0033 THE EFFECTS OF SLEEP RESTRICTION ON SLEEP SPINDLES IN ADOLESCENTS

• Published in: Sleep (New York, N.Y.) N.Y.), 2017-04, Vol.40 (suppl_1), p.A13-A13
• Main Authors: Papalambros, NA, Ong, J, Lo, J, Zee, PC, Chee, MW
• Format: Article
• Language: English
• Subjects: Experiments; Sleep; Teenagers
• ISSN: 0161-8105; 1550-9109
• DOI: 10.1093/sleepj/zsx050.032

Abstract Introduction: Today’s adolescents sleep less than their predecessors. Spindle counts reflect intellectual capacity and are increased during sleep following learning and may be a marker for successful learning. Previous studies indicate that sleep restriction is accompanied by reduced N2 but preserved N3 sleep. Here, we examine changes in spindle count and density during multiple nights of sleep restriction and recovery in adolescents. Methods: Sleep of adolescents aged 15–19 years was monitored with polysomnography during selected nights in two experiments. Experiment 1 consisted of 3 baseline nights (9h time-in-bed [TIB]), followed by 7 nights of either 5h TIB (sleep restriction group; n=25) or 9h TIB (control group; n=22) and 3 recovery nights of 9h TIB. Experiment 2 (n=52) consisted of 2 baseline nights (TIB=9h), 5 nights of 5h TIB, and 2 recovery nights (TIB=9h), with half the participants receiving a 1h daytime nap opportunity after each sleep restriction night. Automatic spindle detection was completed on C3/C4 artifact-free EEG using previously published methods to derive measures of spindle count and density (number/minute) during N2 sleep. All comparisons were to the final baseline night in each experiment. Results: In Experiment 1, spindle count was reduced from 424.8 ± 25.5 (mean±SEM) at baseline to between 233.6 ± 12.1 - 241.3 ± 8.5 during sleep restriction (p0.3), but dropped during recovery (1.8 ± 0.1 vs. 1.5 ± 0.1 nb/min, p=0.001]. Experiment 2 showed a similar pattern in nocturnal spindle characteristics during sleep restriction, although daytime napping reduced spindle count and density during recovery nights [nap: 1.6 ± 0.7 vs. no nap: 1.8 ± 0.5 nb/min, p=0.02]. Conclusion: Among adolescents, despite a reduction in nocturnal spindle count during sleep restriction, the rate of spindle generation remains intact. Additionally, daytime napping reduces spindle count and density in recovery sleep. These characteristics should be taken into consideration when attempting to relate spindle counts and behavior in future studies. Support (If Any): This study was supported by the National Medical Research Council, Singapore (NMRC/STaR/0004/2008 and NMRC/STaR/0015/2013) and The Far East Organization. N.A.P. is supported by NSF GRFP DGE-1324585.