TEOAEs in Acoustic Neuroma Patients

Abstract

Transient evoked otoacoustic emissions (TEOAEs) reflect the cochlear micromechanics related to the active motile property of outer hair cells. Thus, it may be hypothesized that if hearing impairments is neural origin, normal TEOAEs can be obtained from the cochlea.
In the present study, we recorded TEOAEs in 95 acoustic neuroma patients and 50 Meniere's disease patients in order to clarify the relationship between the hearing level and TEOAEs in cochlear and retrocochlear hearing impairments.
Mean hearing level of the acoustic neuroma patients in whom TEOAEs were obtained was 28.4±14.6dB and that of the Meniere's disease patients was 28.3±12.5dB. Although there were 3 acoustic neuroma patients with TEOAE in spite of hearing impaiment over 60dB, deterioration in TEP, one of the TEOAE parameters was found comparing with healthy side ear. From these results, we concluded that there must be an affection to the cochlea in almost all acoustic neuroma patients. Thus, the normal TEOAEs could uncommonly be found in acoustic neuroma patients with moderate or severe hearing impairment.