Use and effect of web-based embodied conversational agents for improving eating behavior and decreasing loneliness among community-dwelling older adults: A randomized controlled trial (Preprint)

BACKGROUND Embodied conversational agents (ECAs) have been proposed as a promising interaction modality for the delivery of programs focused on promoting lifestyle changes. However, it is not understood which factors influence use of an ECA and their health effects. OBJECTIVE We aim to (1) identify whether ECAs can persuade community-dwelling older adults to change their dietary behavior and whether ECAs use can decrease loneliness, (2) test these pathways to effects, and (3) understand the use of an ECA. METHODS The web-based eHealth app PACO is a fully automated 8-week intervention in which 2 ECAs engage older adults in dialogue to motivate them to change their dietary behavior and decrease their loneliness. PACO was developed via a human-centered and stakeholder-inclusive design approach and incorporates Self-determination Theory and various behavior change techniques For this study, an unblinded web-based randomized controlled trial was conducted. Participants were recruited via social media, an online panel, flyers and advertorials. The intervention group received access to the PACO service for eight weeks. The waitlist group received PACO after waiting for four weeks. The primary outcomes, eating behavior and loneliness, were assessed via self-assesed online questionnaires at intake, waitlist, after 4 weeks, and after eight weeks. In addition, the primary outcome—use—was assessed via data logs. Secondary outcomes were measured at the same times, via questionnaires or an optional interview. RESULTS In total, 32 participants completed the intervention. We found a significant correlation between use in minutes on the one hand, and perceived usefulness (r = .39, P =.030) and enjoyment on the other (r = .38, P = .032). However, these did not predict use in the full regression model (F(2,29) = 1.98, P = .16, R2 = .12). Additionally, PACO use did not lead to improvements in eating behavior (χ2(2) = .34, = .85) or a decrease in loneliness (χ2(2) = .02, = .99). CONCLUSIONS Our study did not provide any concluding evidence about factors that are linked to the use or health effects of ECAs. Future service design could benefit from either creating a functional design catered towards the predominant stage of the targeted population, or by personalizing the service based on an intake in which the end-user’s stage is determined. CLINICALTRIAL ClinicalTrials.gov NCT04510883; https://clinicaltrials.gov/ct2/show/NCT04510883 INTERNATIONAL REGISTERED REPORT RR2-10.2196/22186