Background: Children with ASD often exhibit repetitive and stereotyped behaviors as well as difficulty performing motor actions. Difficulty in performing actions may stem from resistance to formulating new motor plans (persisting with previous motor plans even when new plans are needed for efficient movement). The aim of this study was to document flexibility of motor planning in individuals with ASD.Method: Five children with ASD and 5 neurotypical control children performed a grasp-and-place motor task. In successive trials, a wooden rod was placed in one of 24 different orientations -rotating either clockwise or counterclockwise around a circular template. A child grasped the rod and moved it. The position where the child switched from thumb-toward one end of the rod to the other in each direction was recorded.Results: Neurotypical children exhibited earlier grasp switches as well as a greater number of grasp switches as compared to children with ASD. Conclusion:We found preliminary evidence that, for children with ASD, changing a grasp was more costly than being uncomfortable.

The aim of this experiment was to document the role of multiple internal clock mechanisms and external sources of temporal feedback on reducing timing variability when two fingers tap instead of one (a phenomenon known as the bimanual advantage). Previous research documents a reduction in timed interval variability when two effectors time instead of one. In addition, interval variability decreases with multiple sources of feedback. To date, however, no research has explored the separate roles of feedback and internal timing on the bimanual advantage. We evaluated the bimanual advantage in a task that does not utilise an internal clock (circle drawing). Participants performed both unimanual and bimanual timing while tapping or drawing circles. Both tasks were performed with and without tactile feedback at the timing goal. We document reduced bimanual timing variability only for tasks that utilise internal clock-like timing (tapping). We also document reduced timing variability for timing with greater sensory feedback (tactile vs notactile feedback tapping). We conclude that internal clock mechanisms are necessary for bimanual advantage to occur, but that multiple sources of feedback can also serve to improve internal timing, which ties together current theories of bimanual advantage.

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