1. Biomedical Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea.
2. Department of Health Policy and Management, Seoul National University College of Medicine, Seoul, Korea.
3. Department of Family Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
4. Department of Family Medicine, College of Medicine, Seoul National University, Seoul, Korea.
5. Department of Neurology, College of Medicine, Seoul National University, Seoul, Korea.
6. Department of Neurology, Dizziness Center, Clinical Neuroscience Center, Seoul National University Bundang Hospital, Seongnam, Korea.