Sensory Processing, Repetitive Behaviours and Anxiety in Autism Spectrum Disorder and Williams Syndrome

Background: Unusual sensory responses are common in autism spectrum disorder (ASD) and have been included in the diagnostic criteria for the disorder, alongside social communication and interaction difficulties. Sensory difficulties, are also common amongst individuals with other neurodevelopmental disorders, including Williams syndrome (WS). Interestingly, both disorders although with different aetiology and presentations, share not only psychopathology relating to sensory processing, but also repetitive behaviours and anxiety. The associations, however, within and between these features are still not well understood and the degree of the co-occurrence and syndrome-specificity is still not well characterised.

Objectives: The aims of this study were: (a) to examine and compare the features of sensory processing clusters in children with ASD or WS; (b) to investigate whether sensory processing based clusters differed according to levels of anxiety and repetitive behaviours in children with ASD or WS.

Methods: Parents of 17 children with ASD and 16 with WS, aged between 4 and 9 years were recruited. Parents were asked to complete the Sensory Profile to provide information about their children’s sensory experiences, the Social Responsiveness Scale (SRS-2) to assess a degree of social impairment, the Spence Children’s Anxiety Scale/Preschool Anxiety Scale (SCAS/PAS) and the Anxiety Scale for Children-ASD (ASC-ASD) to assess anxiety symptoms, and the Repetitive Behaviour Questionnaire to evaluate the severity or frequency of repetitive behaviours that the children were engaging in.

Results:  A hierarchical agglomerative cluster analysis was performed in order to identify subgroups based on sensory characteristics (Low Registration, Sensory Sensitivity, Sensation Seeking, Sensory Avoiding). A two-cluster solution emerged as the best fit to the data when the total sample was entered and also when ASD and WS groups were entered separately. Cluster 1 was represented with a low frequency of sensory behaviours and (2) cluster with a high frequency of sensory behaviours. A MANOVA showed a significant cluster effect for total repetitive behaviour score and both subscales (repetitive sensory motor behaviours and insistence on sameness; F(3,27)=6.56, p=.002). In addition the clusters differed on all total and subscale anxiety scores (SCAS/PAS scores F(6,24)=4.10, p=.006; ASC-ASD F(4,23)=3.64, p=.019). Univariate analysis indicated that parents of children in cluster 2 reporting significantly more repetitive behaviours and higher levels of child’s anxiety than parents of children in cluster 1. However, when the SRS-2 total score was controlled for only the effect of cluster on anxiety remained significant for the SCAS/PAS scores in the total sample F(6,23)=2.74, p=.037.

Conclusions: The findings suggest that sensory profiles in children with WS or ASD are similar and that sensory processing atypicalities are associated with higher levels of anxiety and repetitive behaviours in both disorders. However, differences in severity of autistic traits contribute to the higher presentation of repetitive behaviours and anxiety in those children with ASD and WS who have greater sensory difficulties. Further work is needed to explore the role of other possible factors (e.g. intolerance of uncertainty) in the presentation of sensory atypicalities, repetitive behaviours and anxiety in neurodevelopmental disorders.