Frequency-specific electric response audiometry (ERA) and its clinical application in the diagnosis of hearing defects in the dog.

Abstract

Reference values were established for frequency-specific electric response audiometry (ERA) in dogs on the basis of the results of ERA examinations of 200 animals with normal hearing. Air-conducting acoustic tubes with foam stoppers were used in the determination of the following: the latencies of waves I, III and V; interpeak latencies (IPL) I-III, III-V and I-V; amplitudes I and V; and the amplitude difference I-V. A frequency-specific stimulus (tone pip) was used for frequency-specific examination (1 to 4 kHz) over the entire frequency range indicated. These reference values were then used for the clinical examination of 50 dogs with hearing defects. A frequency-specific ERA was conducted and the results evaluated. These findings made it possible to draw objective conclusions about the degree, type and site of the hearing defects. Frequency-specific electric response audiometry was shown to be an important diagnostic tool for the detection of partial high- and low-frequency hearing loss and for the characterisation of hearing defects of otological, otoneurological and neurological origin.