Clinical applications of otoacoustic emissions in sudden hearing loss

Sudden hearing loss (SHL) is a controversial topic for which no definitive practical guidelines exist. Studies employing vasodilators, plasma expanders, anticoagulants, and carbogen inhalations have shown no improvement over the rate of spontaneous recovery. At present, there is insufficient evidence to support medical treatment for SHL, except steroid therapy in selected patients. Distortion product otoacoustic emissions (DPOAEs) are sensitive to cochlear disorders and are absent in ischemic injury to the cochlea, but can persist in cochlear neuritis. In a prospective study of 10 patients who presented to Albany Medical Center from 1995 to 1996, three patients with intact DPOAEs at presentation had an average improvement of 33 dB in the pure-tone average (PTA) of 0.5, 1.0, and 2.0 kHz with steroid therapy, whereas five of seven patients with absent DPOAEs had no improvement in hearing despite steroid therapy in six patients. The presence of DPOAEs may be a useful prognostic factor that positively correlates with recovery from SHL.