Sleep and Developmental Progress in Infants at High-Risk for Autism

Background:  Sleep dysregulation in families raising children with autism spectrum disorder (ASD) is common.  Parents of children with ASD report more sleep problems in themselves, their children with ASD, and in younger siblings.  Although several studies have documented elevated rates of sleep problems, few studies have assessed the developmental correlates of these problems.  The impact of sleep on development is a growing research area with studies of typically developing children noting deficits in language learning, memory, and social competence when sleep is restricted or dysregulated.  Each of these developmental domains are also known areas of difficulty for children at elevated risk for ASD.

Objectives:  This study aimed to assess the associations between sleep regulation and language, social, and visual reception skills within young children at elevated risk for ASD (i.e., infant siblings of children with ASD) across two independent samples.

Methods:  In two samples child actigraph-derived sleep/activity patterns were classified as regulated or dysregulated.  Infant/toddler developmental progress was indexed with the Mullen Scales of Early Learning (MSEL) and the Vineland Adaptive Behavior Scales.  The first sample included 55 toddlers at 24 or 36 months of age (Sample C).  Within this sample, 27 toddlers were younger siblings of children with ASD (high-risk group) and 28 had siblings with no known diagnosis (low-risk group).  The second sample (Sample P) included 118 assessments between 6 and 30 months for 80 children (high-risk group = 41, low-risk group = 39).

Results:  Using sleep time series and multivariate general linear models, children with regulated sleep had higher average MSEL visual reception (VR) and expressive language (EL) scores (β = 1.91, p < .05 and β = 2.03, p = .01, respectively) relative to children with dysregulated sleep (Sample P).  Sleep explained 5% of the variance in VR and 6% of the variance in EL.  In Sample C, there was a statistically significant interaction for sleep with ASD risk status for the MSEL VR scale.  This interaction showed a modest but positive effect of regulated sleep for children in the low risk group (β = 4.38, p = .07) and no significant effect of sleep regulation for children in high risk (β = -1.78, p =.40).   Sleep also interacted with both ASD risk status and child gender for MSEL receptive language (RL) scale.  Sleep was associated with receptive language for children in the low-risk group but not the high-risk group.  Additionally, boys with dysregulated sleep performed on average 7 months lower than their chronological age on the MSEL RL scale (β = 6.88, p < .01).

Conclusions:  In the first three years of life, the present study demonstrated a modest but significant association between sleep regulation and concurrent language and visual reception development.  However, this influence was not robust for infants developing at high risk for ASD.  This may reflect the relative magnitude of the influence sleep has on development.  Infants at elevated risk for ASD face both genetic and environmental risk factors which may have a stronger developmental impact when compared to sleep regulation.