Epworth Sleepiness Scale

Diagnoses sleep disorders such as sleep apnea or narcolepsy by evaluating sleep related behaviour.

Below the tool, there is in depth information about the ESS scale, its usage and interpretation.

The Epworth sleepiness scale consists of 8 multiple choice questions that evaluate sleepiness, especially during daytime activities.

It is used in the diagnosis of sleeping disorders, sleep apnea and narcolepsy.

Each of the 8 questions in the ESS is accompanied by the same scale of 4 answers, scored from 0 to 3, where 0 means no chance to doze and 3 means high chance of dozing.

Results range from 0 to 24 and the threshold between normal range sleep propensity and need for diagnosis is situated at 9 points.

The original study involved 180 subjects, 30 with no sleep disorders as controls and 150 with a range of sleep disorders. The scale has been validated with a 100% specificity and 93.5% sensitivity.

Instruction: Rate how likely you are to fall asleep in the following situations:

Sitting and reading


Watching TV


Sitting, inactive in a public place


As a passenger in a car for an hour without a break


Lying down to rest in the afternoon when circumstances allow


Sitting and talking to someone


Sitting quietly after lunch without alcohol


In a car, while stopped for a few minutes in traffic

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Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.

Epworth Sleepiness Scale - a self-administered questionnaire

The ESS was introduced at the Epworth Hospital in Melbourne in 1990 by Dr Murray Johns. It is a self-administered questionnaire (usually less than 4 minutes to complete) that is aimed at measuring daytime sleepiness.

It focuses on measuring the Average Sleep Propensity (ASP) in selected types of day to day activities. ASP has three stages of different severity: mild, moderate and severe, that are used to quantify the propensity of falling asleep.


Scale items

The Epworth Sleepiness Scale calculator consists of the following daily situations, which the patient is asked about:

1. Sitting and reading;

2. Watching TV;

3. Sitting, inactive in a public place;

4. As a passenger in a car for an hour without a break;

5. Lying down to rest in the afternoon when circumstances allow;

6. Sitting and talking to someone;

7. Sitting quietly after lunch without alcohol;

8. In a car, while stopped for a few minutes in traffic.

During the evaluation, it is very important for the assessor to differentiate between normal sleep deprivation (caused by not enough sleep at night) and sleep cycle issues such as sleep debt.


Scoring method

The patients are asked to rate their chances of dozing during the above situations by choosing one of the answers on the scale:

■ Would never doze (0 points);

■ Slight chance of dozing (1 point);

■ Moderate chance of dozing (2 points);

■ High chance of dozing (3 points);

Based on the answer choice, each question is awarded a number of points, ranging between 0 and 3. The final score is calculated by summing the points and will be somewhere between 0 and 24.



A threshold at 9 points has been established which means that scores below 9 are considered in the normal range of sleep propensity while scores above 0 may indicate the presence of one or more sleep disturbances.

Therefore, scores between 10 and 24 come with the recommendation for further diagnosis and treatment.

When analysing the ESS results and taking in consideration the risk for sleep apnea, results between 11 and 15 are associated with the probability of an additional diagnosis of mild to moderate sleep apnea. Scores above 16 are associated with probability of additional diagnosis of severe sleep apnea and/or narcolepsy.


About the original study

180 subjects have rated their chances of dozing off or falling asleep, 30 of whom were chosen as control group and 150 already diagnosed with a range of sleeping disorders (including obstructive sleep apnea syndrome, narcolepsy and idiopathic hypersomnia).

The scale has a 100% specificity and 93.5% sensitivity.

In patients with obstructive sleep apnea syndrome, the ESS correlates with the respiratory disturbance index and the minimum SaO2 recorded overnight.

ESS scores were also correlated with sleep latency testing and overnight polysomnography results.

Although the scale is helpful in identifying patients who suffer from sleep disorders, the evaluation needs to be continued with specialist diagnosis in highlighted cases.

One criticism of the model is the fact that it only provides an insight into the level of sleepiness the patient undergoes and does not differentiate between underlying factors.

Some criticize the model because of the subjectivisms of the patient who may exaggerate or minimize the effects of the sleep disorder.

Dr Murray Johns, the creator of the ESS has run the Epworth Sleep Centre and was the first person to be awarded a PhD in sleep medicine in Australia. He has also pioneered the Optalert technology for monitoring drowsiness in active people.


Another sleep evaluation

The Pittsburgh Sleep Quality Index (PSQI) is a similar questionnaire to the ESS, in the sense that it can be self-administered and offers information about the possible existence of any sleep disorders.

It looks at seven areas of sleep: subjective quality, latency, duration, efficiency, disturbances, use of medication and daytime dysfunction. Each of the 19 items is weighted on a scale from 0 to 3.


Original reference

Johns MW. A new method for measuring daytime sleepiness: The Epworth sleepiness scale. Sleep. 1991; 14(6):540-5.

Validation study

Rosales-Mayor E, Rey de Castro J, Huayanay L, Zagaceta K. Validation and modification of the Epworth Sleepiness Scale in Peruvian population. Sleep Breath. 2012; 16(1):59-69.

Other references

1. Johns MW. Reliability and factor analysis of the Epworth Sleepiness Scale. Sleep. 1992; 15(4):376-81.

2. Johns MW. Sensitivity and specificity of the multiple sleep latency test (MSLT), the maintenance of wakefulness test and the Epworth sleepiness scale: failure of the MSLT as a gold standard. J Sleep Res. 2000; 9(1):5-11.

3. Wise MS. Objective measures of sleepiness and wakefulness: application to the real world? J Clin Neurophysiol. 2006; 23(1):39-49.

Specialty: Sleep Medicine

System: Nervous

Objective: Evaluation

Type: Scale

No. Of Items: 8

Year Of Study: 1990

Abbreviation: ESS

Article By: Denise Nedea

Published On: March 16, 2017 · 07:38 PM

Last Checked: March 16, 2017

Next Review: March 10, 2023