aDizziness Center, Seoul National University Bundang Hospital, Seongnam

bDepartment of Neurology, Seoul National University College of Medicine, Seoul

cDepartment of Neurology, Soonchunhang University Bucheon Hospital, Bucheon, Korea

Correspondence to Ji-Soo Kim, MD, PhD, Dizziness Center, Seoul National University Bundang Hospital, Department of Neurology, Seoul National University College of Medicine, 173-82 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 46918, Korea. Tel: +82 31 787 7463; e-mail: [email protected]