SLEEP STAGE SCORING Essentials of Sleep Technology Sleep Stage Scoring Objectives 1. To become familiar with standard terminology, techniques and the scoring system for sleep stages. 2. To develop visual recognition skills in determining sleep stages, using R&K criteria. Essentials of Sleep Technology History of Staging Sleep • Late 1920’s Berger (“alpha”, EEG changes with sleep) • 1937; Loomis et al classified 5 stages of sleep (Stage A – Stage E) • 1950; Gibbs and Gibbs (vertex waves, “very light sleep, very deep sleep, early morning sleep”) • 1957; Dement and Kleitman (Stages 1‐4, REM) • 1967 ‐ Formation of Ad Hoc committee ‐ Rechtschaffen and Kales, Co‐Chairs • 1968 ‐ Publication of A Manual of Standarized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects. (R & K Manual) • 2007 – AASM Manual for the Scoring of Sleep and Associated Events • Version 2.1 Essentials of Sleep Technology Staging Sleep by Epochs • 30 second epoch recommended • Some epochs scored in isolation, many will depend on activity in preceding and following epochs • Each epoch assigned a single sleep stage score • Where more than one stage is present in an epoch, the stage that takes up the majority of the epoch is selected Essentials of Sleep Technology Parameters for Staging Sleep • EEG ‐ central EEG lead and occipital EEG lead; frontal lead is now recommended • EOG ‐ left eye and right eye • E1‐M2 • E2‐M2 • EMG – “submental” • 1 cm above inferior edge of mandible • 2 cm below inferior edge and 2 cm right and left of the midline Essentials of Sleep Technology Manual 2.1 EOG: if M2 fails reference E1 &E2 to M1 EMG – “chin z” (above mandible) fails?? ‐ Fix if possible ‐ otherwise reference Chin 1 & Chin 2 to each other Essentials of Sleep Technology EEG Derivations • Recommended • • • • F4‐M1 C4‐M1 O2‐M1 Back up electrodes at F3, C3, O1, referred to M2 electrode F3 M1 C3 O1 • Alternative • • • • C4 M2 O2 FPz Fz‐Cz Cz‐Oz C4‐M1 Back up electrodes at Fpz, C3, O1, M2 FZ M1 Essentials of Sleep Technology Classification of EEG Activity • • • • F4 Frequency Duration Amplitude Waveform morphology Essentials of Sleep Technology CZ M2 OZ Frequency Frequency ‐ cycles / second (cps) or hertz (Hz) 15 CPS (Hz) 10 Hz 28 Hz 5 Hz 3 Hz Essentials of Sleep Technology Frequency Patterns • Rhythmic (alpha) • Mixed frequency (theta, beta) Essentials of Sleep Technology Duration of a Waveform seconds Essentials of Sleep Technology Amplitude • Function of • voltage • sensitivity setting • inter‐electrode distance Deflection(mm) = Voltage / Sensitivity • Relative terms; low, medium, high Essentials of Sleep Technology EEG Frequency Classification • • • • • Slow wave: 0.5 ‐2.0 Hz Delta : 0‐3.99 Hz Theta : 4‐7.99 Hz Alpha : 8‐13 Hz Beta : >13 Hz Essentials of Sleep Technology Sleep Staging Delta Activity • • • • • Slow waves ‐ frequency of .5‐2.0 Hz Delta waves 0‐3.99 Hz Amplitude of > 75µV (micro volts) Maximal in Frontal EEG N3 (NREM 3) Essentials of Sleep Technology Theta Activity • Frequency : 4 – 7.99 Hz • No amplitude criteria • 4‐7 Hz Low amplitude, mixed frequency, (LAMF) • The most common sleep frequency Essentials of Sleep Technology Theta or Delta Activity • 4‐7 Hz considered “pathologic” should not be considered N1 sleep • Slow wave criteria should not be considered N3 Examples: encephalopathy or epilepsy Essentials of Sleep Technology Alpha Activity • • • • Frequency : 8‐13 Hz Maximal in occipital leads (O1, O2, ) Variable amplitude Wake, relaxed Essentials of Sleep Technology 1 second Beta Activity Frequency : > 13 Hz Waves compressed at 10 mm/s Low amplitude, mixed frequency Wake, eyes open • • • • Essentials of Sleep Technology EEG Classification and Sleep Staging • Frequency – cps/Hz • Amplitude (microvolts) • Presence of sleep‐specific waveforms : • • • • Vertex Sharp Wave Sleep Spindle , K complex “Sawtooth” wave Defined by duration and/ or morphology Essentials of Sleep Technology Vertex Sharp Waves • Sharply contoured waves with duration <0.5 sec. • Maximal over central region and distinguished from background activity • Characteristic of N1 Essentials of Sleep Technology Stage 2 “Markers” • • • • • Spindle K complex Spindle maximal with central EEG K complex maximal with frontal EEG** Both decline in density with age Crowley, K. et al. The effects of normal aging on sleep spindle and K‐complex production. Clin Neurophysiol 2002; 113:1615‐22 Essentials of Sleep Technology Sleep Spindle • Sleep Spindle ‐ 12‐14 cps. (11‐16 Hz) • > 0.5 seconds • .5 second spindles ‐ 6‐7 cycles • 2‐4/minute in young adults, but varies • Benzodiazepine hypnotics increase density 1 second .5 sec. Essentials of Sleep Technology Spindles and Digital PSG 30 second page Essentials of Sleep Technology Spindles and Digital PSG 10 second page Essentials of Sleep Technology Medication Effect Spindles 10 second page Essentials of Sleep Technology Medication Effect Spindles (Zoomed) 10 second page Essentials of Sleep Technology K Complex • Well‐delineated, negative sharp wave followed by a positive deflection • Duration: at least 0.5 seconds • No specific amplitude criteria (distinct from background) • May be spontaneous or associated with arousal • Tend to recur 1.0‐1.7 / min. • May be underscored from Central EEG Essentials of Sleep Technology Stage 2 Essentials of Sleep Technology Summary of Sleep Waveforms Central Delta • (0.5-2 cps) Occipital • > 75 Central Theta • (4-7 cps) Alpha Occipital Central • (8-13 cps) Occipital Sleep spindle Central • (12-14 cps) • >0.5 sec. Occipital K Complex • >0.5 sec. Central Occipital Essentials of Sleep Technology Sleep Stages Identification and Scoring Essentials of Sleep Technology Stage W (Wakefulness) • EEG • >15 sec. rhythmic alpha (8‐13 cps) • Low amplitude, mixed frequency (LAMF), mostly beta • EOG • Voluntary rapid eye movements or blinks • involuntary slow eye movements (SEM’s) • EMG • Variable amplitude, usually higher than during sleep stages Essentials of Sleep Technology Stage Wake Eyes Closed vs. Eyes Open Central EEG Occipital EEG 9 Hz alpha LAMF (Beta) Essentials of Sleep Technology Stage Wake Eyes Closed vs. Eyes Open Central EEG Alpha Occipital EEG SEMs Essentials of Sleep Technology Beta REM Eye movement Definitions • Blinks: Conjugate vertical eye movements; 0.5‐2 Hz present in wake • Reading eye movements: Trains of conjugate eye movements consisting of a slow phase followed by a rapid phase in the opposite direction • Slow eye movements (SEM): Conjugate, reasonably regular, sinusoidal eye movements with an initial deflection usually lasting >500 msec • Rapid eye movements (REM): Conjugate, irregular, sharply peaked eye movements with initial deflection usually lasting <500 msec Essentials of Sleep Technology Wake (drowsy) Note variable slope of eye movements Essentials of Sleep Technology Wake Eye Movements / Blinks Eye movements blinks Essentials of Sleep Technology Drowsy Eye Movements Essentials of Sleep Technology REM Eye Movements Essentials of Sleep Technology Stage 1 (N1) • EEG • • • • < 50% alpha Low amplitude, mixed frequency (LAMF) May have vertex sharp waves No K complex or spindles (in 1st half of epoch) • EOG • Slow eye movements (SEM’s) • EMG • Variable, may decrease from wake • Snore artifact may occur Essentials of Sleep Technology Wake‐Stage 1 transition Central EEG Occipital EEG Essentials of Sleep Technology Unequivocal Stage 1 Cumulative % alpha is <50% Central EEG Occipital EEG Essentials of Sleep