Using Ecological Momentary Assessment (EMA) to Study Sex Events Among Very High-Risk Men Who Have Sex with Men (MSM).

MSM continue to represent the largest share of new HIV infections in the United States each year due to high infectivity associated with unprotected anal sex. Ecological momentary assessment (EMA) has the potential to provide a unique view of how high-risk sexual events occur in the real world and can impart detailed information about aspects of decision-making, antecedents, and consequences that accompany these events. EMA may also produce more accurate data on sexual behavior by assessing it soon after its occurrence. We conducted a study involving 12 high-risk MSM to explore the acceptability and feasibility of a 30 day, intensive EMA procedure. Results suggest this intensive assessment strategy was both acceptable and feasible to participants. All participants provided response rates to various assessments that approached or were in excess of their targets: 81.0 % of experience sampling assessments and 93.1 % of daily diary assessments were completed. However, comparing EMA reports with a Timeline Followback (TLFB) of the same 30 day period suggested that participants reported fewer sexual risk events on the TLFB compared to EMA, and reported a number of discrepancies about specific behaviors and partner characteristics across the two methods. Overall, results support the acceptability, feasibility, and utility of using EMA to understand sexual risk events among high-risk MSM. Findings also suggest that EMA and other intensive longitudinal assessment approaches could yield more accurate data about sex events.