1. Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Neuro-Radiology, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.