Electrode Placement and Montages Flashcards

In the 10-20 system, which electrode is located at the vertex of the skull?

Answer: Cz

Cz is located at the vertex (top) of the skull at the intersection of the midline and a line connecting the two ears.

What does a referential montage compare each electrode to?

Answer: A common reference electrode

In a referential montage, each active electrode is compared to a single common reference electrode, often placed at the ear or linked mastoids.

Which electrode placement best captures activity from the temporal lobe?

Answer: T3/T4 (T7/T8)

T3/T4 (now called T7/T8 in the revised system) are positioned over the temporal lobes and best capture temporal lobe activity.

What is the purpose of the ground electrode in an EEG recording?

Answer: To reduce common-mode noise and electrical interference

The ground electrode helps the amplifier reject common-mode noise and electrical interference by providing a reference point for the differential amplifier.

In a bipolar longitudinal montage, what is the typical chain order for the left hemisphere?

Answer: Fp1-F3-C3-P3-O1

The standard longitudinal bipolar (double banana) chain runs from front to back: Fp1-F3-C3-P3-O1 for the left parasagittal chain.

Which statement about electrode impedance is correct for clinical EEG?

Answer: Impedance should be below 5 kΩ for optimal recording

Electrode impedance should be below 5 kΩ (ideally 1-5 kΩ) to ensure adequate signal quality and minimize noise artifacts.

What does the '10' and '20' refer to in the International 10-20 system?

Answer: Percentage of total skull distance between electrode sites

The 10 and 20 refer to the percentage of the total front-to-back or left-to-right skull distance used as the spacing between electrode positions.