The Effect of Chronic Otitis Externa - Media on Brainstem Auditory Evoked Response in Dogs
The objective of the study was to present normative Brainstem Auditory Evoked Response's (BAER) data acquired by the both air conducted clicks (30-100 dBHL) and bone conducted clicks (100-130 dBHL) for normal dogs, and dogs with chronic otitis externa-media. The data were analyzed to acquire reference values of the laboratory in 55 healthy dogs and to estimate the degree of hearing impairment associated with the disease. Fifty four dogs with chronic otitis externa-media were divided into two groups. The first group included dogs with severe chronic otitis externa-media, candidate to surgery (n=16), and the second group included dogs with mild chronic otitis externa-media, candidate to medical treatment (n=38). The appearance rate of V potential was found higher than the others at the every stimulation level. Seventh potential was not seen by the bone conducted click at the all stimulation level, and also in cases with severe chronic otitis externa-media by the air conducted click. While fifth potential was seen more than 50 % at the 60 dBHL in severe otitis externa-media, it was at the 30 dBHL in mild otitis externa. The latencies of potentials (I-VII) acquired from healthy dogs and interpeak latencies (I-III, I-V, III-V) were compared between left and right side. There were no significant differences between both sides except for the shorter latency of the VI potential in the left ear. Facial paralysis was diagnosed in four cases with severe chronic otitis externa-media. In conclusion, reference values of the laboratory for BAER in healthy dogs were obtained. Chronic otitis externa-media cause increasing latency rather than total deaf. BAER can be suggested as an ancillary diagnostic tool in ear disorders.