While most cases of narcolepsy are sporadic, about 10% of individuals report having a close relative with similar symptoms. However, the precise cause of hypocretin cell loss is unknown. Researchers believe that people with narcolepsy have an overly reactive immune system that attacks the hypocretin-containing brain cells. Other genes known as the human leukocyte antigen (HLA) may also play a role in the onset of type 1 narcolepsy.Īlthough the cause of narcolepsy is not entirely understood, some related factors include: This variant gene gives people a genetic predisposition to developing narcolepsy. T-cells are specialized immune cells that play a role in all immune system responses. Researchers note that the number of neurons that produce hypocretin is significantly lower in individuals with narcolepsy.Ī study from 2009 discovered that people with narcolepsy tend to have abnormal T-cell receptor genes. This brain chemical plays a critical role in regulating sleep and other brain functions.

There’s a link between low levels of hypocretin and people with type 1 narcolepsy. The precise cause of narcolepsy remains unknown. This happens when you’re actively engaged in an activity, like typing or driving. You may fall asleep and automatically continue the activity for a few seconds or minutes without realizing you’re doing it. Automatic behaviorsīecause people with narcolepsy can fall asleep for a few seconds during certain activities, it’s common for them to adapt automatic behaviors. This is why narcolepsy can be misdiagnosed with other sleep conditions, such as obstructive sleep apnea, insomnia, and restless leg syndrome. Narcolepsy can also disrupt sleep with vivid dreaming, insomnia, and periodic leg movements. In most cases, hallucinations occur in conjunction with sleep paralysis and tend to be visual, but other senses can be involved too. Some people also experience hallucinations that occur at the beginning or end of a sleep period. Once the paralysis episodes end, people recover their total capacity to move and speak. Sleep paralysis often occurs in moments when people are conscious and somewhat awake. Symptoms of sleep paralysis usually don’t last for more than a few minutes. Sleep paralysis is a temporary inability to speak or move while falling asleep or waking up. In some cases, you may experience a complete loss of muscle control or paralysis for a few minutes.ĭuring a severe cataplexy attack, speech and movement may become almost impossible, although there is no loss of consciousness. You may experience attacks that cause your knees to buckle, jaw to sag, eyelids to drop, or head to fall. Episodes can last a few seconds or extend to a few minutes. It often happens during times of intense emotions, such as laughter, anger, or surprise. CataplexyĬataplexy is a sudden, temporary loss of muscle control. These episodes of excessive daytime sleepiness can occur at any time, during any activity. In between “sleep attacks,” people have normal levels of alertness.

This is a sudden overwhelming urge to sleep, despite feeling rested. The following sections look at these symptoms in more detail: Excessive daytime sleepiness While excessive daytime drowsiness affects everyone with narcolepsy, only 10% to 25% of people will experience all of the other symptoms, too. The most common symptoms of narcolepsy are: In most cases, it’s a lifelong condition. While the severity of the symptoms may vary over time, the disorder itself is not progressive, meaning it doesn’t get worse over time. Other names for narcolepsy, though not commonly used, include: This explains the loss of muscle tone and the vivid visual hallucinations patients with narcolepsy may experience during the sleep attacks They can also enter this sleep stage during periods of wakefulness. Someone with narcolepsy may enter REM sleep immediately. To prevent us from acting out on our dreams, our brain sends signals to our muscles and limbs to become paralyzed. It takes an average adult about 90 minutes to enter rapid eye movement (REM) sleep. To better understand the symptoms of narcolepsy, we need to learn more about how a regular sleep cycle works: These episodes vary in frequency and can occur multiple times during a single day. Attacks of sleepiness can last a few seconds or several minutes. This is called daytime sleepiness, sometimes called EDS. Narcolepsy, a neurological sleep-wake disorder, causes chronic attacks of sleepiness during the day and poor sleep at night.

Narcolepsy and cataplexy brain