What is interrupted sleep

Interrupted sleep also known as narcolepsy, is a chronic sleep disorder that causes periods of extreme daytime sleepiness, drowsiness and sudden attacks of sleep. The disorder also may cause muscle weakness ¹. People with narcolepsy usually feel rested after waking, but then feel very sleepy throughout much of the day. People with interrupted sleep disorder often find it difficult to stay awake for long periods of time, regardless of the circumstances. Narcolepsy can cause serious disruptions in your daily routine. Some people who have the interrupted sleep disorder fall asleep suddenly, even if they’re in the middle of driving, talking, eating, or another activity.

Sometimes, interrupted sleep or narcolepsy can be accompanied by a sudden loss of muscle tone (cataplexy) that leads to weakness and loss of muscle control. Cataplexy is often triggered by a strong emotion, most commonly laughter.

Narcolepsy also can cause:

• Cataplexy. This condition causes a sudden loss of muscle tone while you’re awake. Muscle weakness can affect certain parts of your body or your whole body. For example, if cataplexy affects your hand, you may drop what you’re holding. Strong emotions often trigger this weakness. It may last seconds or minutes.

• Hallucinations. These vivid dreams occur while falling asleep or waking up.

• Sleep paralysis. This condition prevents you from moving or speaking while waking up and sometimes while falling asleep. Sleep paralysis usually goes away within a few minutes.

Most people who have narcolepsy have trouble sleeping at night. Many individuals with narcolepsy also experience uneven and interrupted sleep that can involve waking up frequently during the night.

Narcolepsy is a chronic condition for which there’s no cure. However, medications and lifestyle changes can help you manage the symptoms. Support from others — family, friends, employer, teachers — can help you cope with narcolepsy.

How common is interrupted sleep disorder ?

Narcolepsy affects both males and females equally. Symptoms often start in childhood, adolescence, or young adulthood (ages 7 to 25), but can occur at any time in life. It is estimated that anywhere from 135,000 to 200,000 people in the United States have narcolepsy. However, since this condition often goes undiagnosed, the number may be higher. Since people with narcolepsy are often misdiagnosed with other conditions, such as psychiatric disorders or emotional problems, it can take years for someone to get the proper diagnosis.

Overview of Sleep

The two main phases of sleep are nonrapid eye movement (NREM) and rapid eye movement (REM). Most people are in the nonrapid eye movement (NREM) phase when they first fall asleep. After about 90 minutes of sleep, most people go from NREM to rapid eye movement (REM) sleep.

Dreaming occurs during the rapid eye movement (REM) phase of sleep. During REM, your muscles normally become limp. This prevents you from acting out your dreams.

People who have interrupted sleep disorder (narcolepsy) often fall into REM sleep quickly and wake up directly from it. As a result, they may have vivid dreams while falling asleep and waking up.

Hypocretin, a chemical in the brain, helps promote wakefulness. Most people who have interrupted sleep disorder (narcolepsy) have low levels of this chemical.

What causes these low levels isn’t well understood. Researchers think that certain factors may work together to cause a lack of hypocretin. These factors may include heredity, infections, brain injuries, and autoimmune disorders. (Autoimmune disorders occur if the body’s immune system mistakenly attacks the body’s cells and tissues.)

What are the types of interrupted sleep disorder ?

There are two major types of interrupted sleep disorder (narcolepsy) ²:

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.

Effects of interrupted sleep disorder

Interrupted sleep disorder (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

All individuals with narcolepsy have excessive daytime sleepiness and it is often the most obvious symptom. Excessive daytime sleepiness 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. People with narcolepsy fall asleep without warning, anywhere, anytime. For example, you may suddenly nod off while working or talking with friends. You may sleep for a few minutes or up to a half-hour before awakening and feeling refreshed, but eventually you fall asleep again.

You also may experience decreased alertness throughout the day. Excessive daytime sleepiness usually is the first symptom to appear and is often the most troublesome, making it difficult for you to concentrate and fully function.

