Gait variability development in autistic individuals across childhood and adulthood

Atypical sensorimotor behaviors are prevalent in autism spectrum disorder (ASD), often emerging in infancy and persisting into early adulthood. Prior focus on qualitative metrics and developmentally specific motor skills has limited understanding of sensorimotor differences in ASD across the lifespan. The present study quantified gait kinematics in ASD across a wide age range, including analysis of 60 autistic individuals (ages 4-35 years) and 53 age-, sex-, and performance IQ-matched neurotypical (NT) controls. Autistic individuals differed from NT controls on seven gait variables reflecting within-subject variability of gait kinematics. These seven gait variability metrics were integrated into a canonical correlation analysis (CCA) with select demographic features (group, age, sex, IQ) to derive a composite gait variability score that accounts for the multicollinearity of gait variability and demographic metrics. The composite score revealed increased gait variability in autistic individuals relative to NT controls. Gait variability was negatively associated with age across the sample. Age-by-group interactions suggested that gait variability is more severely elevated in autistic individuals during adolescence and adulthood relative to childhood. Increased gait variability also was associated with more severe clinically rated ritualistic behaviors in autistic individuals. This study leverages a novel approach to define a multidimensional component score of gait variability in ASD from childhood to adulthood. Results indicate that gait variability is elevated in ASD, and that the severity of variability differences increases with age during adolescence and into adulthood. These findings suggest that autistic individuals show an attenuated development of sensorimotor feedback and motor planning processes that are involved in maintaining accuracy and stability of movements.