DIMENSIONS Spring 1999

SPOTLIGHT ON RESEARCH: EFFECTS OF LIGHT THERAPY ON AGITATED AD PATIENTS

by Julie Cleveland

Agitated behaviors, such as noisiness, verbal outbursts, and resistance to care, often cause added stress and difficulties when caring for someone with Alzheimer's disease (AD), whether the individual is at home or in a nursing home. Most treatments for agitation involve drug therapy and physical restraint. Recognizing the need for additional environmental treatments for agitation, a team of researchers led by Dr. Margaret Dimond at the UW School of Nursing, have been investigating whether increased light in the evening decreases agitation and improves sleep in people with Alzheimer's disease.

Previous studies suggest that light therapy can reduce agitated behavior in cognitively impaired older adults, but more studies are needed. One of the major theories for what stimulates an increase in agitated behaviors in dementia is altered circadian rhythms and disturbed sleep/wake patterns. Many human bodily functions, such as sleep, exhibit a circadian (about a day) rhythm pattern believed to be timed by an internal clock (within the brain). These cyclic functions are susceptible to change by external signals, a significant one being exposure to light and dark. Many older individuals, including nursing home residents, live mainly indoors and are exposed to very low levels of lighting, possibly threatening the circadian rhythm pattern, and thus their sleep quality.

The story is complicated, however. Genes interact with each other, and with the environment, and many different biochemical pathways can lead to the same result. The challenge for AD researchers is to tease apart those interactions and isolate the individual pathways so that interventions tailored to a specific biochemical pathway can be developed.

Dr. Dimond and her colleagues Drs. Joan Shaver, Carol Landis, David Avery, and Marty Lentz have recently completed a study on cognitively impaired older adults in nursing homes to: 1) test the effects of evening light therapy on agitated behaviors; 2) determine whether the effects of evening light therapy on agitated behaviors are associated with sleep disturbances, circadian rhythm timing (measured by body temperature), or nighttime hormone levels; and 3) determine whether a person's characteristics (such as length of stay in the nursing home, depression, levels of cognitive impairment, and type of dementia) are related to the effectiveness of light therapy in reducing agitated behaviors. Dr. Dimond's study is significant because it looks at a larger number of subjects, and examines more variables related to agitation and light therapy than have past studies. Thus the results may be more likely to represent the general agitated AD population.

Sixty-three residents with dementia from eight nursing homes were selected to participate, and randomly assigned to both the treatment and placebo conditions, with a two- week period between each condition. The light therapy treatment condition consisted of incandescent lighting mounted on the ceiling above the subject's bed, which emitted light for 90 minutes while the participant was being prepared for bed. The light emitted 2500 lux of light, and gradually dimmed to mimic sundown. The placebo condition consisted of the same physical lighting set up, but no light was emitted. Each condition was carried out for 14 days. Measures included observation of the participant's behaviors and activity levels; body temperature; and nighttime hormone levels (urine melatonin and cortisol). Measures were taken four days before treatment or placebo, and during the last four days of treatment or placebo. Research assistants observed the participants' behavior every 20 minutes for 4 hours in the morning and 4 hours again in the afternoon and early evening. The observed agitated behaviors that were recorded included different types of vocalization, tapping and banging, picking at clothes, trying to escape, searching, and pacing. Movement levels and body temperature were measured by activity monitors that were worn by participants in the pockets of a comfortable, light-weight vest.

The results of the study are in the beginning stages of analysis. So far, the results are mixed. Observations of participants' behavior indicate that for both the treatment and placebo conditions, agitated behaviors decreased. The activity monitors which measured the participants' movements show a rather noticeable decline in agitated behavior during the morning hours, but no change or higher agitated behavior in the evening for both conditions. This might be seen as "sundowning," when people seem to get more agitated when the sun goes down. Replies Dr. Dimond, "Unfortunately or fortunately, although we are not sure how to interpret it, in many cases they improved under both conditions." The results of the association with circadian rhythm, sleep disturbances, hormone levels, and a person's characteristics have not been analyzed yet.

One possible reason the results of this study conflict with prior studies is that prior studies did not include a placebo condition, whereas this study did. Thus, one question to ask is whether the improvement of agitated behaviors was due to light therapy, or to the additional attention the participants received from research assistants or from being observed by the research staff. Future studies are needed to address this and further questions related to agitation and sleep.

Agitation is a very difficult situation for families and nursing home workers. "The biggest difference or impact that light therapy could make," says Dr. Dimond, "and what I was interested in, was trying to find something that wasn't a drug, had no serious side effects, and that would diminish agitation without being expensive. That's what my goal was." If researchers found that light therapy generally works, home caregivers and nursing home staff would have a relatively inexpensive, non-invasive, and easy treatment to improve agitation in people with dementia. "I would think that people could put it in their homes and perhaps have a quieter, more manageable environment."

For more information on this study, contact Dr. Dimond at (206) 685-3778, or via email at dimond@u.washington.edu.


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