R Gonçalves1, J Freeman, J Penderis. 1. Institute of Comparative Medicine, Division of Companion Animal Sciences, Faculty of Veterinary Medicine, University of Glasgow, Glasgow, UK.
Abstract
BACKGROUND: The brainstem auditory-evoked response (BAER) is currently the standard evaluation method of hearing in dogs. In asymmetrical hearing loss in human patients, simultaneous presentation of masking noise to the nontest ear is routinely performed during BAER to eliminate the crossover effect. HYPOTHESIS: The crossover effect occurs during canine BAER, and masking noise of 20 decibels (dB) below click stimulus intensity is sufficient to abolish this effect. ANIMALS: Fifty-six Dalmatian puppies with confirmed unilateral deafness. METHODS: The BAER was elicited with 80 and 100 dB normalized hearing level (dBnHL) stimulus intensity in the deaf ear. The 100 dBnHL stimulus was repeated while simultaneously applying 80 dBnHL white masking noise to the nontest ear. RESULTS: Ten dogs were excluded because of BAER trace baseline fluctuation. In the remaining 46 dogs, 8 dogs had no waveforms, but 38 dogs had an identifiable wave-V in the deaf ear BAER at 80 dBnHL intensity stimulus. At 100 dBnHL intensity stimulus, all but 1 dog had a discernible wave-V in the deaf ear BAER. The deaf ear BAER waveforms were abolished by white masking noise at 80 dBnHL in the nontest ear in all dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Abolition of BAER wave-V in the deaf ear by white masking noise in the nontest ear suggests that this wave is caused by the crossover effect. beta distribution indicates 95% confidence that white masking noise, at 20 dB below click stimulus intensity, would abolish this crossover effect in over 90% of the dogs. This supports using masking noise in the nontest ear during canine BAER.
BACKGROUND: The brainstem auditory-evoked response (BAER) is currently the standard evaluation method of hearing in dogs. In asymmetrical hearing loss in humanpatients, simultaneous presentation of masking noise to the nontest ear is routinely performed during BAER to eliminate the crossover effect. HYPOTHESIS: The crossover effect occurs during canine BAER, and masking noise of 20 decibels (dB) below click stimulus intensity is sufficient to abolish this effect. ANIMALS: Fifty-six Dalmatian puppies with confirmed unilateral deafness. METHODS: The BAER was elicited with 80 and 100 dB normalized hearing level (dBnHL) stimulus intensity in the deaf ear. The 100 dBnHL stimulus was repeated while simultaneously applying 80 dBnHL white masking noise to the nontest ear. RESULTS: Ten dogs were excluded because of BAER trace baseline fluctuation. In the remaining 46 dogs, 8 dogs had no waveforms, but 38 dogs had an identifiable wave-V in the deaf ear BAER at 80 dBnHL intensity stimulus. At 100 dBnHL intensity stimulus, all but 1 dog had a discernible wave-V in the deaf ear BAER. The deaf ear BAER waveforms were abolished by white masking noise at 80 dBnHL in the nontest ear in all dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Abolition of BAER wave-V in the deaf ear by white masking noise in the nontest ear suggests that this wave is caused by the crossover effect. beta distribution indicates 95% confidence that white masking noise, at 20 dB below click stimulus intensity, would abolish this crossover effect in over 90% of the dogs. This supports using masking noise in the nontest ear during canine BAER.
Authors: Raluca Ștefănescu; Constantin Roman; Liviu Dan Miron; Gheorghe Solcan; Vasile Vulpe; Luminița Diana Hrițcu; Mihai Musteata Journal: Animals (Basel) Date: 2020-02-02 Impact factor: 2.752