Special lighting and window glass can help calm Alzheimer's patients, improving their quality of life and making life easier for their caregivers, according to a recent yearlong SIUC study.

Melinda LaGarce, an associate professor of interior design, conducted the research, a follow-up to a preliminary study she did with two other SIUC researchers. (Perspectives reported on that pilot work in spring 1997.)

The research was designed to see if the effects of so-called "sundown syndrome" in Alzheimer's patients could be moderated. As the sun declines in the afternoon, the agitation, aggression, and anxiety shown by many people afflicted with Alzheimer's tends to worsen, sometimes dramatically. The effect begins as early as 2 p.m.

LaGarce designed two identical activity rooms in a local adult services center that provides day care for Alzheimer's patients. Both rooms faced south, were furnished identically, had the same door and window placement, and had similar exterior views.

To the room's users, including the staff, there was also no apparent difference in the lighting and window glass in the two rooms. One of the rooms, however, had full-spectrum rather than standard lighting and special window glass.

Full-spectrum light is a white light similar to noontime sunlight, whereas incandescent light is considerably yellower. Angled microslats in the window glass, which are detectable only on close inspection, blocked direct sunlight during the afternoon, letting in only reflected light.

Throughout the afternoon, a sensor progressively boosted the lighting in this experimental room to maintain a constant level of noontime-intensity light. The lighting/window combo removed any cues, such as shadows, light slant, or color of light, that the sun was setting.

The Alzheimer's patients arrived at the center at noon and stayed until about 4 p.m. year-round. Unbeknownst to them, they were alternated every few weeks between the control room, without the special lighting conditions, and the experimental room. Hidden cameras in both rooms videotaped the group.

A team of specially trained undergraduate and graduate students watched the tapes and recorded instances of agitated or disruptive behaviors common to Alzheimer's patients. They monitored 10 behaviors in all, including anxiousness, wandering, combativeness (such as hitting or throwing things), verbal disruptiveness (such as yelling), and repeating the same action obsessively.

As a quality control check, two members of the caregiving staff also recorded data as observers in the rooms. To ensure objectivity, neither the student team nor the day-care center staff was told how the two rooms differed or what the focus of the study was.

On average, agitation and disruptive behaviors dropped by half during the weeks when the patients were in the experimental room. The greatest reduction--55 percent--occurred in the fall, when the days are getting markedly shorter and the switch to standard time takes place.

Better yet, patients who had the highest levels of agitation in the control room experienced the most dramatic improvements in the experimental room.

The day-care center staff who worked with the Alzheimer's patients also recorded their impressions every day. When the room with the special lighting was being used, they reported that patients were "more calm, content, alert, slept longer during naps, and gave better verbal responses."

The study's findings were published in the autumn 2004 issue of the Journal of Architectural and Planning Research.

LaGarce thinks that nursing homes and elder care centers could put Alzheimer's patients more at ease fairly inexpensively, by using full-spectrum bulbs for lighting and placing louvers or trellises outside of windows to control afternoon light and shadows. Costly microslat glass is probably not necessary.

LaGarce suspects the key to helping Alzheimer's patients lies more in the color of the ambient light than in light intensity or in removing shadow cues. To begin testing that theory, she did a small pilot study in summer 2004 looking at the effect of specific wavelengths of light on two people with Alzheimer's disease.

Each subject spent five 3-hour sessions with an attendant in a room with no windows. LaGarce used color gels to change the room's lighting to different colors for the five sessions--red light for one session, blue light for another, and so forth. The study tested the effect of blue, green, yellow, and red wavelengths, as well as a pure white.

While blue light was very calming to the Alzheimer's patients, LaGarce found that white light allowed them to be more attentive, alert, and relaxed and to function better. But when the ambient light was yellow or red, the patients' agitation grew markedly worse and their functioning declined.

Sharon Smaga, a professor of family medicine at SIU's School of Medicine, served as a medical consultant for the study. Physiologist Luciano Debeljuk, a professor in the School of Allied Health, tested subjects' blood before, during, and after the lighting intervention to measure the levels of certain chemical substances.

"There are certain neurotransmitters and hormones, such as melatonin, that we know are susceptible to light-induced changes and influence behavior," says LaGarce. "We want to see how our behavioral observations correspond with something we can measure in a test tube."

Levels of some substances did change depending on the lighting. But the pilot study's medical goal was to work out the methodology for blood assays for a larger, long-term wavelength study that LaGarce, Debeljuk, and Smaga hope to do.

For this project LaGarce plans to use a computer-controlled bank of LED lights that will allow her to easily produce any color of light. "With the software, you can pull up more blue, or more red, or whatever you want," she explains.

LaGarce also plans to include a second group of subjects in this long-term project: children who have attention deficit/hyperactivity disorder (ADHD). A colleague familiar with her work told her of parents' anecdotes suggesting that ADHD behavior also might be influenced by light. So undergraduate researcher Kandace Fisher, a student in interior design who assisted with the pilot study, tabulated the effects of the different lighting schemes on a boy with ADHD. The boy was significantly calmer and more "on task" with pure white and yellow light than with red or green light, Fisher found.

"There was a huge difference," LaGarce says--enough for her to plan to expand her research to this group as well.

Since LaGarce began her Alzheimer's research several years ago, a number of other researchers have begun investigating the Alzheimer's/light connection. But most are looking at light levels, not light wavelength, which LaGarce believes is the "real secret" to alleviating sundown syndrome.

"If we can define which wavelengths are having the greatest effect," she says, "we can 'prescribe' lighting to help these patients."

--by Marilyn Davis, ed.