Technology Wake‐Stage 1 Transition • From alpha record • Decrease in amount, amplitude and frequency of alpha • From low voltage waking record • Generalized slowing of EEG Essentials of Sleep Technology Stage 1 (N1) For patients who do not generate alpha rhythm • N1 begins with the earliest of any of the following • activity 4‐7 Hz with slowing of background frequencies by ≥1 Hz from those of stage W • vertex sharp waves • Slow eye movements Essentials of Sleep Technology Beta / Theta comparison Beta Theta Essentials of Sleep Technology Beta EEG, eyes open EOG Chin EMG Central EEG Occipital EEG Essentials of Sleep Technology Theta EEG, eyes closed, rolling EOG Chin EMG Central EEG Occipital EEG Essentials of Sleep Technology Epoch 1 - Wake EOG 2 Chin channels Central EEG Occipital EEG Essentials of Sleep Technology Epoch 2 ‐ Wake Essentials of Sleep Technology Epoch 3 ‐Wake Essentials of Sleep Technology Epoch 4 ‐Wake Essentials of Sleep Technology Epoch 5 -Wake Essentials of Sleep Technology Epoch 6‐Wake or 1 Essentials of Sleep Technology Epoch 7 ‐Stage 1 Essentials of Sleep Technology Epoch 8 ‐Stage 1 Essentials of Sleep Technology Another Challenge: Muscle Artifact Occipital EEG Central EEG Essentials of Sleep Technology NREM Sleep Stage 2 (N2) • EEG: • Sleep spindles and/or K Complexes • < 20% high amplitude slow waves • theta background • EOG: • EEG activity, usually no eye movements • EMG: • Tonic activity Essentials of Sleep Technology N1: theta with waves not meeting criteria for K complex or spindle Occipital EEG Central EEG Essentials of Sleep Technology Alpha vs Spindle Central EEG Occipital EEG Essentials of Sleep Technology Previous epoch, stage 1; this begins stage 2 1st half of epoch K complex = spindle Essentials of Sleep Technology Previous epoch, N1; this epoch still N1; next epoch may be N2 K complex or spindle in 2nd half Essentials of Sleep Technology Previous epoch N2, K complex or spindle anywhere in epoch Essentials of Sleep Technology N2 continues; K complex or spindle anywhere in epoch Essentials of Sleep Technology N2 continues without K complex or spindle Essentials of Sleep Technology K complex Identification Aided by Use of Frontal EEG Essentials of Sleep Technology Sleep Onset Confirmed by N2 Essentials of Sleep Technology Epoch 1 Essentials of Sleep Technology Epoch 2 Essentials of Sleep Technology Epoch 3 Essentials of Sleep Technology Epoch 4 Essentials of Sleep Technology Epoch 5 Essentials of Sleep Technology Stage 2, with < 20% (6 seconds) delta Essentials of Sleep Technology Stage 2 with Slow Waves < 20 % delta Essentials of Sleep Technology Ending N2 • Transition to stage W • An arousal (change to N1 until K complex unassociated with arousal or sleep spindle occurs) Essentials of Sleep Technology Stage 2 with movement arousal; next epoch may be W, 1, 2 or REM An Arousal in Stage N2 Epoch 25 26 27 28 C4‐M1 arousal O2‐M1 N2 N2 Chin EMG Essentials of Sleep Technology N1 N2 Ending N2 • Transition to stage W • An arousal • A major body movement Essentials of Sleep Technology Major Body Movement Movement and muscle artifact obscuring the EEG for more than half an epoch to the extent that the sleep stage cannot be determined Essentials of Sleep Technology Major Body Movement • Scoring rules • Stage W if alpha is present for part of the epoch • Stage W if no alpha is present, but Stage W epoch either precedes or follows the epoch with movement • Otherwise, score the epoch as the same stage as the epoch that follows it Essentials of Sleep Technology Major Body Movement, with alpha Stage as Wake Central Essentials of Sleep Technology Major Body Movement: No Alpha 21 22 23 If either epoch 21 or 23 is Stage W, then epoch 22 is Stage W