Athletes' results on a concussion test declined with the number of hours of sleep the night before the test, results of a large retrospective study showed.
Fewer than 7 hours of sleep the night before correlated with significantly worse performance on assessments of verbal memory, visual memory, and reaction time, reported D. Jake McClure, a medical student at Vanderbilt University in Nashville, Tenn., and colleagues.
However, scores of a test of visual-motor skills were not affected by sleep duration, they said at a presentation at the American Orthopaedic Society for Sports Medicine meeting in Chicago.
None of the 3,704 athletes tested had concussions, but the number of reported symptoms increased as sleep duration decreased.
"Because return-to-play decisions often hinge on the comparison of post-concussion to baseline concussion scores, our research indicates that healthcare providers should consider the sleep duration prior to baseline neurocognitive testing as a potential factor in assessing recovery," McClure said in a statement.
Sports medicine specialists rely on results of a battery of neurocognitive assessments and self-reported symptoms to evaluate recovery from concussion and ensure that athletes can safely return to participation. An accurate assessment requires an understanding of factors that can influence test scores.
Age, sex, and type of sport have been associated with baseline neurocognitive performance, but little information is available on the potential impact of sleep on test performance. McClure and colleagues hypothesized that less sleep prior to baseline testing would adversely affect test scores but would not be associated with self-reported symptoms.
Investigators retrospectively reviewed records of 2,385 male athletes' and 1,319 female athletes' baseline symptoms and results on the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery (3,305 high-school age and 381 college-age participants).
The assessment comprises four areas of neurocognitive performance: verbal memory, visual memory, reaction time, and visual-motor (information processing) performance.
Self-reported symptoms and test scores were compared with self-reported duration of sleep the night before the baseline test. McClure and colleagues stratified sleep duration into three categories: <7 hours, 7 to 9 hours, and >9 hours.
In a multivariate analysis that controlled for age, sex, and type of sport, sleep duration <7 hours had significant associations with ImPACT scores related to visual memory (P=0.035), verbal memory (P=0.019), and reaction time (P=0.044). Scores on visual-motor testing did not vary significantly by sleep duration the night before testing. Shorter sleep duration had a significant inversion association with athletes' self-reported symptoms (P<0.0001).
Pairwise comparisons showed that the relationship of sleep duration to test performance and symptoms was strongest for the comparison between the short- and intermediate sleep-duration categories.
"Understanding factors which modify baseline testing, potentially including sleep, will continue to help lead to more accurate concussion testing, which ultimately equips clinicians with the best judgment to avoid returning athletes to competition earlier than necessary," McClure said.
American Orthopaedic Society for Sports MedicineSource Reference: McClure DJ, et al "Baseline neurocognitive test results in noncussed athletes: Does sleep matter?" AOSSM 2013; Abstract 28.