Pilot Study Person-centred Tablet Intervention

Measured with the revised 30-item Self-Management Ability Scale (SMAS-30). Change/ difference between baseline and post-intervention. It consists of six subscales: Taking Initiative, Self-efficacy, Investing, Positive Perspective, Multifunctionality, and Variety. Each subscale consists of five items scored on a 5-point or 6-point Likert-type scale. A 5-point scale is used for 'Self-efficacy' (1 = I certainly do not think so, 5 = I certainly think so) and 'Positive Perspective' (1 = No!, 5 = Yes!), and a 6-point scale is used for 'Taking Initiative', 'Investing', and 'Multifunctionality' (1 = never, 6 = very often), and 'Variety' (1 = none, 6 = more than six). Item scores are transformed into scores ranging from 0 to 20. Mean subscale scores range from 0 to 100, as does the total score, which is the mean score of the six subscales. A higher score indicates more self-management abilities.

Measured with a short version of the Pleasant Activities List (PAL). Change/ difference between baseline and post-intervention. The PAL was used to assess the frequency and enjoyability of daily and social activities. In this study, the PAL was shortened from its original 139 item to 31 items divided into two subscales: Social Activities (SA), such as visiting family, and Domestic Activities (DA), such as gardening. Shortening was done for two reasons: the length of the original version was thought to be not feasible for the PwDs and a focus on social and domestic activities was more in line with this study. Items relate to the frequency of engagement and the subjective enjoyability, which are scored on a 5-point Likert-type scale ranging from 1 (not at all) to 5 (very much). A higher score indicates that activities are done more often and enjoyed more.

Measured with one item of the Adult Social Care Outcomes Toolkit (ASCOT). Change/ difference between baseline and post-intervention. Responses on this item are given on a scale ranging from 1 ('I have as much social contact as I want with people I like') to 4 ('I have little social contact with people and feel socially isolated'). A higher score indicates less social participation.

Measured with the Short Sense of Competence Scale (SSCQ). Change/ difference between baseline and post-intervention.The SSCQ contains of seven statements. Informal caregivers had answered these questions on a 5-point-likert scale which ranges from 'agree very strongly' to 'disagree very strongly'. For feeling of competence, the scores on all items were summed to get a sum-score. The sum-score ranges between 7 and 35 and a higher score indicates a greater feeling of competence.

Measured with the Dutch version of the 10-item General Self-Efficacy Scale (D-GSE scale). Change/ difference between baseline and post-intervention. Responses are structured on a 4-point scale ranging from 1 (not at all true) to 4 (exactly true). A total score ranging between 10 and 40 is obtained by summing the responses on all ten items; a higher score indicates more self-efficacy.

Measured with the 12-item Experienced Autonomy List (EAL). Change/ difference between baseline and post-intervention. Responses are scored on a 5-point Likert scale ranging from 1 (totally disagree) to 5 (totally agree). Responses to negatively worded items are reverse-coded. The scores on all items were summed to get a sum-score. The sum-score ranges between 12 and 60. A higher score indicates more perceived autonomy.

Measured with the Dementia Quality of Life scale (DQoL). Change/ difference between baseline and post-intervention. It consists of 29 items that are focused on five domains: self-esteem, positive affect, negative affect, feelings of belonging, and sense of aesthetics. All items are rated on a 5-point Likert-type scale. Responses on 'sense of aesthetics' relate to enjoyment and range from 1 (not at all) to 5 (a lot). Responses on the four other subscales relate to frequency and range from 1 (never) to 5 (very often). Scores for the subscales are calculated by computing the mean score. In addition, the DQoL contains one global item to assess overall quality of life on a scale from 1 (bad) to 5 (excellent). A higher score on both the subscales and the global item indicates a higher quality of life.

Measured with the Positive Experience Scale (PES). Change/ difference between baseline and post-intervention. The PES is an 8-item scale. The answer categories were: (1) agree , not agree/not disagree and disagree, whereby not agree/not disagree are took together as (0) disagree. The scores on all items were summed to get a sum-score. The sum-score ranges between 0 and 8, whereby a higher score indicates more positive care experiences.

Measured with the EuroQol-5 Dimensions-5 Levels scale (EQ-5D-5L). Change/ difference between baseline and post-intervention. The EQ-5D-5L consists of five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Informal caregivers had the following answer options on these dimensions: (1) no problems, (2) slight problems, (3) moderate problems, (4) severe problems or (5) extreme problems. A mean sum-score was calculated on these dimensions which ranges from 1 till 5, whereby a higher score indicates more problems. Besides that, the EQ-5D-5L consists of the EuroQol Vertical Visual Analogue Scale (EQ VAS), which contains of a 20 centimeter vertical scale ranging from 0 till 100. Informal caregivers rated their health on this scale, whereby a higher score indicates a better health.

Measured with The Older Persons and Informal Caregivers Survey Minimum DataSet (TOPICS-MDS). Change/ difference between baseline and post-intervention. In the quality of life topic of TOPICS-MDS informal caregivers were asked to rate their current quality of life on a five-level response scale which ranges from 1 (excellent) till 5 (poor). Besides that, informal carers rated their quality of life in comparison with the previous year on a five-level response scale which ranges from to 1 (much better) till 5 (much worse), whereby a lower score indicates a better quality of life. The last question which informal caregivers answered was about their perceived quality of life. Informal carers answered this question by rating their present life on a scale of 0 till 10, whereby a higher score indicates a better life.