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Sleep Basics

 

 

 

 


By Francis J. Janton, III, M.D.

 

 

 

 


Pennsylvania Neurological Associates

110 Lowther Street

Lemoyne, PA 17043

717-774-2202

www.pneuro.com

 

Dr. Janton treats patients in our practice with sleep disorders and interprets Polysomnograms, MSLT’s and EEG’s

 

 

NORMAL SLEEP

 

Roughly a full third of our lives is spent in sleep, so you’d think people would pay it much more attention. More important is the tremendous effect the quality & quantity of our sleep have on our waking lives. Disorders of sleep are implicated in productivity loss, substance abuse, and even traffic and air deaths.  Sleep affects the way we feel, our work and any activity where attention and vigilance are important.  When our sleep is good , we feel refreshed, rested & energetic. When its poor…we feel sleepy and productivity suffers. Our general and well being suffer with potential for chronic diseases. You have to ask why, for so many Americans, sleep is their last priority. 

 

Sleep requirements vary with the individual. Most people require about 8 hours, but 7 or 10 hours are what it takes for some to feel rested. The time it takes to fall asleep varies as well. This depends on our level of sleepiness, the environment, our psychological state, the time of day, and many other factors. Generally 20 minutes is average.

 

We should feel rested when we wake up.  If we are abruptly awakened from a deep sleep we can feel tired and groggy, but most mornings one should feel rested and refreshed.        

 

Sleep comes in different types or stages. The main categories are light sleep, deep sleep and dream sleep. Light sleep refers to stages 1 & 2. Generally we begin our night of sleep in light sleep, and the majority of time in sleep is spent in these stages. Deep sleep, also referred to as delta sleep or restorative sleep, encompasses stages 3 & 4. Dream sleep is referred to as REM…standing for rapid eye movements.

 

REM sleep has also been  called paradoxical sleep. This refers to the fact that our brains are extremely active while our muscles are for the most part paralyzed. This keeps us from acting out our dreams. Our heart and breathing rates are erratic. The EEG brainwaves resemble the waking state.

 

Adults have a normal sleep cycle of about 90 minutes. During that time we progress through the stages and include a period of REM. We will have several cycles during the night, with varying  percentages of the different stages. There is more deep sleep in the early  part of the night with the longest REM periods towards morning.

 

 

SLEEP DEBT  

 

Sleep debt refers to the concept that our bodies and minds require a definite amount of sleep . Many of us simply don’t get the required amount or quality and suffer the consequence --.sleepiness. This leads to decreased alertness, productivity and even safety. Accidents of many types have had inadequate sleep as a major contributing factor…industrial, automotive etc…to the point that this is a very significant public health issue.

 

Most of us need about eight hours of sleep per night. When we don’t get this amount the debt accumulates, usually until we sleep in and make it up. For some , with a sleep disorder, the quality of sleep is the issue and extra hours can’t help.  Sleep is increasingly being understood as a complex state with profound effects on our overall health.

 

SLEEP & AGING

 

There is a tremendous change in our sleep patterns, needs and quality throughout our lives. Although the restorative function remains the same, there is a marked evolution in the staging, patterns, quantity and even tendency  to timing of bedtime.

 

Neonates and infants spend the largest part of their lives in sleep. A large part is deep sleep and this is when growth hormone is secreted. REM sleep in the very young is also referred to as active sleep.

 

Unlike REM in the adult and older child, there is quite a bit of muscle activity during active sleep, representing a lack of maturation of the brainstem nuclei. Gradually as the brain matures the sleep patterns, staging and quality come to resemble the adult.

 

Preadolescents seem to be the model for ideal human sleep. Their sleep latency, or time to fall asleep is low. Their sleep is highly efficient, with few arousals and they generally awaken refreshed and are rarely sleepy during the day.

 

Problems arise during adolescence. Most of us are familiar with the tendency in this age group to want to stay up later at night. This reflects at least partly the biological change in the sleep clock or circadian rhythm. That is, there is a natural tendency  toward longer periods of sleep occurring later in the night. This is accompanied of course by a tendency to sleep later into the morning. When it is a problem this is called the delayed sleep phase syndrome. Unfortunately our society at this time requires teens to be up even earlier in the morning, when their body temperatures, hormonal levels and sleep clocks battle with them in the struggle to remain alert. There is definitely a need as well for more sleep in hours per day, and many education experts are calling for later school starting times for high and junior high school.

