Sensorimotor Integration in Autism Spectrum Disorders: A Behavioural Meta-Analysis

Background: Sensorimotor skills are often reported as atypical in individuals with autism spectrum disorders (ASD). Daily motor behaviours as diverse as grasping an object or regulating walking gait require the integration of sensory information. While intact sensorimotor integration is essential to navigate our everyday world, little is known about how atypical sensorimotor skills in ASD may vary across development and with clinical symptom severity.

Objectives: The main objective of this study was to conduct a comprehensive quantitative meta-analysis of sensorimotor skills in ASD. The specific aims were: to assess the consistency of atypical gross and fine sensorimotor behaviors in ASD, to examine the relationship between sensorimotor skills and ASD symptom severity, and to examine the effect of age on sensorimotor skills in ASD.

Methods: An exhaustive search was conducted in Psycnet, PubMed, Web of Science and Cochrane Database to identify studies in ASD from 1980 to 2018 that involved quantitative evaluations of motor coordination, motor impairments, arm movement, gait, postural stability, visuomotor or auditory motor integration. A total of 232 studies were identified, reviewed and coded. The Comprehensive Meta-Analysis software 2.0 (Borenstein, Hedges, Higgins, & Rothstein, 2005) was used to calculate study effect sizes (Hedges’ g) and analyze overall effect size using random effects models. The I2 index was used to examine heterogeneity across studies (Higgins et al., 2003). Visual inspection of funnel plots and a trim-and-fill procedure were used to assess the presence of publication bias (Duval & Tweedie, 2000).

Results: Results strongly support the presence of deficits in overall sensorimotor abilities in ASD (n=127, g=1.25, SE = 0.08; p< 0.001, CI=1.10-1.40). More specifically, these atypicalities extended to both fine motor abilities (n=76, g=1.16, SE = 0.1; p < 0.001, CI=0.96 -1.36) and gross motor abilities (n=67, g=1.31, SE= 0.11; p < 0.001, CI=1.10-1.52). However, clinical severity did not show a significant relationship with sensorimotor behaviors in available studies (n=19, r= -0.15; p= 0.21, CI=-0.37-0.08). Finally, a smaller analysis found an association between increasing age and improved sensorimotor behaviors in ASD (n=5, r=0.37; p< 0.001, CI=0.19-0.52). Heterogeneity of variance for all analyses was moderate to large (34-86%, except 0% for age), supporting the use of a random-effects approach. No evidence of publication bias was found.

Conclusions: These meta-analyses strongly support the presence of sensorimotor impairments that extend to both fine and gross motor skills in ASD. Deficits decrease with age, but do not appear to covary with social/communication symptom severity. This work provides a novel contribution to the field by quantitatively examining relationships between sensorimotor skills, development, and clinical symptom severity in ASD. The ultimate mission of this research is to set a theoretical groundwork for future sensorimotor-based interventions (e.g., music and dance) in ASD. By better understanding differences in sensorimotor deficits in ASD, it is hoped that interventions can be better designed to target these deficits.