I’ve recently been asked a lot about the use of coloured lighting to influence the behaviour and well-being of people with dementia in care settings. A brief look at easily available research indicates that how light affects everyone (including older people) depends on a lot of variables. The effect in a care home is related to wide range of things that are not immediately obvious
- metabolism of melatonin by blue spectrum such as daylight in the morning or screens at night
- the difficulty of seeing things easily when your eyes get older with more "yellowing” inside your eyes – as if you are wearing tinted lenses indoors
- the added importance of being able to see things when you are cognitively impaired (as in dementia) and can’t remember where they are, in an unfamiliar environment
- the behaviour of staff and residents especially at night
- the acoustic and lighting design of a building
- daytime activity.
I could list more!
The research on how blue spectrum light wards off sleepiness has focussed recently on the use of tablets and phones at night. Noticeably with young people, a couple of hours of looking at a blue tinged screen after dark will disrupt sleep patterns, as parents and teachers are aware.
If you are tired, being in low light might make anyone tend to sleep even in day time but light will wake you. That's why night shift workers shut their curtains to sleep in the day. Light will keep you awake even if you are tired, and conversely dark surroundings will make you more inclined to drop off to sleep even if you are not already tired. Bright moon light at night can disturb sleep patterns.
If an older person is cognitively impaired, they may get up at night to investigate lights, even if the light has been explained to them already. If they have not exercised enough they will not feel sleepy. Older people are known to "need less sleep" so if they go to bed too early they will wake up quite refreshed at an inconvenient time for everyone else. And wonder what the light is…
If an old person is taking some medications, this may cause day time inertia, making them less physically tired at night time. They have less melatonin than younger people and it has been said that melatonin levels are even lower in dementia. Everything conspires against a long and peaceful sleep. A cosy bed in a cool room seems to improve sleep. Being too hot is disturbing, and not being able to get a fresh draught of air from a window can upset some sleepers. Many care settings don’t allow open windows, or temperature control in each individual room.
The slightest unfamiliar noise will easily wake an agitated or anxious person, and many people in care homes are agitated. Care homes are in any case noisy at night, even when staff tell you they are not. They are almost certainly noisier than the domestic house the resident moved from. Central heating, traffic noise, night staff, other residents moving about or calling out, washing machines rumbling in the basement...it all adds up to unfamiliar noise, which is known to increase wakefulness. Also, in dementia, it will be hard to get accustomed to it. After a day or two in a strange hotel I don't notice the noise of the air conditioning, lift or heating system. If I had dementia it might be "new" every night, because people with dementia find "familiarisation" harder to achieve.
In conclusion, there are very many things that affect the person apart from the colour and intensity of light, so a lighting system that allows variation is only part of a solution. And there are other parts that are less complex and expensive to alter but which have a greater proven effect.
So, should you invest in a new lighting system? There is some research (not much) on the use of EXTREME bright light in the day time from the Journal of the American Geriatrics Society, and more recent studies on the challenges in studies of bright light therapy to treat sleep disorders in nursing home residents with dementia. I can't find anything that proves changing just the colour of light throughout the day is supported by more than anecdotal evidence. But as always, my readers may have other research that I can look at. Send it to me!