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 – can cause a number of physical changes, from slurred speech to complete weakness of most muscles, and may last for a few seconds to a few minutes. 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 excessive daytime sleepiness. Some people may only have one or two attacks in a lifetime or in a year, 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 or your head may droop uncontrollably or your knees may suddenly buckle when you laugh. 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.

Not everyone with narcolepsy experiences cataplexy.

Sleep paralysis

The temporary inability to move or speak while falling asleep or waking up usually lasts only a few seconds or minutes — but can be frightening 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.

Not everyone with sleep paralysis has narcolepsy, however. Many people without narcolepsy experience some episodes of sleep paralysis, especially in young adulthood.

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 (restless legs syndrome).

• 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.

• Obstructive sleep apnea. Obstructive sleep apnea, a condition in which breathing starts and stops throughout the night.
• People with narcolepsy may also act out their dreams at night by flailing their arms or kicking and screaming.

Interrupted sleep causes

Narcolepsy may have several causes. Nearly all people with narcolepsy who have cataplexy have extremely low levels of the naturally occurring chemical hypocretin, which promotes wakefulness and regulates REM sleep. Hypocretin levels are usually normal in people who have narcolepsy without cataplexy. Hypocretin is an important neurochemical in your brain that helps regulate wakefulness and REM sleep.

Research indicates a possible association with exposure to the H1N1 virus (swine flu) and a certain form of H1N1 vaccine that’s currently administered in Europe. It’s not yet known if the virus directly triggers narcolepsy or whether exposure to the virus increases the likelihood that someone will have narcolepsy.

In some cases, genetics may play a role.

Although the cause of narcolepsy is not completely understood, current research suggests that narcolepsy may be the result of a combination of factors working together to cause a lack of hypocretin.

These factors include:

• Autoimmune disorders. When cataplexy is present, the cause is most often the loss of brain cells that produce hypocretin. Although the reason for this cell loss is unknown, it appears to be linked to abnormalities in the immune system. Autoimmune disorders occur when the body’s immune system turns against itself and mistakenly attacks healthy cells or tissue. Researchers believe that in individuals with narcolepsy, the body’s immune system selectively attacks the hypocretin-containing brain cells because of a combination of genetic and environmental factors.

• Family history. Most cases of narcolepsy are sporadic, meaning the disorder occurs in individuals with no known family history. However, clusters in families sometimes occur—up to 10 percent of individuals diagnosed with narcolepsy with cataplexy report having a close relative with similar symptoms.

• Brain injuries. Rarely, narcolepsy results from traumatic injury to parts of the brain that regulate wakefulness and REM sleep or from tumors and other diseases in the same regions.

Groups of neurons in several parts of the brain interact to control sleep, and the activity of these neurons is controlled by a large number of genes. The loss of hypocretin-producing neurons in the hypothalamus is the primary cause of type 1 narcolepsy. These neurons are important for stabilizing sleep and wake states. When these neurons are gone, changes between wake, REM sleep, and non-REM sleep can happen spontaneously. This results in the sleep fragmentation and daytime symptoms that people with narcolepsy experience.

It remains unclear exactly why hypocretin neurons die. However, research increasingly points to immune system abnormalities. HLA—human leukocyte antigen—genes play an important role in regulating the immune system. This gene family provides instructions for making a group of related proteins called the HLA complex, which helps the immune system distinguish between good proteins from an individual’s own body and bad ones made by foreign invaders like viruses and bacteria. One of the genes in this family is HLA-DQB1. A variation in this gene, called HLA-DQB1*06:02, increases the chance of developing narcolepsy, particularly the type of narcolepsy with cataplexy and a loss of hypocretins (also known as orexins). HLA-DQB1*06:02 and other HLA gene variations may increase susceptibility to an immune attack on hypocretin neurons, causing these cells to die. Most people with narcolepsy have this gene variation and may also have specific versions of closely related HLA genes.

