RPSGT RPSGT Sleep Staging & Scoring 5 — Questions and Answers
Question 1: What EEG derivation is recommended by the AASM for detecting slow-wave activity during NREM staging?
- C4-M1
- F4-M1 (Correct answer)
- O2-M1
- T3-M2
Correct answer: F4-M1
The AASM recommends the frontal derivation (F4-M1 or F3-M2) as the primary channel for detecting slow-wave activity because delta is of highest amplitude frontally.
Question 2: During REM scoring, chin EMG tone must be:
- Higher than Stage N2 baseline
- At least as high as the highest NREM EMG
- At its lowest level of the night or lower than NREM baseline (Correct answer)
- Absent entirely with no muscle twitches
Correct answer: At its lowest level of the night or lower than NREM baseline
REM sleep requires chin EMG to be at its lowest level of the night, typically lower than any NREM stage, reflecting muscle atonia.
Question 3: Stage N1 sleep is typically defined by which EEG frequency replacing alpha?
- Delta activity (0.5-2 Hz)
- Theta activity (4-7 Hz) (Correct answer)
- Beta activity (>13 Hz)
- Sigma activity (12-14 Hz)
Correct answer: Theta activity (4-7 Hz)
In N1, alpha is replaced by mixed-frequency low-amplitude activity with predominant theta (4-7 Hz) waveforms.
Question 4: A 30-second epoch shows predominantly Stage N2 features, but a cortical arousal lasting 5 seconds is present in the middle. How should this epoch be scored?
- Score as Wake
- Score as N1 due to the arousal
- Score as N2 — the stage occupying the majority of the epoch (Correct answer)
- Split into two 15-second half-epochs
Correct answer: Score as N2 — the stage occupying the majority of the epoch
Per AASM rules, an epoch is scored by the stage that predominates; a brief arousal does not reclassify the entire epoch unless Wake occupies >50%.
Question 5: Which eye movement feature distinguishes slow eye movements (SEMs) of N1 from the rapid eye movements of Stage R?
- SEMs are conjugate; REMs are disconjugate
- SEMs have sinusoidal waveforms lasting >500 ms; REMs have irregular bursts <500 ms (Correct answer)
- SEMs occur only during alpha activity; REMs occur during delta
- SEMs are recorded on EEG; REMs are recorded on EMG
Correct answer: SEMs have sinusoidal waveforms lasting >500 ms; REMs have irregular bursts <500 ms
SEMs are conjugate sinusoidal deflections with initial deflection lasting >500 ms, whereas REMs are irregular, sharply peaked conjugate movements with initial deflection <500 ms.
Question 6: After an epoch of Stage R, the next epoch has no REMs and ambiguous EEG. Under what condition can it still be scored as Stage R?
- Chin EMG remains low and no arousal or major body movement has occurred (Correct answer)
- At least one sleep spindle is present
- Delta waves comprise less than 20% of the epoch
- The epoch immediately follows a K-complex
Correct answer: Chin EMG remains low and no arousal or major body movement has occurred
Stage R continues across epochs without REMs as long as chin EMG stays low and no arousal, major body movement, or awakening has terminated REM.
Question 7: An epoch of N3 is followed by an epoch with mixed frequencies, low-amplitude EEG, REM bursts, and low chin EMG. This transition is best described as:
- N3 to N2 with spindles
- N3 to Wake
- N3 directly to Stage R (REM rebound) (Correct answer)
- N3 to N1 with vertex waves
Correct answer: N3 directly to Stage R (REM rebound)
Direct transitions from slow-wave sleep (N3) to REM can occur, particularly during early morning hours, and are scored as Stage R when criteria are met.
RPSGT RPSGT Sleep Staging & Scoring 5
What EEG derivation is recommended by the AASM for detecting slow-wave activity during NREM staging?