CHAPTER 109

Sleep Disorders

Sleep disorders are disturbances that affect the ability to fall asleep, stay asleep, or stay awake or that cause abnormal behaviors during sleep, such as night terrors or sleepwalking.

Sleep can be disturbed by many factors, including irregular bed times, activities before bed, stress, diet, disorders, and drugs.

Lack of sleep makes people feel sleepy, tired, and irritable during the day and interferes with functioning.

Less often, a sleep disorder makes people unable to resist falling asleep during the day.

A detailed description of the problem, sometimes with information from a sleep log, usually indicates the diagnosis, but sometimes testing in a sleep laboratory is needed.

Sleep is necessary for survival and good health, but why sleep is needed and exactly how it benefits people are not fully understood. Individual requirements for sleep vary widely: usually from 6 to 10 hours every day. Most people sleep at night. However, many people must sleep during the day to accommodate work schedules—a situation that can lead to sleep disorders.

How long people sleep and how rested they feel after waking can be influenced by many factors, including level of excitement or emotional distress, age, diet, and use of drugs. For example, some drugs make people sleepy, and others make sleeping difficult. Some food components or additives, such as caffeine, strong spices, and monosodium glutamate (MSG), may disturb sleep. Older people tend to fall asleep earlier, to awaken earlier, and to be less tolerant of changes in sleep habits (for example, they may be more prone to jet lag and problems related to shift work). Compared with younger adults and children, older people are more easily aroused from sleep and awaken more often during the night. Whether older people need less sleep is unclear. They probably need as much sleep as younger people but do not sleep as well as they used to, leading to daytime sleepiness and napping. Napping during the day may help compensate for poor sleep during the night, but it may also contribute to the problem.

All sleep is not the same. There are two main types of sleep: rapid eye movement (REM) sleep and nonrapid eye movement (non-REM) sleep, which has four stages. People normally cycle through the four stages of non-REM sleep, usually followed by a brief interval of REM sleep, every 90 minutes or 5 or 6 times every night.

Non-REM sleep: Non-REM sleep accounts for about 75 to 80% of total sleep time in adults. Sleep progresses from stage 1 (the lightest level, when the sleeper can be awakened easily) to stage 4 (the deepest level, when the sleeper can be awakened with greater difficulty). In stage 4, blood pressure is at its lowest, and heart and breathing rates are at their slowest.

REM sleep: Electrical activity in the brain is unusually high, somewhat resembling that during wake-fulness. The eyes move rapidly, and muscles are paralyzed so that voluntary movement is impossible. However, some muscles may twitch involuntarily. The rate and depth of breathing increase.

The most vivid dreaming occurs during REM sleep. Most talking during sleep, night terrors, and sleepwalking occur during stages 3 and 4.

Symptoms

The most common symptoms are insomnia and excessive sleepiness during the day. People with insomnia have difficulty falling and staying asleep and wake up feeling unrefreshed. People with excessive daytime sleepiness tend to fall asleep during normal waking hours.

Some sleep disorders involve involuntary movements of the limbs or other unusual behaviors (such as nightmares) during sleep.

Other symptoms may include problems with memory, coordination, and emotions. People may perform less well in school or at their jobs. The risk of having a motor vehicle accident or developing a heart disorder is increased.

Diagnosis

Usually, sleep disorders can be diagnosed based on the medical history, including a description of the current problem, and results of a physical examination. Doctors ask for a detailed description of the problem and may ask people to keep a sleep log. In it, people record the following:

When they go to sleep

When they awaken in the morning

How many times they wake up during the night

How long they stay awake each time they wake up

What they do before going to bed

How they feel the next day (for example, whether they feel drowsy)

Whether they take any naps, at what time, and how long they last

SPOTLIGHT ON AGING

Up to half of older people say that they do not sleep as well as they would like. Although causes may be the same as for younger people, age-related changes may also contribute.

As people age, they may participate in fewer activities and become less physically active, making falling sleep harder. If people have to move into a relative’s home or a nursing home, they may have no control over such things as temperature and noise levels. The resulting discomfort can make sleeping more difficult.

If people go out less and spend less time outdoors, their exposure to sunlight is decreased. Exposure of the eyes to sunlight is necessary for the body to produce melatonin, a hormone that helps promote sleep. Also, the aging body produces less melatonin and growth hormone (which promotes deep sleep).

Usually, older people tend to fall asleep and wake up earlier. They may take longer to get to sleep. They also spend less time in deep sleep (which helps the body recover from daytime activities). Once asleep, they wake up more often and more easily. As a result, they feel less refreshed when they wake up, even though they may have spent a long time in bed.

Older people are more likely to have medical and emotional disorders that can interfere with sleep. Disorders interfere with sleep in several ways:

By causing pain (as occurs in arthritis)

By making people have to urinate more often, waking them up frequently during the night (as occurs in benign prostatic hyperplasia, diabetes, or heart failure)

By making breathing difficult (as occurs in heart or lung disorders)

Depression, which is common among older people, also interferes with sleep.

Older people are more likely to take drugs that affect sleep. Some (such as diuretics for heart failure) increase the need to urinate and thus interrupt sleep. Other drugs make people sleepy during the day or stimulate them. Either way, sleeping at night may be harder.

