What is narcolepsy?
Narcolepsy is a disabling neurological disorder of sleep regulation that affects the control of sleep and wakefulness. Narcolepsy is a disorder that causes sudden episodes of deep sleep. These episodes can occur often and at inappropriate times, for example while a person is talking, eating or driving. Although sleep episodes can happen at any time, they may be more frequent during periods of inactivity or monotonous, repetitive activity. Narcolepsy is a rare disorder characterized by chronic, excessive attacks of drowsiness during the day, sudden extreme muscle weakness (cataplexy),
hallucinations, paralysis while sleeping, and disrupted sleep during the night. Attacks of drowsiness may persist only a few minutes or last for hours, and may vary in frequency from a few incidents to several during a single day. Although the exact cause of narcolepsy is not known, many researchers suspect that genetic factors play a role in the development of the disorder.
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. People with narcolepsy don't require extra hours of sleep, but they do need daytime naps because they have difficulty staying awake for long periods. During the night, healthy people normally progress through several stages of sleep before entering or leaving the state of sleep called rapid eye movement (REM). During REM sleep, your brain waves resemble those of an awake person, visual dreams occur, and muscle tone is slack. In narcolepsy, the brain-wave pattern can skip some or all of the other sleep stages, causing the person to move from the awake state immediately to REM sleep, or to awaken directly from the REM sleep stage.
In narcolepsy, the order and length of NREM and REM sleep periods are disturbed, with REM sleep occurring at sleep onset instead of after a period of NREM sleep. Thus, narcolepsy is a disorder in which REM sleep appears at an abnormal time. Also, some of the aspects of REM sleep that normally occur only during sleep--lack of muscle tone, sleep paralysis, and vivid dreams--occur at other times in people with narcolepsy. For example, the lack of muscle tone can occur during wakefulness in a cataplexy episode. Sleep paralysis and vivid dreams can occur while falling asleep or waking up.
Narcolepsy has its typical onset in adolescence and young adulthood. There is an average 15-year delay between onset and correct diagnosis, that may contribute substantially to the disabling features of the disorder. Cognitive, educational, occupational, and psychosocial problems associated with the excessive daytime sleepiness of narcolepsy have been documented. For these to occur in the crucial teen years when education, development of self-image, and development of occupational choice are taking place is especially damaging. While cognitive impairment does occur; it may only be a reflection of the excessive daytime somnolence.
Narcolepsy can occur in both men and women at any age, although its symptoms are usually first noticed in teenagers or young adults. There is strong evidence that narcolepsy may run in families; 8 to 12 percent of people with narcolepsy have a close relative with the disease. It is estimated that there are as many as 3 million people worldwide are affected by narcolepsy. In the United States it is estimated that narcolepsy afflicts as many as 200,000 Americans, but fewer than 50,000 are diagnosed. It is as widespread as Parkinson's disease or multiple sclerosis and more prevalent than cystic fibrosis, but it is less well known. Narcolepsy is often mistaken for depression, epilepsy, or the side effects of medications.