A pilot study on the gait kinematics in children with autism during perturbations of visual scene and support surface

Children with Autism Spectrum Disorder (ASD) have been widely reported to exhibit motor impairment. Previous studies of gait in children with ASD using an over-ground walking task suggest the walking kinematics and kinetics in children with ASD are atypical when compared to typically developing children (TDC). Considering walking in real life is often perturbed by sensory stimuli and that atypical sensory processing has been found in children with ASD, walking under sensory perturbations seems to be a reasonable approach for detecting possible walking abnormalities in individuals on the spectrum. The present study employed a gait perturbation protocol to evaluate the gait kinematics of children with ASD under a visually and proprioceptively challenging environments. We aimed to test whether children with ASD and TDC were similarly responsive to visual and treadmill perturbations (VP and TP). The second aim was to investigate how children with ASD and TDC recovered from VP and TP. Lastly, we intended to determine whether there were group differences in using the visual reference as a stabilizer of gait during a TP. Two children with ASD (8 and 11 years of age) and two TDC (ages 8 and 7 years) walked in the V-gait system (Motekforce Link, Amsterdam, Netherlands). When walking under VP, all four participants showed an increase in step width, and decrease in step time. One child with ASD exhibited greater magnitude of changes in gait kinematics under VP than other three participants. Both children with ASD exhibited a greater increase in step width variability compared to TDC. Under TP, all four participants applied shorter and faster steps. While one child with ASD showed decreased step width, the step width of other three participants during TP were increased. When VP/TP was over, all participants exhibited a tendency to recover their gait kinematics and stability to the opposite direction of the effects of VP/TP. All but one child with ASD recovered their gait kinematics when the visual cues turned on. These findings point to children with ASD seeming to exhibit similar but exaggerated gait responses to VP and TP when compared to TDC. Some children with ASD show deficits in using the visual information to stabilize gait. Thus, the visual motor coordination might be impaired in children with ASD. Future studies using similar perturbation protocol but with bigger sample size are needed.