Exploring Brain Activation Patterns In Asymptomatic Athletes With And Without A History Of Multiple Concussions

Abstract

The long-term effects of multiple concussions in athletes are unclear. Functional magnetic resonance imaging (fMRI) studies have previously reported compensatory brain activation patterns and brain activation (i.e., engagement) differences in symptomatic athletes with a history of multiple concussions. Interestingly, these fMRI findings have been documented in absence of neurocognitive impairment. No fMRI study has examined brain activation patterns in athletes with a history of concussion who are asymptomatic (i.e., recovered from concussion). PURPOSE: To evaluate neurocognitive performance and compensatory brain activation patterns elicited by a working memory task in asymptomatic athletes with and without a history of two or more concussions. METHODS: A paired case-control design was used for study. Fourteen athletes with a history of two or more concussions were matched (age, sex) to 14 athletes with no history of concussion. All athletes were administered the Trail-Making Test Form A and B, Symbol Digit Modalities Test, and ImPACT prior to fMRI. On a separate testing occasion all athletes performed the N-back working memory during fMRI. RESULTS: Similar performance on the Trail Making Test Form A and B, Symbol Digit Modalities Test, and ImPACT were observed in both groups. The history of concussion group was less accurate than controls on the low (p =.01), moderate (p =.04), and high (p =.02) working memory conditions of the N-back task. No compensatory brain activation patterns were observed between groups, and common brain regions used to perform the task were used to the same degree during low, moderate, and high working memory demands. CONCLUSIONS: Following the resolution of symptoms, a history of two or more concussions is not associated with reduced neurocognitive performance. Functional MRI data revealed no compensatory or engagement differences during a working memory task in these athletes. However, behavioral differences on the N-back are not explained by fMRI and warrants further study.