Testing a single-case experimental design to study dynamic light exposure in people with dementia living at home

Most people with dementia live at home supported by informal caregivers, but disturbed sleep patterns may induce a heavy burden of care. The beneficial effects of bright light on their sleep, health, and well-being have been demonstrated in clinical settings, but not in a home situation. We evaluated a dynamic lighting system in a real-life longitudinal single-case experimental design (SCED) with people with dementia living at home. Eleven people with dementia and their informal caregivers were included in this study with four 4-week periods of alternating exposure and nonexposure in an introduction–withdrawal setup (ABAB). Objective light exposure data were collected and analyzed. The used study design seems applicable for this population and suitable for home use. Participant dropout did occur, but was due to health conditions rather than participant burden. The lighting system led to more light in the homes of the participants, as well as to higher actual individual light exposures, although the latter increased only moderately and not consistently across all participants, seasons, and times of day. The participants appreciated the lighting system even after 6 months. We reflect on individual differences, seasonal and daypart influences, and differential light effects. Recommendations and lessons learned are discussed.