Epworth Sleepiness Scales
The ESS is an 8-item self-administered questionnaire that provides a measure of an individual’s general level of daytime sleepiness.25 Respondents are asked to rate their usual chances of dozing off or falling asleep on a 4-point scale (0–3) in 8 distinct situations or activities that most people engage in during their daily lives but not necessarily every day. Potential situations include “sitting and reading,” “watching TV,” and “lying down to rest in the afternoon when circumstances permit.” The total ESS score is the sum of 8-item scores ranging from 0 to 24, with higher scores indicating higher levels of daytime sleepiness. Completing the ESS generally takes 2 to 3 minutes. Total ESS scores are reliable in a test-retest sense over a period of months (ρ = 0.82; n = 87; P < .001). There is a high level of internal consistency within the ESS as demonstrated by Cronbach α statistic ranging from 0.74 to 0.88 in 4 different groups of subjects. Patients were asked to complete an ESS each week beginning on the fifth day of inpatient treatment.