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Study finds loss of brain volume in MMA fighters and boxers

Volume loss found in different areas of the brain for current and retired athletes both in mixed martial arts and boxing.

UFC & Cleveland Clinic Professional Fighters Brain Health Study Media Tour Photo by Jeff Bottari/Zuffa LLC/Zuffa LLC via Getty Images

In 2011, the Cleveland Clinic announced a voluntary long-term study on the brain health of professional boxers and mixed martial artists. The idea was to evaluate the brains of fighters in the hope of discovering improved ways to prevent permanent brain injuries. Dr. Charles Bernick of the Cleveland Clinic Lou Ruvo Center for Brain Health, dubbed the study, The Professional Fighters Brain Health Study.

Bernick recently released some of his findings in the December 23, 2019 issue of “Neurology,” the medical journal of the American Academy of Neurology. The study has been renamed The Professional Athletes Brain Health Study since it was recently expanded to include professional bull riders.

The information Bernick released in December came from the study of 50 current boxers with an average age of 29 and an average of five fights; 23 retired boxers with an average age of 45 and an average of 38 fights; and 100 mixed martial arts fighters with an average age of 29 and an average of eight fights. That combat athletes were compared to 31 non-fighters with an average age of 31 who had no history of head trauma. No retired MMA fighters were included in the study because of the small number of volunteers. Men and women were included in Bernick’s research.

The Professional Athletes Brain Health Study requires active fighters to have at least one professional fight within two years of enrollment. Active fighters have to be training with the goal of fighting. The retired boxers are included in the study if they have at least 10 professional fights, have not competed in two years, and do not intend to return to competition. The control group consists of individuals who have no history of neurologic disorders, head trauma, or military service. Those in the control group also have no history of participation in a combat sport or a sport that could result in head trauma at a high school level or higher.

The first visit by participants in the study establishes a baseline which the follow-up visits can be compared to. Each exam includes a brain MRI, cognitive testing, and a head trauma exposure history. Study coordinators gather information on demographics; education medical history, previous head trauma, both related and unrelated to athletic activities, and prior involvement in other contact sports. For active athletes, the amount of sparring, concussions (if any) and head injuries within two weeks of the study, is also collected.

One surprising thing the study found was that while both the active and retired fighters displayed a loss of brain volume, the two groups showed that loss of brain volume in different areas.

What the study found was for current fighters, the loss of brain volume was in areas of the brain that suggest brain injury. As for the retired fighters, brain volume loss was discovered in areas that suggest neurodegenerative diseases such as chronic traumatic encephalopathy (CTE) or Alzheimer’s disease.

Bernick also saw that when compared to the control group, current fighters lost more brain volume. MMA fighters also had a more significant loss in brain volume than the control group, but the amount of volume loss in MMA fighters was slightly less than boxers. Boxers lost an average of 145 cubic millimeters of brain volume per year, while MMA fighters lost 100 cubic millimeters per year. The control group saw a gain of 43 cubic millimeters per year.

Bernick said of the brain volume loss, “More research is needed to determine if these small changes could help us predict what will happen for individual athletes.”

When it came to thinking and memory tests, the study did not find much of a difference between the control group and the fighters. However, when Bernick looked at the current fighters who had brain volume loss and those who did not, the study showed those with brain volume loss had worse scores on two of the thinking tests for processing speed.

While the study is a start, Bernick stressed the need for additional research.

”Ideally, future studies would build on these results and help us identify ways to predict irreversible injury so we could reduce the risks for these professional athletes before it’s too late,” Bernick said.

Bernick did note some concerns about the study. One of those concerns was that the study might not have been a truly random sample of athletes. Instead, the participants might be those who are most concerned about their health. For example, those who are showing symptoms of possible damage. Another concern was that women made up a small percentage of the athletes. The timing of the study was also a worry as the average follow-up time between baseline and last visit was 2.6 years.

Bernick received research funding from UFC, Top Rank Promotions, Haymon Boxing, Bellator/Spike TV, and UCLA Dream Fund.