EEG Evoked Potentials 2

Question 1

A unilaterally prolonged P100 latency on visual evoked potential testing is most characteristically associated with which condition?

Accepted Answer

Demyelinating optic neuritis (multiple sclerosis)

Answer

Retinal detachment

Answer

Glaucoma

Answer

Cataracts

Question 2

In a BAEP recording, absent Wave I with relatively preserved Waves III and V most likely indicates pathology at which level?

Accepted Answer

Cochlea or cochlear nerve peripheral to the brainstem

Answer

Cochlear nucleus in the lower brainstem

Answer

Superior olivary complex

Answer

Inferior colliculus

Question 3

During intraoperative neurophysiological monitoring, a sudden 50% decrease in SSEP amplitude or a 10% increase in latency should prompt what immediate action?

Accepted Answer

Alert the surgical team immediately

Answer

Increase stimulus rate to improve signal averaging

Answer

Switch to a different stimulation site

Answer

Increase the number of averages collected

Question 4

What is the upper limit of normal for the interpeak latency I–V (IPL I–V) in BAEPs recorded from a typical adult?

Accepted Answer

Less than 4.4 ms

Answer

Less than 2.0 ms

Answer

Less than 3.0 ms

Answer

Less than 6.0 ms

Question 5

Bilateral prolongation of SSEP cortical latencies with normal peripheral nerve and plexus responses most strongly suggests pathology at which level?

Accepted Answer

Cervical spinal cord (myelopathy)

Answer

Bilateral peripheral neuropathy

Answer

Bilateral brachial plexopathy

Answer

Bilateral carpal tunnel syndrome

Question 6

The N20 component of the median nerve SSEP is primarily generated by which brain structure?

Accepted Answer

Primary somatosensory cortex (Area 3b, S1)

Answer

Thalamus (ventral posterior lateral nucleus)

Answer

Supplementary motor area

Answer

Parietal association cortex (Area 7)

Question 7

Which technical factor most directly degrades SSEP and BAEP signal quality by introducing 60 Hz noise and poor signal-to-noise ratio?

Accepted Answer

High electrode impedance

Answer

High patient body temperature

Answer

Slow stimulus repetition rate

Answer

Low number of trials averaged