 

Most adults note a tendency to increased numbers of brief arousals each night. These may be for bathroom needs, or not and are generally very brief and not of significant consequence to the quality of sleep. As we age the amount of  fragmentation of sleep does increase. That is , there are generally more awakenings and arousals and less continuity of sleep. There is a gradual reduction in the amount of total sleep and deep sleep . Long periods of REM are less evident, but REM as a percentage of total sleep time remains fairly constant.

 

In the elderly there is a greater tendency (unclear and perhaps partly environmental reasons), to go to bed earlier, and wake up earlier in the morning. Sometimes this is a problem ,with the perception of abnormal early awakenings and is called the advanced sleep phase syndrome. Exposure to bright light in the evening can delay bedtime and allow sleep later into the morning.

 

 

 

 

 

 

 

SLEEP APNEA

 

OBSTRUCTIVE

 

By  far the most common disorder seen in sleep labs in the US is obstructive sleep apnea. Its estimated by some to be present in 10% of folks, with a tremendous  variation of incidence depending on age, sex and even body habitus.  Being overweight is a significant risk factor. This disorder of breathing during sleep is a major cause of excessive daytime sleepiness. The sleepiness and history of loud snoring are what typically brings patients to medical evaluation. Less commonly bed partners observe frank periods of apnea.

 

Apnea refers to a period of ten seconds or more of not breathing, generally corresponding to two missed breaths or more. During that time the upper airway has collapsed , obstructing the flow of air. A  partial obstruction is referred to as a hypopnea. There may be a simultaneous decrease in blood oxygen, an increase in heart rate and blood carbon dioxide level and an arousal. Breathing resumes ,often with a loud noisy breath and sleep continues but has been disrupted. This can happen many times an hour…in severe cases more than once a minute with apnea periods lasting ten to sixty seconds or more.

 

Sleep apnea presents tremendous health risks, which are increasingly being recognized. The most effective treatment for this disorder is nasal CPAP, continuous positive airway pressure. This is worn at night as a mask connected to a lightweight ,relatively quiet machine and eliminates the obstruction. Snoring is eliminated as are arousals. Normal breathing is restored and there are no longer oxygen desaturations. Daytime alertness is dramatically improved and health risks such as stroke, hypertension,  and heart disease are reduced. Spousal  quality of life is greatly improved as well, with no more worries about breathing problem and no more snoring!

 

Other treatments are available and their use depends to some extent on the severity of the disease, the presence or absence of specific anatomic or other problems such as a nasal obstruction, and whether or not CPAP is tolerated well. These include surgery, dental appliances, bed positioning and other ancillary measures. Weight loss is an important measure in most cases.

  

 

CENTRAL

 

Central apneas refer to a lack of effort to breath rather than an obstruction. This condition is also seen is folks with obstructive apnea, but is associated with a variety of neurological and cardiac diseases. It is much less common than central apnea and may respond to CPAP or medical therapy.  

 

 

NARCOLEPSY

 

Narcolepsy is a disorder characterized by severe daytime sleepiness. The hallmarks of the disease are sleep attacks and cataplexy.  Sleep attacks are irresistible episodes of  sleep of short duration, usually less than 1 hour. Sleep can easily be broken by external stimulation. These “naps” are generally refreshing.

 

Cataplexy refers to a sudden loss of muscle tone most often triggered by emotion. All or some of the muscles may be involve. Classically there is a fall as the knees unlock, the jaws sag, the head falls forward and the arms drop to the side. The attack may be partial or complete, and may last from seconds to 30 minutes. Stress, fatigue, heavy meals, and emotion are triggers, with laughter and anger  the most common precipitants. Cataplexy can occur while feeling elation at reading a book or watching a movie or may be without obvious precipitant.

 

Commonly the attacks of cataplexy may not be so dramatic and even unnoticed by others nearby.  Speech may be broken because of intermittent weakness and stuttering might occur. If the arms are involved then the person might complain of dropping things when surprised or laughing. Often these can be difficult to diagnose.

 

 

Sleep paralysis and hypnagogic hallucinations are sometimes associated with narcolepsy though they are not necessary for making the diagnosis and may be seen in people who do not have the disorder. Sleep paralysis  is the terrifying experience while falling  asleep or waking of being suddenly unable to move, speak, or even breathe deeply. Being unable to open eyes can even further contribute to the anxiety.                                        Hypnogogic hallucinations are often visual. This may involve colored shapes of constant or changing size, images of animals or people, in color or black and white. Auditory hallucinations may occur and can range from a collection of sounds to an elaborate melody. All of these episodes are typically about 20 minutes and always end spontaneously.

