Department of Neurology, Seoul National University College of Medicine and Seoul National University Hospital, Seoul, South Korea. Department of Neurology, Seoul National University College of Medicine and Seoul Metropolitan Government-Seoul National University Boramae Medical Center, 20 Boramae-ro 5-gil, Dongjak-Gu, Seoul, 07061, South Korea. hmkwon@snu.ac.kr. Department of Family Medicine, Seoul National University College of Medicine and Seoul National University Hospital, 101 Daehak-ro, Jongno-Gu, Seoul, 03080, South Korea. pjhn@snu.ac.kr. Department of Family Medicine, Seoul National University College of Medicine and Seoul National University Hospital, 101 Daehak-ro, Jongno-Gu, Seoul, 03080, South Korea. Department of Family Medicine, Seoul National University College of Medicine and Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, South Korea.