Neurophysiological Correlates of Sensory-Based Phenotypes in ASD

Children with autism spectrum disorder frequently present with atypical behavioral responses to sensory stimuli, as well as differences in autonomic nervous system (ANS) and neuroendocrine activity. However, no one consistent pattern appears to explain these differences within this heterogeneous population. To conceptualize more homogenous ASD subgroups, sensory-based subtypes have been explored. One subtyping mechanism groups children by sensory responsivity pattern in addition to sensory domain. Differences in nervous system responsivity to sensory input within this sensory-based subtyping scheme have not yet been investigated. This exploratory study used ANS indices (respiratory sinus arrhythmia [RSA], skin conductance level) and neuroendocrine (salivary cortisol) response to examine patterns differentiating these subtypes. Significant differences in RSA were found during baseline, and during tactile, tone and movement stimuli (p < 0.05). Subtype membership was predicted by RSA changes during auditory stimulation and recovery periods (p < 0.05). Results confirm that children with an adaptive sensory responsivity subtype differ from those children with sensory processing dysfunction, however, physiological variables did not distinguish between children with different patterns of sensory processing dysfunction.