 

Usually symptoms begin around puberty, though there is a range of onset from 3 to 45 years old. The first symptoms are usually excessive daytime sleepiness and sleep attacks. Cataplexy usually begins at the same time, but may begin years after sleepiness complaints and rarely before. Hypnogogic hallucinations and sleep paralysis are often transitory and do not affect all patients.

 

Narcolepsy is not rare. A genetic link is evident. Diagnosis is made by a Multiple Sleep Latency Test following an all night comprehensive Polysomnogram . A short latency to sleep (patient falls asleep right away) and REM onset naps are characteristic.

 

Treatment remains directed at the symptoms. Considerable relief is often experienced by taking several short naps a day, and this is encouraged. Drug therapy typically uses stimulants such as dexedrine, methylphenidate, and recently modafinil. Tolerance to these drugs can be a problem. Other treatments such as tricyclic antidepressants are used for the other symptoms such as cataplexy.

 

 

RESTLESS LEGS SYNDROME

   

Complaints of an uncomfortable sensation of restlessness in the calf muscles are the primary  symptoms of restless legs syndrome (RLS).  A description of  “burning”, “tingling”, “pulling”, or “drawing” sensations are often heard. Although the calf muscles are usually involved the thighs or arms might be affected.  Movement  provides temporary relief but the distracting and unpleasant sensations return soon after movement ceases. The symptoms are worse when relaxing and lying down and are generally confined to the late evening hours. RLS is fairly common over age 50. The diagnosis is made by the history and a sleep study is not usually done. About 90% of patients with restless legs will have periodic limb movement disorder.

 

 

PERIODIC LIMB MOVEMENT DISORDER

 

This is a sleep disorder characterized by successive  slow writhing retractions of the foot and leg. The movements are brief lasting a second or two, occur at 15-40 second intervals during non-REM stages I and II sleep. Movements may involve one or both legs The condition is diagnosed by overnight polysomnography, where standard scoring rules have been developed with attention to the association with an EEG arousal. Five limb movements per hour associated with arousals are considered to be significant .

 

Both this disorder and RLS can be associated with iron deficiency anemia, kidney failure and peripheral neuropathy and some other medical conditions. Treatment of the medical condition may help the symptoms.

 

Other treatment includes drugs often used to treat Parkinson’s disease such as carbidopa/levodopa, and dopamine agonists such as bromocriptine. Many other drugs have been used to help as well including clonazepam, carbamazepine, propoxyphene and more. Treatment can result in dramatically improved sleep quality and consequent increase in daytime alertness. Bed partners are often relieved to  be free from being kicked!

 

IDIOPATHIC HYPERSOMNOLENCE

 

This can be considered a diagnosis of exclusion, that is...all other diagnostic possibilities have been eliminated.  The symptoms can be very much like narcolepsy . The MSLT however shows no REM onset naps . Treatment is very similar  to narcolepsy.

 

 

INSOMNIA

 

Poor sleep is one of the most common complaints in medicine let alone a sleep practice. We’ve all experienced situational  insomnia, the inability to fall asleep or stay asleep occasionally. These bad nights are usually the reflection of excitement , tension or worry. However some insomniacs may be totally relaxed and still sleep poorly due to some weakness in their sleep system.

 

Insomnia sometimes occurs due to maintenance of certain factors affecting  sleep learned during a now resolved emotional event. Others develop increasing difficulty sleeping as they grow older or in association with a medical illness. Sometimes substance abuse , psychological disorders and sleep disorders can be present in varying degrees or in combination.

 

Transient or short term insomnia ,event related, can often be helped with healthy sleep habits or sleep hygiene, but sometimes a medication is needed for the short term.

 

Chronic insomnia is a much more difficult problem. Often it is due to a combination of factors which can include inherently light sleep, age associated sleep fragmentation or a tendency to anxiety and depression. Often a true emotional conflict such as a death or other loss can be a trigger. Dealing with this stressful situation can induce a transient insomnia. Over the next few weeks a conditioned response can develop with expectations of poor sleep and associating the bed with the anxiety of not being able to sleep. Poor sleep hygiene often follows. This condition can be maintained even after the loss or situation has resolved.

 

Resolution of chronic insomnia requires a combined approach of treating any medical or psychological  problems that may exist, assessing the possible effects of medications and substances, and especially a review of sleep hygiene and behavioral treatments.

 

Many medical conditions can contribute to insomnia. Pain disorders are especially noteworthy, including fibromyalgia and others. Psychological and psychiatric disease including especially depression and anxiety disorders very  often include quite prominent sleep disturbance. This paper does not specifically deal with the treatment of any of these disorders and many resources are available  for specific conditions. Suffice it to say that optimal treatment of these conditions is a first step towards treating the associated insomnia. Following that certain measures directed towards healthy sleep can be helpful.

 

 

Sleep Hygiene:

 

Sleep hygiene refers to healthy lifestyle patterns that are conducive to optimal sleep. One thing to remember is that these sleep patterns are particularly individualistic. That is, what is good for one person may not be for another. An example might be naps. Most always it is recommended to avoid naps and to get all the sleep during the night, but for some folks, a short daytime nap may be better. The person may no longer be so desperately seeking sleep and be more relaxed about going to bed at night. In evaluating sleep habits, a daily sleep log ideally for two weeks is kept. A basic recommendation is to respect the  circadian rhythm.  For most people, this is close to 24 hours, although, for young persons, that may be longer than 24 hours, and in the elderly, it may be shorter than a 24-hour clock. Maintaining this circadian rhythm is helped by being exposed to bright light during the day at certain points, even after a night of poor sleep.

 

It seems that the more one tries to sleep, the less easy it is achieved. Quiet activities, reading and listening to music do promote relaxation and sleep. TV watching for some might be relaxing, but for most people, the medium is actually rather stimulating with the combination of varying visual imagery and auditory signals. Commercial TV, in particular, is quite activating and most sleep specialists recommend removing the TV from the bedroom, and not watching TV immediately prior to going to sleep.

 

Exercise should be done in the earlier part of the day and no later than early evening to promote sleep. This effect evolves slowly over weeks, whereas, intermittent exercise doesn't have as much effect. Exercise late in the evening is detrimental to falling asleep. Relaxing in a hot tub of water before bed may have a beneficial effect. The bedroom environment should be optimal in terms of temperature and avoiding noise. When noises are unavoidable, a background noise such as a radio tuned between stations is helpful. Removing the clock from sight while sleeping is important.

 

One rule that has been recommended is to get up from the bed after 20 minutes of sleeplessness and go to another room to do a quiet activity, not TV.  When sleepiness is felt, one should return to the room. This cycle could be repeated several times and is much preferred to tossing and turning for a prolonged period of time. Eventually sleep will happen. Also, using this and other practices, the bed will become more associated with sleep itself rather than the anxiety associated with the inability to sleep.

 

Poor sleep habits are rarely the cause for insomnia, but often can perpetuate it.

 

Drugs need to be looked at closely. Tobacco and coffee are often not metabolized for eight hours and should be avoided in that time frame. Tobacco especially should be avoided near bedtime. Alcohol, while it can promote the onset of sleep, disturbs the sleep architecture and fragments sleep, as the alcohol is metabolized. Several studies have shown a clear correlation between alcoholism and insomnia, and alcohol is not recommended as a hypnotic agent. Short term use of short acting hypnotic agents are appropriate in certain situations.

 

One very destructive sleep pattern is shift work.  It’s hard enough to get used to a job where you work overnight. On your days off, you’ll often have to sleep when everyone else does, in the middle of the night. But with shift work you have to make the adjustment, depending on your work schedule to alternate day and night sleep patterns.  Some young people may be able to adjust for awhile.  But eventually sleep patterns begin to suffer. Your body doesn’t know whether to be awake or asleep when it has to function according to someone else’s requirements. In addition the brain works in approximately 24 hour cycles, or circadian rhythms described above, and all of that is altered by artificial schedules.  Far better to work regular hours. Even astronauts who work in space where there is no day or night, try to keep to a regular sleep schedule. If work has to be done overnight, that’s better than alternating hours in shifts. For employers, productivity will likely suffer. Employees may be sicker working shifts. Accidents may happen.

 

 

PARASOMNIAS

 

Parasomnias are phenomena that are exaggerated by sleep and are, in general, quite disruptive. These can occur in various stages of sleep and affect people in different periods of their lives.

 

Sleep walking or somnambulism occurs in slow wave sleep or non-REM sleep. The episodes usually involves complex behaviors that can range from merely sitting up in bed to walking. They involve such automatic behavior as dressing, eating, going to the bathroom or even driving a car. Coordination,  however, is quite poor and speech is usually not intelligible. Sleep walkers may avoid objects in their path, but are usually much clumsier then they would be if they were awake. Sleep walking is more evident under periods of sleep deprivation or with alcohol and must be differentiated from epilepsy. For the most part, the main concern for patients with sleep walking is safety. The patients should sleep on the ground floor and have potentially dangerous objects removed from the room. In some cases double locks are needed.

