1. Department of Neurology, Institute of Neuroscience Center, Samsung Medical Center, Seoul, Korea
2. Physiologic Diagnostic Laboratory, Seoul National University Bundang Hospital, Seongnam, Korea
3. Department of Neurosurgery, Ajou University Hospital, Suwon, Korea
4. Department of Neurology, Asan Medical Center, Seoul, Korea
5. Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea