Intervention targeting development of socially synchronous engagement in toddlers with autism spectrum disorder: A randomized controlled trial

Background: Social and communication impairments are core deficits and prognostic indicators of autism. We evaluated the impact of supplementing a comprehensive intervention with a curriculum targeting socially synchronous behavior on social outcomes of toddlers with autism spectrum disorders (ASD). Methods: Fifty toddlers with ASD, ages 21 to 33 months, were randomized to one of two six-month interventions: Interpersonal Synchrony or Non-Interpersonal Synchrony. The interventions provided identical intensity (10 hours per week in classroom), student-to-teacher ratio, schedule, home-based parent training (1.5 hours per month), parent education (38 hours), and instructional strategies, except the Interpersonal Synchrony condition provided a supplementary curriculum targeting socially engaged imitation, joint attention, and affect sharing; measures of these were primary outcomes. Assessments were conducted pre-intervention, immediately post-intervention, and, to assess maintenance, at six-month follow-up. Random effects models were used to examine differences between groups over time. Secondary analyses examined gains in expressive language and nonverbal cognition, and time effects during the intervention and follow-up periods. Results: A significant treatment effect was found for socially engaged imitation (p =.02), with more than doubling (17% to 42%) of imitated acts paired with eye contact in the Interpersonal Synchrony group after the intervention. This skill was generalized to unfamiliar contexts and maintained through follow-up. Similar gains were observed for initiation of joint attention and shared positive affect, but between-group differences did not reach statistical significance. A significant time effect was found for all outcomes (p <.001); greatest change occurred during the intervention period, particularly in the Interpersonal Synchrony group. Conclusions: This is the first ASD randomized trial involving toddlers to identify an active ingredient for enhancing socially engaged imitation. Adding social engagement targets to intervention improves short-term outcome at no additional cost to the intervention. The social, language, and cognitive gains in our participants provide evidence for plasticity of these developmental systems in toddlers with ASD. = landa&rank = 3.