Behavioral interventions that incorporate naturalistic, developmental strategies have been shown to improve outcomes for young children who receive an autism spectrum disorder (ASD) diagnosis. Although there is broad consensus that children on the spectrum should begin supports as soon as possible, the empirical evidence for this is relatively limited and little is known about the optimal age to start autism-specific interventions. Our team conducted a randomized controlled trial (RCT) to test the effects of starting intervention at different ages, using the Early Social Interaction (ESI) model, a parent-implemented intervention for toddlers on the spectrum. Participants included 82 autistic toddlers and their caregiver(s) who received 9 months of Individual-ESI and 9 months of Group-ESI, with the timing/order of these two treatment conditions randomized. Thus, families received the more intensive and individualized Individual-ESI at either 18 or 27 months of age. Results revealed that children who received Individual-ESI earlier showed greater treatment gains than those who received this intervention later. Gains were demonstrated in several areas, which included the use and understanding of language, social use of communication skills, and self-help skills. Importantly, these findings were specific to the intensive and individualized parent coaching model compared to group-based treatment, allowing us to rule out the possibility that these timing effects were due to children getting older rather than the treatment itself. Our results suggest that even a narrow window of 18 versus 27 months may have an impact on outcomes and underscore the importance of screening and evaluation as young as possible.
Keywords: Early Social Interaction; autism; early intervention; parent coaching; toddlers.