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Glossary of Terms

Advanced Sleep Phase Syndrome:  Sleeps and wakes too early; usually in aging adults

Bruxism:  Teeth grinding that disrupts sleep. Learn More...

Cataplexy:  A symptom of cataplexy includes a loss of muscle tone that leads to feelings of weakness and a loss of voluntary muscle control.

Central Sleep Apnea:  Brief cessations in breathing during sleep, caused by a central nervous system or cardiac dysfunction, with excessive daytime sleepiness, snoring, awakening with shortness of breath.  This is a sleep disorder in which the airway is not blocked but the brain fails to signal the muscles to breathe.

Chronotherapy:  This is a behavioral technique in which bedtime is systematically adjusted. It is  used in cases when the patient’s sleep-wake pattern is out-of-synch with the external environment.

Circadian Rhythms:  These biological rhythms include the internal "clock," which influences when, how much, and how well people sleep.

Cognitive Therapy:  In some cases of insomnia, this therapy includes interventions that are meant to help people identify and correct inappropriate thoughts and beliefs that might contribute to insomnia.

CPAP (Continuous Positive Airway Pressure):  This is an effective treatment for sleep apnea patients. It delivers air into airways through a specially designed nasal mask or pillows.

Delayed Sleep Phase Syndrome:  Sleeps and wakes too late, usually in teens.

Delta Sleep:  Also called slow-wave sleep, this deep sleep occurs in stage N3 of NREM sleep.

Fibromyalgia:  Muscular pain affecting sleep, usually in women.

Gastroesophageal Reflux:  Heartburn and regurgitation of stomach contents during sleep.

Hypersomnia:  Extreme daytime sleepiness.

Idiopathic Hypersomnia:  Extreme daytime sleepiness and extreme difficulty awakening from sleep and post-awakening confusion.

Inadequate Sleep Hygiene:  Bad sleep habits that keep your sleep from being refreshing.

Insomnia:  Difficulty falling asleep, waking and inability to return to sleep, waking too early or un-refreshing sleep. Learn More...

Jet Lag:  Disturbed sleep, decreased alertness and impaired daytime function due to time zone travel. Learn More...

Mixed Sleep Apnea:  This is a combination of central sleep apnea and obstructive sleep apnea.

Multiple Sleep Latency Test (MSLT):  This test assesses the severity of sleepiness by measuring the speed of falling asleep.

Narcolepsy:  This is a neurological condition in which people experience excessive sleepiness with uncontrollable urge to fall asleep, cataplexy, sleep paralysis, hallucinations, and intermittent, uncontrollable sleep attacks during the daytime. Learn More...

Nightmares:  Frightening dreams that can be recalled.

Nocturnal Enuresis:  Chronic bedwetting.

Nocturnal Hyperphagia:  Eating while asleep.

Non 24-Hour Sleep-Wake Disorder:  This is a circadian rhythm disorder, usually seen in blind people, in which the sleep-wake pattern does not conform to the usual 24-hour cycle.

Non-Rapid Eye Movement (NREM) Sleep:  This is one of the two basic states of sleep. It consists of stages 1, 2 (light sleep) and 3,4 (deep sleep).

Obstructive Sleep Apnea (OSA):  Brief cessations in breathing during sleep, caused by a physical obstruction, with loud snoring, excessive daytime sleepiness, morning headaches.  This is the most common kind of sleep apnea. It is caused by a blockage of the upper airway. Learn More...

Panic Disorder:  Awakening with chest pain that brings on panic attacks.

Parasomnias:  These are abnormal behaviors that occur during sleep that interrupt sleep and can result in injury, insomnia, and/or excessive daytime sleepiness.

Periodic Limb Movement Disorder (PLMD):  This is a disorder in which rhythmic jerking of the legs interrupts sleep, causing insomnia and/or excessive daytime sleepiness. Learn More...

Polysomnography:  This is a test that records sleep architecture (such as the amount of NREM and REM sleep, number of arousals) and a variety of body functions during sleep, including breathing patterns, heart rhythms, and limb movements.

Progressive Muscle Relaxation (PMR):  This is a relaxation method that involves tensing and relaxing muscles of the body in a given order, ultimately to achieve relaxation of the whole body. It is useful in some cases of insomnia.

Rapid Eye Movement (REM) Sleep:  REM is one of the two basic states of sleep. REM sleep, also known as "dream sleep," is characterized by rapid eye movements, and more irregular breathing and heart rate compared to NREM sleep.

REM Behavior Disorder:  Acting out dreams with limb movements while asleep.

Restless Legs Syndrome:  Creeping, crawling, tingling or aching sensation in the leg(s) that occur just before falling asleep that create an irresistible urge to move leg(s). Learn More...

Rhythmic Movement Disorder:  Repetitive, and sometime harmful, movements during sleep (head banging, body rocking, head rolling, etc.).

Shift Work Sleep Disorder:  Sleep problems occurring from change of sleep cycle. Learn More...

Sleep Apnea:  This is a serious sleep disorder that occurs when a person’s breathing is interrupted during sleep. Learn More...

Sleep Hygiene:  This refers to the practices, habits, and environmental factors that are important for getting sound sleep. Learn More...

Sleep Hyperhidrosis:  Extreme sweating while asleep.

Sleep Paralysis:  This is a symptom of narcolepsy. It involves the temporary inability to move or speak while falling asleep or waking up.

Sleep Terrors:  Frightening dreams that can't be remembered. Learn More...

Somnambulism:  Walking/performing activities while asleep. Learn More...

Somniloquy:  Talking during sleep.