This study aims to develop a mobile app for caregivers and tests its feasibility for a period of 8 weeks. A mixed-method study design with both qualitative and quantitative components will be used. A maximum of 36 caregivers will be involved in the six focus groups. Each focus group interview will involve 6 caregivers of persons with dementia. Another 30 caregivers will be involved in the 8-week trial use of the app. Each focus group interview will last for about 1.5 hours, facilitated by a moderator. Before and after the 8-week trial use of the app, four outcome measures (Zarit Burden Interview, Self-rated Health, Patient Health Questionnaire, and Modified Medical Outcome Study Social Support Survey) will be taken. This study will provide evidence of the feasibility of the use of the newly developed app among caregivers.

Background Caregivers of persons with dementia experience tremendous stress Caregivers of persons with dementia (PWD) in Hong Kong reported high level of stress due to caregiving (Cheung et al., 2015). Caregiver stress was defined as "an unequal distribution of responsibilities on the caregiver as a result of caring for someone with a prolonged impairment" (Pearlin et al., 1990 cited in Llanque et al., 2016). Providing care to PWD persons imposed tremendous stress on caregivers as PWD often performed problematic behaviours that might affect others (Kang et al., 2006). PWD's dependency in activities of daily living, severity and frequency of behavioural symptoms was found to be significantly associated with caregivers' depressive symptoms (Lee et al., 2017). Another source of stress was caregivers' feeling of overload, which was considered as subjective stressor (Son et al., 2007).

Use of mobile applications in stress management Mobile applications (apps) have been developed in stress management. Persons suffered from post-traumatic stress disorders have been selected as targeted population to assess feasibility and acceptability of apps to manage acute stress or stress symptoms (Kuhn et al., 2014). From the users' perspective (as stated in focus group interviews), using app was considered as 'acceptable and helpful' tool for stress management (Kuhn et al., 2014). Activities could be scheduled by the app and this arrangement was welcome by app users (Kuhn et al., 2014). Apps are considered as potentially effective self-management tool for persons suffered from stress (Kuhn et al., 2014).

New feature of the mobile app: e-painting Evidence had shown that intervention of art therapy reduced stress symptoms among paediatric patients (Chapman et al., 2001), working adults (Karpaviciute & Macijauskiene, 2016), and older adults (Walker et al., 2016). Group interactions among participants in art therapy contributed to its effectiveness, thus group therapy was recommended as 'best practice' (Spiegel et al., 2006). Painting (or visual art production) is recommended because looking at painting (or cognitively evaluated artwork) does not show similar effect on stress reduction in adulthood (Bolwerk et al., 2014). Using functional MRI (fMRI), Bolwerk and team (2014) found that those who participated in visual art production showed greater spatial improvement in functional connectivity of posterior cingulated cortex to the frontal and parietal cortices after the intervention than those who cognitively evaluated artwork at a museum. This implied that painting, but not viewing art work, had effect on psychological resilience in adulthood (Bolwerk and team, 2014). A review (Slayton et al., 2010) summarised that a brief period of painting significantly reduced anxiety score (Sandmire et al., 2012; Curry & Kasser, 2005), distress (Franks & Whitaker, 2007), depression (Gussak, 2006) but increased mental alertness and sociability (Rusted, Sheppard, & Waller, 2006).

Based on the knowledge in the production of painting and its possible impacts on caregivers' emotion (anxiety, stress, depression) and sociability, we plan to develop a mobile application which allows caregivers to create their own e-paintings and share with others.

Objectives of the study

1. To identify caregivers' preferred functions of the app and training needed to use the app;
2. To assess the trial process and procedures (estimate the recruitment rate, dropout rate, the compliance of emotional assessments in the app);
3. To collect app users' comments on the use of the app after the 8-week trial;
4. To examine the consistency of the effects of the app intervention on emotion.

Methods This study adopts a mixed method (qualitative and quantitative method).

Qualitative component comprises of six focus group (FG) interviews. FG 1-3 aim to explore the caregivers' preferences of the features of the e-painting mobile app. FG 4-6 aim to collect the app users' views on the use of the app after the trial period of 8 weeks.

Guiding questions for Focus Group 1-3:

1. What functions are preferred by the caregivers in the e-painting app?
2. What kind of training do caregivers need before they use the e-painting app?
3. What kind of follow-up do caregivers expect after using this app? Analytical results of their paintings in form of a prop-up message? Connection to health professionals who could provide help to the caregivers?

Guiding questions for Focus Group 4-6:

1. What did the app users (caregivers) think about this app?
2. What did the app users like or dislike most about the app?
3. What feature should be added to the app so as to support the app users?
4. Did the app users enjoy the use of this app to draw their paintings? Why?

Quantitative component of the study is the trial run of the app over a period of 8 weeks with 30 caregivers. Participants will be asked to download the app to their mobile phone and use the app at least two times per week. They will be asked to go through a set of emotion assessments in the app before and after the 8-week trial. The following measures will be included in the emotional assessments:

1. Caregivers' level of stress (measured by a 11-item Zarit Burden Interview, CZBI-Short, Tang et al., 2015) (Primary outcome)
2. Self-rated health status (measured by the 1-item self-rated health likert scale) (Secondary outcome)
3. Depressive symptoms (measured by a 9-item Patient Health Questionnaire (PHQ-9, Cheng & Cheng, 2007) (Secondary outcome)
4. Instrumental and emotional social support (measured by a 8-item Modified Medical Outcome Study Social Support Survey (mMOS-SS, Moser et al., 2012) (Secondary outcome)

E-paintings will be analysed by a certified art therapist through discussions with the participants. Data about colour hue, saturation and brightness will be analysed. Data will be collected in recruitment rate of caregivers who are willing to join the study, the dropout rate at the end of the 8-week trial, and the compliance rate of emotional assessments in the app. Frequency of the participation in e-painting will be collected. Comparison of the app users' stress level, depressive level, self-rated health status and social support before and after the trial will be made.

Subjects. A maximum of 36 caregivers will be involved in the six focus groups. Each focus group interview will involve 6 caregivers of persons with dementia. Another 30 caregivers will be involved in the 8-week trial of the app.

Expected deliverables

1. A e-painting mobile app for caregiver to reduce stress;
2. A presentation in an international conference (reporting app users' comments on the use of the app after the 8-week trial);
3. A paper in an international peer-refereed journal (reporting caregivers' preferred functions of the app, the training needed to use the app, the recruitment rate of caregivers to the study, the dropout rate of participation in the 8-week trial, the compliance of emotional assessments in the app and the consistency of the effects of the app intervention on emotion).

Inclusion criteria:

• aged 18 or above
• provide direct care to a person with dementia
• able to read and communicate in Chinese

Exclusion criteria:

• have fever or influenza symptoms at the time of recruitment
• being hospitalized
• living in a residential care home