Older people tend to take naps because they do not sleep well during the night. Napping may be more likely because the aging body is less able to regulate blood pressure as needed. For example, after a big meal, blood pressure decreases, and the body needs to pump relatively more blood to the head. The aging body is less able to make this adjustment. As a result, older people feel sleepy.

Generally, older people need as much sleep as they did when they were young and should not accept poor sleep as part of aging. They can take measures to improve sleep. Staying active, spending time outside, avoiding foods and beverages (such as those that contain caffeine) that can interfere with sleep, going to bed at regular times, and making sure their bedroom is conducive to sleep can help.

When the diagnosis is uncertain or when doctors suspect certain types of sleep disorders, evaluation in a sleep laboratory may be recommended. The evaluation consists of polysomnography and observation and sometimes video recording of unusual movements during an entire night’s sleep. Polysomnography includes the following:

Electroencephalography (EEG), which records the brain’s electrical activity (see page 636)

Electrocardiography (ECG), which records heart rhythm and rate

Recording and monitoring of breathing functions

Electro-oculography, which records eye movement during REM sleep

Electromyography, which records muscle activity of the facial area and legs

Oximetry, which records oxygen levels in the blood with a painless ear clip or finger clip

Insomnia

Insomnia is difficulty falling asleep or staying asleep or a disturbance in sleep quality that makes sleep seem inadequate or unrefreshing.

People are sleepy and tired during the day and have trouble functioning.

Doctors base the diagnosis on a detailed description of sleep habits and patterns and sometimes use testing in a sleep laboratory.

If possible, the cause is corrected, sometimes with changes in lifestyle, but sleep aids may be needed.

Insomnia is usually a symptom that can have many different causes:

An irregular sleep-wake schedule

Poor sleep habits (for example, drinking a caffeinated beverage in the afternoon or evening or exercising late at night)

Physical disorders (such as those that cause pain or make people urinate more often)

Use or withdrawal of a drug

Drinking large amounts of alcohol in the evening

Emotional problems, anxiety, and stress

Stages of the Sleep Cycle

People normally cycle through distinct stages of sleep 4 or 5 times during the night. Relatively little time is spent in stage 1 (shallow) sleep. The greatest time is spent in stage 2 sleep. Deep sleep (stages 3 and 4) occurs mostly during the first half of the night, whereas more time is spent in rapid eye movement (REM) sleep as the night progresses. Brief awakenings occur throughout the night, most of which the sleeper is typically unaware of.

However, insomnia itself can be a disorder on its own. Some people have long-standing (chronic) insomnia that has little or no apparent relationship to any particular cause.

Difficulty falling and staying asleep and waking up earlier than desired are common among young and old. About 10% of adults have chronic insomnia, and about 50% have insomnia sometimes.

Because sleep patterns deteriorate as people age, older people are more likely to report insomnia than younger people. As people age, they tend to sleep less at night and to feel sleepier and to nap during the day. Stages 3 and 4 sleep, the periods of deep sleep that is most refreshing, become shorter and eventually disappear. Also, older people awaken more during all stages of sleep. Usually, these changes alone do not indicate a sleep disorder in the elderly.

There are several types of insomnia:

Difficulty falling asleep (sleep-onset insomnia): Commonly, people have difficulty falling asleep when they cannot let their minds relax and they continue to think and worry. Sometimes the body is not ready for sleep at what is considered a usual time for sleep. That is, the body’s internal clock is out of sync with the earth’s cycle of light and dark. This problem (a type of circadian rhythm sleep disorder) is common among adolescents and young adults.

Difficulty staying asleep (sleep maintenance insomnia): Older people are more likely to have difficulty staying asleep than are younger people. People with this type of insomnia fall asleep normally but wake up several hours later and cannot fall asleep again easily. Sometimes they drift in and out of a restless, unsatisfactory sleep.

Early morning awakening: This type may be a sign of depression in people of any age.

Symptoms and Diagnosis

Symptoms include irritability, fatigue during the day, and problems concentrating or performing under stress.

To diagnose insomnia, doctors ask people about their sleep patterns, habits around bedtime, use of drugs (including illicit drugs), use of other substances (such as alcohol, caffeine, and tobacco), degree of psychologic stress, medical history, and level of physical activity. People may be asked to keep a sleep log. In it, they record a detailed description of the sleep habits, including sleep and wake times, use of naps, and any problems with sleeping.

Science Wakes Up to Sleep Disorders

People with all types of sleep disorders are sent to sleep disorder specialists for evaluation, diagnosis, and treatment. Some people require testing in a sleep laboratory. The following symptoms may prompt such a referral:

Excessive daytime sleepiness

Long-standing (chronic) insomnia

Dependence on sleep aids

Pauses in breathing during sleep

Severe snoring or choking during sleep

Nightmares

Sleepwalking, talking during sleep, or violent movements during sleep

Twitching of the legs or arms during sleep

An irresistible urge to move the legs or arms just before or during sleep

An initial evaluation by a sleep disorders specialist may include the following:

A sleep history, often including a sleep log

A general medical history

A physical examination

After the initial evaluation, further testing, such as blood tests and sleep laboratory testing, may be done. Sleep laboratory testing includes overnight polysomnography and a multiple sleep latency test.

