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, a Stage I pilot trial indicated that smartphone-based memory aids (reminder apps) can be accepted and used by persons with mild cognitive impairment and mild dementia to improve both subjective and objective prospective memory performance. The investigators will now test for efficacy, durability, and generalizability of benefits across diverse samples in a Stage II randomized controlled trial. Some 200 participants with mild cognitive impairment or mild dementia will be recruited, half of whom will be from digitally-disadvantaged backgrounds (low socioeconomic status, rural, or historically underrepresented groups). 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 patient-selected and experimenter-assigned prospective memory assessments and receive booster training sessions to promote self-efficacy with the intervention/control system. Durability of effects will be assessed at 3-month and 6-month follow-up sessions. As a secondary aim, study partners will be simultaneously enrolled 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, the investigators will identify barriers and facilitators to smartphone interventions in digitally-disadvantaged individuals who have historically been underrepresented in technology and dementia research.

Inclusion Criteria:

• Demonstrate capacity to consent via structured interview that involves reviewing core study features and probing for understanding of potential benefits/consequences of participating, and understanding that one can withdraw consent at any point, or availability to obtain surrogate consent.
• Clinical features consistent with a diagnosis of MCI or dementia. For clinic-referred participants, available records will be reviewed to ensure the clinical diagnosis meets published diagnostic guidelines. If there is not sufficient documentation for diagnostic purposes, then semi-structured clinical interview and cognitive screening (see below) will be reviewed by clinical staff.
• Cognitive status for inclusion will be assessed by Montreal Cognitive Assessment (MoCA) scores of 17-25 (or 12-18 for the telephone version if in-clinic assessment is not feasible). While some studies suggested that these ranges are appropriate across diverse groups, recent work indicates that adjustment of 1-2 points for different demographics improves instrument sensitivity in disadvantaged groups. The latter approach will be taken.
• Functional status will be assessed via semi-structured interview with the Global Deterioration Scale (GDS), with stage 3 or 4 indicating independence in basic self-maintenance activities.
• Adequate sensory and motor abilities to utilize a smartphone with accommodation.
• Availability of a co-participant who sees the participant at least once a month.

Co-Participant Inclusion Criteria:

• The co-participant will need to be over the age of 18, consent to participation, and see the participant at least once per month.

Exclusion Criteria:

• History of serious mental illness including schizophrenia or bipolar disorder that is judged by the clinician to be the primary cause of cognitive decline.
• Indication of moderate or severe dementia based on clinical documentation, MoCA score, and/or collateral/informant activities of daily living measure during the screening process (GDS score ≥5).
• Language difficulties significant enough to interfere with the screening procedures.
• Uncorrected hearing loss, vision loss, or motor dysfunction significant enough to interfere with training.
• No study partner.
• At the current time, individuals who do not identify as conversational in English will be excluded from participation.

Co-Participant Exclusion Criteria:

• Sees participant less than once per month.
• At the current time, individuals who do not identify as conversational in English will be excluded from participation.

The investigators will use the repository provided by the Global Alzheimer's Association Interactive Network (GAAIN), depositing data within 9 months of publication.

Deposit data within 9 months of publication.

Open sharing.