Dissociating proprioceptive deficits in Autism Spectrum Disorders: Intact acuity but impaired sensory integration in postural control.

Abstract

We investigated the presence of proprioceptive deficits in adults with Autism Spectrum Disorder (ASD), by assessing peripheral proprioceptive information (or proprioceptive acuity) as well as integration of proprioceptive information in the context of postural control. We hypothesized that proprioceptive acuity would be intact but that integration during a postural control task would be impaired. Sixteen adults with ASD and sixteen Neurotypical (NT) adults were screened using an IQ test and the adolescent-adult sensory profile. Proprioceptive acuity was assessed using an ankle Joint Position Sense (JPS) task and integration of proprioceptive information was assessed using a postural adaptation task. This task comprised standing upright, without vision in three phases: standing on a fixed surface for 2 minutes (baseline), followed by standing on a surface tilting in proportion to participants body sway, or support-surface sway reference for 3 minutes (adaptation) and finally standing on the restored fixed surface for 3 minutes (reintegration). Results showed no group differences in proprioceptive acuity and in the baseline phase, but greater postural sway during adaptation in individuals with ASD compared with NT controls. Specifically, group differences were not present in the first 30s of adaptation, but emerged after the second window suggesting a deficit in sensory integration of proprioception in adults with ASD. Our results suggest that peripheral proprioceptive information is intact in ASD but neural sensory integration of proprioception is impaired in this group.