In overnight polysomnography, people spend the night in a sleep laboratory with electrodes pasted to their scalp, facial area, and chin. With this information, sleep stages can be characterized. Electrodes are also attached to other areas of the body to record heart rate and muscle activity. Other bodily functions, such as breathing pattern, are also monitored and recorded. Polysomnography is used to detect breathing disorders, epilepsy, and unusual movements and behaviors during sleep (periodic limb movement disorder and parasomnias).

In a multiple sleep latency test, people spend the day in a sleep laboratory, taking four or five naps at 2-hour intervals. This test is used to detect daytime sleepiness and to diagnose narcolepsy.

Some people need less sleep than others, so the diagnosis of insomnia is based on individual needs.

A physical examination is done to check for disorders that can cause insomnia. Occasionally, if insomnia persists despite measures to correct it, people may be referred to a sleep disorders specialist for evaluation and sometimes tests such as polysomnography. For this test, brain activity, heart rate, breathing, muscle activity, and eye movements are monitored while people sleep.

Treatment

The treatment of insomnia depends on its cause and severity. If insomnia results from another disorder, treatment of that disorder may improve sleep. For most people who have insomnia, some simple changes in lifestyle, such as following a regular sleep schedule and avoiding caffeine after lunch time, can improve sleep.

When a sleep disorder interferes with normal activities and a sense of well-being, taking sleep aids (also called hypnotics) occasionally for up to a few weeks may help. Most sleep aids require a prescription. Some are available without a prescription (over-the-counter, or OTC), but an OTC sleep aid may be no safer than a prescription sleep aid, especially for older people. OTC sleep aids contain diphenhydramine or doxylamine, both antihistamines, which may have side effects, such as drowsiness or sometimes nervousness, agitation, falls, and confusion, especially in older people. OTC sleep aids should not be taken for more than 7 to 10 days. They are intended to manage an occasional sleepless night, not chronic insomnia, which could signal a serious underlying problem.

Did You Know…

Almost half of people have insomnia at one time or another.

Taking a prescription sleep aid may be safer than taking one sold over the counter.

For people with insomnia related to a “stressed mind,” the most effective and safest treatment is usually talk therapy, done by trained specialists. This approach helps people understand the problem, unlearn bad sleeping habits, and eliminate unhelpful thoughts, such as worry about losing sleep or the next day’s activities. Older people who have interrupted sleep can benefit from regular bedtimes, lots of environmental light exposure during the day, regular exercise, and less napping during the day because napping may make getting a good night’s sleep even harder. Many older people with insomnia do not need to take sleep aids. But if they do, they should keep in mind that these drugs can cause problems. Thus, caution is required.

People who have insomnia and depression should be evaluated by a doctor, and the depression should be treated. Treating depression often relieves the insomnia, but some antidepressants can improve sleep directly because they have sedating effects. Usually, the antidepressant relieves depression but does not improve sleep. Then doctors may prescribe a sleep aid in addition.

Ways to Improve Sleep

Follow a regular sleep schedule: People should go to bed at the same time each night and, more importantly, get up at the same time each morning, even on weekends and vacations.

Follow a bedtime routine: A regular pattern of activities—such as walking at a relaxed pace, listening to soft music, brushing the teeth, washing the face, and setting the alarm clock—can set the mood for sleep. This routine should be followed every night, at home or away.

Make the environment conducive to sleep: The bedroom should be kept dark, quiet, and not too warm or too cold. Loud noises can disturb sleep even when people are not awakened by them. Wearing ear plugs, using a white-noise machine or a fan, or installing heavy curtains in the bedroom (to block out outside noises) can help.

Use the bedroom primarily for sleeping: The bedroom should not be used for eating, reading, watching television, paying bills, or other activities associated with wakefulness (other than intimate activity).

Avoid substances that interfere with sleep: Food and beverages that contain alcohol or caffeine (such as coffee, tea, cola drinks, and chocolate) can interfere with sleep, as can appetite suppressants, diuretics, and nicotine (in cigarettes and nicotine patches). Caffeinated substances should not be consumed within 12 hours of bedtime. Drinking a large amount of alcohol in the evening causes early morning awakenings. Quitting smoking may help.

Use pillows: Pillows between the knees or under the waist can make people more comfortable. For people with back problems, lying on the side with a large pillow between the knees may help.

Get up: When falling asleep is difficult, getting up and doing something else in another room and coming back to bed when sleepy may be more effective than lying in bed and trying harder and harder to fall asleep.

Exercise regularly: Exercise can help people fall asleep naturally. However, exercise within 5 hours of bedtime can stimulate the heart and brain and keep people awake.

Relax: Stress and worry are major impediments to sleep. People who are not sleepy at bedtime can relax by reading or taking a warm bath. People can aim to leave their problems at the bedroom door. Avoiding too much mental stimulation during the hour or so before bedtime can help. Scheduling a “worry time” during the day to think about concerns can diminish the need to worry at bedtime.

