Acoustic voice analysis of prelingually deaf adults before and after cochlear implantation

Vocal control and speech production in cochlear implant listeners: A review within auditory-motor processing framework

A comprehensive literature review is conducted to summarize and discuss prior findings on how cochlear implants (CI) affect the users' abilities to produce and control vocal and articulatory movements within the auditory-motor integration framework of speech. Patterns of speech production pre- versus post-implantation, post-implantation adjustments, deviations from the typical ranges of speakers with normal hearing (NH), the effects of switching the CI on and off, as well as the impact of altered auditory feedback on vocal and articulatory speech control are discussed. Overall, findings indicate that CIs enhance the vocal and articulatory control aspects of speech production at both segmental and suprasegmental levels. While many CI users achieve speech quality comparable to NH individuals, some features still deviate in a group of CI users even years post-implantation. More specifically, contracted vowel space, increased vocal jitter and shimmer, longer phoneme and utterance durations, shorter voice onset time, decreased contrast in fricative production, limited prosodic patterns, and reduced intelligibility have been reported in subgroups of CI users compared to NH individuals. Significant individual variations among CI users have been observed in both the pace of speech production adjustments and long-term speech outcomes. Few controlled studies have explored how the implantation age and the duration of CI use influence speech features, leaving substantial gaps in our understanding about the effects of spectral resolution, auditory rehabilitation, and individual auditory-motor processing abilities on vocal and articulatory speech outcomes in CI users. Future studies under the auditory-motor integration framework are warranted to determine how suboptimal CI auditory feedback impacts auditory-motor processing and precise vocal and articulatory control in CI users.

The Hearing of Erastus "Deaf" Smith, Hero of the Texas Revolution

OBJECTIVES

To describe the speech and hearing abilities of Erastus "Deaf" Smith, the first Texas Ranger, and speculate on the etiology of his hearing loss.

METHODS

Review of credible historical data of what Erastus could and could not hear, descriptions of his voice, and loudness tolerance. Modern analysis of acoustical physics data generated by 0.69-inch diameter non-spinning musket balls.

RESULTS

The onset of Erastus' bilateral hearing loss was early childhood. He could hear some. He was intolerant of very loud sounds. His speech was "weak", "squeaky" and high-pitched. He did not use manual communication. He could not hear musket balls passing near his head. The frequency of sound generated by flying 0.69-inch diameter musket balls has been determined as predominantly in the range of 2000-2500 Hz. In contrast to most bilateral childhood sensorineural hearing losses that are worse in high and mid frequencies, Erastus' hearing loss was worse in the low and mid frequencies - preserving at least some high-frequency hearing.

CONCLUSION

Erastus' reverse-slope hearing problem may well have been attributable to incomplete partition type III. If you can't hear it, you can't speak it.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:3532-3536, 2024.

Impact of cochlear implants use on voice production and quality

Cochlear implant users experience difficulties controlling their vocalizations compared to normal hearing peers. However, less is known about their voice quality. The primary aim of the present study was to determine if cochlear implant users' voice quality would be categorized as dysphonic by the Acoustic Voice Quality Index (AVQI) and smoothed cepstral peak prominence (CPPS). A secondary aim was to determine if vocal quality is further impacted when using bilateral implants compared to using only one implant. The final aim was to determine how residual hearing impacts voice quality. Twenty-seven cochlear implant users participated in the present study and were recorded while sustaining a vowel and while reading a standardized passage. These recordings were analyzed to calculate the AVQI and CPPS. The results indicate that CI users' voice quality was detrimentally affected by using their CI, raising to the level of a dysphonic voice. Specifically, when using their CI, mean AVQI scores were 4.0 and mean CPPS values were 11.4 dB, which indicates dysphonia. There were no significant differences in voice quality when comparing participants with bilateral implants to those with one implant. Finally, for participants with residual hearing, as hearing thresholds worsened, the likelihood of a dysphonic voice decreased.

Comparison the Voice Onset Time (VOT) of Postlingual Cochlear Implant Users and Normal Peers in the CAPE_V Sentences as Continues Speech Task

BACKGROUND

Auditory perception plays a crucial role in speech and language development, emphasizing concerns about hearing loss. While cochlear implantation (CI) nearly tackles challenges associated with postlingual hearing loss in adults, the importance of "auditory feedback" and acoustic assessment becomes crucial for evaluating speech disorders and devising effective treatments. This study aims to address the gap in assessing Voice Onset Time (VOT) as an indicator of nuanced variations in the speech of CI users during a continuous speech task.

METHOD

Recordings of Persian CAPE-V sentences were obtained from 25 CI users and 25 healthy speakers, with a mean age of 33.2years (SD=11.5, range=18-55years). Ten words, incorporating both voiced and voiceless consonants, were selected from the CAPE-V sentences. VOT measurements for the specified stop consonants at the initial syllables of these chosen words were computed using PRAAT. A comparative analysis between the two age- and gender-matched groups was conducted using an independent sample t test. Subsequently, ANCOVA was employed to examine the influence of demographic factors on VOT values among CI participants.

RESULTS

Unvoiced consonant /p/ in /po/, /pɑ/, /pe/, and /pa/ syllables had higher VOT values in the healthy group, while the voiced consonant /d/ in /da/ and /di/ syllables demonstrated higher VOT values in the CI group (P < 0.05). Apart from /po/ and /di/ syllables, no significant impacts of demographic factors on VOT values were observed (P ≥ 0.8).

CONCLUSION

Despite the improvement in speech quality after CI, subtle differences persist. The motor theory, which underscores the impact of auditory inputs on temporal coordination, highlights the role of VOT in speech discrimination. Various linguistic factors affect VOT, including articulation position, vowel context, and raised vowels. While CI enhances syllable distinction, challenges in articulation for adults suggest a need for targeted training in rehabilitation programs, ultimately enhancing the quality of life for CI users.

Comparative Study on the Acoustic Analysis of Voice in Auditory Brainstem Implantees, Cochlear Implantees, and Normal Hearing Children

The aim of the study was to compare the acoustic characteristics of voice between Auditory Brainstem Implantees, Cochlear Implantees and normal hearing children. Voice parameters such as fundamental frequency, formant frequencies, perturbation measures, and harmonic to noise ratio were measured in a total of 30 children out of which 10 were Auditory Brainstem Implantees, 10 were Cochlear Implantees and 10 were normal hearing children. Parametric and nonparametric statistics were done to establish the nature of significance between the three groups. Overall deviancies were seen in the implanted group for all acoustic parameters. However abnormal deviations were seen in individuals with Auditory Brainstem Implants indicating the deficit in the feedback loop impacting the voice characteristics. The deviancy in feedback could attribute to the poor performance in ABI and CI. The CI performed comparatively better when compared to the ABI group indicating a slight feedback loop due to the type of Implant. However, there needs to be additional evidence supporting this and there is a need to carry out the same study using a larger sample size and a longitudinal design.

On the interplay between speech perception and production: insights from research and theories

The study of spoken communication has long been entrenched in a debate surrounding the interdependence of speech production and perception. This mini review summarizes findings from prior studies to elucidate the reciprocal relationships between speech production and perception. We also discuss key theoretical perspectives relevant to speech perception-production loop, including hyper-articulation and hypo-articulation (H&H) theory, speech motor theory, direct realism theory, articulatory phonology, the Directions into Velocities of Articulators (DIVA) and Gradient Order DIVA (GODIVA) models, and predictive coding. Building on prior findings, we propose a revised auditory-motor integration model of speech and provide insights for future research in speech perception and production, focusing on the effects of impaired peripheral auditory systems.

Subjective Voice Handicap and Vocal Tract Discomfort in Patients With Cochlear Implant

OBJECTIVES

Changes in the auditory system, for example due to hearing impairment, can cause changes in breathing, phonation, and articulation. Aim of this study was to provide first data on subjective Voice Handicap and Vocal Tract Discomfort in subjects with hearing impairment and cochlear implant (CI) after initial fitting.

STUDY DESIGN

Prospective cross-sectional study METHODS: A total of 111 participants (57 female and 54 male) between 20 and 85 years of age (mean = 58.21, SD = 14.96) were recruited between October 2019 and March 2020 from the Clinic of Otorhinolaryngology at Medical University of Hannover. Participants were tested after initial CI fitting, six weeks after implantation, using the German version of the VTD (Vocal Tract Discomfort) Scale and VHI (9i) (Voice Handicap Index) as well as speech comprehension tests and a specifically developed questionnaire evaluating data concerning voice usage and other influential factors. Statistics included descriptive analysis, group comparisons (t-Test), Pearson correlation coefficient between VTD Scale and VHI, and hearing status.

