The Effect of Auditory Input on the Rate of Speech Production by Cochlear Implant Users
The Effect of Auditory Input on the Rate of Speech Production by Cochlear Implant Users

Author: Sujin Shin

Publisher:

Published: 2018

Total Pages:

ISBN-13:

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Children with cochlear implants (CIs) present with slower speech than their typical hearing (TH) peers. The slowed speaking rate of children with CIs has received recent attention due to the relation of speaking rate with working memory and with speech intelligibility. However, the underlying causes for the slowed speech of CI recipients are not fully understood. In this thesis, three theoretical explanations are introduced to understand how degraded auditory input affects the timing of speech. First, children with CIs may have slowed speech due to an immature internal model caused by degraded auditory feedback and the lack of auditory input. Second, the speech of children with CIs may become slower because either all or a part of speech processing stages are slowed. Third, the slowed speech of children with CIs may be influenced by paralinguistic factors, such as the intention to speak more clearly. To explore the reasons for the slowed speech of CI recipients, three experiments were performed. A first experiment explored the effects of chronological factors (such as age of implant and duration of CI experience) and performance factors (such as language ability and speech perception) on the speaking rates of 75 children with CIs and 54 children with TH at four to eight years after implantation. Results showed that speaking rate was significantly slower in the CI group than the TH group, confirming previous reports. Maturation and the amount of the auditory input were important to speaking rate, supporting the immature internal model hypothesis. Out of performance factors, language ability was the best predictor of the speaking rate of children with CIs, suggesting that the speed and accuracy of linguistic processing may be a key to the slowed speech of children with CIs. A second experiment explored whether the slowed speaking rate of children with CIs results from impairments at particular linguistic levels (lexical, syntactic, phonetic/articulatory) of speech processing and whether the speaking rates at these levels are related to working memory. Results indicated that the speaking rates of participants with CIs showed the greatest reduction compared to their TH counterparts when engaged in syntactic level processing. Also, the speaking rates for the syntactic task showed the strongest relationship with children’s memory span, suggesting syntactic processing could be an important factor in the relation between speaking rate and memory. A third experiment investigated whether paralinguistic factors are involved in the slowed speech of children with CIs. Twelve teenagers with CIs and twelve counterparts with TH were asked to repeat short sentences “as fast as possible,” at their habitual speed, and “slowly and clearly.” Results showed that participants with CIs were able to increase their rate but their rate changes for the slow/clear condition was not statistically significant, suggesting that the slowed speech of participants with CIs may be due to strategic choice, rather than cognitive or physical limitations. Overall, the results of these three experiments suggest that the slowed speech of CI recipients are influenced by multiple factors, including maturation, CI experience, and linguistic and paralinguistic components. Implications for clinical practice are discussed.

Hearing Loss
Hearing Loss

Author: National Research Council

Publisher: National Academies Press

Published: 2004-12-17

Total Pages: 321

ISBN-13: 0309092965

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Millions of Americans experience some degree of hearing loss. The Social Security Administration (SSA) operates programs that provide cash disability benefits to people with permanent impairments like hearing loss, if they can show that their impairments meet stringent SSA criteria and their earnings are below an SSA threshold. The National Research Council convened an expert committee at the request of the SSA to study the issues related to disability determination for people with hearing loss. This volume is the product of that study. Hearing Loss: Determining Eligibility for Social Security Benefits reviews current knowledge about hearing loss and its measurement and treatment, and provides an evaluation of the strengths and weaknesses of the current processes and criteria. It recommends changes to strengthen the disability determination process and ensure its reliability and fairness. The book addresses criteria for selection of pure tone and speech tests, guidelines for test administration, testing of hearing in noise, special issues related to testing children, and the difficulty of predicting work capacity from clinical hearing test results. It should be useful to audiologists, otolaryngologists, disability advocates, and others who are concerned with people who have hearing loss.

Artificial Hearing, Natural Speech
Artificial Hearing, Natural Speech

Author: Joanna Hart Lowenstein

Publisher: Routledge

Published: 2013-09-13

Total Pages: 161

ISBN-13: 1135922349

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This book explores the interface between speech perception and production through a longitudinal acoustic analysis of the speech of postlingually deaf adults with cochlear implants (electrode and computer prostheses for the inner ear in cases of nerve deafness). The methodology is based on the work of Joseph Perkell at MIT, replicating and extending analysis to subjects with modern digital cochlear implants and processor technology. Lowenstein also examines how cochlear implants are portrayed in dramatic and documentary television programs, the scientific accuracy of those portrayals, and what expectations might be taken away by viewers, particularly given modern society's view that technology can overcome the frailties of the human body.

Lombard Effect in Speech Production by Cochlear Implant Users
Lombard Effect in Speech Production by Cochlear Implant Users

Author: Jaewook Lee

Publisher:

Published: 2017

Total Pages:

ISBN-13:

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In daily communication, speakers aim to communicate their message in a manner that is intelligible to listeners. When individuals with normal hearing become aware of reduced auditory feedback due to environmental noise, they likely adopt a different speaking style called the ‘Lombard effect’. The Lombard effect is the tendency of speakers to modify their speech production while speaking in the presence of loud noise. Increased levels of masking noise lead to increase in vocal effort including energy, fundamental frequency, and glottal spectral slope. Lombard speech modification is aimed at providing the listener with increased speech intelligibility in challenging listening environments. The Lombard effect is also known to degrade automatic speech systems such as automatic speech recognition (ASR) and speaker identification (SID). While well-studied for normal hearing listeners and automatic speech systems, the Lombard effect has received little, if any, attention in the field of cochlear implant users. To our knowledge, no study has examined whether cochlear implant users employ the Lombard effect during voice communication. This dissertation provided a comprehensive investigation of the research concerning Lombard effect for cochlear implant users with post-lingual deafness. We investigated the nature of the Lombard effect that was produced by cochlear implant users. A variety of acoustic and phonetic features including voice power, fundamental frequency, glottal spectral tilt, phoneme duration, and formant frequencies were analyzed. Mobile personal audio recordings from continuous single-session audio streams collected over an individual’s daily life were used for these analyses. Prior advancements in this domain include the “Prof-Life-Log”longitudinal study at UT-Dallas. The Lombard effect was observed in the speech production of all cochlear implant users. The results indicate that both suprasegmental ( e.g., F0, glottal spectral slope and vocal intensity) and segmental (e.g., F1 for /i/ and /u/)) features were altered in such environments. Along with speech production characteristics, the research also focused on the effect of Lombard speaking style on intelligibility by cochlear implant users. A speech corpus for the perceptual experiments of Lombard speech was formulated with normal hearing speakers. A subjective listening test was performed to provide how cochlear implant users respond to Lombard speech in challenging listening environments. The results indicate that the Lombard speech yielded a significant improvement in intelligibility in both quiet and noisy listening conditions. The specific modification of speech production of cochlear implant users under the Lombard effect may contribute to some degree an intelligible communication in adverse noisy environments. Lastly, a practical implication of Lombard effect for developing a speech enhancement algorithm for cochlear implant users was discussed. A previous proposed framework based on Source Generator theory was employed to perturb neutral speech production based on Lombard effect modification. Data from subjective evaluation demonstrated the effectiveness of the proposed speech enhancement algorithm. The results indicated improvement in intelligibility when providing neutral speech which was modified based on Lombard effect properties via the proposed algorithm. The specific variations due to Lombard effect can be leveraged for new algorithm development and further applications of speech technology to benefit cochlear implant users.

