 Many Veterans suffer from sleep disordered breathing with a high prevalence of undiagnosed obstructive sleep apnea. One test that can be effective in the diagnosis of sleep apnea is the polysomnogram PSG. Split-night PSG consists of a diagnostic phase in the first half of the night and a continuous positive airway pressure titration CPAP in the second half of the night. CPAP is the standard, most effective therapy for obstructive sleep apnea. Due to the unfamiliar sleep environment of the laboratory and instrumentation that must be used application of electroencephalogram leads, patients are frequently not able to sleep adequately. In these cases, the PSG must be repeated. Oral hypnotic agents are often used as a pre-medication to increase the yield of PSG in an attempt to decrease the need for repeat studies. 