Nancy was sleeping again. Her husband and children were ready to go out but she was not. This has been the story of her life. In school she was always falling asleep. Then at night, she had trouble staying asleep. She would sometimes awaken unable to move. That was scary enough, but at times these episodes were even more frightening as she was aware of an apparent presence in her room and sometimes even saw people when nobody was there. They were always just part of a dream. Most upsetting were the times she would get startled, or was laughing at a very funny joke or got very angry — and she would just fall to the ground — unable to move for several minutes. This had gone on for most of her life and had caused great difficulty with teachers, friends and family who couldn't understand why she was like this. In fact, it was only a few years ago that she finally got a diagnosis that explained her problem. Nancy has been suffering her entire life with the sleep disorder known as narcolepsy.

Narcolepsy is a neurological disorder that was first identified by Jean Baptiste Edouard Gelineau in 1880. He coined the term narcolepsy from the Greek terms narkosis ("a benumbing") and lepsis ("to overtake"). It is characterized by excessive daytime sleepiness, cataplexy, hypnagogic hallucinations and sleep paralysis. Narcolepsy is associated with the loss of hypothalamic neurons that contain the neuropeptide hypocretin. Narcolepsy is one of a group of sleep disorders known as hypersomnias. These disorders are characterized by excessive daytime sleepiness that does not occur because of sleep deprivation, other sleep disorders (such as sleep apnea or insomnia) or because the person's 24 hour day/night rhythm is disturbed. Narcolepsy may also occur secondary to other medical conditions such as head trauma, stroke, Multiple Sclerosis, brain tumors, neurodegenerative disorders and central nervous system infections.

Narcolepsy is relatively rare with a prevalence of 0.02% to 0.18% in the general population. It usually starts in adolescence but can have a first onset after 40 years of age. It is also seen in children. About 10% of cases start before age 10 and 5% after age 50. The earliest symptom to manifest itself is excessive daytime sleepiness with other symptoms developing later. About 70% of narcoleptics have episodes of cataplexy. Sleep paralysis occurs in 40% to 80% of people with narcolepsy. Around 50% of those with narcolepsy have disrupted nocturnal sleep with the most common problem being sleep maintenance insomnia.

Many symptoms of narcolepsy are related to the abnormal regulation of REM sleep with the inappropriate intrusion of REM sleep physiology (for example, muscle paralysis) into daytime wakefulness. Cataplexy is the sudden muscle weakness that is induced by strong emotional states such as laughter or anger. It can vary in intensity and range from mild (with the head dropping or the knees buckling) to severe (with the person falling to the ground unable to move). Hypnagogic hallucinations result from REM sleep occurring abnormally early in the sleep cycle (short REM latency) with dreaming at sleep onset. These hallucinations are often vivid and may involve experiences such as being in a fire or flying, and often have strong feelings of fear associated with them. Sleep paralysis is the loss of muscle tone when waking up or falling asleep and can be a fearful experience. At times patients with narcolepsy may have automatic behaviors. These occur when the person continues engaging in whatever behavior he or she was doing, but in a semiautomatic way without conscious awareness. The person may find, for example, that she is suddenly in another room holding a mug of coffee with no memory of getting the coffee or walking to the new location. Automatic behavior episodes during periods of reduced arousal can last as long as 30 minutes with semi-purposeful behavior and amnesia for the interval. This is sometimes described as a "blackout" and can even appear like a seizure.

The daytime sleepiness seen in narcolepsy is different from mere fatigue and involves frequently falling asleep during the day. With normal fatigue, rest may be helpful, but for a person suffering from narcolepsy rest is not enough and there is a strong need for sleep in the form of naps which may be brief or lengthy. The degree of sleepiness can vary greatly in severity. Excessive daytime sleepiness is frequently very disruptive to the person's life as it interferes with the ability to function during the day and to hold down a job, go to school, or take care of children. The person has repeated episodes of falling asleep or taking naps. After a brief nap or sleep attack the person will often feel refreshed but after a short time will begin to experience sleepiness again. Sleepiness is most likely to occur during boring tasks or when sedentary such as watching TV. These symptoms are chronic and last for years. In the modern world this is an extremely difficult problem as our fast-paced, demanding, society generally requires a high degree of alertness during the day.

What can you do if you have or a loved one has symptoms that may be suggestive of this disorder? First, a consultation with your primary care physician is in order. Based on the initial evaluation a particular treatment to address daytime sleepiness or disrupted sleep may be suggested. A diagnosis of narcolepsy involves a careful review of the symptom history as well as an over-night sleep study followed by a daytime nap study. Treatment may involve both medication management and behavioral interventions. Behavioral techniques such as taking planned naps can be beneficial in managing daytime sleepiness. Medications may be used to target the daytime sleepiness with alerting agents, the abnormal REM physiology with antidepressants to suppress REM sleep, or the disturbed nocturnal sleep with medications to increase sleep consolidation.

While narcolepsy is an unwelcome intrusion into our busy, twenty-first century lives, all is not lost. Narcolepsy can indeed be managed with medications and behavioral techniques, and life, albeit, somewhat drowsily, does go on.

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