Continuous Positive Airway Pressure, Arousability and Links to Mechanisms in Obstructive Sleep Apnea

Inclusion Criteria:

* Able to provide informed consent.
* Clinically confirmed new diagnosis of OSA:

  1. Polysomnography AHI ≥ 10 per hour of sleep and/or
  2. Home sleep apnea testing, respiratory even index, REI ≥ 10 per hour of recording

Exclusion Criteria:

* Known non-OSA related conditions associated with sleep-disordered breathing (e.g., a central disorder of hypersomnolence, neurological, neuromuscular, or pulmonary disorder)
* Use of sleep-inducing medications (e.g., other non-benzodiazepine sedative hypnotic-drugs \[e.g., zoldpidem\], benzodiazepines, non-selective antihistamines, trazodone, opiates, barbituates)
* Known hypersensitivity reaction to eszopiclone
* Contraindications to its use based on medical history or function (e.g., dizziness at baseline or established mobility problems or imbalance)
* History of complex sleep behaviors (e.g., NREM or REM parasomnias)
* Concomitant use of ≥ 2 servings of alcohol per night or other CNS depressant for 2 weeks prior or throughout the study
* Sleep opportunity of less than 7 hours
* Severe active depression or other mental health disorders (e.g., schizophrenia, bipolar disorder, personality disorder).
* History of sleep-walking, sleep-driving, and engaging in other activities while not fully awake
* History of motor vehicle accidents related to sleepiness and/or motor vehicle "near misses" (e.g. sleepiness during driving or lane changes)
* Severe hepatic impairment (liver function tests 2 X the upper limit of normal)
* Unstable medical condition (e.g., decompensated heart failure, end-stage chronic obstructive pulmonary disease, end-stage renal disease)
* Females of childbearing potential who are pregnant, breastfeeding, or intend to become pregnant, and women who are in the process of egg donation .