Kettering Sheet (Abbreviations & Terms)

Epochs are 30 secs each. To obtain minutes, take the # of epochs & divide by 2. 30 epochs is 15 minutes.

• Alpha rhythm (posterior dominant rhythm in adults & older children) - An EEG pattern consisting of trains of sinusoidal 8-13 Hz activity recorded over the occipital region with eye closure & attenuating with eye opening

• Apnea - Cessation of airflow (>/= 90% decrease in apnea sensor excursions compared to baseline) of a minimum duration as defined by adult & pediatric rules. Apneas are classified as obstructive, mixed, or central based on the pattern of respiratory effort

• Asystole - An interruption of cardiac rhythm lasting more than 3 seconds

• Atrial fibrillation - An irregular ventricular rhythm associated with replacement of consistent P waves by rapid electrical oscillations

• Beta rhythm - An EEG consisting 13-30 Hz activity

• Bradycardia (during sleep) - A sustained (> 30 seconds) heart rate less than 40 beats per minute for ages 6 years through adulthood

• Bruxism - Grinding or clenching of the teeth during sleep that is often associated with arousal

• Central hypopnea - A specified reduction lasting at least 10 seconds in adults of the equivalent of 2 breaths in children during which there is no evidence of snoring, increased inspiratory flattening of the nasal pressure of PAP device flow signal compared to baseline breathing, or associated thoracoabdominal paradox

• Cheyne-Stokes breathing - A breathing rhythm with a specified crescendo & decrescendo change in breathing amplitude separating central apneas & hypopneas

• Chronological age - The time since birth expressed in either days, months, or years; also referred to as postnatal or legal age

• Conceptional age (CA) - Gestational age (GA) at birth plus the number of weeks postpartum

• Delta frequency - An EEG rhythm consisting of 0-4 Hz activity

• Derivation - The recorded voltage between two electrodes

• Excessive fragmentary myoclonus - Limb EMG activity of specified frequency & duration often unassociated with visible movement. This PSG finding is not thought to have physiological significance

• Eye blinks - EOG events consisting of conjugate vertical eye movements at a frequency of 0.5-2 Hz present in wakefulness with the eyes open or closed

• Gestational Age (GA) - The time elapsed between the first day of the mother’s last menstrual period & the day of delivery expressed in completed weeks. If the pregnancy was achieved using assisted reproductive technology, GA is calculated by adding 2 weeks to the conceptional age.

• High voltage slow (HVS) - Continuous synchronous symmetrical predominantly high voltage 1-3 Hz delta activity

• Hypnagogic foot tremor - Trains of EMG activity of the lower limb with a specified frequency; not a defined order

• Hypnagogic hypersynchrony - An EEG pattern consisting of paroxysmal runs or bursts of diffuse high amplitude sinusoidal 75 to 350 uV, 3-5 Hz waves which begin abruptly, are usually widely distributed by often maximal over the central, frontal, or frontocentral scalp regions

• Hypnogram - A graphical representation of sleep stages which occur throughout the night

• Hypopnea - A reduction in airflow with minimum amplitude & duration as specified in the hypopnea rules for adults & children. The reduction in airflow must be accompanied by a >/= 3% desaturation or an arousal or a >/= 4% desaturation

• Hypoventilation - A specified period of increased PCO2 of > 50 mm Hg in children or > 55 mm HG in adults, or a rise of PCO2 during sleep of >/= 10 mm Hg that exceeds 50 mm Hg for specified period of time in adults

• K complex - An EEG event consisting of a well delineated negative sharp wave immediately followed by a positive component standing out from the background EEG with a total duration of >/= 0.5 seconds, usually maximal in amplitude over the frontal regions

• Low amplitude, mixed frequency activity - An EEG pattern consisting of low amplitude, predominantly 4-7 Hz activity

• Low chin EMG tone - Baseline EMG activity in the chin derivation no higher than in any other sleep stage & usually at the lowest level of the recording

• Low voltage irregular (LVI) - Continuous low voltage mixed-frequency activity with delta & predominantly theta activity

• Major body movement - Movement & muscle artifact obscuring the EEG for more than half an epoch to the extent that the sleep stag cannot be determined

• Monitoring time (MT) - Total recording time minus periods of artifact & time the patient was awake as determined by actigraphy, body position sensor, respiratory pattern, or patient diary

• Narrow complex tachycardia - A cardiac rhythm lasting a minimum of 3 consecutive beats with QRS duration of < 120 msec & a rate of > 10 per minute

• Nasal pressure transducer - A pressure transducer that measures the pressure inside the nasal orifice using a nasal cannula. The pressure difference across the nasal inlet during breathing is proportional to airflow. The inspiratory waveform of nasal pressure signal exhibits a flattened pattern during airflow limitation provided the signal from the transducer is recorded as a DC signal or as an AC signal with an appropriate low filter setting

• Oxygen Desaturation Index (ODI) - The number of oxygen desaturation * 60 divided by the monitoring time (for HSAT) or total sleep time (for in lab PSG)

• Periodic Breathing - > 3 episodes of central apnea lasting > 3 seconds separated by no more than 20 seconds of normal breathing in children

• Periodic limb movements of sleep - movement of the limbs during sleep occurring with a specified frequency, duration, and amplitude

• Peripheral arterial tone - A measure of pulsatile volume changes at the finger tip that reflects changes in sympathetic tone

• Peripheral arterial tonometry (PAT) - A technique allowing noninvasive moment-to-moment measurement of sympathetic tone using finger plethysmography. Increases in sympathetic tone result in peripheral arterial constriction & reduced blood flow to the digit. The reduced volume at the finger is detected by the probe. The combination of a decrease in PAT signal, a fall in SpO2, & an increase in heart rate is used to detect respiratory failure.

• Positive Airway Pressure (PAP) flow - An airflow signal derived from a pressure transducer built into the PAP device

• Posterior dominant rhythm - An EEG pattern with frequency appropriate to age which is observed over the occipital region during relaxed wakefulness with eyes closed & attenuates with eye opening or attention

• PVDF sensor - Polyvinylidene fluoride (PVDF) film is a fluoropolymer substance that reacts to changes in temperature when used as a thermal airflow sensor & to impedance changes when used as an effort sensor

• PVDFsum - The electrical sum of signals recorded from the thoracic & abdominal PVDF sensors

• Rapid eye movements - Eye movements recorded in the EOG derivations consisting of conjugate, irregular, sharply peaked eye movements with an initial deflection usually lasting < 500 msec. Rapid eye movements may be noted during stage W or stage R

• Reading eye movements - Eye movements recorded in the EOG derivations consisting of trains of conjugate eye movements characterized by an initial slow phase followed by a rapid phase in the opposite direction as the individual reads

• REM sleep behavior disorder - A parasomnia characterized by increasing respiratory effort (esophageal manometry); inspiratory flattening in the nasal pressure or PAP device flow channel; or an increase in the end-tidal PCO2 (children) leading to an arousal from sleep. Respiratory effort related arousals do not meet criteria for hypopnea & have a minimum duration of >/= 10 seconds in adults or the duration of at least two breaths in children

• Respiratory event index (REI) - total number of respiratory events scored * 60 divided by monitoring time (MT)

• Respiratory Inductive Plethysmography (RIP) - A technology that uses alternating current in belts surrounding the thorax & abdomen to generate a signal based on changes in the inductance of belts during breathing. The band inductance depends on the cross-sectional area encircled by the band

• Rhythmic Movement Disorder - Repetitive, stereotyped & rhythmic motor behaviors that occur predominantly during drowsiness or sleep and involve large muscle groups

• RIPflow - The time derivative of the RIPsum signal; excursions in the signal are an estimate of airflow

• RIPsum - The electrical sum of the signals from thoracic & abdominal RIP sensors; excursions in the signal are an estimate of tidal volume

• Sawtooth waves - An EEG pattern consisting of trains of sharply contoured or triangular, often serrated, 2-6 Hz waves maximal in amplitude over the central head regions & often, but not always, preceding a burst of rapid eye movements

• Scanning eye movements - Trains of conjugate eye movements with eyes open consisting of a slow phase followed by a rapid phase in the opposite direction as the infant visually scans the environment or follows objects

• Sleep onset - The start of the first epoch scored as any stage other than W

• Sleep spindle - An EEG event consisting of a train of distinct waves with frequency 11-16 Hz (most commonly 12-14 Hz) with a duration of >/= 0.5 seconds, usually maximal in amplitude over the central regions

• Slow eye movements - EOG events consisting of conjugate, reasonably regular, sinusoidal eye movements with an initial deflection usually lasting > 500 msec. Slow eye movements may be present during drowsy wakefulness or stage N1

• Slow wave activity - Waves measured over the frontal regions with a frequency of 0.5-2 Hz & a peak-to-peak amplitude > 75 uV

• Tachycardia or sinus tachycardia (during sleep) - A sustained (> 30 seconds) sinus heart rate > 90 beats per minute

• Thermal sensor - A thermally sensitive device that detects changes in nasal and/or oral airflow based on changes in temperature; thermal sensors include thermistors, thermocouples, or polyvinylidene fluoride (PVDF) airflow sensors

• Theta rhythm - An EEG rhythm consisting of 4-7 Hz activity

• Trace alternant (TA) - Generally only seen in stage N sleep; characterized by at least 3 alternating runs of bilaterally synchronous high voltage (50-150 uV) burst of 1-3 Hz delta activity lasting 5-6 seconds (range 3-8 seconds) alternating with period of lower amplitude (25-50 uV) 4-7 Hz theta activity (range 4-12 seconds)

• Transient muscle activity - Short irregular burst of EMG activity usually with duration < 0.25 seconds superimposed on low EMG tone. The activity may be seen in the chin or anterior tibial EMG derivation, as well as in EEG or EOG derivations, the latter indicating activity of cranial nerve innervated muscles. The activity is maximal in association with rapid.

• Vertex sharp waves (V waves) - An EEG pattern consisting of sharply contoured waves with duration of < 0.5 seconds maximal over the central region & distinguishable from the background activity

• Wide complex tachycardia - A cardiac rhythm lasting a minimum of 3 consecutive beats with QRS duration >/= 120 msec & a rate of > 100 per minute

Questionnaires/Scales

Epworth Sleepiness Scale

STOP-BANG Questionnaire

AHI & RDI Interpretation (RDI is the same scale)

BMI Scale

MSLT Interpretation