Abstract
We investigated the predictive value of distortion product otoacoustic emissions (DPOAEs) for the hearing prognosis of idiopathic sudden sensorineural hearing loss (ISSNHL). Seventy-eight patients with ISSNHL (time from the onset to the start of treatment ≤14 days) were enrolled in the study. They received steroid administration (400 mg/day of hydrocortisone sodium succinate followed by tapered doses) combined with hyperbaric oxygen therapy. DPOAEs (f2/f1 = 1.2, L1 = 80 dBSPL, L2 = 70 dBSPL, f2 = 593-6031 Hz, every one-third octave) were measured before treatment. The hearing improvement rate was calculated as percentage of recovery compared to the hearing of the contralateral ear. Five potential prognostic factors (DPOAEs, patient's age, days from onset to treatment, presence of vertigo, and initial hearing level) and hearing outcomes were examined by simple regression and multiple logistic regression analyses. DPOAEs in the high-frequency range (f2=3031Hz, 4812Hz) significantly correlated with the hearing improvement rate by multiple logistic regression analyses, but did not with patient's age, days from onset to treatment, presence of vertigo, or initial hearing level. After adjusting for the latter four confounding factors, high DPOAE outputs still significantly related to good hearing recovery by multiple logistic regression analyses. These results suggested that the DPOAE outputs in the high-frequency range before treatment can be a useful predictive indicator of hearing outcomes in patients with ISSNHL.
