Sleep Soundly Every Night, Feel Fantastic Every Day (38 page)

(Excessive) Daytime Sleepiness
—being persistently sleepy, lacking energy, even after adequate sleep.

Delayed Sleep Phase Syndrome
—circadian rhythm sleep disorder in which the sleep pattern is delayed two or more hours from a normal bedtime.

Delta Waves
—brain waves with a frequency of 0 hertz to 4 hertz that emanate from the forward frontal lobes portion of the brain during deep sleep in normal adults.

Desynchronization
—when the internal biological clocks are out of phase (or out of sync) with external or environmental signals.

Diurnal
—active or occurring during the daytime; repeating once each 24 hours.

Dreaming
—thoughts, feelings, or images that occur during sleep.

Dyssomnias
—a category of sleep disorders that make it difficult to go to sleep or to stay asleep.

Electroencephalography (EEG)
—a test that measures the brain's electrical activity.

Endocrine System
—the body's system of glands that secrete hormones into the bloodstream.

Endogenous Rhythms
—the internal rhythms driven by the self-sustaining biological clocks.

Entrain
—to reset or align with the biological clock.

Enuresis
—bed-wetting.

Exacerbate
—to aggravate or make severity worse.

Executive Functions (Thinking Skills)
—the mentation enabling a person to link past experiences with present actions such as planning, organizing, strategizing, paying attention to and remembering details, and managing time and space.

Exogenous Rhythms
—rhythms that external cues directly regulate or influence. Cues are not generated internally.

Free-Running Disorder
—a circadian sleep disorder in which environmental cues such as sunset for sleeping do not entrain sleep patterns.

Gene
—a DNA sequence that encodes a protein.

Homeostasis
—the ability of an organism or cell to maintain internal equilibrium by adjusting its internal processes.

Homeostatic Regulation of Sleep
—the neurobiological signals mediating the pressure or urge to sleep.

Hypersomnia
—sleep of excessive depth or abnormal duration, usually caused by psychological rather than physical factors and characterized by a state of confusion on awakening.

Hypersomnolence
—excessive drowsiness.

Hypopnea
—hypopnea is a 30% drop in flow lasting at least 10 seconds accompanied by a 3% drop in oxygen saturation or an arousal from sleep.

Hypothalamus
—the part of the brain that lies below the thalamus and regulates body temperature and metabolic processes.

Insomnia
—sleeplessness with chronic difficulty with sleep onset or maintenance of sleep, or a perception of non refreshing sleep.

Irregular Sleep–Wake Syndrome
—a rare disorder of sleeping without a set schedule because of a problem with brain function or a problem with the body's circadian rhythms (internal clock).

Jet Lag Disorder
—a change or disruption of normal circadian rhythms in transatlantic travel that results from a disparity between the internal clock and the external clock at your destination in desynchronizing the internal clock, as one passes through several time zones.

Kleine-Levin Syndrome
—recurrent episodes of dramatic hypersomnia lasting from two days to several weeks. These episodes are associated with behavioral and cognitive abnormalities, binge eating, hypersexuality, and alternate with long asymptomatic periods that last months to years.

Melatonin
—the pineal gland's secretion of a hormone derived from the amino acid tryptophan, and it synchronizes biological clock neurons in the suprachiasmatic nucleus.

Multiple Sleep Latency Test (MSLT)
—a test for daytime sleepiness.

Narcolepsy
—chronic sleep disorder characterized by excessive and overwhelming daytime sleepiness (even after adequate nighttime sleep) usually associated with a transient loss of muscle tone in response to emotions called cataplexy.

Neurotransmitter
—a chemical produced by neurons that carries messages to other neurons.

Night (Nocturnal) Eating
—the biological clock for eating, the circadian eating cycle is out of phase with the circadian sleep–wake cycle and causes one to consume excessive calories.

Night Terrors
—a disorder of arousal associated with non-REM sleep initiated by a scream associated with panic, followed by intense autonomic activity such as sweating, rapid heart rate, and a terrified appearance. This is due to overactivity of the sympathetic fight-or-flight system. There can be associated motor activity resulting in injury due to running into walls or falling.

Nightmare Disorder
—recurrent nightmares, generally in the REM sleep cycle, that are coherent dream sequences and manifest as disturbing mental experiences.

Nocturnal
—takes place at night.

Nocturnal Groaning
—disruptive groaning that occurs during expiration, particularly during the second half of night.

