Sensory Processing Abnormalities of Children with Autism Spectrum Disorder

Background:  Sensory abnormalities in children with Autism Spectrum Disorder (ASD) were described in the original papers of Kanner and Asperger. Subsequent studies have suggested that children with ASD exhibit significantly more sensory processing deficits than children with other developmental disorders and show impairment across sensory domains.  Few of these studies have been based on large, well-defined populations. 

Objectives:  This study was conducted to estimate the prevalence of sensory abnormalities in a diverse, population-based sample of eight-year-old children with ASD in metropolitan New Jersey and to identify any demographic differences in the expression of sensory abnormalities. 

Methods:  

This study was conducted as a comprehensive, retrospective analysis of New Jersey Autism Study (2010) data. ASD ascertainment was by the Centers for Disease Control and Prevention (CDC) active, multiple source, case-finding method, using the DSM-IV-TR-based ASD diagnostic criteria.  Reports of sensory abnormalities were recorded in comprehensive medical and educational evaluations and analyzed during the process of ASD case ascertainment.  Sensory abnormalities were defined as odd responses to sensory stimuli, such as sounds, smells, or vestibular movement; atypical focus on sensory input, or persistent, odd responses to sensory stimuli, as indicated in one or more professional evaluations conducted before age nine, consistent with the Autism and Developmental Disabilities Monitoring (ADDM) Network definitions and standards. Demographic data came from the source records.  Race/ethnicity categories were: white (non-Hispanic), African-American (non-Hispanic) and Hispanic. Cognitive level was defined by intellectual quotient (IQ) from standard tests recorded in the source records.  Frequency, distributions, and Chi-square tests were calculated using SAS software.

Results:  We identified 432 (62%) ASD-confirmed eight-year-old children with documented indication(s) of sensory abnormalities, reported in comprehensive educational and/or medical evaluations, from a total population of 696 ASD children residing in metropolitan New Jersey. The expression of sensory abnormalities in children with ASD did not vary significantly by sex (male to female ratio 5.6:1), cognitive functioning (IQ) or degree of impairment.  However, the expression of sensory abnormalities significantly varied by race/ethnicity (p<.001). White children (70%) were more likely to have sensory abnormalities documented in their records than African-American children (62%) and Hispanic children (50%).  Twelve percent of ASD children with sensory abnormalities were diagnosed with Sensory Integration Disorder (SID).

Conclusions:  

Previous studies have reported that 76% - 95% of ASD children exhibit sensory abnormalities.  Our findings, based on population-based data from a large and diverse region, indicate that approximately 62% of all ASD children have sensory abnormalities reported on professional evaluations, before age nine.  The observed ethnicity-based difference in the expression of sensory abnormalities in children with ASD was unexpected and may reflect cultural differences in the reporting of ASD features by Hispanic families and/or by professionals.  Additional research is needed to clarify this question and to consider the relation of sensory abnormalities to core ASD features.