Information theoretic evaluation of a noiseband-based cochlear implant simulator

Aguiar, Daniel E.; Taylor, Natalie; Li, Jing; Gazanfari, Daniel K.; Talavage, Thomas M.; Laflen, J. M.; Neuberger, Heidi; Svirsky, Mario A.

doi:10.1016/j.heares.2015.09.008

Cited by 5 publications

(4 citation statements)

References 33 publications

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“…Listening in noise is a clear challenge, which is not handled in the same way by CI users and NH people. Noise flattens the spectrum and the subsequent structures in the auditory system do not react identically [37]. The study of speech recognition in noise has become of great interest as it is present in daily listening conditions.…”

Section: Listening In Noisementioning

confidence: 99%

Hearing in Noise: The Importance of Coding Strategies—Normal-Hearing Subjects and Cochlear Implant Users

et al. 2019

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Two schemes are mainly used for coding sounds in cochlear implants: Fixed-Channel and Channel-Picking. This study aims to determine the speech audiometry scores in noise of people using either type of sound coding scheme. Twenty normal-hearing and 45 cochlear implant subjects participated in this experiment. Both populations were tested by using dissyllabic words mixed with cocktail-party noise. A cochlear implant simulator was used to test the normal-hearing subjects. This simulator separated the sound into 20 spectral channels and the eight most energetic were selected to simulate the Channel-Picking strategy. For normal-hearing subjects, we noticed higher scores with the Fixed-Channel strategy than with the Channel-Picking strategy in the mid-range signal-to-noise ratios (0 to +6 dB). For cochlear implant users, no differences were found between the two coding schemes but we could see a slight advantage for the Fixed-Channel strategies over the Channel-Picking strategies. For both populations, a difference was observed for the signal-to-noise ratios at 50% of the maximum recognition plateau in favour of the Fixed-Channel strategy. To conclude, in the most common signal-to-noise ratio conditions, a Fixed-Channel coding strategy may lead to better recognition percentages than a Channel-Picking strategy. Further studies are indicated to confirm this.

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Section: Listening In Noisementioning

confidence: 99%

Hearing in Noise: The Importance of Coding Strategies—Normal-Hearing Subjects and Cochlear Implant Users

et al. 2019

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“…Cochlear implants (CI) have successfully restored partial hearing to over 400,000 deaf persons in the world and the rhythm of implantations is high in the world with a minimal rate of about 30,000 implantations [1].…”

Section: Cochlear Implants and Agingmentioning

confidence: 99%

“…Then other settings on the strategy have their influence: sampling rate, filters settings, length of the time frame (window), and they have been studied by many authors [1,18,19,20]. Most of the studies concluded to an advantage of the CIS coding over n-of-m. Then, the Advanced Combination Encoder (ACE) scheme is very efficient; it uses a very fast updating of the data and therefore provides a fine temporal analysis of the signal, indicating that spectrum is not the only component of speech.…”

Section: Strategymentioning

confidence: 99%

Cochlear Implants: Consequences of Microphone Aging on Speech Recognition

Berger‐Vachon

Cucis

Truy

et al. 2017

Complex Systems: Solutions and Challenges in Economics, Management and Engineering

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Aging is a general phenomenon which affects everything and everybody in this world. Designed for the rehabilitation of profound deafness, cochlear implants (CI) do not escape to this general rule. One very insidious effect concerns the microphone as an ongoing drift occurs over the time. In this work we wish to assess the consequences of this evolution on speech recognition. In order to perform this task, a general population of CI users and NH subjects (using a CI simulator) participated to this study. They listened to French dissyllabic words and we recorded recognition percentages. Words were presented to the listeners in noise with a variable signal to noise ratio (SNR) and the percentages ranged from 0% to 100%. For the CI simulator, the drift was simulated from data coming from figures measured on regular hearing aids. This choice seems relevant as CIs and hearing aids use the same microphones. Also, the CI simulator we used, picked up the general principles of a vocoder to represent the classical coding strategies used in CIs ("CIS-like" and n-of-m). With CI users, the results were compared before and after cleaning the microphones; also, in a subgroup of CI users, we performed the replacement of the head filter protecting the microphone and the recognition percentages were compared with those coming from the standard "Brush and Blow" cleaning procedure. The results have been revisited and quantified after a curve fitting. The outcomes indicated that the "CIS-like" coding schemes were less sensitive to aging than the n-of-m strategies. Also, cleaning ameliorated the recognition performances, but the increase was not dramatically high. Furthermore, the improvement mainly occurred in the middle of the SNR range where the noise was not too intense. We made these observations with CI users and with NH subjects indicated that the results should be linked to the properties of the signal. Finally, as we cannot stop the consequences of aging, we can set up an action plan to reduce its effect. And this is true in everyday life. In the case of CIs, a lot of solutions are available, among them the choice of the sound coding strategy and the periodicity of the clinical check and device setting.

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“…Simulations with less than eight channels presented to normal-hearing listeners provide speech intelligibility scores in the same range as CI patients [ 1 ], [ 2 ]. Despite this good result, some researchers argue that the vocoded information does not offer the same sound quality as that of CIs and suggest the existence of perceptual and informational discrepancies between CI stimulation and performance-matched acoustical simulations [ 3 – 6 ]. Thus, a similar level of performance obtained for both real and simulated CI may hide different patterns of errors, limiting the validity of acoustic simulations through vocoders to evaluate new coding strategies.…”

Section: Introductionmentioning

confidence: 99%

The sound sensation of a pure tone in cochlear implant recipients with single-sided deafness

Marozeau

Gnansia²,

Ardoint³

et al. 2020

PLoS ONE

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Ten cochlear implant (CI) users with single-sided deafness were asked to vary the parameters of an acoustic sound played to their contralateral ear to characterize the perception evoked by a pure tone played through the direct audio input of their CI. Two frequencies, centered on an apical and a medial electrode, were tested. In six subjects, the electrode positions were estimated on CT scans. The study was divided in 3 experiments in which the parameters of the acoustic sound varied. The listeners had to vary the frequency of a pure tone (Exp.1), the center frequency and the bandwidth of a filter applied to a harmonic complex sound (Exp.2), and the frequency of the components and the inharmonicity factor of a complex sound (Exp.3). Two testing sessions were performed at 3 and 12 months after activation. The mean results of Exp. 1 showed that the frequency of the matched tone was significantly lower for the apical than for the medial stimulus. In Exp.2, the mean center frequencies of the filters were also significantly lower for the apical than for the medial stimulus. As this parameter modifies the energy ratio between the high and low-frequency components, this result suggests that the medial stimulus was perceived with a brighter timbre than the apical stimulus. In Exp.3, the mean frequencies of the components were not significantly different between the sounds resulting from the stimulation of the two electrodes, but were significantly lower at the12-month session compared to the 3-month visit. These results suggest that a change in place of excitation may be perceived as a change in timbre rather than a change in pitch, and that an effect of adaptation can be observed.

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Information theoretic evaluation of a noiseband-based cochlear implant simulator

Cited by 5 publications

References 33 publications

Hearing in Noise: The Importance of Coding Strategies—Normal-Hearing Subjects and Cochlear Implant Users

Hearing in Noise: The Importance of Coding Strategies—Normal-Hearing Subjects and Cochlear Implant Users

Cochlear Implants: Consequences of Microphone Aging on Speech Recognition

The sound sensation of a pure tone in cochlear implant recipients with single-sided deafness

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