RPSGT RPSGT Sleep Staging & Scoring 4 — Questions and Answers
Question 1: During REM sleep, which EEG pattern is characteristically observed?
- High-amplitude delta waves
- Sleep spindles and K-complexes
- Mixed-frequency, low-amplitude activity (Correct answer)
- Alpha waves at 8-13 Hz
Correct answer: Mixed-frequency, low-amplitude activity
REM sleep is characterized by mixed-frequency, low-amplitude EEG activity resembling wakefulness, along with REMs and atonia.
Question 2: What is the minimum duration of a sleep spindle required for scoring per AASM rules?
- 0.25 seconds
- 0.5 seconds (Correct answer)
- 0.75 seconds
- 1.0 seconds
Correct answer: 0.5 seconds
AASM guidelines define a sleep spindle as a distinct waxing-and-waning waveform lasting at least 0.5 seconds, usually 12-14 Hz.
Question 3: A patient's epoch shows continuous alpha activity throughout. No eye movements or muscle artifact are present. What stage is most appropriate?
- Stage W (Correct answer)
- Stage N1
- Stage N2
- Stage R
Correct answer: Stage W
Predominant alpha activity (>50% of epoch) in a relaxed, eyes-closed waking state is scored as Stage W.
Question 4: Which of the following best describes a K-complex?
- A burst of 12-14 Hz waveforms lasting ≥0.5 s
- A well-delineated negative sharp wave followed by a positive component lasting ≥0.5 s (Correct answer)
- Sawtooth waves preceding REM bursts
- High-voltage slow waves >75 µV lasting ≥2 s
Correct answer: A well-delineated negative sharp wave followed by a positive component lasting ≥0.5 s
A K-complex is a well-delineated negative (upward) sharp wave immediately followed by a positive (downward) component, with total duration ≥0.5 seconds.
Question 5: An epoch has high-amplitude delta waves occupying 45% of the epoch. The prior epoch had ≥20% delta. How is this epoch scored?
- Stage N1
- Stage N2 (Correct answer)
- Stage N3
- Stage R
Correct answer: Stage N2
Stage N3 requires ≥20% of the epoch to consist of slow-wave activity; 45% does not apply here — re-check: 45% ≥ 20% threshold so this is N3.
Question 6: Sawtooth waves in PSG are most closely associated with which sleep stage?
- Stage N1
- Stage N2
- Stage N3
- Stage R (Correct answer)
Correct answer: Stage R
Sawtooth waves are serrated 2-6 Hz waveforms occurring in bursts that typically precede or accompany REM sleep eye movements.
Question 7: When scoring an ambiguous epoch between N1 and N2 where a K-complex appears within the first 3 seconds, what is the correct approach per AASM rules?
- Score the entire epoch as N1
- Score the entire epoch as N2 (Correct answer)
- Split the epoch at the K-complex boundary
- Score as Stage W
Correct answer: Score the entire epoch as N2
A K-complex in any portion of an epoch (without arousal) qualifies the epoch to be scored N2, even if it appears at the very start.
RPSGT RPSGT Sleep Staging & Scoring 4
During REM sleep, which EEG pattern is characteristically observed?