Sensory Seeking Behaviors and Orientation to Social and Non-Social Sensory Stimuli In Infant Siblings of Children with Autism Spectrum Disorders

Background: Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by social and communicative deficits along with repetitive behaviors and restricted interests. Although not included in the diagnostic criteria, atypical sensory processing has been observed in many individuals with ASD from infancy to adulthood. The study of sensory processing in infants at risk for ASD, such as infant siblings of children with ASD (sibs-ASD), may be particularly important as sensory processing atypicalities in infancy could have considerable downstream effects on the development of complex social, language, and cognitive skills. Further, atypical sensory processing in sibs-ASD may be a useful endophenotype in understanding the genetic etiology of ASD.

Objectives: The primary aim of the current study is to examine sensory seeking behaviors in sibs-ASD and infant siblings of typically-developing children (sibs-TD) using a standardized measure, the Sensory Processing Assessment (SPA), and to investigate how these behaviors may affect orienting to social and non-social stimuli.

Methods: This study included 12 sibs-ASD and 18 sibs-TD recruited at approximately 18 months of age (sibs-ASD: M = 18.35, SD = 0.61; sibs-TD: M = 18.43; SD = 0.34, t (28)= 0.50 p > .63). All ASD diagnoses of older siblings were confirmed by a clinical psychologist using the ADOS and ADI-R. The SPA is a play-based assessment that includes items for sensory approach/avoidance and seeking behaviors, as well as habituation and orientation items that are presented while the child is engaged with the sensory stimuli. The measures of interest in the current study were: 1) sensory and repetitive behaviors (e.g., flapping, sighting, posturing, spinning) in response to visual, auditory, and tactile stimuli (‘sensory seeking’); and 2) orienting to social stimuli (e.g., wave, name call, shoulder tap) and non-social stimuli (e.g., lights, sound, air puff) presented across visual, auditory, and tactile modalities. All videos were consensus-coded by two trained observers who were blind to diagnostic status.

Results: Relative to the sibs-TD, the sibs-ASD group demonstrated a greater intensity, t (28) = -2.86, p = .008,  and a larger inventory of sensory seeking behaviors, t(28)= -3.28, p = .003. Although no group differences were detected in social and non-social orienting measures from the SPA, the intensity of sensory seeking across both groups was found to be significantly correlated with a failure to orient to social, r =  .59, p = .01, and non-social stimuli, r = .41, p = .03. A greater inventory of sensory seeking behaviors was also found to be related to a failure to orient to social stimuli, r = .51, p = .004, yet this relationship was not significant for non-social stimuli, r = .25, p = .19.

Conclusions: The results of this study suggest that sibs-ASD as young as 18 months engage in sensory seeking behaviors to a greater extent than sibs-TD and that these behaviors are associated with their ability to orient to salient social and non-social stimuli in the environment. This tendency may ultimately cause sibs-ASD to miss important opportunities for social interaction and learning over the course of development.