MBM; no alpha Not Stage W MBM; no alpha Not Stage W If neither epoch 21 or 23 is Stage W, then epoch 22 is same stage as epoch 23 Essentials of Sleep Technology Ending N2 • Transition to stage W • An arousal (change to N1 until K complex unassociated with arousal or sleep spindle occurs) • A major body movement followed by low amplitude mixed frequency EEG (theta), without non‐arousal K complex or spindle • N1 if SEMs • N2 if no SEMs Essentials of Sleep Technology Major Body Movement in Stage N2 Epoch 25 26 E1-M2 E2-M2 27 28 No SEMs EMG LAMF EEG C4-M1 N2 O2-M1 N2 N2 N2 N2 Online Technologist Registry Review Major Body Movement in Stage N2 Epoch 25 26 E1-M2 27 28 SEM E2-M2 EMG LAMF EEG C4-M1 N2 O2-M1 N2 N1 Online Technologist Registry Review N1 N2 Ending N2 • Transition to stage W • An arousal • A major body movement followed by low amplitude mixed frequency EEG (theta) • Transition to N3 Essentials of Sleep Technology Stage 3 (N3) • > 20% or more of an epoch, with • 2 Hz or slower and • > 75 V, regardless of age. • spindles may persist Essentials of Sleep Technology High and Low Voltage Slow Waves Left EOG Right EOG 75 Central EEG Occipital EEG 1 sec. Chin EMG Essentials of Sleep Technology Identification of Slow Waves Aided by Use of Frontal EEG Essentials of Sleep Technology 75 Total the percentage of waves that meet the frequency and amplitude criteria Essentials of Sleep Technology Ending N2 • Transition to stage W • An arousal • A major body movement followed by low amplitude mixed frequency EEG (theta) • Transition to N3 • Transition to stage R Essentials of Sleep Technology REM Sleep (Stage R) • Epochs which contain all the following • • • • EEG shows LAMF, no K’s or spindles Chin EMG is low No intervening arousals NO slow eye movements post arousal or W Essentials of Sleep Technology REM Sleep (Stage R) • IF no eye movements: Stage REM: – EEG shows LAMF with no K’s, no spindles – Chin EMG remains low (majority of epoch) – No arousal Essentials of Sleep Technology NOTES: • Segments between 2 K’s, 2 spindles or a K and spindle without intervening REM score as N2 • Segments containing REM w/o K’s or spindles and low chin tone score as REM • Majority of epoch is REM score as REM • Majority of epoch is N2 score as N2 Essentials of Sleep Technology REM Essentials of Sleep Technology Alpha in REM Essentials of Sleep Technology Activity not required, but supportive Sawtooth Waves (2‐6 Hz) Maximal in central EEG transient muscle activity (<0.25 sec.) Essentials of Sleep Technology Sawtooth Wave Pattern in REM Essentials of Sleep Technology REM “ Phasic” “Tonic” 2 minutes Essentials of Sleep Technology Beginning of REM Score REM from the last spindle, K complex Score REM from the point where the EMG amplitude drops to REM level Essentials of Sleep Technology Beginning of REM 1 2 3 4 5 6 7 8 2 2 2 2 2 1 Essentials of Sleep Technology REM REM REM Epoch 34 Epoch 33 Unequivocal REM ‐ go back to epoch 33 REM ‐ go back to epoch 32 Epoch 32 Elevated chin and K complex ‐ Stage 2 REM back to here Epoch 23 Unequivocal REM ‐ back to K complex Epoch 22 Stage 2 Continuation of a Period of Stage R Continue, even in absence of REMs, following 1 or more epochs of Stage R, if: • EEG is LAMF, without K complexes or sleep spindles • Chin EMG remains low Essentials of Sleep Technology End of a Period of Stage R • A transition to stage W or N3 • Increase in chin tone • An arousal occurs: • Followed by LAMF and SEMs, (score N1) • If no SEMs and chin remains low; (stage R) • If major body movement occurs, followed by: • LAMF EEG and SEMs, no non‐arousal K complex or spindle, score N1, • LAMF EEG but not followed by SEMs and chin remains low, score stage R • One or more non‐arousal K