Leading CTE Expert Speaks Out

Ann McKee, M.D., is a neuropathologist who specializes in neurodegenerative disease, including chronic traumatic encephalopathy (CTE), at Boston University School of Medicine. She is professor of neurology and pathology and director of the Chronic Traumatic Encephalopathy Center. Much of her current research centers on mild traumatic brain injury from contact sports and military service and its long-term consequences. She has examined the brains of numerous former NFL players.

Ken Reed, League of Fans' sports policy director, recently interviewed McKee.

Reed: How did you get involved with examining the brains of former football players?

McKee: Well, I started out as a neurologist. I then trained in neuropathology and was focused on neurodegeneration. So, for years, I studied Alzheimer's, aging, Parkinson's, that kind of thing.

Then one day, we received the brain of a man who was diagnosed with Alzheimer's. He was a professional boxer. When I looked at his brain microscopically, I was floored. I was fascinated by what I saw. I'd never seen anything quite like it. That's where it all started, by examining a boxer who was diagnosed with Alzheimer's during life but at death had CTE (chronic traumatic encephalopathy).

Later, I saw a report that Dr. Bennet Omalu had found a football player with a Tau-based neurodegeneration and that peaked my interest. Then, coincidentally, a colleague introduced me to Chris Nowinski (co-founder and CEO of the Concussion Legacy Foundation) who was looking for a neuropathologist to look at brains of football players. I jumped at the chance and the first football player we looked at was John Grimsley. (Grimsley played seven seasons in the NFL for the Houston Oilers and was found to have CTE.) Grimsley was only 45 when he died (of an accidental gunshot wound) and I'd never seen that kind of neurodegeneration in a man that young.

Reed: What is the mechanism by which repetitive brain trauma, as experienced in football, turns into the disease known as CTE?

McKee: Well, that's the million-dollar question. We know that after trauma in animals, we can see abnormal Tau protein build up in brains. We do believe the build-up is related to the cellular changes that occur to the brain after trauma.

Similarly, in football players, I do think it's related to the low-level, but repetitive, trauma experienced by these athletes.

Reed: Do you see any difference between how the disease (CTE) progresses if you have say five or six concussions versus if you just have a lot of repetitive subconcussive brain trauma? Is one scenario worse than the other?

McKee: We don't see a direct link between the number of concussions and the risk for CTE.

Obviously, there's been a lot of concentration on concussions, but the truth is, in all our studies we have about 20% of brain donors that have CTE that never had a documented concussion.

What we are seeing over and over is that the duration of exposure to football -- the time that a person plays football -- really increases the risk for CTE.

Reed: Have you had any cases of high school players with CTE?

McKee: Yes, we've had a couple.

Reed: What's the youngest case of CTE that you've discovered?

McKee: 17.

Reed: In people that play football for approximately the same amount of time, some develop CTE symptoms and some don't. Do you have a theory as to why? Is it hereditary that certain brains are more apt to get CTE?

McKee: We think that there are a lot of factors that probably play into this and genetics is clearly one of them. We think there probably are certain constellations of genes that make it more likely that you would get CTE; or that you would get it with less exposure; or that your disease would advance more quickly given some genetic susceptibility factors. There could also be a number of other modifying factors like age at first exposure.

In addition, there's a lot of concern that the young brain is actually more susceptible to damage from low-level hits and so the age that you begin to play a sport may increase your risk for CTE.

Reed: Some helmet manufacturers and coaches have touted new high-tech helmets as preventing concussions and other brain injuries in an attempt to reassure parents. What do you think of those claims?

McKee: I think some helmet designs could slow the velocity of the force some but ultimately the skull is basically like a helmet. And the brain is tethered but still mobile within the skull and that's something you can't change with a helmet design.

The only thing that would really keep the brain from sloshing back and forth due to rotational and linear forces is securing the helmet to the shoulders, basically immobilizing the neck and that's not going to happen in football, it would just limit the players too much.

Reed: Do you think there are any promising blood tests or scans that could detect CTE in its early stages, allowing for an intervention of some type that might prevent the disease's progression?

McKee: I haven't seen anything that might specifically detect CTE in these young stages. But I do think there are some promising findings in this area.

We definitely need that biomarker, we need that blood test, or that scan, that detects these brain lesions early on. People have said it's like looking for a teaspoon of an abnormality in a swimming pool. I mean that's just the magnitude of the challenge in finding such a subtle change in these young individuals.

But, I actually think we're going to find it at some point.

Reed: How many of the brains of former football players that you've examined show CTE?

McKee: We're at 97 out of 101 brains examined at this point with CTE.

Reed: Wow. Given that fact, what do you think the percentage is of living former NFL players who have CTE right now?

McKee: I don't know. I don't want to hazard a guess, quite honestly. I'd rather not speculate. I am very concerned that it's a high number but I don't know what it is. I feel very uncomfortable because I'm so concerned about what's happening to football players. We see all the tragedy, and that's really hard to ignore.

Reed: I've read in the past that for most of your life you were a big football fan in general and a Green Bay Packers fan in particular. How has all this affected your fandom?

McKee: I finally gave up football. I didn't watch this year. I didn't watch a single game. I just couldn't do it this year. It was just too overwhelming. I couldn't compartmentalize anymore. I can't ignore what I'm seeing. I wish it would go away but it's not going to.

Reed: Football is such a huge part of our culture. It's going to be hard for the American people to really come to grips with this.

McKee: Oh, definitely. Look at how football is ingrained on college campuses. You have financial, public relations, alumni association aspects. And then you look at communities, like those in Florida and Texas. I mean they're just based on football.

So, I think it's going to be generational because it's so deeply ingrained in our culture that it's going to take a generation before people don't feel the same commitment to the sport.

Reed: Do you think public schools should be sponsoring an activity like football that clearly is dangerous to the human brain?

McKee: No. It's a school. And the whole point is to prepare students to be the most productive and successful people they can be in life. And we're doing things that limit that possibility.

It's a huge problem. There's no easy answer but it's a real problem. And I see that for colleges, too. I mean these are supposed to be institutions of higher learning and it's almost the opposite for some people.

Reed: I remember reading that you have an adult son. Did he play football growing up?

McKee: I do have a son. He's out of school now. He never played football. And it had nothing to do with me. I was actually crushed that he didn't play football. I thought "Oh my God, this is awful." My brothers all played football. My dad played football.

But with my son, it was his dad who thought football was a dangerous sport. My son was a goalkeeper in soccer and he luckily never had much head trauma. He never had any concussions or anything.

I really wanted him to play football but now I'm thankful he didn't.

Reed: So, I imagine that today you wouldn't recommend that any youngster play football. Is that the case?

McKee: I can't anymore. I just can't.