The study uses a prospective, nonrandomized feasibility design to investigate the level of uptake of DemPower among couples where one partner has a diagnosis of dementia. The methodology facilitates an assessment of study processes to explore the criteria for a full trial.

The study will involve couples with one partner having a diagnosis of dementia and who live together at home. We will seek to recruit a wide and diverse couple population. This extends to any type of dementia, sexual orientation, age, profession, social, cultural, and religious contexts. Participants will be enrolled regardless of comorbidities experienced by a partner with dementia and the health status of a supporting partner. We will also include participants enrolled in other research studies. The wide diversity of participants is envisaged to study a better understanding of potential participants for a future full trial. This also provides opportunities to explore population needs, compare outcomes, and inform the areas that need further development. Specific inclusion and exclusion criteria are listed in Textbox 1.

As this is a feasibility study, no formal power calculation is needed. Instead, Lancaster et al [34] recommend including between 30 and 50 participants (in this study, couples) to estimate critical parameters (eg, recruitment rate; standard deviation of primary outcome) with necessary precision. This study does not aim to randomize participants, and therefore, there is no control group in this study. We will aim to recruit 50 couples across North West England and Sweden (Linköping and Norrköping). Figure 1 describes various stages of the study.

Living Life and Doing Things Together is a couple management guide delivered through the platform of an electronic application on a touchscreen device (Android tablet). The guide is aimed at enhancing the wellbeing as well as the relationship of couples where one partner has a diagnosis of dementia. The contents in this guide are based on couples with lived experience, available research, and practice evidence.

The objectives of the DemPower guide are (1) to help couples focus on the activities that they can do rather than what they cannot, (2) to reflect upon the strengths of their relationship, (3) help couple find ways to tackle daily activities together, and (4) to archive reflections, moments, and memories the way they would like them to be remembered.

The guide is structured under 4 primary themes and several sections within each theme, as illustrated in Figure 2. The themes and corresponding sections are introduced using storyboard techniques with a voiceover. Videos clips of couples sharing their experiences demonstrating particular situations follow storyboard illustrations. The guide makes suggestions for activities under each section. Examples of some suggested activities include games (stored on the device), links to useful information, taking pictures, writing reflections, and discussing emotions, needs and required changes to their home and their approach to daily life.

The app design facilitates various forms of user interfaces and provides users the control over font size, color, language, volume etc. The design also focuses on making the interface simple and easy to access. The interaction within the app is multimodal (voice, touch, text to speech). User-centered and participatory approaches inform the overall app design and concept.

The app and all the corresponding resources will be saved onto a portable device (tablet) prior to handing them over to the recruited couples (one tablet per couple). Researchers will provide a tutorial on how to use the device and the app. A detailed help video is inbuilt into the app. Researchers will provide a printed copy on how to use the device and the guide to all the participants. The participants may contact researchers at any time if they require technical support. The researchers will call the participants once a month to check their progress and arrange visits if required. We will recommend the participants to engage with two sections per week. They have the option to engage with a selection of sections or with the entire guide and in any order. Participants are expected to complete the guide within a period of 3 months from the date of device activation.

The goal of the study is to explore feasibility, acceptability, and usability of DemPower among couples where one partner has dementia. Using Bowen et al’s [35] suggested areas of focus for feasibility studies, Table 1 reports the approaches and measures used to assess the different aspects of the feasibility and acceptability of the DemPower intervention [35-37]. The structure in Table 1 helped to identify relevant outcomes, demonstrate how these address study objectives, and inform the choices of data collection procedures.

Two primary data sets will be generated from the study: evaluation and outcomes data. The study team designed a set of evaluation questionnaires to assess participants’ experiences with DemPower and the study processes (Multimedia Appendices 1-5). These questionnaires, DemPower, and chosen outcome measures will be tested with couples from a consultancy group for comprehension errors and bug fixing prior to the feasibility phase. The outcomes used to represent effectiveness include health-related aspects of quality of life, self-efficacy, interconnectedness, and mutuality on the part of both partners.

Table 2 presents the measures used to assess the potential effectiveness of the DemPower app and provide information for the design of any future randomized controlled trial (RCT), including sample size estimation.

An evaluation questionnaire will explore participants’ experiences with the guide, relevance of guide’s contents, usability of the app, perceived benefits, relevance of the guide in everyday living, applicability to various contexts, the volume of contents, and the time required to complete the guide (Multimedia Appendix 1). Responses to questions may vary from rating, multiple choices to descriptive forms.

At the end of each section, written instructions will be provided, guiding participants to use a particular set of questionnaires. Questionnaires are split across 4 themes presented in the guide (Multimedia Appendices 2-5). Researchers will follow up on participants’ progress with the questionnaires during regular telephonic conversations or home visits and offer support if required.

The following usage data will be stored on the tablet to measure how the app is used:

The outcome measures, questionnaires, and usage tracking data will form primary sources of data for this part of the study. All the questionnaires will be administered using an offline or a paper-based survey tool. The researcher will administer the outcome measures listed in Table 2 at baseline (prior to introducing the guide) and at the end point. Participants who choose to engage with only parts of the intervention will also be assessed at the start and at the time that they declare as completed or at the end of 3 months from the intervention initiation date. The details of participants’ progress, telephonic follow-ups, home visits, and variations in follow-up time frames will be recorded in the researchers’ logs. Researchers will support the person with dementia as he or she completes the outcome measures at baseline and at the end point during face-to-face meetings. Spouse or partner caregivers will be encouraged to complete the assessments on their own during the researcher’s visit.

