Impact of dynamic light exposure on sleep-wake pattern and BPSD in people with dementia living at home

Dementia is related to disturbances in the sleep-wake pattern, behavioural and psychological symptoms of dementia (BPSD). These phenomena are the main reason for institutionalization. Assistive light technology is relevant to study, as mitigation of BPSD may allow for the improvement of quality of life for both people with dementia and their caregivers. Studies of dynamic light exposure in home-dwelling populations are scarce. In this single-case experimental design study, we evaluated the effects of exposure to dynamic light on the sleep-wake pattern and symptoms of depression, agitation, and anxiety in 11 home-dwelling people with dementia. A four-phase light-exposure therapy oscillating between the control and intervention waves was offered. Objective and questionnaire data were analysed and discussed. The results show that the used dynamic light system did not significantly affect the sleep variables. The severity of BPSD fluctuated in the expected pattern, reducing in intensity with increased light exposure. This pattern was significant for depression and agitation. This longitudinal study included an exploration of a low-cost assistive light intervention within a hard-to-study home-dwelling dementia population. The lessons learned are discussed and recommendations are made for future studies, as this design seems suitable for studying lifestyle interventions to support home-dwelling people with dementia.