A Pilot Investigation of the Relationship Between Parasympathetic Arousal, Stress, and Social Functioning in Youth with ASD before and after a Peer-Mediated, Theatre-Based Intervention

Background: Many individuals with autism spectrum disorder (ASD) experience significant physiological arousal and stress during social interaction. Dysregulation of the autonomic nervous system (ANS) has also been reported in ASD. Respiratory sinus arrhythmia (RSA) is an indicator of parasympathetic regulation and theorized as a marker of behavioral flexibility. Parasympathetic dysregulation in ASD may be associated with impaired social functioning, but a peer-mediated theatre intervention might help alleviate this altered ANS arousal during play.

Objectives: To investigate associations between RSA, stress, and social functioning before and after a theatre intervention. RSA was hypothesized to correlate with stress, social symptoms, and amount of cooperative play. Further, differences in RSA were expected following the 10-week intervention.

Methods:  The pilot investigation consisted of two preliminary studies. Study 1 included 21 children with ASD, ages 8 to 16. Children participated in the Peer Interaction Paradigm (PIP), a 20-minute playground interaction consisting of four 5-min. periods of independent (T1, T3) and cooperative play (T2, T4). RSA was collected at baseline and throughout the interaction. Parents reported stress, social functioning, and internalizing symptoms via the Stress Survey Schedule (SSS), Social Responsiveness Scale (SRS), and Child Behavior Checklist (CBCL). Pilot Study 2 assessed changes in RSA following a 10-week theatre intervention, with participants randomly assigned to the experimental group (n=12) or wait list control (n=9). Statistical analyses included ANCOVA for group differences and Pearson correlations for associations. Baseline RSA was subtracted from RSA during play to create difference scores representing RSA suppression, with more negative scores indicative of greater suppression.

Results: In Study 1, RSA during cooperative play T4 was negatively associated with total stress at trend (r=-.42, p=0.06) and significantly negatively correlated with the Changes domain of the SSS (r=-.51, p=0.02). Regarding ANS arousal and play, self-play during T2 was negatively associated at trend-level with RSA suppression (r=-.42, p=0.06), such that more self-play was correlated with a larger decrease in RSA. Amount of self-play at T2 positively correlated with social problems (r=.47, p=0.04) and internalizing symptoms (r=.51, p=0.02) on the CBCL and SRS total T-score (r=.44, p=0.05). In Study 2, no treatment effects were observed for baseline RSA or during the PIP (all p>0.05). RSA suppression was not associated with cooperative play (all p>0.05) either before or after the intervention.

Conclusions: Decrease in RSA during a stressor is considered a mobilization response. For youth with ASD, more stress, especially from changes throughout the day, was associated with greater decreases in RSA. This suggests children with higher stress perceive social interaction as more threat-inducing, indicated by greater suppression of the parasympathetic system. Those with lower RSA during play also engaged in more self-play, providing evidence that greater RSA suppression is associated with less social engagement. Increased self-play was related to social symptom severity, suggesting potentially important relationships between autonomic and social functioning that warrant further investigation. Though no treatment effects were observed, conclusions are limited due to the very small sample size and require future studies of a larger cohort to assess for significant changes following intervention.