A single question as a sleepiness screening tool.

Study Objectives: A single subjective question may be an effective screening tool for excessive daytime sleepiness. This study sought to determine whether the following single question about sleepiness can measure subjective sleepiness comparably to the Epworth Sleepiness Scale (ESS): "Please measure your sleepiness on a typical day: (0 = none, 10 is highest)." The relationship between this question and objective sleepiness as measured by the MSLT was also evaluated.