Sleep studies. Current techniques and future trends.

Diagnosis of obstructive sleep apnea has been termed a laboratory diagnosis rather than a clinical diagnosis because one may not be able to make the diagnosis based on the history and physical examination alone. The polysomnogram was developed to give clinicians and researchers objective data on physiologic events occurring during the patient's sleep. From this, obstructive breathing patterns can be diagnosed and if pathologic, appropriate treatment can be instituted. Although the polysomnogram has been the gold standard for diagnosis for more than two decades, it is an expensive and time-consuming procedure. Current technologies for polysomnogram are reviewed, as well as proposals for alternatives that may be more cost and time effective.