Can Parent Report and Direct Assessment Measures Enhance Sensory over-Responsivity Phenotyping and Inform the Neural Underpinnings of Sensory Processing Symptoms?

Background: There is mounting evidence to suggest that sensory over-responsivity is common across children with neurodevelopmental disorders, including children with autism spectrum disorders (ASD) and sensory processing dysfunction (SPD). However, the standard methodology of determining these differences is with parent report questionnaires. There is no consensus on how to reliably measure sensory over-responsivity with a direct assessment tool by sensory domain. Reliable tools, both parent report and direct assessment, for determining the presence and nature of specific sensory dysfunction, such as over-responsivity, is a critical step for researchers and clinicians alike as we seek to understand the biologic underpinnings of sensory processing.

Objectives: This study has two main objectives, first to define a scoring methodology specific to tactile and auditory over-responsivity based on the Short Sensory Profile (SSP), a parent report questionnaire, and the Sensory Processing Scale Assessment (SPS-A), direct observation session, and then to analyze the inter-test agreement between these assessments. Second, using MRI Diffusion Tensor Imaging (DTI), we seek to determine whether children with auditory or tactile over-responsivity show uniquely decreased regions of white matter integrity.

Methods: Using a Research Domain Criteria (RDoC) approach this study included children with auditory and tactile over-responsivity from a mixed neurodevelopmental cohort (NDC), including children with ASD and SPD and children with no known neuro-sensory challenges. For our first aim, a large sample of typically developing children (TDC) children (n=128) was collected to establish cut-off scores for over-responsivity. Then all children (TDC, n=128 and NDC, n=21) were categorized as over-responsive in either the auditory or tactile domain if they deviated significantly from the expected mean. For the neuroimaging analysis, 39 children with both brain imaging and direct sensory assessment were included and grouped by sensory over-responsivity (yes/no) in either the auditory or tactile domain. Sensory-based group comparisons were then conducted comparing the white matter fractional anisotropy (FA) in 23 regions of interest (ROIs).

Results:  Cut-off scores for auditory and tactile over-responsivity were established. Using the direct observation, 57% of the NDC children had auditory over-responsivity and 33% had tactile over-responsivity. The Inter-test-agreement between SSP and SPS-A for auditory over-responsivity was 65% and tactile over-responsivity was 50%. Using neuroimaging DTI analysis, we found that children with auditory and tactile over-responsivity by direct assessment had 19 total tracts showing decreased white matter integrity relative to children without either auditory or tactile over-responsivity. Of these atypical tracts, 15 were uniquely associated with auditory over-responsivity and 2 were uniquely associated with tactile over-responsivity.

Conclusions: This study identified cut scores for auditory and tactile over-responsivity using the SSP parent report measure and SPS-A direct observation. This direct observation measure can be used in clinical and research settings. The SSP parent report and SPS-A direct observation ratings overlapped moderately for sensory related behaviors. Furthermore, based on our preliminary DTI results, we suggest that non-overlapping white matter tracts may contribute to the disruption of auditory or tactile processing leading to a domain specific over-responsive phenotype.