed.
''He told one of the trainers there's something wrong with his head. They gave him a concussion test and told him to count backward from 20 by threes,'' Cassandra Keck said. ''Some other players couldn't do it, either. So they just said football players are dumb.''
Missouri State spokesman Rick Kindhart said the school's process for treating athletes with suspected head injuries was - and is - ''consistent with the current national standards of care.''
''MSU's athletic training and medical teams work diligently and responsively in each case to ensure all student-athletes receives appropriate care and attention,'' Kindhart said. ''No student-athlete is ever cleared to return to practice or competition without first being free of concussion symptoms and then going through the appropriate return-to-activity progression process.''
Cassandra Keck, who was pregnant at the time, said coaches told Michael that he was just stressed out because of the baby, a boy who is now 3 and named Justin.
But Michael Keck knew he wasn't all right.
''I think, if he had it his way, he'd still be playing,'' associate head coach D.J. Vokolek told the student newspaper, The Standard, when Keck left the team in March 2011. ''But it had gotten to the point that he was having so many concussions that it could affect him the rest of his life. After consulting with the doctors, we came to the conclusion that it was time for him to call it quits.''
Things only got worse.
''When he stopped playing, he became the bad seed,'' Cassandra Keck said. ''If they drank together, there ended up being holes in the wall. The next few years, people stopped coming around. People didn't want to be around him anymore.''
Unable to read without debilitating headaches, Keck left school six credits shy of graduation. Cassandra Keck said the suicide of former San Diego Charger Junior Seau, who shot himself in the chest to preserve his brain for study, ''really opened my eyes, because that's what Michael was going through.'' Seau was found to suffer from CTE, which can be diagnosed only after death.
The Kecks had just moved to Colorado, to see if the change would be beneficial to Michael's health, when he was hospitalized for a bacterial infection.
''I walked in and I saw him and I saw all the machines. All of a sudden I told this doctor in front of me, 'If he's not going to get through this, I want to donate his brain to Boston University because that's what he wanted to do,''' Cassandra Keck said. ''That was something he would tell me: He never thought suicidal thoughts ever, but sometimes he would say 'Sometimes I wish I would just die so I could donate my brain to Boston University to prove that there was something wrong with me.'''
Cantu said the worst cases of CTE are found in those who play for years, taking hundreds or thousands of hits to the head. It is progressive, so ex-players continue to deteriorate after they retire.
But Keck didn't play all that long, and he was too young for the disease to be blamed on aging.
Cassandra Keck said she was shocked to hear the diagnosis, but relieved all the same.
''You would hope that there was something wrong, for him to be suffering like that. The whole time I was with him, he was suffering from this,'' she said. ''All the time we'd talk about it. All the time we were doing research, so he could have a quality of life; so that Justin wouldn't grow up with his dad freaking out all the time.
''It makes me happy for him because it's what he wanted to prove to everybody,'' she said. ''He was really suffering, and nobody believed him.''