Therapy Adherence of APAP Therapy Initiation in Sleep-lab Versus at Home

Inclusion Criteria: * written informed consent from patients after verbally and written informing * Age between 18 and 80 Years * obstructive sleep apnea syndrome (OSAS) with an AHI \> 15/h and without previous therapy Exclusion Criteria: * Intolerance to wear the PAP therapy mask * sleep breathing disorders (SBD) with central apneas \> 20% and other sleep disorders * disabilities who prevents the wear of a therapy mask * initiated PAP therapy * pre-treatment of OSAS incl. UPPP (uvulo palato pharyngo plasty) * modified Mallampati Score T3 and T4 * participation on clinical studies 4 weeks before start of the study * known or acute psychiatric/neurological or psychological disorders, who impairs the compliance to take part of the study. * chronical or new clinically significant pneumological or cardiovascular disease (exception: effectively therapies of hypertension, cardiac arrhythmia and coronal cardiac disease) * acute internistic disease * neuromuscular disease * condition after Apoplexy * oncological disease in recent 5 years * drug/alcohol consumption * consumption of von psychotropic drugs, hypnotics and other drugs who are able to influence the sleep/wake cycle