Delayed school start time is associated with better sleep, daytime functioning, and life satisfaction in residential high-school students.

The effects of a delayed school start time by one hour were examined at a boarding school in Hong Kong. Two cohorts of high school students (N = 228; 61.8% female) were recruited respectively before and after a school start time changed from 7:30am to 8:30am. Both cross-cohort and within-cohort longitudinal comparisons yielded significant increase in total sleep time. Cross-cohort comparison yielded improvement in sleep quality, insomnia, life satisfaction, and psychological distress. Longitudinal data suggested that the longer the additional sleep time, the better was sleep quality, day-time functioning, and subjective wellbeing.

Working memory impairment and its associated sleep-related respiratory parameters in children with obstructive sleep apnea.

STUDY OBJECTIVE: Working memory deficits in children with obstructive sleep apnea (OSA) have been reported in previous studies, but the results were inconclusive. This study tried to address this issue by delineating working memory functions into executive processes and storage/maintenance components based on Baddeley's working memory model. METHODS: Working memory and basic attention tasks were administered on 23 OSA children aged 8-12 years and 22 age-, education-, and general cognitive functioning-matched controls. Data on overnight polysomnographic sleep study and working memory functions were compared between the two groups. Associations between respiratory-related parameters and cognitive performance were explored in the OSA group. RESULTS: Compared with controls, children with OSA had poorer performance on both tasks of basic storage and central executive components in the verbal domain of working memory, above and beyond basic attention and processing speed impairments; such differences were not significant in the visuo-spatial domain. Moreover, correlational analyses and hierarchical regression analyses further suggested that obstructive apnea-hypopnea index (OAHI) and oxygen saturation (SpO2) nadir were associated with verbal working memory performance, highlighting the potential pathophysiological mechanisms of OSA-induced cognitive deficits. CONCLUSIONS: Verbal working memory impairments associated with OSA may compromise children's learning potentials and neurocognitive development. Early identification of OSA and assessment of the associated neurocognitive deficits are of paramount importance. Reversibility of cognitive deficits after treatment would be a critical outcome indicator.