This neurological disorder causes excessive daytime sleepiness and frequent, often daily, bouts of an irrepressible need to sleep, or lapses into sleep. People awaken feeling refreshed, but later experience additional bouts of sleepiness.
While narcolepsy is rare, affecting only about one in 2,000 people, it poses a danger to people with safety-critical jobs. Railroaders and other working in such jobs likely have been asked about possible narcolepsy symptoms in their pre-employment health screening and periodic health exams. Narcolepsy usually emerges between ages 10 and 25 years. When mild, narcolepsy may not be diagnosed until later in life. Symptoms include:
- Sleep attacks: People with narcolepsy may fall asleep suddenly in the midst of ordinary activities such as eating, talking, walking, or driving. Despite having sleep episodes in waking hours, they often have trouble sustaining sleep when they attempt to rest.
- Cataplexy: People with narcolepsy occasionally experience sudden muscle weakness in the legs, arms, or face. These episodes usually are triggered by strong emotions, such as laughter or surprise. In extreme instances, people may fall down, appear to be asleep, and not be able to move for a few seconds to a minute or more. They remain conscious, and even though they can’t open their eyes, they can recount later what went on around them.
- Hypnagogic hallucinations: People with narcolepsy may experience intense dream-like imagery and sensations when they drift off to sleep. That experience can be alarming when it occurs in normal waking hours, and dangerous if occurs in situations such as driving. Even healthy individuals sometimes have a similar dream-like experience, typically just as they are falling asleep or waking up. The hallucinations represent the intrusion of dreaming sleep into wakefulness. When these hallucinations occur, a person is in essence both awake and asleep at the same time.
- Sleep paralysis: People with narcolepsy sometimes find they cannot talk or move for a few seconds or even a few minutes as they wake up or fall asleep. Since they want to act, but somehow are prevented from doing so, the experience often is frightening. Sleep paralysis is another example of being partly asleep and partly awake at the same time. It sometimes occurs even in healthy people, particularly if they are overtired.
Treatment for narcolepsy
The diagnosis of narcolepsy usually requires observation of both sleep and waking behavior in the sleep laboratory. While no cure exists for narcolepsy today, stimulants and other wake-promoting medications can reduce daytime sleepiness. Antidepressants and other medications can help prevent cataplexy, sleep paralysis, and hypnagogic hallucinations. Frequent, regular daytime naps often help reduce sleep attacks.