Control of speech and voice in cochlear implant patients

A meta-analysis of expressive prosody in cochlear implant users

INTRODUCTION

Prosody is used to express indexical (identifying the talker), linguistic (e.g., question intonation, lexical stress), pragmatic (e.g., contrastive stress, sarcasm), and emotional/affective functions. It is manifested through changes in fundamental frequency (f0), intensity, and duration. F0 and intensity are degraded when perceived through a cochlear implant (CI). The purpose of this meta-analysis is to compare expressive prosody in speech produced by CI users versus normal hearing peers.

METHODS

A systematic search of the literature found 25 articles that met all inclusion criteria. These articles were assessed for quality, and data pertaining to the expression of f0, intensity, and duration, as well as classification accuracy and appropriateness ratings from normal hearing listeners, were extracted and meta-analyzed using random effects models.

RESULTS

The articles included in the meta-analysis were generally of acceptable or high quality. Meta-analyses revealed significant differences between individuals with CIs vs. normal hearing on all measures except mean f0, mean intensity, and rhythm. Effect sizes were generally medium to large. There was significant heterogeneity across studies, but little evidence of publication bias.

CONCLUSIONS

CI users speak with less variable f0, smaller f0 contours, more variable intensity, a slower speech rate, and reduced final lengthening at syntactic boundaries. These acoustic differences are reflected in significantly poorer ratings of speech produced by CI users compared to their normal hearing peers, as assessed by groups of normal hearing listeners. Because atypical expressive prosody is associated with negative outcomes, clinicians should consider targeting prosody when working with individuals who use CIs.

Discrimination and sensorimotor adaptation of self-produced vowels in cochlear implant users

Humans rely on auditory feedback to monitor and adjust their speech for clarity. Cochlear implants (CIs) have helped over a million people restore access to auditory feedback, which significantly improves speech production. However, there is substantial variability in outcomes. This study investigates the extent to which CI users can use their auditory feedback to detect self-produced sensory errors and make adjustments to their speech, given the coarse spectral resolution provided by their implants. First, we used an auditory discrimination task to assess the sensitivity of CI users to small differences in formant frequencies of their self-produced vowels. Then, CI users produced words with altered auditory feedback in order to assess sensorimotor adaptation to auditory error. Almost half of the CI users tested can detect small, within-channel differences in their self-produced vowels, and they can utilize this auditory feedback towards speech adaptation. An acoustic hearing control group showed better sensitivity to the shifts in vowels, even in CI-simulated speech, and elicited more robust speech adaptation behavior than the CI users. Nevertheless, this study confirms that CI users can compensate for sensory errors in their speech and supports the idea that sensitivity to these errors may relate to variability in production.

Perceptions of Vocal Performance Impairment in Singers with and without Hearing Loss

INTRODUCTION

It is well understood that hearing plays an important role in accurate vocal production. Singers in particular rely on auditory cues and auditory feedback to reproduce specific pitch contours. Therefore, even mild hearing loss may have a detrimental effect on a singer's ability to perform. This study investigates the effect of hearing loss on self-reported vocal production in singers, specifically in the domains of pitch matching, pitch maintenance, vowel production, and dynamic control as well as the effect of hearing loss on vocal handicap.

METHODS

An 18-item electronic self-report survey was distributed to the members of the National Association of Teachers of Singing and to the Voice Foundation. Data collected included demographics, the Singing Voice Handicap Index-10 (SVHI-10), and a series of closed and open-ended questions. Demographic variables, variables related to the SVHI-10, and variables related to the newly introduced survey were included in a hierarchical regression analysis to determine significant relationships.

RESULTS

Among 206 eligible participants, 37 individuals reported a voice problem, 58 reported hearing loss, and 19 reported concurrent hearing loss and a voice problem. Among males, there were no significant differences between hearing impaired and normal hearing singers in reported pitch matching, pitch maintenance, dynamic control, and vowel matching when those with voice problems were excluded and included. However, in females, when singers with voice problems were excluded, there was a significant difference between hearing impaired and normal hearing singers in pitch matching (P = 0.38). Additionally, when singers with voice problems were included in the female subset, significant differences emerged between the hearing impaired and normal hearing singers in areas of pitch matching (P = 0.01) and vowel matching (P = 0.02). Further, controlling for gender, when excluding voice problems, there was a significant difference between the SVHI-10 scores of normal hearing (mean = 9.03) and hearing impaired participants (mean = 11.30, P = 0.02). This difference continued to be significant when including those with voice problems (normal hearing mean = 9.97, hearing impaired mean=14.1, P <0.0001). Additionally, individuals with hearing impairments were more likely to report higher perceived vocal handicap scores as reflected on the SVHI-10 than normal hearing respondents (P = 0.002). Other factors associated with higher likelihood of SVHI-10 score include older age (P = 0.008), having a voice problem (P <0.0001), and being paid to sing within the past six months (P = 0.001).

