ABSTRACT
Excessive daytime sleepiness is the most common complaint heard in sleep disorder centers. It refers to sleepiness that occurs during a time when the individual would be expected to be awake. The measurement of excessive daytime sleepiness is important for the evaluation and diagnosis of some sleep disorders and for evaluating the response to treatment. In addition, the measurement of alertness has also become important for evaluating response to treatment and fitness to return to work. Both objective and subjective tests have been developed to measure sleepiness and alertness, and each has advantages and limitations.
