Event scoring in polysomnography: scoring arousals, respiratory events, and leg movements.

Polysomnographic events comprise a wide variety of phenomena,including episodes of apnea, episodes of hypopnea, leg movements, transient central nervous system arousals, and eye movements. The process of event scoring involves pattern recognition and provides a description of potentially pathophysiologic activity occurring during sleep. The rules for scoring sleep-related events continue to be developed. The rules are precise and must be followed with extreme care. When the polysomnogram is interpreted,the report must include a summary of event scoring and clinical correlation to the sleep complaint. Arousals, periodic limb movements, and respiratory events are significant because they represent pathophysiologies on which final diagnosis largely depends.