1. Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Gangnam-gu, Seoul, Korea
2. Department of Neurology, Chungnam National University Hospital, Jung-gu, Daejeon, Korea
3. Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Gangnam-gu, Seoul, Korea
4. Department of Biomedical Engineering, Hanyang University, Seongdong-gu, Seoul, Korea
5. Department of Neurology, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon-si, Gangwon-do, Korea
6. Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Gangnam-gu, Seoul, Korea
7. Department of Internal Medicine, Division of Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA