1. Department of Neurology, Seoul National University Hospital, Seoul, Korea.
2. Department of Neurology, School of Medicine, Kyungpook National University, Kyungpook National University Chilgok Hospital, Daegu, Korea.
3. Brain Science and Engineering Institute, Kyungpook National University, Daegu, Korea.
4. Department of Neurosurgery, Seoul National University Hospital, Seoul, Korea.