Inclusion Criteria:  Adults (> 18 ans) Polysomnography planned for OSA assessment RPL known or not, suspected or not Affiliation to a social security scheme or beneficiary of such a scheme Patient having signed the free and informed consent  Exclusion Criteria:  Minors Smoking, alcoholism, chronic or serious disabling pathology Medical history of upper aerodigestive tract cancer, radiotherapy Recent infection of upper aerodigestive tract, chronic rhinosinusitis Permanent nasal obstruction Active allergy Non-obstructive SAS (central) Patient under anti-secretory treatment (IPP) during the 8 days preceding the Restech associated with the PSG Refusal to participate in the study Protected patients: Adults under guardianship, guardianship or other legal protection, deprived of liberty by judicial or administrative decision Pregnant, breastfeeding or parturient Hospitalized without consent