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 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.

<p><strong>Purpose: </strong>The need for community-viable, evidence-based intervention strategies for toddlers with autism spectrum disorder (ASD) is a national priority. The purpose of this research forum article is to identify gaps in intervention research and needs in community practice for toddlers with ASD, incorporate published findings from a randomized controlled trial (RCT) of the Early Social Interaction (ESI) model (Wetherby et al., 2014) to illustrate community-based intervention, report new findings on child active engagement from the ESI RCT, and offer solutions to bridge the research-to-community practice gap.</p>

<p><strong>Method: </strong>Research findings were reviewed to identify gaps in the evidence base for toddlers with ASD. Published and new findings from the multisite ESI RCT compared the effects of two different ESI conditions for 82 toddlers with ASD to teach parents how to support active engagement in natural environments.</p>

<p><strong>Results: </strong>The RCT of the ESI model was the only parent-implemented intervention that reported differential treatment effects on standardized measures of child outcomes, including social communication, developmental level, and adaptive behavior. A new measure of active engagement in the natural environment was found to be sensitive to change in 3 months for young toddlers with ASD and to predict outcomes on the standardized measures of child outcomes. Strategies for utilizing the Autism Navigator collection of web-based courses and tools using extensive video footage for families and professional development are offered for scaling up in community settings to change developmental trajectories of toddlers with ASD.</p>

<p><strong>Conclusions: </strong>Current health care and education systems are challenged to provide intervention of adequate intensity for toddlers with ASD. The use of innovative technology can increase acceleration of access to evidence-based early intervention for toddlers with ASD that addresses health disparities, enables immediate response as soon as ASD is suspected, and rapidly bridges the research-to-practice gap.</p>