Behavioral Differences Across Sensory Processing Subtypes in Children Ages 6-10 with and without Autism

Background: Previous literature has determined that there is an association between sensory processing difficulties and challenging behaviors in children with autism; specifically, restricted and repetitive behaviors (Chen et al., 2009), stereotyped movements (Gal et al., 2010), and maladaptive behaviors (Lane et al, 2010).  Studies to date, however, have not examined the relative contribution of sensory processing difficulties to variance in challenging behaviors over and above that explained by autism diagnosis alone. Our lab has identified four sensory processing subtypes using the Short Sensory Profile (SSP): 1) no sensory impairment (NSI), 2) taste/smell sensitivity (TSS), 3) postural inattentive (PI), and 4) generalized sensory dysfunction (GSD).  The subtypes are distinct in the sensory modality affected and in the severity of symptoms.   By examining behavior patterns across sensory subtypes we can determine the relative usefulness of sensory features in describing patterns of general behavior when compared to knowledge of autism diagnosis.

Objectives: The purposes of this study were: 1) to better understand the relationship between patterns of sensory responding and general patterns of behavior in children with and without autism, and 2) to compare behavioral differences by sensory subtypes with those by diagnosis. 

Methods: Participants (n=43) were children ages 6-10; 27 were typically developing and 16 were diagnosed with autism.  Each participant was assigned to a sensory subtype using model-based cluster analysis of SSP scores (Lane et al, 2010; 2011). The Nisonger Child Behavior Rating Form (NCBRF) was used to assess each participant’s general behavior, including both problem behavior and positive social behavior.

Results: Preliminary two-way ANOVA revealed significant differences in problem behaviors between subtypes (p=.001) regardless of diagnosis (p=.170). Mean problem behavior scores increased progressively from NSI (fewest sensory symptoms, least problem behaviors) through GSD (most sensory symptoms, most problem behaviors). Post-hoc pairwise comparison with Tukey correction indicated significant differences between NSI and all other clusters, as well as between GSD and all other clusters.  There were no significant differences on problem behaviors between PI and TSS. Two-way ANOVA examining positive social behavior scores revealed no significant difference for subtype (p=.070) and a marginal result for autism diagnosis (p=.052). 

Conclusions: The findings of our study suggest that that sensory subtype may provide additional description of problem behavior patterns in autism than diagnosis alone. We found a clear relationship between sensory subtype and severity of problem behaviors. However, diagnosis of autism may be a better indicator of the presence of positive social behaviors than sensory subtype.  The results of this study provide additional evidence for the utility of sensory features as a means of reducing heterogeneity in autism. One limitation of this study is its small sample size prohibiting the analysis of the relationship between sensory subtypes and specific forms of problem behavior.