 

Night terrors, another non-REM parasomnia, are more commonly associated with children between the ages of two and ten. They are very dramatic episodes with piercing screams or cries accompanied by obvious tearful manifestations. The child is usually unable to be calmed for several minutes, but the episode is typically not remembered. The episodes can be more evident in times of stress and it is important to have normal sleep schedules and avoid discussion of the episodes. This typically disappears in adolescence.

 

There is a variety of parasomnias that occur during REM sleep. The most common would be nightmares, sometimes called dream anxiety attacks. The dream is vividly recalled. These are typically normal occurrences in most adults from time to time, but if it occurs frequently, it can be a cause of chronic daytime sleepiness or anxiety, and further evaluation is indicated. These nightmares and sleep terrors must be distinguished from hypnagogic hallucinations that were discussed in the section in narcolepsy. This is an intrusion of REM sleep into wakefulness and typically occurs in conjunction with the other manifestations of those disorders. For the most part, nightmares are benign and self- limited, and not of significant cause for concern. Sleep terrors can be distinguished from nightmares as the latter are remembered in stark detail.

 

Sleep paralysis occurs during REM and, again, is most common in narcolepsy, but can occur in isolation in otherwise normal people. It can be a frightening experience of being unable to move the arms or legs usually at sleep onset. It can be seen in healthy people who are sleep deprived.

 

An increasingly recognized condition is REM sleep behavior disorder. The paralysis that usually accompanies REM sleep is broken down and the sleeper acts out parts of his dreams. The person acts out vigorous often dangerous behaviors that accompany very striking dreams. This can be quite violent and bothersome and can include attacks on bed partners and cause injury to the sleeper.

 

This motor behavior or dream enacting behavior can occur early in the night during the first REM period or as late as just prior to awakening. Patients usually present with a complaint of being injured during sleep rather than any other sleep disturbance. The dreams are vividly recalled and the sleep behavior usually fits in with the pattern of the dream. An evaluation should include a review of medications, discussion with the bed partner, and neurologic evaluation. Sleep studies are done sometimes if the history is not crystal clear and further work-up might be done to rule out seizure activity. REM behavior disorder does respond very well to medications and usually Clonazepam is prescribed with an excellent result.

 

TESTING

 

POLYSOMNOGRAPHY

 

A comprehensive polysomnographic evaluation is often done in the evaluation for sleep disorders. This is done in the setting of a sleep lab which may be in a hospital or in a free standing center. The evaluation is standardized and requires an overnight stay. The patient usually arrives early in the evening and meets the sleep technician. After a description of the study procedure, the patient has electrodes temporarily and painlessly placed. These include electrodes to record brain wave activity, eye movements and chin muscle activity. This combination allows evaluation of the sleep stage.

 

Further evaluation includes monitoring of respiratory efforts usually with abdominal and chest belts as well as air flow from the nose and mouth. Oxygen saturation is usually measured using a finger pulse oximetry and heart rate is monitored with EKG leads. Typically, muscle leads are placed on the legs to evaluate for possible periodic leg movements. In most centers, a remote camera is used so the study can be observed closely by the sleep technician. Despite all this, most folks do sleep in the lab!

 

The study may be repeated on a subsequent night if treatment is required with CPAP. This allows titration of the CPAP to the optimal pressure setting to eliminate apneas. On some rare occasions, a split night study is done where the first half of the study is done in a diagnostic mode and the second half of the night is done in the treatment mode with the CPAP. This is done with cases of extreme severity and is usually avoided if possible as the optimal study is done in two nights.

 

 

MULTIPLE SLEEP LATENCY TEST

 

Multiple sleep latency test (MSLT) is a nap study that is accepted as an objective measure of the degree of daytime sleepiness and is most helpful in diagnosing narcolepsy and idiopathic hypersomnolence. The MSLT has become standardized and widely used in both research and clinical application. The naps are a series of five naps separated by two hours each. The patient is given a 20 minute opportunity to fall asleep and the time to sleep onset is recorded as well as the possible presence of REM sleep. An MSLT is always performed after a prior polysomnography test. Sometimes drug screening is done in association with this evaluation.

 

 

 

 

 

 

 

By Francis J. Janton, III, M.D.

 

Pennsylvania Neurological Associates

110 Lowther Street

Lemoyne, PA 17043

717-774-2202

www.pneuro.com