1. Department of Neurology; Federation of National Public Service Personnel Mutual Aid Associations Toranomon Hospital; Tokyo Japan
2. Department of Neurology; University of Tokyo, Graduate School of Medicine; Tokyo Japan
3. Okinaka Memorial Institute for Medical Research; 2-2-2 Toranomon, Minato-ku Tokyo 105-8470 Japan
4. Department of Haematology; Federation of National Public Service Personnel Mutual Aid Associations, Toranomon Hospital; Tokyo Japan