1. Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
2. Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
3. Department of Neurology, Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
4. Department of Neurology, Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.