1UBC - University of British Columbia (Vancouver Campus, , 2329 West Mall, Vancouver, BC, V6T 1Z4 /
Okanagan Campus, 3333 University Way, Kelowna, BC, V1V 1V7 - Canada)
Abstract : Correlations between inner ear morphology and auditory sensitivity in the same individual are extremely difficult to obtain for stranded cetaceans. Animals in captivity and rehabilitation offer the opportunity to combine several techniques to study the auditory system and cases of hearing impairment in a controlled environment. Morphologic and auditory findings from two beluga whales (Delphinapterus leucas) in managed care are presented. Cochlear analysis of a 21-year-old beluga whale showed bilateral high-frequency hearing loss. Specifically, scanning electron microscopy of the left ear revealed sensory cell death in the first 4.9 mm of the base of the cochlea with scar formation. Immunofluorescence microscopy of the right ear confirmed the absence of hair cells and type I afferent innervation in the first 6.6 mm of the base of the cochlea, most likely due to an ischemia. Auditory evoked potentials (AEPs) measured 1.5 years prior this beluga's death showed a generalized hearing loss, being more pronounced in the high frequencies. This individual might have had a mixed hearing loss that would explain the generalized hearing impairment. Conversely, based on AEP evaluation, her mother had normal hearing and subsequent cochlear analysis did not feature any apparent sensorineural pathology. This is believed to be the first study to compare two cochlear analysis techniques and hearing sensitivity measurements from AEPs in cetaceans. The ability to combine morphological and auditory data is crucial to validate predictions of cochlear frequency maps based on morphological features. In addition, our study shows that these three complementary analysis techniques lead to comparable results, thus improving our understanding of how hearing impairment can be detected in stranding cases.
https://hal.umontpellier.fr/hal-03176584 Contributeur : Anthony HerradaConnectez-vous pour contacter le contributeur Soumis le : lundi 22 mars 2021 - 15:06:23 Dernière modification le : jeudi 19 mai 2022 - 14:56:03 Archivage à long terme le : : mercredi 23 juin 2021 - 18:52:00
Maria Morell, Stephen Raverty, Jason Mulsow, Martin Haulena, Lance Barrett-Lennard, et al.. Combining Cochlear Analysis and Auditory Evoked Potentials in a Beluga Whale With High-Frequency Hearing Loss. Frontiers in Veterinary Science, Frontiers Media, 2020, 7, pp.534917. ⟨10.3389/fvets.2020.534917⟩. ⟨hal-03176584⟩