The symptoms of excessive daytime sleepiness (EDS) need to be assessed both clinically and with objective diagnostics. As with any other medical disorder, when patients present with excessive sleepiness, the first step is to determine the chief complaint. The spectrum of clinical presentations for EDS is wide, and patients may complain of fatigue, low energy, laziness, apathy, lethargy, poor memory, reduced concentration, reduced attention, irritability, poor performance in work/school, automatic behavior, frequent accidents, drowsiness, and/or sleep attacks. Oftentimes patients do not recognize their own excessive sleepiness and will not quantify the problem unless they are specifically asked if they are sleepy. Some of these patients only present because they have been referred by their employers due to their excessive sleepiness.
After the patient has noted his chief complaint, the clinician should assess the patient's score on the Epworth Sleeping Scale (ESS) on a quantifiable basis. The ESS is a self-administered questionnaire used to rate the severity of EDS. Respondents are asked to use a numeric scale from 0 to 3, corresponding to the likelihood (never, slight, moderate, and high) that they may fall asleep in eight given situations (Slide 1). An ESS score can range from 0 to 24. A score >9 indicates an abnormal level of sleepiness. A score >14 suggests marked sleepiness. Most patients with narcolepsy will score in this range. The normal range varies for different sleep disorders (Slide 2).