[Evoked otoacoustic emissions in diagnosis of cochlear hearing disorders]

The authors consider the possibility of routine use of evoked otoacoustic emissions (EOE) in diagnosis of sensory hearing loss by comparison of EOE curves with relative curves obtained by pure tone audiometry. 180 ears with sensory hearing loss of different aetiologies were examined. EOE were obtained by application of Bray and Kemp's Evoked Otoacustic Measurement Package (ILO88). The results obtained show a close correlation between presence of EOE and real hearing losses of different frequencies obtained by pure tone audiometric evaluation. We could detect no EOE with hearing losses over 50 dB HL at 500 Hz, 40 dB HL at 1000 Hz, 50 dB HL at 2000 Hz and 85 dB HL at 4000 Hz. With a rate of middle hearing loss over 45 dB HL we also did not find EOE for the whole frequency range. On the base of this study, the authors conclude that EOE explore the functional integrity of those parts of the cochlea that correspond to the middle frequencies of hearing range. If EOE are not detectable, statements on the nature and extent of hearing loss on the base of this examination are not valid.