Prevalence of Post-Exertion Cognitive Test Failure in Varsity Athletes with a History of Concussion

Abstract

Abstract Purpose The purpose of this study was to determine whether varsity athletes with a history of concussions (6+ months from injury) show post-exertion cognitive alterations relative to their control counterparts. Methods Sixty-eight participants (34 with a HOC; 34 carefully-matched teammate controls) participated in this study. The research protocol consisted of a 20-min exertion protocol on stationary bike at 80% (80.98 ± 2.44%) of their theoretical maximal heart rate. Following physical exertion, they performed an experimental Switch task designed to assess executive functions. A series of one-way ANOVAs were performed to compare accuracy (Acc) and response time (RT) between HOC and control athletes on the Switch task. Since the study population was assumed to be heterogeneous, we ran chi-squared tests to determine if there was a group difference in the proportion of participants who underperformed by having a score that was at least 2SD higher (RT) or lower (Acc) than the mean. Results Whilst no significant group difference in performance on the Switch task, the chi-squared test revealed that significantly more HOC athletes (20.6%) underperformed relative to the controls based on their Acc (2.9%; Pearson χ²=5.10, p=0.02). chi-squared test for RT was not significant and no athlete failed both an Acc and RT. Conclusion Although the current results did not support our initial hypothesis that an acute bout of exercise would reveal persistent alterations that were not present at rest, they are in line with previous research indicating cognitive alterations in a minority of athletes (one in five) who sustained a concussion, despite reporting being asymptomatic and be actively participating in their sports. They also highlight the importance of considering inter-individual differences in recovery trajectories with heterogeneous population such as concussed athletes.