Trajectory Of Respiratory Sinus Arrhythmia On Resting And Reactivity Measures Of Heart Period And Rsa Before And After Cbt In Children With Ptsd
Although it is suggested that a dysfunctional stress response system may be associated with posttraumatic stress disorder (PTSD) the neurobiological underpinnings are not well established, especially in children. There is also limited research on how treatment for PTSD may impact associated physiology. Respiratory sinus arrhythmia (RSA) is a reliable measure of parasympathetic stress reactivity, and both resting RSA and RSA reactivity are physiological indicators related to children’s emotion functioning and regulation. The present study examined if pretreatment resting RSA levels predicted RSA reactivity at pretreatment and the trajectory of resting RSA, RSA reactivity, resting heart period (HP) and HP reactivity after Cognitive Behavioral Therapy (CBT). Forty-nine children who experienced at least 1 traumatic event and presented with PTSD symptoms were assessed for psychological measures, RSA and HP at pretreatment, post treatment and a 3-month follow up. At pretreatment, lower resting RSA was associated with increased RSA withdrawal. Analysis with repeated measures mixed models indicated that lower resting pretreatment RSA and lower RSA withdrawal increased during CBT, and individuals with higher resting RSA and RSA withdrawal decreased during CBT, so that those at the extreme ends of higher and lower indices converged in the middle by the end of treatment. These data suggest an optimal moderate range for resting RSA and RSA reactivity. There were also significant gender differences on RSA reactivity after CBT. Lower pretreatment resting RSA predicted lower resting heart period (higher heart rate) across all time points but did not change with CBT. Pretreatment resting RSA did not predict HP reactivity. Post hoc analysis also revealed that PTSD symptoms were significantly reduced after CBT but this change was not associated with pretreatment resting RSA levels. Overall, these results suggest that children may change physiologically after CBT and the direction of the changes may depend on initial resting RSA levels.