FREE RST Artifact Recognition and Troubleshooting Questions and Answers

Question 1

During a polysomnogram on a patient with a history of obstructive sleep apnea, the technologist notes very low-amplitude, slow, undulating waves across multiple EEG and EOG channels.
The patient appears to be perspiring heavily.
What is the most likely artifact, and what is the best initial troubleshooting step?

Accepted Answer

Sweat artifact; decrease the room temperature and use a fan if possible.

Answer

60 Hz artifact; check the ground electrode and unplug nearby electronics.

Answer

Movement artifact; wait for the patient to settle into a stable position.

Answer

ECG artifact; re-reference the affected channels to a common average.

Question 2

A technologist observes a thick, uniform, fast frequency line in all AC-coupled channels (EEG, EOG, EMG). Which of the following is the most probable cause and first corrective action?

Accepted Answer

60 Hz interference; check the integrity and placement of the common ground electrode.

Answer

Electrode 'pop'; re-prep and reapply the single affected electrode.

Answer

Muscle tension artifact; ask the patient to relax their jaw.

Answer

Pen blocking; recalibrate the amplifier for the affected channels.

Question 3

While monitoring a study, the signal from the nasal pressure transducer becomes flat, while the oronasal thermistor and respiratory effort belts continue to show clear respiratory cycles. What is the most appropriate immediate action for the technologist to take?

Accepted Answer

Check the cannula for displacement or blockages and re-seat it if necessary.

Answer

Reposition the patient's head to open the airway.

Answer

Initiate the emergency response protocol.

Answer

Document the sensor failure and continue monitoring with the remaining signals.

Question 4

A patient is observed bruxing (teeth grinding) during sleep. Which of the following artifacts would be most prominent in the polysomnogram during this activity?

Accepted Answer

High-amplitude, high-frequency activity in the chin EMG and temporal EEG channels.

Answer

Slow, rolling waves in the EOG channels synchronized with respiratory effort.

Answer

Repetitive, sharp spikes in the ECG channel that are not time-locked to the QRS complex.

Answer

A sudden loss of signal in all respiratory effort channels.

Question 5

During a recording, a single, sharp, high-voltage vertical deflection appears in C3-M2 and F3-M2, but not in any other channels. This is most likely an example of:

Accepted Answer

An electrode pop artifact.

Answer

A K-complex, indicating Stage N2 sleep.

Answer

A generalized spike-and-wave discharge.

Answer

Cardioballistic artifact.

Question 6

A technologist notes that the respiratory inductance plethysmography (RIP) belt signals appear flattened and squared-off at the peaks of inspiration and expiration. What is the most likely cause of this artifact?

Accepted Answer

The belts are too tight, causing the signal to clip at its maximum range.

Answer

The patient is having central apneas.

Answer

The belts are too loose and are moving with the bed sheets.

Answer

The filter settings for the effort channels are incorrect.