What is the interpretation of the Epworth Sleepiness Scale (ESS)?

From the Guidelines

The Epworth Sleepiness Scale (ESS) is interpreted based on a total score ranging from 0 to 24, with higher scores indicating greater daytime sleepiness, and a score of 11 or higher suggests moderate to severe sleepiness that may require medical attention. The ESS is a self-reported questionnaire involving eight questions to assess the propensity for daytime sleepiness or dozing 1. A score of 0-5 is considered normal daytime sleepiness, 6-10 indicates mild sleepiness, 11-12 suggests moderate sleepiness, and 13-24 represents severe sleepiness that may require medical attention.

Key Points to Consider

• The ESS works by asking individuals to rate their likelihood of dozing off in eight different everyday situations on a scale of 0-3, with these ratings then summed to create the total score.
• This self-assessment tool is valuable because excessive daytime sleepiness can impact quality of life, work performance, and safety, particularly when driving or operating machinery, as highlighted in the American Thoracic Society clinical practice guideline 1.
• However, the ESS should be considered alongside other clinical information, as it's a subjective measure and doesn't diagnose specific sleep disorders on its own, with studies indicating a large number of false negative results limiting its utility for the diagnosis of obstructive sleep apnea (OSA) 1.
• The ESS has been evaluated against polysomnography (PSG) in several studies, showing a range of sensitivity and specificity, but its performance is limited by false negative results 1.

Clinical Implications

• If an individual scores 11 or higher on the ESS, they should consult a healthcare provider as this level of sleepiness could indicate a sleep disorder such as obstructive sleep apnea, narcolepsy, or idiopathic hypersomnia.
• The ESS is a useful tool for assessing daytime sleepiness, but it should be used in conjunction with other diagnostic tests and clinical evaluations to determine the underlying cause of sleepiness.

From the FDA Drug Label

In addition, for entry into these studies, all patients were required to have excessive sleepiness as demonstrated by a score ≥10 on the Epworth Sleepiness Scale (ESS), despite treatment with continuous positive airway pressure (CPAP). The primary measure of effectiveness was the change from baseline on the ESS at final visit. The baseline ESS scores for the modafinil tablets and placebo groups were 14. 2 and 14.4, respectively. At week 4, the ESS was reduced by 4.6 in the modafinil tablets group and by 2.0 in the placebo group, a difference that was statistically significant.

The Epworth Sleepiness Scale (ESS) is used to measure excessive daytime sleepiness. A score of ≥10 indicates excessive sleepiness. The scale is used to assess the effectiveness of treatments for sleep disorders, such as modafinil tablets.

• A higher score on the ESS indicates greater daytime sleepiness.
• A reduction in ESS score indicates an improvement in wakefulness. 2

From the Research

Epworth Sleepiness Scale Interpretation

The Epworth Sleepiness Scale (ESS) is a widely used tool to measure sleepiness, but its interpretation can be complex.

• The ESS scores can vary considerably within individual patients, which may limit its clinical use 3.
• Studies have shown that the test-retest reliability of the ESS is substantial when scores are classified as either normal or sleepy, with a Cohen's kappa of 0.67 3.
• However, the reliability of the ESS can be limited when used to make individual-level comparisons, such as the effect of therapeutic interventions, due to the wide distribution of between-score differences 4.
• The intraclass correlation coefficient for test-retest reliability of the ESS has been reported to be 0.73, indicating moderate statistical reliability 4.
• Despite this, the 95% limits of agreement for the ESS scores have been found to be wide, ranging from -8.5 to +10.6, and an absolute difference in scores of at least 3 has been observed in 56% of participants 4.
• The ESS scores can be influenced by various factors, but no demographic or clinical variables have been identified as contributing to the intra-individual variability 3.