Transiently evoked otoacoustic emissions as a prognostic indicator in idiopathic sudden hearing loss

Idiopathic sudden sensorineural hearing loss (ISHL) remains a controversial topic. So far, there are no proven objective auditory factors to establish prognosis. Otoacoustic emissions reflect the functional integrity of the outer hair cells. The aim of this study was to assess the presence of transiently evoked otoacoustic emissions (TEOAEs) in the early stages of ISHL cases as a prognostic indicator. Thirty patients hospitalized for ISHL were included in the study. All patients underwent pure-tone audiometry (PTA) and TEOAE recordings on the admission day and at least three measures on the subsequent eight days. The audiometric threshold improvement at each frequency was correlated with the TEOAE parameters on each measure. Finally, the presence of TEOAEs on early examination was correlated with PTA threshold improvement. Twenty-three out of 30 patients experienced hearing recovery. Fourteen of the recovered patients had recordable TEOAEs or acceptable TEOAE peak amplitudes in some frequency bands on the first two measures, despite having audiometric thresholds greater than 40 dB HL. It thus seems that TEOAEs might serve as a clinical tool for prediction of recovery in ISHL cases.