Intergenerational Behavioral Intervention to Enhance Physical Activity in Older Adults at Risk for Alzheimer's Disease

This is a four-week pilot randomized controlled trial of a behavioral intervention in older adults at risk for Alzheimer's disease. Older participants are a subgroup from the PREVENT-AD longitudinal cohort. We will test whether a four-week intergenerational social motivation using a technology-based platform (intervention group) enhances physical activity relative to a control group.

This study is a two-arm, single-site randomized controlled trial to test whether a four-week technology-based intergenerational social motivation intervention enhances physical activity in 60 cognitively unimpaired older adults with a first-degree history of Alzheimer's disease. These at-risk older adults will be recruited as a subgroup from a longitudinal cohort at McGill University, PREVENT-AD. At the outset, half of the participants will be randomized to the intergenerational social motivation condition (intervention group) and the other half will be randomized to the control group (1:1). A multimodal AD risk score based on older participants' already acquired AD biomarker, health and cognitive data will be used as strata for randomization to ensure equal assignment of high-risk participants to Intervention and control groups, using a permuted block method with random blocks.

The primary outcome is an increase in step count as measured by accelerometer. Secondary outcomes are an increase in total physical activity, mood, generativity, cognition, and loneliness. After an initial visit consisting of behavioral testing and structural and functional MRI, participants in the intervention group will be paired with younger adults (14 to 40 years) to form intergenerational dyads. Younger adults are either a family member of the older adult or a younger adult recruited from the community. Participants in the intervention group will receive personalized, positive daily messages over a four-week period via their device using the 'Our Family Garden' technology platform. These daily messages combine (1) pro-social goals (donation to charity after reaching exercise goals), (2) intergenerational social engagement, and (3) positive personalized messages from their younger study partners. This study will have 6 visits over a 2-month period in addition to the four-week intervention period (3 months total). Cognitive and behavioral data will be collected at each visit and physical activity data will be collected over the intervention period.

The primary endpoint is defined as the end of the initial period. Data collected are stored in one of three ways; (1) Physical activity monitoring data are extracted from their respective software packages and uploaded directly to a secure data storage environment at a high-performance computing facility. All pen-and-paper psychosocial and neuropsychological assessments are scored and entered in REDCap. Computerized psychosocial assessments are collected directly in REDCap and computerized neuropsychological assessments are entered in REDCap. TextMagic is used to distribute the daily intervention messages. Collected and anonymized survey data are stored on the web application behind an administrative login developed with Django, a high-level Python web framework. All data from REDCap will be exported to CSV files using the data de-identification feature for subsequent analysis with R and SPSS statistical analysis packages. After compiling all data across the 3 different data servers, data will be checked for completeness and correctness using frequency distributions (for missing data and out-of-range values). For the final dataset, the multiple imputations by chained equations (MICE) will be used to input missing values with 10 imputations.

Eligibility Criteria:
Main Participant Inclusion criteria:

Men and women \> 60 years Who are current participants of the PREVENT-AD Longitudinal Cohort at McGill University.

No contraindications to MRI Imaging. Normal cognition Not exercising more than 150 minutes of moderate-intensity exercise per week or sitting more than 8 hours per day AND responded "yes" to the question "Do you want to increase your physical activity?" Fluency in English or French Access to a computer or smartphone with internet Normal or corrected-to-normal vision based on the minimal 20/20 standard Ambulatory without significant increase in pain with walking or the assistance of walking devices

Main Participant Exclusion Criteria:

Primary care physician does not approve additional physical activity An inability to ambulate without the assistance of another person or severe pain

Any unstable medical condition:

* History of a psychiatric illness including schizophrenia or Attention Deficit Hyperactivity Disorder (ADHD). History of anxiety or depression accepted if stable on medication for at least 6 months
* Current treatment for cancer - except non-melanoma skin cancer
* Neurological condition (e.g., multiple sclerosis, Parkinson's disease, and stroke)
* Current alcohol or substance abuse
* Current treatment for congestive heart failure, angina, uncontrolled arrhythmia, Deep Venous Thrombosis (DVT) or other unstable cardiovascular condition
* Myocardial infarction, coronary artery bypass grafting, angioplasty or other cardiac event in the past six months.

Younger Adult Inclusion Criteria:

* Can be identified as child or grandchild of participant (biological or adopted), 14 years or older.
* Can be a young adult (18 years or older) who is not a relative of the main participant, in case a grandchild or child is not available.
* Stable on antidepressants for more than 6 months.
* In contact with the primary participant more than once per 12 months at baseline
* Lives anywhere in Canada if 18 years and older, or anywhere accessible by mail in Quebec if 14 years and older but younger than 18 years.
* Normal or corrected-to-normal vision based on the minimal 20/20 standard to complete the cognitive tasks
* Able to speak, read, and write English or French
* No diagnosis of neurological disease or unstable health condition

Study Partner Exclusion Criteria:

• Not in contact with the primary participant more than once per 12 months at baseline