Do Physiological Measures of Arousal Align with Self-Reported Physical Sensations? Using a Novel Ambulatory Method to Understand Momentary Interoceptive Accuracy and PTSD Symptoms

Interoceptive accuracy, the valid perception of internal bodily states, is believed to be negatively impacted by trauma. Current theories suggest that interoceptive accuracy may worsen when experiencing some PTSD symptoms (e.g. dissociation) but strengthen when experiencing other PTSD symptoms (e.g. hyperarousal). The goal of this study was to test a novel ambulatory method for measuring interoceptive accuracy and assess whether PTSD symptoms (dissociation, hypervigilance, exaggerated startle, and flashbacks) impact interoception. Trauma-exposed adults (<i>N</i> = 80; <i>n</i> = 39 diagnosed with PTSD) completed 3 days of ecological momentary assessment (EMA; <i>n</i> = 2,158 observations) while wearing a mobile electrocardiogram collecting passive heart rate data (interbeat interval; IBI). Momentary (within-person) fluctuations in subjective physical sensations (racing heart, sweating, trouble catching breath, feeling shaky, feeling tense) and PTSD symptoms were assessed via EMA, whereas trait (between-person) differences in PTSD severity were measured with the Clinician Administered PTSD Scale-5 (CAPS-5). Multilevel models provided mixed support for hypotheses that momentary PTSD symptoms would predict moment-to-moment fluctuations in interoception. Flashbacks were associated with better interoceptive accuracy, but hyperarousal symptoms were not. Interoception was significantly better during moments with lower-than-average dissociation symptoms, but only among people with low CAPS-5 scores. A limitation of the study is that we used a single cardiac measure (IBI) to predict a mix of physical sensations, some of which are not cardiac-related. Future research should continue to narrow the subjective report of physical sensations and take objective assessment of interoception out of the laboratory and into the daily lives of trauma survivors.