Narcolepsy and its symptoms

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Narcolepsy is also characterised by interrupted night sleep or sleeping after meals.

Narcolepsy is a neurological disease that lasts the entire life. It is a sleep disorder which is most evident as excessive and uncontrollable daily sleepiness. For the establishment of a diagnosis of narcolepsy, at least two major symptoms of narcolepsy must be confirmed in the person: daily excessive daytime sleepiness, which occurs for at least three months and the presence of cataplexy.

What are the main symptoms of narcolepsy?

Excessive daytime sleepiness

It is a sign for a situation in which a person feels an unbearable need for sleep, although at night he/she slept long enough. Severe fatigue during the day occurs in every person with narcolepsy. Excessive daily sleepiness is experienced by patients at a time when they are not allowed to sleep or do not want to – for example, in the middle of a conversation, when driving a car, during work or while eating. The patient is not able to stay awake in circumstances requiring absolute alertness and concentration. Daily sleep attacks can occur without prior warning, even several times a day. Excessive daily sleepiness and unpredictable short naps during the day may result in accidents at work and in traffic. A patient who is sleepy all the time feels a bit better after a short nap.

Cataplexy

It is the second most common symptom of narcolepsy. It occurs in 60% to 90% of patients with narcolepsy. Patients describe cataplexy as a sudden, short-term loss of muscle strength, which always occurs at a sudden emotional event (laughter, anger, surprise, mourning, disappointment, embarrassment, enthusiasm, or sexual arousal).

The forms of cataplexy differ in degree of severity: partial (buckling of knees, hand weakness, facial muscles become loose, the head falls back, speech becomes unclear and incoherent) or complete (it can weaken the entire body so that the person suddenly collapses as a sack). A cataplexy attack usually lasts a few seconds to a few minutes. The affected person is aware of the events (is constantly conscious) but is not able to speak or react.

Cataplexy symptoms are seen in people aged 15 to 30 years, usually after the symptoms of excessive daytime sleepiness occur. Frequency of attacks is different: from several attacks a day to a few attacks per year. 75% of all individuals with cataplexy report at least one cataplexy attack per day.

Interrupted night sleep or sleeping after meals

Narcolepsy is also characterised by interrupted night sleep or sleeping after meals. Interrupted sleep and frequent awakening is typical for 60% to 80% of people with narcolepsy. Patients with narcolepsy do not sleep more than healthy people in the 24-hour period; the interrupted night-time sleep deficiency is reflected as a severe excessive daytime sleepiness and sleep-attacks over the day. "Sleep after meals" is not only a symptom of insomnia, but also narcolepsy.

Hypnagogic and hypnopompic hallucinations

Hallucinations are alive, unpleasant dreams similar to those experienced in 80% of people with narcolepsy, during the person's onset of sleep (hypnagogic hallucinations) and during waking-up (hypnopopulated hallucination). The images look very real and can cause horror. They are caused by the collapsed sleep architecture in narcolepsy and instantaneous sleeping into the REM (rapid eye movement) phase.

Paralyses when sleeping and awakening

Paralysis is a short-term incapability of speaking or moving at the moment when the person falls asleep or awakes. 80% of people with narcolepsy report this disorder. Morning or evening paralysis can last from a few seconds to a few minutes. Although the condition is not dangerous, those who do not realise that they have a sleep disorder, are frightened by it, especially if accompanied by hypnagogic hallucinations. Paralysis also occurs as a result of disturbed REM sleep (see description below).