Functional Outcomes of Sleep Questionnaire (FOSQ) is a 30-item disease-specific measure to assess the impact of excessive daytime sleepiness on activities of daily living. It includes five subscales: activity level, vigilance, intimacy and sexual relationships, general productivity, and social outcomes. The potential range for each subscale is 1-4, with a total score of 5-20. Higher scores on the FOSQ indicate better daily functioning. The FOSQ has established content validity, test-retest reliability (0.90), internal consistency (0.96), and concurrent validity with standardized generic measures of functional status.

Quality of life will be measured by the 12-item Short Form Health Survey (SF-12). The SF-12 is a validated short form survey with 12 questions selected from the SF-36 Health Survey. The questions are scored to provide evaluations into mental and physical functioning and overall health-related quality of life.

The Dyadic Coping Inventory (DCI) is a 37-item questionnaire that assesses stress communication and dyadic coping as perceived by each partner about his or her own coping, each partner's perception of the other's coping, and each partner's view of how they cope as a couple on a scale from 1 (very rarely) to 5 (very often). There are four subscales measuring types of dyadic coping: delegated, supportive, stress communication, and negative dyadic coping.

Epworth Sleepiness Scale (ESS) includes items about the likelihood of falling asleep in eight soporific situations. The ESS significantly correlates with the frequency of apneic episodes and is a clinical and research standard in the assessment of daytime sleepiness. It has high test-retest reliability (0.82) and internal consistency (0.88).

Patient-Reported Outcomes Information System (PROMIS®) assesses self-reported perceptions of sleep quality, sleep depth, and restoration associated with sleep.The PROMIS Sleep-Related Impairment focuses on self- reported perceptions of alertness, sleepiness, and tiredness during usual waking hours, and the perceived functional impairments during wakefulness associated with sleep problems or impaired alertness. Both tools can readily discriminate patient and control groups, and are sensitive to treatment.

A brief questionnaire with 6 validated items will be used, including three subscales: pressure (asked about using CPAP, tried to persuade you to use CPAP, dropped hints about using CPAP), collaboration (helped solve a problem with CPAP, helped with the CPAP machine), and support (felt supported for using CPAP) on a scale from 1 (not at all) to 5 (extreme). We have used paired versions (one for patient and one for partner) for dyadic evaluation.