Narcolepsy is a chronic neurological disorder caused by the brain's inability to regulate sleep-wake cycles normally. At various times throughout the day, people with narcolepsy experience irresistible bouts of sleep. If the urge becomes overwhelming, individuals will fall asleep for periods lasting from a few seconds to several minutes. In rare cases, some people may remain asleep for an hour or longer.
Narcolepsy is not definitively diagnosed in most patients until 10 to 15 years after the first symptoms appear. The cause of narcolepsy remains unknown. It is likely that narcolepsy involves multiple factors interacting to cause neurological dysfunction and sleep disturbances.
Who Gets Narcolepsy?
Narcolepsy affects both males and female equally and appears throughout the world. It most often starts in childhood or adolescence. Narcolepsy is not rare, but it is an under-recognized and under-diagnosed condition. More than 200,000 Americans and 3 million people worldwide are living with narcolepsy.
What are the symptoms?
Narcolepsy is a lifelong problem, but it does not usually worsen as the person ages. Symptoms can partially improve over time, but they will never disappear completely. The most typical symptoms are excessive daytime sleepiness, cataplexy, sleep paralysis, and hallucinations. Though all have excessive daytime sleepiness, only 10 to 25 percent of affected individuals will experience all of the other symptoms during the course of their illness.
Excessive daytime sleepiness (EDS). All individuals with narcolepsy have EDS, and it is often the most obvious symptom. EDS is characterized by persistent sleepiness, regardless of how much sleep an individual gets at night. However, sleepiness in narcolepsy is more like a “sleep attack”, where an overwhelming sense of sleepiness comes on quickly. In between sleep attacks, individuals have normal levels of alertness, particularly if doing activities that keep their attention.
• Cataplexy. This sudden loss of muscle tone while a person is awake leads to weakness and a loss of voluntary muscle control. It is often triggered by sudden, strong emotions such as laughter, fear, anger, stress, or excitement. The symptoms of cataplexy may appear weeks or even years after the onset of EDS. Some people may only have one or two attacks in a lifetime, while others may experience many attacks a day. In about 10 percent of cases of narcolepsy, cataplexy is the first symptom to appear and can be misdiagnosed as a seizure disorder. Attacks may be mild and involve only a momentary sense of minor weakness in a limited number of muscles, such as a slight drooping of the eyelids. The most severe attacks result in a total body collapse during which individuals are unable to move, speak, or keep their eyes open. But even during the most severe episodes, people remain fully conscious, a characteristic that distinguishes cataplexy from fainting or seizure disorders. The loss of muscle tone during cataplexy resembles paralysis of muscle activity that naturally occurs during REM sleep. Episodes last a few minutes at most and resolve almost instantly on their own. While scary, the episodes are not dangerous as long as the individual finds a safe place in which to collapse.
Sleep paralysis. The temporary inability to move or speak while falling asleep or waking up usually lasts only a few seconds or minutes and is similar to REM-induced inhibitions of voluntary muscle activity. Sleep paralysis resembles cataplexy except it occurs at the edges of sleep. As with cataplexy, people remain fully conscious. Even when severe, cataplexy and sleep paralysis do not result in permanent dysfunction—after episodes end, people rapidly recover their full capacity to move and speak.
Hallucinations. Very vivid and sometimes frightening images can accompany sleep paralysis and usually occur when people are falling asleep or waking up. Most often the content is primarily visual, but any of the other senses can be involved.
Additional symptoms of narcolepsy include:
Fragmented sleep and insomnia. While individuals with narcolepsy are very sleepy during the day, they usually also experience difficulties staying asleep at night. Sleep may be disrupted by insomnia, vivid dreaming, sleep apnea, acting out while dreaming, and periodic leg movements.
Automatic behaviors. Individuals with narcolepsy may experience temporary sleep episodes that can be very brief, lasting no more than seconds at a time. A person falls asleep during an activity (e.g., eating, talking) and automatically continues the activity for a few seconds or minutes without conscious awareness of what they are doing. This happens most often while people are engaged in habitual activities such as typing or driving. They cannot recall their actions, and their performance is almost always impaired. Their handwriting may, for example, degenerate into an illegible scrawl, or they may store items in bizarre locations and then forget where they placed them. If an episode occurs while driving, individuals may get lost or have an accident. People tend to awaken from these episodes feeling refreshed, finding that their drowsiness and fatigue has temporarily subsided.
There are two major types of narcolepsy:
Type 1 narcolepsy (previously termed narcolepsy with cataplexy). This diagnosis is based on the individual either having low levels of a brain hormone (hypocretin) or reporting cataplexy and having excessive daytime sleepiness on a special nap test.
Type 2 narcolepsy (previously termed narcolepsy without cataplexy). People with this condition experience excessive daytime sleepiness but usually do not have muscle weakness triggered by emotions. They usually also have less severe symptoms and have normal levels of the brain hormone hypocretin.
A condition known as secondary narcolepsy can result from an injury to the hypothalamus, a region deep in the brain that helps regulate sleep. In addition to experiencing the typical symptoms of narcolepsy, individuals may also have severe neurological problems and sleep for long periods (more than 10 hours) each night.
What treatments are available?
Although there is no cure for narcolepsy, some of the symptoms can be treated with medicines and lifestyle changes. When cataplexy is present, the loss of hypocretin is believed to be irreversible and lifelong. Excessive daytime sleepiness and cataplexy can be controlled in most individuals with medications.
Narcolepsy can be difficult to diagnose because some of its symptoms, such as fatigue, are common to many conditions. The average time between the onset of symptoms and diagnosis is seven years.
Narcolepsy is diagnosed through a sleep study, a set of medical tests requiring an overnight stay in a sleep lab.
To schedule an appointment call (910) 295-6868 or to learn more visit: http://narcolepsynetwork.org/about-narcolepsy/faq/