[1] Seoul Natl Univ, Dept Neurol, Coll Med, 28 Yongon Dong, Seoul 110744, South Korea
[2] Seoul Natl Univ, Movement Disorder Ctr, Parkinson Study Grp, Seoul, South Korea
[3] Seoul Natl Univ, Neurosci Res Inst, Coll Med, Seoul, South Korea
[4] Seoul Natl Univ, Dept Radiol, Coll Med, 28 Yongon Dong, Seoul 110744, South Korea