Spinal myoclonus with giant somatosensory evoked potentials and enhanced long-loop reflex: a case report.

We describe a patient with an ischaemic lesion of the cervical spinal cord who presented with clinical evidence of stimulus-sensitive, multisegmental myoclonic jerks restricted to the truncal and proximal limb muscles and accompanied by electrophysiological features (giant somatosensory evoked potentials and enhanced long-loop reflex) of cortical myoclonus. We hypothesize that these features might result from a loss of inhibitory influences on the sensory input to cortical structures: a concomitant contribution of spinal and cortical hyperexcitability seems to have played a crucial role in inducing myoclonus in our patient.