Protocol for a Pilot Two-Arm Crossover Randomized Controlled Trial of the ACTIVE Intervention for Older Adults with and Without Mild Dementia and Their Care Partners.

Background: Older adults, including those with Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD), face barriers in maintaining regular physical activity, which increases their fall risk and reduces their quality of life. The Activity Tracking, Care Partner Co-Participation, Text Reminders, Instructional Education, Video-Guided Physical Rehabilitation, and Exercise trial aims to improve physical activity among older adults. This pilot study aims to assess the feasibility and preliminary efficacy of the ACTIVE intervention. Methods: ACTIVE is a multi-method, two-arm randomized, analyst-blinded crossover pilot trial with an embedded qualitative component. We will recruit 50 community-dwelling dyads (older adult-care partner, n = 100), with and without mild AD/ADRD, in a 1:1 ratio. Each dyad will be randomized to the intervention or control arm, stratified by AD/ADRD diagnosis. The intervention arm will receive activity tracking, motivational texts, walking exercises, educational videos, and video-guided physical rehabilitation sessions, while the control arm will receive only activity tracking. The intervention will run in two halves: a three-week intervention/control, a one-week crossover phase, and a three-week control/intervention phase. The quantitative outcome measures will include feasibility measures (recruitment, adoption, adherence, acceptability, fidelity, and retention), and measures of preliminary efficacy (activity metrics, fall risk and fear of falling, functional limitations, and quality of life). Qualitatively, we will assess participants' experiences, and facilitators and barriers to engagement in physical activity through semi-structured dyadic interviews and thematic analysis. Conclusions: This pilot study will generate data on the feasibility and preliminary efficacy of the ACTIVE trial. Findings will inform a full-scale implementation trial.