Non–Rapid Eye Movement Sleep (non-REM)
—deep, dreamless sleep that occurs cyclically during a normal period of sleep and comprises three-fourths of the night's sleep, with intervening periods of REM sleep. Also termed non-REM sleep or slow-wave sleep comprised of sleep stages one, two, and slow-wave.

Obstructive Sleep Apnea (OSA) (Sleep Apnea Syndrome)
—a sleep disorder where breathing is frequently interrupted for brief intervals during sleep, resulting in intermittent decreases in blood oxygen levels and transient arousals from sleep, leading to poor sleep quality and excessive daytime sleepiness.

Parasomnias
—behaviors or experiences that occur during entry into sleep, during sleep, or during arousals from sleep. The behaviors include sleepwalking, sleep talking, and sleep terrors.

Periodic Limb Movements
—rhythmic movement during sleep.

Photoperiod
—the cycle of day and night or light and dark.

Photoreceptor
—a molecule that detects light.

Polysomnogram
—a sleep test that continuously acquires physiological data obtained during sleep, including brain wave activity, eye movements, muscle activity (chin and legs), heart rate, body position, and respiratory variables, including oxygen saturation.

Polysomnography
—recording multiple bodily functions while a person sleeps.

Post-Traumatic Stress Disorder (PTSD)
—a diagnosis of mental and emotional trauma after exposure to or experience of a trauma.

Rapid-Eye-Movement Sleep (REM)
—deep sleep with rapid eye movements in which dreaming takes place.

REM Sleep Behavior Disorder (RSBD)
—complex behaviors, including mild to harmful body movements associated with dreams and nightmares and loss of muscle atonia.

Restless Legs Syndrome (RLS
)—a neurologic movement disorder that is often associated with a sleep complaint.

Seasonal Affective Disorder (SAD
)—a form of depression caused by inadequate bright light.

Sexsomnia
—when a person engages in sexual activities while asleep.

Shift Work Sleep Disorder
—a circadian rhythm sleep disorder with insomnia and excessive sleepiness affecting people whose work hours are typically the night shift.

Sleep Apnea
—a disorder of periodic stops in breathing during sleep caused by either an obstruction of the airway or a disturbance in the brain's breathing center.

Sleep Attacks
—the sudden need or desire to go to sleep.

Sleep Deprivation
—the disorder of not having adequate sleep.

Sleep Drunkenness
—a problem in waking up and being confused for long periods of time after waking. Also known as sleep inertia.

Sleep Hygiene
—the practice of maintaining proper sleep health.

Sleep Medicine
—the medical specialty applied to the diagnosis and treatment of persons with chronic sleep loss or sleep disorders.

Sleep Paralysis
—muscle paralysis akin to sleep atonia (REM sleep) while awake, when falling asleep, or waking up.

Sleep-Related Dissociative Disorder
—dissociative episodes that can occur in the period from wakefulness to sleep or from awakening from stages 1 or 2 or from REM sleep.

Sleep-Related Eating Disorder (SRED)
—repeated episodes of involuntary eating and drinking during arousals from sleep.

Sleep-Related Hallucination
—hallucinatory images that occur at sleep onset or on awakening from sleep.

Sleep Restriction Therapy
—a technique that restricts time in bed to the actual sleep time, which creates mild sleep deprivation and results in more efficient sleep.

Sleep Spindle
—the hills and valleys of electrical brain activity at 7 to 14 Hz, grouped in sequences that last one to two seconds and recur periodically with a slow rhythm of 0.1 to 0.4 Hz.

Sleepwalking
—a disorder of arousal in non-REM sleep involving a series of behaviors initiated during arousals from slow-wave sleep that culminate in walking around in an altered state of consciousness.

Slow-wave Sleep (SWS
)—sleep stages characterized by slow waves.

Sleep Stages
—sleep cycles in which different brain wave patterns are displayed.

  
Stage 1—first stage of non-REM sleep characterized by low-voltage, mixed-frequency waves on the EEG; small, slow eye movements, and tonic muscles.

  
Stage 2—cycle of non-REM sleep characterized by low-voltage, mixed-frequency waves on the EEG, sleep spindles, and K-complexes; occasional small eye movements near sleep onset; and tonic muscles.

  
Stage 3—cycle of non-REM sleep characterized by high-voltage, slow-wave activity on the EEG; no eye movements; and tonic muscles.

Stimulus Control
—technique to disrupt sleep, thus preventing associations with the bedroom by enhancing the likelihood of sleep.

Suprachiasmatic Nucleus (SCN
)—the small area within the hypothalamus that contains the biological clock.