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23. Jahrestagung der Deutschen Gesellschaft für Audiologie

Deutsche Gesellschaft für Audiologie e. V.

03.09. - 04.09.2020, Cologne (online conference)

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On the frequency limit of ITD sensitivity in normal-hearing and hearing-impaired subjects

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  • presenting/speaker Mathias Dietz - Universität Oldenburg, Oldenburg, Deutschland
  • Helen Heinermann - Universität Oldenburg, Oldenburg, Deutschland
  • Jonas Klug - Universität Oldenburg, Oldenburg, Deutschland
  • Sven Herrmann - Universität Oldenburg, Oldenburg, Deutschland
  • Go Ashida - Universität Oldenburg, Oldenburg, Deutschland
  • Jörg Encke - Universität Oldenburg, Oldenburg, Deutschland

Deutsche Gesellschaft für Audiologie e.V.. 23. Jahrestagung der Deutschen Gesellschaft für Audiologie. Köln, 03.-04.09.2020. Düsseldorf: German Medical Science GMS Publishing House; 2020. Doc131

doi: 10.3205/20dga131, urn:nbn:de:0183-20dga1311

Published: September 3, 2020

© 2020 Dietz et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

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For young normal hearing listeners, previous studies have identified a pure-tone frequency limit very close to 1400 Hz, where an abrupt cliff-like increase in threshold interaural time difference (ITD) is observed [1]. Here, we investigate ITD sensitivity for a broader range of age and hearing status. Results from the best performing subjects underline the rigorous limit very close to 1,400 Hz. Data from older normal hearing and hearing impaired subjects, however, indicate a more gradual decline at lower frequencies, with no subject showing an abrupt limit. A physiologically inspired model of the auditory pathway is created to study the underlying mechanisms of ITD processing and to identify subject specific pathologies. Our modelling results indicate that the duration of the excitatory input to binaural neurons determines the steep upper frequency limit. The lower gradual roll-off in some individuals is accounted for in the model only by reducing the number of fibers projecting to the binaural interaction stage. Phase-locking, a prerequisite for ITD sensitivity, does not appear to be a limiting factor. Our ongoing modelling work is investigating the influence of hair-cell impairment and the role of inhibition in binaural interaction.

Outline

References

1.
Brughera A, Dunai L, Hartmann WM. Human interaural time difference thresholds for sine tones: the high-frequency limit. J Acoust Soc Am. 2013;133(5):2839-2855. DOI: 10.1121/1.4795778 External link