Sleep Center Glossary
A
Around the time of puberty onset, teenagers experience a physiologically-based delay in sleep onset (approximately a two-hour delay in sleep onset and wake up times). This delay, combined with certain environmental factors (homework, after school jobs, athletics, busy social schedules and earlier school start times), leads to insufficient sleep and significant sleepiness in many adolescents.
Advanced Sleep Phase Syndrome (ASPS)
Advanced Sleep Phase Syndrome (ASPS) occurs when a person's "body clock" (i.e., circadian rhythm) is set to fall asleep very early in the afternoon. Individuals with ASPS wake up very early (or during the middle of the night) and are unable to fall back asleep.
Having the ability to walk and / or run.
Apnea
Complete cessation of airflow at the nose and / or mouth.
B
Children may engage in any number of behaviors to delay bedtime. Common behaviors include stalling or making excuses ("I need to go to the bathroom.") to avoid going to bed. Other children may get up out of bed soon after getting into bed. Bedtime refusal is characteristic of several different sleep disorders including nighttime fears, limit-setting sleep disorder and delayed sleep phase syndrome.
Breathing Disorders Associated with Neuromuscular Disorders
Certain muscle diseases such as congenital myopathies, muscular dystrophies and hypotonia increase the likelihood of obstructive sleep apnea and sleep disordered breathing.
C
Central Hypoventilation Syndrome
This syndrome is a disorder of the central nervous system in which the control of breathing is absent or impaired. Breathing during waking periods is generally intact but sleeping periods may require mechanical ventilation assistance.
Central Sleep Apnea
Central sleep apnea is a cessation of airflow without any respiratory effort (attempt to breathe).
A prolonged or persistent condition of respiratory (breathing) dysfunction resulting in oxygenation (supply of oxygen) or carbon dioxide elimination (in the circulating blood) at a rate that is not sufficient to meet the demands of the body is called chronic respiratory failure. It may be severe enough to impair or threaten the function of vital organs (respiratory failure).
Circadian rhythms are our bodies natural rhythms that influence a number of biological / physiological processes, such as sleep and wake patterns, body temperature and certain hormonal changes. Circadian rhythms generally follow a cycle that lasts approximately 24 hours.
Most common in infants and toddlers, confusional arousals occur when a person is in a transitional state between sleep and awake. These events may start with crying and thrashing around in bed. If a child is having a confusional arousal, he or she may appear to be awake, confused and upset, but will resist attempts to be comforted or consoled. A confusional arousal may last up to 30 minutes.
Birth defects such as cleft palate (opening in the roof of the mouth in which the two sides of the palate did not join together, as the unborn baby was developing) midface hypoplasia (poorly formed / underdeveloped facial structure) or micrognathia (small lower jaw) may predispose a child to sleep disordered breathing.
D
Delayed Sleep Phase Syndrome (DSPS)
Delayed Sleep Phase Syndrome (DSPS) occurs when a person's "body clock" (i.e., circadian rhythm) is set to fall asleep too late to get sufficient sleep for school or work.
Difficulty Falling Asleep Alone
Children may experience difficulty falling asleep alone if they have not learned the skill to self soothe at bedtime. Children with difficulty falling asleep alone may also have problems maintaining sleep at night. Children with negative sleep associations (e.g., rocking, holding, swinging, nursing) require parental intervention upon waking during the night because they are unable to self soothe and fall asleep independently.
Drinking / Eating Disorder
See Nighttime Eating / Drinking Disorder.
H
Hypercapnia
Hypercapnia is the presence of an abnormally high level of carbon dioxide in the circulating blood.
Hypopnea
Hypopnea is partial (30-50%) cessation of airflow at the nose and / or mouth.
Hypoxemia
Hypoxemia is reduced oxygen in the circulating blood.
I
Insomnia is difficulty falling asleep or staying asleep during the night and may include waking too early in the morning. It is more common in adults than in children and adolescents. Insomnia almost always involves bad sleep habits, such as spending too much time in bed, napping during the day,
J
Jet Lag
Jet lag is a common circadian rhythm disturbance that occurs when a person travels quickly across several time zones. It is likely to occur with international travel and its symptoms may last up to a week or longer while the body adjusts to the new sleep / wake schedule. Symptoms include insomnia, excessive daytime sleepiness, indigestion, irritability and poor concentration.
L
Limit-Setting Sleep Disorder
Limit-setting sleep disorder is more common for children who are fully ambulatory and have developed receptive and expressive language skills (typically after age 2). It is characterized by lack of bedtime limits which results in a delay in going to bed and insufficient sleep.
N
Narcolepsy
Narcolepsy is a serious sleep disorder that can be very disabling. Approximately one in 2000 people has the condition. Individuals with narcolepsy experience constant sleepiness and an ongoing struggle to stay awake. The sleepiness in narcolepsy is so significant that people with the disorder often fall asleep in inappropriate places. The state of sleepiness in narcolepsy often does not improve with increased sleep. If this disorder is not appropriately diagnosed and treated it can be very devastating to the individual's quality of life.
Nightmares are vivid dreams that usually can be recalled after waking up and are often a source of anxiety for young children.
Night Terrors
See Sleep Terrors.
Nighttime Eating / Drinking Disorder
This disorder is more common among infants and toddlers and involves "excessive" nighttime feeding (often nursing or bottle-feeding) that is required in order for the child to fall asleep or return to sleep. For infants, feeding during the night is a normal part of development. However, by the age of five or six months, most children are not drinking more than 8 ounces of fluid during the night (or nursing more than once or twice).
