The effect of a coding strategy that removes temporally masked pulses on speech perception by cochlear implant users

Lamping, Wiebke; Goehring, Tobias; Marozeau, Jérémy; Carlyon, Robert P.

doi:10.1016/j.heares.2020.107969

Cited by 14 publications

(8 citation statements)

References 66 publications

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“…Finally, it will be important to determine whether the advances obtained by different approaches are additive -an issue that led one scientist to remark, only half-jokingly, that they had Carlyon & Goehring -21 st century CI 42 seen so many 5% improvements reported throughout their career that patients should now be scoring more that 100% on speech tests. For example, the various processing algorithms that enhance modulations across time (Koning and Wouters, 2016;Lamping et al, 2020) or across electrodes (Nogueira et al, 2016;Bolner et al, 2020;Lopez-Poveda et al, 2020) are likely addressing the same basic goal of increasing the contrast in the pattern of electrical stimulation (electrodogram), typically by attenuating or removing loweramplitude pulses. To the extent that different algorithms attenuate the same pulses their benefits may not sum.…”

Section: Improving Hearing With Existing CI Technology and Methodsmentioning

confidence: 99%

“…This "Temporal Integrator Processing Strategy (TIPS)" enhances the envelope modulations in each channel and may reduce unwanted charge interactions between pulses in nearby channels. Lamping et al (2020) reported that adding the TIPS processing stage to the CIS strategy produced an average of 2.4 dB improvement in the SNR for sentences masked by stationary noise in eight participants, and suggested that it could reduce power consumption substantially. Experimenters but not participants were aware of which condition was being tested.…”

Section: Experimental Strategiesmentioning

confidence: 99%

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Cochlear implant research and development in the 21st century: A critical update

Carlyon¹,

Goehring²

2021

Preprint

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Cochlear implants (CIs) are the world’s most successful sensory prosthesis and have been the subject of intense research and development in recent decades. We critically review the progress in CI research, and its success in improving patient outcomes, from the turn of the century to the present day. The introduction of directional microphones and of new noise-reduction and pre-processing algorithms have produced robust and sometimes substantial improvements. Improvements from novel speech-processing algorithms, the use of current-focussing methods, and individualised (patient-by-patient) de-activation of subsets of electrodes have been identified but have been more modest. We argue that incremental advances have and will continue to be made, that collectively these may substantially improve patient outcomes, but that the modest size of each individual advance will require greater attention to experimental design and power. We also briefly discuss the potential and limitations of revolutionary technologies, and suggest strategies for researchers to collectively maximise the potential of CIs to improve hearing in a wide range of listening situations.

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Section: Improving Hearing With Existing CI Technology and Methodsmentioning

confidence: 99%

Section: Experimental Strategiesmentioning

confidence: 99%

Cochlear implant research and development in the 21st century: A critical update

Carlyon¹,

Goehring²

2021

Preprint

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“…Finally, an adaptation of the Temporal Model was used by Lamping et al (2020) to devise a signal processing strategy (designated TIPS) that removed pulses that were more likely to be masked by preceding pulses. The authors used the sliding integration window of Eq.…”

Section: Multi-electrode Stimulimentioning

confidence: 99%

Applications of Phenomenological Loudness Models to Cochlear Implants

McKay

2021

Front. Psychol.

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Cochlear implants electrically stimulate surviving auditory neurons in the cochlea to provide severely or profoundly deaf people with access to hearing. Signal processing strategies derive frequency-specific information from the acoustic signal and code amplitude changes in frequency bands onto amplitude changes of current pulses emitted by the tonotopically arranged intracochlear electrodes. This article first describes how parameters of the electrical stimulation influence the loudness evoked and then summarizes two different phenomenological models developed by McKay and colleagues that have been used to explain psychophysical effects of stimulus parameters on loudness, detection, and modulation detection. The Temporal Model is applied to single-electrode stimuli and integrates cochlear neural excitation using a central temporal integration window analogous to that used in models of normal hearing. Perceptual decisions are made using decision criteria applied to the output of the integrator. By fitting the model parameters to a variety of psychophysical data, inferences can be made about how electrical stimulus parameters influence neural excitation in the cochlea. The Detailed Model is applied to multi-electrode stimuli, and includes effects of electrode interaction at a cochlear level and a transform between integrated excitation and specific loudness. The Practical Method of loudness estimation is a simplification of the Detailed Model and can be used to estimate the relative loudness of any multi-electrode pulsatile stimuli without the need to model excitation at the cochlear level. Clinical applications of these models to novel sound processing strategies are described.

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“…We believe that studying modulation processing at supra-threshold depths can not only shed light on the processing of modulation depths in a way that is more relevant to the perception of everyday sounds, but can also inform the development and evaluation of novel processing strategies. Data obtained with a number of such strategies suggest potential benefits from sharpening the modulation envelope (Green et al 2004 ; Laneau et al 2006 ; Monaghan and Seeber 2016 ; Vandali et al 2005 ; Vandali and van Hoesel 2011 ), replacing it entirely with single pulses at each envelope maximum (Smith et al 2014 ), or deleting pulses that would likely be masked by adjacent higher-amplitude pulses (Kludt et al 2021 ; Lamping et al 2020 ). These studies have improved, for example, the perception of modulation rate, the perception of speech in noise, and, in bilaterally implanted listeners, of interaural time differences (ITDs).…”

Section: Introductionmentioning

confidence: 99%

Modulation Depth Discrimination by Cochlear Implant Users

Monaghan

Carlyon

Deeks

2022

JARO

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Cochlear implants (CIs) convey the amplitude envelope of speech by modulating high-rate pulse trains. However, not all of the envelope may be necessary to perceive amplitude modulations (AMs); the effective envelope depth may be limited by forward and backward masking from the envelope peaks. Three experiments used modulated pulse trains to measure which portions of the envelope can be effectively processed by CI users as a function of AM frequency. Experiment 1 used a three-interval forced-choice task to test the ability of CI users to discriminate less-modulated pulse trains from a fully modulated standard, without controlling for loudness. The stimuli in experiment 2 were identical, but a two-interval task was used in which participants were required to choose the less-modulated interval, ignoring loudness. Catch trials, in which judgements based on level or modulation depth would give opposing answers, were included. Experiment 3 employed novel stimuli whose modulation envelope could be modified below a variable point in the dynamic range, without changing the loudness of the stimulus. Overall, results showed that substantial portions of the envelope are not accurately encoded by CI users. In experiment 1, where loudness cues were available, participants on average were insensitive to changes in the bottom 30% of their dynamic range. In experiment 2, where loudness was controlled, participants appeared insensitive to changes in the bottom 50% of the dynamic range. In experiment 3, participants were insensitive to changes in the bottom 80% of the dynamic range. We discuss potential reasons for this insensitivity and implications for CI speech-processing strategies.

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The effect of a coding strategy that removes temporally masked pulses on speech perception by cochlear implant users

Cited by 14 publications

References 66 publications

Cochlear implant research and development in the 21st century: A critical update

Cochlear implant research and development in the 21st century: A critical update

Applications of Phenomenological Loudness Models to Cochlear Implants

Modulation Depth Discrimination by Cochlear Implant Users

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