Scoring Artifacts and Troubleshooting Flashcards

A 60 Hz artifact appearing simultaneously on ALL EEG channels most likely indicates a problem with which electrode?

Answer: The ground or reference electrode

When 60 Hz artifact appears on every channel at once, the common element — the ground or reference electrode — is the most likely source rather than individual recording electrodes.

ECG (cardiogenic) artifact in EEG channels is identified by:

Answer: Regular sharp deflections that align with QRS complexes on the ECG channel

ECG artifact appears as regular spikes in EEG that align precisely with QRS complexes, caused by cardiac electrical activity spreading to scalp electrodes.

Sweat artifact in a PSG EEG recording is characterized by:

Answer: Very slow, large-amplitude undulating baseline shifts below 0.5 Hz

Sweat artifact produces very slow, large-amplitude baseline undulations below 0.5 Hz as ionic changes in perspiration alter electrode potential.

An electrode pop artifact is best identified by:

Answer: A sudden sharp deflection or step change isolated to a single channel

An electrode pop is caused by a momentary change in electrode impedance, producing a sudden sharp deflection or offset in only the affected single channel.

Muscle (EMG) artifact in EEG channels is characterized by:

Answer: High-frequency irregular activity typically above 100 Hz that obscures the EEG signal

Muscle artifact appears as fast, irregular, high-frequency activity (often >100 Hz) that rides on the EEG, making underlying brain activity difficult to score.

When an electrode shows high impedance during PSG, what is the correct first troubleshooting step?

Answer: Re-prep the skin, reapply conductive gel, and re-seat the electrode

High impedance most commonly results from inadequate skin preparation or insufficient conductive medium; re-abrading the skin and reapplying gel usually resolves it.