Electrodiagnostic Evaluation of Auditory Function

On the dual structure of the auditory brainstem response in dogs

“…All dogs showed ABR waveforms consistent with those previously reported in the literature (Kay et al, 1984;Sims and Moore, 1984;Bodenhamer et al, 1985;Marshall, 1985;Myers et al, 1985;Sims, 1988;Venker van Haagen et al, 1989;Shiu et al, 1997;Wilson and Mills, 2005). The ABR waveforms consisted of up to seven positive waves (peaks), with wave I occurring at a latency of approximately 1 to 2 ms depending on stimulus level, and successive waves occurring at approximately .5 ms to 1 ms intervals thereafter.…”

“…This electrode montage was chosen as it is the most commonly used montage in the dog [as summarised in Sims (1988) and Wilson and Mills (2005)]. The electrodes had been connected to the differential amplifier with a gain of 150,000 (artefact level ±16.3 lV), and the output of the amplifier had been connected to a personal computer running the Biologic Evoked Potential software.…”

“…The ABR in dogs is similar to the ABR in humans in that it consists of up to seven ''positive'' waves recorded within ten milliseconds of stimulus onset (note that these waves are not necessarily ''positive''; they simply identify periods when the vertex electrode is electrically positive with respect to the ear electrode). The ABR in dogs differs from the ABR in humans in that the first positive wave of the ABR in dogs begins at 1.0 to 1.5 ms (earlier than wave I in humans), each successive wave occurs within 1 ms of the previous wave (resulting in shorter interwave latencies than in humans), wave amplitudes (peak-totrough) range from less than 1 lV to approximately 6 lV (often resulting in larger wave amplitudes than in humans), and the early waves are larger than the later waves (the reverse of the pattern seen in humans) with wave II being substantially more prominent in dogs than in humans (Sims, 1988;Wilson and Mills, 2005). Fig.…”

“…The auditory brainstem response (ABR) is the best-recognised electrophysiological tool for the objective assessment of auditory function in dogs (Sims, 1988;Wilson and Mills, 2005). The ABR in dogs is similar to the ABR in humans in that it consists of up to seven ''positive'' waves recorded within ten milliseconds of stimulus onset (note that these waves are not necessarily ''positive''; they simply identify periods when the vertex electrode is electrically positive with respect to the ear electrode).…”

“…The ABR in dogs has been widely and successfully used both as a site-of-lesion tool and as an estimator of hearing thresholds (Sims, 1988;Wilson and Mills, 2005). Because of this success, the ABR in dogs has been intensively studied with dozens of literature reports describing its individual wave components, its suspected anatomical and physiological origins, its response to various pathologies, and its response to changes in subject, stimulus and recording factors (summarised in Sims, 1988 and. Despite this ample literature base, many aspects of the ABR in dogs remain poorly understood.…”