**2. Materials and methods**

#### **2.1 Patients and eligibility**

We reviewed the medical records of ISSHL patients who visited 'Tinnitus & Hearing loss clinic' in Kyung Hee Oriental Medical Hospital, Seoul, Korea from June 2006 to February 2011. Patients who met the definition of ISSHL, which is defined as an abrupt or rapidly progressing hearing loss of at least 25 dB in 3 contiguous frequencies over a period of no more than 3 days, were eligible to participate in this study. We excluded patients with sensorineural hearing loss caused by trauma, noise, tumors, otitis media or Meniere's disease. Additionally, patients were ineligible if they have hearing loss in both ears.

Of a total 117 patients, ten had Meniere's disease, two had senile progressive hearing loss, four had hearing loss in both ears, one had otitis media and twenty-eight failed to undergo a follow up audiogram. Therefore, 72 patients (40 males, 32 females) were enrolled in this study (Fig. 1). This study was approved by the Institutional Review Board of Kyung Hee Oriental Medical Hospital (KOMCIRB-2011-09).

Fig. 1. Flow chart of the study
