ABEM Evoked Potentials & Late Response Studies 2

Question 1

Following median nerve stimulation, which SSEP peak represents activation at the level of the brachial plexus (Erb's point)?

Accepted Answer

N9

Answer

N9 represents the nerve action potential volley arriving at the brachial plexus, recorded from the ipsilateral supraclavicular fossa (Erb's point).

Question 2

What is the primary clinical application of brainstem auditory evoked potentials (BAEPs)?

Accepted Answer

Evaluating auditory pathway integrity and detecting acoustic neuromas or brainstem lesions

Answer

BAEPs evaluate conduction through the auditory pathway from the cochlea through the brainstem, making them sensitive for acoustic neuromas and demyelinating brainstem lesions.

Question 3

In pattern-reversal visual evoked potentials (VEPs), the P100 wave is generated primarily by which structure?

Accepted Answer

Primary visual cortex (occipital cortex, V1)

Answer

The P100 is a positive deflection at approximately 100 ms recorded over the occipital scalp, reflecting activation of the primary visual cortex (V1).

Question 4

A unilaterally delayed P100 latency with preserved amplitude on VEP testing is most characteristic of which condition?

Accepted Answer

Multiple sclerosis with a history of optic neuritis

Answer

Demyelination of the optic nerve from multiple sclerosis characteristically prolongs the P100 latency, often with preserved amplitude, reflecting slowed rather than lost conduction.

Question 5

Which wave of the brainstem auditory evoked potential (BAEP) is generated by the distal cochlear nerve?

Accepted Answer

Wave I

Answer

Wave I is generated by the distal portion of the eighth cranial nerve (cochlear nerve), representing the most peripheral auditory generator in the BAEP series.

(ABEM) American Board of Electrodiagnostic Medicine Practice Test

(ABEM) American Board of Electrodiagnostic Medicine Practice Test

ABEM Evoked Potentials & Late Response Studies 2