The outcome relevant to the design process is to ascertain if a main study is feasible by classifying the study under one of the following categories: (1) Stop – main study not feasible; (2) Continue, but modify protocol – feasible with modifications; (3) Continue without modifications, but monitor closely – feasible with close monitoring, and (4) Continue without modifications – feasible as is.

The evaluation of the study process will be informed by Medical Research Council’s guidance on complex interventions [36], and principles and questions specific to feasibility designs discussed by Bowen et al [35] and Osmond and Cohen [46].

The process evaluation plays a key role in assessing the quality of study implementation, recruitment capability, attrition rate, data collection procedures, relevance of outcome measures and evaluation questionnaire, resource capability for implementing the study and acceptability of randomization. The study design does not allow for evaluating the randomization process; therefore, the acceptability of randomization will be explored with participants in the form of open-ended questions administered at the end of the study.

The data relevant to these areas will be obtained from researchers’ field notes, process evaluation questionnaires, recruitment and attrition data, contextual data associated with variations in outcomes, evaluating research team’s capabilities, researchers’ observations of suitability of outcomes, questionnaires, the burden on participants, and support required and will use results from the intervention segment to assess the relevance of chosen methodology.

All the data obtained from outcome measures and evaluation questionnaires will be entered into an Excel or Stata database for further statistical analysis. The data will be anonymized prior to being uploaded to a database. The qualitative or open-ended responses from evaluation questionnaires will be categorized and analyzed thematically. The data from Sweden will be transferred to the research team at the University of Manchester for statistical analysis.

Given that this is a feasibility study (and that there is no control group), we will not be carrying out hypothesis testing to determine if the intervention is effective. Instead, we will focus on (1) estimating recruitment and attrition rates; (2) determining whether there is sufficient change in potential outcome measures following the intervention, using appropriate descriptive measures of central tendency (mean, median) and spread (standard deviation, inter-quartile range, range); (3) estimating the standard deviation of potential outcome measures to inform or refine a sample size calculation for the Phase III trial; and (4) estimating response rates to participant questionnaires, checking for floor and ceiling effects and in fact whether the intervention is acceptable to participating couples. We will reconsider the use of questionnaires or other items if the amount of missing data exceeds 10%.

This study will not include a formal economic evaluation. Rather, the data collected will be used to inform the design and implementation of a full RCT to assess the (cost) effectiveness of the intervention. We will use the service data to identify the range of services used by participants. The service use data will be costed using published unit costs to estimate the likely health and social care costs. Descriptive statistics and regression analysis will be used to identify key cost drivers. Published utility weights will be applied to the EuroQol health measure with 5 levels of severity for 5 dimensions and the Measurement of health-related quality of life for people with dementia and used to estimate quality-adjusted life years. Descriptive statistics and regression analysis will be used to explore the level of association between the two measures and key domain drivers of overall utility and quality-adjusted life years.

The study is approved by the National Health Service Research Ethics Committee (17/NW/0431) in the United Kingdom and the Regional Ethical Review Board in Sweden (Dnr: 2017 2017/281-31).

The approach to obtaining consent is informed by a “process consent” method [47], whereby a researcher enables participants to make informed decision from the point of initial contact to completion of the study [48]. Guided by the Mental Capacity Act [49] and the process consent approach, the researchers will make every effort to ensure that the participants are provided with all the relevant information that they understand the information and are able to retain the information long enough to make a decision and are willing to participate in the study.

People who have capacity to consent will provide either a written or verbal consent. Participants who find reading or writing challenging will have an option of expressing consent verbally, and it will be audio recorded.

A scoping review, conducted earlier on in the study, highlighted the dearth of couple-oriented interventions for couples affected by dementia. Postdiagnostic dementia services and service uptake by people with dementia and their caregivers are quite diverse, depending upon population groups and geographical locations [2,9,50]. The DemPower guide attempts to combine the resources available and act as a single source of information, while providing strategies for managing everyday living. DemPower is particularly aimed at couples who live together at home and where one partner has a diagnosis of dementia. The contents of DemPower have been informed by the experiences of couples who live with dementia and daily life and social situations that include potentially important ways of maintaining a healthy relationship.

Through this feasibility study, we will be able to establish participants’ interest and engagement with the app, how useful and helpful participants find the sections on “home and neighborhood,” “activities and relationships,” and “approach and empowerment.” We also have the opportunity to explore how this app translates into everyday life. This information is crucial for exploring how usual care compares with DemPower and sets stage for a full RCT.

In terms of the study methodology, relevant information on recruitment and attrition rate will inform the future power calculation for a full trial. In the current feasibility study, we test the app in two countries (United Kingdom and Sweden); this will provide insights into if any systemic differences influence the uptake of the app. These data will inform the transferability of the app to various contexts, cultures, and countries.

The diverse cultural and social contexts in the United Kingdom and Sweden might raise some challenges for comparing data and estimating parameters for a full trial, although it does provide opportunities for identifying key areas for consideration in future multinational trials. The design of DemPower is limited and might require further adaptations to make it applicable to people with visual impairments. Finally, differences in recruitment strategies in the United Kingdom and Sweden might influence the recruitment and retention rate.