CNIM Electroencephalography (EEG) in the Operating Room 2

Question 1

Burst suppression on intraoperative EEG is BEST described as:

Accepted Answer

Alternating periods of complete electrocerebral silence and bursts of mixed-frequency activity

Answer

Continuous high-amplitude delta activity without interruption

Answer

Persistent 3 Hz spike-and-wave discharges throughout the recording

Answer

Generalized increase in beta activity with superimposed muscle artifact

Question 2

During carotid endarterectomy, which EEG change is MOST indicative of cerebral ischemia following carotid cross-clamping?

Accepted Answer

Unilateral amplitude reduction and frequency slowing ipsilateral to the clamp

Answer

Bilateral increase in alpha power

Answer

Appearance of bilateral sleep spindles

Answer

Generalized beta activity increase across all channels

Question 3

Which anesthetic agent is most associated with producing epileptiform EEG discharges during induction?

Accepted Answer

Etomidate

Answer

Propofol

Answer

Isoflurane

Answer

Sevoflurane

Question 4

As anesthetic depth progressively increases, the general EEG pattern shifts:

Accepted Answer

From faster frequencies (beta/alpha) toward slower frequencies (theta then delta)

Answer

From delta slowing toward faster beta activity

Answer

Remains stable at alpha frequencies regardless of depth

Answer

Immediately transitions to isoelectric silence without intermediate stages

Question 5

At typical surgical maintenance doses of propofol (TIVA), the characteristic EEG pattern is:

Accepted Answer

Alpha oscillations and spindle-like beta activity (the 'propofol alpha')

Answer

Continuous high-amplitude delta with no faster frequencies

Answer

Persistent burst suppression throughout the case

Answer

Completely isoelectric (flat) tracing

Question 6

Focal EEG slowing isolated to the left temporal region during cerebrovascular surgery MOST likely indicates:

Accepted Answer

Regional cerebral dysfunction, such as ischemia or structural compromise

Answer

A normal variant of the aging brain

Answer

Artifact from a poorly placed electrode

Answer

The expected effect of neuromuscular blocking agents

Question 7

Electrocerebral silence (ECS) discovered during intraoperative EEG monitoring requires the neurophysiologist to FIRST:

Accepted Answer

Verify technical factors such as electrode connections, sensitivity settings, and amplifier function before clinical interpretation

Answer

Immediately declare brain death and notify the surgeon

Answer

Increase the high-frequency filter to reveal hidden activity

Answer

Administer a reversal agent to the anesthesiologist