(PS10-43) Using EMA to improve our understanding of Prolonged Exposure homework: A case series of individuals with PTSD

Abstract Text: Prolonged Exposure (PE) is a well-established treatment for Posttraumatic Stress Disorder (PTSD) that involves completing in-vivo and imaginal exposure exercises both within treatment sessions and during homework between sessions. Although exposure homework is a crucial component of PE, we have relatively little insight into the number of exposures patients complete, the context in which they complete them (e.g., type and timing), and the distress they experience during the exposures. Ecological momentary assessment (EMA) surveys may aid in accurate, real-time measurement of homework details, improving our understanding of exposures outside of a clinical setting. In this case series, we evaluate the acceptability of PE homework exposures using EMA surveys and illustrate the insight that can be gained from this methodological approach.

Seven individuals with PTSD completed Prolonged Exposure treatment, including between-session exposures. Participants used a smartphone application (TigerAware) to complete EMA surveys during each exposure. EMA surveys included items assessing exposure context, including time of day, type of exposure (imaginal vs. in-vivo), location of the exposure, and pre- and post-exposure activities. The surveys also assessed peak distress elicited during exposures using the Subjective Units of Distress Scale (SUDS). Finally, participants reported the acceptability of using the EMA platform on a scale from 0 (not at all acceptable) to 4 (extremely acceptable). We will examine total recorded exposures, and report contextual factors as proportions of these exposures.

Participants overall rated TigerAware as very acceptable (Median 3.5, M = 3.33). Participants completed a mean of 34.43 exposures (min = 19, max = 88). The type of exposure was balanced between imaginal (M = 53%, min = 33%, max = 80%) and in vivo (M = 46%, min = 20%, max = 67%). Exposures were primarily completed in the afternoon (38.6%) or evening (44%). Participants predominantly engaged in exposures at home (M = 83%, min = 21.1%, max = 100%). Time leading up to exposures was usually spent relaxing alone (M =47.3%; min = 14.3%, max = 89.8%) or working (M = 20.7%, min = 4.5%, max = 52.6%). Time after exposures was primarily spent relaxing alone (M =59.8%, min = 0%, max = 92%), spending time with friends or family (M =15.4%, min = 0%, max = 63.2%), or working (M =12.4%, min = 3.3%, max = 48%). The mean peak SUDS was 62.71 (min = 22, max = 100) during participants’ first exposure and 41.86 (min = 15, max = 65) during their final exposure.

Outcomes of the present study suggest that EMA is a valuable methodological tool for understanding the exposures that take place outside of PE treatment sessions. Participants were able to fully engage in EMA assessments during homework exposures and rated them as very acceptable. Through the EMA data, we observed a broad range of the number of exposures participants completed between sessions, as well as variability in their context and elicited distress. Further studies should use EMA to clarify which aspects of exposures (e.g., number completed, context variability, SUDS) impact clinical outcomes of PE therapy in order to bolster treatment efficacy.