Imitation of Atypical Biological Kinematics in Autistic Adults Is Associated with Sensorimotor Integration
Objectives: Examine the contribution of sensorimotor integration processing during voluntary imitation in autism.
Methods: Autistic, and control, adults observed single point-light models moving horizontally on a monitor and imitated using a stylus on a digital graphics tablet. A control model contained typical biological kinematics and displayed a bell-shaped (peak velocity occurs at 44% of the movement trajectory) velocity profile. An experimental model contained atypical biological kinematics and displayed peak velocity that occurred earlier (18%) in the movement trajectory. In Experiment 1 (autistic, n = 15; control, n = 15) and 2 (autistic, n = 15; control, n = 15), the typical (30 trials) and atypical (30 trials) models were presented in a constant trial order, counterbalanced across participants. In Experiment 2, participants performed an additional incongruent (continuous circle drawing) visuomotor task in the inter-trial period.
Results: The discrete (time to peak velocity) and continuous (root mean square error) kinematic data in Experiment 1 indicated autistic adults significantly (ps < 0.05) adapted imitation by reducing error across the imitation trials. We showed no adaptation effect in Experiment 2 when autistic participants performed a secondary visuomotor interference task in the inter-trial period.
Conclusions: These data indicate functional voluntary imitation in autistic adults, and importantly that the reported deficits (DeMyer et al., 1972; Hayes et al., 2016) in voluntary imitation in autism may have been associated with an imitation context that prevented sensorimotor integration and adaptation across trials. The finding from the secondary task supports the suggestion that atypical imitation and motor learning in autism (Haswell et al., 2009) is associated with atypical sensorimotor integration.