2008 Volume 61 Issue 2 Pages 145-149
Unilateral otitis media-interna was diagnosed in a dog (Welsh corgy, female, three-year-old) with severe atrophy of the masticatory muscles by computed tomography (CT) and brainstem auditory evoked potentials (BAEP) test. Because the dog did not have a history of otitis externa, difficulty in swallowing caused by atrophy of masticatory muscles had the potential to lead to otitis media-interna. Auditory activity was estimated using BAEP test. The threshold obtained by the stimulation of the affected ear was elevated 20 dB above that of the unaffected ear The neak latencies of each wave increased by stimulation of the affected ear in comparison to those of unaffected ear. Interpeak latencies (IPLs) between wave I and V and between wave I and III decreased with affected ear stimulation, but the M-VIPL showed the same value at 90dBHL stimulation. The slopes of the intensity-latency (I-L) curve of wave V with affected ear stimulation produced a larger value than those obtained from unaffected ear stimulation. Similar BAEP findings have been reported in a human patient with a cochlear hearing loss. Although vestibular signs such as head tilt or spontaneous nystagmus were not observed, not only conductive deafness but also sensorineural deafness with impairment of cochlear function could occur in this case.
