EDT EDT EMG Waveform Analysis 2

Question 1

Myotonic discharges on needle EMG are characterized by:

Accepted Answer

Waxing and waning frequency and amplitude producing a dive-bomber sound

Answer

Myotonic discharges wax and wane in both frequency and amplitude, producing the classic 'dive-bomber' or revving motorcycle sound on the EMG speaker.

Question 2

In needle EMG, the term 'reduced recruitment' means:

Accepted Answer

Fewer motor units than expected are available to fire, reflecting motor unit loss

Answer

Reduced recruitment indicates fewer functioning motor units than expected for a given level of voluntary effort, a hallmark of neurogenic disease.

Question 3

End-plate noise seen on needle EMG is significant because:

Accepted Answer

It is a normal finding representing miniature end-plate potentials

Answer

End-plate noise consists of miniature end-plate potentials (MEPPs) and represents normal spontaneous ACh release at the neuromuscular junction, not pathology.

Question 4

A needle EMG finding of increased polyphasia (>20% polyphasic MUPs) in a muscle indicates:

Accepted Answer

Possible pathology suggesting reinnervation or myopathy causing desynchronized fiber firing

Answer

Increased polyphasia reflects desynchronized firing of muscle fibers within a motor unit, seen in both neurogenic (reinnervation) and myopathic conditions.

Question 5

Which EMG finding in paraspinal muscles supports a diagnosis of radiculopathy rather than plexopathy?

Accepted Answer

Fibrillations and PSWs in paraspinal muscles at the affected level

Answer

Paraspinal fibrillations at the appropriate spinal level support radiculopathy because the posterior primary ramus innervates paraspinal muscles proximal to the plexus.

(EDT) Electrodiagnostic Technician Certification Practice Test

(EDT) Electrodiagnostic Technician Certification Practice Test

EDT EDT EMG Waveform Analysis 2