Polysomnography Terms

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delta waves

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brain waves with a frequency of 1 to 3 hertz that emanate from forward portion of brain.

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desynchronization

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misalignment of external signals & biological clock, cause of many circadian disorders.

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diagnostic sleep study

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monitoring, either in a sleep lab or patient’s home with portable device, of several physiologicalactivities; performed to test for a specific sleep disorder.

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dopamine

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mineinhibitory neurotransmitter involved in voluntary movement and motivation.

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electroencephalogram (EEG)

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a measurement of the electrical activity associated with brain activity.

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electromyogram (EMG)

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a measurement of the electrical activity associated with muscle movements.

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electrooculogram (EOG)

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a measurement of the electrical activity associated with eye movements.

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entrain

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to reset or align with the biological clock.

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epworth sleepiness scale

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a scale indicating propensity to sleep during the day as perceived by patients from the subjectiveanswers to eight questions.. It has the benefits of being fast and simple.

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excessive daytime sleepiness (EDS)

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subjective report of difficulty in staying awake, accompanied by ready entrance into sleep whensedentary. Suggests presence of a sleep disorder and is different from fatigue

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free-running disorder (FRD)

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a circadian disorder where the sleep cycle becomes detached from the normal patterns. Oftenafflicts blind people

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GABA (Gamma-Aminobutyric Acid)

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an amino acid neurotransmitter (C4H9NO2) in the brain believed to be involved in musclerelaxation, sleep, diminished emotional reaction and sedation.

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homeostatic regulation of sleep

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refers to the neurobiological signals mediating the pressure or urge to sleep.

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hypersomnia

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excessive sleep, characterized by recurrent episodes of unusual daytime sleepiness or prolongednighttime sleep. Persons with hypersomnia are compelled to nap repeatedly during the day, oftenat inappropriate times>

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hypnagogic hallucination

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a “greater-than-life-like” dream experience. Sometimes associated with narcolepsy.

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hypnic jerk

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a startle reaction as a person falls asleep; muscle jerks like an electric shock. Normal. Everyoneexperiences them. Also called a sleep start or a hypnagogic jerk.

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hypnogram

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a graphical summary of the electrical activities occurring during a night's sleep.

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hypnotics

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medications that cause sleep or partial loss of consciousness.

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hypocretin

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peptide involved in sleep cycle. Also called orexin.

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imidazopyridines

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class of drugs prescribed for insomnia. Often called nonbenzodiazepines. Imidazopyridinesinclude zolpidem (Ambien) and alpidem.

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insomnia

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difficulty in sleeping that may include difficulty falling asleep, waking often during the night withtrouble going back to sleep, waking up too early or un-refreshing sleep.

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jet lag

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describes a combination of symptoms (fatigue, irritability, dehydration, and broken sleep pattern)induced by a major rapid shift in environmental time in travel to new time zone.

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light therapy

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form of therapy where the person is exposed to bright light at the appropriate time of day to effectthe timing, duration and quality of sleep. Also used in the treatment of Seasonal AffectiveDisorder.

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melatonin

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a hormone secreted by the pineal gland that is derived from the amino acid tryptophan, whichhelps synchronize biological clock neurons in the suprachiasmatic nucleus.

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micro-arousal

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partial awakening from sleep. An episode where a sleeper partially awakes, but is not aware of it .

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micro-sleep

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period lasting up to a few seconds during which people appear to be asleep in otherwise wakingperiods. Cause for concern for people in critical jobs like truck drivers or pilots.

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multiple sleep latency test (MSLT)

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a sleep test given at sleep labs in the diagnosis of sleep disorders. The test records brain waves,heart rate, muscle activity and eye movements and given by series of "nap tests".

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narcolepsy

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sleep disorder characterized by brief attacks of deep sleep, and with symptoms includingexcessive sleepiness, cataplexy, sleep paralysis, hypnogogic hallucinations, overwhelmingdaytime sleepiness (even after adequate nighttime sleep), and an abnormal tendency to passdirectly from wakefulness into REM sleep.

