[A case of chronic inflammatory demyelinating polyradiculoneuropathy with nocturnal myoclonus].

A 43-year-old man began to notice progressive tingling sensation in his legs and unsteadiness in walking in 1983. His symptoms diminished with prednisolone treatment. In 1986, the same symptoms developed again and abated with prednisolone and plasmapheresis. In 1988 he was admitted because of progression of the symptoms in the legs. Neurological examinations showed mild muscle atrophy and weakness in the legs, loss of the deep reflexes, and impairment of cutaneous and deep sensation of the extremities. Heel-knee test was unsteady, and his gait was wide-based. In addition, Babinski and Chaddock signs were positive bilaterally. He had spontaneous myoclonic jerks of his legs, so-called "tonic triple flexion". These jerks were particularly evident during sleep, and were considered to be "nocturnal myoclonus". The same jerks were provoked by painful stimuli or Babinski's, Marie-Foix's maneuver. These jerks were considered to be so-called "spinal automatism" of spinal or brainstem origin. The latencies of VEP on both sides were prolonged and ABR showed abnormalities indicative of brainstem lesion. There were no abnormalities in cranial and spinal MRI. Our case was proven to have central nervus system lesions in addition to findings of chronic inflammatory demyelinating polyradiculoneuropathy.