[1] Korea Univ, Med Ctr, Dept Neurol, Seoul, South Korea
[2] Korea Univ, Dept Otorhinolaryngol Head & Neck Surg, Coll Med, Seoul, South Korea
[3] Korea Univ, Med Ctr, Seoul, South Korea
[4] Korea Univ, Anam Hosp, Dept Radiol, Seoul, South Korea
[5] Korea Univ, BK21 FOUR Program Learning Hlth Syst, Seoul, South Korea
[6] Seoul Natl Univ, Clin Neurosci Ctr, Bundang Hosp, Seoul, South Korea
[7] Seoul Natl Univ, Dept Neurol, Coll Med, Seoul, South Korea