*Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH; †Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; and ‡Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.
OBJECTIVE: Correlational studies have linked short sleep to adolescents' report of postconcussion symptoms and cognitive performance during concussion assessments. This study tested whether those are cause-effect relationships.
DESIGN: Three-week randomly counterbalanced, within-subjects, crossover experiment. SETTING: Adolescents slept at home with weekly visits to an outpatient clinic for sleep monitor uploads and outcome assessments. PARTICIPANTS: Twenty-four healthy 14- to 17.9-year-olds. CONDITIONS: After an initial sleep-stabilization period, adolescents experienced 5-night spans of short sleep (SS; 6.5 hours/night in bed) versus Healthy Sleep Opportunity (HS; 9.5 hours/night in bed). MAIN OUTCOME MEASURES: Cognitive indexes and the postconcussion symptom scale (PCSS) from the Immediate PostConcussion Assessment and Cognitive Testing.
RESULTS: Adolescents reported significantly worse symptoms on the PCSS after SS than HS, even after excluding items manifestly related to sleep. Verbal memory was also worse after SS than HS, though the effect was small. The manipulation did not significantly affect other cognitive indexes.
CONCLUSIONS: A realistic "dose" of short sleep, similar to what many adolescents experience regularly on school nights, can cause or contribute to symptom reports during concussion assessments. Consistent with previous sleep research, one-on-one cognitive tests seem to be less sensitive than measures of emotional and behavioral functioning to the effects of short sleep.