Relationships between Sensory Atypicalities, Repetitive Behaviours, Anxiety and Intolerance of Uncertainty

Background: Unusual sensory responses are common in autism spectrum disorder (ASD) and a subcategory of atypical sensory behaviours has been included in the restricted, repetitive patterns of behaviour, interests, or activities diagnostic criterion (APA, 2013). Not only has a high degree of co-occurrence between sensory atypicalities and repetitive behaviours been reported in a number of studies (for the review see Glod et al., 2015), but interestingly, repetitive behaviours and sensory atypicalities have been linked to anxiety (Green et al., 2011; Lidstone at al., 2014; Wigham et al., 2015) and intolerance of uncertainty (Wigham et al., 2015) in ASD. The associations, however, are still not well understood and the degree of co-occurrence of these features is still not fully explored.

Objectives: The aim of this study was to examine the relationships between sensory atypicalities, repetitive behaviours, anxiety and intolerance of uncertainty in autistic children to better understand the complexity of the disorder and its pathogenesis.

Methods: Parents of 17 autistic children, 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 to assess a degree of social impairment, the Spence Children’s Anxiety Scale/Preschool Anxiety Scale and assess anxiety symptoms, the Repetitive Behaviour Questionnaire to evaluate the severity or frequency of repetitive behaviours that the children were engaging in and the uncertainty subscale of the Anxiety Scale for Children-ASD to measure children’s level of intolerance of uncertainty.

Results: Serial mediation analysis was performed using PROCESS (Hayes, 2012). The model was based on previous computational work (Wigham et al., 2015): direct paths from both sensory hyporesponsiveness and sensory hyperresponsiveness to both repetitive sensory/motor behaviours and insistence on sameness and an indirect path through intolerance of uncertainty and anxiety were tested. The significant total and direct effects were found: from sensory hyporesponsiveness to repetitive sensory/motor behaviours (β=-.12, p=.003 and β=-.14, p=.018 respectively) and insistence on sameness behaviours (β=-.17, p<001 and β=-.19, p=.007); and from sensory hyperresponsiveness to repetitive sensory/motor behaviours (β=-.13, p=.002 and β=-.11, p=.031) as well as to insistence on sameness (β=-.17, p=.001 and β=-.13, p=.040). Moreover, significant indirect effects through anxiety (β=-.09, LL=-.21, UL=-.00) and intolerance of uncertainty and anxiety (β=.19, LL=.02, UL=.46) from sensory hyporesponsiveness to insistence on sameness behaviours were found.

Conclusions: Significant direct relationships were found between sensory features and repetitive behaviours. Yet, all the paths between sensory processing abnormalities and repetitive behaviours were partially mediated by at least one of the mediation variables (intolerance of uncertainty or anxiety). Significant indirect relationship between sensory hyporesponsiveness and insistence on sameness behaviours was mediated via anxiety, and intolerance of uncertainty and anxiety. The important mediating role of anxiety and intolerance of uncertainty between sensory atypicalities and repetitive behaviours in ASD needs to be taken into account in sensory processing and repetitive behaviours treatment programmes for young children with ASD.