Reduction in Restricted and Repetitive Behaviors Following Pivotal Response Treatment

Background: Restricted and Repetitive Behaviors (RRBs), one of the central symptoms of autism spectrum disorder (ASD), consist of diverse factors – such as repetitive sensory motor behaviors and insistence on sameness – that interfere with social interactions. Previous research on interventions for RRBs indicates resistance to pharmacological treatments and behavioral interventions (Harrop et al., 2015). Additionally, pharmacological interventions have notable side effects.

Pivotal Response Treatment (PRT) is a naturalistic behavioral treatment targeting social communication and social motivation. Preliminary work demonstrates PRT effectively reduces RRBs (Ventola et al., 2016).

Objectives: The present study evaluated changes in severity of RRBs in children with ASD following a 16-week trial of PRT.

Methods: The sample consisted of 45 children with ASD, 4-7 years-old. Thirty-five children received 16-weeks of PRT, consisting of 7 hours of weekly individual treatment and parental training. The sample was combined from an open-label trial of PRT and a RCT of PRT. Ten children were in a non-treatment control condition. RRBs measures were collected at baseline and endpoint using Repetitive Behavior Scales-Revised (RBS), Aberrant Behavior Checklist (ABC), and Social Responsiveness Scale (SRS). To evaluate changes in RRBs severity, paired-samples t-tests were conducted to compare baseline and endpoint scores on each measure.

Results: Independent samples t-test indicated no significant differences between the PRT and control group at baseline (RBS total: t(35)=-1.545, p=.131; ABC stereotypy: t(27)=.775, p=.444; SRS RRB: t(39)=-1.584, p=.121). Additionally, there were no significant IQ differences at baseline (Differential Abilities Scale, General Conceptual Abilities: t(42)=-.186, p=.854.)

Paired-samples t-tests revealed a significant overall reduction in RRBs severity following 16 weeks of PRT (RBS total: pre-PRT M=28.71, SD=19.637; post-PRT M=20.11, SD=12.029, t(27)=3.808, p<.001). This reduction is consistent across RBS subdomains: stereotyped (p=.002), self injurious (p=.014), compulsive (p=.020), ritualistic (p=.021), sameness (p=.005), and restricted (p=.009). Additionally, there was a significant decrease in SRS RRB-subdomain pre-PRT (M=14.80, SD=6.202) and post-PRT (M=12.57, SD=7.496; t(34)=2.557, p=.015), as well as in ABC stereotypy scores pre-PRT (M=11.97, SD=10.61) and post-PRT (M=8.58, SD=7.97; t(30)=2.814, p=.009).

Children in the control group did not exhibit significant reduction in RRBs severity during the 16-week period (RBS total: baseline M=41.22, SD=25.528; endpoint M=30.78, SD=15.189, t(8)=1.584, p=.152). RBS subdomain scores did not change significantly: stereotyped (p=.059), self injurious (p=.128), compulsive (p=.300), ritualistic (p=.272), sameness (p=.684), and restricted (p=.081). Similarly, there were no significant differences in ABC stereotypy at baseline (M=7.75, SD=5.377) and endpoint scores (M=4.75, SD=4.573; t(3)=1.009, p=.387), and SRS RRB at baseline (M=19, SD=4.382) and endpoint scores (M=18.17, SD=7.33; t(5)= .362, p=.732).

Conclusions: While PRT focuses on improving social communication skills, it has a secondary effect on RRBs severity. Results suggest a significant reduction in severity across a variety of RRBs following a 16-week PRT trial. This could possibly result from incorporating parent training and using circumscribed interests to motivate, and consequentially, increase reciprocal interactions. Future studies may examine follow-up data to assess the longevity of the effects of PRT on RRBs, as well as use diverse measures to evaluate RRB severity. Additionally, a larger sample is needed to measure generalization of this effect.