Getting a blow to the head, even if it doesn’t result in a concussion, can affect your ability to learn and remember. According to this study of 80 athletes who play football and ice hockey and 79 who play non-contact sports, blows to the head can lead to brain changes and can impair memory and learning.
When the season started, those who play contact sports didn’t have concussions, and who helmets that measured acceleration following impacts. Based on brain scans, there were greater changes in white matter in the brain (plays a role in speed of nerve signalling) at the end of the season among contact sport athletes than those who played non-contact sports. There was a greater magnitude in white matter among athletes who performed more poorly than expected on tests of memory and learning. In a subgroup of both contact and non-contact athletes who did worse than expected on tests of verbal learning and memory, there were greater changes in the corpus callosum of the brain (connects the right and left sides of the brain) among than among athletes who performed closer to expectation.
These suggest a link between the number/severity of head hits, white matter changes and impairments in learning and memory, say the authors of the study. Concussions: All In Your Head.