TABLE 1.
Overview of the studies evaluating ambient light conditions and behavioural and psychological symptoms of dementia or sleep‐wake rhythm in care home settings
| Study [ref.], year, country | Participants | Design; setting and ambient light conditions | Relevant measurement | Main findings |
|---|---|---|---|---|
| Ancoli‐Israel et al., 20 1997, USA | N = 77 (F = 58), mean MMSE = 12.8 (severe dementia, n = 55), mean age 85.7 | Observational cohort study in two nursing homes, natural setting, no intervention | Sleep‐wake behavioural rhythm, light exposure in patients of different degree of dementia, by a wrist‐worn actigraphy for 3 days | Patients with more severe dementia slept more, had more blunted activity rhythms and less bright light exposure |
| Schnelle et al., 21 1999, USA | N = 184 (F = 150), mean MMSE: 10.9, mean age 83.9 | Four‐phase pre‐and‐post in eight nursing homes, natural setting, interventions not involving physical environment modifications (primarily on noise reduction) | Sleep (7 p.m. to 5 a.m.) by wrist‐worn actigraphy. Light changes and noise assessed separately by a bedside cadmium sulfide photocell and an electric microphone, for 4 nights | Light changes reduced 50% with intervention. Wakes from sleep reduction associated with both light change reduction alone and noise + light change reduction |
| Shochat et al., 5 2000, USA | N = 77 (F = 58), mean MMSE = 12.8, mean age 85.7 | Observational cohort study in two nursing homes, natural setting, no intervention | Sleep‐wake behavioural rhythm, mean/median light levels, minutes over 1000/2000 lux, by a wrist‐worn actigraphy for 3 days | Mean/median: 485/54 lux; time over 1000/2000 lux: 10.5/4 min. Daytime light consolidated night sleep, predicted peak activity |
| Song et al., 22 2009, Korea | N = 10 (F = 10), mean MMSE = 13.1, mean age 85.6 | Observational cohort study in a nursing home and an assisted living facility, natural setting, no intervention | Rest‐activity rhythm measured by a wrist‐worn actigraphy. Light measured separately by calibrated precision light metres | Mean p.m. light: 2038 ± 288 lux (common areas)/591 ± 498 lux (bedrooms). All with disturbed rhythm, but influenced by settings for example, scheduled activity |
| Nioi et al., 23 2017, UK | N = 16 (F = 13), mean MMSE = 22, age 72–99 | Repeated measures design comparing same cohort in summer/winter in six care homes, natural setting, no intervention | Sleep‐wake behavioural rhythm by a wrist‐worn actigraphy, light by another lapel mounted actigraphy for 4 days. Visual, cognitive and mental wellbeing compared | More daylight, bright light exposure and activity in summer. Cognitive function correlated positively with sleep latency and visual function |
| Wahnschaffe et al., 24 2017, Germany | N = 20 (F = 19), mean MMSE = 22, mean age 83.8, dementia diagnosed and subtyped with ICD‐10 | Retrospective analysis the impact from season and weather of a dynamic lighting study in one nursing home | Rest‐activity rhythm measured by a wrist‐worn actigraphy for 3 years and compared with daily regional weather data, especially cloud amount and day length | Nocturnal restlessness was positively correlated with cloud amount and negatively correlated with day length |
| Konis et al., 25 2018, USA | N = 77 (F = 56), mean age 85.2, MMSE all above 10 | Two‐arm parallel intervention study in eight dementia care communities, comparing the effect of daylight exposure (8:00–10:00 a.m. within 3 m from windows) | No actigraphy measurement. BPSD measured for 12 weeks with NPI‐NH and CSDD. Light measured separately by a mobile spectrometer able to capture spectral composition of light and transformed to melanopic illuminance (mLux) | Intervention group has significant reduction CSDD score. The reduction was most prominent in probable major depressive disorder patient (CSDD > 10), and positively correlated with average mLux |
| Bautrant et al., 26 2019, France | N = 19 (F = 17), MMSE all below 15, mean age 86.3 | Pre‐and‐post in one nursing home, adjusting setting (change ceiling/wall colour, enhanced daylight, gradual darkening night light; also music, clock, clothes) | No actigraphy and no quantitative light measurement. Number and duration of BPSD recorded with questionnaires. Risk of fall, cognition and depression compared | No difference in risk of fall, cognition and depression. Reduction of agitation, aggression, screaming and wandering observed |
| Juda et al., 27 2020, Canada | N = 14 (F = 12), cog‐ batteries of NIH toolbox (5 scored < 2SD), mean age 82.6 | (*Only control part included.) within‐subject cross‐over design, control used natural settings (conventional light) in one of the two adjacent buildings | Sleep‐wake behavioural rhythm and light exposure by wrist‐worn actigraphy for 5 weeks (control). Cognition, depression, fatigue, sleep quality, chronotype measured | There was a large variability in light exposure for all subjects, irrespective of experimental group. Participants with higher morning light exposure had less fragmented rest‐activity rhythms and higher rhythm amplitude, which correlated positively with cognitive performance |
Abbreviations: CSDD, Cornell Scale for Depression in Dementia; MMSE, Mini Mental State Examination; NIH, National Institute for Health Research; NPI‐NH, Neuropsychiatric inventory‐Nursing Home version.