November 9, 2012

Dementia: Impact of Light, Melatonin, and Circadian Cycles


I’m taking the family to Iceland later this month to see – we hope – the Northern Lights. 

At this time of year, the island nation gets only about five hours of light a day. The nights are very long – good if you’re hoping to see the Aurora Borealis, bad if you’re one of the millions of people who suffer from Seasonal Affective Disorder (SAD). I’m not really one of them, but I’ve still been wondering how I’ll feel during a week with really brief, dim daylight. I even get mildly depressed when we switch back to standard time.

And so, I was especially intrigued by a series of articles about light, mood, and dementia I just saw at AlzheimersWeekly.com.

Blue-White Light, Sleep Tight
In one very small study involving male patients with dementia in a long-term care facility, blue-white lights were installed in the main room, where patients ate their meals and participated in activities.

Blue-white light is most like real daylight, and researchers thought that simulating daylight would encourage patients to remain active and awake during the day. The extra boost, they hoped, would help regulate the men’s sleep-wake rhythms -- associated with the 24-hour biochemical “circadian” cycle of the hormone melatonin -- enabling them to get deeper, satisfying sleep at night.

The men adjusted to the new lighting, and reacted generally as researchers hoped. Said investigator Patricia Higgins, associate professor at the Bolton School of Nursing: "While the group was small, the results show promise in raising activity levels during daytime hours and increasing sleep at nighttime."

Researchers now plan to recreate the study with larger patient populations. They also hope to use their studies to convince hospitals to change their lighting – a safe, non-invasive, drug-free element -- so patients can enjoy speedier recoveries through enhanced wellness... the wellness that comes from a better night’s sleep.

Light: Different Colors for Different Times
In another study involving light’s effects on people with dementia, Dr. LuAnn Nowak Etcher, assistant professor of nursing at Wayne State University, identified benefits of using different hues of white light at different times of day on her patients.

Among other conclusions, she found that her patients reacted to blue-green white light (the kind of light we see at noon, when the sky is deep blue… which some people actually describe as “harsh”) in interesting ways:
  • Patients seemed more awake and alert. 
  • People with dementia were more verbally competent. 
  • Alzheimer's patients showed improved recognition, recollection and motor coordination. 
  • The patients seemed to recapture their personalities and were more engaged with their environment. 
  • Patients' moods also were described as improved. 
On the other hand, patients responded to red-yellow-tinged white light (called “warm” or “soft” white, the kind of light we see at sunrise or sunset… and the type of light we get in most regular incandescent bulbs we use at home) in other ways:
  • Patients were calmer. 
  • People with dementia had reduced resistance to care. 
Dr. Etcher has also conducted light experiments on the condition called “sundowning,” the general agitation dementia patients often experience around dinnertime. When Alzheimer’s patients are restless and irritable at that time, they typically have trouble getting to sleep at a normal hour. Though this study, too, was very small, Etcher has had some success using light therapy to help regulate and normalize circadian cycles in these patients. She explained:
If they sleep better at night, and are more awake during the day, they can eat, they can interact with other people and they can take advantage of other cueing agents in the environment. In addition to light during daytime and darkness during the nighttime, smells at mealtimes, food intake, interactions — all these things in conjunction help regulate our day. 
Bright Lights and Melatonin
In a Dutch study, researchers installed bright lights and administered melatonin to test regulation of the sleep-awake cycle in patients with dementia.

An article from the Journal of the American Medical Association (JAMA) included this comment about the study:
In elderly patients with dementia, cognitive decline is frequently accompanied by disturbances of mood, behavior, sleep, and activities of daily living, which increase caregiver burden and the risk of institutionalization. These symptoms have been associated with disturbances of the circadian rhythm (the regular recurrence, in cycles of about 24 hours, of biological processes or activities). The circadian timing system is highly sensitive to environmental light and the hormone melatonin and may not function optimally in the absence of their synchronizing effects. In elderly patients with dementia, synchronization may be [diminished] if light exposure and melatonin production are reduced. 
Researchers placed bright lights in six of 12 elderly care facilities, and kept those lights on from 9am to 6pm. Some patients randomly received 2.5mg of evening melatonin; others, a placebo. Study leaders hoped to help regulate the participants’ circadian cycles: better wakefulness, better sleep.

189 facility residents participated in the study for about 15 months. The average age was 86; 90% were women; 87% had dementia. Here’s what happened:

The bright lights:
  • reduced cognitive deterioration by 5%, 
  • reduced depression by 19%, and 
  • enhanced general functioning in over half the patients. 
Melatonin:
  • Cut falling-asleep time by 19%, 
  • Increased sleep duration 6%, 
  • Created some moodiness and withdrawal, which could be tempered by addition of bright lights. 
Together, the lights and melatonin reduced aggressive behavior 9%.

The JAMA article offered this summation:
In conclusion, the simple measure of increasing the illumination level in group care facilities [improved] symptoms of disturbed cognition, mood, behavior, functional abilities, and sleep. Melatonin improved sleep, but its long-term use by elderly individuals can only be recommended in combination with light to suppress adverse effects on mood. The long-term application of whole-day bright light did not have adverse effects, on the contrary, and could be considered for use in care facilities for elderly individuals with dementia. 
A Quick Personal Note
As someone who has struggled with – and for now, triumphed over – the demons of insomnia, I know how important home lighting can be. Next to my favorite rocking chair in my living room is a reading lamp with a bright blue-white light that creates a kind of focused indoor daylight. It’s very easy to read by that light, a brightness which may also help regulate my own awake-asleep rhythm more than I know.

And so… on to Iceland! I may need a little extra light therapy time by my bright reading lamp when I get back.

Additional resource:
Lighting is one key way caregivers can improve the quality of life -- and safety -- for people with dementia. This interesting article offers lots of other useful suggestions, too.


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