complexs or spindles in 1st half of epoch, with no REMs (N2) Essentials of Sleep Technology End of a period of REM (Stage R) A period of RLVMF EEG without eye movements follows REM; score as REM, regardless of the duration, if EMG is at REM level and there are no spindles, K complexes or movement arousals Epoch: 1 3 A Stage R Stage R N2 B Stage R Score REM up to the point of Chin EMG augmentation 2 N1 N2 Stage R N2 C Stage R Essentials of Sleep Technology R R R R SEM R N1 N1 R = Major body movement (no alpha) Essentials of Sleep Technology R R N2 R N2 N2 Non‐arousal K complex or spindle Essentials of Sleep Technology R R POP QUIZ !! Have you been awake? Essentials of Sleep Technology 1. The 3 physiologic measures needed to stage sleep are: a. b. c. d. EMG, EEG, EKG EMG, EOG, EEG EMG, EEG, Limb Movements EEG EKG, BLT Essentials of Sleep Technology 1. The 3 physiologic measures needed to stage sleep are: a. b. c. d. a) b) c) d) EMG, EEG, EKG EMG, EOG, EEG EMG, EEG, Limb Movements EEG EKG, BLT Essentials of Sleep Technology 2. 45 % high amplitude Delta waves in a epoch of sleep is scored: a. b. c. d. Delta waves do not determine stage Stage N2 Stage N3 Stage REM Essentials of Sleep Technology 2. 45 % high amplitude Delta waves in a epoch of sleep is scored: a. b. c. d. Delta waves do not determine stage Stage N2 Stage N3 Stage REM Essentials of Sleep Technology 3. The amplitude criteria for a K complex is at least: a. b. c. d. 50 microvolts 75 microvolts 10 microvolts There is no specific amplitude criteria Essentials of Sleep Technology 3. The amplitude criteria for a K complex is at least: a. b. c. d. 50 microvolts 75 microvolts 10 microvolts There is no specific amplitude criteria Essentials of Sleep Technology 4. The duration of a K complex must be at least: a. b. c. d. 0.5 seconds 1.5 seconds 5 seconds There is no specific duration criteria Essentials of Sleep Technology 4. The duration of a K complex must be at least: a. b. c. d. 0.5 seconds 1.5 seconds 5 seconds There is no specific duration criteria Essentials of Sleep Technology 5. Sleep spindles are typically prominent in which sleep stage? a. b. c. d. Wake Stage 1 Stage 2 Stage 3 Essentials of Sleep Technology 5. Sleep spindles are typically prominent in which sleep stage? a. b. c. d. Wake Stage 1 Stage 2 Stage 3 Essentials of Sleep Technology 6. Chin EMG is usually lowest in which sleep stage? a. b. c. d. REM Stage 1 Stage 2 Stage 3 Essentials of Sleep Technology 6. Chin EMG is usually lowest in which sleep stage? a. b. c. d. REM Stage 1 Stage 2 Stage 3 Essentials of Sleep Technology 7. Which waveform is most clearly seen in the occipital EEG? a. b. c. d. alpha k‐complexes theta delta Essentials of Sleep Technology 7. Which waveform is most clearly seen in the occipital EEG? a. b. c. d. alpha k‐complexes theta delta Essentials of Sleep Technology 8. Slow rolling eye movements may be seen in: a. b. c. d. REM Wake Stage 1 b and c Essentials of Sleep Technology 8. Slow rolling eye movements may be seen in: a. b. c. d. REM Wake Stage 1 b and c Essentials of Sleep Technology 9. Stage? Essentials of Sleep Technology 9. Wake Essentials of Sleep Technology 10. Stage? Essentials of Sleep Technology 10. Stage N1 Essentials of Sleep Technology 11. Stage? Essentials of Sleep Technology 11. Stage N2 Essentials of Sleep Technology 12. Stage? 3 sec 75 Essentials of Sleep Technology 12. Stage N3 75 Essentials of Sleep Technology 13. Stage ? 75 13. Stage N3 75 14. Stage? LOC ROC C3 LOC O2 CHIN Essentials of Sleep Technology 14. Stage REM LOC ROC C3 LOC O2 CHIN Essentials of Sleep Technology 15. Stage? Essentials of Sleep Technology 15. REM Essentials of Sleep Technology
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