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excessive daytime

What is EDS?

Excessive daytime sleepiness (EDS) is defined as the inability to maintain wakefulness and alertness during the major waking episodes of the day, resulting in periods of irrepressible need for sleep or unintended lapses into drowsiness or sleep.*

EDS is present in all patients with narcolepsy and is one of the most common symptoms of obstructive sleep apnea (OSA). Common signs and symptoms of EDS include frequent tiredness, unrefreshing sleep, and brain fog. Patients may experience impaired attention, memory, and executive functioning skills. EDS may negatively impact relationships, job performance, and daily activities.

EDS in narcolepsy

  • Narcolepsy affects an estimated 185,000 people in the U.S and all people with narcolepsy experience EDS
  • EDS is often one of the first and most disabling symptoms to develop in people with narcolepsy


  • Approximately 22 million Americans or 10% of U.S. adults have moderate to severe sleep apnea
  • Continuous positive airway pressure therapy (CPAP) is the most common and an essential part of treatment for sleep apnea, but it may not completely relieve symptoms of EDS, with ~12-65% of patients having lasting EDS despite optimal CPAP use
  • In a study of patients with OSA
    • 52% reported feeling sleepy during the day despite any amount of CPAP use†‡
    • 1 in 3 who used their CPAP for 5 or more hours a night, still reported feeling sleepy during the day†

key facts

in a clinical research study with 822 patients newly diagnosed with moderate-to-severe OSA referred for positive airway pressure (PAP) treatment§


reported involuntary sleep episodes while driving


reported falling asleep while relaxing


reported involuntary sleep episodes during the day

*As defined by the American Academy of Sleep Medicine (AASM).
A study of 174 patients with moderate-to-severe OSA using CPAP. Daytime sleepiness was assessed before and after 3 months of CPAP therapy using the Epworth Sleepiness Scale.
Includes average CPAP use of 2 or fewer hours per night, up to 7 or more hours per night.
§A study of newly diagnosed patients from the Icelandic Sleep Apnea Cohort identified subtypes of patients with OSA who experienced distinct combinations of symptoms and comorbidities. The percentages shown are for patients from the EDS subgroup (N=350).