Child Outcomes and Behavioral Predictors of Treatment Response for Pivotal Response Treatment

Background: Pivotal Response Treatment (PRT) is an evidence-based naturalistic behavioral intervention which is traditionally delivered via a parent training model. Support for its use in improving language abilities has historically come from single-case studies using primarily behavioral observation measures. There is a critical need for examination of outcomes from larger samples and from objective measures which can be more easily compared across trials and to normative developmental trajectories. Furthermore, identification of behavioral factors which predict treatment response will be essential for selecting the best treatment for an individual child.

Objectives: This presentation will review outcomes from a randomized controlled trial comparing a Delayed Treatment Group (DTG) to a PRT package treatment (PRT-P) which combines parent training with clinician-delivered in-home treatment. We hypothesize that the addition of clinician-delivered early intervention may help boost child language development while parents are learning the PRT techniques. Our aim is to highlight new data demonstrating how standardized measures of language and cognitive abilities can be used to assess and predict treatment response in clinical trials.

Methods: Participants include 48 children with ASD and significant language delay, ages 2-5 years. Children were randomly assigned to DTG or PRT-P, which involved weekly parent training and 10 hours per week of in-home therapist-delivered treatment for 3 months, followed by a less-intensive phase with 5 hours per week of in-home treatment and monthly parent training sessions. Dependent measures included Clinical Global Impression Improvement (CGI-I) ratings by trained raters blinded to treatment condition, as well as standardized parent questionnaires such as the MacArthur-Bates Communicative Development Inventories (CDI), as well as structured behavioral observations.

Results: Examination of changes with PRT-P reveal that children in the active group acquired greater vocabulary as evidenced by an average gain of 137 words between baseline (M=134 ± 113.5) and post treatment (M=271 ± 205) on the CDI, which was significantly greater than changes observed in the DTG (F=6.089; df(1:34); p=0.019). CGI-I ratings indicate that the PRT-P group is showing more improvement in communication compared to controls (X²(3, N=40)= 17.50; p=0.001). Specifically, 4 children were rated as very much improved (0 in DTG), 10 children rated as much improved (2 in DTG), 4 children rated as minimally improved (14 in DTG) and one child rated “no change” (5 in DTG). In addition, greater change between baseline and post-treatment on the CDI was correlated with baseline Mullen Early Learning Composite (R: 0.716; p=0.009) and with Mullen nonverbal skills (R: 0.555; p=0.049) suggesting that better performance on tests of early cognitive skills may predict response to PRT.

Conclusions: These data suggest that the PRT package approach shows promise for addressing communication deficits associated with ASD. Potential benefits and challenges of a combined parent training and clinician-delivered early intervention approach will be discussed, with a focus on factors which may predict an individual child’s response to treatment and aid clinicians in better personalizing care.