1. Department of Neurology, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, Republic of Korea
2. Department of Neurology, School of Medicine, Kyungpook National University Chilgok Hospital, Daegu, Republic of Korea
3. Division of Hematology/Oncology, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, Republic of Korea
4. Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA