[1] Keimyung Univ, Dongsan Hosp, Dept Neurol, Sch Med, 1095 Dalgubeol Daero, Daegu 42601, South Korea
[2] Seoul Natl Univ, Bundang Hosp, Dept Neurol, Sch Med, Seongnam, South Korea
[3] Univ Texas Hlth Sci Ctr Houston, McGovern Med Sch, Dept Neurol & Neurosurg, Houston, TX 77030 USA