0261 Shifting Circadian Phase and School-night Bedtime Earlier Improves Visual Creativity and Inhibition in Adolescents. (12th April 2019) - Velez, Sabrina L
Abstract: Introduction: Many adolescents fall asleep too late to obtain sufficient sleep on school nights. Bright morning light can advance circadian rhythms, facilitating earlier sleep times and longer sleep. We are testing whether these interventions can improve executive functions in late and short-sleeping adolescents attending high school. Methods: So far, 32 healthy adolescents (14.6-17.9 years; 16 female) completed a four-week study, in which they were randomly assigned to a control ( n =17) or intervention ( n =15) group. Following two weeks of usual home sleep, participants lived in the lab for a weekend. On Friday night, a 9-h sleep opportunity ended at average school-day wake. On Saturday (09:00, 10:00, or 12:30) participants completed five measures from the Delis-Kaplan Executive Function System (D-KEFS), a paper-and-pencil neuropsychological battery that assesses components of executive function. During the subsequent two weeks, intervention participants were assigned earlier school-night bedtimes; 1-h and 2-h advance during weeks three and four, respectively. During the intervening weekend, intervention participants received 2.5h intermittent bright light from light boxes (~6000lux) on both mornings in the laboratory to advance circadian rhythms. The control group was not given instruction about bedtimes and did not receive morning bright light. The D-KEFS was repeated during the Saturday of a final lab weekend at the same time as before. Time-by-group interactions from repeated measures ANOVAs are reported. Results: Color Word inhibition performance improved in the intervention group, but not in the control group, F (1, 30)=5.05, p =.03. Design Fluency scores increased in both groups, but more in the intervention group, F (1, 31)=4.68, p =.04. Circadian phase advanced 50 mins, sleep onset advanced 89 mins, and total sleep time increased 68 mins in the intervention group, but remained unchanged in the control group (see companion abstract by Crowley et al). Conclusion: Two weeks of advancing circadian rhythms and bedtimes (making them earlier) and increasing sleep duration in adolescents produced better executive functioning performance in the domains of inhibition and visual creativity. These data have implications for academic performance and healthy decision making in adolescents. Support (If Any): R01HL105395 (S.J.C.)