Most are aware that a concussion can result in short-term problems with cognition (i.e., memory and learning); however, a new study has found that even without a concussion, blows to the head suffered during a single season of football or ice hockey may affect the brain’s white matter and impact cognition. White matter is brain tissue that is involved in the transmission of information between brain cells. The findings were published online in the December 11 issue of Neurology, the medical journal of the American Academy of Neurology.
“We found differences in the white matter of the brain in these college contact sport athletes compared to non-contact sport varsity athletes,” noted study author Thomas W. McAllister, MD, of Indiana University School of Medicine in Indianapolis. He added, “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.”
The study group comprised 80 Division I NCAA Dartmouth College varsity football and ice hockey players, who had no history of a concussion. The participants wore helmets that recorded the acceleration-time of the head following impact. They were compared to 79 non-contact sport athletes in activities such as track, crew, and Nordic skiing. The subjects were evaluated before and shortly after the season with brain scans as well as learning and memory tests.
Dr. McAllister found that a subgroup of both types of athletes (contact and non-contact) performed worse than predicted on a test of verbal learning and memory at the end of the season. A total of 20% of the contact players and 11% of the non-contact athletes scored more than 1.5 standard deviations below the predicted score. Dr. McAllister noted that a decline this large would have been expected in less than 7% of a normal population. This subgroup showed more change in the corpus callosum region of the brain than the athletes who scored as predicted on the test. The corpus callosum is a mass of nerves that connects the right and left sides of the brain.
Dr. McAllister explained, “This group of athletes with different susceptibility to repetitive head impacts raises the question of what underlying factors might account for the changes in learning and memory, and whether those effects are long-term or short-lived.”
Take home message:
This study notes that some individuals may be more susceptible to brain trauma than others. It also reports the surprising finding that head trauma can occur among athletes who engage in non-contact sports. Only one brain to a customer, be careful with it.