Diagnostic techniques in obstructive sleep apnea.

Only in the last 25 years has sleep apnea been recognized as a very common disorder and important cause of mortality. Overnight, attended polysomnography remains the reference diagnostic tool for sleep apnea, although the technology for diagnosis continues to evolve rapidly. In many instances, screening and ambulatory monitoring devices can provide similar, clinically relevant information, but larger validation studies including long-term clinical outcomes are necessary.