Why a leading neuroscientist wants the brains of hockey players

Neuroscientist Dr. Charles Tator has asked the family of former NHL enforcer Todd Ewen to donate Ewen's brain so he can study it. This week, Ewan's death was ruled a suicide and Tator wants to examine his brain to determine whether it has signs of degeneration. In particular, he's interested in what Ewen's brain may have in common with the other brains of athletes he's studying as part of the Canadian Sports Concussion Project.

Brent Bambury speaks with Dr. Tator about how concussions can affect athletes and what big unanswered questions remain when it comes to the links between concussions, brain injury and self-harm.

This conversation has been edited for clarity and length.

Brent Bambury: You and your team already have examined the brains of eighteen former professional athletes. What do you hope to learn by looking at Todd Ewen's brain?

Dr. Charles Tator: Well we want to know if he had C.T.E. In other words, was this the cause of his decline in terms of depression, for example.

BB: What is C.T.E. ?

CT: Well C.T.E. is chronic traumatic encephalopathy which is a specific type of brain degeneration that occurs after repetitive trauma like multiple concussions.

BB: Is that something that you can only determine by examining the brain from a cadaver?

CT: Unfortunately, even though we are getting clues about it from other tests like M.R.I., at this point in 2015, you have to do an autopsy to be sure that it's C.T.E. So with the Todd Ewen donation, if we're fortunate enough to have that opportunity to examine his brain, we would want to see if there were any manifestations of these previous concussions that he had in his career.

BB: You have approached the family with your request for Todd Ewen's brain and I would imagine that that's a difficult thing to do. How do you approach the family when you're trying to bring them over to your research?

CT: Well that's a very good question and yes you're right it is very difficult, very delicate. I mean these are often terrible circumstances in which their loved ones find themselves and so we try to approach it with extreme care. Fortunately a lot of these people have actually discussed this beforehand with their loved ones and have given instructions that "you know when my brain is ready for examination post-mortem, please send it to so and so."

BB: Well in the case of Mr. Ewen he was battling depression and and you've been researching whether there is a connection between repeated blows to the head and the likelihood that someone may commit suicide. What have you found?

CT: One of our recent findings --  which is on the basis of M.R.I. imaging so this is an in-life test that we can do safely --  we actually could detect white matter damage in a tract in the brain that has something to do with inhibition. And damage to this tract may make players more susceptible to doing impulsive things like the act of suicide. That they may not be able to inhibit the thought of suicide.

BB: So in the case of Todd Ewen, who reportedly died of a gunshot wound to the head, if the brain is damaged will you still be able to use it for research purposes?

CT: We hope, yes. If it's a low caliber bullet for example it would only do local damage that the tract of the bullet would not be useful for determining the presence of C.T.E. but the rest of the brain would be useful. So we're hoping that that's the way it's going to turn out.

BB: Not every athlete who experiences repeated blows to the head develops C.T.E. Do we know why that is?

CT: We do not know why one athlete gets it, and another doesn't. We don't know if it's something in the genes that that particular family is carrying because we do know that there are some pretty famous families where they've all been concussed. But it may be some other factor. It may be inflammation or it may be degeneration of nerve fibres that was going to happen anyway like Alzheimer's disease for example. So at the present time we don't know why one gets it and another doesn't and in fact in our own series, only about half of the athletes that we have examined the brains of have had this condition.

BB: In the case of the N.H.L. Commissioner Gary Bettman has continued to dispute that there's a link between repeated head trauma and brain disease. What do you think of his position?

CT: Well, I would say the linkage is getting stronger by the minute and it's not just us and our research center, but it's the whole world is looking at this problem. This has become a very hot topic in research. Because you know not only the the professional athletes are at risk here but what about all the kids who are getting repetitive concussion. I've seen several youngsters like even at the age of 13 who have already had three or four concussions and who are symptomatic. Like with headaches and inability to concentrate and their marks are going down and they can't sit in front of a screen et cetera. So we're seeing a lot of people who are disabled by concussions.

BB: Dr. Tator do you watch hockey, are you a fan?

CT: I love hockey. I played hockey in high school and in university. I had my picture taken with Teeder Kennedy, Syl Apps, George Armstrong, people you don't even know who they are, I'm sure.

BB: [Laughs] I know those names, I'm a Canadian too, but are you an advocate then for less violence in hockey? 

CT: You know what, I love the game of hockey but I don't like to see the violence because as a brain surgeon I know what that violence leads to. And it will survive well if we eliminate the violence. You might have a different audience that you're appealing to but those are really a minority. The majority of people would definitely support reduction of violence in hockey.