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Introduction: Children with autism spectrum disorder (ASD) frequently display atypical motor functioning. This longitudinal study investigated atypical visuomotor integration in the development of action planning as one possible source.

Participants and Methods: Fourteen children with ASD and 17 typically developing (TD) controls participated three times over the ages 7 (T1) to 9 (T3) years. 3D kinematic registrations were made during performance of a manual sequential peg-rotation task with either visible or occluded goal-display condition before onset. Time, condition, and group differences were analyzed on onset-latency, part peak velocity in reach-to-grasp (PPV-RtG), remaining angle of peg-rotation at goal (p-RA), and fitting-duration.

Results: Time-point generated significant (p < 0.05) main effects for all variables. Stratifying by condition revealed shorter latency (both groups), higher PPV-RtG (visual-condition TD-group), lower p-RA (visual-condition TD-group; occluded-condition ASD-group), and shorter fitting-duration (visual-condition TD-group; occluded-condition both groups) with increasing age. Group generated significant main effects for fitting-duration. Stratifying by condition revealed longer fitting-durations (both conditions), and increased p-RA (occluded-condition at T1; visible-condition at T3) in the ASD-group. Condition generated significant main effects for all variables except fitting-duration. Stratifying by group revealed shorter latency (both groups), higher PPV-RtG (TD-group at T3), and reduced p-RA (TD-group at T3) in the visual-condition.

Conclusions: The results show different sensory-motor integration in the children with ASD, characterized by not benefitting from pre-existing visual information in action planning in accordance with their TD peers, particularly evident at 9 years. Our findings, based on longitudinal data, support suggestions that visuomotor integration underpinning action planning may operate differently in ASD.