1. Department of Neurology, Hallym University College of Medicine, Chuncheon, Korea.
2. Department of Neurology, Chung-Ang University Medical Center, Chung-Ang University, College of Medicine, Seoul, Korea.
3. Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.