CNIM Electroencephalography (EEG) in the Operating Room

Question 1

What is the standard electrode placement system used for intraoperative EEG monitoring?

Accepted Answer

10-20 International System

Answer

10-10 Extended System

Answer

Modified Combinatorial Nomenclature

Answer

Bipolar Anterior-Posterior System

Question 2

Which EEG frequency band is typically dominant during relaxed wakefulness with eyes closed?

Accepted Answer

Alpha (8–13 Hz)

Answer

Delta (0.5–4 Hz)

Answer

Theta (4–8 Hz)

Answer

Beta (13–30 Hz)

Question 3

What type of EEG montage references each electrode to the mathematical average of all scalp electrodes?

Accepted Answer

Common average reference montage

Answer

Bipolar chain montage

Answer

Linked-ears referential montage

Answer

Laplacian montage

Question 4

Which filter setting is MOST appropriate for eliminating 60 Hz power line interference in intraoperative EEG?

Accepted Answer

Notch filter at 60 Hz

Answer

High-pass filter at 70 Hz

Answer

Low-pass filter at 1 Hz

Answer

Band-pass filter at 100–300 Hz

Question 5

What electrode impedance level is considered acceptable for reliable intraoperative EEG recording?

Accepted Answer

Less than 5 kΩ

Answer

10–20 kΩ

Answer

25–50 kΩ

Answer

Greater than 100 kΩ

Question 6

What does increasing the 'sensitivity' setting on an EEG machine accomplish?

Accepted Answer

It enlarges the displayed waveforms by decreasing the µV/mm value

Answer

It increases the number of electrodes sampled per second

Answer

It reduces the amplitude of the displayed waveforms by increasing the µV/mm value

Answer

It shifts the recording bandwidth toward higher frequencies

Question 7

In intraoperative EEG, a bipolar montage differs from a referential montage in that it:

Accepted Answer

Compares adjacent electrodes to one another in a chain

Answer

Compares each electrode to a single distant reference

Answer

Averages all electrodes into a single summary channel

Answer

Uses only four electrodes placed over the temporal lobes