Clinical Correlates of Corollary Discharge Signaling in Children with Autism Spectrum Disorder

Background: Sensory and motor impairments are key features of autism spectrum disorder (ASD). An abnormality in the link between action and sensation may underpin these symptoms. Corollary discharge (CD) signals enable such a link between sensory and motor systems. CD signals are “copies” of motor signals sent to sensory brain regions at the same time the corresponding motor commands are sent to motor regions. They allow organisms to suppress sensory consequences of self-generated actions in order to enhance attention to and processing of external sensory input. We hypothesized that altered CD signaling in ASD contributes to heightened bodily awareness and hypo-responsiveness to external sensory input, resulting in sensory-seeking behaviors such as repetitive motor mannerisms.

Objectives: To test (1) whether CD signaling is disturbed in children with ASD, compared to typically developing (TD) children; and (2) whether CD signaling is related to sensory and motor symptoms in children with ASD.

Methods: Eighteen children with ASD and 15 TD children (matched on age, sex, and IQ) performed a task that measures the influence of CD on visual perception following a saccadic eye movement. Subjects are instructed to look first at a visual target. Upon saccade initiation, the target disappears and reappears at a horizontally displaced position. Subjects then indicate the direction of displacement. If CD is intact, subjects are able to make accurate perceptual judgements, despite variability in saccade landing site. If CD is disrupted, subjects instead use saccade landing site to inform perceptual judgements. Two measures of CD integrity are derived: (1) the slope, which measures individuals’ reliance on saccade landing sites when making perceptual judgments and (2) just noticeable difference (JND), which indicates individuals’ sensitivity to target displacement. Larger JND and smaller slope indicate reduced influence of CD. Sensory and motor symptoms were measured by the Restricted and Repetitive Behaviors subscale of the Autism Diagnostic Observation Schedule (ADOS-2), the Body Perception Questionnaire (BPQ), and the Beery VMI Developmental Test of Visual-Motor Integration.

Results: There were no significant group differences between ASD and TD children on either JND (t(31) = -.01, p = .99) or the slope (t(31) = -.06, p = .96). However, in the ASD group, smaller slope (i.e., reduced CD signaling) was correlated with more severe restricted and repetitive behaviors on the ADOS-2 (r_Spearman = -.73, p = .002). Moreover, smaller slope also was correlated with heightened interoceptive awareness on the BPQ (r_Spearman = -.52, p = .03). Larger JND (i.e., reduced CD signaling) and smaller slope were both correlated with poorer performance on the Beery Motor Coordination subtest (r_Spearman = -.56, p = .02; r_Spearman = .70, p = .001).

Conclusions: These results suggest that CD signaling may be underlying some of the core motor functioning and sensory processing symptoms in ASD, indicating a shared mechanism for internal preoccupation and repetitive motor symptoms. If such preliminary findings are replicated in a larger sample, this study could provide novel insight into underlying mechanisms of ASD and point toward potential intervention targets.