OBJECTIVE: The purpose of this study was to investigate resting autonomic activity in adults who stutter (AWS) compared to adults who do not stutter (ANS) and the relationship this has on self-reports of social anxiety.
METHODS: Thirteen AWS and 15 ANS completed the Social Interaction Anxiety Scale (SIAS; Mattick & Clark, 1998) and Brief Fear of Negative Evaluation (BFNE; Leary, 1983). Following this, measures of skin conductance levels (i.e. index of sympathetic activity) and respiratory sinus arrhythmia (i.e. index of parasympathetic activity) were taken during a 5-minute resting, baseline period. Independent sample t tests were used to assess differences between groups on self-reports of anxiety (SIAS, BFNE) and resting autonomic levels (SCL, RSA). Separate multiple regression analyses were performed in order to assess the relationship between self-reports of anxiety and autonomic measures.
RESULTS: Results showed significantly higher mean SCL and lower mean RSA levels in the AWS compared to the ANS at resting, baseline. Regression analysis showed that self-reports from the SIAS had a significant effect on RSA levels for the AWS but not the ANS. No significant effects were found for BFNE on RSA. Nor was there a significant effect from SIAS or BFNE on SCL levels for either group.
CONCLUSIONS: Findings suggest that resting RSA levels may be a physiological marker for social anxiety levels in adults who stutter.

Individuals with autism spectrum disorder (ASD) often experience elevated stress during social interactions and may have difficulty forming and maintaining peer relationships. The autonomic nervous system (ANS) directs physiological changes in the body in response to a number of environmental stimuli, including social encounters. Evidence suggests the flexibility of the ANS response is an important driving factor in shaping social behavior. For youth with ASD, increased stress response and/or atypical ANS regulation to benign social encounters may therefore influence social behaviors, and, along with developmental and experiential factors, shape psychological outcomes.
The current study measured ANS response to a peer-based social interaction paradigm in 50 typically developing (TD) children and 50 children with ASD (ages 10-13). Respiratory sinus arrhythmia (RSA), a cardiac measure of parasympathetic influence on the heart, and pre-ejection period (PEP), a sympathetic indicator, were collected. Participants engaged in a friendly, face-to-face conversation with a novel, same-aged peer, and physiological data were collected continuously before and during the interaction. Participants also reported on state anxiety following the interaction, while parents reported on the child\'s social functioning and number of social difficulties.
Linear mixed models revealed that, while there were no diagnostic effects for RSA or PEP, older youth with ASD appeared to demonstrate a blunted parasympathetic (RSA) response. Further, increased severity of parent-reported social symptoms was associated with lower RSA. Youth with ASD reported more anxiety following the interaction; however, symptoms were not related to RSA or PEP response based on linear mixed modeling.
Physiological regulation, age, and social functioning likely influence stress responses to peer interactions for youth with ASD. Parasympathetic functioning, as opposed to sympathetic arousal, may be especially important in behavioral regulation, as older youth with ASD demonstrated atypical regulation and response to the social interaction paradigm. Future studies should help to further elucidate the developmental factors contributing to stress responses in ASD, the impact of physiological response on observable social behavior, and potential long-term consequences of chronic social stress in youth with ASD.

Callous-unemotional (CU) traits are implicated in the development of severe and persistent antisocial behavior, and appear to arise from distinct behavioral, temperament, physiological, and neural risk factors to other types of externalizing psychopathology. Although existing etiological models have attempted to characterize specific mechanisms underlying the emergence of CU traits, prior empirical work is plagued by a host of inconsistent results. This inconsistency is particularly apparent in research that has investigated variation in physiological functioning, arousal, and reactivity. In this review, we summarize and evaluate studies that have examined the role of parasympathetic nervous system (PNS) functioning in child psychopathology, including studies of CU traits. We argue that the inclusion of measures of PNS activity can significantly enhance our understanding of the etiology of CU traits, provide clarity to the inconsistent findings of prior studies, and advance mechanistically-targeted interventions and treatments. We conclude the review by providing foundational and testable hypotheses about the role that disrupted PNS functioning could play in multiple pathways to CU traits beginning in infancy and across development.

The field of psychodynamic psychotherapy would benefit from a comprehensive model that integrates its constructs with neurobiology. Research on the autonomic nervous system activity during the psychotherapeutic process is necessary because it is key in affective experiences and defensive behavior. The current case study reports physiological findings on heart rate dynamics in a patient suffering from panic disorder during two therapeutic sessions in which we used Davanloo\'s Intensive Short-term Dynamic Psychotherapy. We looked at various metrics of heart rate variability during the therapeutic process leading to breakthrough of unconscious feelings. The measurements included sympathetic and parasympathetic indices, vagal tone, and their responses. Our results suggest that the sympathetic system activates during defensive responses associated with anxiety and during the passage of unconscious-aggressive impulses. Following the experience of unconscious guilt, there is an increased vagal tone corresponding to the phase of reunification with the attachment figure. Findings are discussed integrating developmental neurobiology and clinical psychodynamics.