CONCLUSION

When controlling for voice problems, singers with hearing impairments subjectively did not perceive that they performed less accurately on pitch matching, pitch maintenance, dynamic control, and vowel matching, yet they scored higher on the SVHI-10 indicating vocal handicap. Further study is needed to characterize the relationship between perceived and measured vocal accuracy in singers with hearing loss.

The Impact of Bimodal Hearing on Speech Acoustics of Vowel Production in Adult Cochlear Implant Users

PURPOSE

This study aimed to investigate the acoustic changes in vowel production with different forms of auditory feedback via cochlear implant (CI), hearing aid (HA), and bimodal hearing (CI + HA).

METHOD

Ten post-lingually deaf adult bimodal CI users (aged 50-78 years) produced English vowels /i/, /ɛ/, /æ/, /ɑ/, /ʊ/, and /u/ in the context of /hVd/ during short-term use of no device (ND), HA, CI, and CI + HA. Segmental features (first formant frequency [F 1], second formant frequency [F 2], and vowel space area) and suprasegmental features (duration, intensity, and fundamental frequency [f o]) of vowel production were analyzed. Participants also categorized a vowel continuum synthesized from their own productions of /ɛ/ and /æ/ using HA, CI, and CI + HA.

RESULTS

F 1s of all vowels decreased; F 2s of front vowels but not back vowels increased; vowel space areas increased; and vowel durations, intensities, and f os decreased with statistical significance in the HA, CI, and CI + HA conditions relative to the ND condition. Only f os were lower, and vowel space areas were larger with CI and CI + HA than with HA. Average changes in f o, intensity, and F 1 from the ND condition to the HA, CI, and CI + HA conditions were positively correlated. Most participants did not show a typical psychometric function for vowel categorization, and thus, the relationship between vowel categorization and production was not tested.

CONCLUSIONS

The results suggest that acoustic, electric, and bimodal hearing have a measurable impact on vowel acoustics of post-lingually deaf adults when their hearing devices are turned on and off temporarily. Also, changes in f o and F 1 with the use of hearing devices may be largely driven by changes in intensity.

Effects of Cortical Stimulation on Feedback-Dependent Vocal Control in Non-Human Primates

OBJECTIVES

Hearing plays an important role in our ability to control voice, and perturbations in auditory feedback result in compensatory changes in vocal production. The auditory cortex (AC) has been proposed as an important mediator of this behavior, but causal evidence is lacking. We tested this in an animal model, hypothesizing that AC is necessary for vocal self-monitoring and feedback-dependent control, and that altering activity in AC during vocalization will interfere with vocal control.

METHODS

We implanted two marmoset monkeys (Callithrix jacchus) with bilateral AC electrode arrays. Acoustic signals were recorded from vocalizing marmosets while altering vocal feedback or electrically stimulating AC during random subsets of vocalizations. Feedback was altered by real-time frequency shifts and presented through headphones and electrical stimulation delivered to individual electrodes. We analyzed recordings to measure changes in vocal acoustics during shifted feedback and stimulation, and to determine their interaction. Results were correlated with the location and frequency tuning of stimulation sites.

RESULTS

Consistent with previous results, we found electrical stimulation alone evoked changes in vocal production. Results were stronger in the right hemisphere, but decreased with lower currents or repeated stimulation. Simultaneous stimulation and shifted feedback significantly altered vocal control for a subset of sites, decreasing feedback compensation at some and increasing it at others. Inhibited compensation was more likely at sites closer to vocal frequencies.

CONCLUSIONS

Results provide causal evidence that the AC is involved in feedback-dependent vocal control, and that it is sufficient and may also be necessary to drive changes in vocal production.

LEVEL OF EVIDENCE

N/A Laryngoscope, 133:1-10, 2023.

Speaking Rate, Immediate Memory, and Grammatical Processing in Prelingual Cochlear Implant Recipients

PURPOSE

This study examined the extent to which prelingual cochlear implant (CI) users show a slowed speaking rate compared with typical-hearing (TH) talkers when repeating various speech stimuli and whether the slowed speech of CI users relates to their immediate verbal memory.

