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Scoring Workshop. SLEEP STAGES. Stage Wake. Stage W corresponds to the waking state. It is characterized by alpha (8-<13 Hz) activity and/or a low voltage, mixed frequency EEG. Alpha attenuates with eye opening. STAGE WAKE. Stage 1.
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Scoring Workshop SLEEP STAGES
Stage Wake • Stage W corresponds to the waking state. It is characterized by alpha (8-<13 Hz) activity and/or a low voltage, mixed frequency EEG. Alpha attenuates with eye opening.
Stage 1 • Stage 1 is defined by a relatively low voltage, mixed frequency EEG with a prominence of activity in the theta (2-<8 Hz) range. Vertex sharp waves may appear and slow-rolling eye movements will often be present. Alpha drops to < 50% of the epoch.
TYPICAL EPOCH OF STAGE I SLEEP - GREATER THAN 50% OF THE EPOCH IS THETA (4-7 Hz). - THERE ARE SLOW, ROLLING EYE MOVEMENTS IN THE EOG. - THE CHIN EMG GENERALLY DECREASES IN AMPLITUDE FROM THE PREVIOUS. EPOCHS OF WAKE. - IN NORMAL YOUNG ADULTS, STAGE I REPRESENTS 2% TO 5% OF NOCTURNAL SLEEP.
Stage 2 • This stage is defined by the presence of sleep spindles (12-14 Hz) and/or K-complexes. Sleep spindles are >.5 sec in duration. K-complexes are well delineated negative (upward) sharp wave which is immediately followed by a positive (downward) component the total duration should exceed .5 sec.
Stage 3 • Stage 3 is defined by an EEG record in which at least 20% but not more than 50% of the epoch consists of waves of 4 Hz which have amplitudes 75V from peak to peak.
TYPICAL EPOCH OF STAGE III SLEEP - STAGE III SLEEP CONSISTS OF BETWEEN 20% AND 50% DELTA WAVES. - DELTA WAVES HAVE A FREQUENCY OF BETWEEN 0.5 AND 3 Hz. - IN NORMAL YOUNG ADULTS, STAGE III REPRESENTS 3% TO 8% OF NOCTURNAL SLEEP.
Stage 4 • Stage 4 is defined by an EEG record in which more than 50% of the epoch consists of waves of 4 Hz which have amplitudes 75 V peak to peak.
TYPICAL EPOCH OF STAGE IV SLEEP - GREATER THAN 50% OF THE EPOCH IS DELTA WAVES (0.5 - 3 Hz). - STAGE III AND STAGE IV SLEEP ARE ALSO CALLED SLOW WAVE OR DELTA SLEEP. - THE AMPLITUDE OF DELTA WAVES IS GENERALLY 75 uV OR GREATER, ALTHOUGH THIS CRITERIA IS DEBATABLE. - IN NORMAL YOUNG ADULTS, STAGE IV REPRESENTS 20% TO 25% OF NOCTURNAL SLEEP.
Stage REM • REM is defined by the appearance of relatively low voltage, mixed frequency EEG activity and episodic Rapid Eye Movements. Distinctive “saw-tooth” waves are seen frequently, but not always. Saw-tooth waves are in the theta frequency range and may be notched.
STAGE WAKE STAGE I STAGE II STAGE III STAGE IV REM EEG