A patient has irregular stimulus-sensitive distal upper-limb jerks. Surface EMG bursts are brief, but routine EEG shows no obvious spike before

Question

A patient has irregular stimulus-sensitive distal upper-limb jerks. Surface EMG bursts are brief, but routine EEG shows no obvious spike before individual jerks. Which paired neurophysiological finding would most strongly support cortical myoclonus?

Accepted Answer

A pre-jerk cortical potential on back-averaging with giant somatosensory evoked potentials

Answer

Continuous motor-unit activity at rest with preserved sensory evoked potentials and normal back-averaging

Answer

Neuromyotonic doublet discharges with absent sensory nerve action potentials and normal evoked responses

Answer

A 13–18 Hz coherent leg tremor while standing with normal cortical back-averaging

Answer

A Bereitschaftspotential preceding variable axial jerks with prolonged and inconsistent EMG bursts

Convulsive status epilepticus — SCE Neurology MCQ

A patient has irregular stimulus-sensitive distal upper-limb jerks. Surface EMG bursts are brief, but routine EEG shows no obvious spike before individual jerks. Which paired neurophysiological finding would most strongly support cortical myoclonus?