The Concussion Myth


Over the last two decades, the world has learned a lot about brain injuries. But now there are more questions than answers. There’s also a lot of confusion, fear, and unsubstantiated flimflam. 

by Michael J. Mooney   |   Illustrations by Jean-Francois Podevin

Night after night, Todd Ewen made his living when the gloves came off and the fists went up. From 1986 to 1997, he was an enforcer in the NHL. He was never a star, but his nickname, “The Animal,” was a testament to his ferocity on the ice. Early in his career, he shocked the league when he came to blows with Bob Probert — the Detroit Red Wings enforcer widely regarded as hockey’s heavyweight champ — and dropped the veteran with just one punch. 

Ewen played with the St. Louis Blues, San Jose Sharks, Mighty Ducks of Anaheim, and Montreal Canadiens — where he won the Stanley Cup in 1993. He retired after a knee injury in 1997, ending his career with 36 goals and 1,911 penalty minutes over the course of 518 regular season games. 

After Ewen’s hockey career ended, he ran a successful real estate business with his wife and eventually served as head coach for the Saint Louis University hockey team. By all accounts, he enjoyed good relationships with his wife, his children, and his grandson, and he had a supportive network of friends. 

But he also had his demons. He knew that he’d taken a lot of hits to the head during his time on the ice and as he heard story after story about chronic traumatic encephalopathy, the crippling brain disease better known as CTE, Ewen worried more and more about the long-term effects of all his concussions. He saw reports that fearsome ex-hockey players like Derek Boogaard and Bob Probert — the enforcer he’d gained notoriety for fighting — had been posthumously diagnosed with CTE. 

Ewen suspected he might have it, too. It wasn’t just that he’d been hit so often when he played. He was also struggling with memory loss and depression, two symptoms often linked to brain injury. 

He decided he didn’t want to face a future of the dementia associated with CTE, and he refused to be a burden to his family. So, on Sept. 19, 2015, Ewen went down to the basement of his Missouri home and shot himself in the head. He was 49 years old. Soon after, a Toronto neuropathologist convinced Ewen’s family to donate his brain for study. The family agreed — and the results of the tests surprised them. Ewen may have suffered from depression, but he didn’t have CTE. 

These are the kinds of stories that bother Dr. Munro Cullum more than anything else. 

Cullum has dedicated his career to unlocking the secrets of the human brain, with a specific focus on concussions, brain trauma, and dementia.

As a clinical neuropsychologist specializing in the assessment of cognitive disorders, Cullum has dedicated his career to unlocking the secrets of the human brain, with a specific focus on concussions, brain trauma, and dementia. He serves as Chief of the Division of Psychology and Director of the Neuropsychology Program at the University of Texas Southwestern Medical Center. He’s also the Pam Blumenthal Distinguished Professor in Clinical Psychology and Clinical Core Leader of UT Southwestern’s Alzheimer’s Disease Center. For more than 20 years he’s worked closely with the Dallas Cowboys and Dallas Stars, too, performing neuropsychological evaluations and monitoring both current and retired players — including some of the biggest names in sports. 

Cullum is tall and lean, with glasses and a calm demeanor. In his office at UT Southwestern Medical Center, though, beneath shelves lined with various brain and skull models, he gets a little agitated as he talks about Ewen’s story. 

“You shouldn’t be telling somebody that they have CTE, because we don’t have diagnostic criteria for it during life,” he says. “There are some very serious ramifications.” 

As the subject of concussions — and the issue of CTE, in particular — has garnered more headlines over the years, Cullum has written papers and op-eds, and he’s done plenty of interviews about what studies have taught us and about what he’s learned from his experiences. Now, though, as he’s sitting behind his desk, he wants to talk about what we don’t know about brain injuries.

Concussion Fiction:


Data shows loss of consciousness actually occurs in less than 10 percent of concussions. “Concussion symptoms” are fairly nonspecific. Some common symptoms include temporary dizziness, light sensitivity, noise sensitivity, nausea or vomiting, fogginess in thinking, difficulty with attention and concentration, disorientation, balance problems, sleep disturbance, and irritability. That’s a lot of potential indicators, and not a single one of them, or even a certain combination of them, is 100 percent indicative of head trauma. Depression can be a symptom of a concussion or CTE, but as in the case of Todd Ewen, it may just mean the person needs treatment for depression.

There’s no pill you can pop to prevent a concussion.

There’s no strap or band you can put inside a helmet that tests whether someone sustained a brain injury. There are sensors that can tell you the estimated g-force incurred during an impact — how hard someone was hit — but that doesn’t identify concussions, no matter what product advertising might claim. There’s also no blood test. There are tests that can tell whether you have bleeding in your brain, but most concussions don’t involve bleeding at all. And there are no vitamins you can take that will, with any degree of scientific certainty, help prevent concussions. There’s no good data to support any of those things, Cullum says. 

Of course, with the number of high-profile deaths and the exponential increase in the amount of media coverage given to the intersection of sports, concussions, and CTE in the last decade, it’s not difficult to see why so many people are looking for ways to reduce their risks. In 2015, a Boston University study reported finding CTE in the brains of 87 of the 91 deceased former NFL players examined. And CTE is terrifying. It’s associated with impaired thinking, memory, and judgment, and sometimes with dementia. Compounding the worry is the fact that, while we think concussions may lead to CTE in some cases, we don’t know how many concussions it takes, or why CTE develops in some people and not others. These open questions, and a lack of public knowledge, naturally create opportunities for businesses looking to capitalize. That’s how products like concussion-prevention vitamins wind up on the market.

Cullum’s interest in brain function was piqued during high school. He relished his classes in biology, psychology, and anatomy, marveling at both how little we understand about the human mind and how much we’ve learned. 
The brain was like outer space, he thought, except inside the human body. And learning more about it would mean plenty of opportunities to shed light on little-understood diseases and help improve people’s quality of life.

His attempts to alleviate some public fears begin with slashing through the known myths that surround what a concussion is and the best ways to go about treating one. Cullum defines a concussion as a temporary disruption in normal neurologic function as the result of trauma to the brain. That can come from a hard blow to the head — but not every hit to the head is a concussion. You can also get a concussion from a hit to the body, if your head is jostled enough. The human skull is, as Cullum and his colleagues say, “an imperfect box.”

Concussions seem to involve some element of rotational force too. To explain, Cullum picks up a painted plastic brain model from the shelf above his desk, twists it apart, and points to the light-colored, fibrous-looking material inside.

“The white matter is what connects all the different parts of the brain with all the other parts,” he says. He twists the plastic brain ever so slightly in his hands to demonstrate the trauma. “That can cause a stretching of these connective fibers, more so than just a flat, straight, linear hit to the head. So, in a case of a concussion with a twisting motion, you’re getting the whole cortex twisting.”

One of the symptoms most often associated with brain trauma is a headache, but that’s tricky. A lot of things cause headaches, including surface-level bruises on the scalp that aren’t concussions. On any given day, the base rate of headaches in a normal college population is about 20 percent.

“So, if you come in to see me after a hit to your head, or on just a random day, you have a good chance of having a headache,” Cullum says. There are a lot of other factors that confuse the issue — including misconceptions about how to recognize and treat concussions and what a concussion actually looks like.

Concussion Fiction:


Concussion or not, Cullum says this is a fast way to induce irritability — which could then be mistaken for a concussion symptom or exacerbate symptoms.

A few years ago, Cullum was performing a screening exam on a high-profile Dallas athlete — he won’t say whom. 

The exam involved tests that gauged reaction times and simple memory exercises designed to give Cullum a baseline of symptoms and cognitive abilities for comparisons should the athlete sustain a head injury in the future. This is standard procedure now, but it was relatively new at the time. On this particular day, the athlete was performing poorly, “like a patient with dementia,” Cullum says.

“I don’t think you’re trying your best here,” Cullum told him.

The athlete grinned. “I’m doing the best I can, doc.”

Cullum says it wasn’t rare for players to “sandbag” these tests when standard baseline testing started. Some players tried to score low on their baselines so it might be easier to conceal a concussion down the road. Every athlete in every sport knows that, no matter how far along or accomplished a career may be, there’s always someone else waiting in line to fill an empty roster spot. And until recently, a concussion — what announcers used to call being “shaken up on the play” — didn’t seem serious enough to miss playing time over.

Today, amid the increase in concussion coverage, athletes seem to take it more seriously, Cullum says. They understand that it’s for their safety. 

“Almost all professional sports now have some sort of concussion protocol, and many of them do include a baseline neuropsychological preseason assessment,” Cullum says.

All teams in the NHL and NFL have neuropsychologists who test players every two to three years, usually to update their baselines. Screening is often conducted using an exam called the SCAT5, which involves a symptom assessment where doctors flag potentially problematic feelings that players may be experiencing. The next level is the neuropsychological and neurocognitive screening, which assesses skills like concentration, immediate memory, and balance. Many teams use computer-based programs to perform these tests, in conjunction with trainers and physicians who know the players well and watch for mood swings or changes in their behavior, making it much easier today to keep a good handle on who may be suffering from potential concussion symptoms.

“You shouldn’t be telling somebody that they have CTE, because we don’t have diagnostic criteria for it during life. There are some very serious ramifications.”

Munro Cullum

Concussions are often associated with sports and military combat, but anyone can get hit in the head. 

Still, they’re rare enough that Cullum dismisses the idea of buying preventive supplements — even if they worked. Studies also show that most concussions don’t result in any terrible long-term effects, and that the majority of people recover from them quite well. Concussions have occurred all throughout history, we just know a little more about them now.

When performing tests on the general population, or people who aren’t athletes and who probably don’t have baseline scores, neuropsychologists like Cullum compare patients with data accumulated from others of similar ages, education, backgrounds, and genders.

Comprehensive, standard brain tests administered by neuropsychologists often take several hours. They’re designed to address attention, concentration, reasoning, language, memory, reaction time, and thinking speed. One test involves connecting numbers and circles on a page as fast as possible. Other tests might involve hearing, remembering, and repeating strings of numbers or words.

“Neuropsychology is kind of like Sherlock Holmes piecing together someone’s brain,” Cullum says. “What we get after a thorough evaluation is a cognitive profile. Where are your strengths? Where are your weaknesses? And do these match up with the way that we know the brain works — or do they match up with what disorder or dysfunction we suspect or are concerned about?”

Fortunately, because these kinds of tests have been done on thousands of people, neuropsychologists have good normative reference values with which to compare people who might not have a personal baseline. Barring any unknown ailments — say, someone who performs poorly on a concentration-related test because they have attention deficit hyperactivity disorder — doctors can use data to help figure out the parameters that your scores should fall into. Which is how Cullum knew that famous athlete was sandbagging.

He recalls another time when another star player had suffered an injury and was completing a brain test using a computer. Cullum was monitoring him, but at some point, the player stopped responding. At first it looked like a giant red flag: a possible problem with attention or concentration. Cullum decided to check on it.

“Was I supposed to be doing something?” the player asked, leaning back in his chair.

It turns out that he wasn’t having a problem with paying attention — he just hadn’t bothered to read the instructions.

Concussion Fiction


“What are you going to have if you lock your 15-year-old away in their room without contact with friends, TV, or their phone for a week?” Cullum says. “Lots of irritability. Maybe some depressive symptoms. Maybe headaches, because it’s a change in their routine. All potential symptoms of concussions.” In other words, the methods used to alleviate symptoms could actually be making these symptoms worse.

There’s a University of North Carolina study that examines the concussive symptoms of people who have suffered hits. 

There were cases where a person was hit with a 60 g-force and showed concussive symptoms. There were other cases where a different person was hit with a 100 g-force and had no symptoms. This can make it difficult to know how worried to be about concussions.

“We actually don’t know what the risk factors are for concussion symptoms,” Cullum says. “We’ve done some retired NFL player studies, and we’ve talked to some of these guys who, after 20 years of play, swear they’ve never had a concussion. Some of them say they’ve had too many to count. There’s no one unifying variable to diagnose concussion.”

Part of the problem: No two concussions are alike. This is largely because no two brains are alike, and a potential concussive blow has countless variables. There are also innumerable factors that might determine how an individual reacts to a concussion, including neck musculature, predispositions in the brain’s white matter, and genetic makeup.

Recovery times can vary drastically, too. Most people recover from concussions within a few days. There’s a small subgroup, though, Cullum says, that takes longer to recuperate, and he pinpoints and flags people who might be at risk for this long-term predisposition. Right now researchers are looking at a diverse group of factors that could include your natural ability to recover from injuries and your psychological makeup. Attitude and personality may even play a role.

CTE is even more difficult to pinpoint. Dr. Cullum says the disease is considered “quite rare” — in part because, even with the pathological diagnosis, there’s not 100 percent agreement in the field on who has it and who doesn’t. Statistically speaking, human beings are also remarkably poor when it comes to risk assessment, and all the dramatic stories of these strong, strapping former athletes killing themselves or slowly withering away certainly doesn’t help on that front.

Part of the problem: No two concussions are alike. This is largely because no two brains are alike, and a potential concussive blow has countless variables.

“There’s a lot of hysteria about it,” Cullum says. “The public just eats up stories. The suicides have actually been quite rare — rarer in retired NFL players than in the general population. Likewise, NFL players don’t die earlier. They tend to be healthier on average, actually.”

Complicating it all is the fact that CTE can’t be diagnosed on a living brain. Like other neurodegenerative diseases, CTE involves the misfolding of a protein called tau. As the proteins misfold, they clump together, spreading throughout the brain and killing brain cells. These misfolds are found in a specific pattern deep within the brain — in other words, they’re hard to identify. Though tau can now be imaged in a living brain, this imaging is nonspecific — it might be present in the brain of someone with a neurodegenerative disorder, but healthy older people might have it too. So, at least for now, you can’t know one way or another if you have CTE while you’re still alive.

That also makes it hard to test and interview patients and catalog their symptoms. Since diagnoses are made posthumously, interviews conducted with family members in an attempt to pinpoint characteristics might be skewed or incorrect. They might describe symptoms like irritability, memory loss, or headaches — again, nothing that’s specific only to concussions or CTE.

Think about the Boston University study that confirmed CTE in almost all the donated brains of former NFL players. At face value, these numbers sound staggering — as though CTE is everywhere, and anyone who plays football is at high risk for it. But Cullum points out that these studies recruit people who had behavioral problems or depression while alive. Family members who sent in their deceased loved ones’ brains were already worried. There’s no control group for comparison, because these studies aren’t calling for the brains of random healthy former NFL players.

All that said, we do know that CTE may be related to repetitive concussions, and there’s cause for worry there. But there are still a lot of questions left to ask.

“How many is too many?” Cullum says. “I’ve seen patients who have had 10 concussions or more. Clinically, if their recovery is taking longer and longer for each one, that’s a sign it may be time to do something else and reduce their risk. But at what point do you say enough is enough? It is a challenging question and one that requires careful consideration of each individual case.”

Cullum is often approached by worried parents who wonder if they should pull their kids out of sports — or never let them play in the first place. Often this question is followed up with: “Would you let your own kids play sports?”

Is it safe to play?

Cullum suggests that parents who wonder whether their kids should play football or other high-impact sports should ask these questions first:

  • Are they good candidates for the game?
  • Are they physically able to play?
  • Are they psychologically ready?
  • Can they learn the proper hitting and tackling techniques that will keep them and others safe?
  • Do the parents feel comfortable with the environment in which their children will be training? With the team? With the coaches? Is there an athletic trainer involved?
  • What are the injury protocols?
  • What’s the return-to-play policy?
  • Does the team take concussions seriously?

Concussion Fiction:


Not every hit to the head is a concussion. You can also get a concussion from a hit to the chest, or without being struck at all, if your head is jostled enough.

Cullum tells a story about a mother who had two daughters, both of them high school soccer players. 

The girls had each suffered a concussion or two, but the mother didn’t worry much till one of her daughters got a third. That seemed like too many to her. The mother wasn’t sure, but she thought maybe three concussions crossed some kind of line.

“Should we stop this?” she wondered.

To her mother’s great relief, the daughter decided herself that she’d had enough of soccer and opted to join her high school debate club instead. One day the girl was on a break at a national competition when, without warning, a boy from one of the other teams came racing into the room. He was flailing his arms, as teenage boys are sometimes wont to do, and by chance, his elbow connected with the girl’s temple.

“She was out cold,” Cullum says. “Her worst concussion ever — at a debate tournament.”

Being the sort of expert he is, Cullum is often approached by worried parents who wonder if they should pull their kids out of sports — or never let them play in the first place. Often this question is followed up with: “Would you let your own kids play sports?”

He did. Both of Cullum’s kids participated in extracurricular athletics. Photo evidence lines the wall behind his desk. His daughter participated in ballet, and though she didn’t suffer any concussions while dancing, her brother played both football and soccer and, yes, had his fair share of hits and concussions in those sports. When Cullum hears concerned parents say that they’d never let their kids play certain sports, he points out that, according to the Centers for Disease Control and Prevention, the No. 1 concussion risk for people under the age of 20 is falling off a bicycle. He asks those parents if they ever plan to let their kids ride bikes.

