Sleep Disorders

SLEEP DISORDERS

INTRODUCTION

Sleep disorders are one of the most common medical problems. Millions of Americans suffer from a sleep disorder, and the inability to sleep well has significant physical and psychological consequences.

When most people think of sleep disorders the word insomnia comes to mind. But insomnia is both a general term that refers to difficulty in the sleep process and it is the term used for a specific type of sleeping disorder. According to The International Classification of Sleep Disorders there are 11 different types of insomnia and there are multiple causes for each type of insomnia. For example, insomnia can be caused by medical conditions such as obstructive sleep apnea or restless legs syndrome, or it can be an acute or chronic problem called adjustment insomnia.

Although insomnia is generally used to refer to having difficulty sleeping, the precise definition of insomnia is more complicated than that. Insomnia is defined as: 1) difficulty in falling asleep; 2) difficulty staying asleep, and; 3) sleep that is not refreshing or restful.

Difficulty sleeping can be caused by a secondary medical condition, a psychological disorder such as anxiety or depression, or by a primary sleep disorder. When someone is complaining of the quality of her/his sleep, a sleep assessment will be done and all of these possibilities will be investigated. This module will discuss primary sleep disorders - sleep disorders that do not have a secondary medical cause or a psychological cause.Given the number and complexity of sleep disorders it would not be possible to discuss them all in any helpful manner, so this module will focus on three of the most common: 1) obstructive sleep apnea; 2) restless legs syndrome, and; 3) narcolepsy. The module will also discus the topics of sleep disorders in the elderly and sleep hygiene.

OBJECTIVES

After completing this module the learner will be able to:

1. Identify the correct definition of insomnia.

2. Identify the three most common sleep disorders.

3. Identify one commonly used treatment for each of the three sleep disorders.

4. Identify a population that is likely to suffer sleep disorders.

5. Identify the three basic principles of sleep hygiene.

THE DEFINTION OF INSOMNIA

The definition of insomnia provided in the introduction is essentially correct. However, not everyone who has difficulty falling asleep and difficulty staying asleep would be diagnosed as having insomnia. There are specific criteria that are used to make the diagnosis of insomnia, and the complete definition of insomnia is:

1. Repeated difficulty is falling asleep: Difficulty falling asleep is defined as taking

more than 30 minutes to fall asleep. The problem is considered to be acute if it

happens for 30 days or less, and it is considered chronic if it persists for longer

than 30 days

2. Repeated difficulty with staying asleep: Someone is said to have repeated difficulty

is staying asleep if: a) she/he sleeps for less than six hours, and/or; a) he/she wakes

up three or more times a night. . The problem is considered to be acute if it

happens for 30 days or less, and it is considered chronic if it persists for longer

than 30 days

3. Poor sleep quality: This is the final part of the complete definition of insomnia.

Poor sleep quality is described as sleep that does not leave someone feeling rested

and refreshed. These people will sleep but when they wake up, they do not feel

rejuvenated - they feel tired. . The problem is considered to be acute if it

happens for 30 days or less, and it is considered chronic if it persists for longer

than 30 days

Learning Break: The term insomnia can be a bit confusing. Insomnia refers to a specific condition that is caused by sleep disorders. But insomnia is also the name of a specific type of sleep disorder, as well.

SLEEP DISORDERS: THE SCOPE OF THE PROBLEM

The number of people who are affected by a sleep disorder varies and depends

on the specific disorder but taken as a whole, sleep disorders are very common. About one third of all US adults have a sleep disorder at some time in their lives and approximately 20% say that they have chronic insomnia. Insomnia is more common in women,adults, people who do shift work, and people who have certain medical or psychiatric problems.

Sleep disorders are also especially common in the elderly, and more than 50% of the elderly report some type of chronic sleep problem. Most elderly people who have problems with sleeping do not have particular difficulty falling asleep. But they do have difficulty staying asleep, and this has been well documented by sleep studies: the elderly on average have much more frequent, and much longer periods of interruption of their sleep than do younger people. Part of the problem can be explained by the increased incidence of medical conditions that can disturb sleep. Elderly people are also more likely to take medications that can disrupt sleeping patterns.

The implications of insomnia and sleep disorders in the elderly are serious. People who are elderly and do not have good quality of sleep are more likely to suffer falls, have an increased incidence of morbidity and morality, and suffer from daytime sleepiness.

WHAT IS SLEEP?

Sleep is one of the most essential human activities. But although everyone - and everything - sleeps and sleep has been studied for many years, it is still not entirely clear what sleep is, why we need it, or what happens to us when we sleep.