METHOD

Participants included 10 prelingually deaf teenagers who received CIs before the age of 5 years and 10 age-matched TH teenagers. Participants repeated nonword syllable strings, word strings, and center-embedded sentences, with conditions balanced for syllable length and metrical structure. Participants' digit span forward and backward scores were collected to measure immediate verbal memory. Speaking rate data were analyzed using a mixed-design, repeated-measures analysis of variance, and the relationships between speaking rate and digit spans were evaluated by Pearson correlation.

RESULTS

Participants with CIs spoke more slowly than their TH peers during the sentence repetition task but not in the nonword string and word string repetition tasks. For the CI group, significant correlations emerged between speaking rate and digit span scores (both forward and backward) for the sentence repetition task but not for the nonword string or word string repetition task. For the TH group, no significant correlations were found.

CONCLUSIONS

The findings indicate a relation between slowed speech production, reduced immediate verbal memory, and diminished language capabilities of prelingual CI users, particularly for syntactic processing. These results support theories claiming that immediate memory, including components of a central executive, influences the speaking rate of these talkers. Implications for therapies designed to increase speech fluency in CI recipients are discussed.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21644795.

Adult Cochlear Implant Users Versus Typical Hearing Persons: An Automatic Analysis of Acoustic-Prosodic Parameters

PURPOSE

The aim of this study was to investigate the speech prosody of postlingually deaf cochlear implant (CI) users compared with control speakers without hearing or speech impairment.

METHOD

Speech recordings of 74 CI users (37 males and 37 females) and 72 age-balanced control speakers (36 males and 36 females) are considered. All participants are German native speakers and read Der Nordwind und die Sonne (The North Wind and the Sun), a standard text in pathological speech analysis and phonetic transcriptions. Automatic acoustic analysis is performed considering pitch, loudness, and duration features, including speech rate and rhythm.

RESULTS

In general, duration and rhythm features differ between CI users and control speakers. CI users read slower and have a lower voiced segment ratio compared with control speakers. A lower voiced ratio goes along with a prolongation of the voiced segments' duration in male and with a prolongation of pauses in female CI users. Rhythm features in CI users have higher variability in the duration of vowels and consonants than in control speakers. The use of bilateral CIs showed no advantages concerning speech prosody features in comparison to unilateral use of CI.

CONCLUSIONS

Even after cochlear implantation and rehabilitation, the speech of postlingually deaf adults deviates from the speech of control speakers, which might be due to changed auditory feedback. We suggest considering changes in temporal aspects of speech in future rehabilitation strategies.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21579171.

Cortical entrainment to speech produced by cochlear implant talkers and normal-hearing talkers

Cochlear implants (CIs) are commonly used to restore the ability to hear in those with severe or profound hearing loss. CIs provide the necessary auditory feedback for them to monitor and control speech production. However, the speech produced by CI users may not be fully restored to achieve similar perceived sound quality to that produced by normal-hearing talkers and this difference is easily noticeable in their daily conversation. In this study, we attempt to address this difference as perceived by normal-hearing listeners, when listening to continuous speech produced by CI talkers and normal-hearing talkers. We used a regenerative model to decode and reconstruct the speech envelope from the single-trial electroencephalogram (EEG) recorded on the scalp of the normal-hearing listeners. Bootstrap Spearman correlation between the actual speech envelope and the envelope reconstructed from the EEG was computed as a metric to quantify the difference in response to the speech produced by the two talker groups. The same listeners were asked to rate the perceived sound quality of the speech produced by the two talker groups as a behavioral sound quality assessment. The results show that both the perceived sound quality ratings and the computed metric, which can be seen as the degree of cortical entrainment to the actual speech envelope across the normal-hearing listeners, were higher in value for speech produced by normal hearing talkers than that for CI talkers. The first purpose of the study was to determine how well the envelope of speech is represented neurophysiologically via its similarity to the envelope reconstructed from EEG. The second purpose was to show how well this representation of speech for both CI and normal hearing talker groups differentiates in term of perceived sound quality.

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.

Cortical Entrainment to Speech Produced by Cochlear Implant Users and Normal-Hearing Talkers

The perceived sound quality of speech produced by hard-of-hearing individuals greatly depends on the degree and configuration of their hearing loss. A cochlear implant (CI) may provide some compensation and auditory feedback to monitor/control speech production. However, to date, the speech produced by CI users is still different in quality from that produced by normal-hearing (NH) talkers. In this study, we attempted to address this difference by examining the cortical activity of NH listeners when listening to continuous speech produced by 8 CI talkers and 8 NH talkers. We utilized a discriminative model to decode and reconstruct the speech envelope from the single-trial electroencephalogram (EEG) recorded from scalp electrode in NH listeners when listening to continuous speech. The correlation coefficient between the reconstructed envelope and original speech envelope was computed as a metric to quantify the difference in response to the speech produced by CI and NH talkers. The same listeners were asked to rate the perceived sound quality of the speech as a behavioral sound quality assessment. Both behavioral perceived sound quality ratings and the cortical entrainment to speech envelope were higher for the speech set produced by NH talkers than for the speech set produced by CI talkers.

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.

Early Cochlear Implantation Allows Deaf Children to Control Voice Pitch and Loudness independently

OBJECTIVE

Congenitally deaf children with a cochlear implant (CI) improve their speech production intelligibility, but their prosody, including stress and intonation produced by voice pitch and loudness changes, often differs from normal hearing people, which affects their fluent oral communication. This study is aimed to clarify abnormal characteristics of voice pitch and loudness control in CI recipients using a newly developed visually guided pitch change task.

METHODS

We included 13 normal hearing volunteers (NH group) and 17 congenitally deaf CI users who showed good speech intelligibility. The 17 CI users were divided into Early-CI and Late-CI groups, based on their age at implantation of 2.5 years. Using the visually guided pitch change task and acoustic voice analysis of sustained vowels, we assessed their vocal skills to maintain constant pitch and loudness and intentionally change the voice pitch independent from loudness. At the time of examination, the mean age was 24.1, 12.7, and 18.9 years in the NH, Early-CI, and Late-CI groups.

RESULTS

During constant vowel production, Early-CI and Late-CI groups showed more significant fluctuations in pitch and loudness than the NH group. However, when focusing on intentionally changing only the pitch of the voice, the Early-CI group was significantly better than the Late-CI group and comparable to the NH group in terms of their ability to change vocal pitch independently from loudness.

CONCLUSION

Among congenitally deaf patients, age at implantation was associated with the development of voice skills to control voice pitch and loudness separately, which may influence their fluent prosody production.

Effect of auditory feedback on speech intelligibility of adults with cochlear implants

PURPOSE

Auditory feedback (AF) contributes to speech intelligibility (SI) which is vital in social interactions to examine AF effect on SI of adults with cochlear implant (CI). The relationship between age of CI implantation and AF on SI was examined as well.

METHOD

Twenty native Hebrew speaker pre-lingual adults with a hearing loss using CIs from ages 2 to 19 years. Participants were recorded reading excerpts from a book and word lists from MIDBAR test in two situations-with and without using their CIs. Sixteen judges listened to the recordings and rated the speech characteristics of the participants reading the excerpts using an adapted version of Speech Intelligibility Test and Intelligibility Questionnaire for Teachers.

RESULTS

Significant differences were found between the SI of words of those who received CI before and after 3 years. AF effect was found only for the older implantation group. The questionnaire indicates good reliability among all the speech characteristics. The speech characteristics most affected by the AF are the disruption of consonants followed by the varied degrees of intonation precision and nasality.

CONCLUSIONS

AF affects speech characteristics differently and is vital to SI. The use of the adapted version of Speech Intelligibility Test and Intelligibility Questionnaire for Teachers can be used clinically to assess SI and rehabilitation of young adults with CI. AF accessed at a younger age decreases the dependency on AF in later years.

Post-lingual deaf adult cochlear implant users' speech and voice characteristics: cochlear implant turned-on versus turned-off

BACKGROUND

A time-period of turning off cochlear implant (CI) might affect the speech and voice features of the CI users due to loss of auditory feedback monitoring.

OBJECTIVES

To evaluate Persian-speaking CI users' speech and voice parameters in a device-on/off experiment.

MATERIAL AND METHODS

Forty-eight Persian-speaking adults with post-linguistic deafness who had received a unilateral CI and 50 normally-hearing counterparts were recruited. All CI users had to fulfill three phases of speech sampling, including the device-on, device-off (a 5-hourly period), and once again device-on phase. Their Fundamental frequency, Jitter, Shimmer, Harmonics-to-noise ratio, hyper-nasality score, and the percentage of speech intelligibility were assessed for both groups.

RESULTS

The findings revealed that the CI-on/off conditions significantly changed cochlear implanted participants' F0, Shimmer, HNR, and hyper-nasality values. However, no statistical differences were observed in Jitter and the percentage of speech intelligibility between the CI and control groups.

CONCLUSIONS

A short-term auditory deprivation in CI recipients could degrade the speech and voice quality in CI users, so that could change the quality of their speech resonance into hyper-nasality. However, when the CIs were turned on again, the quality of their speech and voice returned to normal-sounding.

