Abstract: Alzheimer’s disease and related dementias lead to marked declines in daily functioning, independence, and quality of life. One of the earliest cognitive changes in these conditions is impairment in prospective memory, or the ability to remember future intentions such as taking medications at a given time. Prior intervention studies that targeted prospective memory used mnemonic strategies or cognitive training, but these approaches resulted in modest gains in clinical populations. By contrast, our Stage I pilot trial indicated that smartphone-based memory aids (reminder apps) can be used by persons with mild cognitive impairment and mild dementia to improve both subjective and objective prospective memory performance. Having established feasibility and acceptability in the Stage I pilot study, we will now test for efficacy, durability, and generalizability of benefits across diverse samples in a Stage II randomized controlled trial. We will recruit 200 participants with mild cognitive impairment or mild dementia, half of whom will be from digitally-disadvantaged backgrounds (low socioeconomic status, rural, or historically underrepresented groups). These populations are well- captured by our clinical catchment areas. Participants will complete baseline assessments and then be randomly assigned to a smartphone reminder app intervention or an active control condition that uses a paper- based memory support system. Across a 4-week intervention period, participants will complete both patient- selected and experimenter-assigned prospective memory assessments and receive booster training sessions to promote self-efficacy with the intervention/control system. We will assess durability of effects at 3-month and 6-month follow-up sessions. It is unknown whether smartphone-based or paper-based approaches will be better at supporting prospective memory across 6 months in older adults with cognitive impairment and digital disadvantages. However, based on pilot data, we anticipate that the reminder app will be especially beneficial to prospective memory because it provides automated reminders, allows care partners to “push” reminders and events, and it includes daily alerts to use the app. As a secondary aim, we will simultaneously enroll family or friend study partners to collect informant ratings, track how much study partners assist the participants, and determine whether improving prospective memory in patients improves quality of life in study partners (e.g., by reducing the double to-do list burden of remembering for themselves and for care recipients). As a third aim, we will integrate quantitative and qualitative data to identify barriers and facilitators to smartphone interventions in digitally-disadvantaged individuals who have historically been underrepresented in technology and dementia research. This research will advance understanding of technology usage in older adults, inform whether smartphone-based reminder apps are effective and d...