First night effect analysis in a cohort of young children with autism spectrum disorder.

STUDY OBJECTIVES To evaluate for the first night effect (FNE) in a group of young children with autism. DESIGN Analysis of polysomnographic data from a 2-night sleep laboratory study. SETTING Clinical Center of the National Institutes of Health. PATIENTS OR PARTICIPANTS 15 children (aged 2-10 years) with a diagnosis of an ASD. INTERVENTIONS None. MEASUREMENTS AND RESULTS Polysomnographic analysis showed the presence of a FNE for wake after sleep onset minutes, stage 2, and sleep efficiency, but not for REM sleep parameters or TST. CONCLUSIONS In this 2-night polysomnographic analysis of sleep stages in young children with autism, we did not find the expected second night increase in total sleep time or REM sleep percentage or a decrease in REM sleep latency. This lack of an FNE for TST and REM parameters suggests that a single-night polysomnogram may be sufficient to evaluate children with an ASD for TST or REM parameters.