[1] Sungkyunkwan Univ, Sch Med, Samsung Med Ctr, Dept Neurol, Seoul 135710, South Korea
[2] Sungkyunkwan Univ, Sch Med, Samsung Med Ctr, Dept Neurosurg, Seoul 135710, South Korea
[3] Soonchunhyang Univ, Coll Med, Dept Neurol, Seoul, South Korea
[4] Gyeongsang Natl Univ, Sch Med, Dept Neurol, Jinju, South Korea