The perception of sleep as a function of the level of daytime sleepiness among patients with obstructive sleep apnea.

Subjective estimates of sleep onset among patients with a variety of sleep disorders have been shown to be inaccurate. This inability in perceiving sleep onset is potentially dangerous for this population, in particular, for individuals who are required to drive long distances or operate heavy machinery as part of their daily activities. This study evaluated the perception of sleep among 237 consecutive patients diagnosed with obstructive sleep apnea. Patients completed an overnight sleep-laboratory evaluation followed by an objective evaluation of sleep propensity. The latter was done using the Multiple Sleep Latency Test (MSLT). Patients with an accurate perception of having slept on the MSLT were found to have shorter sleep latencies when compared with those with an inaccurate perception of their sleep. The results of this study suggest that the rapidity with which sleep is manifested is an important contributor to the accurate perception of sleep.