(CLEVELAND) -- The long term consequences of combat sport are no secret, thanks to high-profile athletes like Muhammad Ali. But a new study suggests that six years of boxing can cause lasting changes in the brain, including shrinkage of areas involved in memory and cognition.
"We asked the question: Is there a certain degree of repetitive head trauma that the brain can tolerate, beyond which you run the risk of developing long term complications?" said study author Dr. Charles Bernick, associate director of the Cleveland Clinic's Lou Ruvo Center for Brain Health in Las Vegas. "And if that's the case, can we detect changes in the brain before people become symptomatic?"
Bernick and colleagues followed 109 current boxers and mixed martial art fighters, using surveys to assess their fight frequencies and MRI scans to detect changes in their brains. The more fights, the more severe the brain changes were in fighters with six or more years in the ring. And after 12 years, the number of fights was linked to poorer performance on memory tests.
"This raises the possibility of detecting brain changes before people are symptomatic," said Bernick, who is presenting the ongoing study at the American Academy of Neurology annual meeting this week in New Orleans. "If you wait for someone to start having symptoms and retire, you've bought the farm. You may not be able to do too much about it."
Mounting research in boxing, football, hockey and military service suggests smaller blows can add up to major consequences, including chronic traumatic encephalopathy, a progressive brain disease with features of Alzheimer's, Parkinson's and ALS.
"It's not just the big concussions, but the chronic accumulation of smaller blows to the head," said Dr. Daryl Rosenbaum, assistant professor of sports medicine at Wake Forest University in Winston-Salem, N.C. "We get asked all the time how many hits are too many. We don't know the answer to that question, but studies like this will help."
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