Using musical pitch interval comparisons to assess cochlear implant frequency-to-place maps

IntroductionMusic perception remains challenging for many cochlear implant (CI) recipients, due perhaps in part to a frequency mismatch that can occur between the original tonotopic cochlear map and the allocation of frequencies along the electrode array that occurs during programming. Individual di...

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Main Authors: Rebecca M. Lewis, Melanie L. Gilbert, Jordan A. Beim, Andrew J. Oxenham, Charles J. Limb
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-05-01
Series:Frontiers in Audiology and Otology
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Online Access:https://www.frontiersin.org/articles/10.3389/fauot.2025.1565883/full
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author Rebecca M. Lewis
Melanie L. Gilbert
Jordan A. Beim
Andrew J. Oxenham
Charles J. Limb
author_facet Rebecca M. Lewis
Melanie L. Gilbert
Jordan A. Beim
Andrew J. Oxenham
Charles J. Limb
author_sort Rebecca M. Lewis
collection DOAJ
description IntroductionMusic perception remains challenging for many cochlear implant (CI) recipients, due perhaps in part to a frequency mismatch that can occur between the original tonotopic cochlear map and the allocation of frequencies along the electrode array that occurs during programming. Individual differences in ear anatomy, electrode array length, and surgical insertion can lead to great variability in the positions of electrodes within the cochlea, but these differences are not typically accounted for by current CI programming techniques.ObjectivesFlat panel computed tomography (FPCT) can be used to visualize the location of the electrodes and calculate the corresponding spiral ganglion characteristic frequencies. Such FPCT-based CI frequency mapping may improve pitch perception accuracy, and thus music appreciation, as well as speech perception. The present study seeks to develop a behavioral assessment metric for how well place-based pitch is represented across the frequency spectrum by evaluating the accuracy with which listeners perceive and compare pitch intervals across different frequency regions.MethodsThe study included two groups: normal-hearing (NH) listeners and CI recipients. Listeners were asked to match the pitch interval created by two tones, played sequentially, across different frequency ranges to estimate the extent to which pitch is evenly distributed across the CI array. This test was initially evaluated with pure tones in normal-hearing listeners, using both unprocessed and vocoder-processed sounds to simulate both matched and mismatched frequency-to-place maps. We hypothesized that the vocoded stimuli would be more difficult to match in terms of pitch intervals than unprocessed stimuli, and that a warped map (as may occur with current clinical maps) would produce poorer matches than a veridical and well-aligned map (as may be achieved using FPCT-based frequency allocation).ResultsPreliminary results suggest that the task can reveal differences between veridical and warped maps in normal-hearing listeners under vocoded conditions. A small cohort of CI recipients were tested with the same pure tone stimuli (without vocoding). Performance of the CI recipients was similar to that of normal-hearing listeners, and both groups showed less accurate interval matching compared to NH listeners.DiscussionThe results suggest promise for this method when comparing the perceptual effects on pitch interval perception of traditional clinical maps and FPCT-based frequency allocation.
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spelling doaj-art-3f92b388035649f4a1751a92ecffd7272025-08-20T03:53:46ZengFrontiers Media S.A.Frontiers in Audiology and Otology2813-60552025-05-01310.3389/fauot.2025.15658831565883Using musical pitch interval comparisons to assess cochlear implant frequency-to-place mapsRebecca M. Lewis0Melanie L. Gilbert1Jordan A. Beim2Andrew J. Oxenham3Charles J. Limb4Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, United StatesDepartment of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, United StatesDepartment of Psychology, University of Minnesota, Minneapolis, MN, United StatesDepartment of Psychology, University of Minnesota, Minneapolis, MN, United StatesDepartment of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, United StatesIntroductionMusic perception remains challenging for many cochlear implant (CI) recipients, due perhaps in part to a frequency mismatch that can occur between the original tonotopic cochlear map and the allocation of frequencies along the electrode array that occurs during programming. Individual differences in ear anatomy, electrode array length, and surgical insertion can lead to great variability in the positions of electrodes within the cochlea, but these differences are not typically accounted for by current CI programming techniques.ObjectivesFlat panel computed tomography (FPCT) can be used to visualize the location of the electrodes and calculate the corresponding spiral ganglion characteristic frequencies. Such FPCT-based CI frequency mapping may improve pitch perception accuracy, and thus music appreciation, as well as speech perception. The present study seeks to develop a behavioral assessment metric for how well place-based pitch is represented across the frequency spectrum by evaluating the accuracy with which listeners perceive and compare pitch intervals across different frequency regions.MethodsThe study included two groups: normal-hearing (NH) listeners and CI recipients. Listeners were asked to match the pitch interval created by two tones, played sequentially, across different frequency ranges to estimate the extent to which pitch is evenly distributed across the CI array. This test was initially evaluated with pure tones in normal-hearing listeners, using both unprocessed and vocoder-processed sounds to simulate both matched and mismatched frequency-to-place maps. We hypothesized that the vocoded stimuli would be more difficult to match in terms of pitch intervals than unprocessed stimuli, and that a warped map (as may occur with current clinical maps) would produce poorer matches than a veridical and well-aligned map (as may be achieved using FPCT-based frequency allocation).ResultsPreliminary results suggest that the task can reveal differences between veridical and warped maps in normal-hearing listeners under vocoded conditions. A small cohort of CI recipients were tested with the same pure tone stimuli (without vocoding). Performance of the CI recipients was similar to that of normal-hearing listeners, and both groups showed less accurate interval matching compared to NH listeners.DiscussionThe results suggest promise for this method when comparing the perceptual effects on pitch interval perception of traditional clinical maps and FPCT-based frequency allocation.https://www.frontiersin.org/articles/10.3389/fauot.2025.1565883/fullvocoded stimuliflat panel computed tomography (FPCT)frequency-to-place mismatchmusical pitch intervalscochlear implant programmingpitch perception
spellingShingle Rebecca M. Lewis
Melanie L. Gilbert
Jordan A. Beim
Andrew J. Oxenham
Charles J. Limb
Using musical pitch interval comparisons to assess cochlear implant frequency-to-place maps
Frontiers in Audiology and Otology
vocoded stimuli
flat panel computed tomography (FPCT)
frequency-to-place mismatch
musical pitch intervals
cochlear implant programming
pitch perception
title Using musical pitch interval comparisons to assess cochlear implant frequency-to-place maps
title_full Using musical pitch interval comparisons to assess cochlear implant frequency-to-place maps
title_fullStr Using musical pitch interval comparisons to assess cochlear implant frequency-to-place maps
title_full_unstemmed Using musical pitch interval comparisons to assess cochlear implant frequency-to-place maps
title_short Using musical pitch interval comparisons to assess cochlear implant frequency-to-place maps
title_sort using musical pitch interval comparisons to assess cochlear implant frequency to place maps
topic vocoded stimuli
flat panel computed tomography (FPCT)
frequency-to-place mismatch
musical pitch intervals
cochlear implant programming
pitch perception
url https://www.frontiersin.org/articles/10.3389/fauot.2025.1565883/full
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