Certified Polysomnographic Technician Certification Certified Polysomnographic Technician Certification Equipment Setup & Calibration 1 — Questions and Answers
Question 1: What is the purpose of performing a biocalibration at the start of a PSG study?
- To set the amplifier gain for all channels
- To verify electrode and sensor function by having the patient perform specific maneuvers (Correct answer)
- To calibrate the CPAP titration pressure
- To synchronize the PSG system clock with the hospital network
Correct answer: To verify electrode and sensor function by having the patient perform specific maneuvers
Biocalibration involves having the patient perform specific maneuvers (eyes open/closed, looking left/right, breathing tasks) to confirm all electrode and sensor signals are accurate before sleep.
Question 2: Which electrode impedance value is considered acceptable for PSG EEG recordings per AASM standards?
- Less than 1 kΩ
- Less than 5 kΩ (Correct answer)
- Less than 10 kΩ
- Less than 20 kΩ
Correct answer: Less than 5 kΩ
AASM standards require electrode impedance to be less than 5 kΩ (ideally ≤5 kΩ) to ensure adequate signal quality for EEG recording.
Question 3: What does a 60 Hz (or 50 Hz) notch filter remove from the PSG signal?
- Muscle artifact
- Electrode pop artifact
- Electrical line noise interference (Correct answer)
- Cardiac artifact
Correct answer: Electrical line noise interference
The notch filter eliminates power line frequency interference (60 Hz in the US, 50 Hz in Europe) that can contaminate biological signals.
Question 4: For proper nasal airflow monitoring in PSG, which sensor is preferred for detecting hypopneas per AASM guidelines?
- Thermocouple
- Nasal pressure transducer (Correct answer)
- End-tidal CO2 sensor
- Piezo respiratory belt
Correct answer: Nasal pressure transducer
AASM recommends a nasal pressure transducer as the preferred sensor for detecting hypopneas because it is more sensitive to partial airflow reductions than a thermocouple.
Question 5: Where is the recommended placement site for the pulse oximetry probe to obtain the most reliable SpO2 readings during PSG?
- Earlobe
- Finger (index or middle) (Correct answer)
- Forehead
- Toe
Correct answer: Finger (index or middle)
The finger (typically index or middle finger) is the standard placement site for pulse oximetry during PSG due to reliable perfusion and signal stability.
Question 6: Which conductive medium is used to lower electrode impedance and ensure good electrical contact between scalp electrodes and the skin?
- Isopropyl alcohol
- Electrode gel or paste (Correct answer)
- Normal saline
- Petroleum jelly
Correct answer: Electrode gel or paste
Electrode gel or conductive paste is applied to scalp electrodes to reduce impedance and ensure stable, low-noise electrical contact between the electrode and skin.
Certified Polysomnographic Technician Certification Certified Polysomnographic Technician Certification Equipment Setup & Calibration 1
What is the purpose of performing a biocalibration at the start of a PSG study?