Parent-Child Autonomic Synchrony During Vicarious Extinction Learning in Pediatric PTSD

Children learn about threat and safety in their environment in part from their caregivers, a process which may be disrupted in child psychopathology. This transmission may be seen through biological measures like peripheral nervous system outputs such as skin conductance (SCR). Fear learning deficits have been observed in fear-related disorders like PTSD but have received little study in terms of parent-child learning transmission. We used a vicarious fear extinction paradigm to examine whether biological synchrony (SCR and heart rate variability [HRV]) is a potential mechanism by which children learn safety cues from their parents. In this pilot study, 16 dyads (PTSD n=11, typically developing [TD] n=5) underwent a vicarious fear extinction paradigm. We used cross-recurrence quantification analysis (CRQA) to assess SCR and HRV synchrony between parent-child dyads. We then used a linear model to examine group differences between PTSD dyads and TD dyads. For SCR, a significant group difference (p=.037) indicated that TD dyads had higher SCR synchrony compared to PTSD dyads. For HRV, there were no group differences between PTSD and TD dyads (p=.325). In exploratory analyses, increased synchrony was related to an overall decreased autonomic reactivity during recall of fear (p=0.032). These results suggest that SCR synchrony, but not HRV, may be a potential mechanism that allows for fear and safety learning in youth. While these data are preliminary, they provide novel insights on how disruptions in vicarious extinction learning may contribute to fear-related disorders in youth. Furthermore, this study suggests novel approaches to studying dyadic trauma-focused therapies which critically rely on parental coaching to model appropriate fear responses to help their child to recover from trauma. Significance Statement This study provides evidence that biological synchrony is a potential mechanism through which youth learn threat and safety cues through their parents. We found that youth with PTSD have lower synchrony with their caregiver, and that synchrony was related to decreased overall autonomic reactivity, suggesting that synchrony may be indicative of overall safety learning. Further, decreased synchrony during fear extinction may potentially underlie the etiology of fear related disorders such as PTSD. These novel approaches may improve our understanding of dyadic trauma-focused therapies which critically rely on parental coaching to model appropriate fear responses to help their child to recover from trauma.