Postural Control Relates to Accuracy of Eye Movement in Autism Spectrum Disorder and Developmental Coordination Disorder

Background:  

Autism Spectrum Disorder (ASD) and Developmental Coordination Disorder (DCD) share similar motor features, including difficulty maintaining postural stability and coordinating body movement. However, the specific overlap in symptoms between these two disorders remains unclear. Further, while there are known differences in visual information processing in ASD, this research question remains unanswered in DCD.  Visuomotor integration – the use of visual information to guide motor behavior – may have a different impact on postural stability in ASD vs. DCD depending upon the influence of visual information processing. 

Objectives:  

To identify differences in visuomotor integration between individuals with ASD and DCD during tasks requiring the use of eye movement and visual information processing to maintain postural control.

Methods:  

We conducted a preliminary investigation of visuomotor integration in 5 participants with ASD and 5 age-matched individuals with DCD. Data were collected from mobile eye-tracking, motion-capture, virtual reality, and force plate systems. Participants completed 30 seconds of quiet standing with eyes open and eyes closed as a baseline. They then completed two tasks in the virtual environment (Safe Zones, Disc Match) that required integration of visual information with motor plans. Participants controlled an object in the virtual space by shifting their Center of Pressure (CoP) or leaning to move a marker placed on the C7 vertebrae and the sacrum, in order to match the position of a static or moving target.

Results:  

Individuals with ASD differed from those with DCD in their movement profiles during the three tasks.  During quiet standing, individuals with DCD exhibited greater postural sway during both eyes open and eyes closed conditions. During the Disc Match task, both individuals with ASD and DCD struggled to match their CoP to the oscillating trajectory of a target, and their accuracy varied by frequency of oscillation. During the Safe Zones task, individuals with DCD had greater medial-lateral displacement in their C7 and sacral marker positions. 

Conclusions:

While DCD and ASD share similar functional movement symptoms, quantitative analysis of motor skills reveals key differences between the two disorders when tasks require integration of visual and motor information. Motor markers such as CoP may serve to differentiate between these two developmental disorders in a way that would inform intervention approaches. Preliminary analysis of the corresponding eye-tracking data supports the hypothesis that atypical eye saccadic and pursuit eye movements may influence the degree of difficulty that individuals with ASD, but not DCD, have with maintaining postural stability during tasks that require integration of visual information to plan and execute full-body movement.