Did You See That Change? A Study of Dyspraxia, Eye Movement and Visual Perception in Autism

Background:  The literature on looking behavior of individuals with autism is extensive, as is the literature on spatial attention differences in autism.  Yet, we lack an understanding of the way in which lower level visual, motor and attentional mechanisms contribute to the biases in looking behavior often observed in individuals with autism.  Similarly, although there is evidence for deficits in overall motor coordination in autism, this work has not been extended to include eye movement. There are no attempts to compare motor control of eye movement with gross motor coordination and ability to perform skilled gestures (praxis). These functions are of particular developmental importance, as early sensory and motor abilities provide a scaffold for higher level skills such as social communication.  If eye movements are inaccurate or slow, social information is lost along with the opportunity to learn from that particular social situation.

Objectives:  Using a battery of tasks, we studied the interactions among eye movement, visual motor integration, visual perception and both fine and gross motor skills.  We examined associations between various aspects of the tasks to test whether atypical looking behavior observed in natural settings might be affected by fundamental visual motor deficits.

Methods:  We tested children with autism and typically developing age- and performance IQ-matched school-aged children who were recruited from an existing sample of children enrolled in studies of neural and cognitive development. Each child was evaluated using selected oral motor and limb apraxia subtests from the Florida Apraxia Screening Test. Visual-motor integration was evaluated using the standardized Beery-Buktenica Developmental Test of Visual-Motor Integration (VMI) and VMI supplemental tests in Visual Perception and Motor Coordination.  To examine eye movements and their role in natural visual perception, we used Gap-Overlap and Change Blindness paradigms.  Eye position samples were collected at 500Hz using the SR Research EyeLink 1000. Images for the Change Blindness task were naturalistic scenes that included social and non-social content that was balanced in terms of low-level salience, eccentricity and size.

Results:  In preliminary analyses, we found significant group differences in several tasks as well as correlations in performance across tasks. 

Children with autism performed more poorly on the VMI, Visual Perception and Motor Coordination tests, and a number of the Apraxia tasks. 

Compared to typically developing children, the children with autism were slower to initiate saccades to a target, and their saccades were less accurate. Children with autism also showed significantly greater variability in timing and accuracy of eye movements. Greater dyspraxia, poorer motor coordination and visual-motor integration were significantly associated with reduced control of eye movement.  These findings are consistent with a model in which dyspraxia is an underlying cause of the eye movement deficits seen in children with ASD.

Conclusions:  Oculomotor dyspraxia may explain some of the difficulties observed with eye contact and visual search often found in autistic individuals. These findings may contribute to the development of more appropriately directed clinical interventions.