A device has been developed which is placed under the mattress, thereby escaping contact with patient, which enables monitoring of sleep activity and has been shown in some studies to provide an estimate of the frequency of sleep disordered breathing. If the estimates of sleep disordered breathing from this new device are medically equivalent to current excepted home sleep apnea test devices within clinically important ranges of sleep disordered breathing, it may have several benefits. This study is designed to help answer several important clinical questions, namely, is the new device clinically equivalent to an established HSAT device for patients who have at least moderately severe OSA, and what is the effect of multiple nights on classification of severity and presence of OSA.

The design will be a prospective test of two diagnostic testing strategies. The tests will take place in the same patient concurrently, so the patient's results from one test will serve as the comparator with the other test device. No randomization or blinding is needed.

Patients will be recruited from the Mayo Clinic Center for Sleep Medicine (and another sleep center with enriched racial variety). Consecutive patients in whom the clinician has ordered a WatchPAT™ will be potential candidates for an opportunity to participate in the study. Patients will be made aware of the trial by invitation from members of the healthcare team. Interested patients will be evaluated according to the inclusion and exclusion criteria.

Inclusion Criteria:

Clinician suspects of having OSA due to presence of any:

• STOP-BANG ≥ 3,
• overnight oximetry with ODI ≥ 5,
• STOP-BANG≥ 2 and one or more of: disrupted sleep, cognitive complaints, paroxysmal or prior atrial-fibrillation (now in NSR), stroke, TIA
• Has a smartphone capable of running both Withings and Itamar's app
• Stable sleeping quarters and schedule (i.e., no overnight shifts) for at least 7 days
• Domicile has capable wireless internet service

Exclusion Criteria:

• Uses short-acting nitrates within 3 hours of the study
• Has a permanent pacemaker
• Atrial fibrillation or sustained supraventricular arrhythmias
• Known congestive heart failure Class ≥ 1, or known LVEF< 45%
• Sustained hypoxemia or hypoventilation (results of RA daytime ABG show SaO2<90% or PaCO2>45 mmHg, or overnight oximetry shows mean SaO2<90%.)
• Advanced pulmonary disease (COPD GOLD stage ≥ II , pulmonary fibrosis with GAP ≥ 1 or significant dyspnea on exertion

Diagnosis of OSA