The purpose of this randomized prospective study is to compare the efficacy of two approaches to initiate Positive Airway Pressure (PAP) treatment in patients diagnosed as having obstructive sleep apnea (OSA) by portable monitoring (PM) (limited sleep study). One pathway involves attended Continuous Positive Airway Pressure (CPAP) titration by PSG (full attended sleep study) followed by CPAP treatment. The other pathway involves treatment with auto-adjusting positive airway pressure (APAP)(without a titration). Study Aims: Compare PAP adherence, improvement in subjective sleepiness (Epworth Sleepiness Scale), reaction time (Psychomotor vigilance test), quality of life by the Functional Outcomes of Sleep Questionnaire (FOSQ), and PAP satisfaction (PAP satisfaction questionnaire) between the two study arms.

RESEARCH PLAN: All patients being evaluated for possible OSA are required to attend a Sleep Education and Evaluation Class before having a sleep study. At this class they receive information on sleep apnea, PAP treatment, and the types of sleep studies. They also complete a sleep questionnaire to identify co-existing sleep disorders and important co-morbid medical conditions. Screening of the sleep questionnaire and the patient's medical record is part of routine care to identify patients needing a diagnostic PSG and/or an attended titration. At the end of the class, participation in the current study will be offered the patients. Those signifying interest in being part of the research study and meeting inclusion and exclusion criteria will be contacted to participate in the study. Once they sign an informed consent they will be randomized to one of the two clinical pathways.

METHODS: Study visits:

Before informed consent (routine clinical care)

1. Sleep Education and Evaluation Class (education about OSA, sleep studies, and OSA treatment). Patients complete screening sleep and medical history questionnaires.
2. Determination of patient interest in participating in the current study and review of inclusion/exclusion criteria

After informed consent

1. PM study
2. Randomization if the Portable monitoring (PM) study is diagnostic of OSA. If not, the patient will be offered a diagnostic PSG. If this is positive, they will have APAP treatment. If both the PM and PSG are negative for OSA the patient exits the study but will be followed in sleep clinic.
3. PSG for CPAP titration (PSG arm only).
4. CPAP/APAP setup - patient fills out Epworth Sleepiness Scale (ESS) and Functional Outcomes of Sleep Questionnaire (FOSQ). The same Research coordinator/Respiratory therapist will setup the units, fit masks, and instruct the patients on the use of their device. Patients being treated with CPAP or APAP will be in separate classes.
5. Telephone contact within 7 days of setup with early intervention for PAP problems if needed.
6. Clinic visit 6 weeks after starting treatment: download objective adherence, ESS, FOSQ, and PAP satisfaction questionnaire.

Inclusion Criteria:

• OSA, Apnea-hypopnea index > 5/hour

Exclusion Criteria:

• Prior CPAP
• Uncontrolled Depression
• Moderate to Severe chronic obstructive pulmonary disease (COPD)
• Hypoventilation
• Average estimated nightly total sleep time < 4 hours
• Shift work
• Unstable depression
• Upper airway surgery
• Uncontrolled Restless legs syndrome (RLS), narcolepsy
• Use of supplemental oxygen
• Severe congestive heart failure
• Use of nightly potent narcotics
• Severe obesity (BMI > 40)