Barbara Howard:  We've heard about brain injuries and NFL players, but what about the effects on casual players who once took to the football field? For Dr. Robert Stern, a researcher at Boston University’s Chronic Traumatic Encephalopathy Center, the question is personal. He spoke with WGBH News telling how, as a proud father, he once enjoyed the camaraderie of the sidelines at Needham High School as he watched his own son play varsity football.

Stern: That sons’ friends today, some of his closest friends are from those football days. I didn't know about this stuff then. He wouldn't have played. But no one really knew about this stuff then. This is all new. And, here's the problem. Everyone talks about concussions. It's concussion this, concussion that, and therefore, there can be concussion protocols that every high school, there can be baseline testing with these computer testing ahead of time. There's laws in every state in the country now for return to play, and that's great.

But when it comes to the long term stuff, it's not concussions that are the issue. It's the repetitive hits, over and over and over again. If we focus on the bigger, more important issue, that the game has an inherent problem, the very nature of the way the game is played involves hitting heads over and over and over again, you can't take that out of the game. You can do something about concussions, and so it's in the NFL’s interest to focus on concussion because they can do something about it. They can count them. They can make changes to rules, and they can tell the world that they're doing something to protect players brain health. There can be new programs for learning how to tackle in youth football that are out there to help prevent concussion, but they’re still wearing those big helmets. You don't feel pain when you hit someone or when you fall on the ground.

Howard: But your brain sloshes around.

Stern: Your brain sloshes around every time …  I'm disturbed. I'm surprised that no matter what, the focus always keeps going back to concussions. And I'm hoping that parents and others can understand that when it comes to the long term consequences, concussions aren't the only issue.

Howard: Do you see football as a public health issue?

Stern: I do. Well, it's a public health issue because of the numbers of people who may have long-term impairments due to playing. And those numbers, I'm afraid, of what they might be as we move forward. Here's something to contemplate: I've asked the question, has there ever been any activity that human beings have done that has included repetitive head impacts over and over again? The answer is no, not until very, very recently. That repetitive hit, that's something new. It really wasn't until the 1950’s that human beings started to hit their heads over and over again so repeatedly. And that was in two sports. One in boxing and the other football.

American football has been played since the 1800s, but it wasn't until the mid 1950s that the large plastic helmets started to be used. And that changed the game. It did something that people don't think about a lot. It allowed them to just hit their heads without hurting, over and over again

Howard: Because the brain really doesn't have any nerve endings?

Stern: The brains don't have any nerve endings. And you have this big encasement so you're …

Howard: So you don't even realize that your brain is getting banged around.

Stern: Of course not. And so when you think of it, people who played tackle football in high school or in college in this new era of big helmets, they're in their 70s now. And the folks who started playing tackle football as kids, the earliest, are only in their late 50s and early 60s now. So we may have not even seen anything yet. Because there's been millions and millions of people who’ve played tackle football in this new era since the 1950s and 60s who started playing as kids. And they're only getting to the age where a degenerative brain disease would start being manifest in large numbers.

I certainly hope that I'm wrong, but that's a public health issue.

Howard: Thanks so much for coming in.

Stern: You're very welcome.

Howard: That's Dr. Robert Stern of Boston University's Chronic Traumatic Encephalopathy Center.