Narcolepsy tetrad

Four characteristic symptoms differentiate narcolepsy from other sleep disorders, and are known as the narcolepsy tetrad sleep attacks, cataplexy, hypnagogic hallucinations, and sleep paralysis. Individuals with narcolepsy complain of excessive daytime sleepiness, with sleep attacks that last up to 30 minutes. Individuals complain of hypersomnia, fatigue, impaired performance, and disturbed nighttime sleep. 

The sleep disorder narcolepsy, which affects around 1 in every 2000 people, is characterized by a tetrad of symptoms excessive daytime sleepiness, cataplexy (loss of muscle tone triggered by emotional arousal), hypnagogic hallucinations,... 

Narcolepsy (ICD G47.4) and other types of hypersomnia are severe disturbances of vigilance expressed as a sudden and irresistible requirement for sleep during the day, so-called sleep attacks (Aldrich. 1990). Apart from sleep attacks, the classical tetrad of narcolepsy includes cataplexy (sudden loss of muscular tone), sleep paralysis (waking from sleep with the feeling of not being able to move) and hypnagogic hallucinations (linages or sequences of... 

---