Subconcussive Hits Found to Affect Memory, Learning in Some Youth-Athletes
Head impacts which don't result in a concussion may still affect some student-athletes' ability to learn and remember information, suggests a new study published online today in the journal Neurology.
For the study, 80 nonconcussed varsity football and ice hockey players at Dartmouth College were compared to 79 non-contact sport athletes. All of the study's participants underwent preseason and postseason neuroimaging, as well as learning and memory tests (the California Verbal Memory Test-II).
The study's authors sought to examine the neurological ramifications of head impacts for contact-sport athletes, even in the absence of a concussion. Five contact-sport athletes were excluded from postseason testing after sustaining a concussion during the season.
Based on the results of the athletes' preseason and postseason test batteries, the study authors discovered that certain brain regions in a subgroup of both contact- and non-contact-sport athletes were altered by repetitive head impacts within a single season.
Twenty percent of the contact athletes and 11 percent of the non-contact athletes scored more than 1.5 standard deviations below their predicted score on the verbal-memory test. Those who scored lower on the verbal-memory test were found to have greater differences within the corpus callosum region of their brains (a bundle of nerves that connects the right and lefts sides of the brain).
Given the correlation between the poorer-than-expected performance on the memory test and the corpus callosum differences, such changes "may have some functional significance," the study authors suggest.
"The degree of white matter change in the contact-sport athletes was greater in those who performed more poorly than expected on tests of memory and learning, suggesting a possible link in some athletes between how hard/often they are hit, white matter changes, and cognition, or memory and thinking abilities," said study author Dr. Thomas W. McAllister, the chair of the psychology department at the Indiana University School of Medicine, in a statement.
Overall, the study authors also found differences between contact and non-contact athletes in terms of white matter diffusion metrics in the brain. They were encouraged to find no significant neurological differences in the preseason between contact and non-contact athletes, however, which may suggest that any functional changes over the course of a given season could dissipate by the following year.
The findings of this study only bolsters previous research from McAllister, which also found that head impacts sustained while playing sports affected certain student-athletes' ability to learn and remember information.
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