[A case of idiopathic propriospinal myoclonus accompanied by giant somatosensory evoked potential].

A 41-year-old man visited our clinic because of headache with fever, suggestive of aseptic meningitis. His headache improved in a few days. His neurological examination showed positive jolt accentuation and myoclonus of the thoracoabdominal muscles extending to extremities upon patellar tapping.