1. Department of Neurology, National Hospital Organization, Sendai Nishitaga Hospital, 2-11-11 Kagitorihoncho, Sendai Taihaku-ku, Miyagi 982-8555, Japan
2. Department of Cognitive and Motor Aging, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Sendai Aoba-ku, Miyagi 980-8575, Japan
3. Department of Neurology, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
4. Department of Neurology, Saiseikai Imabari Center for Health and Welfare, 7-61 Kitamura, Imabari, Ehime 799-1592, Japan
5. Department of Neurology, Osaka University Graduate School of Medicine, 2-15 Yamadaoka, Suita, Osaka 565-0871, Japan
6. Department of Neurology, Juntendo University School of Medicine, 2-1-1 Bunkyo-ku, Tokyo 113-8421, Japan