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DYNAMIC LIGHTING AS A TOOL TO INFLUENCE THE DAY–NIGHT RHYTHM OF CLIENTS WITH PSYCHOGERIATRIC DISORDERS: A PILOT STUDY IN A DUTCH NURSING HOME

2010; Wiley; Volume: 58; Issue: 5 Linguagem: Inglês

10.1111/j.1532-5415.2010.02825.x

1532-5415

Marieke D. Spreeuwenberg, Charles G. Willems, Charles G. Willems, H Verheesen, Jos M. G. A. Schols, Jos M. G. A. Schols, Luc de Witte, Luc de Witte,

Sleep and related disorders

To the Editor: A disturbed day–night rhythm is characteristic of people with psychogeriatric disorders.1,2 For nursing staff, nocturnal restlessness, night wandering, and greater risk of falling of clients are recognizable signals. Unfortunately, the lighting level in nursing homes (∼300 lux) is often insufficient to support clients in their disturbed day–night rhythm.3 The aim of this study was to investigate whether offering dynamic lighting that varies in light intensity (lux) and color (K) improves the day–night rhythm of patients with psychogeriatric disorders. This longitudinal quasi-experimental study lasted 3 months and was conducted at Klevarie nursing home in Maastricht, the Netherlands. The intervention group consisted of 10 of 30 clients on the first ward (Aqua), with special lighting of the types Philips Savio and Philips Rotaris (Philips, Eindhoven, the Netherlands) installed in one of the three common living rooms.4 The control group consisted of 10 of 30 clients of the second ward (Sonne) with no dynamic lighting. Both wards were more or less identical, with a similar level of care provided, type of clients, and design of the living rooms. After a baseline measurement (3 weeks), two schedules of dynamic lighting were offered for 1.5 months each. To give the residents the opportunity to start the day in a relaxed way, both lighting schedules began with a low-intensity, warm light (400 lux, 3,300 K) in the morning, starting at 7:00 a.m. Within 2 hours, the light became more intense and cooler, with a maximum (1,300 lux, 4,900 K) at 9:00 a.m. To give residents the opportunity for rest and relaxation during and after lunch, the intensity and color of the lights decreased gradually 1 hour before lunchtime (12:00 noon) and increased gradually again within 1 hour after lunchtime (1:00 p.m.). In the first lighting schedule, the cool, intense light lasted until 5:00 p.m. and decreased within 1.5 hours to provide a relaxing atmosphere in the evening. In the second lighting schedule, the cool, intense light lasted until 7:00 p.m. Activity registration was performed using a waterproof watch-like unit of the type Vivago WristCare (Vivago Oy, Helsinki, Finland).5 The Vivago WristCare system has a number of sensors sensitive to macro and micro movements. The measurement unit run from 0% (no activity) to 100% (maximum activity). Every minute, the activity measurements of clients were sent wirelessly to base units placed within the wards and stored in a central computer. The Vivago WristCare system provides valid measurements of the day and night rhythm and can discriminate between people with and without dementia.6–8 A random intercept multivariate multilevel analysis was used to study the longitudinal group effects of dynamic lighting. This analysis corrects for potential time-dependent observations. The level 2 variable was residential code (=ID), and the level 1 variable was time (in days). P<.05 was considered significant. The statistical software packages MLwiN (version 2.1, MLwiN, Version 2.02. Centre for Multilevel Modeling, Bristol, UK) and SPSS version 16.0 (SPSS, Inc., Chicago, IL) were used to analyze the data.9,10 Figure 1 shows the mean activity curves (standard error) during the baseline and the first and second lighting schedules in both groups. In the intervention group, the first lighting schedule had a large influence on the activity level of clients, leading to reduced activity during the daytime (7:00 a.m. to 9:00 p.m.) (B=–8.5, 95% confidence interval (CI)=−12.6 to −4.4), P<.001), during the night (9:00 p.m. to 7:00 a.m.) (B=−3.7 (95% CI)=−7.5–0.1, P=.06), and during the early evening (5:00 p.m. to 7:00 p.m.) (B=−8.3 (95% CI=−14.2 to −2.4, P=.006) from baseline. Because activity during the night and the day decreased, the ratio of the day–night rhythm remained the same (B=0.07, 95% CI=−0.04–0.17, P=.21). During the second lighting schedule, the clients in the intervention group showed less activity during the daytime (B=−6.4, 95% CI=−10.4 to −2.4, P=.002) than at baseline. No other differences were found. Mean activity scores±standard error at baseline and with the first and second lighting schedules for the control group (Sonne) and the intervention group (Aqua). The effects found should be interpreted with some caution. First, it appears that, at the individual level, people respond differently to dynamic lighting. Second, the number of people involved in the study was too small to draw firm conclusions. Therefore, the research team believes that more research is needed before results can be fully interpreted. Although the effects of dynamic lighting seem promising, it should be further explored in a larger setting. We thank the participants and staff of Vivre who made this study possible and Frank Vlaskamp for his valuable input. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. This work was supported by ZonMw, study 88100241 and College Bouw, Utrecht, the Netherlands. Author Contributions: MDS: study concept and design, analysis and interpretation of data, and preparation of manuscript. CW, HV, JS, and LW: study concept and design, interpretation of data, and preparation of manuscript. Sponsor's Role: None.