Sensory Processing in Relation to Sleep Disturbances in Young Children with Autism Spectrum Disorder and Fragile X Syndrome with and without Comorbid Autism Spectrum Disorder

Background: Autism Spectrum Disorder (ASD) and fragile X syndrome (FXS) are highly comorbid, with approximately 60% of children with FXS also having ASD (Hagerman, Rivera, & Hagerman, 2008). Children with ASD or FXS are at increased risk for a variety of other challenges, including sensory processing abnormalities and sleep difficulties (Gagnon, & Godbout, 2018). Despite high prevalence of sensory and sleep difficulties in these populations, little is known about how these difficulties may impact one another. Previous studies have linked sensory hyperresponsiveness to sleep difficulties in the typical population (Shochat, Tzischinsky, & Engel-Yeger, 2009); however, this relationship is vastly understudied in those with neurodevelopmental disorders. Given the elevated prevalence of sensory and sleep challenges in these children, examining the association between sensory response patterns and sleep disturbances will shed light on the functional impact of these challenges in those with ASD, FXS and comorbid FXS and ASD.

Objectives: The present study characterizes sensory response patterns across three groups of young children: ASD, FXS-only and FXS comorbid with ASD. This study also investigates the effect of sensory response patterns on sleep disturbances across groups.

Methods: Participants included 18 children with non-syndromic ASD (i.e., nsASD; not associated with a specific syndrome), 16 preschoolers with FXS-only and 11 preschoolers with FXS+ASD between the ages of 36-72 months of age (M = 46.07, SD = 11.48). Clinical best estimate procedures were used to determine presence of comorbid ASD in the FXS+ASD group. Participants’ parents completed the Sensory Experiences Questionnaire (SEQ; Baranek, 1999) as a measure of sensory processing, as well as the Children’s Sleep Habits Questionnaire (CSHQ; Owens, Spirito, & McGuinn, 2000) as a measure of sleep.

Results: Results indicated significant group differences on sensory processing across domains (F(1, 42)=10.61; p<.001), such that the FXS-only group was significantly lower (i.e., better processing) across all sensory domains than both the nsASD and FXS+ASD groups (see Figure 1). Within group bivariate correlations revealed no significant associations between sensory response patterns and sleep scores in any of the groups (p>.05).

Conclusions: Findings suggest that children with nsASD and FXS+ASD experience similar levels of elevated sensory processing difficulties compared to those with FXS-only. Thus, elevated sensory impairments appear to be a shared feature across ASD independent of etiology. Despite group differences in sensory difficulties, no clear association between sensory difficulties and sleep were apparent in any of the groups. Given sample sizes, this may be due to issues with statistical power, or it may be that there are additional underlying mechanisms contributing to sleep difficulties in these populations. The similarities between the nsASD and FXS+ASD groups in their sensory response patterns enhance our understanding of a unique profile between FXS+ASD and FXS-only. These similarities indicate those with FXS+ASD may experience a greater impact on functional outcomes as a result of their elevated sensory processing challenges, and therefore require targeted intervention.