Understanding and Applying the Updated AASM Scoring Rules

Marietta B. Bibbs, BA, RPSGTMorton Plant Mease Healthcare

Clearwater, FL

Presented at FOCUS 2013-Nashville, TN

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Objectives

• Discuss goals of the AASM Scoring Manual development.

• Describe the significance of changing the scoring rules four years ago.

• Review and critique current AASM scoring rules.• Outline changes and discuss implementation of

the AASM scoring rules revisions.

AASM Scoring Rules1

•Implemented 4 years ago to:•Standardize comprehensive PSG recording, scoring, analysis and reporting. •Incorporate age and disease effects on sleep.•Simplify the rules for easier implementation.•Improve interscorer reliability.•Utilize evidence-based or consensus recommendations for rule development.•Simplify rules for REM onset and termination.•Define major body movements and redefine movement time.

GOALS

•Digital analysis•Technical Specifications•Visual Rules•Arousal Rules•Movement Rules•Respiratory Rules

AASM Scoring Rules Updated R & K Rules3 and Implemented Changes in:

Justifications for Revision of R & K Scoring Rules3

•Clarification of amplifer settings for recording parameters was needed.•Rules did not incorporate scoring for arousals, respiratory events, limb movements, ECG and age effects.

•No revision in the scoring rules since 1963.•Rules did not apply to digital recording techniques (paper based ).•Rules were based on research rather than clinical studies.

Justifications for Revision of R & K Scoring Rules3

•The stage assigned to an epoch was dependent on the score of previous epoch.

•Sleep stage changes were not assigned during the time of actual occurrence.

•Scoring accuracy was compromised in the presence of excessive sleep fragmentation.

•Boundary rules were difficult to follow in REM sleep.

Justifications for Revision of R & K Scoring Rules3

•Single EEG derivation limited display of maximal deflection of certain waveforms.

•Difficult to determine sleep latency in non-alpha producers.•Criteria for slow wave sleep was subjective.

Justifications for Revision of AASM Scoring Rules

Need to address many of the “Frequently Asked Questions”, which are addressed and clarified in the AASM Scoring Rule Revision – Version 2.

Need to address areas of controversy:•Permitting alternative bipolar EEG derivations that result in (cancellation effects) decreasing the amplitude in the frontal EEG recording channels.•Recommending EOG derivations that do not display eye movement direction and is less likely to show eye movements that are low in amplitude. •Combining Sleep stages 3 and 4 into N3, especially in pediatric patients.

Controversial Areas in AASM Scoring Rules1 that Needed to be Addressed

•Allowing two different rules (definitions) for hypopnea scoring.•Disallowing scoring of apnea and hypopnea in Stage W.•Permitting scoring of respiratory events in adolescents >13 using adult scoring criteria.•Lack of sufficient evidence for visual scoring rules to warrant recommendations as a standard when only 3 of 29 rules are evidence-based and the rest based on consensus.

Hypopnea Scoring Rules: Why Use Two Rules?

•Improve interscorer reliability:

•The 4% desaturation rule correlates well with :

•High blood pressure

•Decreased cognition

•Motor vehicles accidents related to sleepiness

•Why is this important?

•Variablity in scoring can significantly affect diagnosis

•IRR is affeced by:

•Event duration

•Degree of amplitude reduction

•Oxygen desaturation level

•Presence and duration of arousal accompanying the event.

Recommended Rule: >30% drop from baseline on the nasal pressure channel with a >4% desaturation from pre-event baseline during at least 90% of event duration. 1

Improve interscorer reliability:•IRR improves when scoring hypopneas in adults when scoring with a >50% reduction in airflow and a >3% desaturaiton.

•Evidence shows that more subtle reductions in airflow are more difficult top achieve good inerscorer agreement.

•Recommendations after publication of the manual:

•Alternative rule be used in epidemiological and outcome studies

•Physicians may select either rule for clinical purposes

•In clinical research, both rules could be used for comparison purposes.

Alternative Rule: >50% drop from baseline on the nasal pressure channel with a >3% desaturation from pre-event baseline during at least 90% of event duration. 1

Recommended rule was chosen for CMS reimbursement purposes, but the alternative definition is preferred by most clinicians.

The Revised AASM Scoring Rules

• Released on October 1, 2012 as version 2.0.

• In digital format for easier updates.

• The scoring manual is copyrighted and may not be reproduced or transmitted in any form (mechanical or electronic).

