EDT EDT Clinical Correlations & Pathology

Question 1

Which EDX pattern is most consistent with a diagnosis of Guillain-Barré syndrome (acute inflammatory demyelinating polyneuropathy)?

Accepted Answer

Diffuse demyelination with prolonged distal latencies, slow conduction velocities, and absent F-waves

Answer

Axonal loss with active denervation on EMG

Answer

Length-dependent axonal polyneuropathy with distal sensory loss

Answer

Normal NCS with myopathic EMG

Question 2

In diabetic polyneuropathy, the typical EDX pattern is:

Accepted Answer

Length-dependent axonal sensorimotor polyneuropathy with earliest changes in distal lower extremity sensory nerves

Answer

Multifocal demyelinating neuropathy sparing sensory nerves

Answer

Proximal motor neuropathy with normal sensory NCS

Answer

Focal conduction block at common compression sites only

Question 3

EDX findings in radial nerve palsy due to 'Saturday night palsy' (compression at the spiral groove) typically show:

Accepted Answer

Conduction block or axonal loss across the spiral groove sparing radial muscles proximal to the groove

Answer

Normal motor NCS to all radial-innervated muscles

Answer

Absent median and ulnar sensory responses

Answer

Diffuse demyelinating polyneuropathy

Question 4

In a patient with peroneal nerve palsy at the fibular head, needle EMG of which muscle would help differentiate it from L5 radiculopathy?

Accepted Answer

Short head of the biceps femoris

Answer

Tibialis anterior

Answer

Extensor hallucis longus

Answer

Peroneus longus

Question 5

Which EDX finding best differentiates cervical radiculopathy from brachial plexopathy?

Accepted Answer

Abnormal needle EMG in paraspinal muscles at the affected spinal level

Answer

Reduced SNAP amplitude in the distribution of the affected root

Answer

Prolonged F-wave latencies in the affected limb

Answer

Reduced CMAP amplitude in the affected muscles

Question 6

EDX evaluation of multifocal motor neuropathy (MMN) characteristically reveals:

Accepted Answer

Multiple sites of persistent motor conduction block without sensory abnormalities

Answer

Symmetric axonal polyneuropathy with sensory predominance

Answer

Diffuse demyelination with sensory involvement

Answer

Normal NCS with myopathic EMG