An Examination of the Influence of the Nucleus and Clarion Multichannel Cochlear Implants on Speech Production [microform]
An Examination of the Influence of the Nucleus and Clarion Multichannel Cochlear Implants on Speech Production [microform]

Author: Kim Zimmerman

Publisher: National Library of Canada = Bibliothèque nationale du Canada

Published: 1998

Total Pages: 143

ISBN-13: 9780612307452

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This study investigated the effect of Nucleus and Clarion multichannel cochlear implant use on the speech production of adults with a severe to profound hearing impairment. Specifically, this experiment was designed to ascertain the impact of cochlear implant use on the acoustical characteristics of speech including first vowel formant frequency and second vowel formant frequency. Ten monosyllabic stimuli were used to collect speech samples. The acoustic samples were then analyzed using the CSpeech software package. The data for each subject were assessed using a single-subject experimental design $\rm(A\sb1BCA\sb2)$ which included measures of central tendency and other quantitative analyses. Substantial variability was found across the acoustic parameters. The amount of variability, however, differed for each subject, and all acoustic parameters were not equally affected. Although there was a large amount of individual subject variability, common trends were also noted among subjects. These trends included F$\sb1$ values that more closely approximated the normative values of Peterson and Barney (1952) than F$\sb2$ values, F$\sb2$ values for back and central vowels that exceeded Peterson and Barney's normative data, and F$\sb2$ values for front vowels that were below Peterson and Barney's (1952) normative values. The data suggest that cochlear implant recipients may use the auditory feedback provided by the implant to monitor and adjust their speech output. It was proposed that such modifications, if indeed they did occur, are due to changes in the length and shape of the vocal tract. Specifically, changes in the anterior oral, posterior oral and pharyngeal cavities.

The Auditory Processing of Speech
The Auditory Processing of Speech

Author: Marten E. Schouten

Publisher: Walter de Gruyter

Published: 2011-08-30

Total Pages: 393

ISBN-13: 3110879018

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A message from a speaker to a listener has to travel a very long way, from an intention on the part of the former, via an acoustic signal, through the transducer stages of the peripheral auditory system. The present book is about the listener. It consists of 35 papers by researchers from a limited number of related fields between the auditory periphery and word recognition, who met in 1991.

Leveraging Landmark Acoustic Features in Cochlear Implant Signal Processing
Leveraging Landmark Acoustic Features in Cochlear Implant Signal Processing

Author: Juliana N. Saba

Publisher:

Published: 2021

Total Pages: 0

ISBN-13:

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Document abstract changed to 'The Lombard Effect (LE), defined as acoustic changes in speech production due to auditory feedback from the speaker's acoustic environment, has been shown to improve intelligibility in normal hearing and some hearing-impaired listeners. However, LE has not been investigated specifically for cochlear implant systems and users. For CI users, signal processing strategies generate an electric representation of the acoustic signal which has enabled high speech understanding performance in quiet conditions but declines in the presence of naturalistic noisy environments. In this thesis, a range of signal processing approaches are proposed to improve electric stimulation by influencing channel selection based on salient speech features and to leverage the acoustic properties of Lombard speech as a means to improve intelligibility for CI users in difficult listening scenarios. Traditional 'n'-of-'m' processing strategies utilize an energybased channel selection criteria to select 'n' out of 'm' available channels corresponding to the intracochlear electrode array. For speech-in-noise scenarios, noise-dominant channels may be selected at the expense of speech frequency-rich channels carrying important phonetic cues. For quiet listening scenarios, low-level consonant energy may be overshadowed by higher-level channels. To overcome these challenges, a formant-based channel selection scheme is used to determine the effect on channel selection and speech intelligibility. This approach is hypothesized to illicit minor yet strategic changes in the electric representation of speech to include formant frequency information in the presence of noise. Second, two apriori compression functions are proposed to increase the intensity of formants and consonant segments. Lastly, three proposed speech modification strategies inspired by Lombard speech are introduced. The ability of CI listeners to perceive LE, the benefits of LE perturbation of neutral input speech, and the effect of semantics on LE perturbation are all addressed. These perturbation approaches are hypothesized to illicit large, meaningful changes in the electric representation by altering the following changes in the speech structure: intensity, first formants and second formant location/amplitude/bandwidth, long-term average spectrum, fundamental frequency, and individual phoneme class duration. We demonstrate the implications of CI listeners to leverage salient features Lombard speech and examine the feasibility of Lombard perturbation to improve speech understanding for CI users.'