The Epworth Sleepiness Scale (ESS) is a scale intended to measure daytime sleepiness that is measured by use of a very short questionnaire. This can be helpful in diagnosing sleep disorders. It was introduced in 1991 by Dr Murray Johns of Epworth Hospital in Melbourne, Australia.
The questionnaire asks the subject to rate his or her probability of falling asleep on a scale of increasing probability from 0 to 3 in eight different situations.The scores for the eight questions are added to obtain a single number. A number in the range 0–9 is considered to be normal while a number in the range 10–24 is considered to indicate that specialist medical advice should be recommended.