Sleep disorder clinical trial to be largest ever conducted

William Dement

If asked to name the most common chronic illness in the United States, sleep apnea probably wouldn't be the first thing to pop into your head. Yet according to well-known sleep expert William Dement, MD, PhD, no other chronic disease afflicts more Americans than apnea—a potentially fatal disorder in which people stop breathing sometimes hundreds of times a night, often for a minute or more each time.

Dement and his colleagues at the School of Medicine are now recruiting patients for a clinical trial on a treatment for the disease, which Dement said affects 24 percent of men and 9 percent of women between the ages of 30 and 60. The multi-center study, known as APPLES (Apnea Positive Pressure Long-Term Efficacy Study), will include 1,100 patients, making it the largest clinical trial for a sleep disorder ever funded by the National Institutes of Health.

The most common type of sleep apnea 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 over and over as the patient resumes deeper sleep. Symptoms of sleep apnea include daytime fatigue and sleepiness, loud snoring and choking noises during sleep. Untreated sleep apnea has been linked to high blood pressure, stroke and a decline in cognitive functions, said Dement, the Lowell W. and Josephine Q. Berry Professor in the Department of Psychiatry and Behavioral Sciences and professor, by courtesy, of psychology.

Apnea treatment typically involves a special device that gently blows air into a patient's nose through a mask, preventing the airway from closing. Clete Kushida, MD, PhD, associate professor of psychiatry and behavioral sciences, calls the device—known as the nasal continuous positive airway pressure, or CPAP—the most effective, noninvasive method of treating apnea.

Researchers want to learn more about the treatment, and APPLES investigates the long-term effects of CPAP. Preliminary studies conducted at Stanford have been promising: 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.

"The data in our pilot study were convincing enough to apply for this special grant," said Kushida, who hopes to see similar results in the new study.

During the study, participants use a CPAP device for six months. Half receive active CPAP and half use a sham system. The researchers assess patients' sleepiness, mood, quality of life and ability to think over the course of the study.

Participation lasts seven months and includes two training session, several overnight sleep studies, three days of testing and two physician appointments. Participants receive $500 upon conclusion of the study.

Other sites participating in the five-year study include the University of Arizona, Harvard University, St. Luke's Hospital in St. Louis and St. Mary's Medical Center in Walla Walla, Wash.

Volunteers must be age 18 or older and have no other sleep disorders. Those interested in participating should call 736-8871 or e-mail