• Accredited sleep centers are required to comply with all the rules, notes and definitions in the manual.

• Accredited sleep centers may use the recommended, acceptable, or optional rule for scoring without risk to accreditation.

• Rules used in the center are left to the discretion of the physician or investigator.

Report parameters to be used in accredited sleep centers (Chapter II)*

Digital and filter specifications (Chapter III) Technical Specifications and scoring rules (Chapters IV-

VIII): Visual Arousal Cardiac Movement Respiratory

• All report parameters are recommended with exception of a few of the Respiratory events and summary statements.

The Scoring Section of the Manual Includes Seven Chapters

Informational Chapters

• Rules Development -Chapter IX• Procedural Notes – Chapter X• Glossary of Terms – chapter XI

Age Specific Chapters

• The visual rules and respiratory rules are separated into Pediatric and Adult rules in order to address age-specific differences in both recording procedures and scoring procedures in these patient groups.

Report Parameters

REPORT PARAMETERS

1. EEG derivations - Recommended2. EOG derivations - Recommended3. Chin EMG derivations – Recommended4. Leg EMG derivations – Recommended5. Airflow signals used – Recommended6. Respiratory effort signals – Recommended7. Oxygen saturation – Recommended8. Body Position – Recommended9. Electrocardiogram –Recommended (added)

Sleep Scoring Data

1.EEG derivations - Recommended2.EOG derivations - Recommended3.Chin EMG derivations – Recommended4.Leg EMG derivations – Recommended5.Airflow signals used – Recommended6.Respiratory effort signals – Recommended7.Oxygen saturation – Recommended8.Body Position – Recommended9.Electrocardiogram –Recommended (added)

General Parameters

REPORT PARAMETERS

Sleep Scoring Data (continued)

Stage R latency: - sleep onset to first epoch of Stage R in minWake after sleep onset: (WASO;TRT-SL-TST, in min)*Percent sleep efficiency (TST / TRT × 100 )Time in each stage (min)Percent of TST in each stage (time in each stage / TST) × 100

*Wake after sleep onset includes all wake activity, including time out of bed. Time with the patient disconnected from the recording equipment should be scored as stage W. Brief episodes of sleep during this time, if they occur, are not considered significant for the stage scoring summary.2

Arousals Events

Number of arousals - Ar (count)Arousal Index - ArI (Ar/sleep hour) Ar X 60 / TST]

Movement Events

Number of periodic limb movements of sleep - PLMS (count)Number of periodic limb movement of sleep with arousal - PLMSAr (count)Periodic limb movement of sleep index – PLMSI (ratio) [PLMSX60/TST] Periodic limb movement of sleep with arousal index - PLMSArI (ratio)

[PLMSArX60/TST]

REPORT PARAMETERS

Average heart rate during sleepHighest heart rate during sleepHighest Heart rate during recording

REPORT PARAMETERS

Cardiac Events

Occurrence of arrhythmia:Bradycardia (yes/no) [list lowest rate]Asystole (yes/no) [list longest pause]Sinus tachycardia (yes/no) [list highest rate]Narrow complex tachycardia (yes/no) [list highest rate]Wide complex tachycardia (yes/no) [list highest rate]Atrial fibrillation (yes/no) Other arrhythmias if present (yes/no) [list type]

Number of obstructive apneasNumber of mixed apneasNumber of central apneasNumber of hypopneasNumber of obstructive hypopneas (optional) (added)Number of central hypopneas (optional) (added)Number of apneas + hypopneas Apnea index (AI; (# obstructive apneas + # central apneas + # mixed apneas) × 60 / TST) Hypopnea index (HI; # hypopneas × 60 / TST) Apnea + Hypopnea index (AHI; # of apneas and hypopneas × 60 / TST)

Optional Parameters

Obstructive apnea hypopnea index (OAHI; (# obstructive apneas + # mixed apneas + # obstructive hypopneas) × 60 / TST) *Central apnea hypopnea index (CAHI; (# central apneas + # central hypopneas) × 60 / TST) *Respiratory effort-related arousals (RERAs, total number)Respiratory effort-related arousal index (RERA index; # of RERAs × 60 / TST)Respiratory disturbance index index (RDI; AHI + RERA index)*Oxygen desaturations ≥3% total number**Oxygen desaturation index ≥3% (ODI; # oxygen desaturations ≥3% × 60 / TST)N1 ***added **removed or >4%

