1. Department of Neurology, Obihiro Kosei General Hospital, Japan
2. Department of Neurology, Japanese Red Cross Asahikawa Hospital, Japan
3. Department of Neurology, National Hospital Organization Hokkaido Medical Center, Japan
4. Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Japan
5. Department of Neurology, Hakodate Municipal Hospital, Japan