The use of sleep studies in neurologic practice.

Sleep medicine is a multidisciplinary specialty that is rapidly advancing with exciting new discoveries. Some sleep disorders are diagnosed by clinical history alone, but others such as sleep apnea, narcolepsy, periodic limb movement disorder, parasomnias, and nocturnal seizures (conditions that will be addressed by other articles in this issue) usually require evaluation in the sleep laboratory. Sleep studies are used for diagnostic purposes, to assess disease severity, and to evaluate treatment efficacy. Routine sleep testing can be tailored to answer the specific clinical question at hand. In this article, the authors review the most commonly performed sleep tests in the sleep laboratory and their indications, interpretation, and limitations. These include the polysomnogram (PSG), the Multiple Sleep Latency Test (MSLT), the Maintenance of Wakefulness Test (MWT), and actigraphy. The accurate interpretation of these studies requires a comprehensive sleep and medical history.