REPORT PARAMETERSRespiratory Events

Arterial oxygen saturation, mean value * Minimum oxygen saturation during sleep Occurrence of hypoventilation during diagnostic study *

Adults (optional) *Children *

Occurrence of hypoventilation during PAP titration (in adults and children) (optional)*Occurrence of Cheyne-Stokes breathing in adultsDuration of Cheyne-Stokes breathing (absolute or as a percentage of total sleep time) or the number of Cheyne-Stokes breathing events.Occurrence of periodic breathing in childrenOccurrence of snoring*added

REPORT PARAMETERSRespiratory Events

Important Notes: If measuring arterial PCO2 or surrogate during sleep in cases where it is optional to do so, the occurrence/absence of hypoventilation must be included in the PSG report.2

Reporting the occurrence of Cheyne-Stokes breathing in the PSG report is required only if central apneas are present. 2

Digital Specifications Filter Settings

•Electrode impedances remain at a maximum recommendation of 5 KΩ.•Minimum digital resolution remains the same at 12 bits per sample.•No change to sampling rates for all recording parameters (EEG, EOG, EMG, ECG, airflow, oximetry, nasal pressure , esophageal pressure, body position, snoring or respiratory effort).

•Added digital specifications for Transcutaneous PCO2, End-Tidal PCO2, esophageal pressure and PFlow.

•All digitial specifications and filter settings are recommended. No alternatives or options provided.

YANG•No change in recommended filter settings for EEG, EOG, EMG, ECG, Respiration and Snoring.•Expanded respiration to specify filter settings relate to thermal flow and respiratory effort belts.•Added filter settings for Nasal Pressure and PAP device flow.

•Notes are more comprehensive in explaining the filter settings and digitial specifications.

Recommended Sampling Rates

Parameter Desirable Minimal

EEG 500 Hz 200 Hz

EOG 500 Hz 200 Hz

EMG 500 Hz 200 Hz

ECG 500 Hz 200 Hz

AIRFLOW 100 Hz 25 Hz

Parameter Desirable Minimal

SaO2, TcPO2 25 Hz 10 Hz

Nasal Pressure, End-Tidal PCO2, PFlow

100 Hz 25 Hz

Esophageal Pressure 100 Hz 25 Hz

Body Position 1 Hz 1 Hz

Snoring 500 Hz 200 Hz

Respiratory Effort 100 Hz 25 Hz

Filter Settings

Low Frequency High Frequency

EEG 0.3 Hz 35 HzEOG 0.3 Hz 35 HzEMG 10 Hz 100 HzECG 0.3 Hz 70 HzFlow and Effort 0.1 Hz 15 HzSnoring 10 Hz 100 HzNasal Pressure DC or 0.03 Hz 100 HzPflow DC DC

The rule: filter settings should simulate or replicate conventional analog filter frequency response curves.

Older equipment high frequency filter settings can be 30-35 Hz

PSG Recording Features, PSG Display and Display Manipulation and Digital Analysis of PSG

PSG Recording Features•No changes noted in this section of the manual.•All are Recommended with exception of a electrode selector panel which would allow changing electrode derivations without using a common reference.

PSG Display and Display Manipulation•Virtually unchanged with the same recommendations and optional features•Clarified information regarding display resolution for scoring and reviewing data. Screen must meet or exceed 15 inch screen size, 1600 pixels horizontal and 1050 pixels vertical.

Digital Analysis of PSGRequirements for PSG recording systems unchanged with the same recommended features and optional features.

Visual Rules for Adults

Technical Specifications for EEG Derivations

RecommendedF4-M1

C4-M1

O2-M1

BackupF3-M2

C3-M2

O1-M2

Acceptable

FZ-CZ

CZ-OZ

C4-M1

Backup FPZ, C3, O1, M2

For FZ CZ/C4 O2 M1

No change in recommendations

The International 10-20 System is used to determine electrode

placement.

Special Considerations• The manual notes that the Fz-Cz derivation used in the acceptable

montage is not appropriate for scoring Stage N3 due to the fact that this derivation produces cancellation effects when N3 slow wave activity or K-complexes are of similar amplitude over the frontal and central regions.

• If the recommended EEG derivations are used, slow wave activity should be measured from F4-M1. The C4-M1 derivation can also be used to measure slow wave activity when using the recommended EOG derivations and the acceptable EEG derivations, but this does not resolve the problem with the frontal derivations.