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natural short sleeper

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Person who habitually and spontaneously sleeps substantially less in a 24-hour period than isexpected for a person in his or her age group, without excessive sleepiness.

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neuromodulator

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compounds with classical “endocrine” functions. Affect the brain in a fashion that is notdependent upon the presence of the appropriate endocrine or physiological target organ.

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neurotransmitter

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

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nightmare

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areunpleasant and/or frightening dream. Unlike night terrors, nightmares occur during REM sleep.

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night terrors

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also known as sleep terrors, or pavor nocturnus. Incomplete arousal from slow wave sleepaccompanied by a state of intense fear and agitation.

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nocturia

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aurination at night especially when excessive

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nocturnal

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relating to or taking place at night.

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nocturnal sleep-related eating disorder (NS-RED)

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eating while sleepwalking. Typically the person doesn't remember eating when awaken

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nocturnal enuresis

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Bedwetting. Urinating during sleep

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NREM

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non-REM sleep - a normal part of sleep accounting for typically 75-80% of sleep time.Characterized by slower and larger brain waves than in REM.

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obstructive sleep apnea (OSA)

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a disorder in which breathing is frequently interrupted for brief intervals during sleep, resulting inintermittent decreases in blood oxygen levels and transient arousals.

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orexin

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protein neurotransmitter or neuropeptide active in the sleep cycle and in appetite. Deficiency isassociated with narcolepsy.

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parasomnias

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disorders that intrude into the sleep process and create disruptive sleep-related events. Thesebehaviors and experiences occur usually during sleep.

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partial agonist

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drug that causes functional effect that is only a fraction of that of the endogenous ligand

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phase advance

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a shift earlier in time, for instance going to bed earlier and waking up earlier.

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phase delay

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a shift later in time, for instance going to bed later and waking up later.

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polysomnogram (PSG)

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continuous and simultaneous recording of physiological variables during sleep, i.e., brain waves,major muscle activity, eye movement, heart activity, respiratory air flow, respiratory excursion,lower limb movement, and other electrophysiological variables.

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polysomnograph

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a test of sleep cycles and stages through the use of continuous recordings of physiologicalvariables (see polysomnogram above), and direct observation of the person during sleep.

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obesity-hypoventilation syndrome

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a condition related to obstructive sleep apnea in which a very obese person does not breathesufficient air during sleep or while awake. Also called Pickwickian syndrome.

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obstructive apnea

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apnea due to a mechanical obstruction, such as a very large uvula or tongue in the back of themouth, or a problem with the trachea.

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rebound insomnia

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sleep difficulties after discontinuing use of a hypnotic medication.

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REM latency

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period of time from sleep onset to the first appearance REM.

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REM motor atonia

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when the large skeletal muscles go limp during REM sleep.

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REM period

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REM portion of a NREM-REM cycle; early in the night it may be as short as a half-minute,whereas in later cycles longer than an hour

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REM sleep behavior disorder (RBD)

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very rare disorder in which sleeper acts out dreams, often violently, and has bodily movement.The body is usually paralyzed during REM sleep. Patients often report an ongoing, hallucinatoryREM dream episode. May be a warning sign of Parkinson's. Often linked to neuropathologies(i.e.vascular insult, tumors, brain degenerative disorders).

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rapid eye movement (REM) sleep

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deep sleep period with rapid eye movements. Normal part of sleep cycle recurs several timesduring normal sleep period. Increased neuronal activity of the forebrain and midbrain &depressed muscle tone. 20% of sleep, most dreaming occurs in this stage.

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REM sleep rebound

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increase in REM sleep following unnatural reduction. Extension of time in, and an increase infrequency and density of REM sleep episodes.

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restless legs syndrome (RLS)

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sleep disorder with a deep creeping/crawling sensation in the legs even when not moving. Nearlyirresistible urge to move the legs; the sensations are relieved by movement.

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seasonal affective disorder (SAD)

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a form of depression caused by inadequate bright light reaching the biological clock in thesuprachiasmatic nucleus. Treatment often involves the use of light therapy.

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sedatives

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chemicals tending to reduce nervousness or excitement and foster sleep. Many sleep medicinesare sedatives. Sedation can be side effect of drugs given for other purposes.

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serotonin

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neurotransmitter involved in several important body functions such as memory, emotions, moods,sleep and arousal.

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sleep

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the natural periodic suspension of consciousness during which the powers of the body arerestored, characterized by lessened consciousness and slowed-down metabolism

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sleep apnea

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sleeper repeatedly stops breathing for 10 or more seconds during sleep. The three types areobstructive, central, and mixed; of the three, obstructive is the most common

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sleep architecture

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NREM/REM stage and cycles of sleep and time spent in each stage. One's sleep architecturechanges with age. Older people tend to spend less time in deeper sleep than younger people. By60 or 70, many adults experience a decrease in the proportion of time spent in delta sleep. Thepercentage of REM sleep remains relatively stable.

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sleep cycle

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term used to describe the pattern of sleep stages, especially the NREM-REM cycle

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sleep debt

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physiological state that results from recurrent sleep deprivation occurs over time.

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sleep deprivation

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acute or chronic lack of sufficient sleep.

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sleep disorders

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general term broad range of illnesses, including dysfunctional sleep mechanisms, abnormalphysiological function, biological clock abnormalities, and sleep disturbances

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sleep disordered breathing

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group of disorders that produce pauses in breath in sleep or that reduce the amount of air theperson is getting. Apnea is a common type.

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sleep efficiency

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refers to the proportion of time in bed that is spent sleeping. Also called "sleep onset latency".

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sleep fragmentation

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sleep interruption due to frequent or sustained awakenings or early morning awakenings

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sleep hygiene

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conditions and practices that promote continuous and effective sleep, including bedtime routines,regular bed and arise time, and getting enough sleep to avoid sleepiness during the day. Can alsorefer to limiting alcoholic and caffeinated prior to bedtime and using exercise, nutrition, andenvironmental factors to enhance, not disturb, restful sleep

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sleep hyperhidrosis or sleep hyperhydrosis

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profuse sweating during sleep

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sleep inertia

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grogginess lasting longer than 10-20 minutes after waking. Symptoms are transitory"hypovigilance" or low vigilance, confusion, disorientation, impaired cognitive/sensory-motorperformance. Typically when aroused from deep sleep in the first part of the night

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sleep latency

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time between going to bed and sleep onset. "REM sleep latency" is time between sleep onset andonset of first episode of REM sleep.

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sleep maintenance

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the ability to remain asleep for a long period of time

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sleep paralysis

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temporary inability to talk or move when falling asleep or waking up

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sleep talking

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speech or sounds during sleep without awareness or memory. During REMS and is a motorbreakthrough of dream speech, or transitory arousals from NREMS & other stages.

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sleepiness

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somnolence, drowsiness -. Differs from simply feeling physically tired or listlessness.

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sleepwalking

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pwalkingsomnambulism. Sleep disorder where the person gets out of bed and walks around during sleep.Typically in the first third of the night during deep NREM sleep (stages 3 and 4).

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somniloquy

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talking while asleep

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somnipathy

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sleep disorder

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somniphobia

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fear of sleep, fear of falling asleep. Possibly related to anxiety disorder.

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snoring

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noise produced with inspiratory respiration during sleep owing to vibration of the soft palate andthe pillars of the oropharyngeal inlet. More frequent in males and overweight persons worseningwith age. Problem snorers may develop OSA.

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suprachiasmatic nucleus (SCN)

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the part of the brain (in the hypothalamus) that contains the biological clock for the circadiancycle.

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thalamus

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part of the brain consisting of two large ovoid structures at base of the cerebrum. It acts as a vitalrelay station between the sensory nerves and the cerebral cortex.

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transient insomnia

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non-chronic insomnia, usually lasting less than three weeks.

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uvulopalatopharyngoplasty (UPPP)

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an operation removing soft tissue in back of throat and soft palate (uvula) to treat severe snoringand sleep apnea. Tonsils and other excess tissue may also be removed, if present.

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zeitgebers

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German for "time givers". External cues that affect the Circadian cycle. Examples includesunlight, familiar morning noises and sounds, and meals.