Table 2.

Diagnostic instruments for the different categories of sleep-related breathing disorders

	Questionnaires	Performance and vigilance tests	1–3-channel polygraphy	4–6-channel polygraphy	Polysomnography
Obstructive sleep apnea	(+)	(+)	(+)	+	+
Central sleep apnea	(+)		(+)	(+)	+
Sleep-related hypoventilation				(+)	+
Sleep-related hypoxemia				(+)	+

+ use recommended, (+) use possible under particular conditions, no entry the method is neither recommended nor rejected, i. e., there is no evidence for the method or it is not possible or it is economically nonviable