Polysomnography, commonly abbreviated as PSG, is an electrophysiologic monitoring technique used to collect the comprehensive information needed to identify human sleep and wake states. Multiple physiologic systems are also evaluated with PSG for signs of sleep disorders. PSG may be used for research or clinically, to help narrow a diagnosis or evaluate the effect of a pharmacologic or behavioral intervention. Abbreviated [Page 2590]versions of PSG may be used for specific diagnostic purposes during the daytime (e.g., Maintenance of Wakefulness Test or Multiple Sleep Latency Test), but the focus here is on nocturnal PSG. This entry presents a brief history of PSG development, its procedural details, and the valuable information (data and metrics) that PSG provides.

During PSG, a person is instrumented with noninvasive sensors to evaluate ...