We present a 77-year-old woman with myoclonus and epilepsy. She was well until 35 years of age, when she noted an onset of trembling of the legs upon standing. Her symptom slowly progressed, and she felt a difficulty in standing when she was 39-year-old. She had a major motor seizure without an apparent focal onset when she was 46-year-old. She also developed tremor in her hands, and she felt difficulty in holding a glass filled with water. She was admitted to our service for the first time in 1965 when she was 51-year-old. She showed wide-based ataxic gait with truncal titubation. In finger to nose test, myoclonic jerks were induced in the upper extremities. Otherwise neurological examination was unremarkable. She was treated with primidone and phenobarbital, and was discharged for out patient follow up. Her symptoms slowly progressed, and gait and station became more difficult. Mentally she was sound. Three months prior to the present admission, she developed more difficulty in gait, and decrease in food intake. On the 14th of September in 1991, she was seen by a local physician who found an abnormal shadow in her chest X-ray, and she was admitted to our service for further work-up on September 18, 1991. On admission, the patient was a chronically ill and emaciated woman. Her blood pressure was 140/84 mmHg, heart rate 115/minutes and regular, and the body temperature 36.9 degrees C. The palpebral conjunctivae were anemic. No cervical adenopathy was noted. The lung fields were clear, and no heart murmur was audible. The abdomen was soft, and no organomegaly was present. On neurologic examination, she looked somnolent with disorientation to time and place. Her memory was poor, and she could not do well serial 7s. The disc was flat and the ocular movements appeared intact. Other cranial nerves were also unremarkable. She showed diffuse muscle wasting. She was unable to stand or walk. Maintaining the sitting position was also difficult. She was able to raise her arms, but almost unable to move her lower extremities. The precise muscle testing was impossible. No abnormal involuntary movement was seen. Finger to nose test could not be performed.(ABSTRACT TRUNCATED AT 400 WORDS)