You know nothing about brain injuries in MMA. Then again, you probably know everything.

That, in a nutshell, is the state of play for the UFC and every mixed martial arts promotion, fighter, researcher and fan. New findings carry ominous—if not entirely surprising—warnings. But at the same time, brain injury science in MMA lags behind that of other sports, even as MMA gains new followers by the day.

As a result, the MMA community finds itself in a race against time to bring medical evidence up to speed with what are essentially common-sense assumptions about the inherent dangers of the sport, before a tragedy occurs.

“I would say there is a sense of urgency,” said neurologist Dr. Charles Bernick, associate medical director at the Lou Ruvo Center for Brain Health in Las Vegas and one of the nation’s leading experts on brain injury and disease. “We’re making progress in our research, but we don’t know enough to make firm recommendations. There are a lot of questions we just don’t know the answers to.”

In the meantime, there are few commonly accepted methods of evaluating the extent or risk of brain injury in an MMA fighter. Bernick is hoping his research will help to change that.

“There really is no objective way to decide when a person should stop fighting or not be licensed to fight,” Bernick said. “When do you decide not to fight or grant a license? It all depends. We have no objective way to make these decisions.”

There are a few objective truths out there, however. MMA is violent, and its participants do take risks by participating. MMA is relatively new, with UFC 1, for example, having taken place in 1993. And MMA is growing, as evidenced by a lucrative contract with the FOX network and a steadily rising number of promotions and events.

ESPN reported in December that 3.2 million children under age 13 take MMA classes.

Despite the ballooning interest, recent research and tragedies in other sports are casting a pall over the long-term health of MMA athletes, and perhaps even the sport itself.

Earlier this spring, Bernick and his team revealed findings that showed substantial degradation in certain areas of the brains of long-tenured MMA fighters. The affected areas are critical to learning, memory and emotion. Evidently, these degradations are consistent with the symptoms of chronic traumatic encephalopathy (CTE), a condition caused by multiple head injuries and characterized by dementia, memory loss, aggression, confusion and depression. CTE generally appears years, or even decades, after the trauma occurs.

The race to learn more about fighter brain injuries took on new urgency following high-profile deaths among former NFL players, and the class-action lawsuit more than 4,200 retired players are bringing against the league that claims the NFL concealed or downplayed the risks of concussions and other head trauma.

Just over a year ago, former NFL All-Pro linebacker Junior Seau committed suicide, and his family's lawsuit claiming his death resulted from brain injuries suffered during his playing career is now part of the larger class-action suit against the league. Autopsies of Seau as well as former players Dave Duerson and Ray Easterling—who also committed suicide—showed they suffered from CTE, which can only be definitively diagnosed after death.

The legal ramifications for the NFL are still unfolding. The human consequences are much clearer. Sports attorneys say both could hold lessons for MMA.

“MMA could learn from the litigation of the NFL,” said Matthew Mitten, director of the National Sports Law Institute at Marquette University Law School. “Don’t wait until former athletes suffer strong adverse effects. Be proactive rather than reactive. You can’t totally eliminate the risk, but at some point you could see potentially changing down the road.”

“Hazy Glass”

Nick Denis didn’t wait for an outside body, or his own body, to make the decision for him.

At 29 years old, Denis was 11-3 as a professional cage fighter and 1-1 in the UFC, by far MMA’s most prominent promotion. Though his UFC career was not even a year old, he had already gained popularity with fans in part for a hard-hitting style unusual for the bantamweight division, where fighters compete at 135 pounds.

In his debut in the UFC Octagon in January 2012, Denis needed only 22 seconds to score a knockout victory. But it was Denis’ first professional loss, sustained three years earlier, that ultimately proved the bigger turning point. In 2009, heavy-fisted Marlon Sandro took 19 seconds to shut off Denis’ lights.

“My retirement kind of started when I suffered that first knockout. It was pretty bad,” Denis said. “It felt like I was covered in hazy glass or cobwebs. Over 30 or 60 minutes, the cobwebs pulled away. They were saying I wouldn’t be able to watch TV or read for months, and I wouldn’t have any appetite for a while. Luckily for me, none of that happened.”

He had avoided major repercussions, but the episode still got Denis thinking. And in November, he surprised plenty of observers when he retired from MMA.

Denis was promising, but he also was no ordinary fighter. Before turning pro, he was a doctoral student in biochemistry. Following his loss to Sandro, Denis began looking through medical journals, and it was there he discovered a new term: subconcussive trauma.

The new term is also something of a new concept and final frontier for brain injury science. Subconcussions are smaller than full-blown concussions, but over time can still cause serious harm, including CTE, in the brain.

“I had access to databases and libraries. I had never heard of subconcussive trauma before,” Denis said. “Football and hockey players, you look at their brain scans and they’re 40 years old and their brains look like deformed sponges, easy to compare with people who had dementia or Alzheimer’s disease. I was like, ‘this is crazy.’ You come to the realization that people think a concussion is where the damage occurs, but there’s damage all along the board.”

“A Discriminatory Feel”

Part of the problem is that the science is still incomplete. In an MMA context, Keith Kizer, executive director of the influential Nevada State Athletic Commission, said medical research on MMA has long been lacking, in part because doctors have typically spurned the sport.

“Questions are finally being asked,” Kizer said. “When I came on seven years ago, where was the medical community? You had great ringside doctors and so on, but a lot of the doctors were against these sports. It was almost a discriminatory feel from the medical community.”

Fortunately, this perception is changing. Bernick’s recent findings were part of the Professional Fighters Brain Health Study, which is aimed at understanding the cumulative effects of head trauma on the brains of combat athletes.

The study, slated to take place over several years, just completed its first year. To date, 135 MMA fighters as well as 104 boxers are participating, though Bernick hopes to recruit up 400 pro fighters for the research.

Promotions and athletic commissions have not historically rushed to embrace research or help address brain injuries, though there are some signs that also may be changing.

In 2011, UFC parent company Zuffa announced that the UFC’s 350 athletes would be fully covered for accidental injuries suffered in training and non-training incidents. The UFC already covered injuries sustained during competition. Other promotions, however, offer far less.

Kizer said the Nevada commission is working with the Ruvo Center by sharing more information. Bernick noted that UFC leaders are making more appearances (and donations) at brain injury fundraising events.

But the journey is still in its early stages. New findings like those on subconcussive trauma indicate that brain injuries can occur and accumulate away from the bright lights and highlight reels. That means the training gym.

Before retiring, Denis trained at Montreal’s prestigious Tristar Gym, home of UFC welterweight champion Georges St-Pierre and a veritable breeding ground for elite fighters. To hear Denis tell it, brain injury culture in the gym is akin to a don’t-ask-don’t-tell environment.

“A good analogy is eating junk food. Everyone knows it’s bad for you, but you joke about it and you keep doing it,” Denis said. “Everyone knows it’s harmful, but no one knows to what degree. Fighters don’t do a lot of research because they don’t want to know what they’re going to find.”

Denis said most gyms take precautions, but that they may not be enough.

“At Tristar, they said things like ‘don’t kill each other, we’re all friends here.’ They tell you to take time off if you need it and they tell you to protect yourself. But it’s not like they’re reading statistics or journals, either,” Denis said. “If it ever came up in the gym, it was like, ‘don’t worry about it, you’re going to be fine,’ and that was it. It’s too painful to even talk about.”

Though the cost of training injuries are covered for UFC fighters, MMA training is not directly regulated or monitored by athletic commissions or any other entity. Kizer said individual fighters and camps should take more responsibility for their own brain health and those of their charges.

“At the end of the day, a lot of this takes place beyond our scope, in the gym and the sauna,” Kizer said. “Once you know enough about the right way to do things, you do it in your entire career arc as well as just on fight night, when there are doctors present and you can get testing. Education is the important thing. You’re a real athlete, so act like it. Take it seriously.”

Even if training exists beyond their scope, athletic commissions still wield enormous influence. Commissions are responsible for, among other things, training and licensing referees, evaluating fighters and permitting them to fight and levying appropriate medical suspensions in case of injury. As it stands, however, state athletic commissions operate more or less independently from one another, with rules and standards varying widely.

The Nevada State Athletic Commission, generally considered a leader in its field, requires fighters to submit a brain MRI without contrast and an MRA scan of cerebral circulation unless specifically directed otherwise. The tests are eligible to satisfy this requirement if they were conducted within the past five years, and the requirements are the same for young fighters as they are for those age 36 and older or those who have more than 425 rounds of professional experience.

Denis suggested that athletic commissions consider monitoring training environments more closely.

“In training week to week, that’s where it happens,” Denis said. “It wouldn’t be the worst idea for gyms to have a license or insurance measures to make them liable. After a fight, sometimes the medical suspensions order fighters not to spar or train. But there’s no way to make sure that doesn’t happen. Across the commissions in North America, they should all have the same rules. They should communicate with each other 100 percent.”

Kizer said commissions “often share past medical records on a case-by-case basis.” He acknowledged that “it would be better if there was a national medical registry,” but noted that concerns over cost and privacy make that a “difficult” proposition.

Commissions are always looking for ways to improve standards, according to Kizer, who added that the equations around licensing are more complicated than they might seem. Factors as ostensibly unrelated as fighter pay, Kizer said, can play a role.

“If we beef up our standards, fighters make such little money they might lose money on getting the tests,” Kizer said, noting brain tests can cost up to $2,000. “If [a new test or standard] needs to be added, it’s going to be added. But being more safe is not always the best decision and it doesn’t happen in a vacuum.”

Inexact Science

This sort of multivariant, case-by-case approach is standard operating procedure for MMA when it comes to brain health.

“It’s always subjective as far as what you require of a fighter after a fight,” Kizer said. “With a severe knockout, it’s easy to make the call. You go to the hospital, get a CAT scan and set the suspension. But what if they’re not knocked out? It’s a tough thing.”

That’s where the current research race comes in. Bernick and his team—the nation’s only research team regularly studying brain injuries in combat athletes—are hoping their work ultimately leads to a more structured, science-driven approach to assessing brain health and protecting fighters.

Ideally, Bernick said, research would lead to “some kind of risk factor index that can be useful to fighters and regulatory agencies.”

For example, the MMA community could one day develop an algorithm that accounts for things like genetics and number of fights and knockouts, then generates a risk factor “score” for each fighter.

In the meantime, some interesting tools are already in the field. An iPad app that tests reaction times is in use in some areas. A special mouthpiece can measure the force of head blows.

But the ultimate objective of many experts is benchmarking. The NHL and other groups use a tool called the ImPACT test to assess brain function in players who may have sustained a concussion. The test data is compared against a baseline to help determine whether a player can return to action.

Denis said MMA could employ a similar approach.

“To get a license to fight, there should be a baseline of cognitive function, a memory test and mental capabilities,” Denis said. “You develop a baseline and a way to assess the deviations from that baseline.”

The Case Against MMA?

With medical science playing catch up, what are the short- and long-term risks to MMA? Could a similar legal cloud to the one shadowing the NFL be hanging over the head of the UFC?

“There are inherent risks in MMA," Marquette's Mitten said. "The real question will be whether anything the UFC or any other group did or did not do enhanced those risks."

One of the principal allegations in the NFL players’ lawsuit is that the league knowingly obscured brain injury science and misled players and the public, all in the name of financial gain.

In the context of MMA violence, however, the sport may have a key legal ally: violence itself.

“The sport is so incredibly violent that it would be hard to argue [fighters] were not aware they were assuming risks. How could anybody make the case that they were misled?” said Michael Gilleran, a sports attorney and the executive director of the Santa Clara University Institute for Sports Law and Ethics. “There’s no attempt to minimize or conceal that violence.”

Kizer said comparing MMA to the NFL was an apples-to-oranges proposition.

“In the NFL, you’re taken out for a few plays and then you go back in,” Kizer said. “In MMA, that would never happen. The referee stops the fight and there’s a medical suspension.”

Other sport comparisons might hold more water—and more legal risk for promotions like the UFC. According to Mitten, statements that MMA is less dangerous than football, boxing or other sports might be legally thorny. UFC President Dana White has previously said MMA is safer than the NFL and boxing.

“You want to be careful about that,” Mitten said of the comparisons. “You don’t want to minimize the risk and say it’s better than boxing.”

Mitten said these comparisons could potentially be construed as attempts to downplay the injury risks. This may be especially true now that research is showing that MMA may not necessarily be safer than its sister sport.

“It does seem like boxers have greater reductions [in brain capacity],” Bernick said. “But MMA is not immune to these injuries. The more exposure you have to fighting, the more disruption you see in the brain…I don’t know if we have enough knowledge to say one is safer than others. An MMA fighter who fights frequently might just be at greater risk than a careful boxer.”

The UFC did not respond to messages seeking comment for this story.

Though it seems fighters knowingly assume the risk of brain injury in selecting their line of work, and that legal risk to promotions like the UFC is fairly low as a result, sports attorneys pointed to groups like athletic commissions as being more directly accountable for fighter health and well-being, particularly in terms of licensing and referee protocol.

“It’s a question of whether somebody is competent to make a decision,” said Ronald Katz, chairman of the board of Santa Clara’s sports law institute and an attorney who won a $26 million jury verdict in a 2008 class-action lawsuit of 2,062 retired NFL players against their union. “The referee makes that determination, so the sport has some responsibilities there. It’s the responsibility of the boxing commissions to say whether to grant permits. Each commission has its own legal framework.”

Kizer defended MMA referees, calling it a complex job and pointing to fighter health outside the cage as the most promising area for improvement.

“It’s not just punches that referees look at,” Kizer said. “It’s eyes and breathing. Sometimes you can hear the air come out of them. Those refs have a better angle than anyone. They compare later rounds to earlier rounds. It’s really more pre-fight and post-fight issues that can be tweaked, rather than during a fight.”

According to Katz, a medical calamity, not a legal one, is more likely to spur changes in MMA’s brain injury culture. Though no UFC fighter has died or suffered a major head injury in the promotion’s history, the lesson from the new research and the NFL suit is that the danger stretches well beyond the cage.

“It’s predictable that something bad will happen,” Katz said. “There may very well be some sort of tragedy that occurs that causes people to reexamine this. I hope it doesn’t happen, but it’s hard to think it wouldn’t.”

For his part, Denis hasn’t watched MMA since retiring. He keeps busy by blogging and traveling with his girlfriend. But he expressed concern for his former colleagues. The newness of the sport, the current shortage of actionable science and the delayed onset of conditions like CTE could be creating a perfect storm for MMA's athletes.

“The first generation of fighters just retired,” Denis said. “Unfortunately you’ll probably see some of our big MMA heroes be more and more not right. You’ll see people getting worried. You don’t wish that on anyone, but I think it’s coming.”

Scott Harris is a freelance writer and a featured columnist for Bleacher Report. All quotes obtained first hand unless otherwise noted. Follow Scott on Twitter.