Nighttime Fears
Nighttime fears are common among children and are usually part of normal development. They may occur at bedtime or during the night, and often start during preschool years. The type of fears children experience typically changes as they mature. Young children are often afraid of monsters, while older children may have more realistic fears such as being harmed by a natural disaster.
O
Children who struggle to breathe during sleep may have Obstructive Sleep Apnea (OSA). OSA is when breathing is intermittently blocked during sleep.
Overnight Sleep Study
Overnight sleep studies involve observing a child's sleep in a sleep laboratory in order to better understand problems that could be causing the sleep disorder. A test called polysomnography (PSG) that measures the different stages of sleep is used to help diagnose and classify different sleep problems. Specific measurements of breathing, brain activity, muscle movements, eye movements and leg movements are taken while you are sleeping. The sleep study does not involve any painful procedures.
P
Parasomnias
Parasomnias include a broad spectrum of sleep disorders that most often occur during sleep and are most often infrequent and mild in degree of severity. The most common parasomnias are "disorders of arousal" which include confusional arousals, sleepwalking and night terrors.
Partial Obstructive Hypoventilation Hypopneas
Partial closure of the throat during sleep resulting in reduced air exchange at the level of the mouth and / or nostril. Characterized by snoring, increased respiratory effort and arousals, which result in sleep disturbance and daytime symptoms.
Periodic Limb Movement Disorder (PLMD)
This disorder involves periodic episodes of repetitive movements, usually in the legs, that occur about every 20 to 40 seconds. The movements may appear as brief muscle twitches, jerking movements or an upward flexing of the feet. The movements occur in clusters, lasting from a few minutes to a few hours. Most children with PLMD are not aware of the movements. PLMD can result in frequent brief arousals throughout the night, leading to daytime sleepiness.
Poor Sleep Habits (Inadequate Sleep Hygiene)
This refers to behavioral practices that increase arousal at night and are incompatible with sleep. Inadequate sleep hygiene is the most common cause of difficulties initiating and maintaining sleep. It may include behaviors such as excessive caffeine consumption, frequent napping, excessive time in bed and an irregular sleep-wake schedule.
Primary Snoring
Primary snoring is as an attempt to breathe in the face of increased upper airway resistance without apnea, hypopnea, hypoxemia or significant arousals (3 seconds of wake electroencephalography).
R
Restless Leg Syndrome (RLS)
RLS is a movement disorder in which a child experiences uncomfortable sensations in the legs during rest or sitting still (commonly when trying to fall asleep). The sensations are often described as creepy, crawly, tingling or painful. Children with RLS usually have an "uncontrollable" urge to move their legs (stretching, walking or running, and / or tossing and turning). Rubbing the legs may relieve discomfort. It often takes a long time for a child with RLS to fall asleep at bedtime.
Restless Sleep
Body or limb movements during sleep (i.e., tossing and turning) may be attributed to a number of different sleep problems including insomnia, sleep starts, seizures, anxiety, restless leg syndrome, periodic limb movement disorder or sleep disordered breathing.
S
Sleep Apnea
See Obstructive Sleep Apnea (OSA).
Sleep Disordered Breathing
This term refers to the spectrum of respiratory sleep disorders that includes primary snoring, upper airway resistance syndrome, partial obstructive hypoventilation hypopneas and obstructive sleep apnea.
Sleep Disturbances Associated with Chronic Illness
Sleep problems in pediatric special needs populations are common and often very distressing for families. The sleep disorders in such populations are typically not unique to this group, but occur more frequently and are more severe than the general population. Special needs groups include children with neurodevelopmental disorders such as Down Syndrome. Certain chronic illness conditions (i.e., seizure disorders, brain injury, neuromuscular disorders) increase the risk of sleep disorders in children.
Sleep Onset Association Disorder
Sleep-onset association disorder occurs when your child associates or closely connects his ability to fall asleep with "something in the environment" (such as being held by his or her parent; being rocked to sleep; nursing, drinking, or eating at bedtime; watching television or even sleeping in a parent's or sibling's bed). When this "something in the environment" is absent, your child cannot fall asleep.
Common behaviors resulting from sleep terrors (night terrors) include "blood-curdling" screams, rapid breathing, sweating, extreme agitation and in some cases, aggression. Children experiencing sleep terrors usually have no conscious awareness of the event and generally cannot remember the terror upon awakening. Sleep terrors should not be confused with nightmares.
Sleepwalking is more common in older children and can range from simple behaviors such as getting out of bed to more complex tasks such as leaving the house and walking around outdoors. Sleepwalkers may speak, but usually any talking is not understandable. In children, sleepwalking tends to decrease over time and rarely requires any treatment.
U
Upper Airway Resistance Syndrome
Breathing disorder characterized by repetitive increases in resistance to airflow in the upper airway. Usually associated with loud snoring, brief arousals and daytime fatigue.
V
Ventilator or Technology Dependence
Conditions such as stroke and spinal cord injury damage the nerves that control breathing and make spontaneous breathing impossible for an extended period or for life. Chronic stable illnesses, such as neuromuscular disorders and chest wall deformities, and / or advanced age may make long-term mechanical ventilation necessary for extended periods or for life. Mechanical ventilation is required when a patient's spontaneous efforts are not able to sustain adequate ventilation of the lungs.
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