Evaluation of an interactive school-based sleep education program: a cluster-randomized controlled trial.

OBJECTIVES: Shortened sleep has negative consequences on adolescents' well-being. The present study evaluated an interactive school-based sleep education program (SEP) aimed at increasing adolescent sleep duration. DESIGN AND INTERVENTION: A cluster-randomized controlled trial with 12 clusters (classes) was used. The intervention group received a SEP and the active control group received a healthy living program (HLP). Both groups underwent a 4-week class-based education program. The SEP students learned about the importance of sleep, the barriers to getting enough sleep, and how to improve their time management to increase their sleep opportunity. The HLP students learned about various health-related topics not including sleep. PARTICIPANTS: A total of 210 students (mean age = 14.04 ± 0.32 years) were randomly assigned to the SEP (n = 102) or the HLP (n = 108) group, with 6 classes per group. MEASUREMENTS: Sleep (actigraphically measured), sleep knowledge, and time usage were assessed using linear mixed models at three time points: baseline, immediately after intervention, and 1-month follow-up. RESULTS: Sleep knowledge improved at follow-up in the SEP relative to the HLP group (p = .017). Although students were receptive of the program and self-reported the intention to create more time for sleep, no changes in sleep were found following the SEP. Some benefit may have been masked by exam preparations at the follow-up evaluation. CONCLUSIONS: Sleep education alone may not be sufficient to change sleep behavior. A combination of sleep education, starting school later, and parental involvement may be needed to encourage and enable changes in adolescent sleep duration.

Sleep improves memory for the content but not execution of intentions in adolescents.

OBJECTIVE: Sleep benefits prospective memory in young adults probably in part due to its well-established role in enhancing declarative memory, thereby facilitating retrieval of the intention content. In prior work on adolescents, we did not detect differences in prospective memory comparing five nights of sleep restriction and adequate sleep. Here, we examined whether this might be attributed to a limited role of sleep in benefiting the declarative content in this age group, and whether a sleep benefit on prospective memory would be uncovered with a shorter retention interval. METHODS: A total of 59 adolescents (mean ± standard deviation: 16.55 ± 0.94 years) were instructed to remember to press a special key in response to two target words embedded in a semantic categorization task. Memory was tested after a 12-h retention interval, which included either overnight sleep (21:00-09:00, n = 29) or daytime wakefulness (09:00-21:00, n = 30). RESULTS: We found no significant group difference in the percentage of target words correctly responded to (mean ± standard error of the mean for the sleep group: 32.76 ± 6.69%; wake group: 41.67 ± 7.61%, t = 0.88, p = 0.38). However, participants who slept recalled more target words compared to those who stayed awake (98.28 ± 1.72% vs. 86.67 ± 5.32%, t = 2.05, p < 0.05). In addition, a significantly greater proportion of sleep participants (n = 28 of 29) compared to wake participants (n = 24 of 30) recalled both target words correctly (χ2 = 3.76, p < 0.05). CONCLUSION: These findings suggest that during adolescence, sleep plays a more prominent role in improving memory for the content as compared to the execution of intentions.

Slow wave sleep facilitates spontaneous retrieval in prospective memory.

STUDY OBJECTIVES: Previous studies have shown that sleep benefits prospective memory by facilitating spontaneous retrieval processes. Here, we investigated the sleep features supporting such a benefit. METHODS: Forty-nine young adults (mean age ± SD: 22.06 ± 1.71 years; 18 males) encoded intentions comprising four related (phone-unplug earphones) and four unrelated (mirror-close the book) cue-action pairs. They were instructed to remember to perform these actions in response to cue words presented during a semantic categorization task 12 h later. The retention interval involved either a period of wakefulness (09:30-21:30; n = 24) or overnight sleep with polysomnographic monitoring (21:30-09:30; n = 25). RESULTS: We found a significant Group × Relatedness interaction for prospective memory accuracy (F = 8.35, p < 0.01). The sleep group successfully executed a significantly higher percentage of related intentions compared to the wake group (mean ± standard error of the mean (SEM): 94.00 ± 2.61% vs 66.67 ± 6.84%, p < 0.001). This benefit for related intentions was associated with longer post-learning slow wave sleep (r = 0.46, p < 0.05). In contrast, the percentage of unrelated intentions successfully executed did not differ between groups (82.00 ± 5.10% vs 72.92 ± 6.88%, p = 0.29). CONCLUSION: Slow wave sleep after memory encoding may strengthen the preexisting associations between semantically related cues and actions, thereby facilitating subsequent spontaneous retrieval processes.

Multiple nights of partial sleep deprivation do not affect prospective remembering at long delays.

Prospective memory is defined as remembering to do something at a particular moment in the future and may be modulated by sleep. Here, we investigated whether multiple nights of partial sleep deprivation would affect the successful retrieval of intentions. Fifty-nine adolescents (mean age ± SD: 16.1 ± 0.6 years) were instructed to remember to press specific keys in response to the target words presented during a semantic categorization task in the future. Their memory was tested after five nights of either 5-h (sleep restriction group) or 9-h time-in-bed (control group). The average percentage of target words correctly responded to was small and did not significantly differ between the two groups (mean ± SEM for the sleep restriction group: 15.52 ± 6.61%; the control group: 23.33 ± 7.48%, p = 0.44). Thus, after the extended retention interval, prospective remembering was poor and did not appear to be affected by post-learning sleep restriction. These findings suggest a temporal boundary beyond which intentions fall below requisite levels of activation, potentially masking any benefits for retrieval conferred by sleep.