Sleep Disorders - Neurology Channel

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Overview, Stages of Sleep

Overview
Sleep is absolutely essential for normal, healthy function. Scientists and medical professionals do not fully understand this complicated, necessary, physiological phenomenon. According to the National Institute of Neurological Disorders and Stroke, about 40 million people in the United States suffer from chronic long-term sleep disorders each year and an additional 20 million people suffer occasional sleep problems.

There are more than 70 different sleep disorders that are generally classified into one of three categories:

* lack of sleep (e.g., insomnia),
* disturbed sleep (e.g., obstructive sleep apnea), and
* excessive sleep (e.g., narcolepsy).

In most cases, sleep disorders can be easily managed once they are properly diagnosed. Insomnia is the most common sleep disorder. It occurs more often in women and in the elderly.

The amount of sleep that a person needs to function normally depends on several factors (e.g., age). Infants sleep most of the day (about 16 hours); teenagers usually need about 9 hours a day; and adults need an average of 7 to 8 hours a day. Although elderly adults require about as much sleep as young adults, they usually sleep for shorter periods and spend less time in deep stages of sleep. About 50% of adults over the age of 65 have some type of sleep disorder, although it is not clear whether this is a normal part of aging or a result of medications that older people commonly use.

Falling asleep and waking up are controlled by various chemical changes in the brain and in the blood. Foods and medicines that alter the balance of these chemicals also affect how well we sleep. Caffeine, for example, can cause insomnia (lack of sleep). Antidepressants can cause a loss of REM (rapid eye movement) sleep, as can smoking and alcohol. Smoking and alcohol also can result in a loss of deep sleep. Both REM and deep sleep are essential parts of the normal sleep cycle.

What is Sleep?
Sleep is a dynamic process during which the brain is very active. There are recognized stages of sleep, each of which is characterized by a different type of brain wave activity.

Stages of Sleep
There are five stages of sleep that cycle over and over again during a single night's rest: stages 1, 2, 3, 4 and REM (rapid eye movement). Stages 1 through 4 are also known as non-rapid eye movement sleep (NREM). About 50% of sleep time is spent in stage 2 and about 20% is spent in REM (normally more than 2 hours a night in adults). A complete sleep cycle, from the beginning of stage 1 to the end of REM, usually takes about an hour and a half.

Stage 1 is light sleep during which the muscles begin to relax and a person can be easily awakened. During stage 2, brain activity slows down and eye movement stops. Stages 3 and 4 comprise deep sleep, during which all eye and muscle movement ceases. It can be difficult to wake a person during deep sleep. Stage 3 is characterized by very slow brain waves (delta waves), interspersed with small, quick waves. In stage 4, the brain waves are all delta waves.

It is during deep sleep that some people sleepwalk and children may experience bedwetting. It is during REM sleep that dreams occur. The muscles of the body stiffen, the eyes move, the heart rate increases, breathing becomes more rapid and irregular, and the blood pressure rises.

Why Does the Body Need Sleep?
It is not clear exactly why the body requires sleep, although inadequate sleep can have severe detrimental effects on health. Studies have shown that sleep is essential for normal immune system function and to maintain the ability to fight disease and sickness. Sleep also is essential for normal nervous system function and the ability to function both physically and mentally. In addition, sleep is essential for learning and for normal, healthy cell growth.

Types

Sleep disorders are classified into three major categories: lack of sleep (e.g., insomnia), disturbed sleep (e.g., sleep apnea, REM sleep behavior disorder, restless leg syndrome and periodic limb movement disorder), and excessive sleep (e.g., narcolepsy).

Lack of Sleep
Insomnia is the inability to fall asleep. It is a common sleep problem that most people experience at least occasionally. When it occurs, people feel tired much of the time and often worry a lot about not getting enough sleep. Consequently, insomnia often disrupts daily life.

It can result from the following:

* Diet (e.g., intake of caffeine or alcohol)
* Emotional difficulties
* Stress
* Underlying disease

It also can be caused by other factors. For short-term insomnia, sleeping pills can be effective. For long-term insomnia, however, sleeping pills can actually worsen the condition.

Sleep deprivation is not actually a disorder; it simply indicates that a person has not been getting enough sleep. Inadequate sleep can affect judgment, reaction-time, hand-eye coordination, memory, and general well-being.

Studies have shown that sleep deprivation also can damage the immune system. Feeling drowsy during the day, falling asleep for very short periods of time (5 minutes or so), or regularly falling asleep immediately after lying down may indicate sleep deprivation.

Disturbed Sleep
Sleep apnea is interrupted breathing during sleep. It usually occurs because of a mechanical problem in the windpipe, but it also can indicate a neurological disorder involving nerve cells (neurons). As people age, muscle tone relaxes, which may cause the windpipe to collapse. This condition, called obstructive sleep apnea, results in loud snoring and blocked air flow through the windpipe that lasts from 10 to 60 seconds. It may appear that the person is gasping or snorting. When this occurs, the brain quickly reacts to the sudden lack of oxygen, the muscles tighten, and the windpipe opens.

Narrow nasal passages, enlarged tonsils, and obesity are factors that may contribute to obstructive sleep apnea. The condition may also be related to the use of alcohol, tobacco, or sedatives.

Patients with sleep apnea lose sleep because every time the windpipe closes, the person has to wake up enough to contract those muscles and resume breathing. As a result, the sleep cycle can be interrupted as many as 100 times a night. In addition, every time the windpipe closes, the brain is deprived of oxygen. This lack of oxygen eventually can cause problems morning headaches and decreased mental function. People who have sleep apnea are at increased risk for heart disease and stroke.

REM sleep behavior disorder causes disruptions in the brain during REM sleep. During REM (i.e., the dream phase of sleep), an area of the brainstem called the pons sends signals to the cerebral cortex, which is the area of the brain responsible for thinking and organizing information. The pons also sends signals to muscles in the body during REM, causing a type of temporary paralysis.

In a person with REM sleep behavior disorder, these signals translate into images that make up dreams. If the signals are interfered with, the person may physically act out dreams during sleep. For example, if a patient with REM sleep behavior disorder dreams about running, he or she might actually get up and run. As a result of this condition, patients may injure themselves or others. REM sleep behavior disorder is rare.

Restless leg syndrome (RLS) and periodic limb movement disorder (PLMD) are common sleep disorders, especially in the elderly. RLS is a genetic disorder resulting in prickly or tingling sensations in the leg that cause patients to want to move their legs. It often results in insomnia. PLMD causes jerking in the legs or arms that occurs frequently during resting or sleeping. Jerking may occur as many as 3 times in a minute and each jerk can wake the patient.

Excessive Sleep

Narcolepsy is a condition that causes patients to fall asleep uncontrollably throughout the day for periods lasting less than a minute to more than half an hour. These sleep attacks can occur at anytime, even while the person is engaged in an activity. During sleep, narcoleptics have an abnormal sleep pattern: They enter REM sleep prematurely without going through the normal sequence of sleep stages.

Narcolepsy usually is a genetic (inherited) disorder, although it may be associated with brain damage or neurological disease. The condition usually develops between the ages of 15 and 30. Some people with narcolepsy experience increased sleep attacks during pregnancy, illness, fever, or stressful periods. Patients with narcolepsy often feel tired most of the time. Other symptoms of the condition include cataplexy, sleep paralysis, and hypnagogic hallucinations.

Cataplexy is weakness or paralysis of the muscles. In narcoleptic patients, it may be triggered by tiredness and intense emotions and may be accompanied by short, sudden episodes of laughter or anger. When cataplexy occurs, persons who are standing may fall down.

Sleep paralysis is the inability to move the arms, legs, or entire body that occurs when a person is falling asleep or waking up. It usually lasts a very brief period of time. People who experience sleep paralysis may become very anxious and often regain movement only if they hear a loud noise or another stimulus.

Hypnagogic hallucinations or pre-sleep dreams, are dream-like hallucinations that occur in the transition between being awake and being asleep. Often, they are very vivid, frightening dreams.

Causes

Sleep disorders are very common and they can result from a number of causes. Stress, illness, diet (e.g., caffeine, alcohol), and medications (e.g., antidepressants) all can cause sleep difficulties.

Genetics
Narcolepsy is the only major sleep disorder with a known genetic basis (i.e., hereditary condition).

Night Shift Work
The body has an internal system of signals in the brain that controls normal physical and mental function during the course of a 24-hour day (called the biological clock). For example, the biological clock responds to external cues like sunshine and darkness and controls when a person sleeps (or feels sleepy). In most cases, the darkness of the night triggers sleepiness.

Night shift workers often experience sleep disorders, because they cannot sleep when they start to feel drowsy. Their biological clock is telling their body to do one thing while they are doing something entirely different. People who work at night often have an increased risk for heart and digestive problems, as well as emotional and mental problems.

Blindness

The inability to detect light and darkness may cause disruptions in the biological clock, which can result in sleep disorders.

Mental Illness
Most patients with mental illness experience some type of sleep disorder. Depression often causes patients to wake up early in the morning, unable to go back to sleep.

Physical Illness
Many physical illnesses and diseases cause sleep disorders. Difficulty sleeping can result from chemical changes in the body caused by disease or by the medications used to treat the disease.

Aging
About 50% of adults over the age of 65 have some type of sleep disorder. It is not clear whether this is a normal part of aging, or a result of medications.

Diagnosis

Medical History
As with other neurological disorders, an accurate medical history is an essential component of a sleep disorder diagnosis. People with sleep disorders should keep a daily diary of activities and sleep—both when they try to go to sleep and when they actually do sleep. Behavior during sleep (e.g., snoring), and alcohol, tobacco, and other drug use should be reported to the physician.

Polysomnography
A polysomnogram is a sleep study that involves using electroencephalography (EEG) to monitor the brain and muscle activity, heart rhythm, and breathing during sleep. Patients are usually tested in a sleep lab, or they are given portable equipment to take home. The EEG monitors the various stages of sleep, which is interpreted by the clinician. For example, the EEG shows the degree of muscle activity during the various NREM and REM sleep stages. This information may provide clues about the type and cause of the sleep disorder.

Other Tests
In people with suspected obstructive sleep apnea (OSA), overnight oximetry (measuring the oxygen saturation in the blood) may be performed to determine the oxygen level during the apnea episodes.

In people with suspected narcolepsy, there are various tests that can be performed. The multiple sleep latency test (MSLT), for example, measures the time it takes for REM sleep to occur in patients who fall asleep suddenly and repeatedly. In people with narcolepsy, REM occurs immediately.

Treatment

Treatment for sleep disorders depends on the cause.

Insomnia
If sleep studies do not indicate a pathological (related to disease) cause, improving "sleep hygiene" is the best way to treat insomnia. This means consuming less caffeine, avoiding exercise late in the evening, and engaging in a regular relaxation routine before bedtime. For some people, watching TV at night is actually too stimulating and may keep them from falling asleep.

In most cases, sedatives should only be used on a short-term basis; however, some people require long-term drug therapy. Antidepressants (e.g., trazadone [Desyrel®]) may be effective in these patients.

Sleep Apnea
For patients who are overweight, a weight loss program can be helpful in treating obstructive sleep apnea. Avoiding sleeping on the back also can help relieve the condition.

Devices also are available that a person can wear during sleep. A CPAP (continuous positive airway pressure) machine can be used to apply pressure to the upper airway, preventing obstruction and keeping the airway open. Patients wear a small mask connected to the machine that provides pressure while they are sleeping.

Patients with treatable conditions, such as enlarged tonsils or a large deviated septum, may benefit from surgery. Patients with sleep apnea should never take sleeping pills because they can prevent the person from waking up enough to start breathing again.


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Restless Leg Syndrome and Periodic Limb Movement Disorder
These disorders may be treated using medication.

Narcolepsy
There is no cure for narcolepsy, but symptoms can be managed with medication. Stimulants can keep a person awake during the day, and antidepressants can help the patient sleep better at night. Stimulants include methylphenidate (Ritalin®), dextroamphetamine (Dexadrine®), and Provigil®.

These drugs are addictive and can have serious side effects. It is important for people with narcolepsy to get a good night's sleep.

Sleep Hygiene - How to Get a Good Night's Sleep
The National Institute of Neurological Disorders and Stroke recommends the following tips for getting a good night's sleep and managing various sleep disorders.

* Set a schedule. Try to go to bed and wake up at the same time every day, even on the weekends.
* Exercise daily, but not at night before you go to sleep.
* Avoid caffeine, cigarettes, and alcohol, all of which deprive a person of sleep or particular stages of the sleep cycle.
* Try to come up with some sort of relaxing bedtime ritual that you do every night before you go to bed, whether it is taking a hot bath or reading a book.
* Try to wake up to the sun and expose yourself to the early sunshine, not necessarily by going outside, but by opening curtains or shades and letting the sun come into your home. The sun helps trigger and reset your biological clock, the part of your brain that tells you when you are sleepy and when it is time to wake up.
* Make sure that the room where you sleep is not too hot or too cold.

For additional information about sleep disorders, please go to sleepchannel.

Insomnia:The Natural Medicine Perspective

* Treating insomnia by identifying its cause
* Chinese medicine model of sleep
* How what you eat affects how you sleep
* Hypoglycemia
* Lack of exercise
* Restless leg syndrome
* Other obstacles to restful sleep
* Herbal therapies that improve sleep
o Botanical treatments
o Homeopathic combinations
o Nutrient supplements

Treating insomnia by identifying its cause

Sleep problems that are not due to disease or metabolic disorders can be relatively easy to treat by identifying and addressing the underlying cause. There are several factors to consider when trying to determine the cause of insomnia. First, it is helpful to know whether the insomnia is due to difficulty falling to sleep (sleep-onset insomnia) or difficulty staying asleep (sleep-maintenance insomnia).

Sleep laboratory research has shown that 50% of all insomnia is due to psychological distress, especially anxiety depression.

Other causes of sleep-onset insomnia are: caffeine, alcohol, food reactions, disruptive environment or change in environment, pain or inability to get comfortable, fear of falling asleep and, paradoxically, fear of insomnia.

