EMG Instrumentation & Data Interpretation

Question 1

What is the function of an amplifier in EMG instrumentation?

Accepted Answer

Amplifies muscle electrical activity

Answer

The amplifier boosts the tiny electrical signals from muscles so they can be displayed and analyzed accurately.

Question 2

Which setting affects the frequency range displayed in an EMG reading?

Accepted Answer

Filter settings

Answer

Filter settings adjust the frequency range shown, helping isolate relevant signals while minimizing noise.

Question 3

What does a polyphasic motor unit potential indicate?

Accepted Answer

Reinnervation or neuromuscular disorder

Answer

Polyphasic potentials often reflect reinnervation or immature neuromuscular units, typically seen in recovering or diseased muscle.

Question 4

What does the sweep speed control in EMG equipment?

Accepted Answer

Time resolution of waveform display

Answer

Sweep speed determines how fast waveforms move across the screen, affecting time resolution of the recording.

Question 5

How does improper grounding affect EMG signals?

Accepted Answer

Introduces signal noise and interference

Answer

Poor grounding increases electrical noise and can interfere with accurate signal recording and interpretation.

(EMG) Electromyography Certification Practice Test