1. Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
2. Department of Gastroenterology and Hepatology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
3. Department of Radiology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
4. Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan