1. Biomedical Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea
2. Department of Neurology, College of Medicine, Seoul National University, Seoul, Korea
3. Department of Neurology, Dizziness Center, Clinical Neuroscience Center, Seoul National University Bundang Hospital, Seongnam, Korea
4. Department of Neurology, Pusan National University Hospital, Pusan, Korea
5. Department of Neurology, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju, Korea
6. Department of Neurology, Chamjoeun Hospital, Gwangju-si, Korea
7. Department of Neurology, Daegu Catholic University College of Medicine, Daegu Catholic University Hospital, Daegu, Korea