• If the acceptable EEG and EOG montage derivations are used, the E1-FPz derivation is recommended since FPz would become the active electrode.

EOG Technical Specifications

Recommended Derivations and placements: E1-M2 and E2-M2

E1 (active electrode) is placed 1 cm below the left outer canthus E2 (active electrode) is placed 1 cm above the right outer canthus

1 cm

1 cm

Right = E2 Left = E1

The recommended derivation does not display eye movement direction and is less likely to show eye movements that are low in amplitude; however, artifacts are more easily seen.

No Change

EOG Technical Specifications

Acceptable EOG Derivations and placements: E1-Fpz & E2 – Fpz

E1 placed 1 cm below and 1 cm lateral to the left outer canthus, and E2 placed 1 cm below and 1 cm lateral to the right outer canthus

Right = E2 Left = E1

1 cm 1 cm1 cm1 cm 1 cm

The acceptable placement shows the direction of eye movements. Moving the eyes to the left and right (horizontal) will result in out-of-phase deflections, and moving the eyes up and down (vertical) will produce in-phase deflections.

No Change

Recommended vs Alternative EOG Derivation

RECOMMENDED EOG ACCEPTABLE EOG

E1-M2 E2 (1 cm above)

E2-M2 ↑

↓ E1 (1 cm below)

E1-FPzE2-FPz

E2 E1

Does not show direction of eye movements

Does show direction of eye movements

Can miss low amplitude eye movements Shows all eye movements

Easy to distinguish artifacts and EEG Less easy to distinguish artifacts

EMG Technical Specifications

Three recording electrodes recommended:

One electrode at midline: 1 cm above the inferior edge of the mandible

Two electrodes placed 2 cm below the inferior edge of the mandible with one electrode 2 cm right and the other placed 2 cm left of the midline.

Derivation: Reference one inferior electrode to the midline electrode and use second electrode as backup.

No Change

Sleep Stage Scoring

Stage W (Wakefulness) Stage N1 (NREM 1)Stage N2 (NREM 2)Stage N3 (NREM 3)Stage R (REM)

No Change to Stage Terminology

Score in 30-second epochs and assign a sleep stage to each epoch.

If two or more sleep stages appear in one epoch, assign the score to the stage comprising the majority of the epoch.

Notable that manual does not show any examples of sleep stages under the descriptions

Stage W•Previous recommendations are the same.•Added Slow eye movements (SEM) defined as “conjugate, reasonably regular, sinusoidal eye movements with an initial deflection usually lasting >500 msec.” •SEMs may be due to electrophysiological and physiological indications of drowsiness during Stage W that may continue into Stage N1.

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SEMS in Stage W

Stage N1

• No change in definitions or rules• Definitions still include:

Slow eye movements Low amplitude, mixed frequency EEG Vertex sharp waves Sleep onset defined as the first epoch scored as any stage of

sleep. Rules are the same

Stage N1

Stage N2

• No change in definitions• No change in starting or continuing stage N2• No change in ending stage N2• No change related to major body movements

occurring in N2

Stage N2

Stage N2

Stage N3

• No change in Definitions or Rules.• One note added explaining that K complexes are

considered to be slow waves if they meet the definition of slow wave activity.

Stage N3

Stage N3

Using the Acceptable Montage

Stage R

• No change in definitions• Scoring still includes presence of rapid eye

movements, low chin EMG, sawtooth waves, and transient muscle activity, low amplitude, mixed frequency.

• No change in rules for continuation of Stage R: Low amplitude, mixed frequency EEG without

presence of K complexes or spindles Low chin tone through the majority of the epoch

Stage R

Stage R

Stage R using the acceptable montage derivations

Ending Stage R

• Rules are the same for ending Stage R

• End Stage R if: There is transition to Stage W or N3; The chin EMG increases above the Stage R level; Criteria for Stage N1 are met; An arousal occurs and is followed by low amplitude, mixed

frequency EEG and slow eye movements (transition to Stage N1);

If a REM EEG remains following an arousal, chin tone remains low, and there are no slow eye movements following arousal, keep in stage R.

End of Stage R

End of Stage R due to arousal followed by low amplitude, mixed frequency EEG and slow eye movements

Scoring Transition Between Stage N2 and Stage R

• No change in transition scoring rules between Stage N2 and Stage R.

• Between definite Stage N2 and definite Stage R, when there is a drop in the chin EMG in the first half of the next epoch to the Stage R level, score the epoch as Stage R even if there are no REMS if all the following epochs meet the Stage R criteria (absence of non-arousal K complex and absence of sleep spindles).

• Between epochs of definite stage N2 and definite Stage R, when there is a drop in the chin EMG in the first half of the epoch to stage R level, score the epoch as Stage N2 if there is presence of non-arousal associated K complexes or spindles and if there is absence of rapid eye movements.

•

Scoring Transition Between Stage N2 and Stage R

• No change in transition scoring rules between Stage N2 and Stage R.

• Between epochs of definite stage N2 with minimal chin EMG tone and definite stage R without further drop in chin EMG tone, score epochs as stage R even in the absence of rapid eye movements, if there is absence of non-arousal associated K complexes and absence of sleep spindles.

• There are no specific rules related to transitions between stage N1 and stage R. Begin Stage R only when rapid eye movements are seen in association with low muscle tone and the typical REM EEG.

Transition epoch between N2 and Stage R

Scoring Major Body Movements• No change in scoring criteria:

• Definition: Major body movement is an epoch in which movement and muscle artifact obscures the EEG for more than half the epoch to the extent that the sleep stage cannot be determined.

• If alpha is present in the epoch, even if it is less than 15 seconds, the epoch should be scored as Stage W.

• If no alpha rhythm is seen in the epoch, but the preceding or succeeding epoch can be scored as stage W, then the major body movement epoch should be scored as stage W.

• If the epoch cannot be scored as stage W, then it should be scored the same as the epoch that follows the major body movement.

Major Body Movement

Epoch is scored as N2 since N2 follows the epoch

Visual Rules for Children

• No change in age description• Rules can be used to score sleep and wake in children

2 months post-term

• No change in terminology for staging• Technical specifications remain the

same as adult • Notes related to the need to reduce the distance for EOG and

chin EMG electrodes in children and infants with small heads

• Change in notes related to when sleep spindles may be seen in children and added a description of how spindles occur during this age.

• “ Sleep spindles may be seen by age 4-6 weeks post-term and are present in all normal infants by age 2-3 months post-term. At this age the spindles are asynchronous between the hemispheres but become more synchronous over the first year of life.2”

Pediatric Scoring Rules Scenarios are Unchanged

If all epochs of NREM sleep contain no recognizable sleep spindles, K complexes or high-amplitude 0.5-2 Hz slow wave activity, score all epochs of NREM sleep as stage N (NREM). 2

If some epochs of NREM sleep contain sleep spindles or K complexes, score those as stage N2 (NREM 2). If in the remaining NREM epochs, there is no slow wave activity comprising more than 20% of the duration of epochs, score as stage N (NREM). 2

If some epochs of NREM sleep contain greater than 20% slow wave activity, score these as stage N3 (NREM 3). If in the remaining NREM epochs, there are no K complexes or spindles then score as stage N (NREM). 2

If NREM is sufficiently developed that some epochs contain sleep spindles or K complexes and other epochs contain sufficient amounts of slow wave activity, then score NREM sleep in this infant as either stage N1, N2 or N3 as in an older child or adult. 2

STAGE W in Pediatrics

The term "posterior dominant rhythm" replaces the term "alpha rhythm" when scoring wakefulness and NREM stages in children.

Epochs are scored as stage W when more than 50% of the epoch has either reactive alpha or age-appropriate posterior dominant rhythm over the occipital region.

Epochs with no discernible reactive alpha or no age-appropriate posterior dominant rhythm should be scored as stage W if ANY of the following are present:

Eye blinks at a frequency of 0.5-2 HzReading eye movementsIrregular, conjugate rapid eye movements associated with normal or high chin muscle tone

Definitions for scoring Stage W are unchanged and include:1.Alpha Rhythm2.Eye Blinks3.Reading Eye Movements4.Rapid Eye Movements5.Dominant Posterior Rhythm

Stage N1 in Pediatrics

Definitions for scoring Stage W are unchanged and include:

Slow eye movementsLow-amplitude, mixed-frequency activityVertex sharp wavesSleep onsetRhythmic anterior theta activityHypnagogic hypersynchrony

If posterior dominant rhythm is present and attenuated or replaced by low-amplitude, mixed-frequency activity >50% of the epoch , score the epoch as stage N1. If the posterior dominant rhythm, is not present score stage N1 when any of the following occur:

Activity in the range of 4-7 Hz with slowing of background frequencies by ≥1-2 Hz from those of stage W Slow eye movements Vertex sharp waves Rhythmic anterior theta activity Hypnagogic hypersynchrony Diffuse or occipital-predominant, high-amplitude, rhythmic 3-5 Hz activity2

STAGE N2 AND STAGE N3 IN PEDIATRICS

Score stages N2 and N3 in children utilizing the same rules as adults

STAGE R IN PEDIATRICS

Score stage R in children utilizing the same rules as adults

The continuous, low-amplitude, mixed-frequency EEG activity of stage R in infants and children resembles adults although the dominant frequencies increase with age: approximately 3 Hz activity at 7 weeks post-term, 4-5 Hz activity with bursts of sawtooth waves at 5 months, 4-6 Hz at 9 months, and prolonged runs or bursts of notched 5-7 Hz theta activity at 1-5 years of age may populate the background activity. By 5-10 years of age, the low-amplitude, mixed-frequency activity in stage R is similar to that of adults.2

Arousal RulesNo changes in arousal scoring

Score arousal during sleep stages N1, N2, N3, or R if there is an abrupt shift of EEG frequency including alpha, theta and/or frequencies greater than 16 Hz (but not spindles) that lasts at least 3 seconds, with at least 10 seconds of stable sleep preceding the change. Scoring of arousal during REM requires a concurrent increase in submental EMG lasting at least 1 second.2

The new rules include an additional note for clarification of arousal scoring during Stage W.

Arousals meeting all scoring criteria but occurring during an awake epoch in the recorded time between "lights out" and "lights on" should be scored and used for computation of the arousal index2

CARDIAC RULES

No change in technical specifications or lead placements

No change in scoring cardiac eventssinus tachycardia bradycardiaasystolewide complex tachycardia narrow complex tachycardia atrial fibrillation

One note added to address sustained sinus braydcardia or tachycardia:Sustained sinus bradycardia or tachycardia is defined by more than 30 seconds of a stable rhythm to distinguish it from transient responses, associated sleep disordered breathing events or arousals. 2

Movement Rules

Periodic Limb MovementsNo change in the definition, duration, amplitude, onset or ending, or PLM series.

PLM SeriesFour consecutive LM events define a PLM series.The minimum time between onsets of consecutive LMS to include them as part of a PLM series is 5 seconds.The maximum time between onsets of consecutive LMs to include them as part of a PLM series is 90 sec.Leg movements on 2 different legs separated by less than 5 seconds between movement onsets are counted as a single leg movement.2

A significant leg movement has a minimum duration of 0.5 seconds with a maximum duration of 10 seconds and a minimum 8V increase in voltage amplitude above resting EMG.The onset of a LM is the point where there is an 8V voltage increase in amplitude above the resting EMG.The LM event ends at the point when at least 0.5 seconds of the EMG does not exceed 2V above resting EMG.2

Other Movements

• No change in definition or rules related to:•Alternating Limb Movements•Hypnagogic Foot Tremor•Excessive Fragmentary Myoclonus•Bruxism

Scoring Features of REM Sleep Behavior Disorder

The polysomnographic characteristics of RBD are characterized by EITHER or BOTH of the following features:

a. Sustained muscle activity in REM sleep in the chin EMG.b. Excessive transient muscle activity during REM in the chin or limb EMG.2

No Change in Definitions: Includes:

Sustained (tonic) muscle activity in REM SleepExcessive transient muscle activity (phasic activity) in REM sleep

No change in definitions, mininum or maximum frequencies or amplitudes

Scoring feature of Rhythmic Movement Disorder

Excessive transient muscle activity (phasic) during REM sleep in the limb EMG

Respiratory Rules for Adults

To score hypopnea during a diagnostic study, a nasal pressure transducer (with or without square root transformation of the signal) should be used to monitor airflow.

If the nasal pressure transducer is not functioning or the signal is not reliable for identification of a hypopnea during a diagnostic study . use one of the following (alternative hypopnea sensors): 2

a. oronasal thermal airflow b. RIPsum (calibrated or uncalibrated) c. RIPflow (calibrated or uncalibrated) d. dual thoracoabdominal RIP belts (calibrated or uncalibrated) e. PVDFsum 2

Technical Considerations

To score an apnea during a diagnostic study, an oronasal thermal airflow sensor should be used to monitor airflow. In the event that the oronasal thermal airflow sensor is not functioning or the signal is not reliable during a diagnostic study, use one of the alternative apnea sensors: 2

a. nasal pressure transducer (with or without square root transformation) b. RIPsum (calibrated or uncalibrated) c. RIPflow (calibrated or uncalibrated) d. PVDFsum 2 (acceptable)

More Alternative Sensors Options

Technical ConsiderationsThe PAP device flow signal output should be used to identify apnea and hypopnea during positive airway pressure (PAP) titration.

