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.

Methods: 303 subjects completed a sleep questionnaire, MSLT, and ESS within 2 months. ROC (receiver-operator characteristic) curves and contingency tables using Fisher's exact test were made using GraphPad Prism software.

Results: ESS and SS scores showed a significant association at all SS score cut-points. ESS and MSL showed significant associations only at ESS scores 11, 12, and 18. SS scores were significantly related to the MSL only in non-sleep apneics at SS scores 2, 5, 6, and 8, and in sleep apneics at SS score 9. ROC analysis showed the SS could distinguish subjects with an ESS > or = 11 from those with an ESS < 11 (area = 0.71, p < 0.0001).

Conclusions: Neither the SS nor the ESS substitutes for the MSLT, which measures objective sleepiness and is not an appropriate screening tool. SS scores < or = 2 and > or = 9 reliably predict normal and abnormal ESS scores respectively. Since the ESS is not commonly used in non-sleep specialized practices, the SS may serve as a useful screening tool for patients with disorders of sleepiness.