EDT EDT Special Populations & Considerations

Question 1

When performing nerve conduction studies in neonates and infants, conduction velocities are expected to be:

Accepted Answer

Approximately half of adult values, reaching adult levels by age 3–5 years

Answer

Similar to adult values due to full myelination at birth

Answer

Faster than adult values due to smaller nerve diameter

Answer

Highly variable and cannot be interpreted

Question 2

In elderly patients, age-related changes in NCS include:

Accepted Answer

Reduced SNAP amplitudes, slightly slowed conduction velocities, and prolonged distal latencies

Answer

Increased SNAP amplitudes and faster conduction velocities

Answer

Absent CMAP responses bilaterally

Answer

Markedly prolonged F-wave latencies with normal distal latencies

Question 3

Which safety precaution is essential before performing nerve conduction studies in a patient with an implanted cardiac pacemaker?

Accepted Answer

Consult with cardiology and avoid stimulation over the chest or neck; keep currents distal and away from the pacemaker leads

Answer

Pacemaker patients cannot have NCS under any circumstances

Answer

Only perform sensory NCS and avoid all motor studies

Answer

Increase stimulus intensity to achieve supramaximal stimulation quickly

Question 4

In patients with lymphedema following mastectomy, EDX of the ipsilateral upper extremity requires caution because:

Accepted Answer

There is risk of introducing infection or worsening lymphedema with needle insertion; surface techniques are preferred

Answer

NCS results will always show false-positive demyelination

Answer

Conduction velocities are always faster in lymphedematous limbs

Answer

All NCS responses will be absent

Question 5

EDX studies in pediatric patients may require sedation because:

Accepted Answer

Movement and poor cooperation can produce artifact and make needle EMG technically unreliable

Answer

Nerve conduction velocities cannot be measured without sedation

Answer

Sedation increases SNAP amplitudes in children

Answer

Pediatric patients have absolute contraindications to awake NCS

Question 6

In patients receiving anticoagulation therapy (e.g., warfarin), the primary concern with needle EMG is:

Accepted Answer

Risk of bleeding, hematoma, or compartment syndrome, particularly in deep muscles

Answer

Altered nerve conduction velocities due to medication

Answer

Complete inability to perform the study

Answer

Electrical interference from the medication