1. Department of Neurology, Ewha Womans University School of Medicine, Seoul, Korea.
2. Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Pediatrics, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
5. Department of Neurology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Department of Neurology, Research Institute and Hospital of National Cancer Center, Goyang, Korea.