EEG Evoked Potentials 3

Question 1

For pattern reversal visual evoked potential (VEP) testing, how should each eye be stimulated?

Accepted Answer

Monocularly (one eye at a time, other occluded)

Answer

Both eyes open simultaneously

Answer

With both eyes viewing through a red-green filter

Answer

With pupils pharmacologically dilated

Question 2

What are the typical high-pass and low-pass filter settings used when recording brainstem auditory evoked potentials (BAEPs)?

Accepted Answer

100–3000 Hz

Answer

0.1–30 Hz

Answer

1–100 Hz

Answer

1000–10000 Hz

Question 3

The 'N13' potential recorded at the cervical spine (Cv5 or Cv7 electrode) during median nerve SSEP is generated by which structure?

Accepted Answer

Dorsal horn/dorsal column nuclei at the cervicomedullary junction

Answer

Brachial plexus Erb's point

Answer

Ventral posterior lateral thalamus

Answer

Primary somatosensory cortex

Question 4

Approximately how many stimulus repetitions (averages) are typically needed to obtain a reliable, reproducible BAEP waveform?

Accepted Answer

1000–2000

Answer

50–200

Answer

300–500

Answer

5000–10000

Question 5

What is the primary clinical advantage of flash VEPs over pattern reversal VEPs?

Accepted Answer

Can be performed in uncooperative or visually impaired patients unable to fixate on a pattern

Answer

Greater sensitivity for demyelinating optic nerve disease

Answer

Shorter recording time due to lower averaging requirement

Answer

Better amplitude resolution of cortical responses

Question 6

Which peripheral nerve is most commonly stimulated at the ankle when performing lower extremity somatosensory evoked potential (SSEP) testing?

Accepted Answer

Posterior tibial nerve

Answer

Femoral nerve

Answer

Sciatic nerve

Answer

Common peroneal nerve

Question 7

Signal averaging in evoked potential recording improves waveform clarity primarily because:

Accepted Answer

The evoked response is time-locked to the stimulus while background EEG cancels out with repeated averaging

Answer

It amplifies the stimulus artifact to improve timing reference

Answer

It eliminates biological noise by randomizing it across trials

Answer

It increases the stimulation frequency proportional to the number of averages