The Influence of Restricted Repetitive Behaviors on the Relationship between Autism Symptom Severity and Sleep Problems in Children

Background:

Many studies have documented increased sleep problems in children with autism spectrum disorder (ASD) when compared to their typically developing peers⁴. Research has reported mixed results in terms of the correlation between ASD symptom severity and increased sleep problems³. Specifically, some studies found that ASD severity was positively correlated with sleep problems; while others did not find this correlation^2,4. This study examined the role of restricted, repetitive behaviors (RRBs) as a possible mediator of the relationship between sleep problems and ASD symptomatology.

Objectives:

1. Is there a difference on reported sleep problems between children with high versus low ASD severity?
2. Is there a relationship between RRBs, ASD severity, and sleep problems in children with autism? If so, do RRBs mediate the association between ASD severity and sleep problems?

Methods:

Participants included children who were screened for ASD at a university research center in the Inland Southern California. From this sample, 148 children with ASD under the age of five (M= 3.91, SD= 1.04, range 1.60-5.80) were included. Intelligence quotient (IQ) had a mean of 69.15 (17.90) with a range of 41-120. Most children were male (30 female) and 48.6% were Hispanic (23.6% Caucasian; 21.6% other; 4.1% African American; .7% Asian, 1.4% declined).

Data were collected from the following measures: Autism Diagnostic Observation Schedule—Second Edition (ADOS-2), Child Behavior CheckList (CBCL), and Social Responsiveness Scale (SRS). Sleep problems scores were derived from the CBCL t-scores. ASD calibrated severity scores (CSS) were derived from the ADOS-2 comparison score. Participants with a CSS of 4 or 5 were considered low severity and those with a CSS of 6 to 10 were considered moderate/high severity. RRBs were determined by the Autistic mannerisms/RRBs subscale t-score of the SRS.

Results:

Correlations were conducted to examine the differences in sleep problems between participants with high and low CSS. A negative correlation was found between CSS and sleep problems (p = .04). Correlations were also conducted for RRBs, ASD severity, and sleep problems. Positive correlations were found between RRBs and sleep problems (p < .01). No correlations were found between RRBs and CSS.

To examine the possible impact of RRBs (M) on the relationship between CSS scores (X) and sleep problems (Y), while for controlling for IQ, internalizing and externalizing problems, a mediation Model 4 was conducted using the SPSS PROCESS plug in¹. The indirect effect was not significant, (95% CI = [-1.33, 2.58]), such that RRBs do not mediate the relationship between CSS and sleep problems.

Conclusions:

Findings from this study add to the existing literature on sleeping difficulties in children with ASD. In particular, this study provides insight into the relationship between RRBs, sleep problems, and ASD severity. Although RRBs did not mediate the relationship between CSS and sleep problems, both RRBs and CSS were correlated with sleep problems. Moreover, this also underscores the need to consider RRBs in interventions targeting sleep problems.