Social Responsiveness Gains and Predictors of Outcome Associated with Social Pivotal Response Treatment for Toddlers with ASD: Results of an Ongoing RCT

Background:  During the early years of life, the ability to orient one’s attention to social cues of others, particularly parents, is imperative to development and social learning. Toddlers with autism spectrum disorder (ASD) demonstrate significant vulnerabilities in early engagement skills, such as social orienting and joint attention behaviors, which are found to be significant predictors of later language ability (Dawson et al., 2004). Specifically, known decreased sensitivity to visual and auditory social stimuli in their environment may lead to long-term negative effects on social, emotional, and language development (Dawson et al., 2002; McPartland et al., 2011). Early interventions that integrate social elements into reinforcement paradigms can dramatically improve collateral levels of interpersonal engagement (Vernon et al, 2012). This current investigation examined child responsiveness to parent engagement bids and its predictability of expressive language gains as a result of Pivotal Response Treatment.

Objectives:  This investigation focused on evaluating toddler social responsiveness to parent social bids in naturalistic play probes. Additionally, the study investigated whether pre-intervention levels of engagement could both (1) function as an accurate outcome predictor of expressive language abilities and (2) be improved in a PRT paradigm that emphasized engaging social exchanges.

Methods:  Participants were 19 toddlers (18-48 months) with ASD enrolled in an ongoing randomized controlled trial. Participants were age-matched and randomly assigned to a treatment (6 months of PRT focusing exclusively on social routines and reinforcers) or waitlist condition. At pre and post, all participants engaged in a five-minute structured laboratory observation (SLO) with their parent, in which parents were instructed to play with their child using a standardized set of toys. SLOs were coded for parent social play bids and the quality and frequency of child’s social responses. Additionally, videos were transcribed as a naturalistic measure of expressive language abilities. A repeated measures analysis of variance was conducted to assess for child engagement and language skills between groups before and after intervention.

Results:  When examining gains in global social responsiveness (verbal and nonverbal responses) to parent bids, results indicated a medium effect (ηp2=.06, d=.78) in the treatment condition compared to waitlist controls. Specifically for verbal social responsiveness, treatment participants exhibited improvements indicative of a large effect (ηp2 =.18, d=1.13) not observed in the waitlist condition. We can conclude that participation in a social PRT paradigm was associated with significant increases in social responsiveness and verbal engagement in response to parent social bids in naturalistic situations. Level of social responsiveness to parent bids at pre-intervention was correlated with several post-intervention language variables: number of total words (r²=.59, p=.03), number of novel words (r²=.67, p=.01), and average length of utterance (r²=.78, p=.002). While responsiveness to parent bids only required participants to engage nonverbally, pre-existing levels of engagement were significantly associated with resulting expressive language abilities following intervention.

Conclusions:  Low levels of engagement with parents are malleable to change as a result of social engagement intervention. Upon further exploration, this nonverbal naturalistic assessment may prove effective for predicting responsiveness to early intervention for minimally verbal children with ASD.