Early Social Interaction Project for Toddlers with Autism Spectrum Disorder: Identifying Active Ingredients of Treatment

Background: The priority of early detection of autism spectrum disorder (ASD) has led to the need for developmentally appropriate yet evidence-based intervention.  The Early Social Interaction Project (ESI) is a parent-implemented intervention for toddlers with ASD that teaches parents to embed transactional supports and strategies in everyday activities to achieve the intensity needed for toddlers with ASD in a cost-effective way.  A randomized controlled trial of ESI compared two 9-month conditions of varying intensity: 1) parent-implemented intervention (PII) offered in 3 individual weekly sessions for 6 months and then 2 weekly sessions for 3 months to teach parents how to embed supports in everyday activities to support the child’s active engagement 25 hours a week; and 2) an information, education and support group (IES) offered weekly for 9 months. Previous analyses (Wetherby et al., 2013) documented significant improvements on child outcome measures of social communication and language after 9 months in treatment, with children in PII demonstrating more significant gains on social communication (CSBS Communication; Vineland Socialization), language skills (Mullen Receptive Language, Vineland Communication), and adaptive behavior (Vineland Daily Living Skills) than children in IES.

Objectives: The aims of this study were: 1) to examine how changes in parents’ use of transactional supports mediate observed differences between children in PII and IES after 9 months in treatment; and 2) to examine the growth trajectories of parent’s use of transactional supports over 9 months of treatment.

Methods: Participating families (n= 82) were video-recorded during monthly home observations to measure the parent engaging the child in interaction during everyday activties for an hour.  Home observations at baseline, 3, 6, and 9 months of intervention were coded for parents’ use of 8 transactional supports using the Measure of Active Engagement and Transactional Support(MAETS; Wetherby, Morgan, & Holland, 2013).

Results: Aim 1: Mediation analyses were used to examine whether the amount of transactional supports used by parents would explain the differential growth in communication, language, and adaptive behavior by the PII and IES groups. Using bootstrapping to conduct mediation analyses, results indicate that the amount of transactional supports parents used mediated all observed treatment effects at 9 months. Aim 2: Results indicate that while parents in both PII and IES showed significant growth in their use of transactional supports, parents in PII showed faster growth, using more transactional supports earlier.  Growth curves of each support were compared by intervention group and follow-up regions of significance analyses were used to estimate the time point at which the PII and IES groups diverged in their use of supports. Parents in PII surpassed those in IES in their use of transactional supports by 90 days in intervention. 

Conclusions: Analyses indicated that the measure of transactional supports fully mediated the child intervention outcomes, highlighting the promising role that parents play in intervention delivery of for toddlers with ASD.  These findings suggest that features of PII may be critical to support parent’s acquisition and use of transactional supports within the first three months of treatment.