The quality of CPAP titration is graded as follows: optimal (obstructive AHI ≤ 5/h, supine REM sleep on the treatment pressure; desaturation index≤ 5/h of sleep), good (obstructive AHI < 10/h, REM sleep on the treatment pressure, desaturation index≤ 10/h), adequate (AHI < 10/h, supine NREM sleep on the treatment pressure, desaturation index≤ 10/h). A persisting central AHI < 5 will be tolerated. If none of these criteria are met, patients will be referred to conventional attended CPAP polysomnograpy and excluded from the study.