Sleep-maintenance problems are often caused by alcohol, drugs, food reactions, sleep apnea, restless-leg syndrome (also called periodic limb movement/PLMD, or nocturnal myoclonus), hypoglycemia (low blood sugar), pain or discomfort.

Chinese medicine model of sleep

The 3000-year-old Chinese medical model has divided the 24-hour cycle of a day into 2-hour increments when the qi ("chi" or vital energy of the body) concentrates in various organ systems throughout the body. Observing the time when sleep is disrupted can be an important clue to understanding the cause. For example, waking every night regularly at 2 a.m. coincides with the time when the liver meridian is most active. This may indicate a problem with liver "heat" and detoxification stress. Asthma may wake you between 3 a.m. and 5 a.m. when the lung meridian is most active. A Chinese medical evaluation is also extremely useful for treating insomnia. Chinese medicine and acupuncture provide very effective tools for the treatment of insomnia by treating the underlying disturbances in qi circulation. Usually, restlful sleep can return after the first few treatments.

How what you eat affects how you sleep

There are several components in foods that can interfere with sleep. Chemical additives and naturally-occurring compounds are equally responsible. Different people may react differently to different foods. Sulfites, even small amounts found in olives for example, may cause one person to be up all night but have no effect on somebody else. By reviewing what has been eaten throughout the day, especially for the evening meal, a food culprit can usually be identified.

On the nights when you are having trouble sleeping, recall the foods of the day. Begin to pay attention to how you feel after eating. A problematic food will often create an unusual sensation in the body. Sometimes this manifests as a mild humming or buzzing feeling in the abdomen or limbs. Headache or irritability can also indicate food reactivity, as can feeling "wound up" in the evenings after dinner. See the section on food allergies: adaptation and withdraw in the natural medicine glossary for more guidance in these topics.

Hypoglycemia

Low blood sugar is a common cause of sleep-maintenance insomnia. A diet high in refined carbohydrates (breads, pasta and sugar) can lead to problems in blood sugar metabolism.

Lack of exercise

A lack of exercise can contribute to restlessness at night. Twenty to 40 minutes of aerobic exercise on a daily basis in the morning or late afternoon can substantially improve the quality of sleep at night as well as the sense of vitality while awake.

Restless legs syndrome (also known as periodic limb movement)

Refer to Restless Legs Syndrome & Periodic Limb Movement for a description of this disorder. When there is no family history of this disorder, additional testing is useful to rule out a low-grade iron deficiency or folic acid deficiency. Often there can be a sub-clinical deficiency in these nutrients and supplementing them can resolve the imbalance and help support a good night's sleep. Magnesium and vitamin E are also very helpful.

Other obstacles to restful sleep

Despite the popular lore about a nightcap before be for a restful night, alcohol is a major contributor to sleep deprivation. Drinking even one drink 2 or 3 hours before bed can create problems. Some people are more reactive to alcohol than others, and often the only way to determine if this is a factor is to abstain for several nights and note your sleep patterns.

Herbal therapies that improve sleep

When insomnia is due to nervousness, anxiety or depression, temporary measures can encourage sleep during a crisis so that the immune system does not get too run down. The following botanical treatments, homeopathic combinations and nutrient supplements can be supportive for short periods of time.

Botanical treatments

* Valarian (Valeriana officinalis): take 150 to 300 mg standardized extract of 0.8% valerenic acid 1 hour before retiring
* Passionflower (Passiflora incarnata): take 300 to 450 mg standardized extract of 2.6% flavinoids 1 hour before bed
* Skullcap (Scutellaria laterifolia): use 1 tsp dried herb to 1 cup hot water; drink in the evening to calm the nervous system.
* Kava (Piper methysticum): take 50mg standardized extract to reduce anxiety that may be inhibiting ability to fall asleep.

Homeopathic combinations

There are several over-the-counter formulas that can be very helpful toward getting a restful night's sleep, including:

* Calms Forte by Hyland Homeopathics: use as directed
* Calm Formula by Boericke
* Insomnia Formula by Hylands Homeopathics: take as directed

Nutrient supplements

These should be taken 1 hour before bed for the best results:

* 5-Hydroxytryptophan (5-HTP): take 100 - 300mg with fruit juice or other carbohydrate (e.g. crackers or soy milk); this amino acid precursor to serotonin can be supplemented to support serotonin production in the brain and improve sleep.
* Magnesium citrate: 250mg
* Flax seed oil: 1 Tbs daily; this essential fatty acid tonifies (strengthens) the nervous system
* Melatonin: take 3mg; a low serum melatonin level is often the cause of insomnia in elderly patients. This hormonal preparation should only be taken after blood melatonin levels have been determined, as there may be associated alterations in hormonal balance when melatonin is supplemented needlessly. It is only useful when levels are low. Jet lag is another time when melatonin supplementation may be appropriate to quickly re-calibrate the pineal gland's own production of melatonin and get body's the internal clock back on track.