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Narcolepsy is a neurological condition characterized by severe fatigue, irresistible episodes of sleep and general sleep disorder. It is a kind of dyssomnia. more...
Neurofibromatosis type 2
Nijmegen Breakage Syndrome
Symptoms of narcolepsy
The main characteristic of narcolepsy is overwhelming excessive daytime sleepiness (EDS), even after adequate nighttime sleep. A person with narcolepsy is likely to become drowsy or to fall asleep, often at inappropriate times and places. Daytime naps may occur with or without warning and may be irresistible. These naps can occur several times a day. Drowsiness may persist for prolonged periods of time. In addition, night-time sleep may be fragmented with frequent wakenings.
Three other classic symptoms of narcolepsy, which may not occur in all patients, are:
- Cataplexy: sudden episodes of loss of muscle function, ranging from slight weakness (such as limpness at the neck or knees, sagging facial muscles, or inability to speak clearly) to complete body collapse. Episodes may be triggered by sudden emotional reactions such as laughter, anger, surprise, or fear, and may last from a few seconds to several minutes. The person remains conscious throughout the episode.
- Sleep paralysis: temporary inability to talk or move when falling asleep or waking up. It may last a few seconds to minutes.
- Hypnagogic hallucinations: vivid, often frightening, dream-like experiences that occur while dozing, falling asleep and/or while awakening.
Daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic hallucinations also occur in people who do not have narcolepsy, more frequently in people who are suffering from extreme lack of sleep.
In most cases, the first symptom of narcolepsy to appear is excessive and overwhelming daytime sleepiness. The other symptoms may begin alone or in combination months or years after the onset of the daytime naps. There are wide variations in the development, severity, and order of appearance of cataplexy, sleep paralysis, and hypnagogic hallucinations in individuals. Only about 20 to 25 percent of people with narcolepsy experience all four symptoms. The excessive daytime sleepiness generally persists throughout life, but sleep paralysis and hypnagogic hallucinations may not.
The symptoms of narcolepsy, especially the excessive daytime sleepiness and cataplexy, often become severe enough to cause serious disruptions in a person's social, personal, and professional lives and severely limit activities.
What happens in narcolepsy
Normally, when an individual is awake, brain waves show a regular rhythm. When a person first falls asleep, the brain waves become slower and less regular. This sleep state is called non-rapid eye movement (NREM) sleep. After about an hour and a half of NREM sleep, the brain waves begin to show a more active pattern again, even though the person is in deep sleep. This sleep state, called rapid eye movement (REM) sleep, is when dreaming occurs.
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From Gale Encyclopedia of Childhood and Adolescence,
Narcolepsy, which usually begins in adolescence or early adulthood, affects about one in every 1,000 persons and is equally common in males and females. The sleep attacks, which can occur anywhere from six to 20 times a day, usually last about 10 to 20 minutes but can persist for as long as two to three hours. Narcolepsy is diagnosed if sleep attacks occur every day for at least three months (although most people treated for the disorder suffer from it for a much longer period of time--often years--before seeking help). In addition to the sleep attacks, persons suffering from narcolepsy often display several other characteristic symptoms. The most debilitating of these is cataplexy, a sudden loss of muscle tone that can affect a part or all of the body. Cataplectic attacks range from a sagging jaw or drooping head to a total collapse that causes the person to fall to the ground. Affecting about 70% of narcoleptics, they are usually triggered by strong emotions, ranging from fear and anger to excitement and amusement (laughter often provokes cataplectic attacks). Respiration is not affected, and full consciousness is maintained throughout the episode. Usually the attacks only last a few seconds, after which normal muscle strength returns. Other symptoms of narcolepsy include vivid dreamlike imagery while waking or falling asleep, episodes of sleep paralysis (in which the person wakes but is temporarily unable to move), and automatic behavior (sleepwalking-type actions which are performed without the person's conscious knowledge).
The cause of narcolepsy is not known, but sleep researchers believe it comes from a malfunction of the mechanism in the brain that regulates sleeping and waking, especially the regulation of REM (rapid eye movement) sleep, the part of the sleep cycle associated with dreaming. It is also known that there is a hereditary component to narcolepsy: having a narcoleptic parent dramatically increases one's chances of developing the disorder, from the normal 1 in 1,000 to 1 in 20. In recent research, a genetic marker has been found in the blood of over 95% of narcolepsy sufferers who were tested for it. Narcolepsy may also develop as a consequence of brain damage caused by injury or disease.
Narcolepsy is a chronic illness that lasts throughout a person's lifetime and has no known cure. Napping during the daytime can reduce the number of sleep attacks by lessening sleepiness. For those severely affected by the disorder, stimulants such as methylphenidate (Ritalin) and Dexedrine have been prescribed to ward off sleep attacks. Cataplexy--thought to be a partial intrusion of REM sleep into the waking state--has been treated with medications known to suppress REM sleep, such as tricyclic antidepressants . Doctors have had good results with another medication, the experimental drug gamma-hydroxybutyrate, prescribed for narcoleptics to improve the quality of their nighttime sleep, which is usually fitful and fragmented. The resulting improvement of nighttime sleep has had marked success in the reduction (and in some cases complete remission) of symptoms, including both daytime sleep attacks and cataplexy. To avoid the potential danger and embarrassment of cataleptic episodes, some persons with narcolepsy try to control the emotions that trigger them, even avoiding situations that are likely to bring on these emotions.
Narcolepsy has a crippling effect on the lives of those afflicted with it, causing disruption, embarrassment, and, potentially, danger in their everyday lives and interfering with both work and family life. Self-help groups sponsored by the American Narcolepsy Association (and a similar group in Canada) offer support to narcoleptics and their families. These organizations also work to help raise public awareness about the disorder.
For Your Information
- Dement, William C. The Sleepwatchers. Stanford: Stanford Alumni Association, 1992.
- Dotto, Lydia. Losing Sleep: How Your Sleeping Habits Affect Your Life. New York: William Morrow, 1990.
- Ince, Susan. Sleep Disturbances. Boston: Harvard Medical School, Health Publications Groups, 1995.
Gale Encyclopedia of Childhood & Adolescence. Gale Research, 1998.
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