Abnormal White Matter Connectivity In Children With Autism Or Sensory Processing Disorder: Overlap And Divergence. (P6.012)

OBJECTIVE: To investigate the overlap and divergence of white matter microstructure between children with autism spectrum disorders(ASD), sensory processing disorders(SPD), and neurotypical controls. BACKGROUND: Over 90% of children with ASD demonstrate atypical sensory behaviors. In fact, hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment is included in the DSM-5 diagnostic criteria. However, there are children with SPD who do not meet an ASD diagnosis but do show atypical sensory behaviors to the same or greater degree as ASD children. We have reported abnormal white matter microstructure in children with SPD predominantly affecting posterior regions and correlating with atypical sensory behavior. In this study, we explore white matter connectivity in boys (8-11 years) with ASD(n=15), SPD(n=16), and controls(n=23). METHODS: We used probabilistic diffusion fiber tractography to define white matter tracts. Strength of tract connectivity was measured using mean fractional anisotropy. Group differences were determined with nonparametric permutation testing (p<0.05). RESULTS: Both SPD and ASD cohorts have decreased connectivity relative to controls in parieto- and temporo-occipital tracts subserving sensory perception and multisensory integration. In SPD, there is worse dysconnectivity than ASD in the occipito-inferior parietal tract of the dorsal visual stream. The SPD group alone shows decreased connectivity in the splenium of the corpus callosum and in the thalamo-prefrontal cortex pathway, whereas the ASD group alone shows lower connectivity in the lingual-orbitofrontal tract as well as the fusiform-amygdala and fusiform-hippocampus tracts essential to face processing. CONCLUSIONS: There is overlap of abnormal white matter connectivity between children with ASD and SPD in sensory processing pathways, but abnormal connectivity in tracts thought to subserve social and emotional processing is found only in the ASD group. These observations help clarify the roles of specific neural circuits among the widespread white matter microstructural abnormalities observed in children with ASD and SPD. Study Supported by: the Wallace Research Foundation, Gates Family Foundation, Simons Foundation, and the NIH. Disclosure: Dr. Marco has nothing to disclose. Dr. Chang has nothing to disclose. Dr. Owen has nothing to disclose. Dr. Desai has nothing to disclose. Dr. Harris has nothing to disclose. Dr. Hill has nothing to disclose. Dr. Arnette has nothing to disclose. Dr. Mukherjee has nothing to disclose.