An animal model of auditory neuropathy.
OBJECTIVE
We describe an animal model of auditory neuropathy in which subjects have extensive, scattered inner haircell loss but with a relatively intact outer haircell population.


METHODS
Such a pattern of cochlear haircell damage can be produced in the chinchilla by treatment with the anticancer agent carboplatin.


RESULTS
In these subjects, otoacoustic emissions (OAEs) and cochlear microphonics remain normal while auditory brain stem evoked potential (ABR) thresholds are significantly elevated. However, in the same subjects, central auditory neurons (in the inferior colliculus) have response thresholds that are considerably lower (by up to 50 dB) than ABR thresholds. These findings parallel the characteristics of auditory neuropathy in humans, in which absent or abnormal ABRs are recorded in patients with only mild to moderate audiometric thresholds and preserved OAEs.


CONCLUSIONS
We suggest that scattered inner haircell lesions also can result from long-term cochlear hypoxia, and we propose that this is a likely candidate for the etiology of many types of auditory neuropathy in human subjects.
Harrison
R V
RV
Department of Otolaryngology, University of Toronto and The Hospital For Sick Children, Ontario, Canada.
D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects; D001309:Auditory Threshold; D016190:Carboplatin / Q000009:adverse effects; D002682:Chinchilla; D015834:Cochlear Diseases / Q000209:etiology / Q000473:pathology; D016057:Evoked Potentials, Auditory, Brain Stem; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects / Q000473:pathology*; D000860:Hypoxia / Q000139:chemically induced / Q000150:complications; D013997:Time Factors
D000970:Antineoplastic Agents; D016190:Carboplatin