Eat a light snack: Hunger can interfere with going to sleep. A light snack, especially if warm, can help, unless a person has gastroesophageal reflux (GERD). However, heavy meals near bedtime should be avoided. They may cause heartburn, which can interfere with sleep.

Eliminate behavior that provokes anxiety: Turn the clock away so that time is not a focus.

Melatonin (see page 2077) is sometimes used to treat insomnia, especially in older people, who may have low levels of melatonin. However, its use is controversial. Melatonin appears to be safe for short-term use (up to a few weeks), but the effects of using it for a long time are unknown. Many other medicinal herbs and dietary supplements, such as skullcap and valerian, are available in health food stores, but their effects on sleep and side effects are not well understood.

Circadian Rhythm Sleep Disorders

Circadian rhythm sleep disorders occur when people’s internal sleep-wake schedule (clock) does not align with the earth’s cycle of darkness (night) and light (day).

Jet lag and shift work commonly disturb the usual rhythms of sleep and waking.

People cannot awaken or go to sleep when they need or want to.

Doctors base the diagnosis on symptoms, sometimes using information from a sleep log and sleep laboratory testing.

Good sleep habits and exposure to bright light can help people readjust their sleep-wake cycle.

Circadian means around (circa) the day (dies). Circadian rhythms are the regular changes in mental and physical states that occur in about a 24-hour period—a person’s internal clock. These rhythms are controlled by an area of the brain that is influenced by light (called the circadian pacemaker). After entering the eye, light stimulates cells in the back of the eye (retina) to send nerve impulses to this area. These impulses signal the brain to stop producing melatonin, a sleep-promoting hormone.

Normally, people vary in their sleep and wake times. Some (morning people or larks) prefer to sleep and wake early. Others (night people or owls) prefer to sleep and wake late. Such variations are not considered a disorder as long as people can do the following:

Wake up when they need to do something in the morning and fall asleep the night before in time to get enough sleep before having to get up

Sleep and wake up at the same time every day, if they want to

Adjust to new sleep and wake times within a few days after they start a new routine

People with a circadian rhythm sleep disorder fall asleep at inappropriate times and then cannot sleep or wake up when they need or want to. Their sleep-wake cycle is disrupted.

Causes

Causes may be internal or external. Internal causes include damage to the brain (for example, due to brain infection (encephalitis), stroke, head injury, or Alzheimer’s disease) and insensitivity to the cycle of night and day.

Sleep Aids: Not to Be Taken Lightly

Among the most commonly used sleep aids are sedatives, minor tranquilizers, and antianxiety drugs. Most are safe as long as a doctor supervises their use.

Most sleep aids require a doctor’s prescription because they may cause problems. Many of these problems are less common with newer sleep aids.

Loss of effectiveness: Once people become accustomed to a sleep aid, it may become ineffective. This effect is called tolerance.

Withdrawal symptoms: If a sleep aid is taken for more than a few days, stopping it can make the original sleep problem suddenly worse (causing rebound insomnia) and can increase anxiety. Thus, doctors recommend reducing the dose slowly over a period of several weeks until the drug is stopped.

Habit-forming or addiction potential: People who use sleep aids for more than a few days may feel that they cannot sleep without them. Stopping the drug makes them anxious, nervous, and irritable or causes disturbing dreams.

Potential for overdose: If taken in higher than recommended doses, some of the older sleep aids can cause confusion, delirium, dangerously slow breathing, a weak pulse, blue fingernails and lips, and even death.

Serious side effects: Most sleep aids, even when taken at recommended doses, are particularly risky for older people and for people with breathing problems because they tend to suppress areas of the brain that control breathing. Some can reduce daytime alertness, making driving or operating machinery hazardous. Sleep aids are especially dangerous when taken with alcohol, opioids (narcotics), antihistamines, or antidepressants because these drugs also cause daytime drowsiness and can suppress breathing. The combined effects are more dangerous. Rarely, especially if taken at higher than recommended doses or with alcohol, sleep aids have been known to cause people to walk or even drive during sleep and to cause severe allergic reactions.

Newer sleep aids can be used for longer periods of time without losing effect, becoming habit-forming, or causing withdrawal. They are also less dangerous in an overdose.

Benzodiazepines are the most commonly used sleep aids. Some benzodiazepines (such as chlordiazepoxide, diazepam, flurazepam, and nitrazepam) are longer acting than others (such as temazepam and triazolam). Doctors try to avoid prescribing long-acting benzodiazepines for older people. Older people cannot metabolize and excrete drugs as well as younger people. Thus for them, taking these drugs may be more likely to cause daytime drowsiness, slurred speech, and falls.

Other useful sleep aids are not benzodiazepines, but work at the same brain areas as the benzodiazepines. These drugs (eszopiclone, zolpidem, and zaleplon) are shorter acting than most of benzodiazepines and are less likely to lead to daytime drowsiness. Older people appear to tolerate these drugs well. There is also a longer-acting (extended-release, or ER) version of zolpidem. Ramelteon, a newer sleep aid, has the same advantages as these shorter-acting drugs. In addition, it can be used longer than benzodiazepines without losing its effectiveness or causing withdrawal symptoms. It is not habit-forming and does not appear to have overdose potential. Ramelteon affects the same area of the brain as melatonin (a hormone that helps promote sleep) and is thus called a melatonin receptor agonist.