RESULTS

Patients with CI did show low scores in VTD Scale and VHI-9i (VTD mean = 7.85 [SD = 10.4]; VHI-9i mean = 4.04 [SD = 5.77]). We found neither a correlation between any of the speech comprehension tests and the VTD Scale nor the VHI-9i. Further, we could show no correlation between subjective Voice Handicap and/or Vocal Tract Discomfort and age or the kind of treatment.

CONCLUSION

Patients included in this study did not show more subjective Voice Handicap or Vocal Tract Discomfort than normal hearing peers. Scores of VTD Scale and VHI-9i did not depend on the duration of hearing loss, speech comprehension, kind of treatment or age.

Quality of Voice in Patients With Partial Deafness Before and After Cochlear Implantation

Partial deafness is a condition characterised by normal hearing thresholds in low frequencies and increased hearing thresholds (nearly deafness) for high frequencies. Typical hearing aids are rather of a very limited use in this condition as they do not improve understanding of speech. Patients with partial deafness can be presently treated with cochlear implants, which had not been used before due to the risk of damage of hearing remains by electrode introduced into cochlea. The purpose of our study was an objective and subjective assessment of voice quality in partial deafness patients before and after cochlear implantation. The subjects in this study were 25 post-lingual, bilaterally partially deaf patients, 13 females and 12 males. The reference group composed of 55 normal hearing individuals (28 females and 27 males). The acoustic analysis was performed with a multidimensional voice analysis MDVP (Multi Dimension Voice Program), and the subjective assessment was done with GRBAS scale. Initial analysis of voice changes in partial deafness patients was performed versus normal hearing individuals, then voice parameters were measured and perceptual voice assessment was done before and 9 months after cochlear implantation. Measurements of acoustic voice parameters in partially deaf patients showed changes in most of frequency, amplitude, noise and subharmonic components versus normal hearing control group. The most significant, statistically important changes were observed in fundamental frequency variation (vF0), absolute jitter (Jita), jitter percent (Jitt), amplitude perturbation quotient (APQ), smoothed amplitude perturbation quotient (sAPQ), relative average perturbation (RAP), peak amplitude variation (vAm), relative amplitude modulation (Shim), percent shimmer (%Shim), pitch perturbation quotient (PPQ), smoothed pitched perturbation quotient (sPPQ), degree of subharmonics (DSH), degree of voiceless (DUV), number of subharmonic segments (NSH), noise-to-harmonic ratio (NHR), voice turbulence index (VTI). All patients in the study group were subjects to cochlear implantation. After 9 months objective and subjective assessment of patients` voices were performed again. Statistically important changes were identified in average fundamental frequency variability (vF0), relative amplitude modulation index (ShdB), noise-to-harmonic ratio (NHR), number of subharmonics NSH, degree of subharmonics (DSH) and the degree of voiceless (DUV). Comparison of the objective voice parameters changes after cochlear implantation with subjective, perceptual voice quality assessments leads to observation, that improvement of subjective voice quality after cochlear implantation takes place parallelly with improvement of certain objective acoustic voice parameters and some correlations exist. We found, that G correlates with vF0 and Shim, R correlates with DSH and NSH, B correlates with NSH and NHR, A correlates with DUV. We did not prove correlation of S with any of the objective parameters in our research group. Our study proved, that acoustic and perceptual features of voice in partially deaf adults are different than in normally hearing people and cochlear implantation in partial deafness patients is an effective tool to improve hearing and leads to improvement of the acoustic structure of the voice.Partial deafness is a condition characterised by normal hearing thresholds in low frequencies and increased hearing thresholds (nearly deafness) for high frequencies. Typical hearing aids are rather of a very limited use in this condition as they do not improve understanding of speech. Patients with partial deafness can be presently treated with cochlear implants, which had not been used before due to the risk of damage of hearing remains by electrode introduced into cochlea. The purpose of our study was an objective and subjective assessment of voice quality in partial deafness patients before and after cochlear implantation. The subjects in this study were 25 post-lingual, bilaterally partially deaf patients, 13 females and 12 males. The reference group composed of 55 normal hearing individuals (28 females and 27 males). The acoustic analysis was performed with a multidimensional voice analysis MDVP (Multi Dimension Voice Program), and the subjective assessment was done with GRBAS scale. Initial analysis of voice changes in partial deafness patients was performed versus normal hearing individuals, then voice parameters were measured and perceptual voice assessment was done before and 9 months after cochlear implantation. Measurements of acoustic voice parameters in partially deaf patients showed changes in most of frequency, amplitude, noise and subharmonic components versus normal hearing control group. The most significant, statistically important changes were observed in fundamental frequency variation (vF0), absolute jitter (Jita), jitter percent (Jitt), amplitude perturbation quotient (APQ), smoothed amplitude perturbation quotient (sAPQ), relative average perturbation (RAP), peak amplitude variation (vAm), relative amplitude modulation (Shim), percent shimmer (%Shim), pitch perturbation quotient (PPQ), smoothed pitched perturbation quotient (sPPQ), degree of subharmonics (DSH), degree of voiceless (DUV), number of subharmonic segments (NSH), noise-to-harmonic ratio (NHR), voice turbulence index (VTI). All patients in the study group were subjects to cochlear implantation. After 9 months objective and subjective assessment of patients` voices were performed again. Statistically important changes were identified in average fundamental frequency variability (vF0), relative amplitude modulation index (ShdB), noise-to-harmonic ratio (NHR), number of subharmonics NSH, degree of subharmonics (DSH) and the degree of voiceless (DUV). Comparison of the objective voice parameters changes after cochlear implantation with subjective, perceptual voice quality assessments leads to observation, that improvement of subjective voice quality after cochlear implantation takes place parallelly with improvement of certain objective acoustic voice parameters and some correlations exist. We found, that G correlates with vF0 and Shim, R correlates with DSH and NSH, B correlates with NSH and NHR, A correlates with DUV. We did not prove correlation of S with any of the objective parameters in our research group. Our study proved, that acoustic and perceptual features of voice in partially deaf adults are different than in normally hearing people and cochlear implantation in partial deafness patients is an effective tool to improve hearing and leads to improvement of the acoustic structure of the voice.

