1. Department of Neurology, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea.
2. Social and Preventive Medicine, Hallym University College of Medicine, Chuncheon, Korea.
3. Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Korea.
4. Department of Biostatistics, College of Medicine, Korea University, Seoul, Korea.
5. Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
6. Department of Neurology, Eulji General Hospital, Eulji University School of Medicine, Seoul, Korea.
7. Department of Neurology, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.
8. Department of Neurology, Hallym University Sacred Heart Hospital, Anyang, Korea.