EEG Artifact Identification 5

Question 1

A lateral eye movement artifact in a bipolar longitudinal montage will appear with opposite polarity at:

Accepted Answer

F7 and F8

Answer

Lateral eye movements produce opposite-polarity deflections at F7 and F8 because the corneal-retinal potential approaches one side and recedes from the other.

Question 2

Which of the following features best distinguishes tremor artifact from a true EEG rhythm?

Accepted Answer

Tremor artifact has a fixed frequency matching the patient's tremor rate

Answer

Tremor artifact mirrors the physiological tremor frequency (4–6 Hz for Parkinson's, 8–12 Hz for essential tremor) and correlates with observed limb movement.

Question 3

A technologist uses a short-time constant (high-pass filter increase) to reduce which type of artifact?

Accepted Answer

Slow sweat artifact

Answer

Increasing the high-pass (low frequency) filter shortens the time constant and attenuates slow, DC-shift sweat artifact.

Question 4

During sleep recording, repetitive, high-amplitude spike-like potentials appearing synchronously with each heartbeat across all leads are best identified as:

Accepted Answer

Cardiac (EKG) artifact

Answer

EKG artifact produces spike-like potentials synchronous with the R-wave, often mistaken for epileptiform discharges if the ECG channel is not reviewed.

Question 5

Which montage change is most useful for confirming that a suspected artifact is truly artifactual rather than cerebral?

Accepted Answer

Switching between bipolar and referential montages

Answer

True cerebral activity maintains consistent field distributions across montages, while artifacts often appear or disappear inconsistently when the montage is changed.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Artifact Identification 5