1. Department of Diagnostic Medicine and
2. Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
3. Faculty of Pharmaceutical Sciences, University of Toyama, Toyama, Japan
4. Clinical Medicine Section, Department of Clinical Medicine, National Institute for Minamata Disease, Kumamoto, Japan
5. Department of Neurology and Rheumatology, Shinshu University School of Medicine, Matsumoto, Japan
6. Department of Medicine, Umeå University Hospital, Umeå, Sweden