THRESHOLD CHANGES IN AUDITORY BRAIN-STEM RESPONSE (ABR) DUE TO THE ADMINISTRATION OF KANAMYCIN IN DOGS

Auditory brainstem response (ABR) is a useful method in evaluating aud itory function in human. To investigate the ABR threshold is more effe ctive than to pursue the trends in each component of ABR. In this stud y, tone burst sound stimuli were employed and the ABR threshold shift caused by kanamycin administration was investigated in dogs. In a seri es of monitoring of ABR against short-period auditory lesions, changes in the ABR waveform after intravenous administration of kanamycin wer e detected. These changes returned gradually and were reversible. The changes in ABR against long-period auditory function disorder were per ceived by an increase in the ABR threshold. The ABR threshold shift oc curred earlier in the high frequency sounds than in the lower frequenc y sounds. This is why amino glycoside antibiotics damage the cochlear hair cells in the basal layer and lead to the loss of hearing selectiv ely for high frequency tones. These findings suggest that tracing of t he ABR threshold by tone bursts could provide information that has a s pecificity for frequency in hearing tests and is a useful method in cl inical veterinary medicine or/and toxicological tests.