Systematic Review of Auditory Perceptual and Acoustic Characteristics of the Voice of Cochlear Implant Adult Users

STATEMENT OF PROBLEM

What are the normative data available on the perceptual and acoustic characteristics of the voice of adults of both sexes who have hearing-impairment and who use cochlear implants?

PURPOSE

To identify in the literature, normative data about the perceptual auditory and acoustic characteristics of the voice of hearing-impaired cochlear implant adult users.

SEARCH STRATEGY

A systematic search was carried out in the Virtual Health Library, Web of Science, Science Direct, SciELO, and SCOPUS databases with no temporal restriction.

SELECTION CRITERIA

The articles were selected if they led with citation to normative data of the acoustic analysis of the voice of deaf cochlear implant users. And duplicate articles, case studies, letters to the editor, reviews, and studies that were not directly related to the topic were excluded.

DATA EXTRACTION

The data from each article were extracted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis checklist: title, abstract, year of publication, journal, authors and country of origin, identification of background, purpose, study design, participants, variables, and data measurement.

DATA SYNTHESIS

There were 1,052 publications that met the search criteria. After applying the Preferred Reporting Items for Systematic Reviews and Meta-analysis checklist, excluding duplicates, and reading of the full text, 10 papers were selected for further analysis. Although several voice parameters have been studied, there is a great variation in study designs, sample sizes, age of participants, voice samples analyzed, and cochlear implant specifications.

CONCLUSION

The normative data available in the literature concerning the voice of cochlear implant users are consistent only in terms of fundamental frequency.

Influence of bilateral cochlear implants on vocal control

Receiving a cochlear implant (CI) can improve fundamental frequency (F0) control for deaf individuals, resulting in increased vocal pitch control. However, it is unclear whether using bilateral CIs, which often result in mismatched pitch perception between ears, will counter this benefit. To investigate this, 23 bilateral CI users were asked to produce a sustained vocalization using one CI, the other CI, both CIs, or neither. Additionally, a set of eight normal hearing participants completed the sustained vocalization task as a control group. The results indicated that F0 control is worse with both CIs compared to using the ear that yields the lowest vocal variability. The results also indicated that there was a large range of F0 variability even for the relatively stable portion of the vocalization, spanning from 6 to 46 cents. These results suggest that bilateral CIs can detrimentally affect vocal control.

Effect of the Finnish Tube on the Voice of a Deaf Musician: A Case Report

PURPOSE

To verify the auditory-perceptual and acoustic effects of the semioccluded vocal tract exercise with Finnish tube on the vocal quality of a deaf musician.

