Sleep scoring guidelines santosh

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Sleep scoring guidelines santosh

  1. 1. Sleep scoring guidelines PCCSU Article | 03.03.08 By Teofilo Lee-Chiong, MD, FCCP
  2. 2. Objectives • To understand the levels of evidence used in the development of the new sleep scoring guidelines. • To enumerate the differences between the Rechtschaffen and Kales rules for sleep scoring and the new sleep scoring recommendations of the American Academy of Sleep Medicine. • To identify the recommended and alternative methods of electrode and sensor placements. • To describe the different electroencephalographic, electrooculographic, and electromyographic features of the various sleep stages. • To describe the new scoring rules for arousals, respiratory events, and movement events.
  3. 3. • It has been 4 decades since Allen Rechtschaffen and Anthony Kales1 standardized the method of scoring polysomnographic recordings. • Since then, major innovations in technology have transformed the science and clinical practice of sleep medicine. • Documentation using paper and ink has been replaced by the monitor screen and disc storage, and analog systems of data collection and retrieval have undergone digitization.
  4. 4. • Many researchers and clinicians in the field have proposed a reexploration of the conventional sleep scoring rules in order to integrate the expanding knowledge of basic neurobiology and the advances in contemporary technology. • An ideal sleep scoring system should have, at least, several attributes.
  5. 5. • It must be physiologically relevant and based on true differences in neurophysiology among the various sleep stages, rather than merely a convenient visual recognition of waveforms. • It must take into account the subtle changes in sleep architecture associated with most sleep disorders (eg, insomnia), rather than just sleep-related breathing disorders. • The new rules should use the full potential of computerization of data, including automation of sleep scoring, recognition of disorders that occur during sleep, and integration with other procedures, such as positive airway pressure titration. • It also must allow taxonomic consistency and have minimal negative impact on current research and epidemiologic conclusions.2
  6. 6. Overview of the Sleep Scoring Guidelines • This article describes and summarizes the recommendations of the American Academy of Sleep Medicine (AASM) regarding the scoring of sleep stages, arousals, respiratory events, cardiac events, and movement events.
  7. 7. • The task force adapted an evidence-based process in determining their recommendations, which are classified as standard (based on level 1 evidence or overwhelming level 2 evidence), guideline (based on level 2 evidence or a consensus of level 3 evidence), consensus (less evidence than guideline, for which agreement was reached in a standardized consensus process based on available information) and adjudication (recommendation from the steering committee based on all available information, with insufficient evidence and no consensus agreement)
  8. 8. Electrode and Sensor Placements • Changes from the conventional Rechtschaffen and Kales method of monitoring adult sleep include the addition of frontal EEG leads, placement of the electrooculographic (EOG) electrodes closer to the outer canthus, the addition of more chin electromyographic (EMG) electrodes, the use of thermistors for the detection of apneas, and the use of nasal air pressure for identifying hypopneas.
  9. 9. EEG • The recommended electrode placements for EEG are F4M1, C4M1, and O2M1, with backup electrodes placed to enable monitoring of F3M2, C3M2, and O1M2. • The scoring guideline allows alternative placements, including FzCz, CzOz, and C4M1, with backup electrodes consisting of FpzC3, C3O1, and C3M2. • Electrode placements are based on the International 10-20 system (F: frontal, C: central, O: occipital, M: mastoid; odd numbers: left, even numbers: right, and z: midline). • The addition of frontal leads was based on level 4 evidence and determined by consensus agreement by the visual task force .
  10. 10. EOG • E1M2 and E2M1 placements for EOG leads are recommended, with E1 placed 1 cm below the left outer canthus and E2 placed 1 cm above the right outer canthus. • Alternative EOG placements include E1Fpz and E2Fpz, with E1 situated 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. • Electrode distances may be reduced to 0.5 cm for children. • Placement of the EOG leads closer to the outer canthus was arrived at by consensus based on level 4 evidence.
  11. 11. EMG • The following three chin EMG electrodes are recommended: (a) midline at 1 cm above the inferior edge of the mandible, (b) 2 cm to the right of midline and 2 cm below the inferior edge of the mandible, and (c) 2 cm to the left of midline and 2 cm below the inferior edge of the mandible. • The derivation consists of either of the inferior electrodes (below the mandible) referred to the electrode placed above the mandible, with the other inferior electrode being used as a backup if the initial electrodes fail. • Electrode distances may be reduced to 1 cm for children. No evidence was provided for the additional chin EMG, and the recommendation was based on consensus and adjudication
  12. 12. ECG • A modified lead II, with electrodes placed below the right clavicle and at the left 6th or 7th intercostal space, is recommended for ECG monitoring.
