ABEM Evoked Potentials & Late Response Studies

Question 1

The H-reflex is most commonly elicited from which nerve-muscle combination?

Accepted Answer

Tibial nerve - soleus

Answer

Median nerve - flexor carpi radialis

Answer

Peroneal nerve - tibialis anterior

Answer

Ulnar nerve - abductor digiti minimi

Question 2

Which of the following best describes the physiological basis of F-waves?

Accepted Answer

Late motor responses due to antidromic activation of motor neurons followed by orthodromic discharge

Answer

Sensory nerve action potentials recorded from proximal muscles

Answer

Direct muscle responses to submaximal nerve stimulation

Answer

Reflexes mediated through the dorsal root ganglion synapse

Question 3

What does prolonged F-wave latency most commonly indicate in electrodiagnostic studies?

Accepted Answer

Proximal motor nerve demyelination or radiculopathy

Answer

Distal sensory nerve pathology

Answer

Neuromuscular junction dysfunction

Answer

Anterior horn cell disease exclusively

Question 4

H-reflex latency in adults is most significantly influenced by which factor?

Accepted Answer

Limb length and patient height

Answer

Age and body temperature

Answer

Muscle mass and body weight

Answer

Stimulus frequency and repetition rate

Question 5

Bilateral absent H-reflexes at rest in an adult most strongly suggests which diagnosis?

Accepted Answer

Diffuse peripheral neuropathy

Answer

Bilateral carpal tunnel syndrome

Answer

Unilateral S1 radiculopathy

Answer

Bilateral cubital tunnel syndrome

Question 6

What stimulus rate is most appropriate for eliciting F-waves during a nerve conduction study?

Accepted Answer

0.5-1 Hz

Answer

3-5 Hz

Answer

10-20 Hz

Answer

30-50 Hz

Question 7

In F-wave analysis, 'F-wave persistence' refers to which measurement?

Accepted Answer

The percentage of stimuli that successfully elicit an F-wave response

Answer

The amplitude of F-waves relative to the M-wave amplitude

Answer

The minimum F-wave latency recorded across 10-20 trials

Answer

The duration of the F-wave waveform in milliseconds