Atypical eye movements and postural control in Autism Spectrum Disorders (2016)

Purpose/Hypothesis: Research shows a link between eye movements, visual processing, and postural control, and evidence suggests these links are different in individuals with Autism Spectrum Disorder (ASD). The purpose of this study was to observe individuals with ASD and those with typical development (TD) in order to identify and characterize differences in how visual information is for postural control. Methods: Three participants in the ASD group (Age 16 + 4) and 3 in the TD group (age 14 + 4) completed the study, enrollment is ongoing. This study was conducted at the Fort Worth Museum of Science and History Research and Learning Center. All participants filled out a Data Collection Sheet to collect medical history, current medications, and demographic information relevant to the study. The experiment consisted of participant balance testing, including the Limits of Stability (LOS) and The Clinical Test for Sensory Integration (CTSIB), on a forceplate (BioSway, Biodex Corp) while wearing the ETG 2.0 (SensoMotoric Instruments) eyetracking system. Results: Adolescents with ASD had higher sway and stability indices than TD across all three conditions (eyes open, eyes closed, dome) of the CTSIB, as well as greater increases in sway and stability between the three conditions. During LOS testing, which required the participants to move their Center of Pressure to 9 targets displayed on the screen, the ASD group had lower control than the TD group in 5 of the 9 target positions. They also took a longer time to complete the task. Moreover, the ASD participants did not improve their performance across the 3 trials of the LOS. Pursuit eye movements and fixation of gaze on the targets during the LOS task were more variable in the ASD group compared to TD. The ASD group had more saccades, fixations, and blinks, possibly contributing to increased time required to complete the task. Conclusions: Research has identified differences in the eye movements of individuals with ASD and this might account for atypical postural stability. These preliminary data support the hypothesis that individuals with Autism have decreased postural control and accuracy and that these impairments may be linked to increased variability of pursuit eye movements. Further studies are necessary to investigate this atypical visuomotor integration and its possible role as a fundamental feature of ASD.