[Polysomnography (PSG) for studying sleep disorders].

BACKGROUND: Sleeping problems are very common, and many patients need a comprehensive assessment with polysomnography, possibly followed by a sleep latency test. These methods and indications for the tests are described below.

METHOD: The article is based on the authors' own literature archives, clinical experience and Retningslinjer for metoder i klinisk neurofysiologi [Guidelines for methodology in clinical neurophysiology]

RESULTS: Polysomnography involves monitoring sleep through the course of one night and scoring the stages of sleep on the basis of EEG activity, eye movements and muscular tension. Also recorded are inter alia respiratory variables. Polysomnography followed by a multiple sleep latency test (MSLT) is used when narcolepsy or excessive daytime sleepiness is suspected. If parasomnia is suspected, the examination should include polysomnography, preferably with video recording. If sleep apnoea is suspected in adults, respiratory polygraphy is often sufficient. As a rule, polysomnography is preferable to respiratory polygraphy for studying sleep disorders in children.

INTERPRETATION: Sleep disorders take many forms and are dealt with by many different specialities. Good cooperation between the different specialities is necessary to ensure an optimal result for the patients.