Quantifying the level of daytime sleepiness (somnolence) in adults.
Initial screening for Obstructive Sleep Apnea (OSA) or Narcolepsy.
Monitoring the effectiveness of CPAP or pharmacotherapy for sleep disorders.
Evaluating the risk of drowsy driving or occupational accidents.
Section 2
Formula & Logic
Scoring Component
The ESS assesses the "chance of dozing" in 8 common daily situations. Each situation is rated from 0 (would never doze) to 3 (high chance of dozing).
Severity Thresholds
Score 0–10
Normal range
Score 11–12
Mild excessive sleepiness
Score 13–15
Moderate excessive sleepiness
Score 16–24
Severe excessive sleepiness
Section 3
Pearls/Pitfalls
Sleepiness vs. Tiredness
The ESS measures "sleepiness" (the likelihood of falling asleep), which is clinically distinct from "fatigue" or "tiredness." Patients with chronic fatigue syndrome may score low on the ESS despite feeling exhausted.
Clinical Pearls
A score > 10 is typically used as the primary cutoff for further investigation via polysomnography (PSG).
Patients with OSA often underestimate their sleepiness; collateral history from a partner ("Has he/she dozed off during a conversation?") is valuable.
Scores > 16 are frequently seen in untreated narcolepsy or severe sleep apnea.
Section 4
Next Steps
Next Steps
01
Score > 10: Complete a comprehensive sleep history. Check for snoring, observed apneas, and morning headaches.
02
Referral: Referral to a Sleep Specialist for PSG if OSA is suspected.
03
Safety Counseling: Counsel patients with high scores about the dangers of operating heavy machinery or long-distance driving.
Section 5
Evidence Appraisal
Primary Reference
A new method for measuring daytime sleepiness: the Epworth sleepiness scale
Johns MW. • Sleep. 1991;Vol 14, Issue 6. pp. 540-545. The foundational paper establishing the scale.
Section 6
Literature
Murray Johns
Developed by Dr. Murray Johns at the Epworth Hospital in Melbourne, Australia. It was created to provide a simple, self-administered alternative to the time-consuming Multiple Sleep Latency Test (MSLT).
