Sleepiness in Narcolepsy.

Narcolepsy represents the best understood disorder of excessive daytime sleepiness (EDS). EDS presents in 100% of patients with narcolepsy; it is usually the first and the most disabling symptom, which varies in aspects, such as onset age, severity, and clinical characteristics. Early recognition of this symptom leads to early diagnosis and intervention. A diagnosis of narcolepsy is based on clarifying EDS through history, subjective evaluation using questionnaires, and objective measurement, including nocturnal polysomnography followed by a daytime multiple sleep latency test. The therapeutic goal is to optimize control of EDS through wake-promoting medications and nonpharmacologic treatments.