RPSGT RPSGT Sleep Staging & Scoring 2

Question 1

What distinguishes Stage N1 from Stage Wake in a subject who generates occipital alpha rhythm?

Accepted Answer

Alpha activity present for <50% of the epoch

Answer

N1 is scored when alpha activity occupies <50% of the epoch, replaced by low-amplitude mixed-frequency activity.

Question 2

Sawtooth waves during polysomnography are most commonly associated with which sleep stage?

Accepted Answer

REM

Answer

Sawtooth waves (2–6 Hz, notched waveforms) are a characteristic feature of REM sleep, often preceding bursts of rapid eye movements.

Question 3

An EEG frequency shift qualifies as an arousal in AASM scoring if it lasts a minimum of how many seconds?

Accepted Answer

3 seconds

Answer

AASM defines an arousal as an abrupt EEG frequency shift lasting ≥3 seconds, preceded by ≥10 seconds of stable sleep.

Question 4

Which of the following correctly states the amplitude criterion for slow wave activity in N3 scoring?

Accepted Answer

Peak-to-peak >75 µV in frontal leads

Answer

AASM requires slow waves to have peak-to-peak amplitude >75 µV measured over the frontal derivations.

Question 5

What frequency range defines the theta activity that predominates in Stage N1 sleep?

Accepted Answer

4–7 Hz

Answer

Theta activity (4–7 Hz) is the predominant EEG frequency in Stage N1, replacing the alpha rhythm seen during wakefulness.

RPSGT Exam Practice Test