Hearing in the dog as assessed by auditory brainstem evoked potentials.

Auditory brainstem evoked potentials were used to test hearing in dogs. A technique is described which can be carried out normally on conscious or sedated animals. Eleven normal adults, eight normal puppies and four deaf animals were rested. Reproducible brainstem evoked potentials were readily obtained from the normal adult dogs except when they became fractious (unsedated animals only). Usually the evoked waveform consisted of four peaks (I to IV) occurring in the first five milliseconds after the delivery of an auditory stimulus. In adults, the brainstem threshold for clicks varied between 5 and 25 dB normal hearing level. Brainstem evoked potentials were not detected in puppies at two weeks old but occurred at three weeks old. Between three and seven weeks of age the latencies of waves I and IV and the interval between these waves became shorter, to resemble the adult waveform. No brainstem evoked potentials were detected in the four deaf animals.