The Effects, Usability, Satisfaction, Barriers, and Benefits of a Remote, Multidomain Website-based Intervention to Prevent Cognitive Decline in Older Adults

1. Introduction. In Mexico, dementia represents a significant public health problem due to its high and continually growing prevalence, especially in rural areas. This situation is linked to a high prevalence of factors associated with the development of dementia, a characteristic common to other middle- and low-income countries, where prevalence and incidence have not decreased as they have in high-income countries. Dementia has significant implications for individuals, their families, and healthcare systems. In older adults, dementia manifests as memory loss, alterations in thinking, behavioral changes, and difficulties in performing daily activities, which affect their autonomy and independence. The dependency associated with cognitive decline represents a significant economic burden for families, as approximately 80% of total costs are related to ongoing care, a burden that particularly affects informal caregivers. Furthermore, constant caregiving can have negative effects on caregivers' personal, professional, and emotional lives, with women bearing the greatest burden, providing nearly 70% of caregiving hours. In turn, dependency due to cognitive decline significantly increases the demand for, and costs of, emergency and hospitalization services. In various clinical trials, multicomponent interventions have been developed to reduce dementia-related risk factors through a multidisciplinary approach. However, the complexity of these programs has led to the integration of digital systems to facilitate their implementation and monitoring. Digital media offer an opportunity to improve the effectiveness of health interventions by reducing geographical barriers, expanding accessibility, and promoting ongoing engagement. However, in older adults, use of these systems is limited by cognitive, sensory, physical, and motivational obstacles associated with aging, as well as by health complications related to chronic illness. Cognitive difficulties-such as deterioration of working memory, prospective memory, and procedural memory, along with attention problems and slower processing speed-complicate understanding and efficient use of digital interfaces. Additionally, there are sensory limitations, especially visual ones, and physical restrictions related to motor skills that affect interaction with devices. These barriers can be intensified by motivational factors, particularly when the perceived usefulness of technology or its benefits is not evident, potentially leading to frustration and abandonment of the intervention. Therefore, in health interventions involving digital systems, it is crucial to assess their impact on cognitive function while taking usability and satisfaction into account. This ensures simple interfaces, immediate feedback, and smooth navigation, helping to identify barriers and benefits, with the aim of offering an effective remote preventive option. It is important to emphasize that quantitative instruments do not always accurately capture participants' expectations, perceived barriers and benefits, or potential strategies for improvement. In this context, the program "Mind and Movement for Cognitive Health (MeMo-Health-Cog)" was developed as a multicomponent intervention aimed at older adults without dementia in primary care. It combines aerobic physical activity and cognitive training using a grid mat, with the goal of promoting lifestyles that prevent cognitive decline and improve mental health. Preliminary results show improvements in overall cognitive function and decreased depression among older adults; studies still in the process of publication have also observed improvements in memory, executive function, and attention. The intervention has now been adapted to a web platform for remote delivery. In this pilot study, primary outcome variables will be measured, including the impact on subjective, objective, and specific cognitive function, along with adherence. Secondary variables, such as usability and satisfaction, will also be evaluated. Additionally, perceptions of acceptability will be examined, with an emphasis on the barriers and benefits of the remote intervention.
2. Overall objective. To evaluate the effect, usability, satisfaction, barriers, and preliminary benefits of the remote multicomponent intervention supported by a website, over three months, for the prevention of cognitive decline in older adults from Family Medicine Units No. 1 and 28, with follow-up at three months (t3).
3. Specific objectives. a) To evaluate the preliminary effect of the remote multicomponent intervention supported by a website on the primary outcome variables (subjective, objective, and specific cognitive function, and adherence) in older adults from Family Medicine Unit No. 28, with follow-up at three months (t3). b) To evaluate secondary variables - usability and satisfaction with the Mx MAUQ questionnaire - for the remote multicomponent intervention supported by a website in older adults from Family Medicine Unit No. 28, with follow-up at one month (t1) and three months (t3). c) To identify secondary qualitative variables (barriers and benefits) of the remote multicomponent intervention supported by a website in older adults from Family Medicine Unit No. 28 at the end of the intervention (t3).
4. Study design: The investigators will employ a mixed quantitative and qualitative design, with pre- and post-evaluations in the quantitative component and semi-structured interviews in the qualitative component (pilot study). This is a trial without a control group, as one is not required for a pilot study. The study population consists of IMSS beneficiaries affiliated with Family Medicine Units 1 and 28 in Mexico City, Mexico.
5. Hypotheses. a) It is expected that a multi-component remote intervention, supported by a website, over three months, will improve subjective, objective, and specific cognitive function in older adults, with effect sizes of 0.20 and 0.40, respectively, and an adherence rate of 70% at three months from the start of intervention (specific objective 1). b) It is expected that a multicomponent remote intervention, supported by a website, will achieve high satisfaction and usability among older adults at one month and at three months post-implementation (specific objective 2).
6. Sample size (quantitative part). Considering Viechtbauer's theoretical proposal for a pilot study, which recommends a minimum sample size of 59 participants, and accounting for a 20% dropout rate, the final sample size is 71 participants. For the qualitative part, 20 older adults will be interviewed:10 men and 10 women. Among the men, 5 will have high adherence to the intervention (≥70%), and 5 will have low adherence (\<70%); similarly, for the women, 5 with high adherence and 5 with low adherence will be included.
7. Website Development Process. The website's content was created over five rounds of sessions. Six experts contributed to defining the topics, with a coordinator acting as a liaison between the specialists and the systems engineers. An external reviewer from the development team also took part. All contributors had experience with cognitive decline in older adults. In the first round, experts identified the key dimensions. In the second, after establishing these dimensions, subdimensions were requested through further inquiry. The third round involved the experts developing the website's content on each topic. In the fourth round, each topic was presented for feedback, with the researchers providing comments and suggestions. The fifth round included a review by an external expert, whose feedback was recorded for subsequent revisions.
