Usability of the Coach-Supported Dementia Prevention App ENHANCE (Tailored Intervention for Brain Health and Cognitive Enrichment) in Older Adults: 1-Week Mixed Methods Study.

Background: Multidomain dementia-prevention interventions delivered via apps have the potential to reach large populations. However, existing trials have tended to recruit more socioeconomically advantaged participants, raising concerns that the resulting interventions may be less usable for older adults from minority ethnic, lower educational, or lower socioeconomic backgrounds, who are at higher risk of dementia. The Tailored Intervention for Brain Health and Cognitive Enrichment (ENHANCE) app was designed to address this by prioritizing accessibility and engagement across diverse user groups. Objective: This study evaluated the usability and user experience of the ENHANCE prototype during a 1-week at-home supported-use test and explored factors influencing use and engagement among older adults. Methods: We purposively recruited adults aged 60-80 years without dementia for a 1-week mixed methods usability evaluation through community settings, including groups underrepresented in dementia-prevention trials. Participants had at least 1 of 10 prespecified dementia risk factors, attended a face-to-face onboarding session with a coach, used the app at home for 7 days with ongoing coach support, and completed a posttest interview and satisfaction survey. We analyzed quantitative data, including app usage metrics and survey responses descriptively, and used reflexive thematic analysis of qualitative data from onboarding sessions, posttest interviews, coaching calls, and in-app messages. Results: Ten participants participated in the study. The mean age was 68 (SD 6) years, and 7 were females. Participants represented a wide range of deprivation (Index of Multiple Deprivation deciles: mean 4, SD 2, range 1-8), with 6 from ethnic minority backgrounds. All met prespecified minimum-use targets (watching a module video, completing a check-in, and playing assigned games at least once). Many demonstrated additional voluntary engagement: 5 rewatched the risk factor video, 7 used the in-app messaging feature, and among the 5 participants with the hypertension module, blood pressure was logged on an average of 5 out of 7 days. Survey responses indicated high satisfaction, perceived usefulness, and ease of use; 9 participants intended to continue using the app and would recommend it to peers. Qualitative analysis identified engagement facilitators, including rewarding game design, familiar interfaces, appropriately challenging gameplay, consistent virtual rewards, trusted expert information combined with peer stories, and coach support. Barriers included unclear visual cues, insufficient accommodation of motor or sensory impairments, and visual discomfort in some games. Conclusions: Older adults found the ENHANCE prototype usable, acceptable, and engaging over 1 week. Human coaching, inclusive design, and integration of expert and peer narratives were highlighted as key engagement drivers. These findings support further feasibility testing to examine longer-term engagement and provide design insights for more inclusive digital health interventions.