Cochlear implants (CIs) take advantage of the tonotopic structure of the cochlea, stimulating areas progressively closer to the base as the input sound frequency increases. One key fitting parameter in a CI is the frequency table wherein input acoustic frequencies are allocated to intracochlear electrodes. Under current clinical practice, all users of a given CI model receive basically the same frequency table. In postlingually hearing impaired CI users, this one-size-fits-all approach may introduce mismatches between input acoustic frequency and the characteristic frequency of the neurons that are stimulated. Although human listeners can adapt to these distortions, there is growing evidence that sometimes this adaptation process may be incomplete. Both the adaptation process and its possible incompleteness have important consequences to speech perception in the postlingually hearing impaired CI population.
The first aim of the proposed work is to measure the extent and the time course of this adaptation process, which will be explored in two experiments. Experiment 1 will study recently implanted CI users and follow them for a year, using four different methods to measure adaptation to frequency mismatch, complemented by a battery of speech perception, psychophysical, cognitive, and anatomical measurements. Experiment two will examine the same questions but with a group of CI users with long term experience (at least one year). Both experiments will also have a second aim: using the anatomical and cognitive measures to predict which individuals are more likely to suffer incomplete adaptation to their clinical frequency tables. Lastly, Experiment 3 will address the third aim of the proposed research: to test the hypothesis that frequency tables intended to reduce frequency mismatch will improve speech perception scores in those CI users who show incomplete adaptation. Part of the proposed work involves developing and refining software and hardware tools to facilitate the search for alternative frequency tables that may help minimize frequency mismatch. In summary, the experiments described in this proposal will provide new insights about the nature of auditory adaptation to a modified peripheral frequency map by postlingually hearing impaired CI users, and will also provide guidance to the clinicians who are in charge of fitting these devices. Studies like the present ones will help translate basic knowledge into clinical practice, and will make clinical practice more data- and theory-driven.

Public Health Relevance

The proposed research aims to understand how human listeners adapt to distortions in their auditory frequency maps. This knowledge may help improve speech perception in cochlear implant users who have difficulty adapting to the standard frequency tables programmed into their speech processors. The project also aims to develop the hardware and software tools that will allow the translation of these scientific findings into actual clinical practice.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
2R01DC003937-12A1
Application #
8010075
Study Section
Special Emphasis Panel (ZRG1-IFCN-M (02))
Program Officer
Donahue, Amy
Project Start
1999-01-15
Project End
2015-08-31
Budget Start
2010-09-01
Budget End
2011-08-31
Support Year
12
Fiscal Year
2010
Total Cost
$360,188
Indirect Cost
Name
New York University
Department
Otolaryngology
Type
Schools of Medicine
DUNS #
121911077
City
New York
State
NY
Country
United States
Zip Code
10016
Sagi, Elad; Svirsky, Mario A (2018) Deactivating cochlear implant electrodes to improve speech perception: A computational approach. Hear Res 370:316-328
Azadpour, Mahan; McKay, Colette M; Svirsky, Mario A (2018) Effect of Pulse Rate on Loudness Discrimination in Cochlear Implant Users. J Assoc Res Otolaryngol 19:287-299
Tan, Chin-Tuan; Martin, Brett A; Svirsky, Mario A (2018) A potential neurophysiological correlate of electric-acoustic pitch matching in adult cochlear implant users: Pilot data. Cochlear Implants Int 19:198-209
Glennon, Erin; Carcea, Ioana; Martins, Ana Raquel O et al. (2018) Locus coeruleus activation accelerates perceptual learning. Brain Res :
Cohen, Samuel M; Svirsky, Mario A (2018) Duration of unilateral auditory deprivation is associated with reduced speech perception after cochlear implantation: A single-sided deafness study. Cochlear Implants Int :1-6
Tan, Chin-Tuan; Martin, Brett; Svirsky, Mario A (2017) Pitch Matching between Electrical Stimulation of a Cochlear Implant and Acoustic Stimuli Presented to a Contralateral Ear with Residual Hearing. J Am Acad Audiol 28:187-199
Fitzgerald, Matthew B; Prosolovich, Ksenia; Tan, Chin-Tuan et al. (2017) Self-Selection of Frequency Tables with Bilateral Mismatches in an Acoustic Simulation of a Cochlear Implant. J Am Acad Audiol 28:385-394
Jethanamest, Daniel; Azadpour, Mahan; Zeman, Annette M et al. (2017) A Smartphone Application for Customized Frequency Table Selection in Cochlear Implants. Otol Neurotol 38:e253-e261
Sagi, Elad; Svirsky, Mario A (2017) Contribution of formant frequency information to vowel perception in steady-state noise by cochlear implant users. J Acoust Soc Am 141:1027
King, Julia; Shehu, Ina; Roland Jr, J Thomas et al. (2016) A physiological and behavioral system for hearing restoration with cochlear implants. J Neurophysiol 116:844-58

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