For Alzheimer’s Patients, a Glimmer of Hope : Health: Emory University study finds light therapy may ease depression and sleep disorders. But doctor says more research is needed to be sure it is effective, and warns against trying treatment at home.

After many restless nights filled with hallucinations of bears in her bedroom, Eveleth Harshman says she now sleeps soundly after reading a single magazine article.

The same kind of light therapy used to treat the winter blues has alleviated much of the disturbed sleep and agitation the 80-year-old woman suffers as a result of Alzheimer’s disease.

Harshman, who can remember the name of the brain surgeon who operated on her at age 9 but can’t recall her telephone number, is among 30 patients participating in a study of light therapy at Emory University.

Light therapy may enable Alzheimer’s patients to remain at home or ease the problems they have living in nursing homes, said Dr. Robert Green, director of Emory’s Neurobehavioral Program and Memory Assessment Clinic.

“If it works, you would have a treatment option that would be low-cost, low-tech and easily available to care-givers and nursing centers across the country,” he said.

More than 4 million Americans are believed to have Alzheimer’s, which gradually wipes out the memory until its victims can no longer perform even the simplest task. There is no test to definitively diagnose Alzheimer’s; doctors rule out all other possibilities and confirm a diagnosis during autopsy.

The Emory research, funded by the National Institute on Aging, is based on previous studies of people with severe winter blues, or Seasonal Affective Disorder. The depression they experience can sometimes be alleviated by the systematic exposure to high levels of artificial light.

Exactly how the light affects the brain isn’t known, but it apparently affects the levels of two brain chemicals, a neurotransmitter called serotonin and a hormone called melatonin.

Similarly, the brightness and duration of light also affect sleep patterns, restoring a person’s ability to sleep well at night. Disrupted sleep frequently occurs among Alzheimer’s patients, resulting in restlessness, pacing, wandering, irritability and other behavioral problems.

Drugs can lessen those problems, but often result in unwanted side effects. Emory’s Green and his colleagues think that exposing Alzheimer’s patients to bright light may provide a safer way of improving their sleep and alleviating their agitation.

“There are studies that show that this (sleep problem) is in fact one of the things which disrupts family members the most and actually leads to nursing home placement,” Green said.

Dr. Norman Rosenthal, an expert on Seasonal Affective Disorder and a psychiatrist with the National Institute of Mental Health, said the study makes sense.

“Light is known to help consolidate the sleep of some people,” he said. Light therapy would not cure Alzheimer’s, but anecdotal reports indicate it may succeed at relieving some of its symptoms.

“There’s a reasonable hope that some relief could be provided,” Rosenthal said.

Patients entering the study wear a watch-like device on their wrist to measure the amount of light they are normally exposed to and the amount of movement or time they are awake. The patients wear it throughout the four-week study.

After a week spent in normal light, they spend two weeks in light therapy, followed by a fourth week without the light treatment.

During the treatment, participants sit on a pastel sofa in a waiting room facing a bank of six light boxes about 3 1/2 feet to 5 feet high. For 1 1/2 hours, they read or talk with others while the fluorescent light penetrates their eyes. Green estimated that patients receive light about five times as bright as in an office.

Harshman joined the study in April after her son, Bill, learned of the project. Initially, she wasn’t interested, but decided she had “nothing better to do.”

At her first treatment, “they gave me a pile of magazines and I read, and after awhile I realized a lot of time had passed,” said the former teacher. “I was very curious the whole time--and I’m still curious--about what the end result will be.”

The positive results are so obvious to Harshman’s family that they would like her to continue to participate in the research. But Green said that the outcome is uncertain and that many more patients will have to participate to determine whether the therapy is effective.

Green cautioned care-givers against trying to recreate his experiment at home, saying that he has no evidence yet that light therapy is effective.