A REM Sleep Disorder - Narcolepsy

6 out of every 1000 people in the world are affected with Narcolepsy.

It has been estimated that about 250,000 people in United States have this type of sleep disorder.

Although there is a strong genetic factor linked to the disorder the exact cause of narcolepsy is not fully understood.

Relatives of narcolepsy sufferers are at a much greater risk for developing the disorder.

Narcolepsy is often viewed as a disorder of rapid eye movement (REM) sleep or as an imbalance between the physiologic mechanisms that control sleep and wake. Most of us go directly into non-rapid eye movement (NREM) sleep when we fall asleep at night.

We then enter REM sleep after approximately an hour and a half of NREM sleep. On the other hand, patients with narcolepsy often enter REM sleep as soon as they fall asleep, that is, they have sleep onset REM periods.

When patients with narcolepsy fall asleep unintentionally during the day, they also may enter REM sleep right away. This is why narcolepsy is considered a disorder of REM sleep.

However, patients with narcolepsy do not always enter REM sleep immediately. They may enter NREM sleep first, just as most of us do.

Symptoms of Narcolepsy

Narcolepsy commonly begins sometime between early teenage years and young adulthood. Irresistible daytime sleepiness is the first symptom to appear. Other symptoms may not appear until several years later.

Other symptoms such as cataplexy, sleep paralysis and hypnagogic hallucinations are the result of a partial activation of REM sleep while the person is still awake.

Cataplexy

Cataplexy is very much like the paralysis experienced during REM sleep. The difference is that this partial activation of REM sleep during cataplexy involuntarily intrudes on wakefulness. The brain waves during a cataplectic attack reveal a pattern suggesting wakefulness.

Sleep Paralysis

Sleep paralysis is like cataplexy, even though the narcolepsy patient is generally in bed. Hypnagogic hallucinations can be viewed as manifestations of REM sleep. It is as if while lying in bed, a dream improperly starts while the person is still conscious.

Narcolepsy patients tend to have “lighter” sleep at night and wake up more frequently than most individuals. They also tend to have excessive periodic limb movements during sleep.

However, the severe daytime sleepiness seen in narcolepsy is not explained by this phenomenon. Some patients with narcolepsy get plenty of good quality sleep at night and still they find themselves very sleepy during the day.