EDT EDX Testing Techniques 2

Question 1

When performing median motor nerve conduction studies, the active (G1) electrode is placed over which landmark?

Accepted Answer

Abductor pollicis brevis muscle belly

Answer

The G1 electrode is placed over the belly of the abductor pollicis brevis (APB) to record the compound muscle action potential for median motor studies.

Question 2

Which filter setting change would most reduce high-frequency artifact during EMG needle examination?

Accepted Answer

Lower the high-frequency filter from 10 kHz to 2 kHz

Answer

Lowering the high-frequency (low-pass) filter reduces high-frequency noise and artifact while preserving the essential components of motor unit potentials.

Question 3

An H-reflex is most reliably elicited in adults by stimulating which nerve?

Accepted Answer

Tibial nerve at the popliteal fossa

Answer

The H-reflex is most consistently recorded from the soleus/gastrocnemius by stimulating the tibial nerve in the popliteal fossa with long-duration, low-intensity stimuli.

Question 4

What is the primary purpose of applying a ground electrode during nerve conduction studies?

Accepted Answer

Reduce common-mode electrical noise and improve signal quality

Answer

The ground electrode provides a reference point that helps the differential amplifier cancel out common-mode interference, reducing electrical noise in the recording.

Question 5

During repetitive nerve stimulation (RNS) at 3 Hz, a decrement greater than what percentage is considered abnormal?

Accepted Answer

10%

Answer

A decrement exceeding 10% in CMAP amplitude from the first to the fourth or fifth response during 3 Hz RNS is considered abnormal and suggests a neuromuscular junction disorder.

(EDT) Electrodiagnostic Technician Certification Practice Test

(EDT) Electrodiagnostic Technician Certification Practice Test

EDT EDX Testing Techniques 2