EDT Device Setup & Operation 3

Question 1

When calibrating an EMG machine before use, which parameter confirms that the amplifier gain is accurate?

Accepted Answer

A known calibration signal produces the expected deflection height on screen

Answer

Applying a known calibration pulse and verifying the waveform height confirms that the amplifier gain is set correctly.

Question 2

Which stimulator parameter controls how long the electrical impulse is applied to the nerve during a nerve conduction study?

Accepted Answer

Pulse duration (µs)

Answer

Pulse duration (typically 0.1–0.2 ms for motor studies) determines the width of the stimulus waveform delivered to the nerve.

Question 3

An EMG technician is performing a needle exam and observes a signal that appears to be cut off at the top of the screen. What is the correct adjustment?

Accepted Answer

Decrease sensitivity (increase mV/div)

Answer

Decreasing sensitivity (larger mV/div value) expands the vertical scale so tall signals fit within the display window without clipping.

Question 4

For H-reflex recordings in adults, the active electrode is typically placed over which muscle?

Accepted Answer

Soleus (medial gastrocnemius)

Answer

The H-reflex in adults is most reliably recorded from the soleus/medial gastrocnemius via tibial nerve stimulation at the popliteal fossa.

Question 5

What is the recommended inter-electrode distance between E1 and E2 for sensory nerve conduction studies using ring electrodes on a finger?

Accepted Answer

3–4 cm

Answer

Ring electrodes on adjacent finger segments are placed approximately 3–4 cm apart to ensure adequate signal separation.

(EDT) Electrodiagnostic Technician Certification Practice Test

(EDT) Electrodiagnostic Technician Certification Practice Test

EDT Device Setup & Operation 3