1. Department of Neurology, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
2. Department of Medicine, Graduate School, Kyung Hee University, Seoul, Korea.
3. Department of Neurology, Kyung Hee University Hospital, Seoul, Korea.
4. Department of Neurology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea.