Vol.98No.11contentsPRACTICA OTO-RHINO-LARYNGOLOGICA
Vol. 98 No. 11 November 2005
Auditory Neuropathy: Clinical Concept,
Audiological Features and Managements
Tetsuya Tono
(University of the Ryukyus)
Auditory neuropathy (AN) is characterized by preservation of cochlear outer hair cell function, as evidenced by the presence of otoacoustic emissions and/or measurable cochlear microphonics, when the ABR is absent. Possible sites of AN are the inner hair cells, the auditory nerve and synaptic juncture between inner hair cells and the dendritic processes of the spiral ganglion cells. Thus hearing loss in AN may not be clearly categorized as cochlear or retrocochlear deafness using the currently available auditory testing methods. AN is found in patients ranging in age from infants to adults and can be clinically classified into two types, postlingual (adult) and the prelingual (infant) types, according to the age of onset. Two typical AN cases from each type are presented to discuss appropriate clinical management including cochlear implants for these patients. Despite increasing evidence from overseas showing the potential benefit of cochlear implants in prelingual-type AN, caution should be exercised when considering cochlear implantation in the postlingual type. Promontory stimulation test is thought to be useful in order for predicting postoperative performance with cochlear implants in adult patients.
Key words : Auditory neuropathy, otoacoustic emissions, auditory brain stem response (ABR), cochlear implant, promontory stimulation test