Some antidepressants (most commonly trazodone) can relieve insomnia and prevent early morning awakening, but side effects, such as daytime sleepiness, can be a problem, especially for older people. Low doses are used to treat insomnia unless it is caused by depression. Then, higher doses, usually used to treat depression, are used.

Diphenhydramine and dimenhydrinate are two inexpensive over-the-counter antihistamines that can relieve occasional or mild sleeping problems. However, they are not the best sleep aids, and they may have side effects, including daytime sleepiness, confusion, and urinary difficulties, especially in older people.

External causes include the following:

Jet lag (especially when traveling from west to east)

Working irregular shifts or a regular basis

Frequently going to bed and getting up at different times

Being confined to bed for a long time

Blindness and not being exposed to sunlight for long periods of time

Taking certain drugs

Sleep-wake reversals are common among people who are hospitalized because they are often awakened during the night and because their eyes are not exposed to sunlight long enough during the day.

There are several types of circadian rhythm disorders.

Jeg lag disorder is caused by rapid travel across > 2 time zones.

Shift work disorder varies in severity depending on how often shifts change, how much they change, and whether they make sleep and wake times earlier or later. Always working night or evening shifts and keeping the same bed times on days off is preferable. However, even then, daytime noise and light may interfere with sleep. Also, workers often shorten their sleep time and sleep at different times on days off to participate in social or family events.

Delayed sleep phase syndrome occurs when people consistently go to sleep and awaken late (for example, go to sleep at 3 AM and wake up at 10 AM or as late as 1 PM). This syndrome is more common among adolescents and young adults. People with this syndrome cannot fall asleep earlier even if they try.

Advanced sleep phase syndrome occurs when people consistently go to bed and awaken early. It is more common among older people. People with this syndrome cannot stay awake until later times even if they try.

Non-24-hour sleep-wake syndrome occurs when the sleep-wake cycle changes every day. Sleep and wake times vary by 1 to 2 hours each day. This syndrome is much less common and tends to occur in blind people.

Symptoms

Because people cannot sleep when they need to, they may be sleepy during the day and have difficulty concentrating, thinking clearly, and doing their usual activities. They may misuse alcohol, sleep aids, and stimulants in an effort to sleep or stay awake.

Symptoms may be worse when people change their sleep schedule frequently, as when they frequently travel across several time zones or change their shift at work. Symptoms are also worse if the change makes wake and sleep times earlier (advances the sleep cycle) because delaying sleep is easier than going to sleep earlier. The sleep cycle is advanced when people fly east or when shifts change from days to nights to evenings.

If the cause is external, the timing of other circadian body rhythms, including temperature and hormone secretion, is affected. Thus, people may feel generally unwell, irritable, nauseated, and depressed, as well as sleepy.

If the cause of the disruption can be corrected, symptoms resolve over several days as rhythms readjust. In older people, resolution may take a few weeks or months.

Diagnosis

Doctors suspect the diagnosis based on symptoms. People are usually asked to keep a sleep log and to record their sleep and wake times for a week or two. Testing in a sleep laboratory is rarely needed.

Treatment

Developing good sleep habits can help (see box on page 670).

Exposure of the eyes to bright light at appropriate times may be the most helpful strategy. Such exposure helps reset the internal clock. For example, travelers should spend time in sunlight, particularly in the morning, after they reach their destination (see page 2103). Shift workers should spend time in bright light (sunlight or artificial light) at times when they should be awake. While they are asleep, they should make the bedroom as dark and quiet as possible. Sleep masks and white-noise devices can be used. Exposure to bright light in the morning may help people with delayed sleep syndrome. Bright light in the evening may help people with advanced sleep syndrome.

Another strategy is to gradually shift the sleep-wake schedule to the one that is desired. Travelers may benefit from gradually shifting their schedule to approximate that of their destination, beginning well ahead of travel time.

If symptoms persist, sleep aids with effects that last only a short time (short-acting drugs) and drugs that stimulate the brain (such as modafinil) may help people sleep better and feel more alert during the day. However, these drugs do not adjust the body rhythms any faster.

Melatonin may help minimize the effects of jet lag and problems related to working shifts. However, its use is controversial. Melatonin appears to be safe for short-term use (up to a few weeks), but the effects of using it for a long time are unknown.

Hypersomnia and Excessive Daytime Sleepiness

Hypersomnia is a substantial increase in total sleeping time. Excessive daytime sleepiness (EDS) is the inability to stay awake and alert during the day, resulting in unintended lapses into drowsiness or sleep.

Hypersomnia, which is less common than insomnia, refers to an increase of at least 25% in total sleeping time that continues for more than a few days. EDS refers to a condition in which people are abnormally sleepy during the day. They may fall asleep while they are driving or working. In some disorders, such as narcolepsy, hypersomnia and EDS occur together in the same person. In other disorders, such as sleep deprivation, the two do not occur together.

Being unusually sleepy and falling asleep unintentionally after a period of sleep deprivation is not hypersomnia. In such cases, extra sleep is a desired response. However, hypersomnia and EDS in people who have not previously curtailed their sleep may indicate a serious disorder, such as the following:

A brain or nerve (neurologic) disorder, including encephalitis, meningitis, and brain tumor

A heart or lung disorder

Liver failure

Sleep apnea syndrome

Narcolepsy

Severe anxiety

Depression, especially in people with bipolar disorder

A disorder of the nerves that affect the muscles of legs or arms, which disrupts the refreshing quality of sleep

Chronic hypersomnia that begins during adolescence may be a symptom of narcolepsy. Hypersomnia may also result from overuse of sleep aids and other drugs that cause drowsiness.

Diagnosis

When evaluating people who have become excessively sleepy, doctors ask about their mood, sleep-wake schedule, use of drugs, and any abnormalities that occur during sleep. These abnormalities may include snoring and breathing pauses (which suggest obstructive sleep apnea), as well as grinding of teeth and kicking during sleep. Often, a sleep partner can describe the sleep abnormalities best. Doctors also do a physical examination.

Depending on other symptoms and the results of the physical examination, doctors may evaluate the heart, lungs, and liver to determine whether a disorder is causing hypersomnia. A neurologic examination may also be necessary (see page 630). It may detect impaired memory or other problems suggesting a neurologic disorder. If a neurologic disorder is suspected, computed tomography (CT) or magnetic resonance imaging (MRI) is done, and the person is referred to a neurologist. In many cases, people with hypersomnia and EDS require polysomnography with or without multiple sleep latency testing to establish the proper diagnosis.

Treatment

The treatment of hypersomnia with or without EDS depends on the underlying diagnosis. If doctors determine that the person has “idiopathic hypersomnia,” that is, hypersomnia without a specific underlying cause, they often recommend proper sleep habits and regular naps. In more severe cases, stimulant drugs, such as modafinil and sometimes amphetamine, dextroamphetamine, or methylphenidate, are used to help reduce the sleepiness. If EDS and hypersomnia are caused by another condition, such as sleep apnea syndrome, a brain infection, or depression, that condition is treated.

Narcolepsy

Narcolepsy is a sleep disorder marked by excessive sleepiness during the day or recurring, uncontrollable episodes of sleep during normal waking hours, plus sudden episodes of muscle weakness (cataplexy). Sometimes sleep paralysis, vivid dreams, and hallucinations while falling asleep or waking up from sleep also occur.

Testing in a sleep laboratory, with polysomnography and multiple sleep latency testing, is needed to confirm the diagnosis.

Drugs are used to help keep people awake and to control other symptoms.

Narcolepsy occurs in about 1 of 2,000 people in the US and Europe. In some cases, the disorder tends to run in families, but its cause is unknown. Although narcolepsy has no serious medical consequences, it can be disabling and increases the risk of motor vehicle and other accidents. Narcolepsy persists throughout life but does not affect life expectancy.

Narcolepsy reflects, in part, abnormalities in the timing and control of rapid eye movement (REM) sleep. Many symptoms resemble what happens during REM sleep. The muscle weakness, sleep paralysis, and hallucinations of narcolepsy resemble the loss of muscle tone, paralysis, and vivid dreaming that occurs during REM sleep.

Symptoms

Symptoms usually begin during adolescence or young adulthood and persist throughout life. Only about 10% of people with narcolepsy have all the symptoms. Most people have only a few. All have excessive daytime sleepiness (EDS).

EDS has been going on for a long time, often despite long periods of excessive sleep. Many people are overcome by sudden episodes of uncontrollable sleep that can occur at any time, often without warning (called sleep attacks). Falling asleep can be resisted only temporarily. People may have many episodes or only a few in a single day. Each usually lasts a few minutes or less but may last hours. Patients typically feel refreshed upon awakening even if the sleep episode lasts a few minutes. Episodes are most likely to occur in monotonous situations, as during boring meetings or long periods of highway driving. When intentionally taking short naps, people dream vividly. Nighttime sleep may be unsatisfying and interrupted by periodic awakenings and vivid, frightening dreams.

While people are awake, during the day, a sudden episode of muscle weakness without loss of consciousness—called cataplexy—may be triggered by a sudden emotional reaction such as anger, fear, joy, laughter, or surprise. People may become limp, drop something being held, or fall to the ground. These episodes resemble the normal muscle paralysis that occurs during rapid eye movement (REM) sleep and, to a lesser degree, the experience of being “weak with laughter.” Cataplexy occurs in about 3 of 4 people with narcolepsy.

Occasionally, when just falling asleep or immediately after awakening, people try to move but cannot. This experience, called sleep paralysis, can be terrifying. The touch of another person may relieve the paralysis. Otherwise, the paralysis disappears on its own after several minutes.

When just falling asleep or, less often, when awakening, people may clearly see images or hear sounds that are not there. These extremely vivid hallucinations are similar to those of normal dreaming but are more intense. Hallucinations are called hypnagogic when they occur before falling asleep or hypnopompic when they occur before awakening.

People are less able to function and concentrate. They may lose their motivation and become depressed. Family and other relationships may be hurt.

Diagnosis

Doctors cannot base the diagnosis on symptoms alone because other disorders can cause some of the same symptoms. Sleep paralysis and similar hallucinations occasionally occur in otherwise healthy adults, in people who have been sleep deprived, and in people with sleep apnea syndrome or depression. These symptoms may also occur when certain drugs are taken. Therefore, testing in a sleep laboratory is necessary. Polysomnography is done overnight, and multiple sleep latency testing is done the next day. These tests involve monitoring and recording the activity of the brain, heart, breathing, muscles, and eyes. Various other body functions, including movement of the limbs, are also monitored and recorded.

Usually, narcolepsy does not result from abnormalities that can be detected by imaging procedures, such as computed tomography (CT) or magnetic resonance imaging (MRI).

Treatment

There is no cure for narcolepsy. However, for many people, continued treatment results in normal lives. People should also try to get enough sleep at night and take brief naps (< 30 min) at the same time every day (typically afternoon). If symptoms are mild, these measures may be all that is needed. For others, drugs that help keep people awake, such as modafinil (or sometimes dextroamphetamine or methylphenidate), are used to help reduce the sleepiness. The dose of these drugs may have to be adjusted to prevent side effects such as jitteriness, overactivity, nausea, headache, or weight loss. Doctors monitor people closely during drug treatment. Dextroamphetamine and methylphenidate are stimulants, which may cause agitation, high blood pressure, a fast heart rate, and moodiness. These drugs may also be habit-forming. Modafinil, which works in a different way, may have fewer side effects than the other drugs, although it also can be habit-forming.

Sodium oxybate, a drug taken while in bed and again during the night, can usually lessen excessive daytime sleepiness and cataplexy. Side effects include nausea, vomiting, dizziness, and sleepiness.

An antidepressant such as clomipramine or protriptyline usually helps relieve cataplexy, hallucinations, and sleep paralysis.

Periodic Limb Movement Disorder and Restless Legs Syndrome

Periodic limb movement disorder involves repetitive movements of the arms, legs, or both during sleep. Restless legs syndrome involves an irresistible urge to move and usually abnormal sensations in the legs, arms, or both when people sit still or lie down.

In people with periodic limb movement disorders, the legs, arms, or both twitch and jerk, disrupting sleep.

People with restless legs syndrome have trouble relaxing and sleeping because they cannot sit or lie still.

Doctors may diagnose restless legs syndrome based on symptoms, but testing in a sleep laboratory is needed to diagnose periodic limb movement disorder.

There is no cure, but drugs used to treat Parkinson’s disease and other drugs may help control symptoms.

These disorders are more common during middle and older age. Restless legs syndrome probably affects 1 to 2% of people. It is particularly common among people older than 50. Most people with restless legs syndrome also have periodic limb movement disorder, but the reverse is not true.

What causes these disorders is unknown. But one third or more of people with restless legs syndrome have family members with the syndrome. Risk factors include a sedentary lifestyle, smoking, and obesity. Periodic leg movement disorder is common among people with narcolepsy and rapid eye movement (REM) behavior disorder. Both disorders are more likely in people who have or do the following:

Stop taking certain drugs (including benzodiazepines such as diazepam)

Take stimulants (such as caffeine or stimulant drugs) or certain antidepressants

Have iron deficiency

Have anemia

Are pregnant

Have a kidney or liver disorder

Symptoms

Both disorders interrupt sleep. As a result, people feel tired and sleepy during the day.

In periodic limb movement disorder, the legs or arms typically twitch and jerk every 20 to 40 seconds during sleep. People are unaware of these movements and the brief awakenings that follow. People do not have any abnormal sensations in their legs or arms.

Typically, people with restless legs syndrome have an irresistible urge to move their legs when they are sitting still or lying down. People also often feel vague but intense strange sensations in their legs, sometimes accompanied by pain. The sensations may be described as burning, creeping, or tugging or like insects crawling inside the legs. Walking or moving or stretching the legs can relieve the sensations. People may pace, constantly move their legs while they are sitting, and toss and turn in bed. Thus, people have difficulty relaxing and falling asleep. During sleep, the legs may move spontaneously and uncontrollably, often awakening the sleeper. Symptoms are more likely to occur when people are under stress. Episodes may occur occasionally, causing few problems, or several times a week, depriving people of sleep and making it difficult to concentrate and function.

Diagnosis

Doctors can often diagnose restless legs syndrome based on symptoms reported by the person or the person’s bed partner. Polysomnography, including electromyography (EMG), is always done to diagnose periodic limb movement disorder. These tests are done overnight. In polysomnography, brain activity, heart rate, breathing, muscle activity, and eye movements are monitored while people sleep. People may be videotaped during an entire night’s sleep to document limb movements.

If either disorder is diagnosed, blood and urine tests are done to check for disorders that can contribute, such as anemia, iron deficiency, and kidney and liver disorders.

Treatment

Avoiding caffeine, which can make symptoms worse, is recommended. Taking vitamin and mineral supplements that contain iron may help.

There is no cure for these disorders, but certain drugs can help control symptoms.

Drugs used to treat Parkinson’s disease: Pramipexole or ropinirole may help (see table on page 774). These drugs imitate the actions of a neurotransmitter called dopamine. They increase nerve impulses to muscles. These drugs have relatively few side effects but can cause symptoms to occur earlier in the day or to worsen when the drug’s effect wears off or the drug is stopped. These drugs can also cause nausea and insomnia. Levodopa-carbidopa is sometimes used.

Benzodiazepines: These drugs (such as clonazepam) cause drowsiness, helping people sleep. These drugs may improve the quality of sleep. They are taken in low doses at bedtime. Over time, they may become less effective as people become accustomed to their effects. The drugs may also make people sleepy during the day.

Anticonvulsants: Gabapentin or carbamazepine (see table on page 716) is effective in some people.

Opioids: An opioid such as oxycodone may be used as a last resort because they can have serious side effects, including the possibility of addiction.

Parasomnias

Parasomnias are unusual behaviors that occur during sleep.

Various unconscious and largely unremembered behaviors can occur during sleep in children and adults. Just before falling asleep, almost all people occasionally experience brief, involuntary jerks of the arms or the entire body. Occasionally, the legs jerk. Some people also experience sleep paralysis (attempting but being unable to move) or brief fleeting images or thoughts when they are just falling asleep or awakening. People may clench or grind their teeth or have nightmares. Sleepwalking, head-banging, and night terrors are more common among children and can be very distressing for their parents. Usually, children do not remember these episodes.

Night terrors are frightening episodes which result in sitting up, screaming, and flailing about. The eyes are wide open, and the heart races. Episodes usually occur during nonrapid eye movement (non-REM) stages of sleep, typically in the first few hours of the night. Night terrors are more common among children. Children should not be awakened because doing so makes them even more frightened. Although children appear to be highly distressed, they have no memory for the events or mental images after awakening and do not suffer psychologic problems as a result of these behaviors. Parents need not be overly distressed. Children usually stop having episodes when they become older. Episodes in adults are often associated with psychologic problems. Treatment with certain benzodiazepines, such as clonazepam, or tricyclic antidepressants, such as imipramine, may help. Adults may benefit from psychotherapy or drug treatment.

Nightmares are vivid, frightening dreams, followed by sudden awakening. Children and adults may have nightmares. Nightmares occur during rapid eye movement (REM) sleep. They are more likely to occur when people are under stress, have a fever, are excessively tired, or have consumed alcohol. Treatment, if necessary, focuses on the underlying problem.

Sleepwalking (somnambulism), most common in late childhood and adolescence, is walking in a semiconscious manner without being consciously aware of it. It occurs during the deepest stages of sleep. People do not dream while sleepwalking—in fact, brain activity during sleepwalking, although abnormal, is more like that of a wakeful state than of a sleeping one. Sleepwalkers may mumble repetitiously and can hurt themselves by walking into obstacles. Most sleepwalkers have no memory of sleepwalking.

No specific treatment is available, but the sleepwalker can be gently led back to bed. Leaving a light on in the bedroom or adjacent hall sometimes reduces the tendency to sleepwalk. Forcibly awakening the sleepwalker may provoke an agitated reaction and is not advised. Obstacles or breakable objects in the sleepwalker’s potential path should be removed, and windows should be kept closed and locked. Benzodiazepines, particularly diazepam and clonazepam, may help.

Rapid eye movement behavior disorder involves speaking (often profanely) and sometimes making violent movements during REM sleep, usually in response to a dream. Unlike night terrors, people with rapid eye movement behavior disorder are sometimes aware of having dreamed vividly during these episodes when they wake up the next day. Violent movements may include waving the arms, punching, and kicking. The violent behavior is not intentional and is not directed at anyone. The disorder is more common among the elderly, particularly those who have disorders that cause degeneration of the brain (such as Parkinson’s disease or Alzheimer’s disease). People may inadvertently injure themselves or their bed partner. Also, this behavior interferes with sleep, making people tired and sleepy during the day. Doctors can often diagnose this disorder based on symptoms reported by the person or the person’s bed partner. But if they cannot, polysomnography with electromyography (EMG) is usually done.

There is no cure for the disorder. But clonazepam, a benzodiazepine (which is a sedative), relieves symptoms in most people. A low dose is effective. The drug is usually continued indefinitely. Bed partners should be warned about the possibility of harm and may wish to sleep in another bed until the drug begins to work. People with the disorder should remove sharp objects and furniture from next to their bed.

Sleep Disorders in Dementia

In people with dementia (see page 688), such as Alzheimer’s disease, sleep patterns are often abnormal. As dementia progresses, the time spent in light sleep increases, so people are easily awakened.

People with dementia may have disorders that contribute to sleep problems. Disorders such as arthritis, dehydration, and infections may cause pain or discomfort, interfering with sleep. Use of certain drugs or interactions between drugs may also interfere with sleep.

Treatment of the underlying disorder may help improve sleep. Naps during the day are not helpful because they may make sleeping at night more difficult. Walking outside in the sunshine, keeping the temperature in the bedroom comfortable, and not consuming beverages or foods that contain caffeine during the evening may help.