 Numerous data is available on the effects of premedication with oral short-acting hypnotics on PSG quality and efficacy of CPAP titration. In one study, eszopiclone, a nonbenzodiazepine gaba-receptor agonist short-acting hypnotic, has been shown to improve PSG quality and CPAP titration. Another short-acting hypnotic, ramelteon, was recently approved by FDA but the effects of ramelteon in improving PSG quality and efficacy of CPAP titration are unclear. The advantage of ramelteon over eszopiclone is the lack of drug dependency or abuse potential. This study aims to evaluate the efficacy of ramelteon compared to eszopiclone when administered prior to split-night PSG and CPAP titration. 