Does Pivotal Response Training Moderate the Effect of Social Anxiety Symptoms on Student Outcomes?

Background: Variability in response to intervention is commonly reported in outcome studies for children with autism.  Differential responses to intervention may be associated with both the type of intervention delivered and differences in children’s clinical characteristics.  Recent investigations have found differences in outcome associated with intervention type and children’s characteristics. However, the moderating effects of treatment variables and children’s clinical characteristics on student outcomes have yet to be convincingly identified.

Objectives: to identify the moderating effects of treatment type and child characteristics on student outcomes for children with autism. Specifically, the study evaluated differences in outcome following one year of the Strategies for Teaching Based on Autism research (STAR) program, a behaviorally-based intervention package with three distinct components: discrete trial training (DT), Pivotal Response Training (PRT), and teaching in functional routines (FR).  A variety of child variables were examined, including age and baseline levels of cognition, language, and behavior.

Methods: Participants included 191 students with autism in 53 kindergarten-through-second-grade autism support classrooms in a large urban public school district that participated in an intervention study.  As part of this study, students received instruction using the STAR program.  Fidelity to each intervention component (DT, PRT, and FR) was measured monthly via direct observations, and was analyzed as a product of intervention intensity and intervention accuracy. Child measures were completed by teachers, parents and direct observation at the beginning and end of the school year, and included the Differential Abilities Scales, 2^nd Edition (DAS-II, the primary outcome measure); Aberrant Behavior Checklist; Adaptive Behavior Assessment System, 2^nd edition; Autism Diagnostic Observation Schedule; Child Symptom Inventory; PDD Behavior Inventory; and Social Responsiveness Scale. Linear regressions with random effects for classroom and student were used to evaluate the association between change in DAS-II GCA scores and 1) fidelity to each intervention component and 2) child characteristics (age, language ability, autism severity, social skills, adaptive behavior, co-occurring psychological symptoms, and restrictive and repetitive behavior. To estimate the potential moderating effect of different intervention components on the association between child characteristics and outcome, we introduced interaction terms (intervention fidelity x child characteristic) into the regression model.

Results: In main effects analyses pivotal response training was associated with improved student outcomes.  Higher levels of social anxiety symptoms, as measured by the CSI, were associated with poorer outcomes.  Analyses testing the interaction of whether fidelity to pivotal response training moderates the association between social anxiety symptoms and outcome are ongoing.   

Conclusions: The findings that PRT was associated with improved gains for children with autism, even when implemented at lower levels of fidelity, suggests PRT may be an effective intervention choice in under-resourced autism support settings. The finding that children with greater social anxiety were more likely to have poorer outcomes suggests the importance of identifying and treating social anxiety symptoms early.  These results suggest that addressing social impairment, through interventions like PRT that focus on increasing engagement and social motivation, may be a necessary precursor or adjunct to improving response to intervention.