[Transitory evoked otoacoustic emissions in patients with cerebellopontile angle tumors]

Click-evoked transitory otoacoustic emissions (TEOAE) were recorded in 34 patients suspected of having an acoustic neuroma with consequent hearing loss. Measurements took place one day prior to transtemporal removal of tumor. The evoked otoacoustic emissions were compared to hearing thresholds of the pure-tone audiogram. In 31 of the 34 patients tested, the spectrum of the emissions corresponded to the audiogram, in that an emission was not detectable at frequencies with a hearing loss exceeding 30 dB HL. Three patients showed good emissions in spite of a demonstrable hearing loss. This can be expected when only retrocochlear lesions are present. These results suggest that in most cases the hearing loss accompanying a retrocochlear process is combined with secondary lesions of the cochlea and is rarely due to isolated retrocochlear malfunction.