Evaluation of excessive daytime sleepiness.

Excessive Daytime Sleepiness (EDS) is a difficult clinical problem, which is often indicative of a serious underlying physiologic condition. EDS is associated with automobile accidents, work-related injury, and increased use of the health care system, but it appears to be under-appreciated despite its common occurrence. There are many causes of EDS, ranging from insufficient sleep or inadequate sleep hygiene to drug effects and serious medical conditions. Assessment of EDS should begin with a detailed clinical history, and may also include self-rated instruments and ultimately physiologic tests to measure propensity to fall asleep or stay awake. Ultimately, evaluation in the sleep laboratory is often required in order to arrive at an accurate diagnosis and an appropriate therapeutic recommendation.