Epworth Sleepiness Scale Calculator

How does this Epworth Sleepiness Scale calculator work?

This is a scale that aims to evaluate daytime sleepiness and is used mainly in diagnosing sleep disorders. As the name states, it has been introduced in 1991 in the Epworth Hospital in Melbourne by Dr Murray Johns.

The Epworth Sleepiness Scale calculator comprises of 8 multiple choice questions, each with the same scale of 4 answers. It is the standard world wide method of sleepiness controlled assessment and evaluation of sleep-wake health status.

The assessor is instructed to take the patient’s name, gender and age and note the date of the test and to ask the patient to rate the probability of falling asleep in different day to day situations, on the scale from most probable to least probable, from 0 to 3:

■ Would never doze (0 points);

■ Slight chance of dozing (1 point);

■ Moderate chance of dozing (2 points);

■ High chance of dozing (3 points);

Given that patients are asked to evaluate the chances of dozing of rather than number the moments when they have dozed in the situations given, the test is highly subjective and reflective. Usually the test can be answered in less that 4 minutes.

The items used in the Epworth Sleepiness Scale are as follows:

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.

The scale is said to help in indentifying specific sleep disorders however, specialist diagnostic is still required. Similar assessment, but focused more on the quality of sleep is included in the Pittsburgh Sleep Quality Index.

What the ESS tries to measure is the ASP (Average Sleep Propensity) in various daily activities. What is important to note is that ASP is not synonymous with tiredness and fatigue. ASP is classified as mild, moderate and severe, with mild, moderate stages not meaning that the patient is prone to falling asleep during the day necessary but might have a bigger propensity to such situations than his peers.

Also, it is important for the subject and assessor to make a clear distinction between the usual sleep deprivation due to not enough sleep at night and sleep cycle troubles like an increase in the sleep deprivation that is not related to the current sleep hours, phenomenon called “sleep debt”.

ESS score interpretation

Given that each of the choices in the eight questions is rated from 0 to 3, the results range from 0 to 24. Scores below 9 are considered to be in the normal range sleep propensity, scores between 10 and 24 on the other side indicate that specialist diagnosis and treatment might be required.

The total result provides an insight into the general level of sleepiness the subject confronts with during the day but doesn’t necessarily distinguish between the underlying factors.

This sleepiness score is also used in evaluating the risk for sleep apnea with the range 11 – 15 indicating the probability of an additional diagnosis of mild to moderate sleep apnea and scores above 16 the possibility of severe sleep apnea and/or narcolepsy.

In patients with obstructive sleep apnea syndrome ESS scores were discovered to be correlated with the respiratory disturbance index and the minimum SaO₂ recorded overnight.

In terms of validation, with a 100% specificity and 93.5% sensitivity, the most research has been done in obstructive sleep apnea but a certain degree of success is also expected in identifying idiopathic hypersomnia and narcolepsy.

References

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

2) Johns MW. (2000) 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; 9(1):5-11.

3) Hardinge FM, Pitson DJ, Stradling JR. (1995) Use of the Epworth Sleepiness Scale to demonstrate response to treatment with nasal continuous positive airways pressure in patients with obstructive sleep apnea. Respir Med; 89(9):617-20.