[1] Catholic Univ Korea, Seoul St Marys Hosp, Coll Med, Dept Otolaryngol Head & Neck Surg, 222 Banpo Daero, Seoul 06591, South Korea
[2] Yonsei Univ, Wonju Coll Med, Res Inst Hearing Enhancement, Wonju, South Korea
[3] Yonsei Univ, Wonju Coll Med, Dept Otorhinolaryngol, Wonju, South Korea