CPSGT key terms

A simultaneous recording of brain waves, eye movements, muscle tone, breathing, blood oxygen, heart rhythm, and body position during sleep, used to diagnose sleep disorders and to evaluate treatment.

The overall pattern and proportions of sleep stages across a night, including how much time is spent in N1, N2, N3, and REM and how often the person wakes.

The lightest sleep stage, marked by low-amplitude mixed-frequency EEG, slow rolling eye movements, and fading alpha rhythm; it is the transition from wakefulness into sleep.

A sleep stage defined by sleep spindles and K-complexes on EEG without the amount of slow-wave activity required for N3; it makes up the largest share of adult sleep.

Deep sleep, also called slow-wave sleep, defined by high-amplitude, low-frequency delta waves occupying at least 20 percent of a 30-second epoch.

A sleep stage with rapid eye movements, low-amplitude mixed-frequency EEG, and very low chin muscle tone, in which most vivid dreaming occurs and breathing becomes irregular.

A short burst of 11-16 Hz waves lasting at least half a second, seen on EEG mostly in stage N2 and used as a key marker when scoring sleep stages.

A sharply negative-then-positive, high-amplitude EEG wave lasting at least half a second, often triggered by a noise or internal stimulus, that helps define stage N2.

An abrupt shift in EEG frequency lasting at least three seconds during sleep, which may or may not fully wake the person, and is counted when measuring sleep fragmentation.

The time from lights out to the first epoch scored as sleep; a short latency suggests high sleepiness, while a long one suggests difficulty falling asleep.

Total sleep time divided by time in bed, multiplied by 100; a simple measure of how much of the night was actually spent asleep.

The number of apneas plus hypopneas per hour of sleep; it is the main figure used to classify obstructive sleep apnea as mild, moderate, or severe.

Repeated collapse of the upper airway during sleep that reduces or stops airflow despite continued breathing effort, causing arousals and drops in blood oxygen.

A partial reduction in airflow during sleep lasting at least ten seconds that meets scoring criteria, usually a clear fall in airflow with an associated oxygen desaturation or arousal.

The roughly 24-hour internal clock that regulates sleep-wake timing, body temperature, and hormone release, and that can be shifted by light exposure and schedule changes.

Repetitive, stereotyped limb movements, usually leg jerks, that occur in series during sleep and are detected with leg EMG to evaluate periodic limb movement disorder.

A standard map of skull landmarks used to place EEG electrodes at consistent locations so recordings can be compared across technologists, nights, and laboratories.

The electrical resistance where an electrode meets the skin; it must be low enough, commonly under 5 kilohms, to record a clean signal without extra artifact.

Cleaning and gently abrading the skin before applying electrodes to remove oils and dead cells, which lowers impedance and improves signal quality.

A device, often worn on the chest or built into the belts, that records whether the patient lies supine, prone, or on either side, since apnea is often worse on the back.

A cannula at the nostrils that senses airflow through pressure changes during breathing; it is the preferred sensor for detecting and scoring hypopneas.

A sensor placed at the nose and mouth that detects airflow by temperature change, cooler on inspiration and warmer on expiration, and is used mainly to score apneas.

Elastic bands around the chest and abdomen that measure breathing effort by sensing changes in cross-sectional area, helping separate obstructive from central respiratory events.

A finger or ear probe that continuously estimates blood oxygen saturation and pulse rate using light absorption, supplying the desaturation data paired with respiratory events.

A device that delivers a steady flow of pressurized air through a mask to hold the upper airway open during sleep; it is the primary treatment for obstructive sleep apnea.

A short set of instructed movements before lights out, such as eye movements, blinks, jaw clench, leg lifts, and breathing, that confirms each channel works and is correctly labeled.

A fixed 30-second block of polysomnographic data; sleep stages and most events are scored block by block, so timing on a report is given in these units.

The ordered list showing which electrodes are paired and displayed on each channel, defining how signals appear on screen and which channels the scorer reviews.

A setting that removes slow drifting signal below a chosen frequency, reducing sweat and movement sway so faster brain and muscle activity is easier to see.

The setting that controls how much a signal is amplified for display, so waves of expected size fill the channel without being clipped or becoming too small to read.

Any signal on a channel that comes from something other than the source being measured, such as movement, sweat, electrical interference, or a loose electrode.

Electrical noise from building wiring that appears as a thick, fuzzy band on a channel, usually caused by high electrode impedance or a poor connection.

Electrodes placed under the chin that record muscle tone; the level of tone helps separate REM sleep, where it is lowest, from the other stages.

Electrodes placed near the eyes that record eye movements, showing slow rolling movements in stage N1 and rapid movements during REM sleep.

Recording of brain electrical activity from scalp electrodes; the frequency and amplitude patterns seen are used to identify wakefulness and each sleep stage.

A sleep study in which the technologist adjusts positive airway pressure, and sometimes mask type or mode, to find the setting that best controls breathing events during sleep.

A single-night study in which the first portion is diagnostic and, when criteria are met, the remaining portion is used to begin and adjust positive airway pressure treatment.

Written documentation during the study of events, interventions, patient complaints, and equipment changes, forming the record that supports scoring, interpretation, and any later review.

The process of promptly notifying the supervising clinician or on-call staff about dangerous observations, such as severe oxygen desaturation, arrhythmia, or unsafe patient behavior.

Selecting and adjusting a CPAP mask for comfort and minimal leak, then teaching the patient how to put it on, take it off, and clean it at home.