Diagnosis of sleep apnoea: some critical issues.

Rather than describing a method for determining which patients should be labelled as having a disease, sleep apnoea, this review describes assessment as a process for deciding whom to investigate, what degree of sleep apnoea they have, how important their symptoms are, whether symptoms are likely attributable to sleep apnoea, and what sort of treatment to offer, if any. Beginning with identifying patients at risk and use of clinical prediction rules, the review covers (i) measurement and implications of the apnoeahypopnoea index; (ii) distinguishing central from obstructive apnoeas; (iii) significance of associated periodic limb movements; (iv) the controversy about the use of portable monitors instead of laboratory polysomnography; (v) evaluation of symptoms associated with sleep apnoea; and (vi) the important role of trials of treatment.