[1] Seoul Natl Univ, Bundang Hosp, Dept Neurol, Coll Med, Songnam, South Korea
[2] Johns Hopkins Univ Hosp, Dept Neurol, Sch Med, Baltimore, MD 21287 USA
[3] Johns Hopkins Univ Hosp, Dept Otolaryngol Head & Neck Surg, Sch Med, Baltimore, MD 21287 USA
[4] Johns Hopkins Univ Hosp, Dept Neurosci, Sch Med, Baltimore, MD 21287 USA
[5] Johns Hopkins Univ Hosp, Dept Ophthalmol, Sch Med, Baltimore, MD 21287 USA