The Difference in Sensory Processing Between Children with and without ASD

Background:  Autism spectrum disorder (ASD) is a very heterogeneous condition. Sensory processing abnormalities are common and can be detected very early. Several methods exist to assess these abnormalities; the most accessible ones rely on description of behavioral responses to different stimuli.

Objectives:  to describe the differences in sensory processing between  children with and without ASD.

Methods:  

A case-control study was conducted from July 2014 to August 2015, at the Child and Adolescent Psychiatry Unit at the University Hospital of Monastir. We included all outpatients diagnosed with ASD seen during their routine follow-up. A control group was chosen randomly in 4 different kindergarten of the region of Monastir. Each group included 100 children, with a sex ratio M/F of 4.2 and a mean age of 3.2 years. ASD was diagnosed according to DSM-IV criteria by certified Child and Adolescent Psychiatrists and the Childhood Autism Rating Scale (CARS). We excluded children with neurological or genetic comorbidities. In the control group, we excluded children with abnormal m-CHAT or abnormal psycho-emotional development.

The Sensory Profile for Toddlers 2, translated to Arabic, was used to describe sensory abnormalities and was filled during clinical sessions with parents

Results:  

All the children with ASD had abnormalities in at least one sensory domain (p<0.001). The most significant differences in T-scores between the two groups were noted in general score, oral and tactile sections (p<0.001 for the three section) then in auditory sections (p=0.013), and movement (p=0.026); all more problematic in ASD group. No difference was found for vision (p=0.724).

More than 62% of children with ASD had more sensitivity/sensor patterns (+1 to +2 SD) versus 7%  in the typically developing group. More than 80% of the children with ASD had less seeking/seeker patterns (between -1 and -2SD) against only 35% of the typical developed children. Approximately 62% of children with ASD were more bystander versus 5% in the control group. There was no difference in the quadrant of avoiding/avoider.

We noted a correlation between the severity of ASD rated on the CARS and the presence of abnormalities on the sensory profile (p<0.001).

Conclusions:  With the exception of visual processing, sensory domains were clearly different and impaired in ASD group. Underlying neuronal processing abnormalities need to be clarified.