Two-legged hopping in autism spectrum disorders

Abstract

Sensory processing deficits are common within autism spectrum disorders (ASD). Deficits have a heterogeneous dispersion across the spectrum and multimodal processing tasks are thought to magnify integration difficulties. Two-legged hopping in place in sync with an auditory cue (2.3, 3.0 Hz) was studied in a group of six individuals with expressive language impaired ASD (ELI-ASD) and an age-matched control group. Vertical ground reaction force data were collected and discrete Fourier transforms were utilized to determine dominant hopping cadence. Effective leg stiffness was computed through a mass-spring model representation. The ELI-ASD group were unsuccessful in matching their hopping cadence (2.21±0.30 hops·sec-1, 2.35±0.41 hops·sec-1) to either auditory cue with greater deviations at the 3.0 Hz cue In contrast, the control group was able to match hopping cadence (2.35±0.06 hops·sec-1, 3.02±0.10 hops·sec-1) to either cue via an adjustment of effective leg stiffness. The ELI-ASD group demonstrated a varied response with an interquartile range (IQR) in excess of 0.5 hops·sec-1 as compared to the control group with an IQR < 0.03 hops·sec-1 Several sensorimotor mechanisms could explain the inability of participants with ELI-ASD to modulate motor output to match an external auditory cue. These results suggest that a multimodal gross motor task can (1) discriminate performance among a group of individuals with severe autism, and (2) could be a useful quantitative tool for evaluating motor performance in individuals with ASD individuals. © 2013 Moran, Foley, Parker and Weiss.