However, it is important to note that these gene variations are common in the general population and only a small portion of the people with the HLA-DQB1*06:02 variation will develop narcolepsy. This indicates that other genetic and environmental factors are important in determining if an individual will develop the disorder.

Narcolepsy follows a seasonal pattern and is more likely to develop in the spring and early summer after the winter season, a time when people are more likely to get sick. By studying people soon after they develop the disorder, scientists have discovered that individuals with narcolepsy have high levels of anti-streptolysin O antibodies, indicating an immune response to a recent bacterial infection such as strep throat. Also, the H1N1 influenza epidemic in 2009 resulted in a large increase in the number of new cases of narcolepsy. Together, this suggests that individuals with the HLA-DQB1*06:02 variation are at risk for developing narcolepsy after they are exposed to a specific trigger, like certain infections that trick the immune system to attack the body.

Prognosis of interrupted sleep disorder (narcolepsy)

Narcolepsy symptoms usually begin during the teen or young adult years. People who have narcolepsy may find it hard to function at school, work, home, and in social situations because of extreme tiredness.

Narcolepsy has no cure, but medicines, lifestyle changes, and other therapies can improve symptoms. Research is ongoing on the causes of narcolepsy and new ways to treat it.

Complication of interrupted sleep disorder (narcolepsy)

Narcolepsy may cause serious problems for you professionally and personally. Others might see you as lazy or lethargic. Your performance may suffer at school or work.

• Interference with intimate relationships

Extreme sleepiness may cause low sex drive or impotence, and people with narcolepsy may even fall asleep while having sex. Intense feelings, such as anger or joy, can trigger some signs of narcolepsy such as cataplexy, causing affected people to withdraw from emotional interactions.

• Physical harm

Sleep attacks may result in physical harm to people with narcolepsy. You’re at increased risk of a car accident if you have an attack while driving. Your risk of cuts and burns is greater if you fall asleep while preparing food.

• Obesity

People with narcolepsy are more likely to be overweight. The weight gain may be related to medications, inactivity, binge eating, hypocretin deficiency or a combination of factors.

How is interrupted sleep disorder diagnosed ?

A clinical examination and detailed medical history are essential for diagnosis and treatment of narcolepsy. Individuals may be asked by their doctor to keep a sleep journal noting the times of sleep and symptoms over a one- to two-week period. Although none of the major symptoms are exclusive to narcolepsy, cataplexy is the most specific symptom and occurs in almost no other diseases.

A physical exam can rule out or identify other neurological conditions that may be causing the symptoms. Two specialized tests, which can be performed in a sleep disorders clinic, are required to establish a diagnosis of narcolepsy:

Polysomnogram (PSG or sleep study). The Polysomnography is an overnight recording of brain and muscle activity, breathing, and eye movements. The test measures the electrical activity of your brain (electroencephalogram) and heart (electrocardiogram) and the movement of your muscles (electromyogram) and eyes (electro-oculogram). It also monitors your breathing. A polysomnogram can help reveal whether REM sleep occurs early in the sleep cycle and if an individual’s symptoms result from another condition such as sleep apnea.

Multiple sleep latency test (MSLT). The MSLT assesses daytime sleepiness by measuring how quickly a person falls asleep and whether they enter REM sleep. On the day after the polysomnogram, an individual is asked to take five short naps separated by two hours over the course of a day. If an individual falls asleep in less than 8 minutes on average over the five naps, this indicates excessive daytime sleepiness. However, individuals with narcolepsy also have REM sleep start abnormally quickly. If REM sleep happens within 15 minutes at least two times out of the five naps and the sleep study the night before, this is likely an abnormality caused by narcolepsy.

Hypocretin test. Occasionally, it may be helpful to measure the level of hypocretin in the fluid that surrounds the brain and spinal cord. To perform this test, a doctor will withdraw a sample of the cerebrospinal fluid using a lumbar puncture (also called a spinal tap) and measure the level of hypocretin-1. In the absence of other serious medical conditions, low hypocretin-1 levels almost certainly indicate type 1 narcolepsy.

What treatments are available for interrupted sleep disorder ?

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.

Medications

• Modafinil. The initial line of treatment is usually a central nervous system stimulant such as modafinil. Modafinil is usually prescribed first because it is less addictive and has fewer side effects than older stimulants. For most people these drugs are generally effective at reducing daytime drowsiness and improving alertness.

• Amphetamine-like stimulants. In cases where modafinil is not effective, doctors may prescribe amphetamine-like stimulants such as methylphenidate to alleviate EDS. However, these medications must be carefully monitored because they can have such side effects as irritability and nervousness, shakiness, disturbances in heart rhythm, and nighttime sleep disruption. In addition, health care professionals should be careful when prescribing these drugs and people should be careful using them because the potential for abuse is high with any amphetamine.

• Antidepressants. Two classes of antidepressant drugs have proven effective in controlling cataplexy in many individuals: tricyclics (including imipramine, desipramine, clomipramine, and protriptyline) and selective serotonin and noradrenergic reuptake inhibitors (including venlafaxine, fluoxetine, and atomoxetine). In general, antidepressants produce fewer adverse effects than amphetamines. However, troublesome side effects still occur in some individuals, including impotence, high blood pressure, and heart rhythm irregularities. Older antidepressants, such as protriptyline (Vivactil), imipramine (Tofranil) and clomipramine (Anafranil), are effective for cataplexy, but many people complain of side effects, such as dry mouth and lightheadedness.
• Selective serotonin reuptake inhibitors (SSRIs) or serotonin and norepinephrine reuptake inhibitors (SNRIs). Doctors often prescribe these medications, which suppress REM sleep, to help alleviate the symptoms of cataplexy, hypnagogic hallucinations and sleep paralysis. They include fluoxetine (Prozac, Sarafem, Selfemra) and venlafaxine (Effexor XR). Side effects can include weight gain, sexual dysfunction and digestive problems.

• Sodium oxybate (Xyrem). Sodium oxybate (also known as gamma hydroxybutyrate or GHB) has been approved by the U.S. Food and Drug Administration to treat cataplexy and excessive daytime sleepiness in individuals with narcolepsy. It is a strong sedative that must be taken twice a night (one at bedtime and one up to four hours later). Xyrem can have side effects, such as nausea, bed-wetting and worsening of sleepwalking. Taking sodium oxybate together with other sleeping medications, narcotic pain relievers or alcohol can lead to difficulty breathing, coma and death. Due to safety concerns associated with the use of this drug, the distribution of sodium oxybate is tightly restricted.

• Emerging treatments being investigated for narcolepsy include hypocretin replacement, hypocretin gene therapy and immunotherapy, but further research is needed before any may be available in clinical practice.

Lifestyle and Home remedies

Not everyone with narcolepsy can consistently maintain a fully normal state of alertness using currently available medications. Drug therapy should accompany various lifestyle changes. The following strategies may be helpful:

• Take short naps. Many individuals take short, regularly scheduled naps at times when they tend to feel sleepiest.
• Maintain a regular sleep schedule. Going to bed and waking up at the same time every day, even on the weekends, can help people sleep better.
• Avoid caffeine or alcohol before bed. Individuals should avoid alcohol and caffeine for several hours before bedtime.
• Avoid smoking, especially at night.
• Exercise daily. Exercising for at least 20 minutes per day at least 4 or 5 hours before bedtime also improves sleep quality and can help people with narcolepsy avoid gaining excess weight.
• Avoid large, heavy meals right before bedtime. Eating very close to bedtime can make it harder to sleep.
• Relax before bed. Relaxing activities such as a warm bath before bedtime can help promote sleepiness. Also make sure the sleep space is cool and comfortable.
• Safety precautions, particularly when driving, are important for everyone with narcolepsy. People with untreated symptoms are more likely to be involved in automobile accidents although the risk is lower among individuals who are taking appropriate medication. EDS and cataplexy can lead to serious injury or death if left uncontrolled. Suddenly falling asleep or losing muscle control can transform actions that are ordinarily safe, such as walking down a long flight of stairs, into hazards.

The Americans with Disabilities Act requires employers to provide reasonable accommodations for all employees with disabilities. Adults with narcolepsy can often negotiate with employers to modify their work schedules so they can take naps when necessary and perform their most demanding tasks when they are most alert. Similarly, children and adolescents with narcolepsy may be able to work with school administrators to accommodate special needs, like taking medications during the school day, modifying class schedules to fit in a nap, and other strategies.

Coping and support

Dealing with narcolepsy can be challenging. Making adjustments in your daily schedule may help. Consider these tips:

Talk about it. Tell your employer or teachers about your condition and work with them to find ways to accommodate your needs. This may include taking naps during the day, breaking up monotonous tasks, recording meetings or classes, standing during meetings or lectures, and taking brisk walks at various times throughout the day.

Working

People who have narcolepsy can work in almost any type of job, but some jobs may be better than others.

For example, a job with a flexible work schedule can make it easier to take naps when needed. A job in which you interact with your coworkers can help keep you awake. Jobs that don’t require you to drive or are closer to home also may better suit your needs.

Certain laws may apply to workers who have medical conditions, such as narcolepsy. These laws include the:

• Americans with Disabilities Act (ADA). The Americans With Disabilities Act prohibits discrimination against workers with narcolepsy and requires employers to provide reasonable accommodation to qualified employees. This law requires employers to reasonably accommodate the needs of their workers who have disabilities. This includes people who have narcolepsy. For example, employers may allow workers to take short naps during the workday or adjust work schedules to avoid sleepy periods.
• Family and Medical Leave Act. This law requires employers who have 50 or more employees to provide unpaid leave to employees who have an illness, such as narcolepsy. This law also gives leave to family members who need time to care for a close relative who has a serious illness.
• Social Security Disability Insurance or Supplemental Security Income programs. These programs may offer financial help if you can’t work because of your narcolepsy.

Be safe. If you must drive a long distance, work with your doctor to establish a medication schedule that ensures the greatest likelihood of wakefulness during your drive. Stop for naps and exercise breaks whenever you feel drowsy. Don’t drive if you feel your sleepiness is not well-controlled.

Driving can be dangerous for people who have narcolepsy. Ask your doctor whether you can drive safely. To help make it safer for you to drive:

• Take naps before driving. This helps some people who have periods of extreme daytime sleepiness.
• Stop often during long drives. Stretch and walk around during the stops.
• Try to have family, friends, or coworkers in the car to keep you aware and engaged, or get rides from them.

Emotional Issues and Support

Living with narcolepsy may cause fear, anxiety, depression, and stress. Talk about how you feel with your health care team. Talking to a professional counselor also can help. If you’re very depressed, your doctor may recommend medicines or other treatments that can improve your quality of life.

Joining a patient support group may help you adjust to living with narcolepsy. Support groups and counseling can help you and your loved ones cope with narcolepsy. Ask your doctor to help you locate a group or qualified counselor in your area. You can see how other people who have the same symptoms have coped with them. Talk with your doctor about local support groups or check with an area medical center.

Support from family and friends also can help relieve stress and anxiety. Let your loved ones know how you feel and what they can do to help you.

Additionally, support groups can be extremely beneficial for people with narcolepsy who want to develop better coping strategies or feel socially isolated due to embarrassment about their symptoms. Support groups also provide individuals with a network of social contacts who can offer practical help and emotional support.

1. What Is Narcolepsy? https://www.nhlbi.nih.gov/health/health-topics/topics/nar/[↩]
2. Narcolepsy Fact Sheet. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Narcolepsy-Fact-Sheet[↩]