RPSGT RPSGT Electroencephalography & Signal Interpretation 2 — Questions and Answers
Question 1: The epoch length recommended by AASM for adult PSG sleep scoring is:
- 20 seconds
- 30 seconds (Correct answer)
- 60 seconds
- 10 seconds
Correct answer: 30 seconds
AASM guidelines specify 30-second epochs as the standard unit for adult polysomnographic sleep staging, retained from the original Rechtschaffen and Kales manual.
Question 2: Vertex sharp waves (V waves) are associated with which sleep stage?
- REM sleep
- N2 sleep
- N1 sleep (Correct answer)
- N3 sleep
Correct answer: N1 sleep
Vertex sharp waves are high-amplitude biphasic waveforms maximal at the central (Cz) electrode that appear during N1 sleep, often in response to external stimuli.
Question 3: An EEG arousal during PSG is scored when there is an abrupt EEG frequency shift lasting at least:
- 1 second
- 3 seconds (Correct answer)
- 5 seconds
- 10 seconds
Correct answer: 3 seconds
AASM defines an EEG arousal as an abrupt shift to alpha, theta, or >16 Hz activity lasting ≥3 seconds, preceded by ≥10 seconds of stable sleep.
Question 4: Positive occipital sharp transients of sleep (POSTS) are normal EEG variants that occur during which stages?
- Wakefulness with eyes closed
- N1 and N2 sleep (Correct answer)
- N3 sleep
- REM sleep
Correct answer: N1 and N2 sleep
POSTS are triangular, surface-positive sharp waves at occipital electrodes that are benign normal variants occurring during N1 and N2 NREM sleep.
Question 5: Mixed frequency low-amplitude EEG combined with low chin EMG tone defines which sleep stage?
- N1
- N2
- N3
- REM (Correct answer)
Correct answer: REM
REM sleep is identified by mixed frequency low-amplitude EEG resembling wakefulness, combined with low chin EMG tone and often rapid eye movements.
Question 6: Phasic chin muscle activity (transient muscle activity) during REM is scored when bursts last:
- 0.1–0.5 seconds
- 0.25–0.5 seconds (Correct answer)
- 0.5–1.0 seconds
- 1.0–2.0 seconds
Correct answer: 0.25–0.5 seconds
AASM defines phasic chin EMG bursts during REM as lasting 0.25–0.5 seconds with amplitude at least 4× the background EMG level.
RPSGT RPSGT Electroencephalography & Signal Interpretation 2
The epoch length recommended by AASM for adult PSG sleep scoring is: