Assessing the Long-Term Impact of Concussion upon Cognition: A 5-Year Prospective Investigation

Abstract

Jockeys have high rates of concussion, with 5% of jockeys receiving at least one concussion annually. The impact of acute concussion upon cognition is well understood, but less is known about the long-term effects of concussion upon cognition. Our aim was to assess the impact of concussion upon jockeys who had provided pre-concussion assessments of cognition using a prospective design. In this study, over a 5-year period, we assessed the cognitive performance of jockeys with ≥1 medically diagnosed concussion (MDC; n=17, months since concussion, M=29.18), against those who had not been concussed (NC; n=41). Jockeys who had not been concussed in the preceding 6 months completed four computer-based cognitive assessments from the CogSport battery. Unlike the majority of the small existing literature, there was no difference (p≥.05) between the MDC and NC groups after controlling for age and baseline performance. Additionally, we used a measure of reliable change to assess for clinically meaningful decrements from baseline in each test and composite score 5 years later. None of the jockeys in the MDC group recorded significant decrements on any CogSport measure from baseline (z>-1.65). The findings suggest that the presence of concussion does not result in persistent decrements in cognitive performance and that when findings are considered collectively, assessing factors beyond medically diagnosed concussion (e.g., chronic stress, undiagnosed concussion) may improve the interpretation of our current findings.