EEG Artifact Identification 2

Question 1

Which artifact appears as a regular, rhythmic waveform at the same frequency as the patient's heart rate?

Accepted Answer

Pulse artifact (ECG artifact)

Answer

Pulse artifact appears as rhythmic waveforms synchronous with the cardiac cycle, caused by electrode placement over a pulsating blood vessel or by ballistocardiographic effect.

Question 2

Eye blink artifact is primarily seen at which electrode positions?

Accepted Answer

Frontal electrodes (Fp1, Fp2)

Answer

Eye blink artifact produces high-amplitude positive deflections most prominent at Fp1 and Fp2 because the cornea (positive pole of the eye dipole) moves upward toward these frontopolar electrodes during blinking.

Question 3

What is the most effective method for reducing 60 Hz electrical interference artifact?

Accepted Answer

Ensuring all electrode impedances are balanced and below 5 kOhm

Answer

Balanced, low impedances (below 5 kOhm) allow the differential amplifier to effectively reject common-mode 60 Hz noise. Impedance imbalance between electrodes is the primary cause of excessive 60 Hz artifact.

Question 4

Glossokinetic artifact is caused by movement of which structure?

Accepted Answer

The tongue, which acts as an electrical dipole

Answer

The tongue has a tip-negative, base-positive electrical dipole. Tongue movements generate slow potentials that are transmitted to scalp electrodes, particularly in frontal and temporal regions.

Question 5

An electrode pop artifact on EEG is characterized by:

Accepted Answer

Abrupt, high-amplitude deflection confined to a single channel

Answer

Electrode pop appears as a sudden, high-amplitude spike-like deflection isolated to one channel, caused by abrupt impedance change at a single electrode due to drying gel, poor contact, or mechanical disturbance.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Artifact Identification 2