EMG EMG Clinical Applications & Pathology

Question 1

Which EMG finding is most characteristic of amyotrophic lateral sclerosis (ALS)?

Accepted Answer

Widespread active denervation with fasciculation potentials in multiple limbs and the tongue

Answer

ALS produces widespread active denervation (fibrillations, fasciculations) across multiple body regions including bulbar muscles, reflecting both upper and lower motor neuron involvement.

Question 2

In carpal tunnel syndrome, which nerve conduction finding is typically the earliest and most sensitive indicator?

Accepted Answer

Prolonged median sensory peak latency across the wrist

Answer

Prolonged median sensory peak latency across the wrist segment is the earliest and most sensitive electrodiagnostic finding in carpal tunnel syndrome.

Question 3

What pattern of abnormality on nerve conduction studies is most consistent with Guillain-Barré syndrome (AIDP subtype)?

Accepted Answer

Prolonged distal latencies, slowed conduction velocities, conduction block, and temporal dispersion

Answer

AIDP (the most common GBS subtype in the US) is a demyelinating neuropathy characterized by prolonged distal latencies, slow conduction velocities, conduction block, and temporal dispersion.

Question 4

Which myopathy typically shows short-duration, low-amplitude, polyphasic motor unit potentials (MUPs) with early recruitment on needle EMG?

Accepted Answer

Inflammatory myopathy such as polymyositis

Answer

Inflammatory myopathies such as polymyositis produce myopathic MUPs (short duration, low amplitude, polyphasic) with early recruitment due to loss of individual muscle fibers.

Question 5

A patient with bilateral foot drop, absent ankle reflexes, and stocking-glove sensory loss most likely has which electrodiagnostic pattern?

Accepted Answer

Length-dependent polyneuropathy with distal sensorimotor involvement

Answer

Stocking-glove distribution with absent ankle reflexes is the hallmark of length-dependent polyneuropathy, where the longest nerve fibers are affected first.

(EMG) Electromyography Certification Practice Test

(EMG) Electromyography Certification Practice Test

EMG EMG Clinical Applications & Pathology