METHODS

A seven-day protocol with Finnish tube was performed with guidance for its home replication twice a day. A 46-years-old man with profound bilateral sensorineural hearing loss, musician and composer participated. Before and after the application of the protocol had undergone tonal audiometry, nasofibrolaryngoscopy, acoustic analysis with Praat and auditory-perceptual evaluation of the voice with Voice Profile Analysis Scheme for Brazilian Portuguese.

RESULTS

The postintervention auditory-perceptual analysis identified reduction of the deviation in lip spreading, extensive labial range, raised tongue body, pharyngeal expansion, nasal resonance, larynx height, larynx and vocal tract tension and irregularity, pitch, speech rate, and a better respiratory support. The maximum phonation time reduced, probably because of elimination of the abrupt vocal attack and tension, articulatory deviations, improvement in voicing and the absence of the use of expiratory reserve air. The fundamental frequency became lower, and the first, second, third, and fourth formants became higher. The jitter increased, and the shimmer reduced.

CONCLUSION

The use of the Finnish tube might have facilitated the voicing sensations in the deaf musician, by enhancing the tactile-kinesthetic perception of the vocal tract and brought a greater source-filter interaction.

Basic Measures of Prosody in Spontaneous Speech of Children With Early and Late Cochlear Implantation

PURPOSE

Relative to normally hearing (NH) peers, the speech of children with cochlear implants (CIs) has been found to have deviations such as a high fundamental frequency, elevated jitter and shimmer, and inadequate intonation. However, two important dimensions of prosody (temporal and spectral) have not been systematically investigated. Given that, in general, the resolution in CI hearing is best for the temporal dimension and worst for the spectral dimension, we expected this hierarchy to be reflected in the amount of CI speech's deviation from NH speech. Deviations, however, were expected to diminish with increasing device experience.

METHOD

Of 9 Dutch early- and late-implanted (division at 2 years of age) children and 12 hearing age-matched NH controls, spontaneous speech was recorded at 18, 24, and 30 months after implantation (CI) or birth (NH). Six spectral and temporal outcome measures were compared between groups, sessions, and genders.

RESULTS

On most measures, interactions of Group and/or Gender with Session were significant. For CI recipients as compared with controls, performance on temporal measures was not in general more deviant than spectral measures, although differences were found for individual measures. The late-implanted group had a tendency to be closer to the NH group than the early-implanted group. Groups converged over time.

CONCLUSIONS

Results did not support the phonetic dimension hierarchy hypothesis, suggesting that the appropriateness of the production of basic prosodic measures does not depend on auditory resolution. Rather, it seems to depend on the amount of control necessary for speech production.

Cochlear Implant Users' Vocal Control CorrelatesAcross Tasks

Cochlear implants (CIs) provide access to auditory information that can affect vocal control. For example, previous research shows that, when producing a sustained vowel, CI users will alter the pitch of their voice when the feedback of their own voice is perceived to shift. Although these results can be informative as to how perception and production are linked for CI users, the artificial nature of the task raises questions as to the applicability of the results to real-world vocal productions. To examine how vocal control, when producing sustained vowels, relates to vocal control for more ecologically valid tasks, 10 CI users' vocal control was measured across two tasks: (1) sustained vowel production, and (2) singing. The results found that vocal control, as measured by the variability of the participants' fundamental frequency, was significantly correlated when producing sustained vowels and when singing, although variability was significantly greater when singing. This suggests that, despite the artificial nature of sustained vowel production, vocal control on such tasks is related to vocal control for more ecologically valid tasks. However, the results also suggest that vocal control may be overestimated with sustained vowel production tasks.

When singing with cochlear implants, are two ears worse than one for perilingually/postlingually deaf individuals?

Many individuals with bilateral cochlear implants hear different pitches when listening with their left versus their right cochlear implant. This conflicting information could potentially increase the difficulty of singing with cochlear implants. To determine if bilateral cochlear implants are detrimental for singing abilities, ten perilingually/postlingually deaf bilateral adult cochlear implant users were asked to sing "Happy Birthday" when using their left, right, both, or neither cochlear implant. The results indicated that bilateral cochlear implant users have more difficulty singing the appropriate pitch contour when using both cochlear implants as opposed to the better ear alone.

Long-term Average Speech Spectra of Postlingual Cochlear Implant Users

Long term average speech spectra (LTASS) is a commonly used voice analysis method for different purposes. This method offers an acoustic representation of the language in daily conservations. Results of that method can be altered by the deteriorations in the auditory feedback loop. Hearing losses occurred in the post lingual stage of life have some serious negative effects on the auditory feedback loop. Cochlear implantation may help these patients with regards to auditory feedback loop. Therefore, we aimed to evaluate the LTASS of cochlear implant users whose have a post lingual hearing loss. We assessed the LTASS of 24 cochlear implant users and compared our findings with normal hearing subjects. Our findings revealed that cochlear implant users have similar LTASS findings with normal hearing subjects. We conclude that cochlear implantation helps to the recovery of auditory feedback loop in patients with post lingual hearing losses.

Period for Normalization of Voice Acoustic Parameters in Indian Pediatric Cochlear Implantees

OBJECTIVE

The purpose of this study was to investigate the duration required by children with cochlear implants to approximate the norms of voice acoustic parameters.

STUDY DESIGN

The study design is retrospective.

METHODS

Thirty children with cochlear implants (chronological ages ranging between 4.1 and 6.7 years) were divided into three groups, based on the postimplantation duration. Ten normal-hearing children (chronological ages ranging between 4 and 7 years) were selected as the control group. All implanted children underwent an objective voice analysis using Dr. Speech software (Tiger DRS, Inc., Seattle, WA, USA) at 6 months and at 1 and 2 years of implant use. Voice analysis was done for the children in the control group and means were derived for all the parameters analyzed to obtain the normal values. Habitual fundamental frequency (HFF), jitter (frequency variation), and shimmer (amplitude variation) were the voice acoustic parameters analyzed for the vowels |a|, |i|, and |u|. The obtained values of these parameters were then compared with the norms.

RESULTS

HFF for the children with implant use for 6 months and 1 year did significantly differ from the control group. However, there was no significant difference (P > 0.5) observed in the children with implant use for 2 years, thus matching the norms. Jitter and shimmer showed a significant difference (P < 0.5) even at 2 years of implant use when compared with the control group.

CONCLUSIONS

The findings of the study divulge that children with cochlear implants approximate age-matched normal-hearing kids with respect to the voice acoustic parameter of HFF by 2 years of implant use. However, jitter and shimmer were not found to stabilize for the duration studied.

Hearing performance and voice acoustics of cochlear implanted children

INTRODUCTION

The voice of hearing-impaired individuals has been described extensively, and exhibits abnormalities in quality, articulation and resonance. Having an understanding of the aspects that may have an impact on voice characteristics of cochlear implant users is important for users and for professionals in this field.

OBJECTIVE

To verify the existence of correlation between age, time of device use, voice detection threshold, hearing category score and language category score with acoustic data of voices of cochlear implanted children.

METHODS

Retrospective study. Fifty-one children ranging in age from 3 years to 5 years and 11 months who unilaterally used cochlear implants participated. Acoustic analysis of the sustained vowel/a/, sequential speech and spontaneous speech was performed. The results were correlated with demographic data and hearing test results.

RESULTS

Children with worse voice detection threshold showed higher frequency in the sustained vowel (p≤0.001) and in the spontaneous speech (p≤0.005).

CONCLUSION

There was a correlation between the voice detection threshold and the frequency values of the sustained vowel and spontaneous speech of the studied population.

Nasalance in Cochlear Implantees

Objectives

Speech intelligibility is severely affected in children with congenital profound hearing loss. Hypernasality is a problem commonly encountered in their speech. Auditory information received from cochlear implants is expected to be far superior to that from hearing aids. Our study aimed at comparing the percentages of nasality in the speech of the cochlear implantees with hearing aid users and also with children with normal hearing.

Methods

Three groups of subjects took part in the study. Groups I and II comprised 12 children each, in the age range of 4-10 years, with prelingual bilateral profound hearing loss, using multichannel cochlear implants and digital hearing aids respectively. Both groups had received at least one year of speech therapy intervention since cochlear implant surgery and hearing aid fitting respectively. The third group consisted of age-matched and sex-matched children with normal hearing. The subjects were asked to say a sentence which consisted of only oral sounds and no nasal sounds ("Buy baby a bib"). The nasalance score as a percentage was calculated.

