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Sleep Disorders

Sleep apnea
Restless leg syndrome
Periodic limb movement disorder (PLMD)
Circadian rhythm sleep disorders

Sleep apnea

Sleep apnea is defined as the cessation of breathing during sleep and can be a serious, potentially life-threatening condition. There are two types of sleep apnea: obstructive and central. Of the two, obstructive sleep apnea is the most common.

Obstructive sleep apnea

What is obstructive sleep apnea?

Obstructive sleep apnea (OSA) is characterized by repetitive breathing pauses during sleep due to an obstruction of the upper airway. Respiratory effort continues during these episodes of "apnea." These breathing pauses are almost always accompanied by snoring between apnea episodes, although not everyone who snores has this condition.

What causes obstructive sleep apnea?

Obstructive sleep apnea is caused by a blockage of the airflow when the soft tissue in the back of the throat collapses during sleep.

During the day, your muscles in this region keep the air passage open. However, as a person with OSA falls asleep, these muscles relax and the airway may collapse. This blockage can be complete or partial but both can lead to the same consequence of repetitive disruption of sleep and decline in oxygen levels.

What happens during an obstructive sleep apnea event?

When the airway becomes obstructed, air exchange temporarily stops while the respiratory effort continues. During this apnea event, physiologic changes occur that cause the sleeper's brain to briefly awaken to open the airway and resume breathing. This arousal from sleep usually lasts only a few seconds, short enough for the sleeper to be unaware of the interruption to sleep, but long enough for normal breathing to be restored. Once normal breathing is restored, the person falls back to sleep, only to repeat this cycle again. A consequence of these brief arousals is sleep fragmentation and poor quality of sleep.

What are the signs and symptoms of untreated obstructive sleep apnea?

  • Snoring
  • Observed episodes of not breathing
  • Choking sensation when trying to sleep
  • Excessive daytime sleepiness
  • Difficulty concentrating
  • Irritability/depression

What are the consequences of untreated obstructive sleep apnea?

  • Increased risk for high blood pressure
  • Increased risk for a heart attack or stroke
  • Increased risk for motor vehicle accidents

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What is narcolepsy?

Narcolepsy is a neurological sleep disorder defined by periods of excessive sleepiness and an uncontrollable need to sleep. Persons with this disorder may suffer from bouts of irresistible sleepiness or "sleep attacks" that may be temporarily relieved by short naps. Narcolepsy is a chronic disorder that generally begins in the teens or early twenties but can also be identified later in life.

What causes narcolepsy?

Recent evidence suggests that narcolepsy may be related to a dysfunction of a neurotransmitter system (Orexin or hypocretin) in the area of the brain called the hypothalamus. The hypothalamus is one of the areas of the brain that regulates the sleep-wake cycle.

What are the symptoms of narcolepsy?

The development, number and severity of symptoms vary widely among individuals with this sleep disorder. Early diagnosis and treatment, however, can be important in improving physical and mental well being of the individual affected.

Primary symptoms

  • Excessive daytime sleepiness
  • Cataplexy: A sudden, brief episode of muscle weakness brought on by changes in emotion such as laughter, surprise, and anger
  • Sleep Paralysis: An inability to move while going to sleep or upon awakening from sleep
  • Hypnogogic Hallucinations: Vivid dreamlike experiences that occur just before falling asleep or upon waking up

Secondary symptoms

  • Disturbed nighttime sleep involving multiple arousals or frequent awakenings
  • Automatic behavior: The performance of a brief or simple routine task, without conscious awareness of doing it, and often without later memory of it

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Restless leg syndrome

What is restless leg syndrome?

Restless leg syndrome is a disorder characterized by discomfort in the legs or rarely, in the arms while sitting or lying down, usually in the evening or just before falling asleep.

What causes restless leg syndrome?

The exact cause of restless leg syndrome is unknown but the disorder is associated with a number of medical and neurological disorders such as:

  • Damage to peripheral nerves from diabetes and other causes
  • Certain nutritional deficiencies, especially iron
  • Medical illnesses like kidney failure or arthritis
  • Certain substances like excessive caffeine or anti-depressant medications may contribute to this condition as well.

What are the symptoms of restless leg syndrome?

A person with restless leg syndrome experiences sensations that usually occur in the legs, but sometimes can present in the arms as well. The sensations are described as:

  • Irresistible urges to move the arms or legs while awake
  • "Creepy-Crawly" sensations within the extremities
  • Sleep difficulty or insomnia

These symptoms usually develop in the early evening or at the beginning of the night and are worse at rest. Temporary relief of symptoms usually occurs when the affected person moves around or stretches the limbs.

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Periodic limb movement disorder (PLMD)

What is periodic limb movement disorder?

Periodic limb movement disorder is characterized by periodic episodes of involuntary limb movements that occur during sleep. The rhythmic episodes usually occur in the legs and consist of a forward or backward extension of the big toe in combination with partial flexing of the ankle, knee, and sometimes the hip. Similar movements can occur in the arms as well. The affected individual is usually unaware of the repetitive motion or the accompanying brief awakenings that disrupt their sleep.

What causes periodic limb movement disorder?

PLMD is often associated with or evoked by a variety of medical conditions. This disorder becomes more common as people age and many people who have Restless Leg Syndrome also have PLMD.

What are the symptoms of periodic limb movement disorder?

  • Excessive daytime sleepiness
  • Insomnia
  • Bed partner unable to sleep
  • Restlessness

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What is parasomnia?

"Parasomnia" refers to a wide variety of behaviors or conditions that intrude into our sleep, and often the sleep of those around us, in a very active and sometimes dramatic way. These behaviors are most often infrequent and mild, but they can happen often enough or become so bothersome that medical attention is required.

Younger children are more likely than adults to experience certain types of parasomnias and, in children, they usually do not indicate significant psychiatric or psychological problems.

What are some types of parasomnias?

There are a number of different classifications and types of parasomnias. The two classifications listed here, parasomnias associated with arousal and parasomnias associated with REM sleep, are most commonly encountered.

Parasomnias associated with arousal

There are three types of parasomnias that are associated with arousals: confusional arousals, sleepwalking, and sleep terrors. These types of parasomnias are grouped together because the arousal from sleep has been impaired. The onset of these events in slow-wave deep sleep is a typical feature.

What are confusional arousals?

Following arousal from deep sleep, the individual may appear awake, confused and upset, yet resists attempts by others to comfort or console. The episodes may last from several minutes to hours and usually end with the person calming, waking briefly, and then only wanting to return to sleep. It is common for the individual to have no memory of the event.

What is sleepwalking?

Sleepwalking or somnambulism is most commonly seen during the first third of the night and begins in slow-wave sleep. It is often seen in younger children, peaking during the ages of 4 to 8 years of age. It can be seen in adults as well, although this is uncommon.

Some sleepwalkers may simply walk around a room, while others will walk around the whole house or even go outside and then return to bed or awaken in a different part of the house. Also, sleepwalkers can carry on conversations, which are difficult to understand and make little or no sense. In severe cases where sleepwalking leads to physical injury, involves violence, excessive eating, or disturbs the bed-partner or family, consultation with a physician may be necessary.

What are sleep terrors?

Sleep terrors or night terrors, as they are commonly called, are abrupt awakenings out of deep sleep, often in the first third of the night, with profound fear. The person experiencing a sleep terror will usually bolt upright from their bed, yell, scream, cry, or even run. As disturbing and frightening as these events are to the observer, the person who is having the sleep terror event is usually totally unaware of what they are doing and has no recollection of the incident in the morning. During one of these events, the sleeper can physically injure him/herself or others as well. Sleep terrors are seen mostly in children ages 4 to 12 years of age, are more common in males, and tend to resolve by adolescence. However, sleep terrors can persist through to adulthood.

What can contribute to parasomnias associated with arousal?
  • Sleep deprivation: Insufficient sleep or irregular sleeping patterns are common reasons that a child has sleep terrors or walks in his sleep. This is because confusional arousals, sleepwalking, and sleep terrors occur during deep sleep. Following sleep deprivation, the body demands more deep sleep. The more deep sleep that a person gets, the more likely that he/she is going to have an episode.
  • Medication: Some medications may cause or worsen a parasomnia event.
  • Stress: Parasomnias often occur during periods of stress. It may be the stress itself that causes the sleep problems or the sleep deprivation that often goes along the stress
  • Fever or illness: A high fever or illness has been found to precipitate these types of parasomnias.

Other sleep disorders

Parasomnias can occur or be worsened by another underlying sleep disorder. For example, sleep apnea, which can cause someone to wake more frequently and create more sleep transitions and arousals can trigger a parasomnia event.

Parasomnias associated with REM sleep

These parasomnias are typically associated with the stage of sleep called rapid eye movement or REM sleep. A common parasomnia encountered under this classification is REM-sleep behavior disorder.

What is REM-sleep behavior disorder (RBD)?

REM sleep is an active phase of the sleep cycle for our brains, although most muscles are paralyzed during this phase of sleep. In some people, particularly in older men, this paralysis is incomplete or absent allowing the dreams to be "acted out." Such dream-related behavior can be violent and can result in injury to the individual or bed-partner. In contrast to those who experience sleep terrors, the person will often recall the content of these vivid dreams and they usually occur in last third of the night when the amount of REM sleep increases.

What can contribute to RBD?

The exact cause of Parasomnias is unknown, but there are factors that can trigger an event or make this sleep disorder more severe.

  • Various neurological disorders, especially Parkinson's disease
  • Aging

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Circadian rhythm sleep disorders

What is a circadian rhythm?

Circadian rhythm is an intrinsic clock that regulates our wake and sleep schedule and is located within an area of the brain called the suprachiasmatic nucleus (SCN). This "biological clock" is self-sustaining and regulated by light.

What are circadian rhythm sleep disorders?

Circadian rhythm sleep disorders occur when there are changes to an individual's intrinsic clock that affects their sleep time. The most common type of circadian rhythm sleep disorder that is encountered in practice is delayed sleep phase syndrome (DSPS).

What is delayed sleep phase syndrome?

Delayed sleep phase syndrome is a persistent sleep disorder in which an individual's ability to fall asleep at an appropriate bedtime is delayed causing them to initiate sleep at a much later time. The person who has this syndrome has difficulty maintaining a typical daytime schedule (i.e., work, school) because they are unable to awaken at a normal hour in the morning.

Sometimes DSPS can be mistaken for insomnia, but these two sleep disorders have one major difference and that is quality of sleep. A person with insomnia has a difficult time initiating and maintaining sleep, whereas, someone with DSPS will have no difficulty falling and staying asleep, they just do so at a time considered later than normal. This disorder is more common among adolescents and young adults.

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