87 of 91 Deceased NFL Players Whose Brains Were Examined Had CTE, But What Does It Mean?

According to a new report from PBS’ Frontline, 87 of 91 deceased player’s brains that were studied at Boston University show signs of CTE (Chronic Traumatic Encephelopathy). Frontline, as you will recall, put together the documentary on the NFL and brain injuries, which ESPN pulled out of at the last minute. Researchers at Boston University, including Ann McKee, have been at the forefront of the CTE issue.

But what does this number mean? Here’s what it does NOT mean: that 96% of retired NFL players have CTE. Here’s what the article says:

"But the figures come with several important caveats, as testing for the disease can be an imperfect process. Brain scans have been used to identify signs of CTE in living players, but the disease can only be definitively identified posthumously. As such, many of the players who have donated their brains for testing suspected that they had the disease while still alive, leaving researchers with a skewed population to work with. "

To put this another way, it’s almost entirely people that have the major signs and symptoms of a significant brain injury (or their families) asking that their brains be studied posthumously. And in those cases, the testing of the brain is showing that in an overwhelming number of cases, there were physiological changes to the brain that can be detected.

It’s a similar issue to when I talked to researchers about the study of former NFL players, cognitive deficiencies, and age of participation in youth football. The sample is going to be biased because people who suspect they have issues are going to be more receptive to reaching out and investing their time to be studied.

Another claim that needs to be pointed out in the piece:

"Forty percent of those who tested positive were the offensive and defensive linemen who come into contact with one another on every play of a game, according to numbers shared by the brain bank with FRONTLINE. That finding supports past research suggesting that it’s the repeat, more minor head trauma that occurs regularly in football that may pose the greatest risk to players, as opposed to just the sometimes violent collisions that cause concussions."

I don’t think that it’s a new issue to say that concerns about the repeated sub-concussive hits that a player can take could be at issue. We’ve known for many decades that boxers who took repeated blows to the head could develop cognitive issues. However, that 40% number? I’ll point out that on a typical starting lineup, the offensive and defensive linemen make up around 9 of the 22 starters. That’s 40.9% of the people on a field. I’m not sure that piece of evidence alone is supportive that the guys in the trenches are a bigger risk factor. Most of the recent prominent suicides involving former NFL players, from Junior Seau to Dave Duerson to Ray Easterling, have been defensive backs or linebackers, not linemen.

So I’m not sure what to make of the current state of affairs. We are just entering a wave of players aging who started playing when the sport was becoming bigger, faster, stronger in the 1980’s. Who knows what the next decade will show. The incidence rate in the general population of retired football players is not as high as that number above. That said, it’s most likely well higher than the general population of people at the same age. We saw Chris Borland walk away preemptively from a NFL career because of concerns about his future, while still relatively healthy.

Just as importantly, parents around the country will make decisions much earlier, and they won’t require 30 years of data and clear evidence as to what that percentage is before making hard choices.

[image via USA Today Sports Images]