The Right Light at the Right Time Helps Dementia
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EmailLight therapy in dementias such as Alzheimer's isn't just about brightness. Researchers found the right color temperature and good timing can have a positive impact on mood, behavior and even sundowning.
What is "color temperature"? See the video to the right.
A Wayne State University researcher found that getting the maximum therapeutic effects from exposure to light hinges on using the right shade of white light at the right time. The study was published in the Western Journal of Nursing Research.
Cool White Light
Blue-green light was perceived by caregivers as having improved global functioning of patients, according to researcher LuAnn Nowak Etcher, Ph.D., assistant professor of nursing.
Caregivers said patients receiving light-therapy treatments in the bluer parts of the spectrum showed noticeable improvements, including:
- 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.
Warm White Light
Warm light is white light with a red-yellow tinge to it. Although the experiment was meant to test the effects of blue-green light on dementia patients, to do so Dr. Etcher had to also have a placebo group that was exposed to red-tinged light. Dr. Etcher was surprised when some people in the placebo group, who were living with the red-tinged light, showed a variety of other improvements. In particular, caregivers reported:
- Patients were calmer
- People with dementia had reduced resistance to care.
Choosing Therapeutic Lights for Dementia
When one goes shopping for lamps, most have a "color temperature" on the label. This measure ranges from 2700K (short for 2700 degrees Kelvin) on the red-yellow end of the spectrum all the way to 6500K on the green-blue, or "daylight" end of the spectrum.
Courtesy National Resources Defense Council
All the lamps give off white light, but there are different tinges. Think of a typical morning outdoors, as the sun rises until it reaches its zenith at high noon.
2700K lamps (also called warm white) simulate the kind of light we get outdoors towards sunrise or sunset. Though white, its tinge emanates a warm, sleepy feeling. This would explain the calming, mood improving effect described in the dementia patients above.
6500K lamps (also called daylight) simulate outdoor light at high noon, when the sky is intensely blue, the light is often called harsh and people are the most "awake." Given these characteristics, the cognitive improvements seen in the list above make perfect intuitive sense.
Sundowning & Light Therapy
Previously, Dr. Etcher has done work on "sundowning." This is when some people with a dementia such as Alzheimer's become restless, agitated and irritable around dinnertime, then have great difficulty getting to bed at a normal hour. As part of her doctoral research, she experimented with regulating rest-activity patterns in women with Alzheimer's by using light therapy. Light therapy is a growing intervention for problems related to our "body-clocks", more technically referred to as circadian disorders.
Dr. Etcher described this study as a new effort to resolve disagreement among researchers on the benefits of therapeutic light therapy in regulating rest-activity patterns for people with Alzheimer's.
Light Therapy Study
Dr. Etcher worked with 20 women with Alzheimer's dementia who were 65+ residing in Michigan nursing homes. Each person was randomly assigned to the test-group, which received blue-green light treatments, or to the control group, which was treated by receiving dim red light.
The level of effects varied, Etcher said, noting that while the blue-green group recipients were largely reported by caregivers as showing improvement, a few showed little to no effect from the treatments.
A "light visor" provided the light to patients. These visors are commercially available and are more commonly used to treat people who suffer from depression in winter months, technically referred to as S.A.D. (Seasonal Affective Disorder). Caregivers were then asked to report their ongoing observations. The caregivers consisted of patients' family members and nursing facility personnel. No one explained to the caregivers the hypothesized physiologic effects of each type of light, in order to retain the objectivity of their reporting.
Conclusions & Next Steps
Dr. Etcher concluded that the results qualified the benefits of light therapy as well as its limits. She said,
"Some of the rest-activity pattern disruptions that we see associated with Alzheimer's dementia may not necessarily be circadian based. They may be due to unmet needs, pain or other phenomena, and therefore would not respond to an intervention aimed at regulation of the circadian system."
Calling her study preliminary, she said it now needs to be replicated with a larger sample and different demographics.
In addition to ascertaining which behaviors are circadian based, establishing which methods are most appropriate to analyze data like Etcher's requires exploration, she said. She is proposing further work that uses two different nonlinear analytic methods to examine sensitivity and specificity to detect change in circadian patterns, with a long-term goal of developing interventions to regulate those patterns to the benefit of patients' overall function.
Other benefits were described by Dr. Etcher. She said,
"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."
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Wayne State University is one of the nation's pre-eminent public research universities in an urban setting. Through its multidisciplinary approach to research and education, and its ongoing collaboration with government, industry and other institutions, the university seeks to enhance economic growth and improve the quality of life in the city of Detroit, state of Michigan and throughout the world. For more information about research at Wayne State University, visit http://www.research.wayne.edu.
Source:
Wayne State University - Office of the Vice President for Research
