Overnight Test Best at Spotting Sleep Apnea

WEDNESDAY, Feb. 23, 2005 (HealthDayNews) -- A high-tech overnight sleep test may be the only reliable way for doctors to differentiate plain old snoring from more dangerous sleep apnea, claims a new study.

Obstructive sleep apnea happens during sleep when air flow is impaired into the lungs via the mouth and nose. Sleep is interrupted throughout the night and normal breaths are labored, characterized by loud snorting or choking. Besides causing daytime fatigue, chronic sleep apnea has been linked to increased risks for heart attack and stroke.

Diagnosing sleep apnea can be difficult, however. In their study, researchers at Lugwig-Maximilians University in Munich, Germany, evaluated 101 patients who came to an ear, nose and throat clinic complaining of snoring.

The doctors tried to determine whether the patients had obstructive sleep apnea based on their medical history, an assessment of the anatomy of their nose and throat, and a test looking for obstruction in the throat.

The patients were also given a two-night sleep test involving overnight measurements of snoring, body position, lung oxygen saturation and airflow, as well as electroencephalograph (EEG) brain activity, all recorded by a machine called a polysomnograph. This expensive, cumbersome -- but accurate -- test is considered the "gold standard" in diagnosing sleep apnea.

Unfortunately for patients hoping to avoid polysomnography, "none of the reported medical history and/or anatomical parameters alone, or in combination, could be used to distinguish patients with obstructive sleep apnea syndrome from snoring patients," wrote lead researcher Dr. Alfred in the February issue of Archives of Otolaryngology-Head & Neck Surgery.

"In our opinion, all patients seeking treatment for snoring should be screened overnight using a device measuring at least oxygen saturation and airflow," his team concluded.

More information

To find out more about the causes and treatment of sleep apnea, go to the American Academy of Family Physicians.