Stanford Clinic Begins First Long-Term Study in Sleep Apnea
October 23, 2002, Acurian
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Source: Stanford University Medical Center

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Researchers at Stanford University Medical Center's Sleep Disorders Center are set to begin a multicenter clinical trial on a treatment for sleep apnea, a disorder in which people stop breathing sometimes hundreds of times a night for up to a minute each time. It is the largest clinical trial for a sleep disorder ever funded by the National Institutes of Health.

Known as APPLES - Apnea Positive Pressure Long-Term Efficacy Study - the study is funded by a $10-million grant from the National Heart Lung Blood Institute of the NIH.

"This award recognizes the importance of sleep disorders and sleep research, and is consonant with today's emphasis on evidence-based medicine," said William Dement, MD, PhD, director of the center and the Lowell W. and Josephine Q. Berry Professor in the Department of Psychiatry and Behavioral Sciences.

APPLES will examine the long-term effects of using nasal continuous positive airway pressure, or CPAP, to treat sleep apnea. The CPAP device gently blows air into a patient's nose through a mask, preventing the airway from closing. "CPAP is the most effective, noninvasive method of treating sleep apnea," said project director Clete Kushida, MD, PhD, assistant professor of psychiatry and behavioral sciences. Doctors can also treat sleep apnea with a variety of surgical procedures or with dental appliances in mild cases.

Researchers estimate that sleep apnea affects 4 percent of men and 2 percent of women between the ages of 30 and 60. The most common type is obstructive sleep apnea, in which soft tissue at the back of the throat collapses and obstructs the airway. The lack of oxygen eventually rouses the sleeper slightly, enough to open the airway, but the cycle repeats itself as the patient resumes deeper sleep.

Symptoms of sleep apnea include daytime sleepiness and loud snoring. Sufferers also may be restless or make choking noises in their sleep. Untreated sleep apnea has been linked to fatigue, high blood pressure and stroke. It also may affect cognitive functions, such as attention and memory.

Participants in APPLES will use a CPAP device for six months. Half will receive active CPAP and half will use a sham system. The sham system is a placebo, much like the sugar pills used in drug trials. Patients' sleepiness, mood, quality of life and ability to think will be tested four times over the course of the study.

A subset of the patients treated at Stanford will also undergo functional magnetic resonance imaging. Rather than simply lying in the machine, as in conventional MRI, subjects will carry out tasks as doctors scan their brain. "We hope this novel technique will indicate the specific regions of the brain most affected by sleep apnea and also show how these change with CPAP use," Kushida said.

In two preliminary studies conducted at Stanford, which included a total of 16 subjects, consistent use of active CPAP caused patients to be more awake during the day, perform better on memory tests and score higher on a questionnaire about their quality of life. Researchers hope to see similar results in the new study.

"We hope that by establishing the effectiveness of CPAP we can improve access for people denied treatment for sleep apnea," Kushida said.

The study will last five years and include 1,050 patients, each of whom will participate for seven months. Other sites include the University of Arizona, Harvard University, St. Luke's Hospital in St. Louis and St. Mary's Medical Center in Walla Walla, WA. The industry partners are SAM Technology and Respironics, Inc.

APPLES volunteers must be age 18 or older and have no other sleep disorders. Participants will receive $500 if they complete the study. Those interested in participating in APPLES are asked to contact (650) 725-8527.


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