EEG Evoked Potentials

Question 1

What are the three main types of evoked potentials commonly recorded in a clinical neurophysiology laboratory?

Accepted Answer

Visual, Auditory, and Somatosensory

Answer

The three main clinical evoked potentials are Visual (VEP), Auditory (BAEP/ABR), and Somatosensory (SSEP), each assessing a different sensory pathway.

Question 2

Which evoked potential modality is specifically used to assess the integrity of the auditory pathway from the cochlea through the brainstem?

Accepted Answer

Brainstem Auditory Evoked Potentials (BAEP)

Answer

BAEPs (also called ABRs) record far-field potentials generated along the auditory nerve and brainstem from cochlea to inferior colliculus.

Question 3

What is the primary waveform of clinical interest in a pattern reversal visual evoked potential (VEP)?

Accepted Answer

P100

Answer

The P100 is the large positive peak occurring around 100 ms, generated in primary visual cortex, and is the most reliable and clinically significant component of the pattern reversal VEP.

Question 4

Stimulation of the median nerve in a somatosensory evoked potential (SSEP) study produces a cortical response designated N20 at approximately what latency in a normal adult?

Accepted Answer

18–21 ms

Answer

The N20 cortical potential following median nerve stimulation peaks at approximately 18–21 ms in normal adults, reflecting conduction time from wrist to primary somatosensory cortex.

Question 5

In brainstem auditory evoked potentials (BAEPs), Wave V is generated primarily by which structure?

Accepted Answer

Lateral lemniscus/inferior colliculus region

Answer

Wave V of the BAEP is generated at or near the lateral lemniscus and inferior colliculus, making it the most robust and clinically important wave.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Evoked Potentials