Epworth sleepiness scale

The Epworth sleepiness scale is a short self-rating questionnaire that asks one simple question in eight everyday flavors: how likely are you to doze off, not just feel tired, in this situation? The eight scenarios range from sitting and reading or watching television to being a passenger in a car, lying down to rest in the afternoon, sitting and talking, and stopped briefly in traffic.

For each situation the person rates the chance of dozing from 0 (would never doze) to 3 (high chance of dozing), and the eight scores are summed to a total from 0 to 24. Conventionally, a score above 10 suggests excessive daytime sleepiness worth investigating, with higher scores indicating greater sleep propensity. The questionnaire captures the recent habitual tendency to fall asleep, not how a person feels at one moment.

Its great virtues are speed and simplicity: it takes a couple of minutes, needs no equipment, and gives clinicians a standardized, repeatable number to screen for sleepiness, gauge its impact, and follow response to treatments such as CPAP. It is widely used in sleep clinics and research as a practical measure of subjective daytime sleepiness.

Its limits are equally important. The Epworth scale is subjective and self-reported, so it can be under- or over-stated, and it correlates only loosely with objective measures and with the apnea–hypopnea index. A normal score does not exclude sleep apnea, and a high score does not by itself diagnose it; the questionnaire complements, but never replaces, a proper sleep evaluation.