SLEEP MEDICINE FELLOWSHIP | Neurology

Sleep is critically important for health and happiness, yet sleep is often neglected and its importance underappreciated in our busy society. About one of every four Americans has a sleep problem. If you are sleeping too much, experiencing excessive daytime sleepiness (falling asleep at inappropriate times), having difficulty falling or staying asleep, or experiencing abnormal behaviors associated with sleep, you may have a sleep disorder.

Snoring and sleep apnea are sleep-related breathing disorders that involve abnormal breathing during sleep.

Snoring

When the airway becomes partially blocked, some of the inhaled air becomes redirected from the lungs to the mouth, producing a pressure that vibrates the soft tissue of the palate, resulting in snoring.
Snoring is associated with disrupted sleep, daytime fatigue and sleepiness, and low oxygen levels in the body. Snoring can also seriously disturb the bed partner’s sleep, resulting in difficulties in interpersonal relationships.

Obstructive Sleep Apnea

The soft tissues in the throat relax during sleep. Obstructive sleep apnea (OSA) occurs when the airway repeatedly collapses during the night, either completely or partially, thereby disrupting breathing. When the airway is blocked, the oxygen levels in the body drop, causing the person to awaken and begin breathing normally. The affected person often is unaware of the awakenings because they may last only a few seconds. Someone with severe sleep apnea may awaken hundreds of times during the night. The awakenings fragment and interrupt the sleep cycle, which causes the common symptoms of sleep apnea, daytime fatigue and sleepiness. OSA is a treatable disease, but if untreated it is associated with serious medical conditions.
Symptoms of OSA in adults include:

• Snoring

• Choking or gasping during sleep
• Observed pauses in breathing
• Daytime fatigue and/or sleepiness
• Dry and/or sore throat in the morning
• Morning headaches
• Night sweats
• Insomnia
• Poor concentration and attention
• Memory problems
• Anxiety
• Irritability
• Sleepwalking or night terrors

Symptoms of sleep apnea in children include:

• Snoring
• Daytime cognitive and behavioral problems including problems paying attention, easy distractibility, aggressive behavior, and hyperactivity
• Mouth breathing
• Enlarged tonsil and adenoids
• Problems sleeping and restless sleep
• Parasomnias such as sleepwalking or night terrors
• Bedwetting
• Failure to thrive
• Excessive daytime sleepiness
• Upper airway resistance syndrome is a condition in which the throat becomes blocked, resulting in periodic episodes of reduced air flow. Although the resulting disturbance of sleep is not as great as that associated with OSA, upper airway resistance syndrome can cause similar symptoms.

Other Sleep-Related Breathing Disorders

Other sleep-related breathing disorders include central sleep apnea (CSA) and sleep-related hypoventilation syndromes (SHS). CSA occurs when the brain fails to signal the body to breathe. Unlike obstructive sleep apnea, in CSA there is no breathing effort because there is no drive to breathe. SHS are the result of a decreased response to low oxygen or high carbon dioxide during wakefulness and sleep. The syndromes are characterized by frequent episodes of shallow breathing during sleep that last longer than 10 seconds.

Diagnosis

A comprehensive history and physical examination by a sleep physician and an overnight sleep study is needed to diagnose sleep-related breathing disorders in children or adults.
 

Insomnia

Insomnia is a common sleep disorder that affects about 10% of the adult population. The nighttime symptoms include persistent difficulty falling and/or staying asleep. Daytime symptoms include fatigue, and difficulties with concentration and/or memory. Insomnia may be diagnosed when symptoms persist for at least a month.
Insomnia sometimes occurs alone, with no other co-existing disease. But more often insomnia occurs in conjunction with other medical or psychiatric conditions, and may worsen them or hinder their treatment. For example, people with depression and insomnia do not respond as well to depression treatment as depressed people without insomnia.

Risks for Insomnia

The known risk factors include:

• Absence of a regular wake time
• Excessive worry
• Failure to unwind from the day’s stresses
• Other sleep disorders, including restless legs syndrome and sleep apnea
• Genetic predisposition
• Gender: Women are twice as likely as men to experience insomnia
• Age: Older adults are more likely to experience insomnia

Diagnosing Insomnia

An insomnia disorder is diagnosed when the disturbed sleep lasts more than a month and negatively impacts general well being, either because the difficulty in sleeping is particularly distressing or because it leads to an impairment in performance or mood. Part of the diagnosis involves a determination of whether the symptoms are better explained by other medical or psychiatric conditions.
 

Circadian Rhythm Disorders

The internal activity of the human body follows a cyclic pattern called a circadian rhythm. Chemical and electrical signals are generated during the cycle that tend to produce sleep at night and wakefulness during the day. The rhythm works best when a reasonable amount of exposure to sunlight is obtained and regular routines for going to bed in the evening and awakening in the morning are maintained. Disorders involving the rhythm occur when it becomes misaligned with a person’s chosen time for sleeping and waking. Various types of disorders are recognized, the most common of which are delayed sleep-phase, advanced sleep-phase, and a disruption of the rhythm that results from shift work.

Delayed sleep-phase occurs when the timing of the internal signal for sleep is delayed several hours relative to a person’s desired bedtime. People with this disorder have difficulty falling asleep because their internal clocks do not send the signal for sleep until late into the night. They also have difficulty waking up at what is generally considered a normal time because their natural awakening is delayed. Someone with delayed sleep-phase may sleep well but wakes up late, making it difficult to begin a typical daily routine of activity in a timely fashion. People are not considered to have delayed sleep-phase disorder unless they also experience impairment in social, occupational, or other areas of life as a consequence of the sleep problem.

Advanced sleep-phase disorder is produced when the sleep signal occurs several hours or more earlier than the desired bedtime. People with this disorder go to bed and awaken unusually early because their sleep and awakening signals are mis-timed relative to their desired schedules. The disorder makes it difficult to engage in social activities because of the need to go to sleep much earlier than what is generally considered normal. Advanced sleep-phase is particularly prevalent among older adults.

Shift-work sleep disorder is a problem that stems from the mismatch between a person’s circadian rhythm and the time interval for sleep that fits a particular work schedule. Symptoms produced by the mismatch may include difficulty in initiating and maintaining sleep, excessive sleepiness when awake, difficulty concentrating, headaches, and/or a general feeling of malaise. Rotating shifts are particularly a problem because they may lead to trouble staying alert while working, and to unrefreshing sleep.
 

Restless Legs Syndrome

Restless legs is a common syndrome in which a person has an urge to move the legs and, typically, experiences abnormal sensations including burning, tingling, or aching. The arms or other body areas may also be affected. The symptoms can range from mild to severe, and may occur occasionally or almost every evening. The disorder is about twice as common in women, and its prevalence increases with age.

The symptoms of restless legs syndrome (RLS) start or worsen during rest, especially in the evening and/or when lying down. The longer someone rests, the greater the chances the symptoms will occur and will be more severe. The symptoms improve as a result of movement. At least partial relief typically starts soon after beginning activities such as walking, and persists as long as the activity continues.

Most people with RLS also demonstrate periodic limb movements during sleep, which are abrupt leg movements that occur 20 to 30 seconds apart at various times during the night. The movements, which can also occur in other parts of the body, cause partial awakenings that disrupt sleep, resulting in poor sleep quality.

Low brain iron metabolism and abnormal levels of dopamine in the brain are probably important factors in causing RLS. The disorder commonly runs in families, especially when it is severe and starts early in life. Environmental factors and other medical problems are also associated with the disorder. RLS frequently begins or becomes worse during pregnancy, and is more frequent in people with damaged nerve endings, such as in those with diabetes. RLS may be associated with other conditions such as depression and heart disease.

The disorder may be difficult to diagnose in children because the symptoms overlap those of other pediatric disorders.
 

Pediatric Disorders

Sleep disorders can occur in infants, young children, and adolescents, resulting in developmental, behavioral, and social difficulties, and in other health problems. Children may suffer from problems falling or staying asleep, obstructive sleep apnea, restless legs syndrome, abnormal behaviors during sleep such as sleepwalking or other parasomnias, or from daytime sleepiness. Additionally, many medical or psychiatric conditions can contribute to sleep disorders. The symptoms shown by children may be quite different compared to those of adults with sleep disorders, because developmental aspects of childhood play an important role in pediatric sleep. 

Arousal Disorders

An arousal occurs when a child transitions from deep sleep to light sleep or partial wakefulness. During the arousal the child may appear to be alert, as evidenced by crying or walking, while simultaneously appearing to be disoriented and confused, as evidenced by unresponsiveness to parental directions or environmental challenges. A child who is awakened during an arousal typically does not recall the events that occurred during the episode.
Many kinds of behaviors may be exhibited ranging from mumbling or sitting up in bed during sleep to more elaborate behaviors including loud, distressful crying, ignoring parental directions and reassurances, and a dreamlike expression. The child may act aggressively and regard the parent as a threat. Sleepwalking and running into furniture can occur, which may appear either goal-oriented or without purpose.

Commonly only one episode occurs during the night, often within the first two hours of falling asleep, but multiple episodes are possible. There may be periods when multiple episodes occur each night followed by periods without a single episode. Overall, the timing frequency, intensity, and behavior exhibited are all quite variable.

In older teenagers, alcohol intake and sleep deprivation are possible triggers for arousals. Sometimes the aberrant behaviors are triggered by sleep-disordered-breathing, abnormal sleep-wake schedules, and/or stressful conditions.

Medical and Psychiatric Conditions

Sleep disturbances can occur as a consequence of many different conditions including:

• Attention deficit hyperactivity disorder
• Gastroesophageal reflux disease
• Developmental disorders
• Mental retardation
• Prader-Willi syndrome
• Tourette disorder
• Nocturnal asthma
• Depressive disorders
• Neuromuscular disorders
• Nocturnal seizures
• Kleine-Levin syndrome
• Chronic fatigue syndrome
• Headaches

Diagnosing Pediatric Sleep Disorders

If you suspect your child has a sleep disorder, you should schedule an appointment for an evaluation.
 

Hypersomnias

Hypersomnias are disorders that involve excessive sleep and difficulty in staying awake during the day. The core symptom is excessive daytime sleepiness that is not due to other identifiable causes. Persistent sleepiness lasting more than three months without abnormalities specifically related to REM sleep is called idiopathic hypersomnia. A pattern of periodic isolated episodes of sleepiness is called recurrent hypersomnia.

Idiopathic Hypersomnia

Persons with idiopathic hypersomnia sleep far more than normal, have difficulty waking up, and feel tired, sleepy, or groggy during the day, and experience these symptoms more or less continuously for three months or more with a resulting significant impact on daily life. A diagnosis of idiopathic hypersomnia requires exclusion of other causes of daytime sleepiness such as insufficient sleep, disturbed nocturnal sleep, insomnia, circadian rhythm disorder, sleep-related breathing disorders, or medical issues.
Idiopathic hypersomnia can have many causes including brain abnormalities, low-grade infections, or a brain imbalance associated with psychiatric conditions. The disorder may arise from an abnormal sleep schedule, or sedative or stimulant medications taken in excess or at the wrong time.

Recurrent Hypersomnia

Recurrent hypersomnia is characterized by recurrent, reversible episodes of hypersomnia, often associated with other symptoms, that typically occur weeks or months apart. During the episodes the sufferers experience extreme sleepiness and have big sleep requirements, sometimes as much as 16 to 20 hours a day.
 

Narcolepsy

Narcolepsy is a chronic neurological sleep disorder characterized by excessive daytime sleepiness, and abnormal REM sleep. A person with narcolepsy will experience a high level of fatigue and may fall asleep at odd and inappropriate times, such as during work or school. A brief nap may be refreshing, but the sleepiness can reoccur after a few hours.
Most patients with narcolepsy also experience cataplexy, which is a sudden feeling of paralysis or weakness in the head, legs or other body parts especially after excitement or laughing.
In most cases of narcolepsy without cataplexy, the cause of the symptoms is unclear and the diagnosis is based on the results of a sleep study.