Most of us think of sleep as a simple, basic and passive process: close your eyes, nod off, and then wake up seven or eight hours later. And the need for sleep is very obvious. If you don’t get enough you become tired,so everyone associates sleep with rest. However when sleep is closely examined it is clear that sleep is not simple, it is not passive and although we sleep when we are tired, sleep in many ways is not a completely inactive and restful activity.

The Process of Sleep

Sleep happens regularly and naturally every night. During sleep we are essentially unconscious. We cannot respond to external stimuli unless it is very intense, the senses of sight, hearing, touch, etc. are either not operating or greatly diminished, and there is almost no voluntary muscle activity. When you see someone who is sleeping and from your own personal experiences of sleep, it would be easy to conclude that sleep is a time where the body and brain are basically inactive and that sleep is very simple.

But sleep is actually a complex activity and the body and the brain are definitely working during sleep. Sleep is not simple. It is actually a very complicated process that is comprised of five distinct phases or stages. We move through these stages as we sleep, we experience some of the stages more than once, and each one is characterized by brain wave activity and physical activity that are particular to that stage. The heart rate, breathing, and body temperature all fluctuate in specific ways during the stages of sleep, and the activity of the immune system, the activity and secretion of hormones, and the activity of all of the other organ systems do, as well.

One of the most important stages of sleep is called REM sleep. REM sleep is a good example of how complicated sleep is and how sleep is not actually passive or restful in the way we think it is. REM sleep is an acronym for rapid eye movement sleep. During REM sleep the eyes are moving rapidly and randomly. Most people have between four and five periods of REM sleep during the night. REM sleep is some times referred to as paradoxical sleep because although we are resting during REM sleep, the body and the brain are very active in ways that at times are quite different. During REM sleep:

• The heart is beating slowly and steadily, but the breathing is rapid and irregular.
• REM sleep is very deep sleep, but someone in the REM stage of sleep can be awakened very easily.
• The nervous system and the brain are very active during REM sleep but the musclesare barely moving.
• Brain wave activity during REM sleep is similar to brain wave activity during periods of full consciousness.
• REM sleep is the time in which we dream. We typically think of sleep as a very passive time but dreaming, an experience that everyone has, clearly shows sleep is anything but passive.

REM sleep then clearly shows that during sleep our consciousness is greatly decreased, our ability to react to external stimuli is much diminished, and voluntary muscular activity is essentially absent but there is a lot of activity going on. REM sleep is a time of intense activity of certain parts of the body and the brain, but sleep in general is very far from being a time in which our bodies are completely at rest. It has been estimated that the basic metabolic rate only decreases 5-10% during sleep. All of the body’s organ systems are working during the night: the immune system, the nervous system, the muscular system, and the skeletal system, for example, all use the period of sleep to rebuild and recuperate and these are active processes. During REM sleep, our brains use more oxygen than when we are awake. And when people are observed sleeping, we see that there is actually quite a bit of moving - tossing and turning - during the period of sleep.

Sleep then is a very active and complex process. However, although sleep has been extensively studied, it is still in many ways a mystery. We know quite a bit about what happens during sleep, and it is clear from sleep deprivation studies that sleep is vital for survival and optimal functioning. But we do not know the exact purposes of sleep. It may be that sleep is necessary for the conservation of energy, and sleep may be a time during which the body rebuilds and restores itself. If someone is deprived of sleep, wound healing and the function of the immune system are adversely affected. There is quite a bit of evidence that suggests that sleep is important because it gives the brain a “quiet time” during which it can organize knowledge and memories without the distraction of consciousness.

Why Do We Need to Sleep?

Despite the misconceptions about sleep and the fact that the exact nature and purpose of sleep are still not known, there is one indisputable fact about sleep: we have to have it.

If animals are not allowed to sleep they will die in several weeks, even if they have food, shelter, and water. Humans also suffer greatly if they do not get enough sleep or enough quality sleep. In particular if the REM stage of sleep is disrupted the consequences can be very bad. If someone is deprived of sleep or deprived of quality sleep, she/he will develop mood changes, irritability, and inability to concentrate and focus. The motivation to work and perform self-care activities will disappear. And if the lack of sleep or quality sleep is too intense or too prolonged, people will begin to hallucinate and they will develop an almost psychotic-like state of mind.

How Much Sleep Do We Need?

How much sleep do we need? What is a normal amount of sleep? These questions are often asked, and the answers are relatively simple. The amount of sleep that is normal and the amount that someone needs will depend on who that person is. Newborn babies sleep prodigious amounts. It is not unusual for an infant to sleep 16 to 20 hours a day. As we get older the need for sleep diminishes, and older adults and the elderly may only require six hours of sleep a night. The amount of sleep someone needs is also partly influenced by genetics. But the amount of sleep that is considered “normal” and the amount that someone needs can be easily assessed using one question: do you feel rested and refreshed after a night of sleep? If the answer is yes, that person is getting enough sleep and the idea of “normal” is not important. If the answer is no, then he/she needs more sleep.

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NARCOLEPSY

Narcolepsy is a sleep disorder that is characterized by these four signs.

1. Excessive daytime sleepiness. In order for someone to be diagnosed with narcolepsy, the daytime sleepiness must happen suddenly, without warning, and during normal daytime activities such as driving, talking, and working.

1. Cataplexy: Cataplexy is defined as a sudden onset of muscle weakness and decreased muscle tone. Cataplexy associated with narcolepsy may be generalized and severe, or mild and localized. An attack of cataplexy may only involve a few small muscles and last a few seconds, but in rare cases someone with narcolepsy who is having an attack of cataplexy will be unable to move for 20-30 minutes.

1. Hypnagogic and hypnopompic hallucinations: Hypnagogic hallucinations are hallucinations that happen immediately before someone who has narcolepsy falls asleep. Hypnopompic hallucinations are that happen when someone with narcolepsy wakes up.

1. Sleep paralysis: Sleep paralysis is a temporary paralysis that occurs at the beginning of sleep or when waking up. In most cases of narcolepsy accompanied by sleep paralysis, the person is unable to move when he/she first wakes up; sleep paralysis that occurs when falling asleep is less common. Someone who has narcolepsy and sleep paralysis literally cannot move when these episodes occur, but she/he is fully conscious. Physical contact will often be enough to end the episode of sleep paralysis.

Excessive daytime sleepiness is seen in everyone who has narcolepsy. The other three signs occur very frequently, but not everyone who has narcolepsy will have all four.

Although narcolepsy is one of the most common sleep disorders, it is a relatively rare problem. Narcolepsy affects less than one percent of the population: the incidence of this disorder is estimated to be 0.02-0.18% of the US population. Men are more likely to develop narcolepsy than women by a ratio of 1.64:1. Narcolepsy usually begins during the second of life, but children as young as two years old have been diagnosed with narcolepsy.

What Causes Narcolepsy?

Narcolepsy is a complex disorder, and there is no single cause of the disease. However, researchers believe that there are three pathologic mechanisms that combine and interact to produce the signs and symptoms of narcolepsy.

There is evidence that suggest that genetics determine who develops narcolepsy. However, the influence of inheritance is not well understood and it is not always a strong predictor of who will get narcolepsy. For example, first-degree relatives (i.e., a parent, sibling, or offspring) of someone who has narcolepsy are 10-40 times more likely to have narcolepsy than someone without the disease. However, in situations in which you might expect narcolepsy to occur - in identical twins for example - it is actually less common than among first-degree relatives. It may be that narcolepsy is like many diseases: some people have a genetic abnormality that makes them likely to develop narcolepsy, but they will only develop the disease if they are exposed to certain environmental conditions or if they have other risk factors.

It may also be that narcolepsy is caused by an inadequate amount of a certain brain neurotransmitterand a lack of the brain cells that produce this neurotransmitter. Many people who have narcolepsy have been found to be totally lacking a brain neurotransmitter called hypocretin, and they have few to none of the brain cells that produce hypocretin. Hypocretin is a neurotransmitter that controls wakefulness and sleep. If there is little or no hypocretin in the brain, then the very complex cycle of wakefulness and sleep is disrupted, and sleep will happen unpredictably, uncontrollably, and at abnormal times.

Lastly, researchers also believe narcolepsy is caused, in part, by an autoimmune process. The immune system of the body is a complicated system of organs and specialized tissues and cells that identify, attack, and neutralize bacteria, toxins, and viruses that are foreign and potentially harmful. An autoimmune disease can be considered to be “a case of mistaken identity.” Instead of isolating and killing harmful foreign bacteria and viruses, the immune system attacks normal healthy tissues. There is evidence - not conclusive evidence, but very suggestive evidence - that the immune systems of people who have narcolepsy are destroying the cells that produce hypocretin.

What Is It Like To Have Narcolepsy?

The four signs of narcolepsy, excessive day time sleepiness, cataplexy, hypnagogic and hypnopompic hallucinations, and sleep paralysis, were described earlier. These describe how narcolepsy is diagnosed. Anyone reading the description of those four signs can imagine that narcolepsy can be anextremely difficult illness to live with. However, these physical signs of narcolepsy don’t tell the whole story of the profound effects narcolepsy can have on someone’s emotions, social life, and professional life. Narcolepsy is also associated with many serious physical and psychological illnesses. People who have narcolepsy face some of the following problems: