NARCOLEPSY

Narcolepsy

Narcolepsy is a sleep disorder that occurs when the brain fails to regulate sleep-wake cycles. This can result in people falling asleep at inappropriate times, such as while working, having a conversation, and, most dangerously, while driving a car. Other characteristic symptoms include cataplexy (a sudden loss of voluntary muscle tone) and brief episodes of total paralysis at the beginning or end of sleep.

What Is Narcolepsy?

Narcolepsy is a chronic sleep disorder resulting from the brain's inability to regulate sleep-wake cycles. At various times throughout the day, people with narcolepsy experience the fleeting urge to sleep. If the urge becomes overwhelming, patients 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. There is no known cure for narcolepsy.

Although it is estimated that this condition afflicts as many as 200,000 Americans, fewer than 50,000 are diagnosed. It is as widespread as Parkinson's disease or multiple sclerosis (MS) and more prevalent than cystic fibrosis, but it is not as well known. Narcolepsy is often mistaken for depression, epilepsy, or the side effects of medications.

  

Understanding Sleep States

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.

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 Symptoms

In severe cases, narcolepsy symptoms can cause serious disruptions in a person's social, personal, and professional life. The classic symptom is excessive and overwhelming daytime sleepiness. Other symptoms of narcolepsy include cataplexy, sleep paralysis, and hypnagogic hallucinations. In most cases, the first symptom to appear is excessive and overwhelming daytime sleepiness.

An Introduction to Narcolepsy Symptoms and Signs 

Narcolepsy is a chronic condition caused by the brain's inability to regulate sleep-wake cycles normally. At various times throughout the day, people with narcolepsy experience the fleeting urge to sleep. If the urge becomes overwhelming, people 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.

The classic narcolepsy symptom is excessive and overwhelming daytime sleepiness. Three other classic symptoms, which may not occur in all people, are:

• Cataplexy
• Sleep paralysis
• Hypnagogic hallucinations.

Excessive Daytime Sleepiness

The characteristic symptom of narcolepsy is excessive and overwhelming daytime sleepiness, 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 sleep attacks may occur with or without warning and may be irresistible. These attacks can occur repeatedly in a single day. Drowsiness may persist for prolonged periods of time. In addition, nighttime sleep may be fragmented, with frequent interruptions.

Cataplexy

Cataplexy is another symptom of narcolepsy. This is a sudden episode 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. Attacks may be triggered by sudden emotional reactions, such as laughter, anger, or fear, and may last from a few seconds to several minutes. The person remains conscious throughout the episode

Cause of Narcolepsy

It is not known exactly why narcolepsy occurs. However, researchers currently believe that multiple factors interact to cause the disorder. Some researchers believe that narcolepsy is caused by a variation of certain genes located on chromosome 6. Other possible causes include tumor growth and traumatic injuries to certain parts of the brain involved in rapid eye movement (REM) sleep.

  

An Introduction to the Cause of Narcolepsy

No one knows the exact cause or causes of narcolepsy (a condition characterized by brief attacks of deep sleep). Doctors can seldom explain why one person gets narcolepsy and another does not. Research scientists currently believe that narcolepsy may be caused by multiple factors interacting to cause neurological dysfunction and sleep disturbances.

Genetic Influence

One possible cause of narcolepsy is a variation of certain genes located on chromosome 6. This gene portion, known as HLA complex, has been shown to be associated with narcolepsy. The majority of people diagnosed with narcolepsy have specific variations in these HLA genes. However, many people in the general population without narcolepsy also have these variations. Therefore, scientists believe the altered HLA gene increases an individual's chance of developing narcolepsy, but it is not the only reason a person develops narcolepsy.

Many other genes besides the HLA complex may contribute to the development of narcolepsy.

Other Possible Narcolepsy Causes

Other factors appear to play important roles in the development of narcolepsy. Some rare cases of narcolepsy are known to result from traumatic injuries to parts of the brain involved in REM sleep or from tumor growth and other disease processes in the same regions.

Some other factors that could have an effect on the development of narcolepsy include:

• Infections
• Exposure to toxins
• Dietary factors
• Stress
• Hormonal changes (such as those occurring during puberty or menopause).