RPSGT Technology & Tools 2 — Questions and Answers
Question 1: Which filter setting is most appropriate for recording the EEG signal during a standard PSG?
- High-pass 0.3 Hz, Low-pass 35 Hz (Correct answer)
- High-pass 1 Hz, Low-pass 70 Hz
- High-pass 0.1 Hz, Low-pass 15 Hz
- High-pass 5 Hz, Low-pass 100 Hz
Correct answer: High-pass 0.3 Hz, Low-pass 35 Hz
AASM recommends a high-pass filter of 0.3 Hz and low-pass filter of 35 Hz for EEG recording during PSG.
Question 2: What is the recommended paper speed (or display sweep) for standard PSG epoch scoring?
- 5 mm/sec (30-second epochs)
- 10 mm/sec (30-second epochs) (Correct answer)
- 15 mm/sec (20-second epochs)
- 25 mm/sec (10-second epochs)
Correct answer: 10 mm/sec (30-second epochs)
The standard PSG display speed is 10 mm/sec, yielding 30-second epochs as recommended by AASM.
Question 3: A positive occipital sharp transient of sleep (POSTS) is best identified on which EEG derivation?
- F4-M1
- C4-M1
- O2-M1 (Correct answer)
- E1-M2
Correct answer: O2-M1
POSTS are maximal over occipital regions and best seen on O1/O2 derivations referenced to the contralateral mastoid.
Question 4: Which electrode impedance threshold must be met before beginning a PSG recording according to best practice?
- Below 50 kΩ
- Below 25 kΩ
- Below 10 kΩ (Correct answer)
- Below 5 kΩ
Correct answer: Below 10 kΩ
Electrode impedance should be below 10 kΩ (ideally ≤5 kΩ) to ensure adequate signal quality.
Question 5: In digital PSG systems, what does the term 'common mode rejection ratio' (CMRR) refer to?
- The ratio of differential signal gain to common-mode signal gain (Correct answer)
- The ratio of sampling rate to signal bandwidth
- The ratio of A/D converter bits to noise floor
- The ratio of electrode impedance to amplifier input impedance
Correct answer: The ratio of differential signal gain to common-mode signal gain
CMRR measures the amplifier's ability to reject noise common to both inputs while amplifying only the differential (brain) signal.
Question 6: During oximetry calibration, a signal averaging time of 3 seconds vs. 6 seconds primarily affects which oximetry characteristic?
- Absolute SpO2 accuracy at baseline
- Detection sensitivity for rapid desaturations (Correct answer)
- The probe's light wavelength output
- Alarm threshold levels
Correct answer: Detection sensitivity for rapid desaturations
Shorter averaging times (3 sec) detect rapid desaturations more sensitively, while longer averaging (6 sec) smooths out motion artifact.
Question 7: Which PSG channel is MOST useful for distinguishing cardiac artifact from true slow-wave EEG activity?
- EMG chin
- ECG (single-lead) (Correct answer)
- Respiratory effort belt
- Position sensor
Correct answer: ECG (single-lead)
The ECG channel allows identification of QRS-timed artifacts in EEG channels, distinguishing them from genuine delta waves.
RPSGT Technology & Tools 2
Which filter setting is most appropriate for recording the EEG signal during a standard PSG?