Both the soccer players and swimmers underwent an imaging scan called high-resolution diffusion tensor imaging that provides detailed images of the brain. The researchers had neuroradiologists look at the scans, and none was found to be abnormal.
But, there were differences in the structure of the white matter in the brain. White matter is the communication network that transmits messages between neurons (gray matter) in the brain.
Study senior author Martha Shenton, a professor of psychiatry at Harvard Medical School, noted that the researchers don't know what caused the changes in the white matter of the soccer players, only that there were changes. "It could be from heading the ball, or due to impact of hitting other players or from sudden acceleration," she said.
Both study authors said they wouldn't discourage children from playing soccer at a recreational level, but that more study needs to be done to see if these changes cause any long-term damage.
Dr. Jeffrey Bazarian, an associate professor of emergency medicine at the University of Rochester Medical Center in New York, agreed that this study shouldn't cause parents to worry about their child heading a soccer ball. He said in professional players, head-to-head contact is a much more likely cause of brain injury.
"It's also important to remember that when you ask athletes whether they've had a concussion before, they may underreport injuries. If they have a concussion, it means they can't play. Plus, they don't always know if they've had a concussion," he said.
"Trying to answer this question is very important, but following athletes forward in time, rather than back, would be more likely to give us the answer," Bazarian said.
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