S104 Polysomnography: From the basis to the information content

Objectives and methods Polysomnography (PSG) is the widely used diagnostic method of sleep medicine. The recorded parameters are the EEG, eye movements, muscle tone, different cardiorespiratory parameters (nasal air flow, breathing effort, ECG, oxygen saturation, etc.), body position, snoring and limb movements. On the base of the recorded parameters the alteration of the sleep architecture and background pathology can be determined. The polysomnographic abnormalities are described in the guidelines. The main challenge of PSG is the interpretation of these result. Here we present the basic principles and interpretation aspects of polysomnography. Results The two most important background pathologies - affecting the sleep architecture - are the breathing abnormalities and movement events. The patterns of respiratorical abnormalities can define different clinical pictures. The same movement event can be the consequence of many different background pathologies (from breathing related events to periodic limb movement disorder or narcolepsy). Discussion Interpretation of different polysomnographic abnormalities and patterns are more than a simple count of the pathological events. Different pathological backgrounds can lead to the same basic abnormalities. The clinical information about the sleep disorders will help to improve the interpretation of the polysomnographic abnormalities. Beside the clinical information, the interpretation of the polysomnographic recording depends on the reliability of the scoring and staging of the pathological events. Conclusions Clinical information is essential for the appropriate interpretation of the polysomnographic results. Significance Clinical information based interpretation of the PSG.