Ambulatory physiological assessment of posttraumatic stress disorder: Integrating passive sensing with ecological momentary assessment to measure trauma reactivity.

Abstract

The development of wearable technology affords objective measurement of physiological states outside the laboratory. We used ambulatory physiological assessment to measure overall arousal and reactivity to trauma reminders, a hallmark symptom of posttraumatic stress disorder (PTSD). Ambulatory assessment improves upon laboratory-based tests by measuring actual trauma reminders as they occur in everyday life. In this study, we recruited a mixed-trauma sample of 80 participants (39 diagnosed with PTSD) who completed 3 days of ambulatory physiological assessment time-synced with self-reported ecological momentary assessments of trauma reminders and contextual factors. We assessed heart rate (interbeat interval [IBI]) as a nonspecific marker of overall physiological arousal, skin conductance and preejection period as markers of sympathetic activity, and respiratory sinus arrhythmia as a marker of parasympathetic activity. We found that individuals with and without PTSD did not significantly differ on average levels of any physiological marker. Among individuals diagnosed with PTSD, IBI was significantly lower, indicating higher arousal, when participants were reminded of their trauma. Trauma reminders were not significantly associated with respiratory sinus arrhythmia or preejection period. Skin conductance was significantly lower (indicating lower arousal) in the presence of trauma reminders, counter to predictions. For time-varying predictors, we found that trauma reminders were associated with weaker physiological responses, as indexed by IBI, when the reminders were perceived as controllable and when they were experienced in the presence of social support. Our findings support heart rate as an inexpensive and accessible marker that can elucidate the role of contextual factors affecting PTSD symptom expression. (PsycInfo Database Record (c) 2025 APA, all rights reserved).