Baseline neurocognitive test results in non-concussed athletes: Does sleep matter?

Abstract

Objectives: When managing sport-related concussions (SRC), sports medicine physicians utilize serial neurocognitive assessments and self-reported symptom inventories when evaluating athlete recovery and safety for returning to play (RTP). Since post-concussive RTP goals include symptom resolution and return to neurocognitive baseline, clinical decisions rest on an understanding of modifiers of baseline performance. Several studies have reported the influence of age, gender and sport on baseline neurocognitive performance, but few have assessed the potential effect of sleep. We hypothesized that: 1) athletes receiving less sleep prior to baseline testing would perform worse on neurocognitive metrics; and 2) decreased sleep would have no association with the quantity of reported symptoms. Methods: We retrospectively reviewed 3,704 non-concussed athletes, 2,385 male, 3,321 high school and 383 college-aged, with baseline symptom and neurocognitive scores on Immediate Post-concussion Assessment and Cognitive Testing (ImPACT). Subjects were stratified into three groups based on self-reported sleep duration the night prior to testing; 1) short < 7 hrs, 2) intermediate 7-9 hrs; and 3) long = 9 hrs). Multivariate analysis assessed the influence of categorical sleep duration on the baseline number of reported symptoms and ImPACT performance, with alpha level of 0.05. Results: When controlling for age, gender and sport as covariates, the multivariate analysis of covariances showed a significant association between shorter sleep duration and poorer verbal memory scores (p=0.019), visual memory scores (p=0.035), and reaction time scores (p=0.044), but not for visual-motor scores. Significance was found between shorter sleep duration and increased number of reported symptoms (P < 0.0001). Subsequent pairwise comparisons revealed these associations to be most significant when specifically comparing the short and intermediate sleep groups. Conclusion: Our results indicate that athletes sleeping less than 7 hours prior to testing perform worse on 3 out of 4 neurocognitive ImPACT scores and endorse more symptoms. Because concussion management and RTP decisions hinge on the comparison to a reliable baseline evaluation, sports medicine physicians should strongly consider amount of sleep prior to neurocognitive testing in the assessment of athletes’ recovery.