“Where do you reel this in?” he asks. “What are the risks versus benefits? We all need to do the things we enjoy. Being active and being out there is, I think, more important. It’s certainly worth some of the risks. Being a couch potato and sedentary has its own serious health risks.”

He still thinks that the game of football needs to make improvements. In the early 20th century, football was a rough-and-tumble sport known for its hard hits, injuries, and occasional deaths: Between 1900 and 1905, at least 45 people died from playing. In 1905, President Theodore Roosevelt held a meeting that brought coaches and athletic personnel together to devise strategies for making football slightly less brutal — and fatal.

These were the first measures taken to make the sport safer, though the NFL didn’t even require helmets until 1943. And while helmets do much to reduce player death, they don’t prevent concussions. In fact, a helmet can enhance a player’s feelings of invincibility. And when a linebacker or a fullback feels invincible, that probably means more concussions, not fewer.

“There’s data indicating that we can make safer helmets,” Cullum says. “We definitely can, to some extent, but you’re never going to have a concussion-proof helmet.”

Instead, football teams and leagues need to teach proper tackling techniques and increase penalties for dangerous plays. Fortunately, all 50 states have a return-to-play policy that removes kids suspected of having concussions from the field for a period of time. A Texas law passed in 2011 dictates that players with head injuries be removed from play for at least a week and need clearance from a doctor.

“That’s a step in the right direction,” Cullum says.

Despite his field of study and the work he’s done surrounding concussions, Cullum is an avid sports watcher — though he admits he’s never excited to see a brutally hard hit, and he gets worried when hockey players fight. He cringes when he sees an NFL player get an especially hard hit or show signs of concussion.

“I watch sports with a little bit of a different eye,” Cullum says. “But I still enjoy it.”

According to the Centers for Disease Control and Prevention, the No. 1 concussion risk for people under the age of 20 is falling off a bicycle.

Cullum says data does not support the truth of any of these supposed “cures” on the market:

  • Pills and vitamins that prevent concussion.
  • Helmet sensors that detect brain injury.
  • Blood tests for concussion.

One of the biggest steps forward in the study of the brain ...

came at UT Southwestern in 2015, with the establishment of the Peter O’Donnell Jr. Brain Institute — a major investment in the unexplored frontier of the human brain. 

Now, with the largest team of researchers and physicians in North Texas focused on the neurosciences, the O’Donnell Brain Institute brings together different medical disciplines to understand how the brain operates, to discover cures for previously incurable or little-understood ailments, and to apply its findings to the treatment of neurological disorders and injuries.

At the moment, Cullum is also excited about the Concussion Texas (ConTex) studies, which include a North Texas concussion registry (ConTex1) and a collaboration between UT Southwestern and the University Interscholastic League, the governing body overseeing competitions in Texas public schools. This study (ConTex2) ultimately seeks to compile one of the biggest, most comprehensive statewide concussion databases ever created.

“We have research coordinators in each of these concussion clinics, basically doing detailed interviews, questionnaires, checklists, and mood, family, and concussion histories with individuals ages 5 on up,” Cullum explains. “Most of it’s high school age, and we are doing a deep dive into the nature of their symptoms at the time.”

Since Texas has more student-athletes than any other state, this kind of research is invaluable. The study will encompass male and female athletes — important because not much is known about women’s concussion symptoms, other than the fact that women tend to be more prone to concussions in general. So far, about a fourth of Texas schools have agreed to contribute via having their trainers or nurses enter data and information about concussions suffered.

These studies, Cullum says, will go a long way toward a better understanding of the frequency and recovery of concussions. As of now, even the CDC doesn’t have specific numbers on how many concussions occur in the United States. 

“They’ve encouraged scientists to develop a nationwide surveillance system,” Cullum says. “So we’re hoping that our North Texas and statewide registries might serve as a blueprint for that.”

The field of neuropsychology has changed a lot over the last quarter-century, and it changes more every year. In time, Cullum hopes to help further demystify the human brain and dispel some of the myths surrounding concussions — especially those propagated by the sensationalized headlines that create unnecessary fear in the patients he sees. 

“I figured this would be a career’s worth of study,” Cullum says. “And it still is. There’s just so much we don’t know. The brain is truly one of the final frontiers.”

Dr. Munro Cullum Portrait by Elizabeth Lavin.