Child Behavioral Outcomes from a Randomized Controlled Trial of 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 objective outcome measures from larger samples. Furthermore, identification of behavioral factors which are associated with treatment response will be essential for individualizing treatment.

Objectives: This presentation will review behavioral 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. Our aim is to highlight new data demonstrating how objective measures of social communication 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 (M=46.3 ± 13 months). 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 ratings by trained raters blinded to treatment condition including functional verbal utterances [ICC (2,1) = 0.827] and parent fidelity of implementation [ICC (2,1) = 0.893] from Structured Laboratory Observation (SLO), Clinical Global Impression Improvement (CGI-I), as well as standardized parent questionnaires. Children in both groups continued stable community treatments during the trial (average of 9 hours/week in-home Applied Behavior Analysis).

Results: Examination of changes with PRT-P reveal that children in the active group demonstrated greater improvement between baseline (M=49.52 ± 32.1) and week 24 (M=70.57 ± 29.6) in frequency of functional utterances during the SLO compared to controls (BL: M=52.84 ± 24.6; Wk 24: M=54.16 ± 29.52; F(1,38)=4.517 p=0.040). Eighty-three percent of parents receiving PRT-P training met PRT fidelity of implementation criteria (80% fidelity) at week 24. Change in Total Utterances was significantly correlated with Parent Fidelity of PRT Implementation (r=.407, p=0.005). CGI-I ratings indicate that the PRT-P group showed 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 (12 in DTG) and one child rated “no change” (5 in DTG). Stronger baseline social communication skill on SRS-2 was associated with greater improvement in total utterances by week 24 (r=-0.387, p=0.007).

Conclusions: These data suggest that the PRT package approach was effective in increasing functional communication skills and the majority of parents were able to learn PRT during the trial. Child treatment response was associated with parent fidelity and baseline social communication skill. Benefits and challenges of a combined parent training and clinician-delivered early intervention approach will be discussed, with a focus on factors which can predict an individual child’s response to treatment and aid clinicians in personalizing care.