Bilateral Congenital Deafness in a White Bull Terrier; Brainstem Auditory Evoked Response Findings

A 2-month-old, intact female white Bull Terrier presented because of suspected deafness. The coat color was predominantly white and the iris color, of both eyes, was brown. The dog did not respond to the owner's voice when the sound stimuli were presented outside of the visual field; however, the dog responded to visual gestures. The other physical, neurological, otoscopic, radiographic, and blood examinations were unremarkable. To assess the apparent deafness, brainstem auditory evoked responses (BAER) were recorded and analyzed in the dog with suspected deafness as well as a normal littermate. The response in the normal littermate consisted of a series of five wave peaks (I-V) with decreased amplitude and prolonged latency as the stimulus intensity decreased. The BAER from the dog suspected of deafness appeared as a flat line and did not reveal identifiable peaks that corresponded to those found in the normal littermate. Thus, congenital, sensorineural and bilateral deafness was confirmed by the BAER.