RPSGT Best Practices & Methodologies 2 — Questions and Answers
Question 1: What is the maximum acceptable electrode impedance for EEG channels in polysomnography according to AASM guidelines?
- 1 kΩ
- 5 kΩ (Correct answer)
- 10 kΩ
- 25 kΩ
Correct answer: 5 kΩ
AASM guidelines specify that EEG electrode impedance should be ≤5 kΩ to ensure adequate signal quality.
Question 2: During biocalibrations, a technologist asks the patient to breathe normally for 30 seconds. What is the primary purpose of this step?
- Measure baseline oxygen saturation
- Verify respiratory channel function and waveform morphology (Correct answer)
- Calibrate the CPAP pressure gauge
- Test patient cooperation for the study
Correct answer: Verify respiratory channel function and waveform morphology
Normal breathing during biocalibrations verifies that airflow, thoracic, and abdominal respiratory channels display appropriate waveform morphology and function.
Question 3: For the left outer canthus EOG electrode (E1), what is the correct placement according to AASM specifications?
- 1 cm above and 1 cm lateral to the outer canthus
- 1 cm below and 1 cm lateral to the outer canthus (Correct answer)
- Directly on the outer canthus
- 2 cm above the outer canthus
Correct answer: 1 cm below and 1 cm lateral to the outer canthus
E1 is placed 1 cm below and 1 cm lateral to the left outer canthus to capture vertical and horizontal eye movements.
Question 4: What high-frequency filter setting is recommended for EEG channels in polysomnography?
- 15 Hz
- 35 Hz (Correct answer)
- 70 Hz
- 100 Hz
Correct answer: 35 Hz
A high-frequency filter (low-pass) of 35 Hz is recommended for EEG channels to preserve physiologically relevant brain wave activity while reducing high-frequency artifact.
Question 5: A technologist notices 60 Hz artifact on multiple EEG channels. Which action should be performed FIRST?
- Apply a 60 Hz notch filter and continue recording
- Identify and re-prep electrodes with high impedance readings (Correct answer)
- Reboot the acquisition software
- Wake the patient and reapply all electrodes
Correct answer: Identify and re-prep electrodes with high impedance readings
High electrode impedance is the most common cause of 60 Hz (electrical interference) artifact; correcting impedance at affected electrodes should be the first step.
Question 6: When placing chin EMG electrodes for polysomnography, where is the submentalis electrode placed?
- 2 cm above the inferior edge of the mandible on the midline
- 1 cm above the inferior edge of the mandible on the midline (Correct answer)
- On the lateral chin muscle belly
- On the mental protuberance
Correct answer: 1 cm above the inferior edge of the mandible on the midline
The AASM-recommended submentalis EMG electrode is placed 1 cm above the inferior edge of the mandible on the midline.
Question 7: What is the standard recording epoch length used for scoring polysomnography studies?
- 15 seconds
- 20 seconds
- 30 seconds (Correct answer)
- 60 seconds
Correct answer: 30 seconds
The standard epoch length for PSG scoring is 30 seconds, as defined by AASM scoring rules.
RPSGT Best Practices & Methodologies 2
What is the maximum acceptable electrode impedance for EEG channels in polysomnography according to AASM guidelines?