(PS10-28) Physiological Arousal during Impact Statement Reading in Cognitive Processing Therapy for PTSD

Background: PTSD etiology and recovery is thought to involve the interaction of cognitive, psychological, and physiological dimensions. The study of the autonomic nervous system (ANS) is a way of exploring these dimensions, as well as patterns of emotion regulation and stress response that are implicated by PTSD. Physiological measures are commonly evaluated in laboratory-based settings but advances in wearable sensors now make monitoring during psychotherapy sessions more feasible. Cognitive Processing Therapy (CPT) for PTSD requires patients to write and read aloud an impact statement (IS), which includes details about a traumatic experience and the impact it had on the patients’ life. The IS is part of the initial assessment and treatment plan, and introduces skills that will be used to work through other relevant experiences. The IS is immersive, requiring the patient to handwrite the assignment, revise, and re-read it at the end of treatment. The IS provides a unique opportunity for assessing physiological arousal reactivity in a clinical setting due to its standard use in CPT, its potential to evoke emotional arousal, and the feasibility of using wearable sensors during therapy sessions. Investigation of ANS markers before and during the IS will help build a foundation for understanding individual treatment response and patterns in hyperarousal.

Methods: Data were collected from studies in which patients received up to 10 sessions of CPT. Electrocardiogram (ECG) recordings were collected before, during, and after sessions using a Biopac system. The present analysis investigates heart rate variability indices of mean heart period (HP), the average length of time between heart beats with lower values indicating higher arousal, and respiratory-sinus arrhythmia (RSA), a measure of parasympathetic activity. These metrics are easily collected with wearable sensors, and provide information on mobilization of the ANS and transitions into defensive states. Analyses of variance (ANOVA) & pairwise t-tests compared values during a neutral seated baseline before the therapy session, the beginning of the session, and the IS. Preliminary analysis includes 13 participants (Mage=39.38(24-58), 53.85% male). Data collection is ongoing and the analysis will be updated with a larger sample before the conference.

Results: All patients met full or subthreshold diagnostic criteria for PTSD. One-way repeated measures ANOVA did not show significant differences in RSA (F(2,24)=.059,p=.943,η2p=.005). However, there was a significant effect on HP (F(2,24)=5.39,p=.012,η2p=.31). Post-hoc Bonferroni-corrected paired t-tests revealed that mean HP was shorter (i.e., faster heart rate) during IS reading (M=780ms) compared to baseline (M=819ms; p=.034), with no other comparisons reaching significance.

Discussion: These results illustrate patient-level differences in physiological arousal as measured by HP, throughout a therapy session. Decreases in HP between the neutral baseline and IS reading indicate heightened arousal, potentially due to the emotional nature of the task. These findings support the use of wearable sensors for data collection during therapy, and will help understand changes in arousal during key moments in treatment.