GWEN IFILL: Next: the deadly toll of hockey's very hard knocks.
Jeffrey Brown has our story.
JEFFREY BROWN: His nickname was the Boogeyman.
Professional hockey player Derek Boogaard had one job: to be his team's enforcer, fighting and intimidating opposing players. It was his ticket to a life in the National Hockey League, his dream from childhood in small towns in Western Canada, and he was very good at it.
But years of punishment took a terrible toll, numerous injuries and concussions, eventually addiction to pain killers. And last May, just 28 years old, Derek Boogaard died of an overdose of medications and alcohol.
Researchers later determined he had a degenerative condition similar to Alzheimer's , caused by repeated blows to the head. Boogaard's story has been chronicled this week in a three-part series in The New York Times.
And we're joined now by John Branch, a sports reporter for The Times and author of the series, and Dr. Robert Cantu of the Boston University School of Medicine, one of the researchers who studied Boogaard's brain after his death.
John Branch, so this was a man who rarely, if ever scored a goal, couldn't skate fast, but was a crowd favorite and a kind of star in a particular way. Explain that role for those who don't follow sports.
JOHN BRANCH, The New York Times: Sure.
The enforcer is a guy who maybe doesn't have the greatest skills, but he's usually a big guy. And he treats -- he's treated basically as a bodyguard for the other team members. When they have -- if they start to get roughed up by the other team, they send out the enforcer. And that's kind of their bodyguard.
JEFFREY BROWN: And he, Derek Boogaard, told his mother -- you quote him -- when she was worried about all the fighting, she said, he said: "It's my job now."
This is really just part of hockey. Right?
JOHN BRANCH: He came to accept it. Yes, like most kids, he wanted to get to the NHL, and he wanted to do it by scoring goals. And at a certain time, when he was about 15 years old, he realized he didn't have the talent to make it to the professional levels.
And some scouts discovered that, you know what, if you are willing to fight and can absorb the beatings, and if you can do it well and you're willing to do it, then there's another way you can get to the professional level. And that's what he did.
JEFFREY BROWN: Now, you describe such a painful fall for him, through drug abuse, depression. And he chronicled much of that and much of his life in notes that you found -- were found after his death, right? Tell us a little bit about what was -- what -- the man that you found, I guess, through the writing.
JOHN BRANCH: Yes, his writings really were over -- really covered his childhood.
And so he had written down a couple of years ago about 16 pages worth of his memories about his childhood. And they're obviously very telling. They're very honest. And for somebody who was seen as this big tough guy on the ice, they're very tender in a lot of ways.
And he described, you know, the back-and-forth to hockey games with his dad. His dad was a Mountie in Saskatchewan. And they would drive in the patrol car across these icy landscapes to practices and games and so on. And he described really as he got older kind of the rough-and-tumble ways of hockey in Western Canada.
JEFFREY BROWN: Now, Dr. Cantu, I want to bring you into it.
When Boogaard died, his family donated his brain to your clinic for study. And you and your colleagues found something called CTE. Now, tell us a little bit about what that is.
DR. ROBERT CANTU, Boston University School of Medicine: Chronic traumatic encephalopathy, or CTE, is a progressive neurodegenerative disease that's associated with brain trauma, not just at the concussion level, but all brain trauma. So, sub-concussive blows are equally important.
It shares with Alzheimer's disease many similarities, including the deposition of an abnormal protein, a hyperphosphorylated form of tau. But the location of the tau is different in Alzheimer's than it is in CTE. And Alzheimer's has a great amount of beta-amyloid deposition, and tau -- and CTE does not. So there are clear distinctions.
JEFFREY BROWN: And in the articles, Dr. Cantu, one of your colleagues is quoted as expressing great surprise as what she found, what you all found with Derek Boogaard's brain.
Explain the importance of his case in the context of others that you have seen.
DR. ROBERT CANTU: Well, I think it's important to understand that, at the Center for the Study of Traumatic Encephalopathy, there are four co-directors, of which I'm one.
But the individual who actually studies the brains that are seen in the brain bank, which is just one function of the center, is Dr. Ann McKee. And Dr. Ann McKee found and her team found this hyperphosphorylated tau protein. Derek's brain had it in not an extreme degree, a mild degree of it, but definitely had it. So he definitely had this abnormal protein in his brain. And, therefore, the diagnosis of CTE could be made.
JEFFREY BROWN: But he had it at a very young age.
DR. ROBERT CANTU: Well, that's the real concern.
Reggie Fleming -- three of the four National Hockey League players that we have studied that have had CTE have been enforcers. The fourth one, Rick Martin, wasn't 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 have 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.
JEFFREY BROWN: Now, John Branch, you quote in your story the NHL commissioner, Gary Bettman, saying that it's too early to draw direct conclusions about a direct link between hockey violence and CTE.
Is that the state of understanding or acceptance of this -- these links that you find in sports generally? Tell us a little bit about that.
JOHN BRANCH: Sure.
It's actually very similar to what the reaction was from the NFL a few years ago from the same sorts of research from Dr. Cantu and the others. The NFL, I'm sure Dr. Cantu would say, is -- was pretty dismissive about the research for a long time as well. And it took a few more cases for the NFL to kind of come around and decide that this was a serious thing and needed serious attention.
The NHL has not reached that point. I think the question floating out there is, how many more cases need to come forward before the NHL decides to take it a little bit more seriously?
JEFFREY BROWN: Dr. Cantu, what do you find, and what is it that you think should be done to avoid more head trauma in sports? You see -- you do see more attention to it certainly in football these days, but what do you think needs to be done generally?
DR. ROBERT CANTU: Well, Jeff, I agree completely with everything John just said in terms of the differences between the National Football League, who does get it, and the National Hockey League, who I hope is on the way to getting it.
It is interesting, though, that these three out of four that have all been enforcers and have had a robust fighting career, the first descriptions of chronic traumatic encephalopathy were in boxers over 80 years ago by Harrison Martland. So, it's not a great surprise to find this fighting on ice and boxing kind of making it very likely that that's where they got their brain trauma.
Now, that's not to say that's the only place they got it, but, clearly, that's where they got a tremendous dose of it. I think what we need to do is to take all the unnecessary brain trauma out of sports. So practices should have less hitting, and certainly rules need to continue to be changed.
We have seen over 10 rule changes in the National Football League in the last year-and-a-half, all taking head trauma, reducing the amount of head trauma the athletes are seeing. And I think we have to see that in the National Hockey League as well.
JEFFREY BROWN: All right.
Dr. Robert Cantu and John Branch, thank you very much.
And, congratulations, John, on that series.
JOHN BRANCH: Thank you.
DR. ROBERT CANTU: Congratulations.