Brain Injury in Sports, Past and Present

From the lecture series: The Skeptic's Guide to Health, Medicine, and the Media

By Roy Benaroch, M.D., Emory University

Brain injury in sports has long been an issue, but we’re just now realizing the repercussions. Should we be encouraging sports that might leave our children with debilitating neurologic illnesses?

Brain damage and sports injury concept with damaged brain model, american football helmet and a ball
(Image: Victor Moussa/Shutterstock)

Did Lou Gehrig Really Die from “Lou Gehrig’s Disease”?

On the Fourth of July, 1939, Yankee Stadium was packed with 61,808 fans. They were there to say farewell to Lou Gehrig, aka “The Iron Horse.” He had put on his pinstriped uniform that day for the very last time.

The Yankee’s first baseman had played in 2,130 consecutive games—a record that stood for over 50 years. On that day, two weeks after he turned 36, he called himself, “The luckiest man on the face of the Earth.”

He died less than two years later.

This is a transcript from the video series The Skeptic’s Guide to Health, Medicine, and the Media. Watch it now, on The Great Courses Plus.

The Iron Horse was more than just sturdy—he was a fantastic baseball player. He had seven consecutive All-Star appearances, played for six World Series champion teams, and had a career .340 batting average. He is still considered one of the best first basemen to ever have played the game.

But that Iron Horse side of him, the durability and grit—the stories are incredible. Nothing could stop Lou Gehrig.

Gehrig with the New York Yankees in 1923
Henry Louis Gehrig was a first baseman for the New York Yankees from 1923 until 1939. (Image: Pacific & Atlantic Photos, Inc/Public domain)

In 1933, a pitch hit his head, nearly knocking him unconscious, but he stayed in the game. A year later, he was out cold for 5 minutes after another pitch to the head, but returned to play the next day.

Back then, there were no batter’s helmets. And it wasn’t just head trauma—X-rays taken later in Gehrig’s life revealed numerous fractures that had occurred during his playing career—but they never kept him out of a game.

What finally knocked him out of baseball was a rapidly progressive neurologic disorder that robbed him of his speed and strength, leading to his death at age 37. The illness was diagnosed as Amyotrophic Lateral Sclerosis (ALS), which has become popularly known as “Lou Gehrig’s disease.”

But, what if I told you that the progressive neurologic deterioration that led to the end of the Iron Horse was something else entirely?

In 2010, a group of researchers showed that repetitive head trauma could be associated with damage to the motor nerves, resulting in symptoms identical to ALS. In fact, since 1960, 14 former NFL players have been diagnosed with ALS.

Now, ALS is a rare disorder, and statistically we’d expect only about two NFL players to have ALS across that many years. In this small sample, ALS is diagnosed seven times as commonly in NFL players as compared to the general population.

What if at least some of these cases aren’t ALS at all, but a mimic related to repetitive head trauma during a player’s career?

Now, we don’t know for sure whether Lou Gehrig had what’s now known as chronic traumatic encephalopathy, or CTE. His body was cremated without an autopsy, and an effort to unseal his medical records has failed.

Learn more about how two antithetical headlines can result from the same scientific report

Brain Injuries and the Future of Sports

No matter what happened to Lou Gehrig, many professional athletes, as well as amateur, college, and weekend athletes, are suffering from brain injuries that will have long-lasting repercussions.

There are some big decisions here: decisions about sports and society and the long-term effects of not only football and baseball, but lacrosse, soccer, and just about every other active sport.

We know that sports participation in our neighborhoods and schools offer real benefits. But what’s the balance, here?

Families and communities need good, solid information to help decide whether to build a youth football stadium, what kind of helmets to buy, or which sports to fund and support. Should we be encouraging sports that might leave our children with debilitating neurologic illnesses?

So how do we get this information?

We all rely on the media to tell us what we need to know. And by media, I mean the news, of course: the traditional news including TV, newspapers, and magazines, but also the new media of Facebook and the internet.

