목적: To evaluate the influence of cochlear dead regions (DRs) detected by threshold- equalizing noise (TEN) test on the recovery after idiopathic sudden sensorineural hearing loss (ISSNHL). 방법:52 consecutive patients with ISSNHL were prospectively enrolled. All patients were treated with methylprednisolone for 10 days (48 mg/d for 4 days, followed by a taper of 8 mg every 2 days). Pure-tone audiometry and TEN test was performed to assess hearing level and recovery. Audiological profiles, final recovery were compared according to presence of DRs. 결과:Of the patients, 36.5% (n=19) had a DR at initial evaluation. Patients with DR exhibited distinctive characteristics, including older age, accompanying diabetes and hypertension, presence of dizziness, worse initial hearing and contralateral hearing. Logistic regression analysis revealed that presence of DR decreased the possibility of recovery by 3.968-fold (95% CI 1.139-13.889). Complete recovery under 25 dB was associated with initial hearing level alone (OR 0.935, 95% CI 0.897-0.974) 결론:ISSNHL patients with DR are associated with poor recovery. TEN test seems to be a reliable tool for prediction of recovery in patients with ISSNHL.