For monitoring respiratory effort, use one of the following:

a. esophageal manometry b. dual thoracoabdominal RIP belts (calibrated or uncalibrated) c. dual thoracoabdominal PVDF belts (acceptable)

Oxygen saturation should be monitored with pulse oximetry with a maximum acceptable signal averaging time of ≤3 seconds at a heart rate of 80 beats per minute.

The monitoring of snoring g is optional. If snoring is monitored, use an acoustic sensor (e.g. microphone), piezoelectric sensor or nasal pressure transducer. Detection of hypoventilation during a diagnostic study is accomplished by using arterial PCO2, transcutaneous PCO2 or end-tidal PCO2.

During PAP titration, detection of hypoventilation is accomplished by using arterial PCO2, or transcutaneous PCO2.

No change in event duration rules

Apnea or hypopnea event is measured from the nadir preceding the first breath that is clearly reduced to the beginning of the first breath that approximates the baseline breathing amplitude.

Terminate events when there is clear and sustained increase in breathing amplitude or where a desaturation has occurred, there is event resaturation of at least 2%.

Added a rule for scoring event duration:

For apnea duration, the oronasal thermal sensor signal (diagnostic study) or PAP device flow signal (PAP titration study) should be used to determine the event duration. For hypopnea event duration, the nasal pressure signal (diagnostic study) or PAP device flow signal (PAP titration study) should be utilized. When the diagnostic study sensors fail or are inaccurate, alternative sensors may be used.2

Nadir precedingNadir preceding 11stst reduced breath reduced breath

Beginning of first breathBeginning of first breathApproximating baselineApproximating baseline

Beginning of event is nadir preceding the first breath of eventEnd of event is beginning of first breath that approximates baseline (not defined).

Scoring of Apneas

No change in apnea scoring as far as event duraion, amplitude reduction or event classification.

Removed 90% of event duration must meet amplitude reduction criteria.

There is not sufficient evidence to support a specific duration of the central and obstructive components of a mixed apnea; thus, specific durations of these components are not recommended

If a portion of a respiratory event that would otherwise meet criteria for a hypopnea meets criteria for apnea, the entire event should be scored as an apnea.2

Significant clarification notes have been added:

Scoring Apneas

• Notes Added • If the apnea or hypopnea event begins or ends during an epoch that is scored as sleep,

then the corresponding respiratory event can be scored and included in the computation of the apnea hypopnea index (AHI).

• This situation usually occurs when an individual has a high AHI with events occurring so frequently that sleep is severely disrupted and epochs may end up being scored as wake even though <15 seconds of sleep is present during the epoch containing that portion of the respiratory event.

• However, if the apnea or hypopnea occurs entirely during an epoch scored as wake, it should not be scored or counted towards the apnea hypopnea index because of the difficulty of defining a denominator in this situation.

• If these occurrences are a prominent feature of the polysomnogram and/or interfere with sleep onset, their presence should be mentioned in the narrative summary of the study.

Obstructive Apnea

10 Seconds

ParadoxicalParadoxical motionmotion

Absent AirflowAbsent Airflow

Thermal

Pressure

Snore

SpO2

RIP Sum

RIP RC

RIP ABD

10 Seconds

RIP Sum

RIP RC

RIP ABD

SpO2

Snore

Pressure

10 seconds

10 seconds

Thermal

Pressure

Snore

SpO2

RIP Sum

RIP RC

RIP ABD

Sleep onset Central Apnea

10 SecondsAbsent AirflowAbsent Airflow

Absent EffortAbsent Effort

Thermal

Pressure

Snore10 seconds

SpO2

RIP Sum

RIP ABD

RIP RC

10 Seconds

CentralCentral ObstructiveObstructive

Mixed Apnea

Hypopnea Scoring

• Most significant changes in the scoring rules.• Recommended rule changed.• No acceptable rule is noted.• Removed the 90% of event duration must meet

amplitude reduction criteria.• Added definitions for scoring obstructive and

central hypopnea.• Noted that it is optional to score hypopneas as

central or obstructive.

Hypopnea Scoring• Recommended Rule:2

• Score a respiratory event as a hypopnea if ALL of the following criteria are met:

• a. The peak signal excursions drop by ≥30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative hypopnea sensor (diagnostic study).

• b. The duration of the ≥30% drop in signal excursion is ≥10 seconds.

• c. There is a ≥3% oxygen desaturation from pre-event baseline or the event is associated with an arousal.

Definition of Obstructive & Central Hypopnea

• Score a hypopnea as obstructive if ANY of the following criteria are met:

• a. Snoring during the event• b. Increased inspiratory

flattening of the nasal pressure or PAP device flow signal compared to baseline breathing

• c. Associated thoracoabdominal paradox occurs during the event but not during pre-event breathing.

• Score a hypopnea as central if NONE of the following criteria are met:

• a. Snoring during the event• b. Increased inspiratory

flattening of the nasal pressure or PAP device flow signal compared to baseline breathing

• c. Associated thoracoabdominal paradox occurs during the event but not during pre-event breathing.

Hypopnea

10 Seconds

ReducedReduced AirflowAirflow

SnoringSnoring

Desaturation >= 4%Desaturation >= 4%

Phase ShiftPhase Shift

Thermal

Pressure

Snore10 seconds

SpO2

RIP Sum

RIP ABD

RIP RC

Scoring Respiratory Effort Related Arousal

• No change in rules for scoring respiratory effort-related arousal (RERA) except adding the technical specifications for recording devices used during diagnostic and PAP studies.

Scoring Hypoventilation

• Language clarified for scoring hypoventilation during sleep:

Score a respiratory event as hypoventilation during sleep if EITHER of the below occur:

• a. There is an increase in the arterial PCO2 (or surrogate) to a value >55 mmHg for ≥10 minutes.

• b. There is ≥10 mmHg increase in arterial PCO2 (or surrogate) during sleep (in comparison to an awake supine value) to a value exceeding 50 mmHg for ≥10 minutes.2

Scoring Cheyne Stokes Breathing

• Rule has been updated and language changed:• Score a respiratory event as Cheyne-Stokes breathing if

BOTH of the following are met: • There are episodes of ≥3 consecutive central apneas

and/or central hypopneas separated by a crescendo and decrescendo change in breathing amplitude with a cycle length of ≥40 seconds.

• There are ≥5 central apneas and/or central hypopneas per hour of sleep associated with the crescendo/decrescendo breathing pattern recorded over ≥2 hours of monitoring.2

10 Seconds

Cheyne Stokes Breathing

Crescendo- Decrescendo patternCrescendo- Decrescendo pattern

RESPIRATORY RULES IN CHILDREN

Rules expanded to Include:

1.Ages for which Pediatric Scoring Rules Apply.2.Technical Specifications3.Measuring Event Duration4.Scoring of Apneas5.Scoring of Hypopneas6.Scoring Respiratory Effort-Related Arousal7.Scoring Hypoventilation8.Scoring of Periodic Breathing

• Applicable Age:• Rules can be used for

children <18 years, but an individual sleep specialist can choose to score children ≥13 years using adult criteria.

• Technical Specifications:• Same as adult

• Event Duration:• Same as adult

RESPIRATORY RULES IN CHILDREN

• Apnea Rules• No change in event

duration, amplitude missed breaths or event definitions (central, mixed or obstructive).

• Hypopnea Rules:• Same as adult scoring

using the recommended rule and adding drop in signal excursion lasts for ≥2 breaths.

• Event Duration:• Same as adult

RESPIRATORY RULES IN CHILDREN

• No significant change in rules for scoring Respiratory Effort-Related Arousal, Hypoventilation and Periodic Breathing in children.

RESPIRATORY RULES IN CHILDREN

References

1. Iber C, Ancoli-Israel S, Chesson A, and Quan SF for the American Academy of Sleep Medicine. The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications, 1st. Ed.: Westchester, Illinois: American Academy of Sleep Medicine, 2007.

2. Berry RB, Brooks R, Gamaldo CE, Harding SM, Marcus CL, Vaughn BV and Tangredi MM for the American Academy of Sleep Medicine. The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications, Version 2.0. www.aasmnet.org, Darien, Illinois: American Academy of Sleep Medicine, 2012.

3. Rechtschaffen A, Kales A, eds. A manual of standardized terminology, techniques and scoring system for sleep stages of human subjects. Los Angeles, CA: BI/BR, 1968.