Relationship Between Repetitive Behaviors and Sensory Functioning in ASD

Background: Abnormal sensory functioning is among the most common behavioral concerns of parents of children with autism spectrum disorders (ASD), often causing significant family stress.  Increased abnormal sensory functioning has also been linked to increased repetitive behaviors in this population using parent-report measures (e.g., Baker et al., 2008; Chen et al., 2009), with repetitive behaviors hypothesized to provide some function in self-regulation in the sensory experience. Notably, these reports have relied on parent-reported repetitive behaviors and sensory functioning. Given recently identified performance-pattern differences on measures of vibrotactile detection in ASD (Puts et al., 2013), further investigation into the relationship between performance-based measures of sensory functioning and autism symptomatology is warranted. 

Objectives: To employ a multi-method (parent-report, performance-based) examination of the relationship between sensory functioning and repetitive behaviors in children with autism. 

Methods: Thirty-two children with autism were identified via the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS-G). To measure sensory functioning, parent-report on the Sensory Processing Measure (SPM) and child performance on a vibrotactile battery (e.g., Cortical Metrics-4: CM-4 detection threshold, frequency, amplitude discrimination) was completed.   To measure repetitive behaviors, parent-report on the Repetitive Behavior Scale-Revised (RBS-R) and clinician observation of repetitive behaviors on the ADOS was completed.  The age of the sample ranged from 8-12 years (M=11.0, SD=1.5), and participants were included with at least average intelligence (Wechsler Intelligence Scale for Children-Fourth Edition: WISC-IV Perceptual Reasoning Index: PRI: M=106.8, SD=14.9).  

Results: Significant multi-method correlations were observed between parent-report measures (SPM Total and RBS-R Total: r₂₁ = .631, p = .012) and between performance-based measures (ADOS Repetitive Behaviors and Single Site Amplitude Discrimination: r₂₆ = -.390, p = .049).  Notably, previous reports (Puts et al., 2013) have highlighted performance abnormalities in ASD on the Single Site Amplitude Discrimination task, where amplitude discrimination in typically developing children (TDC) decreases significantly with presentation of single site adaptation, while such effect is not observed in children with ASD.  Cross-method correlations were found for only parent-reported repetitive behavior (RBS Total) and Threshold Detection Reaction Time (r₂₆ = -.400, p = .047).

Conclusions: There are two key findings uncovered by this work: 1) While there is some relationship between vibrotactile response and parent-reported repetitive behaviors, no relationship between vibrotactile response and parent-reported sensory behaviors was established.  2) Children with ASD have been previously shown to perform atypically on the measure of vibrotactile response (Single Site Adaptation) that was found to be correlated with clinician-observed repetitive behaviors. Taken together, these findings provide initial support to suggest overlap between sensory functioning and repetitive behaviors in ASD, and indicate that parent-reported sensory dysfunction in ASD may be more aligned with/reflect general/global behavioral challenges, rather than the specific child sensory experience.