(RxWiki News) Serious blows to the head that affect the brain's ability to work are among the risks of contact sports. And concussions aren't the only injuries that can affect brain function.
A recent study suggested that college football and ice hockey players' brain function declined during a single sports season, even when their head injuries did not result in a concussion.
"Protect your head while playing contact sports."
Thomas McAllister, MD, of Indiana University School of Medicine, was this study's main author.
He and his team of investigators completed their research while Dr. McAllister was at Geisel School of Medicine at Dartmouth University. Varsity athletes on that New Hampshire campus were subjects of this study.
From 2007 through 2011, these researchers tracked brain function in 80 football and ice hockey players who had not been previously diagnosed with a concussion. Immediate symptoms of concussion include confusion, memory lapses, lack of physical balance and coordination and slower reflexes.
All 80 players wore helmets that recorded how fast their heads were moving upon impact with another player or object during games. Also, for comparison, 79 players from such non-contact sports as track, skiing and rowing were included in the study.
Except for five contact sport players, the athletes underwent post-season brain scans and tests of their verbal and memory skills. The five excluded players had sustained concussions during their playing seasons.
These researchers found that a fraction of players in both groups did not perform as well as expected on the post-season tests. But more of the players in contact sports had lower scores: 20 percent scored less than the researchers predicted they would. Among players in non-contact sports, 11 percent scored lower than was expected of them.
By further comparison, brain scans showed that contact sport athletes who performed worse on the tests also showed more change in the "white matter" brain tissue that helps determine how fast nerve signals are processed. Those nerve signals help the brain control thinking and other bodily functions.
That changing white matter suggests “a possible link … between how hard [or] often they are hit, white matter changes and … memory and thinking abilities,” the researchers wrote.
These researchers also wrote that more study is needed to determine how long-lasting the reduced memory and thinking skills might be in athletes who are not diagnosed with concussions. Concussions can occur whether or not a person temporarily loses consciousness. In addition to being hit on the head, being violently shaken also can lead to concussion.
This study was published online December 11 in Neurology.
The National Institutes of Health and the National Operating Committee on Standards for Athletic Equipment funded the study. Three of the 11 researchers disclosed that they were investors in technological instruments used to collect study data.