Evaluation of Fine Structure Coding in New Cochlear Implant Users with Tonotopic Fitting: a Prospective, Randomized, Double-Blind, Cross-Over Study
Abstract
Objectives.: Several studies have demonstrated the benefits of tonotopic fitting on speech-in-noise perception in new cochlear implant (CI) users. However, these studies used different coding strategies (CIS, HDCIS, FSP, FS4, or mixed) with different frequency spectra. The aim of this study was to assess the impact of fine structure (FS) cues on speech perception in noise and in quiet and music perception, in new CI users with a tonotopic fitting map. Methods.: A prospective, randomized, double-blind, 2-period crossover study was performed from April 2023 to June 2024. All participants had tonotopic fitting determined by using flat-panel computed tomography (CT) and reconstruction software based on the Greenwood function. 24 new CI users aged 18 years or older with either bilateral severe-to-profound sensorineural hearing loss or complete hearing loss for less than 5 years were recruited at a single tertiary referral center. Participants were randomized to FS followed by conventional coding, or the reverse sequence, for 6-week periods with speech and music assessments after each period. Results.: FS cues significantly improved speech recognition in noise for high signal-to-noise ratio (SNR = +9 dB, Mean Effect (ME) = 6.0%, Standardized effect size (SES) = 0.62, p = 0.010). A period effect was observed beyond + 6 dB of SNR (SNR = +9 dB, p = 0.010; SNR = +6 dB, p = 0.018) without a statistically significant group effect. Speech recognition and tonal audiometry in quiet were not affected by FS coding. Melodic contour identification was enhanced by FS cues (ME = 7.2%, SES = 0.51, p = 0.030), and, in an exploratory subset analysis, low-frequency pitch discrimination was also improved (ME = 8.5 Hz, SES = 0.72, p = 0.04). Over 75% of the participants retained the tonotopic map with FS coding after study completion. Conclusion.: FS coding strategies on tonotopic maps may improve speech recognition in noise at favorable SNRs, without compromising speech understanding in quiet. It may also enhance selected complex sound perception aspects, particularly pitch- and contour-related processing, while benefits for subjective music perception appear less consistent.
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BibTeX
@article{creff2026evaluation,
title = {{Evaluation of Fine Structure Coding in New Cochlear Implant Users with Tonotopic Fitting: a Prospective, Randomized, Double-Blind, Cross-Over Study}},
author = {Gwenaelle Creff and Nicolas Bernard-Leliboux and Hermine Bourdon and Vincent Péan and Nicolas Wallaert and Raphaël Tisserand and Benoît Godey},
journal = {Clinical and Experimental Otorhinolaryngology},
year = {2026},
month = oct,
doi = {10.21053/ceo.2026-00039},
url = {https://hal.science/hal-05785836v1},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Evaluation of Fine Structure Coding in New Cochlear Implant Users with Tonotopic Fitting: a Prospective, Randomized, Double-Blind, Cross-Over Study
AU - Gwenaelle Creff
AU - Nicolas Bernard-Leliboux
AU - Hermine Bourdon
AU - Vincent Péan
AU - Nicolas Wallaert
AU - Raphaël Tisserand
AU - Benoît Godey
PY - 2026
DA - 2026/10/08
JO - Clinical and Experimental Otorhinolaryngology
DO - 10.21053/ceo.2026-00039
UR - https://hal.science/hal-05785836v1
AB - Objectives.: Several studies have demonstrated the benefits of tonotopic fitting on speech-in-noise perception in new cochlear implant (CI) users. However, these studies used different coding strategies (CIS, HDCIS, FSP, FS4, or mixed) with different frequency spectra. The aim of this study was to assess the impact of fine structure (FS) cues on speech perception in noise and in quiet and music perception, in new CI users with a tonotopic fitting map. Methods.: A prospective, randomized, double-blind, 2-period crossover study was performed from April 2023 to June 2024. All participants had tonotopic fitting determined by using flat-panel computed tomography (CT) and reconstruction software based on the Greenwood function. 24 new CI users aged 18 years or older with either bilateral severe-to-profound sensorineural hearing loss or complete hearing loss for less than 5 years were recruited at a single tertiary referral center. Participants were randomized to FS followed by conventional coding, or the reverse sequence, for 6-week periods with speech and music assessments after each period. Results.: FS cues significantly improved speech recognition in noise for high signal-to-noise ratio (SNR = +9 dB, Mean Effect (ME) = 6.0%, Standardized effect size (SES) = 0.62, p = 0.010). A period effect was observed beyond + 6 dB of SNR (SNR = +9 dB, p = 0.010; SNR = +6 dB, p = 0.018) without a statistically significant group effect. Speech recognition and tonal audiometry in quiet were not affected by FS coding. Melodic contour identification was enhanced by FS cues (ME = 7.2%, SES = 0.51, p = 0.030), and, in an exploratory subset analysis, low-frequency pitch discrimination was also improved (ME = 8.5 Hz, SES = 0.72, p = 0.04). Over 75% of the participants retained the tonotopic map with FS coding after study completion. Conclusion.: FS coding strategies on tonotopic maps may improve speech recognition in noise at favorable SNRs, without compromising speech understanding in quiet. It may also enhance selected complex sound perception aspects, particularly pitch- and contour-related processing, while benefits for subjective music perception appear less consistent.
SN - 1976-8710
SN - 2005-0720
ER -