Investigating Auditory Brainstem Response Correlates of Basilar Membrane Nonlinearities in Dolphins
Abstract
Assessment of outer hair cell function within the mammalian auditory system is important for identifying hearing loss and understanding the underlying mechanisms. This report describes a series of experiments to test the feasibility of using noninvasive auditory brainstem response measurements to assess basilar membrane nonlinearities (and thus outer hair cell function) in the bottlenose dolphin. Auditory brainstem responses were measured to probe sound stimuli with and without additional masking noise. Both simultaneous masking and forward masking paradigms were used. Probe and/or masker level were varied across trials. Across various experiments, the delay between the masker and probe, the probe frequency, masker frequency, and masker waveforms were varied. The results showed no evidence of compressive nonlinearities in any of the measurements. The most likely reasons involve the relatively high ambient noise in the test environment and the relatively high signal levels. Future testing should be conducted in a quiet underwater environment, such as a pool, with young animals with normal hearing. To assess whether ABR magnitude-level functions can be reliably used to directly assess outer hair cell function, magnitude-level functions should be assessed at multiple frequencies from a larger sample of dolphins with normal hearing and hearing loss.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2023
- Accession Number
- AD1205820
Entities
People
- Dorian S. Houser
- James J Finneran
- Jason Mulsow
- Madelyn G Strahan
- Robert F. Burkard
Organizations
- National Marine Mammal Foundation
- Naval Information Warfare Center Pacific
- State University of New York