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.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Special Emphasis Panel (ZRG1-IFCN-M (02))
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Donahue, Amy
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New York University
Schools of Medicine
New York
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Svirsky, Mario A; Talavage, Thomas M; Sinha, Shivank et al. (2015) Gradual adaptation to auditory frequency mismatch. Hear Res 322:163-70
Svirsky, Mario (2014) Cochlear implants: studies at the research triangle institute. Ear Hear 35:137
Watanabe, H; Velmurugan, J; Mirkin, M V et al. (2014) Scanning electrochemical microscopy as a novel proximity sensor for atraumatic cochlear implant insertion. IEEE Trans Biomed Eng 61:1822-32
Fitzgerald, Matthew B; Sagi, Elad; Morbiwala, Tasnim A et al. (2013) Feasibility of real-time selection of frequency tables in an acoustic simulation of a cochlear implant. Ear Hear 34:763-72
Tan, Chin-Tuan; Svirsky, Mario; Anwar, Abbas et al. (2013) Real-time measurement of electrode impedance during intracochlear electrode insertion. Laryngoscope 123:1028-32
Smalt, Christopher J; Gonzalez-Castillo, Javier; Talavage, Thomas M et al. (2013) Neural correlates of adaptation in freely-moving normal hearing subjects under cochlear implant acoustic simulations. Neuroimage 82:500-9
Svirsky, Mario A; Sagi, Elad; Meyer, Ted A et al. (2011) A mathematical model of medial consonant identification by cochlear implant users. J Acoust Soc Am 129:2191-200
Jethanamest, Daniel; Tan, Chin-Tuan; Fitzgerald, Matthew B et al. (2010) A new software tool to optimize frequency table selection for cochlear implants. Otol Neurotol 31:1242-7
Loebach, Jeremy L; Pisoni, David B; Svirsky, Mario A (2010) Effects of semantic context and feedback on perceptual learning of speech processed through an acoustic simulation of a cochlear implant. J Exp Psychol Hum Percept Perform 36:224-34
Sagi, Elad; Fu, Qian-Jie; Galvin 3rd, John J et al. (2010) A model of incomplete adaptation to a severely shifted frequency-to-electrode mapping by cochlear implant users. J Assoc Res Otolaryngol 11:69-78

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