Assessment and improvement of sound quality in cochlear implant users

Caldwell, Meredith; Jiam, Nicole T.; Limb, Charles J.

doi:10.1002/lio2.71

Cited by 45 publications

(37 citation statements)

References 78 publications

(140 reference statements)

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“…A bias toward unvoiced stops was found, a phenomenon that only occurred for the CI group and hence probably is implant related. This may be related to two main issues: (1) implants convey the F0 in voiced sounds rather poorly due to missing temporal information in the electrical signal for most implant models and to the electrode’s insertion depth possibly being too shallow to cover the whole cochlea (Hamzavi and Arnoldner, 2006; Svirsky et al, 2015; Caldwell et al, 2017) and (2) the VOT makes the unvoiced stops much easier to perceive than the voiced stops due to the aspirated pause between the stop and the following vowel in the VCV syllables.…”

Section: Discussionmentioning

confidence: 99%

Consonant and Vowel Confusions in Well-Performing Children and Adolescents With Cochlear Implants, Measured by a Nonsense Syllable Repetition Test

et al. 2019

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Although the majority of early implanted, profoundly deaf children with cochlear implants (CIs), will develop correct pronunciation if they receive adequate oral language stimulation, many of them have difficulties with perceiving minute details of speech. The main aim of this study is to measure the confusion of consonants and vowels in well-performing children and adolescents with CIs. The study also aims to investigate how age at onset of severe to profound deafness influences perception. The participants are 36 children and adolescents with CIs (18 girls), with a mean ( SD ) age of 11.6 (3.0) years (range: 5.9–16.0 years). Twenty-nine of them are prelingually deaf and seven are postlingually deaf. Two reference groups of normal-hearing (NH) 6- and 13-year-olds are included. Consonant and vowel perception is measured by repetition of 16 bisyllabic vowel-consonant-vowel nonsense words and nine monosyllabic consonant-vowel-consonant nonsense words in an open-set design. For the participants with CIs, consonants were mostly confused with consonants with the same voicing and manner, and the mean ( SD ) voiced consonant repetition score, 63.9 (10.6)%, was considerably lower than the mean ( SD ) unvoiced consonant score, 76.9 (9.3)%. There was a devoicing bias for the stops; unvoiced stops were confused with other unvoiced stops and not with voiced stops, and voiced stops were confused with both unvoiced stops and other voiced stops. The mean ( SD ) vowel repetition score was 85.2 (10.6)% and there was a bias in the confusions of [i:] and [y:]; [y:] was perceived as [i:] twice as often as [y:] was repeated correctly. Subgroup analyses showed no statistically significant differences between the consonant scores for pre- and postlingually deaf participants. For the NH participants, the consonant repetition scores were substantially higher and the difference between voiced and unvoiced consonant repetition scores considerably lower than for the participants with CIs. The participants with CIs obtained scores close to ceiling on vowels and real-word monosyllables, but their perception was substantially lower for voiced consonants. This may partly be related to limitations in the CI technology for the transmission of low-frequency sounds, such as insertion depth of the electrode and ability to convey temporal information.

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Section: Discussionmentioning

confidence: 99%

Consonant and Vowel Confusions in Well-Performing Children and Adolescents With Cochlear Implants, Measured by a Nonsense Syllable Repetition Test

et al. 2019

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“…These findings suggest that perception of segmental rhythm in speech evolves from sensitivity to syllabic complexity to variation in consonant intervals and the amount of vocalic space with age. Children who are deprived of normal rhythmic development, such as prelingually deafened CI users, are notably deficient in the detection of voice emotion compared with their normal hearing counterparts . This observation highlights the unique albeit limited contribution of CIs (as opposed to vibrotactile stimulation) in providing gross temporal structure (e.g., sensitivity to the amplitude envelope) and sound quality appraisal (e.g., timbre and dynamic range) to its listeners.…”

Section: Rhythm Perception In Speechmentioning

confidence: 99%

Rhythm processing in cochlear implant−mediated music perception

Jiam

Limb

2019

Annals of the New York Academy of Sciences

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Cochlear implants (CIs) are biomedical devices that provide sound to people with severe‐to‐profound hearing loss by direct electrical stimulation of auditory neurons in the cochlea. Despite the remarkable achievements with respect to speech perception in quiet environments, music perception with CIs remains generally poor due to the degradation of auditory input. Prior studies have shown that both pitch perception and timbre discrimination are poor in CI users, whereas the performance on rhythmic tasks is nearly equivalent to normal hearing participants. There are several caveats, however, to this generalization regarding rhythm processing for CI users. The purpose of this article is to summarize the literature on rhythmic perception for CI users while highlighting important limitations within these studies. We will also identify areas for future research and development of CI‐mediated music processing. It is likely that rhythm processing will continue to advance as our understanding of electrical current delivery to the auditory nerve improves.

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“…Several studies show that PE stimulation implemented in a sound coding strategy to transmit low frequency information has a significant effect on sound quality (e.g. Munjal et al, 2015; Nogueira et al, 2015; Caldwell et al, 2017). Munjal et al (2015) found out that the use of PE stimulation when listening to music has a positive effect in the ability to detect alterations in low frequency or bass content in music.…”

Section: Discussionmentioning

confidence: 99%

Perceptual changes with monopolar and phantom electrode stimulation

et al. 2018

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Phantom electrode (PE) stimulation is achieved by simultaneously stimulating out-of-phase from two adjacent intra-cochlear electrodes with different amplitudes. If the basal electrode stimulates with a smaller amplitude than the apical electrode of the pair, the resulting electrical field is pushed away from the basal electrode producing a lower pitch. There is great interest in using PE stimulation in a processing strategy as it can be used to provide stimulation to regions of the cochlea located more apically than the most apical contact on the electrode array. The result is that even lower pitch sensations can be provided without additional risk of a deeper insertion. However, it is unknown if there are perceptual differences between monopolar (MP) and PE stimulation other than a shift in place pitch. Furthermore, it is unknown if the effect and magnitude of changing from MP to PE stimulation is dependent on electrode location. This study investigates the perceptual differences (including pitch and other sound quality differences) at multiple electrode positions using MP and PE stimulation using both a multidimensional scaling procedure (MDS) and a traditional scaling procedure. 10 Advanced Bionics users reported the perceptual distances between 5 single electrode (typically 1, 3, 5, 7, and 9) stimuli in either MP or PE (σ = 0.5) mode. Subjects were asked to report how perceptually different each pair of stimuli were using any perceived differences except loudness. Subsequently, each stimulus was presented in isolation and subjects scaled how "high" or how "clean" each sounded. Results from the MDS task suggest that perceptual differences between MP and PE stimulation can be explained by a single dimension. The traditional scaling suggests that the single dimension is place pitch. PE stimulation elicits lower pitch perceptions in all cochlear regions. Analysis of Cone Beam Computer Tomography (CBCT) data suggests that PE stimulation may be more effective at the apical part of the cochlea. PE stimulation can be used for new sound coding strategies in order to extend the pitch range for cochlear implant (CI) users without perceptual side effects.

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Assessment and improvement of sound quality in cochlear implant users

Cited by 45 publications

References 78 publications

Consonant and Vowel Confusions in Well-Performing Children and Adolescents With Cochlear Implants, Measured by a Nonsense Syllable Repetition Test

Consonant and Vowel Confusions in Well-Performing Children and Adolescents With Cochlear Implants, Measured by a Nonsense Syllable Repetition Test

Rhythm processing in cochlear implant−mediated music perception

Perceptual changes with monopolar and phantom electrode stimulation

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