VARIABILITY OF SLEEP IN PRESCHOOLERS: IMPACTS OF SLEEP BEHAVIORS ON BRAIN PROCESSING AND BEHAVIORAL TASK PERFORMANCE

Victoria J. Molfese, PhD and Dennis L. Molfese, PhD, Child, Youth and Family Studies, University of Nebraska-Lincoln, Lincoln, NE.

Regular sleep periods are related to young children’s cognitive processing and behavioral task performance. However, some sleep schedules are disrupted by family activities creating bedtime delays (delayed sleep) and in other cases children get longer sleep times (extended sleep), such as sleeping later on weekends. Variabilities in sleep compared to a child’s typical sleep are thought to be sources of behavioral disruptions. We report findings from related sleep studies with toddlers and young children. Sleep has been less studied in young children, compared to sleep studies of older children, youth and adults. Our first project characterized sleep habits of toddlers (30-months to 42-months) by measuring bedtime, sleep onset, sleep offset, sleep duration [time from sleep onset to sleep offset], nighttime wakefulness, and sleep efficiency [true sleep / sleep duration] based on parent reports and actigraph measures. Parents over-report toddler’s sleep duration and sleep efficiency, and under-report toddler’s evening sleep onset and nighttime wakefulness. These reporting biases may have methodological and parenting implications. Further, delayed sleep (e.g., bedtime, sleep onset) specifically was found to impact cognitive task performance over time. The second study examined purposeful variations in amounts of sleep to determine impacts of brain processing during executive function tasks in children 5 to 8 years of age. Sleep loss (1 hour less sleep per night for 1 week) impacted brain activation patterns; more brain areas and longer processing time was needed to perform the Stroop test. Extended sleep revealed a more complex pattern of results with implications for sleep schedules.</p><p>Funding: The National Institute for Child Health and Human Development (grant number HD073202).