Results

Statistical analysis revealed that the children using hearing aids showed a high percentage of nasalance in their speech. The cochlear implantees showed a lower percentage of nasalance compared to children using hearing aids, but did not match with their normal hearing peers.

Conclusion

The quality of speech of the cochlear implantees was superior to that of the hearing aid users, but did not match with the normal controls. The study suggests that acoustic variables still exist after cochlear implantation in children, with hearing impairments at deviant levels, which needs attention. Further research needs to be carried out to explore the effect of the age at implantation as a variable in reducing nasality in the speech and attaining normative values in cochlear implantees, and also between unilateral versus bilateral implantees.

Exploring consequences of short- and long-term deafness on speech production: a lip-tube perturbation study

Studies have reported strong links between speech production and perception. We aimed to evaluate the role of long- and short-term auditory feedback alteration on speech production. Eleven adults with normal hearing (controls) and 17 cochlear implant (CI) users (7 pre-lingually deaf and 10 post-lingually deaf adults) were recruited. Short-term auditory feedback deprivation was induced by turning off the CI or by providing masking noise. Acoustic and articulatory measures were obtained during the production of /u/, with and without a tube inserted between the lips (perturbation), and with and without auditory feedback. F1 values were significantly different between the implant OFF and ON conditions for the pre-lingually deaf participants. In the absence of auditory feedback, the pre-lingually deaf participants moved the tongue more forward. Thus, a lack of normal auditory experience of speech may affect the internal representation of a vowel.

Nasalance and nasality in children with cochlear implants and children with hearing aids

OBJECTIVES

In prelingually deaf children, many speech production aspects including resonance, are known to be problematic. This study aimed to investigate nasality and nasalance in two groups of prelingually hearing impaired children, namely deaf children with a cochlear implant (CI) and moderate-to-severely hearing impaired hearing aid (HA) users. The results of both groups are compared with the results of normal hearing children. Besides, the impact of the degree of hearing loss was determined.

METHODOLOGY

36 CI children (mean age: 9;0y), 25 HA children (mean age: 9;1y) and 26 NH children (mean age: 9;3y) were assessed using objective assessment techniques and perceptual evaluations in order to investigate the nasal resonance of the three groups. Ten HA children had thresholds above 70dB (range: 91dB-105dB) and fifteen below 70dB (range: 58dB-68dB). The Nasometer was used for registration of the nasalance values and nasality was perceptually evaluated by two experienced speech therapists using a nominal rating scale (consensus evaluation).

RESULTS

For nasal stimuli, both CI children and HA children showed lower nasalance values in comparison with NH children. The opposite was observed for the oral stimuli. In both hearing impaired groups, cul-de-sac-resonance was observed on a significantly larger scale than in the NH group, and the HA children were judged to be significantly more hypernasal in comparison with NH children.

CONCLUSIONS

Despite the fact that a substantial number of the CI and HA children demonstrate normal (nasal) resonance quality, this aspect of speech production is still at risk for hearing impaired children.

An initial study of voice characteristics of children using two different sound coding strategies in comparison to normal hearing children

OBJECTIVE

To compare some perceptual and acoustic characteristics of the voices of children who use the advanced combination encoder (ACE) or fine structure processing (FSP) speech coding strategies, and to investigate whether these characteristics differ from children with normal hearing.

DESIGN

Acoustic analysis of the sustained vowel /a/ was performed using the multi-dimensional voice program (MDVP). Analyses of sequential and spontaneous speech were performed using the real time pitch. Perceptual analyses of these samples were performed using visual-analogic scales of pre-selected parameters.

STUDY SAMPLE

Seventy-six children from three years to five years and 11 months of age participated. Twenty-eight were users of ACE, 23 were users of FSP, and 25 were children with normal hearing.

RESULTS

Although both groups with CI presented with some deviated vocal features, the users of ACE presented with voice quality more like children with normal hearing than the users of FSP.

CONCLUSIONS

Sound processing of ACE appeared to provide better conditions for auditory monitoring of the voice, and consequently, for better control of the voice production. However, these findings need to be further investigated due to the lack of comparative studies published to understand exactly which attributes of sound processing are responsible for differences in performance.

Systematic analysis of the benefits of cochlear implants on voice production

PURPOSE

To perform a systematic analysis of the research regarding vocal characteristics of hearing impaired children or adults with cochlear implants.

