[1] Yonsei Univ, Coll Med, Neurol, Seoul, South Korea
[2] Gacheon Univ, Neurol, Inchon, South Korea
[3] Severance Hosp, Clin Trials Ctr, Seoul, South Korea
[4] Hallym Univ, Neurol, Pyongchon, South Korea
[5] Seoul Natl Univ, Neurol, Seoul, South Korea
[6] Univ Ulsan, Neurol, Seoul, South Korea