The difference between Bright Light Therapy and Biodynamic Lighting for patiënts with moderate-to-severe dementia: a double-blind, randomized, placebo-controlled trial.

Since the early 1990s, several studies have evaluated the effect of bright light in eldery people with dementia. Frequently reported positive effects are improvements of sleep quality, cognition, mood and agitation. Recently biodynamic lighting is upcoming and already implemented in several nursing homes for patients with dementia. Biodynamic lighting is a technical method of achieving the biological effects of daylight in an artificial lighting environment. This method of lighting mimics the cycle of natural daylight, changing colour temperature and intensity throughout the day. The changing colour temperature and intensity throughout the day stimulates the production of sleeping hormones like melatonine and corticol, and in turn improve sleep-wake rhythm. The reported effects from clinical practice seems promising. However limited research has been done on the effectiveness of biodynamic lighting on the sleep quality, mood, cognition and quality of life In patients with dementia. The added value of biodynamic lighting to bright light therapy is also unclear. This study investigate the effectiveness of biodynamic lighting in community-dwelling patients with dementia. 60 patients with dementia (randomly placement) are exposed to either bright light therapy (3 months) and biodynamic lighting (3 months) in the living room of a psycho-geriatric ward, including two delayed periods (3 months each) with standard lighting (placebo intervention). The short-term effect (3 months) and long-term effect of the interventions (6 months) will be investigated and compared between de different lighting conditions.

the present study investigates whether Circadian adjusted LED-based (biodynamic) lighting improve cognitive functions, circadian rhytm, behavioral problems (apathy and agitation), Quality of life and mood (depression) in patiënts with moderate- to severe dementia in comparison with a placebo.

Second, the present study investigates whether bright light therapy improve cognitive functions, circadian rhytm, behavioral problems (apathy and agitation), Quality of Life and mood (depression) in patiënts with moderate- to severe dementia in comparison with a placebo.



Third, the present study investigate whether the effects on the outcome measurements differs between bright light therapy and circadian adjusted LED-based lighting. So the question arise what is the added value of circadian adjusted (biodynamic) LED-based lighting to bright light therapy?

Every patiënt starts with bright light therapy, followed by a wash-out period (placebo). After the wash-out period of bright light therapy, circadian adjusted LED-based lighting will be implemented, followed by again a wash-out period.



Every intervention start with a pre-measurement (one week before intervention starts), a post measurement (3 months after start intervention) and a follow-up measurement (6 months after start intervention). In total the patiënts will be followed for 12 months and there will be five measurements in total.



There will be controlled for seasonal effects by starting the intervention (N = 30) in the autumn (october 2018) and spring (N = 30, april 2019).

The group patiënts (N = 60) are divided over 6 living rooms of a nursing home 'Atlant' in Apeldoorn, The Netherlands.



All patiënts are exposed to bright light therapy (lux 1000-2500, 10 AM- 6 PM), Circadian adjusted LED-based lighting (0 - 2500 lux, 2700-6500K, 9 AM- 11 PM) and placebo light (standard light intensity, 300 lux, 10 AM - 6 PM). Every intervention and placebo periods lasts 3 months.