8. Implementation of the intervention. a) Prior training will last between three and four weeks, depending on learning difficulty, and will be conducted three days a week, with each session lasting one and a half hours. Each group will have up to 10 older adults. Training will be facilitated by a support team consisting of a nurse and a gerontologist, both previously trained. Participants and caregivers will also be provided with supplementary materials, including a grid mat for cognitive training, a watch to measure heart rate, a guide brochure for using the website, and the instructor's contact information to resolve any questions. b)The three-month intervention will provide remote support through daily morning Zoom sessions. During these sessions, the support instructor will reinforce safety by allowing access only to registered participants: all participants will be asked to identify themselves using their reference number and without a profile photo; anyone who joins with a photo will be placed in a waiting room until they provide their reference number. Zoom sessions may be suspended if a participant violates safety rules. When necessary, personalized feedback will be provided through WhatsApp messages, and participants may call or message the instructors with any questions. Participants must complete at least three routines per week to meet the recommendation of 150 minutes of physical activity per week for older adults.
9. Assessments will be conducted in person at baseline, one month, and three months at the National Medical Center Siglo XXI. These evaluations will be carried out by trained research personnel with expertise in gerontology, nursing, or general medicine, and each session will last approximately one and a half hours. After the study, the principal investigator will conduct the qualitative interviews. These interviews will be audio-recorded, and participants' identities will remain confidential and will be replaced by file numbers.
10. Adverse Events. The type (e.g., dizziness, pain, fatigue, muscle strains, falls, or injuries), number, and severity of adverse events will be recorded during exercise sessions and throughout the rest of the intervention period. Severity will be classified as follows: mild (does not affect daily activities); moderate (has a moderate effect on daily activities); and severe (requires hospitalization, results in persistent or significant disability, or constitutes a medically important or life-threatening condition). The study investigators will review all adverse events weekly. They will report all moderate and severe adverse events to the IMSS Ethics Committee and will halt the study if the data indicate any health risk to the older adult participants.
11. Motivation and Adherence Strategies. To improve adherence and reduce dropout among older adults in the program, participants who do not access the application for one week will receive individual reminder messages via WhatsApp encouraging use of the application and the program's physical exercise component. If an older adult still has not used the application after a further week of WhatsApp reminders, a phone call will be made to understand the reasons for non-use and to encourage continued participation. Additionally, participants may contact the study team by phone or private WhatsApp message with any questions, comments, or technical issues.
12. Covariates. The study covariates include participant demographic and clinical characteristics: age (years since birth); biological sex (male or female); formal educational attainment (years); current employment status (retired, employed, volunteer, unpaid worker, unemployed); marital status (married, widowed, divorced, single, other); current living situation (living alone, living with a spouse, living with children, or living without children); and self-reported comorbidities relevant to this study (e.g., vascular risk factors, orthopedic conditions, etc.).
13. Data Management and Confidentiality. Data entry will be conducted by trained staff. Data quality will be assessed before statistical analysis (eg, range checks for data values). Only members of the study team will have access to study information, and all information collected from participants will be kept private to ensure confidentiality. Consent forms bearing participant signatures will be stored in a locked location accessible only to the principal investigator (PI). All electronic data will be stored on the PI's laptop and on a password-protected backup hard drive. Any handwritten materials, such as field notes or other related research documents, will be stored and secured in a locked cabinet when not in use. Data will be erased and destroyed after 5 years, in accordance with IMSS Ethics and Research Committee guidelines. Only deidentified data will be used for reporting, publication, and dissemination of findings.
14. Statistical Analysis, 14.1. Quantitative Analysis. a) Descriptive analysis: continuous variables with a normal distribution will be reported as mean and standard deviation; variables without a normal distribution will be reported as median and interquartile range. b) Imputation of missing data: if the amount of missing data exceeds 20%, mixed linear models will be used for the main analysis. Missing data will be generated using at least five multiple-imputation methods and, to reflect more realistic scenarios, incomplete observations will also be included. Finally, a sensitivity analysis will be conducted to verify the stability of the results. c) Primary outcome: to assess how the intervention groups change over time, a repeated-measures ANOVA with two factors (time and group) will be conducted. Where significant, post hoc tests with adjustments for multiple comparisons (including covariates) will be used to identify specific differences between evaluation points and groups. Results will be reported as point estimates, 95% confidence intervals, and p-values, with p \< 0.05 indicating statistical significance. d) Secondary outcome: McNemar's test will be used to compare baseline proportions (t0) with those at 1 month (t1) and at 3 months (t3). If the numerical variables in the study do not follow a normal distribution, as confirmed by the Shapiro-Wilk test, the medians of the pre-test (baseline) and post-test (t1 and t3) scores will be compared using the Wilcoxon signed-rank test (paired data). A p-value of ≤ 0.05 will be considered statistically significant. Additionally, a multivariate analysis will be conducted using a generalized linear model to adjust for covariates, reporting 95% confidence intervals and p-values; p \< 0.05 will be considered statistically significant. Analysis will be performed using STATA 19 and SPSS 27.

14. 2 Qualitative Analysis. Interviews will be examined through inductive thematic analysis. Three researchers experienced in health services and systems research will independently review, code, and interpret the transcripts. They will then compare their decisions on emerging themes and response classifications to ensure consistency and reliability, resolving any disagreements through discussion and consensus. The researchers will first identify categories and themes from the data; these findings will later be interpreted within the framework of the Health Belief Model to explore perceptions of change and non-change. Interviews will follow a study guide, and participants' demographic variables-such as age, sex, education, and adherence-will be documented. Data management and organization will be handled with ATLAS.ti software.