1. Department of Neurology, College of Medicine, Chungbuk National University Hospital, Cheongju, Korea.
2. Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Korea.
3. Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
4. Department of Neurology, Ewha Woman's University, Seoul, Korea.
5. Department of Neurology, Seoul National University Hospital, Seoul, Korea.