  13. 13. Airflow (Apnea and Hypopneas) • An oronasal thermal sensor is the recommended method for identifying apneas. • The nasal air pressure transducer is considered an acceptable alternative method for detecting apneas. • End tidal Pco2 or summed calibrated inductance plethysmography can be used for children. • The recommended sensor for hypopneas is the nasal air pressure transducer.
  14. 14. • Alternative sensors for the detection of hypopneas include inductance plethysmography or oronasal thermal sensor. • The use of thermistors as the preferred primary airflow sensor for apneas and the use of nasal air pressure as the preferred secondary airflow sensor for apneas were both arrived at by consensus based on limited evidence. • The use of nasal air pressure as the preferred airflow sensor for identifying hypopneas was based on consistent level 1-5 evidence and was considered a standard practice recommendation.
  15. 15. • Respiratory Effort: Esophageal manometry or inductance plethysmography (calibrated or uncalibrated) are recommended for monitoring respiratory effort, with the diaphragmatic or intercostal EMG offered as an alternative sensor. • Blood Oxygen and Ventilation: Pulse oximetry, with a minimum acceptable signal averaging time of 3 s, is recommended to measure blood oxygen levels. • Transcutaneous or end-tidal Pco2 monitoring can be used to detect the presence of alveolar hypoventilation among children.
  16. 16. Scoring Rules for Sleep Stages • Sleep stages are scored in 30-s epochs, with each epoch being assigned a sleep stage comprising the greatest percentage of the epoch. • There are five wake-sleep stages: stage wake (W), stage NREM 1 sleep (N1), stage NREM 2 sleep (N2), stage NREM 3 sleep (N3), and stage REM sleep (R). • Stage N3 incorporates and replaces the Rechtschaffen and Kales stages NREM 3 and NREM 4 sleep. • Changes from the Rechtschaffen and Kales rules for scoring sleep stages also include new recommendations for scoring stage N2 and stage R, as well as the introduction of a new pediatric stage NREM.
  17. 17. Stage W • An epoch is considered stage W if >50% of the epoch has alpha EEG waves over the occipital region during eye closure. • Alpha waves have a frequency of 8 to 13 Hz. • If alpha waves are absent, the presence of conjugate vertical eye blinks; reading eye movements; or voluntary, rapid open-eye movements also defines stage W. • For children at least 2 months postterm, alpha activity is replaced by the dominant posterior rhythm.
  18. 18. Stage N1 • In stage N1, alpha EEG waves (or dominant posterior EEG rhythm in children) are replaced by low-amplitude, mixed- frequency (4 to 7 Hz) waves that occupy >50% of the epoch. • If alpha waves are not readily apparent, the presence of 4 to 7 Hz waves with slowing of background activity by at least 1 Hz compared with stage W, vertex sharp waves, or slow eye movements also can be used to document the start of stage N1. • In children, the development of rhythmic anterior theta activity, hypnagogic hypersynchrony, or diffuse or occipital predominant high-amplitude, 3 to 5 Hz, rhythmic activity also suggests stage N1 sleep.
  19. 19. Stage N2 • Recommendations are provided defining the start, continuation, and termination of stage N2 sleep. • The start of stage N2 is defined by the presence of nonarousal K complexes or sleep spindles during either the first half of the epoch or the last half of the previous epoch, if criteria for stage N3 are absent.
  20. 20. Stage N2 • (≥2 months postterm) are similar to the adult scoring rulesStage N2 continues if low-amplitude, mixed-frequency EEG rhythm is present in epochs that contain, or are preceded by, K complexes or sleep spindles. • Stage N2 ends with an arousal, a major body movement not followed by stage N2, or when sleep transitions to stage W, N1, N3, or R. • Stage N2 scoring rules were arrived at by consensus based on limited evidence. • Stage N2 scoring rules for children.
  21. 21. Stage N3 • An epoch is scored as stage N3 if at least 20% of the epoch is occupied by slow wave EEG activity over the frontal regions. • Slow waves have frequencies of 0.5 to 2 Hz and amplitudes of greater than 75 µV. • Consistent levels 1 and 2 or levels 3 and 4 evidence were used to formulate the stage N3 scoring rules, which were considered consensus and standard practice recommendations.
  22. 22. Stage N3 • Stage N3 scoring rules for children (≥2 months postterm) are similar to the adult scoring rules. • Among children, an additional stage, NREM sleep (N), can be used if K complexes, sleep spindles, and slow waves are absent in all epochs of NREM sleep. • The recommendation for a pediatric stage N was arrived at by consensus based on either no evidence or limited evidence.
  23. 23. Stage R • An epoch is considered stage R if it contains low- amplitude, mixed-frequency EEG activity and low chin EMG tone that is the lowest level in the study or at least no higher than the other sleep stages, and either has rapid eye movements or is preceded by stage R sleep. • It ends by transitioning to stage W, N1, N2, or N3 sleep. Recommendations for stage R sleep scoring are based on consensus with limited evidence. • Stage R scoring rules for children (≥2 months postterm) are similar to the adult scoring rules
  24. 24. Major Body Movements • The presence of movement or muscle artifact that obscures the EEG for >50% of the epoch is considered a major body movement. • An epoch with a major body movement is scored the same stage as the epoch that follows it, except if alpha rhythm is present, or if it is preceded or followed by a stage W epoch, in which case it is scored as stage W.
  25. 25. Other Scoring Rules • Arousals An arousal during NREM sleep consists of an abrupt EEG frequency shift (eg, alpha, theta, or frequencies >16 Hz, but not spindles) lasting at least 3 s and preceded by at least 10 s of stable sleep. A REM arousal is characterized by similar EEG changes but should be accompanied by an increase in chin EMG that is at least 1 s in duration
  26. 26. Respiratory Events • Apnea in adults consists of a decrease in peak thermal sensor amplitude by at least 90% from baseline for a duration of at least 10 s. • It can be scored as either an obstructive, central, or mixed event based on the presence or absence of inspiratory effort throughout the entire period or part thereof. • In patients aged 18 years or younger, an apnea is generally characterized by a fall in signal amplitude by at least 90% lasting at least two missed breaths.
  27. 27. Hypopnea • Among adults is characterized by a reduction in nasal pressure by at least 30% of baseline for a duration of at least 10 s accompanied by an oxygen desaturation ≥4%. • The hypopnea rules were based on consensus or adjudication. • In patients aged 18 years or younger, a hypopnea is defined by a reduction in nasal pressure amplitude of at least 50% compared with baseline, associated with an arousal, awakening, or oxygen desaturation of at least 3%, that lasts for a duration of at least two missed breaths.
  28. 28. Respiratory effort-related arousals • In adults are described as breaths associated with increasing respiratory efforts or flattening of the nasal pressure waveform that lasts for at least 10 s and precedes an arousal. • They do not otherwise meet criteria for either apnea or hypopnea.
  29. 29. RERA • In patients aged 16 years or younger, respiratory effort- related arousals are characterized by either of the following: • 1.a decrease in sensor signal <50% of baseline levels, associated with flattening of the waveform, snoring, increase in end-tidal or transcutaneous Pco2, or visible increase in work of breathing lasting at least two breath cycles when a nasal pressure sensor is used; or 2.a progressive increase in inspiratory effort accompanied by snoring, increase in end-tidal or transcutaneous Pco2, or a visible increase in work of breathing lasting at least two breath cycles when an esophageal pressure sensor is used.
  30. 30. Hypoventilation • Among adults is characterized as an increase in Paco2 of at least 10 mm Hg during sleep compared with supine awake values. • No evidence was provided for this definition of hypoventilation among adults, and the recommended definition was based on consensus. • Hypoventilation in patients aged 18 years or younger is defined by transcutaneous or end-tidal CO2 level >50 mm Hg in more than 25% of total sleep time.
  31. 31. Cheyne Stokes breathing • In adults consists of at least three consecutive cycles of crescendo-decrescendo change in respiration amplitude lasting at least 10 consecutive minutes or having at least five central apneas/hypopneas per hour of sleep. • This definition was not based on any evidence and was a consensus recommendation. • Periodic breathing in patients aged 18 years or younger is characterized by more than three episodes of central apneas with a duration of >3 s, separated by ≤20 s of normal respiration.
  32. 32. Cardiac Events • Definitions of several cardiac arrhythmias are included in the new sleep scoring guidelines. These include asystole (a cardiac pause >3 s); bradycardia (heart rate <40 bpm); sinus tachycardia (heart rate >90 bpm); atrial fibrillation (irregularly irregular rhythm with variable P wave morphology); narrow-complex tachycardia (heart rate >100 bpm with at least three consecutive beats having a QRS duration of <20 ms); and wide-complex tachycardia (heart rate of >100 bpm with at least three consecutive beats having a QRS duration of ≥120 ms).
  33. 33. Movement Events • The AASM manual provides definitions of various movement events that occur during sleep, including alternating leg muscle activation (consensus recommendation), bruxism (standard recommendation), excessive fragmentary myoclonus (consensus recommendation), hypnagogic foot tremor (guideline recommendation), periodic limb movements in sleep, REM sleep behavior disorder, and rhythmic movement disorder.
  34. 34. A Final Word • Science rests upon a standardized classification system. This is true of sleep medicine, as it is for widely diverse disciplines, such as botany, astronomy, and geophysics. • The new sleep scoring rules developed by the AASM are not merely the result of the rapidly expanding knowledge in the discipline of sleep medicine; they will hopefully be the basis for future advances in the field, as well.

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