Definitions and Abbreviations
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A B C
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Movement - In diagnostic sleep studies, abdominal movement
is recorded. This is one of the measures of respiratory effort, reflecting
movement of the diaphragm.
Advanced Sleep Phase Syndrome (ASPS)
- Phases of the daily sleep/wake cycle are advanced with respect to clock
time. This is classified as a circadian rhythm disorder. The sleep phase
occurs well ahead of the conventional bedtime and the tendency is to wake
up too early.
rhythm - EEG oscillations, prominent over the occipital cortex, with
a frequency of 8-13 Hz in adults; indicative
of the awake state; present in most, but not all, normal individuals; most consistent and predominant during relaxed wakefulness.
intrusion - brief occurrence of alpha activity during a stage of sleep.
Monitor - Portable system used to record (continuously) multiple physiological
variables during sleep.
- Literally means "no breath", the cessation of airflow at the nostrils and mouth for at least 10
index (AI) - A measure of the severity of sleep apnea; the number of apnea events per hour.
index (AHI) - the number of apneas and hypopneas per hour. 5-20=mild,
21-50=moderate, above 51 severe
- abrupt change from sleep to wakefulness, or from a "deeper"
stage of non-REM sleep to a "lighter" stage
Disorder - parasomnia disorder presumed to be due to an abnormal arousal
function. Classical arousal disorders:
sleepwalking, sleep terrors and confusional arousals.
Threshold - ease that a sleeping person is awakened.
- irregularity or absence of the heart rhythm caused by disturbances in
transmission of electrical impulses through cardiac tissue.
Auto Adjusting Continuous Positive Airway
Pressure Device (SmartPAP) (Auto-PAP) - A type of CPAP machine monitoring
changes in breathing and compensates automatically by making appropriate
adjustments in pressure.
- automatic action - especially any action performed apparently without intention
Sleep Cycle - progression through orderly succession
of sleep states and stages. For the healthy adult, the first cycle is begins
by going from wakefulness to non-REM sleep. The first REM period follows
the first period of non-REM sleep, and the two sleep states continue to
alternate throughout the night with an average period of about 90 minutes.
A night of normal human sleep usually consists of 4-6 non-REM/REM sleep
Benzodiazepines - developed in the 1950's,
this class of compounds tranquilize and sedates.
Activity - brain waves with a frequency of greater than 13 Hz (Hertz).
Bi-Level - Bi-level pressure device
used to treat sleep apnea. The "bi" refers to two pressures: a lower pressure for exhalation and a higher pressure for inhalation. Bi-Level
machines are more expensive than a standard CPAP, but some patients tolerate
it better because they can exhale comfortably against the constant inhalation
pressure. (Sometimes called Bi-PAP, but that is a trademark name
of one system)
Clock - term for the brain process causing us to have 24-hour fluctuations
in body temperature, hormone secretion, and other bodily activities. The
most important function fosters the daily alternation of sleep and wakefulness.
The biological clock is found in a pair of tiny bilateral brain areas called
the suprachiasmatic nuclei.
Position - four positions are identified which a patient may be sleeping;
back, left side, right side or abdomen. The time spent sleeping in each
position and the number of respiratory events in a particular position are
- heart rhythm with a rate lower than 60 beats per minute in an adult.
Waves - the brain’s spontaneous electrical activity studied by electroencephalography
Bruxism - teeth grinding during sleep
Arrest - sudden cessation of the heart beat.
- Pertaining to blood vessels and
- sudden, dramatic decrement in muscle tone and loss of deep reflexes that
leads to muscle weakness, paralysis, or postural collapse. Usually caused by outburst of emotion: laughter, startle, or sudden physical exercise;
one of the tetrad of symptoms of narcolepsy.
apnea - absence of airflow and inspiratory effort; apnea caused by irregularity in the brain's control of breathing.
Nervous System (CNS) - brain and spinal cord.
respiration - breathing pattern typified by regular "crescendo-decrescendo"
or waxing and waning fluctuations in respiratory rate and tidal volume.
- treatment for circadian rhythm sleep disorder by systemically changing
sleeping and waking times to reset the biological clock.
Circadian rhythm - innate, daily, fluctuation
of behavioral and physiological functions, including sleep waking, generally
tied to the 24 hour day-night cycle but sometimes to a different (e.g.,
23 or 25 hour) periodicity when light/dark and other time cues are removed.
- adhering to or conforming with a regimen of treatment such as CPAP
- Continuous Positive Airway Pressure;
the device used to treat sleep apnea by sending positive airway pressure
at a constant, continuous pressure to help keep an open airway, allowing
the patient to breathe normally through his/her nose and airway
Pressure - pressure needed to maintain an open airway in a sleep apnea
patient treated with CPAP, expressed in centimeters of water (cm H20). The
positive pressure can range from 5 - 20 cm H20. Different patients require
different pressures. The value is determined in a CPAP titration study.
Sleep - refers to combined non-REM sleep stages 3 and
4 in sleep studies
sleep phase - A condition occurring when the clock hour at which sleep
normally occurs is moved back in time in a given, 24 hour sleep-wake cycle.
The result is a temporarily displaced (delayed) occurrence of sleep within
the 24 hour cycle.
sleep - stage(s) of sleep in which EEG delta waves are prevalent or
predominant (sleep stages 3 and 4, respectively).
waves - EEG activity with a frequency less than 4 Hz. In human sleep stage scoring, conventionally the minimum criteria
for scoring delta waves is 75 uV (peak-to-trough) amplitude, and 0.5 second
duration (2 Hz).
Sleep Study - monitoring of several physiological activities in a sleeping
individual. Usually performed to determine the absence or presence of a
specific sleep disorder. The sleep study can occur in a sleep disorders
center or in a patient's home with portable recording equipment.
- large, concave muscle attached to the rib cage at bottom of the chest
(top of the abdomen). Inhalation occurs when diaphragm contracts. Exhalation
is passive as the muscle relaxes.
- active and wakeful in the daytime versus active in the nighttime
DME - Durable Medical Equipment. Equipment
such as wheelchairs and walkers which are prescribed for use by or on the
order of a physician, also includes CPAP and BI-Level machines.
Drowsy - quiet wakefulness occurring prior to sleep onset.
- a disorder of sleep or wakefulness; not a parasomnia
(EKG) – a method of measuring the electrical activity of the heart.
- small devices transmitting biological electrical activity from subject
(EEG) - recording through the scalp of electrical potentials from the
brain and the changes in these potentials. The EEG is one of the three basic
variables (along with the EOG & EMG) used to score sleep stages and
waking. Surface electrodes are used to record sleep in humans, recording
potential differences between brain regions and a neutral reference point,
or between brain regions.
(EMG) - recording of electrical activity from the muscular system; in
sleep recording, synonymous with resting muscle activity or potential. The
chin EMG, along with EEG and EOG, is one of the three basic variables used
to score sleep stages and waking. Surface electrodes are used to record
sleep in humans, measuring activity from the submental or masseter muscles.
These reflect the changes in resting muscle activity.
During REM sleep the chin/cheek EMG is tonically inhibited.
(EOG) - recording of voltage changes resulting from shifts in position
of the eyeball-possible because each globe is a positive (anterior) and
negative (posterior) dipole; along with the EEG and the EMG, one of the
three basic variables used to score sleep stages and waking. Human sleep
recordings utilize surface electrodes placed near the eyes to record the
movement of the eyeballs. Rapid eye movements in sleep indicate a certain
stage of sleep ( usually REM sleep).
- Ear, Nose and Throat. A doctor
specializing in diseases of the Ear, Nose and Throat. These specialists often do surgery as well, and may be referred
to as an ENT surgeon.
- Expiratory Positive Airway Pressure. Pressure prescribed for the expiratory
(breathing out) phase of an individual on Bi-level CPAP therapy for OSA
(obstructive sleep apnea).
- Scientific discipline studying the incidence, distribution, and control
of disease in a population. Includes the study of factors affecting the
progress of an illness, and, in the case of many chronic diseases, their
- A standard 30 second duration of the sleep recording that is assigned
a sleep stage designation; for special purposes, occasionally longer or
shorter epochs are scored.
Sleepiness Scale - index of sleep propensity during the day as perceived
by patients, and derived from the answers to 8 questions.
Pressure - measurement used to determine respiratory effort and by inference,
airway resistance. Considered an invasive measure, generally used only in
polysomnographic testing, conducted in sleep disorders centers.
daytime sleepiness or somnolence (EDS) - subjective report of difficulty in staying awake, accompanied by
a ready entrance into sleep when the individual is sedentary
Phase - air is expelled during this phase of the breathing cycle
- feeling of tiredness or weariness usually associated with performance
Fiberoptic Nasopharyngoscope - flexible
fiberoptic scope used in the examination of nasal passages, pharynx, hypopharynx
Fibromyalgia - a disease syndrome whose
primary symptoms are muscle pain and fatigue.
Index - number indicating the amount of airflow limitation caused by
partial closure of the upper airway. 0.3 indicates an open airway, 0.15
is mildly obstructed, 0.1 is severely limited airflow, and 0.0 reflects
a totally closed airway. Flattening
Index is used to identify the condition known as Upper Airway Resistance
Syndrome (UARS), and is continuously recorded in both diagnostic sleep studies
and CPAP titrations.
Limitation - the partial closure of the upper airway impeding the flow
of air into the lungs.
Zone - the period of strongest clock-dependent alerting, usually in
the evening. Prevents falling asleep.
Fragmentation (pertaining to Sleep Architecture)
- interruption of a sleep stage as a result of the appearance of a lighter
stage, or to the occurrence of wakefulness, which leads to disrupted non-REM-REM
(Gamma-Amniobutyric Acid) - major neurotransmitter in the brain, which
is considered to be involved in muscle relaxation, sleep, diminished emotional
reaction and sedation.
Reflux Disease (GERD) - flow of stomach acid upwards into the esophagus
that can cause arousals and disrupt sleep.
tongue advancement - a possible surgical treatment used for sleep apnea
and/or snoring, improving the airway behind the base of the tongue. The
genioglossus, the main tongue muscle, relaxes during sleep, often allowing
the tongue to fall into the airway. The muscle attaches to the middle of
the lower jaw. A segment of bone containing this muscle is
pulled forward and stabilized, opening the airway space behind the tongue.
Snorers - those who snore nearly every night
Rate or beats per minute (bpm) - pace/speed of the heart measured in
beats per minute. 60-80 is considered normal in adults.
(Hz) - unit of frequency; equal to cycles per second (cps).
(sleep) - graph indicating sleep stages thoughout the night.
- moisture is added to the airflow as an adjunct to CPAP (Continuous Positive
Airway Pressure) therapy in treating obstructive sleep apnea (OSA). Humidification
can be added to the CPAP by diverting the airflow over or through a cool
or heated water reservoir (humidifier) to prevent the upper airway from
Hyoid Suspension - a possible surgical
procedure sometimes used in the treatment of sleep apnea and/or snoring,
designed to improve the airway behind the base of the tongue. The hyoid
bone is located in the neck where some tongue muscles attach. The hyoid
bone is pulled forward in front of the voice box and can open the airway
space behind the tongue.
Hyperactivity - typical behavior in
a child with a sleep disorder which is causing lack of quality sleep
- excessive or elevated carbon dioxide in the blood
- Extreme irritability; seen in sleep deprived subjects.
- excessive, prolonged sleep
- High blood pressure.
imagery (-hallucinations) - Vivid sensory images occurring at sleep
onset but particularly vivid with sleep-onset REM periods; feature of narcoleptic REM naps.
startle - "sleep start" or sudden body jerk, observed normally
just at sleep onset, resulting in at least momentary awakening
- Morbid fear of falling asleep.
- Sleep-inducing drugs.
- lowermost portion of the pharynx leading to the larynx and esophagus.
- shallow breathing in which the air flow in and out of the airway is less
than half of normal--usually associated with oxygen desaturation.
- reduced rate and depth of breathing.
- abnormal lack of oxygen in the blood in the arteries.
- deficiency of oxygen reaching the tissues of the body.
- New class of compounds inducing sleepiness. (Zolpidem, trade name Ambien,
is in this class).
Sleep Episodes – unplanned sleep periods often occuring in an unsafe
situation (i.e., while driving). These episodes are always due to sleep
- complaint describing difficulty in sleeping
Phase - part of the breathing cycle in which air is inhaled.
- referring to a medical procedure in which a bodily orifice or the skin
must be penetrated for the purpose of collecting data, or for diagnosing
or treating a disorder
- Inspiratory Positive Airway Pressure. Physician prescribed pressure for the inspiratory phase on a Bi-level
CPAP device, used in the treatment of OSA.
Lag - disturbance induced by a major rapid shift in
environmental time during travel to a new time zone
- type of microarousal; K complex
followed by several seconds of alpha rhythm.
complex - sharp, negative, high-voltage EEG wave, followed by a slower,
positive component. K complex, occurring spontaneously during NREM sleep,
beginning in (and defining) stage 2. K
complexes can be elicited during sleep by external (particularly auditory)
stimuli as well.
assisted uvulopalatoplasty (LAUP) - can eliminate or
decrease snoring but has not been shown to be effective in the treatment
of sleep apnea.
Movement - Leg movements are recorded in both diagnostic sleep studies
and titration studies.
of Medical Necessity (LMN) - certification by a physician that the prescribed
item(s) is/are medically indicated, reasonable and necessary with reference
to the standards of medical practice and treatment of a patient's condition
Cycle - periodic pattern of light (artificial or natural) alternating
Sleep - term used to describe non-REM sleep stage 1, and sometimes,
Therapy - used in the treatment of SAD (Seasonal Affective Disorder)
and other conditions. Exposes the eyes to light of appropriate intensity
and duration and at the appropriate time of day to effect the timing, duration
and quality of sleep.
Sleep Disorder - disorder due to child’s difficulty in falling asleep
by delaying and refusing to go to bed
Sleepiness Rating Scale - measure of subjective sleepiness. The scale contains a horizontal line, 100 mm
in length - the right extreme is labeled "Very Sleepy" and the
left extreme is labeled "Very Wide Awake."
- large tongue; usually a congenital disorder (present at birth)
- pertaining to the jaws and face.
Maxillary Osteotomy and Advancement (MMOA) - procedure developed for
patients with retrolingual obstruction, patients with retropalatal and retrolingual
obstruction who have not responded to CPAP and uvulopalatopharyngoplasty
- hormone secreted by the brain’s pineal gland
- partial awakening from sleep
- period lasting up to a few seconds during which the polysomnogram suddenly
shifts from waking characteristics to sleep.
(sleep) apnea - interruption in breathing during sleep beginning as
a central apnea then becoming an obstructive apnea.
- a single major sleep period and a single major wake period in a 24-hour
Activity in Sleep - any muscular movement during sleep
Atonia - the absence of muscle activity during sleep
arousal - body movement associated with arousal or awakening; a sleep
time - term used in sleep record scoring to denote when EEG and EOG
tracings are obscured for more than 15 seconds due to movement.
sleep latency test (MSLT) - a series “nap tests” utilized in the assessment
of excessive daytime sleepiness.
Tone - amount of tension in a muscle.
- muscle contractions in the form of "jerks" or twitches.
- short period of planned sleep generally obtained at a time separate from
the major sleep period.
- sleep disorder characterized by excessive sleepiness, cataplexy, sleep
paralysis, hypnogogic hallucinations, and an abnormal tendency to pass directly
from wakefulness into REM sleep
Airflow/Nasal Ventilation - recording of the complete respiratory cycle
by measuring inspiratory and expiratory airflow
Commission on Sleep Disorders Research (NCSDR) - the commission (created
by the U.S. Congress in 1990) conducted a comprehensive study of the social
and economic impact of sleep disorders in America and made recommendations
based on its findings to the Congress in January 1993
- branch of medicine that referring to the nervous system and its diseases
- endogenuous chemical components that are released from axon terminals
of one neuron and transmit the signal to the next neuron by combining with
its receptor molecules. Neurotransmitters
important in the control of sleep and wakefulness include: norepinephrine,
serotonin, acetylcholine, dopamine, adrenaline and histamine.
- unpleasant and/or frightening dream occurring in REM sleep (different
from a night terror)
Terrors - also known as sleep terrors, or pavor nocturnus. Night terrors are characterized by an incomplete
arousal from slow wave sleep. If,
the individual is awakened during a night terror, he/she is usually confused
and does not remember details of the event. Night terrors are different from nightmares; if an individual is
awakened during a nightmare, he/she functions well and may have some recall
of the nightmare.
- excessive, often frequent, urination during the night
- "Of the night;" pertaining to events happening during sleep
or the hours of darkness.
Nocturnal Confusion - episodes of delirium
and/or disorientation near or during nighttime sleep; often seen in victims
of Alzheimers Disease and more common in the elderly
Nocturnal sleep-related eating disorder
(NS-RED)- Getting up during the night and eating while sleepwalking.
No recall in the morning.
Enuresis (Bedwetting) - urinating while asleep
- Medical procedure not penetrating the skin or a body cavity.
or non-REM sleep - characterized by slower and larger brain waves and
little or no dream behavior; quiet
sleep, slow-wave sleep; approximately
80% of sleep
Sleep Intrusion - brief period of NREM sleep patterns appearing in REM
sleep; a portion of NREM sleep not
appearing in its usual sleep cycle position
Syndrome - term applied to obese individuals hypoventilating during
apnea - cessation of airflow (at least 10 seconds) in the presence of
continued inspiratory effort, cessation
of breathing during sleep, due to a mechanical obstruction, such as a semi-collapsed
trachea, tongue relaxed to back of the throat, or a large among of tissue
in the uvula area.
Hypopnea - periodic and partial closure of the throat during sleep resulting
in reduced air exchange at the level of the mouth and/or nostril.
Curse - the respiratory center in the brain is unable to stimulate breathing
in response to an increased amount of carbon dioxide in the blood. Ondine's Curse or central alveolar hypoventilation
typically worsens during sleep.
Sleep - average amount of sleep needed every night by an individual.
Desaturation - less than normal amount of oxygen carried by hemoglobin
in the blood; values below 90% are
Saturation - measure of oxygen carried by hemoglobin in the blood. Normal
values 90% - 100%.
(Pulse) - gives estimates of arterial oxyhemoglobin saturation (SaO2)
by utilizing selected wavelengths of light to non invasively determine the
saturation of oxyhemoglobin (SpO2)
(Pulse) - continuous monitoring of oxygen saturation of arterial blood
from a pulse oximeter; the sensor
is usually attached to the finger.
- Chemical symbol for oxygen. Criterion lowest percent O2 saturation: Greater
than 85%=mild, 80% to 85%=moderate, less than 80%=severe
- an event happening during sleep, or induced or exacerbated by sleep, such
as sleepwalking or asthma; not a dyssomnia.
nocturnal dyspnea (PND) - respiratory distress and shortness of breath
due to pulmonary edema, appearing suddenly and often awakening the sleeping
Sleep - abnormal sleep patterns.
Nocturnus (Night Terrors) - See Night Terrors.
Disengagement - change in consciousness at the onset of sleep when environmental
stimuli are no longer perceived, and there is no longer any conscious, meaningful
interaction with the environment.
Breathing - repetitive apneic pauses, common in premature infants.
Limb Movement Disorder - also known as periodic leg movements and nocturnal
myoclonus. Characterized by periodic episodes of repetitive and highly stereotyped
limb movements occuring during sleep. The movements are often associated
with a partial arousal or awakening; however, the patient is usually unaware
of the limb movements or frequent sleep disruption. Between the episodes, the legs are still. There
can be marked night-to-night variability in the number of movements or in
the existence of movements.
Insomnia - continuing insomnia responding poorly to treatment.
- area posterior to the nares and the oral cavity; passageway for air from the nasal cavity and/or the mouth to the
lungs via the larynx and the trachea, for food and liquids from the mouth
to the esophagus
advance - movement to a position earlier in the 24 hour sleep - wake
cycle of a period of sleep or wake; for example, a shift of the sleep phase
from 11 p.m. - 7 a.m. to 8 p.m. - 4 a.m.
delay - Phase delay is exactly the opposite of phase advance, i.e.,
a shift later in time.
(Event/Activity) - brain, muscle, or autonomic related event of a brief
and episodic nature occurring in sleep. Usually
occur during REM sleep, such as eye movements and/or muscle twitches
- duration of light in a light/dark cycle.
Syndrome - obesity accompanied by somnolence, lethargy, chronic hypoventilation,
hypoxia, and secondary polycythemia (a condition marked by an abnormal increase
in the number of circulating red blood cells); usually has severe obstructive sleep apnea
Gland - gland in the brain secreting the hormone melatonin.
Index - number of sleep-related periodic leg movements per hour of sleep
that are associated with an EEG arousal
- multiple sleep periods and wake periods in a 24-hour day.
- partial pressure of oxygen (O2) in the blood. A value above 60 is usually
considered a safe level: lower than
60 indicated hypoxemia and potential danger for the patient.
(PSG) - continuous and simultaneous recording of physiological variables
during sleep, i.e., EEG, EOG, EMG (the three basic stage scoring parameters),
EKG, respiratory air flow, respiratory excursion, lower limb movement, and
other electrophysiological variables.
- biomedical instrument for the measurement of multiple physiological variables
Technologist - health care professional trained in performing diagnostic
Drowsiness - sleepiness that occurs after a meal, usually lunch
Stress Disorder - re-experiencing of a traumatic event in the form of
repetitive dreams, recurrent and intrusive daytime recollections, and/or
dissociative flashback episodes.
morning awakening - early termination of the sleep period in a sleep
maintenance DIMS due to inability to return to sleep after the last of several
CPAP Pressure - pressure(s) or settings determined by a CPAP titration
sleep study, which a physician prescribes for a patient's CPAP therapy machine
Oximetry - non-invasive measure of oxygen saturation; that is the amount
of oxygen saturated in the hemoglobin in terms of percentage; not as accurate as the values obtained from
an arterial blood gases (ABG) test and should only be used as a gauge of
oxygenation. Normal ranges are between
Sleep - The term frequently used instead of NREM sleep
to describe the sleep of infants.
(RF) - Electromagnetic radiation in the frequency range 3 kilohertz
(kHz) to 300 gigahertz (GHz); considered to include microwaves and radio
waves. Microwaves occupy the spectral region between
300 GHz and 300 MHz, while RF or radio waves include 300 MHz to 3 kHz.
(RF) Procedure (also known as Somnoplasty) - procedure for treating
nasal obstruction, snoring and in some cases, sleep apnea. The procedure
uses radiowave energy to reduce snoring and the size of the soft palate.
- Respiratory Disturbance Index, includes all respiratory events per hour.
sleep, rapid eye movement sleep - sleep characterized by the active
brain waves, flitting motions of the eyes, and weakness of the muscles;
most dreaming occurs in this stage, which accounts for about 20% of sleep
Density - A function that expresses the frequency of eye movements per
unit of time during REM sleep.
Disorders - Sleep disturbances that occur in REM sleep.
latency - The period of time in the sleep period from sleep onset to
the first appearance of stage REMS.
Motor Atonia - The active suppression of activity in the antigravity
and voluntary muscles during REM sleep. The muscles are completely flaccid
onset - designation for commencement of a REM period; used also as a shorthand term for a sleep-onset REM period
period - 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.
rebound or recovery - lengthening and increase in frequency and density
of REM periods, which results in an increase in REM percent above base line.
REM rebound follows REM deprivation once the inhibitory influence is removed
Sleep Behavior Disorder (RBD)- disorder in which REM motor atonia is
partially or completely absent and the individual acts out the ongoing dream.
The behavior in REM behavior disorder is often correlates with the ongoing,
hallucinatory REM dream episode.
Sleep Episode - REM sleep portion of a NREM-REM sleep cycle. Early in
the first sleep period, episodes may be only several minutes in duration.
Later REM episodes almost are always longer, 20 to 30 minutes up to an hour.
Sleep Intrusion - brief interval of REM sleep appearing out of its usual
positioning in the NREM-REM sleep cycle.
Sleep Latency - interval from sleep onset to the first appearance of
Sleep Onset - designation for the first epoch of a REM sleep episode
Sleep Percent - proportion of total sleep time occupied by REM sleep
Sleep Rebound - compensatory increase in REM sleep following experimental
reduction. Extension of time in, and an increase in frequency and density
of REM sleep episodes; usually an
increase in REM sleep percent of total sleep time above baseline values
Care Practitioner (RCP) - licensed health care professional specifically
trained in cardiopulmonary assessment, diagnostics, therapy administration,
and patient education, including the identification and treatment of sleep
Restless Legs Syndrome (RLS) - sleep
disorder characterized by a deep creeping, or crawling sensation in the
legs that tends to occur when an individual is not moving. There is an almost
irresistible urge to move the legs; the sensations are relieved by movement.
(Referring to Quality of Sleep) - Persistent or recurrent body movements,
arousals, and/or brief awakenings in the course of sleep
- compounds tending to calm, and reduce nervousness or excitement and foster
Situation - not requiring physical activity, e.g. working at a desk,
sitting in a meeting or in a theater, watching television.
- surgery on the nasal septum (dividing the nasal passage)
- neurotransmitter in the brain that modulates mood, appetite, sexual activity,
aggression, body temperature and sleep
- working hours outside of the conventional daytime hours of 9:00 a.m. to
- a state marked by lessened consciousness, lessened movement of the skeletal
muscles, and slowed-down metabolism
Apnea - cessation of breathing for 10 or more seconds during sleep
architecture - NREM/REM stage and cycle infrastructure of sleep understood
from the vantage point of the quantitative relationship of these components
to each other
cycle - synonymous with NREM-REM cycle
Debt - result of recurrent sleep deprivation which occurs over time
when an individual does not experience a sufficient amount of the restorative
daily sleep that is required to maintain a sense of feeling rested and refreshed.
Deprivation - acute or chronic lack of sufficient sleep.
Disorders - broad range of illnesses arising from many causes, including,
dysfunctional sleep mechanisms, abnormalities in physiological functions
during sleep, abnormalities of the biological clock, and sleep disturbances
that are induced by factors extrinsic to the sleep process
efficiency (SE) - proportion of sleep in the period potentially filled
by sleep--ratio of total sleep time to time in bed
Episode - interval of sleep that may be voluntary or involuntary
Extension - extending sleep time by increasing the time in bed
Fragmentation - brief arousals occurring throughout the night, reducing
the total amount of time spent in the deeper levels of sleep.
hygiene - conditions and practices that promote continuous and effective
sleep, including regularity of bedtime and arise time; conforming time spent
in bed to the time necessary for sustained and individually adequate sleep
(i.e., the total sleep time sufficient to avoid sleepiness when awake); restriction of alcohol and caffeine beverages
in the period prior to bedtime; employment
of exercise, nutrition, and environmental factors so that they enhance,
not disturb, restful sleep
Hyperhydrosis - excessive sweating during sleep.
Inertia - feelings of grogginess and/or sleepiness that persist longer
than 10 to 20 minutes after waking up
interruption - breaks in the sleep architecture resulting in arousal
latency - time period measured from "lights out," or bedtime,
to the beginning of sleep
log (-diary) - daily, written record of an individual's sleep-wake pattern
containing such information as time of retiring and arising, time in bed,
estimated total sleep period, number and duration of sleep interruptions,
quality of sleep, daytime naps, use of medications or caffeine beverages,
nature of waking activities, and other data
DIMS or insomnia - disturbance in maintaining sleep once achieved; persistently interrupted sleep without difficulty
Mentation - thoughts, feelings, images, perceptions, hallucinations,
and active dreams taking place during sleep
onset - transition from wake to sleep, normally into NREM stage 1 (but
in certain conditions, such as infancy and narcolepsy, into stage REMS)
Onset Imagery - images and experiences during the moments following
the transition from wake to sleep
Sleep-onset REM period - atypical beginning
of sleep by entrance directly into stage REM
Sleep paralysis - waking and not being
able to move for a short period of time, usually occurs out of REM (dream)
pattern (24 hour sleep-wake pattern) - individual's clock hour schedule
of bedtimes and rise times as well as nap behavior: may also include time
and duration of sleep interruptions
Pills - compounds that have a sedative effect,
used to produce sleepiness
Related Accidents - accidents caused by individuals who were sleep deprived
and who, as a result, had impaired judgment
Restriction - limitation of the number of hours in bed
spindle - episodically appearing, spindle-shaped aggregate of 12-14
Hz waves with a duration of 0.5-1.5 seconds, one of the identifying EEG
phenomena of NREM stage 2 sleep
Stage Demarcation - significant polysomnographic characteristics that
distinguish the boundaries of the sleep stages.
stage NREM - major sleep state
apart from REMS; comprises sleep stages 1-4
stage 1 - a stage of NREM sleep occurring after wake. Its criteria consist
of a low-voltage EEG with slowing to theta frequencies, alpha activity less
than 50%, EEG vertex spikes, and slow rolling eye movements; no sleep spindles,
K-complexes, or REMS. Stage 1 normally
assumes 4-5% of total sleep.
stage 2 - a stage of NREM sleep characterized by sleep spindles and
K complexes against a relatively low-voltage, mixed-frequency EEG background;
high-voltage delta waves may comprise up to 20% of stage 2 epochs; usually
accounts for 45-55% of total sleep time.
stage 3 - a stage of NREM sleep defined by at least 20 and not more
than 50% of the period (30 second epoch) consisting of EEG waves less than
2 Hz and more than 75 uV (high -amplitude delta waves); a "delta"
sleep stage; with stage 4, it constitutes "deep "NREM sleep; appears usually only in the first third of the sleep period; usually
comprises 4-6% of total sleep time.
stage 4 - all statements concerning
NREM stage 3 apply to stage 4 except that high-voltage, slow EEG waves,
cover 50% or more of the record; NREM
stage 4 usually takes up 12-15% of total sleep time.
Somnambulism, sleep terror, and sleep-related enuresis episodes generally
start in stage 4 or during arousals from this stage
Sleep stage REM - the stage of sleep
found in all mammal studies, including man, in which brain activity is extensive,
brain metabolism is increased, and vivid hallucinatory imagery, or dreaming
occurs (in humans). Also called "paradoxical sleep" because,
in the face of this intense excitation of the CNS and presence of spontaneous
rapid eye movements, resting muscle activity is suppressed. The EEG is
a low-voltage, fast-frequency, non alpha record. Stage REMS is usually
20-25% of total sleep time.
structure - similar to sleep architecture.
Sleep structure, in addition to encompassing sleep stage and cycle
relationships, assesses the within-stage qualities of the EEG and other
(somnolence, drowsiness) - difficulty in maintaining the wakeful state so
that the individual falls asleep if not actively kept aroused; not simply a feeling of physical tiredness or
talking - talking in sleep takes place during stage REMS, representing
a motor breakthrough of dream speech, or in the course of transitory arousals
from NREMS and other stages. Full
consciousness is not achieved and no memory of the event remains.
or Sleepwalking - individual subject to somnambulism (one who walks
while sleeping). Sleepwalking typically
occurs in the first third of the night during deep NREM sleep (stages 3
Sleep-wake, 24 hour cycle - the clock
hour relationships of the major sleep and wake phases in the 24 hour cycle:
similar to sleep pattern.
shift (-change, -reversal) – sleep wholly or partially moved to a time
of customary waking activity, and the latter is moved to the habitual sleep
period; common in jet lag and shift work.
Transition Disorder - disorder occuring during the transition from wakefulness
to sleep or from one sleep stage to another;
a form of parasomnia
wave sleep (SWS) - sleep stages 3 and 4
(Smart CPAP) - (Smart [Continuous] Positive Airway Pressure) Medical
device used in the treatment of obstructive sleep apnea providing preset
levels of continuous airflow, and automatically adjusting to keep the breathing
passages open by sensing changes in airway integrity. The air flows from
the device through a tube that connects to a nose or face mask.
- noise produced primarily with inspiratory respiration during sleep owing
to vibration of the soft palate and the pillars of the oropharyngeal inlet. Many snorers have incomplete obstruction of
the upper airway, and may develop obstructive sleep apnea.
Palate - membranous and muscular fold suspended from the posterior margin
of the hard palate and partially separating the oral cavity from the pharynx
Complaints - awareness of pain or problems in the body
- walking while asleep
- inducing sleep; hypnotic, as in a drug
- prolonged drowsiness or sleepiness.
- commercial name for radiofrequency treatment of certain sleep disorders
- causing or tending to cause sleep
REMS - condition in which sleep spindles persist atypically in REMS;
seen in chronic DIMS conditions
Sleepiness Scale (SSS) - 7-point rating scale consisting of seven numbered
statements describing subjective levels of sleepiness/alertness
Sleepiness - feelings of sleepiness
Abuse - excessive use of alcohol or drug;
substances can cause sleep disturbances
syndrome - syndrome defined as a defect in the CNS support system for
waking. The few individuals reported
with subwakefulness syndrome have daytime drowsiness and daytime sleep episodes
that are always composed of NREMS stages 1 or 2. The naps occur repetitively
Infant Death Syndrome (SIDS) - sudden
and unexpected death of an apparently healthy infant, whose death remains
unexplained after the performance of an adequate postmortem investigation. Death usually occurs during sleep. SIDS is a classification that is used to describe
a deceased infant. It is not a disease, nor can it be a diagnosis for a
- chronobiological term used to indicate that two or more rhythms recur
with the same phase relationship. In
an EEG tracing, the term is used to indicate an increased amplitude with
an occasional decreased frequency of the dominant activities.
- scheduling sleep to synchronize with the biological clock
- rapid heart rate, usually defined by a pulse rate of over 100 beats per
- small devices placed near the nostrils or mouth to measure air flow by
sensing temperature changes; expired air is warmer than inspired air.
- regulation of body temperature in mammals.
waves - EEG activity with a frequency of 4-8 Hz
Excursion - thoracic (chest) movement, indicating respiratory effort. Usually measured by the placement of a sensor
band, which includes a strain gauge around the chest. The sensor band records chest wall movement
associated with respirations..
Volume - amount of air that
passes in and out of the lungs in an ordinary breath;
usually expressed in liters
- progressive, stepwise increase in CPAP pressure applied during a polysomnogram
to establish the optimal treatment pressure
- in pharmacology, refers to the reduced responsiveness to a drug's action
as the result of previous continued and/or multiple exposure
(Event/Activity) - brain, muscle, or autonomic events, which are continuous.
Usually refers to continuous activity (e.g. muscle atonia) during
- pair of prominent masses of lymphoid tissue that are located opposite
each other in the throat between the anterior and posterior pillars of the
fauces (the narrow passage from the mouth to the pharynx situated between
the soft palate and the base of the tongue). Composed of lymph follicles
grouped around one or more deep crypts.
- surgical removal of the tonsils
Recording Time - duration of time from sleep onset to final awakening.
I n addition to total sleep time, it is comprised of the time taken up by
wake periods and movement time until wake-up.
sleep period - period of time measured from sleep onset to final awakening.
In addition to total sleep time, it is comprised of the time taken up by
arousals and movement time until wake-up
sleep time (TST) - amount of actual sleep time in a sleep period; equal
to total sleep period less movement and awake time. Total sleep time is the total of all REMS and NREMS in a sleep period.
- surgical procedure to create an opening in the trachea (windpipe) so that
one can breathe
- refers to the opening in the trachea. As a treatment for severe obstructive
sleep apnea, a tube to assist oxygenation and ventilation and/or to overcome
an obstruction in the airway located superiorly.
- device designed to convert energy from one form to another
Arousals - brief awakenings from sleep
Insomnia - difficulty sleeping for only a few nights
Antidepressants - medication for depression.
Most tricyclic antidepressants also reduce REM sleep; also used to control cataplectic attacks, hypnogogic
hallucinations, and sleep paralysis.
(penile) - hardening and expansion of the penis: penile erection. Commonly
referred to as nocturnal penile tumescence (NPT) in sleep recordings.
- small, shelf-like, cartilaginous structures covered by mucous membranes,
which protrude into the nasal airway to help warm, humidify, and cleanse
inhaled air on its way to the lungs.
Zone - slang popular term to describe the waking state of individuals
whose MSLT scores are 5 minutes or less. Such individuals are usually sleep
deprived or suffer from a sleep disorder.
(Body Twitch) - very small body movement such as a local foot or finger
jerk which is not usually associated with an arousal.
CPAP Titration Study - sleep study that is usually performed in the
home, after determining that a patient has a sleep related breathing disorder
such as OSA or Upper Airway Resistance Syndrome, and is likely to benefit
from CPAP therapy.
Sleep Episode - sleep episode that is not planned and may happen during
an activity in which such an episode is hazardous, such as when driving
a car or working with machinery
Airway - part of the respiratory anatomy that includes the nose, nostrils,
sinus passages, septum, turbinates; the
tongue, jaws, hard and soft palate, muscles of the tongue and throat, etc.
Airway Resistance Syndrome (UARS) - part of the spectrum of obstructive
sleep-related breathing disorders in which repetitive increases in resistance
to airflow in the upper airway lead to brief arousals and daytime fatigue. Apneas and hypopneas (see RDI) may be totally
absent. Blood oxygen levels can
be in the normal range.
- small soft structure hanging from the bottom of the soft palate in the
midline above the back of the tongue.
(UPPP) - also abbreviated as UPP or UP3 this operation is performed
on the throat to treat snoring and sleep apnea.
UPPP is an accepted means of surgical treatment has a curative rate
of less than 50%. Scientific evidence
suggests that UPPP works best in retropalatal and combination retropalatal
and retrolingual obstruction
time - total
time that is scored awake in a polysomnogram occurring between sleep onset
and final wake-up
Noise - mixture of sound waves extending over a wide frequency range
that may be used to mask unwanted noise that may interfere with sleep
Addition Test - performance test; numbers
added for one hour. Often included in a battery of tests to measure the
impact of acute or chronic sleep loss.
- effects experienced when a patient stops taking sleeping pills
- environmental time cue that entrains biological rhythms to a specific
periodicity. Known Zeitgebers are
light, melatonin and physical activity.
To be effective, these signals must occur when the biological clock
is in a responsive phase.
AB - Automatic Behavior
AD - Alzheimer's Disease
ADA - Americans with Disabilities Act
ADD - Attention Deficit Disorder
ADHD - Attention Deficit Hyperactivity Disorder
AERMS - ambulatory electrocardiogram-respiration monitoring system
AHI – Apnea/Hypopnea Index
AI – Apnea Index
APAP (Auto-CPAP) - auto-titrating, self-adjusting device
BDZ – Benzodiazepine
Bi-PAP (BPAP) - Trademark name of a Bi-Level cpap machine.
BMI – Body Mass Index
BPM – Beats per minute
C - Cataplexy
CDC - Center for Disease Control
CFIDS - Chronic Fatigue Immune Dysfunction Syndrome
CFS - Chronic Fatigue Syndrome
CHF - Congestive Heart Failure
CNS – Central nervous system
CPAP - Continuous Positive Airway Pressure (a nasal device to relieve obstructed breathing in a sleeping patient)
cps – cycles per second
CSR – Cheyne-Stokes respiration
DIMS – Disorders of Initiating and Maintaining Sleep
DME - Durable Medical Equipment
DOES – Disorders of Excessive Somnolence
DSPS - Delayed Sleep Phase Syndrome
Dx - Diagnosis
EDS - Excessive Daytime Sleepiness
EEG – Electroencephalogram
EH - Essential Hypersomnia
EKG - Electrocardiogram
EMG – Electromyogram
ENT – Ear, nose, and throat
EOG – Electro-oculogram
EPAP - Expiratory Positive Airway Pressure
ENT - Ear, Nose, and Throat
GABA - Gamma-Amniobutyric Acid
GERD – Gastroesophageal Reflux Disease
GHB - Gammahydroxybutyrate (a substance occurring naturally in the brain. To be sold as Xyrem)
HH - Hypnogogic Hallucinations
HLA - Human Leukocyte Antigen
Hz - Hertz (frequency)
Hx - Medical History
IH - Idiopathic Hypersomnia
IPAP - Inspiratory Positive Airway Pressure
IRM - Institute of Respiratory Medicine
ITS - I'm Tired Syndrome
LAUP - Laser assisted uvulopalatoplasty
LMN - Letter of Medical Necessity
LTD - Long Term Disability
LO - Lights Out (beginning of sleep recording)
MAO - Monoamine Oxidase (an enzyme in the brain tissue)
MAOI - Monoamine Oxidase inhibitor (a class of anti-depressant.MHC)
MIRS - mandibular inclined repositioning splint
MRI - Magnetic Resonance Imagry
MHC - Major Histocompatibility Complex
MMOA (MMA) - Mandibular Maxillary Osteotomy and Advancement
MSLT - Multiple Sleep Latency Test
MWT - maintenance of wakefulness test
N – Narcolepsy
NCSDR - National Commission on Sleep Disorders Research
NN - Narcolepsy Network
NMH - Neurally Mediated Hypotension
NPT – Nocturnal Penile Tumescence
NREM – Non-Rapid Eye Movement (sleep)
NS-RED – Nonturnal sleep related eating disorder
OCD - Obsessive Compulsive Disorder
ODI - Oxygen desaturation index
OLP - Online Psych
O2 - Oxygen
OSA - Obstructive sleep apnea
OSAS - Obstructive sleep apnea syndrome
PCP - Primary Care Physician
PET - Positron Emission Tomography
PLMD - Periodic Leg Movement Disorder
PLMS - Periodic Leg Movements of Sleep
PND – Paroxsymal Nocturnal Dyspnea
PO2 - partial pressure of oxygen (O2) in the blood.
PSG - Polysomnogram
PTSD - post traumatic stress disorder
PWC - Persons w/CFIDS
PWN - Person (People) with Narcolepsy
PWON - Person (People) without Narcolepsy
POPWN - Parent of a person w/ Narcolepsy
PS – Paradoxical Sleep
QS – Quiet Sleep
RERA – Respiratory effort-related arousal
RBD – Rem Behavior Disorder
RCP – Respiratory Care Practitioner
RDI – Respiratory Disturbance Index
REM - Rapid Eye Movement (sleep)
REML – REM latency
RF - Radiofrequency
RLS - Restless Leg Syndrome
R/O - Rule out
RSD - Reflex Sympathetic Dystrophy
Rx - Prescription
SA - Sleep apnea
SAD - Seasonal Affective Disorder
SaO2 - % of normal Oxygen level in the blood.
SAS - Sleep Apnea Syndrome
SAHS - Sleep apnea/hypopnoea syndrome
SDB - Sleep disordered breathing
SEGS – Number of REM Segments
SEI – Sleep efficiency index
SEM – Slow Eye Movement
SIDS – Sudden Infant Death Syndrom
SL – Sleep latency
SO – Sleep onset
SOREM - Sleep onset REM
SOPWN - Spouse of a PWN
SP - Sleep Paralysis
SPT – Sleep Period Time
Squib - Use of sensitive, superconductor, Josephson junction detectors to map brain activity
SRBD - Sleep-related breathing disorder
SRRD - Sleep-related respiratory disturbance
SSDB - Social Security Disability Benefits
SSI - Supplemental Security Income
SSRI - Selective Serotonin Reuptake Inhibitor (the family of anti-depressants that include Prozac, Zoloft and Wellbutrin among others).
SSS - Stanford Sleepiness Scale
STD - Short Term Disability *OR* Sexually Transmitted Disease
SWL – Slow wave latency
SWS – Slow wave sleep
SWDS – Sleep-wake schedule disorder
Sz – Schizophrenia
S1-S4 – Sleep Stages 1-4
T&A – Tonsillectomy and adenoidectomy
TB – Body Temperature
TCA – Tricyclic antidepressant
TIB – Time in Bed
TLC – Total Lung Capacity
TMT – Total Movement Time
Trec – Rectal temperature
TRD - Tongue retaining device
TRT - Total recording time
TREM – Total REM Time
TST – Total Sleep Time
TSW – Total Slow Wave Sleep (Stage 3 and 4)
TT – Total Time
TWT – Total Wake Time
Tx - Treatment
UARS – Upper Airway Resistance Syndrome
UPPP - Uvulopalatopharyngoplasty
VPAP - Variable positive airway pressure
WAFA - Wake time after final awakening
WASO - Wake time after sleep onset
XPAP - Any type of positive airway pressure device
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