EEG Evoked Potentials 4

Question 1

Which VEP component is most commonly used clinically to detect demyelinating disease of the optic nerve?

Accepted Answer

P100

Answer

The P100 component of the VEP is the most clinically relevant peak; a delayed latency (>115 ms) strongly suggests optic nerve demyelination.

Question 2

In brainstem auditory evoked potentials (BAEPs), Wave V originates primarily from which structure?

Accepted Answer

Lateral lemniscus/inferior colliculus

Answer

Wave V of the BAEP is generated by the lateral lemniscus and inferior colliculus region of the upper brainstem.

Question 3

What does a prolonged I–III interpeak interval in BAEPs indicate?

Accepted Answer

Pontine lesion between cochlear nucleus and superior olive

Answer

The I–III interpeak interval reflects conduction time through the lower brainstem (caudal pons), so prolongation indicates a lesion in that segment.

Question 4

During intraoperative monitoring with somatosensory evoked potentials, which change should prompt immediate surgical notification?

Accepted Answer

50% amplitude decrease or 10% latency increase

Answer

The universally accepted alarm criterion for intraoperative SSEP is a ≥50% amplitude decrease or ≥10% latency increase from baseline.

Question 5

Pattern-reversal VEPs are preferred over flash VEPs in clinical practice primarily because they:

Accepted Answer

Produce more consistent waveforms with smaller normal variance

Answer

Pattern-reversal stimuli generate highly reproducible P100 components with tight normative ranges, making subtle latency delays more detectable than with flash VEPs.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Evoked Potentials 4