RESUMEN
Insufficient sleep negatively impacts scholastic performance in children and adolescents. Here we use a dose response time in bed (TIB) restriction study to evaluate associations between sleep loss and multiple aspects of cognition. We evaluated changes in cognitive measures across ages 10 to 23 years and determined whether the effects of sleep loss changed across this age range. A younger cohort (n=77, age range 9.9 to 16.2 years) was studied annually for 3 years. An older cohort study (n=82, age range 15 to 22.8 years) was interrupted by the COVID pandemic with 25 participants completing multiple years. Annually participants completed each of three TIB conditions: four consecutive nights with 7, 8.5, or 10 h in bed. A day of cognitive testing followed the fourth night. Restricting TIB to 7 h was associated with impaired top-down attentional control and cognitive flexibility, but performance did not differ between the 8.5 and 10 h TIB conditions. Psychomotor vigilance test performance decreased as TIB was restricted from 10 to 8.5 h and decreased further with restriction to 7 h. Sternberg test measures of working memory were not significantly affected by TIB restriction. The effects of sleep loss on these cognitive measures did not change significantly with age, but age-related improvement in many of the measures may compensate for some sleep loss effects. The findings here do not indicate an adolescent decrease in sleep need; however, the minimal duration of sleep needed for optimal performance appears to differ depending on the cognitive measure.
RESUMEN
STUDY OBJECTIVES: The teenage increase in sleepiness is not simply a response to decreasing nighttime sleep duration. Daytime sleepiness increases across adolescence even when prior sleep duration is held constant. Here we determine the maturational trend in daytime sleep propensity assessed with the multiple sleep latency test (MSLT) and assess the trend's relation to pubertal maturation and changes in the sleep electroencephalogram. We also evaluate whether the relation of daytime sleep propensity to prior sleep duration changes between ages 10 and 23 years. METHODS: Participants (nâ =â 159) entered the study between ages 9.8 and 22.8 years and were studied annually for up to 3 years. Annually, participants kept each of three sleep schedules in their homes: 7, 8.5, and 10 hours in bed for 4 consecutive nights with polysomnography on nights 2 and 4. MSLT-measured daytime sleep propensity was assessed in the laboratory on the day following the fourth night. RESULTS: A two-part linear spline model described the maturation of daytime sleep propensity. MSLT sleep likelihood increased steeply until age 14.3 years, after which it did not change significantly. The maturational trend was strongly associated with the adolescent decline in slow-wave (delta, 1-4 Hz) EEG power during NREM sleep and with pubertal maturation assessed with Tanner stage measurement of breast/genital development. The effect of prior sleep duration on sleep likelihood decreased with age. CONCLUSIONS: Adolescent brain changes related to pubertal maturation and those reflected in the delta decline contribute to the adolescent increase in daytime sleep propensity.
Asunto(s)
Trastornos de Somnolencia Excesiva , Sueño , Humanos , Adolescente , Sueño/fisiología , Polisomnografía , Electroencefalografía , Vigilia/fisiologíaRESUMEN
BACKGROUND AND OBJECTIVES: Sleep duration decreases by â¼10 minutes per year throughout adolescence. A circadian phase delay and changes in homeostatic sleep regulation enable adolescents to stay up later. We determine if teens are able to increase sleep duration by advancing bedtime and whether this ability changes with age. METHODS: A younger cohort of 77 participants ranging in age from 9.9 to 16.2 years were studied annually for 3 years. An older cohort of 67 participants ranging in age from 15.0 to 20.6 years was studied only once. Annually, participants kept each of 3 different time in bed (TIB) schedules (7, 8.5, and 10 hours) for 4 consecutive nights. Participants kept their habitual weekday rise times; TIB was altered by advancing bedtimes. We report polysomnography-measured sleep durations from the fourth night of the TIB schedule. RESULTS: Despite increases in sleep onset latency and wake after sleep onset, sleep duration increased with TIB as bedtime was advanced. Average (SE) sleep duration increased from 402.8 (1.6) minutes with 7 hours to 470.6 (2.1) minutes with 8.5 hours to 527.5 (3.0) minutes with 10 hours TIB. Sleep duration decreased with age (1.55 [0.48] minutes/year), but the TIB effect on sleep duration did not (TIB by age interaction, P = .42). CONCLUSIONS: Adolescents can substantially increase sleep duration by advancing bedtime, and this ability does not change between ages 10 and 21 years. Additional research is needed to determine how to translate these findings from experiment-controlled sleep schedules to real-world sleep duration increases.
Asunto(s)
Duración del Sueño , Sueño , Humanos , Adolescente , Niño , Adulto Joven , Adulto , Sueño/fisiología , Polisomnografía , Factores de Tiempo , HomeostasisRESUMEN
STUDY OBJECTIVES: This report describes findings from an ongoing longitudinal study of the effects of varied sleep durations on wake and sleep electroencephalogram (EEG) and daytime function in adolescents. Here, we focus on the effects of age and time in bed (TIB) on total sleep time (TST) and nonrapid eye movement (NREM) and rapid eye movement (REM) EEG. METHODS: We studied 77 participants (41 male) ranging in age from 9.9 to 16.2 years over the 3 years of this study. Each year, participants adhered to each of three different sleep schedules: four consecutive nights of 7, 8.5, or 10 h TIB. RESULTS: Altering TIB successfully modified TST, which averaged 406, 472 and 530 min on the fourth night of 7, 8.5, and 10 h TIB, respectively. As predicted by homeostatic models, shorter sleep durations produced higher delta power in both NREM and REM although these effects were small. Restricted sleep more substantially reduced alpha power in both NREM and REM sleep. In NREM but not REM sleep, sleep restriction strongly reduced both the all-night accumulation of sigma EEG activity (11-15 Hz energy) and the rate of sigma production (11-15 Hz power). CONCLUSIONS: The EEG changes in response to TIB reduction are evidence of insufficient sleep recovery. The decrease in sigma activity presumably reflects depressed sleep spindle activity and suggests a manner by which sleep restriction reduces waking cognitive function in adolescents. Our results thus far demonstrate that relatively modest TIB manipulations provide a useful tool for investigating adolescent sleep biology.