Testing a Single-Case Experimental Design to Study Dynamic Light Exposure in People with Dementia Living at Home

Inge Bongers,Yvonne De Kort,Liselore Snaphaan,Ellen Van Lieshout-Van Dal,Samantha Bouwmeester

doi:10.3390/app112110221

Inge Bongers, Yvonne De Kort + Show 3 more

Open Access

https://doi.org/10.3390/app112110221

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Abstract

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.

Highlights

Due to age-related changes in the eye, ageing comes with an increasing demand for higher light levels that support good vision and help synchronize one’s biological clock [1,2,3]
Dementia can disturb the biological clock more strongly compared with healthy ageing, which is especially problematic during the darker seasons, such as fall and winter [4]
These symptoms form a high burden for informal caregivers and are the main reasons for institutionalization. The prevalence of these symptoms increases the chances of institutionalization by times [7,8]. Because of their ageing eyes and their neural deterioration, persons with dementia would substantially benefit from extra bright light exposure in their home environment

Summary

Introduction

Due to age-related changes in the eye, ageing comes with an increasing demand for higher light levels that support good vision and help synchronize one’s biological clock [1,2,3]. Exposure to daylight or artificial light at the right time of day is a strong and crucial cue for synchronizing the biological clock. Dementia can disturb the biological clock more strongly compared with healthy ageing, which is especially problematic during the darker seasons, such as fall and winter [4] This can result in the manifestation of symptoms, such as nightly wandering, restlessness, and agitation [5,6]. The prevalence of these symptoms increases the chances of institutionalization by times [7,8] Because of their ageing eyes and their neural deterioration, persons with dementia would substantially benefit from extra bright light exposure in their home environment. Spending significantly less time outside causes further understimulation of their biological clock, and this increases the risk of loss of healthy circadian entrainment [8,9,10,11,12]

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