The problem isn’t that we lack medical news and information—in fact, we are, in many ways, drowning in it. The problem is that what’s being presented is not always reliable or useful. Sometimes, it isn’t even true.

And this is important. The body of what we know and understand is growing daily. The decisions we make about health—about how to prevent and treat head trauma like concussions, for instance—are crucial to every family.

False information leads to bad decisions, which in health care can have deadly consequences.

We should be aware of this potential media bias when focusing on brain injuries, through the lens of sports-related injuries.

Learn more about the dark side of medical publishing

The Two Types of Brain Injuries

Broadly speaking, there are two kinds of brain injuries. One is obvious, associated with major trauma or a stroke, with physical damage to the brain itself that you can easily see on a CT scan.

Most sports injuries, though, fall into the second category. These are subtle injuries, sometimes called minor head trauma or “concussion,” and can be overlooked at the time of the initial event, but which can have lasting and very serious consequences.

So, why do these kinds of injuries occur? The brain is encased in the skull, a sort of built-in rigid helmet. There’s a small space, three to five millimeters, between the brain and skull, which is filled with fluid and membranes that provide some cushioning.

magnetic resonance image (MRI) of the brain
MRI image of a brain showing the brain encased in the skull with a thin membrane in between them (Image: MriMan/Shutterstock)

Now, imagine this: The head is struck, hard, and it accelerates quickly away from the blow. The brain, inside the head, doesn’t move immediately—it stays in place, because of momentum, and ends up slamming into the inside of the moving skull.

Or, imagine the opposite scenario: Let’s say a motorcyclist is riding at 60 miles per hour. That means his head and his brain are both traveling at the same speed. If he strikes a tree, his head and his skull very rapidly decelerate and stop moving. But his brain’s momentum carries it forward, and it slams into the inside of the skull.

The physics works out the same, whether it’s a sudden deceleration or acceleration—change the movement of the head quickly enough, and the outside of the brain is going to hit bone, and it’s going to hit it hard.

This kind of mechanism is important, and it does happen, essentially bruising the outside of the brain. But, there is a much bigger problem in this scenario.

Learn more about concussions and the future of football

Why Are Concussions So Damaging?

The brain is not a rigid thing, like a bone—it’s not even firm, like liver. It’s kind of soft, more like the substance of jelly. And it’s made of about 100 billion cells, with trillions of interconnections between these cells, like a fabulously complex 3-D spider web.

When the brain is suddenly jarred or moved—especially if that movement includes rotation or twisting, say from a blow to the side of the head—the tissue twists and stretches, like you’d imagine a blob of jelly suddenly thrown in the air.

The nerve cells themselves are stretched, or pulled away from each other, which causes a chaotic release of neurotransmitters along with an uncontrolled depolarization of each cell’s electrical charge. The cells can’t communicate with each other, and they’ll need a lot of energy to repair, rebuild, and reestablish normal physiology.

Brain Damage Illustration showing the nerve cells in a healthy and a damaged brain.
When the brain is suddenly jarred, the nerve cells themselves are stretched causing damage (Image: joshya/Shutterstock)

If they can’t get that energy, some cells may be irreversibly damaged.

Common Questions About Brain Injury in Sports

Q: What are the most dangerous sports with the most number of head injuries?

The top four sports with the most head injuries are 1) Cycling with 85,389, 2) Football: 46,948, 3) Baseball: 38,394, and 4) Basketball: 34,692.

Q: What do symptoms look like in brain injury?

Common symptoms of brain injury are confusion, loss of consciousness, vomiting, speech impairment, and headaches.

Q: What are the top three sports that result in death?

The top three most fatal sports are 1) Base Jumping, 2) Swimming, and 3) Cycling.

Q: What sport has the least number of injuries?

The top three sports with the least number of injuries are Volleyball, Softball, and Wrestling.

This article was updated on 7/23/2019

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