RESEARCH STRATEGY

A literature search was conducted in the databases Web of Science, Bireme, and Universidade de São Paulo's and CAPES' thesis and dissertations databases using the keywords voice, voice quality, and cochlear implantation, and their respective correspondents in Brazilian Portuguese.

SELECTION CRITERIA

The selection criteria included: title consistent with the purpose of this review; participants necessarily being children or adults with severe to profound pre-lingual or post-lingual hearing loss using cochlear implants; and data regarding participants' performance on perception and/or acoustic analysis of the voice.

RESULTS

Twenty seven papers were classified according to the levels of evidence and quality indicators recommended by the American Speech-Language-Hearing Association (ASHA). The designs of the studies were considered of low and medium levels of evidence. Six papers were classified as IIb, 20 as III, and one as IV.

CONCLUSION

The voice of hearing impaired children and adults with cochlear implants has been little studied. There is not an effective number of studies with high evidence levels which precisely show the effects of the cochlear implantation on the quality of voice of these individuals.

Characteristics of nasal resonance and perceptual rating in prelingual hearing impaired adults

Objectives

Resonance problems in hearing impaired (HI) individuals have been described as aspects of nasality. However, there are limitations in being able to explain the range of resonance problems. Therefore, this study suggests a perceptual rating that will effectively explain the characteristics of resonance problems in HI individuals.

Methods

Nasalance scores were obtained from 32 subjects in each of HI and normal hearing (NH) groups using a nasometer. The subjects were categorized into groups based on normal and abnormal nasalance ranges. The abnormal nasalance range group was further divided into hyper-, hypo-, and mixed-nasal groups. Nasalance scores were based the individuals performance in a series of passage and syllable tasks. The perceptual rating was evaluated using a newly introduced tool, 'vertical focus of resonance' (VFR), which focuses on the resonance energy in the frontal, throat, pharyngeal and nasal locations.

Results

The NH group demonstrated a significantly lower nasalance score in the oral coupling and passage tasks than the HI group. Based on the results of nasalance correlation analysis, the HI group showed highly significant correlations between syllable and passage tasks, as contrasted with the NH group. There were significant differences in VFR between the nasalance types in both the NH and the HI groups.

Conclusion

The HI hyper-nasal group showed tendencies of velopharyngeal opening, as opposed to the HI hypo-nasal group which showed tendencies of velopharyngeal closure. The HI mixed-nasal group showed inappropriate coordination of velopharyngeal function. In the HI group, the results of VFR showed that the air flow and the resonance energy were not released from the cavity of resonance. The suggested VFR tool explains the focusing characteristics of resonance energy within a continuation of speech sound regardless of the phonetic environment. Therefore, VFR may be a useful tool in explaining the deviant resonance patterns of HI individuals.

Classification of voice disorder in children with cochlear implantation and hearing aid using multiple classifier fusion

Background

Speech production and speech phonetic features gradually improve in children by obtaining audio feedback after cochlear implantation or using hearing aids. The aim of this study was to develop and evaluate automated classification of voice disorder in children with cochlear implantation and hearing aids.

Methods

We considered 4 disorder categories in children's voice using the following definitions:

Level_1: Children who produce spontaneous phonation and use words spontaneously and imitatively.

Level_2: Children, who produce spontaneous phonation, use words spontaneously and make short sentences imitatively.

Level_3: Children, who produce spontaneous phonations, use words and arbitrary sentences spontaneously.

Level_4: Normal children without any hearing loss background. Thirty Persian children participated in the study, including six children in each level from one to three and 12 children in level four. Voice samples of five isolated Persian words "mashin", "mar", "moosh", "gav" and "mouz" were analyzed. Four levels of the voice quality were considered, the higher the level the less significant the speech disorder. "Frame-based" and "word-based" features were extracted from voice signals. The frame-based features include intensity, fundamental frequency, formants, nasality and approximate entropy and word-based features include phase space features and wavelet coefficients. For frame-based features, hidden Markov models were used as classifiers and for word-based features, neural network was used.

Results

After Classifiers fusion with three methods: Majority Voting Rule, Linear Combination and Stacked fusion, the best classification rates were obtained using frame-based and word-based features with MVR rule (level 1:100%, level 2: 93.75%, level 3: 100%, level 4: 94%).

Conclusions

Result of this study may help speech pathologists follow up voice disorder recovery in children with cochlear implantation or hearing aid who are in the same age range.