Acoustically Induced Vocal Training for Individuals With Impaired Hearing

OBJECTIVES/HYPOTHESIS

Articulation, phonation, and resonance disorders in the speech of hearing-impaired-speakers reduces intelligibility. The study focusses on (1) whether nonacoustic feedback may facilitate the adjustment of the vocal tract, leading to increased vocal tract resonance, and (2) whether training with the feedback would be helpful for the subsequent formation of vowels.

STUDY DESIGN

Prospective.

METHODS

Seven profoundly hearing-impaired participants used acoustic sound waves in the frequency range of the first two vocal tract resonances applied in front of the open mouth at intensities above 1 Pa. They were asked to amplify the sound via adjusting the vocal tract. The sound waves corresponded to the first and second resonance frequencies of the vowels [u], [o], and [a]. The self-assessment of the participants and a software-based/auditory analysis was reported.

RESULTS

The participants were able to enhance the acoustic signal by adjusting the vocal tract shape. The self-perception of the participants, the auditory voice analysis, and the acoustic analysis of vowels were consistent with each other. While the maximum sound pressure levels were constant, the mean sound pressure levels increased. Breathiness and hoarseness declined during the exercises. Resonance/harmonic-to-noise ratio increased, especially for the vowels [u], [o], [a]. Furthermore, the positively connoted feedback from the participants indicated easier sound production.

CONCLUSION

Nonauditory feedback, based on acoustic waves, could be suitable for improving the formation of vowels. The findings are in accordance with a reduction of acoustic losses within the vocal tract.

Real-time feedback control of voice in cochlear implant recipients

OBJECTIVES

To evaluate feedback-dependent vocal control in cochlear implant patients using pitch-shifted auditory feedback.

METHODS

Twenty-three CI recipients with at least 6 months of implant experience were enrolled. Vocal recordings were performed while subjects repeated the vowel /e/ and vocal signals were altered in real-time using a digital effects processor to introduce a pitch-shift, presented back to subjects using headphones. Recordings were analyzed to determine pitch changes following the pitch-shifted feedback, and results compared to the magnitude of the shift as well as patient demographics.

RESULTS

Consistent with previous results, CI patients' voices had higher pitches with their implant turned off, a change explainable by increases in vocal loudness without the CI. CI patients rapidly compensated for pitch-shifted feedback by changing their vocal pitch, but only for larger shifts. Considerable inter-subject variability was present, and weakly correlated with the duration of implant experience and implant sound thresholds.

CONCLUSIONS

CI patients, like normal hearing individuals, are capable of real-time feedback-dependent control of their vocal pitch. However, CI patients are less sensitive to small feedback changes, possibly a result of courser CI frequency precision, and may explain poorer than normal vocal control in these patients.

LEVEL OF EVIDENCE

Level 3b.

Acoustic and Aerodynamic Analyses of the Voice of Prelingually Deaf Young Men After Cochlear Implantation

OBJECTIVE

The purpose of this study was to characterize the acoustic and aerodynamics of the voice of young men with prelingual deafness after cochlear implantation (CI) to provide a theoretical basis for their rehabilitation after CI.

METHODS

The CI group included 17 young men with prelingual deafness who implanted cochlear at 18-24 years old. The control group included 17 normally hearing young men at the same age. The 10-item Voice Handicap Index, acoustic parameters, and aerodynamic parameters were evaluated.

RESULTS

For the acoustic parameters, the F0, SDF0, and Jitter of the CI group were higher than those of the Control group, and these differences were statistically significant. Additionally, The difference in mean shimmer and mean NHR values between the CI group and the Control group was not statistically significant For the aerodynamic parameters, the subglottal pressure and aerodynamic power of the CI group were significantly higher than those of the Control group, whereas the MPT was significantly shorter.

DISCUSSION

Due to excessive stress on the laryngeal muscle and limited pneumo-phono-articulatory coordination, the young men in the CI group had a thin voice and poor voice control and muscle coordination, and they exhibited excessive laryngeal resistance. We propose that after CI, in addition to regular hearing and speech rehabilitation, voice training is also extremely important for prelingually deaf young men.

Surgical and therapeutic advances in the management of voice problems in children and young people

PURPOSE OF REVIEW

The current article reviews advances in both the assessment of paediatric voice disorders, as well as surgical, medical and therapeutic treatments.

RECENT FINDINGS

It is important to evaluate the impact of a voice disorder from both the parent and child perspective. Outpatient laryngoscopy with stroboscopy is very possible even in young children; however, high-speed ultrasound is a plausible alternative. High-speed videolaryngoscopy, videokymography and dynamic computed tomography, offer potential for augmenting the assessment of vocal fold vibratory characteristics in children. The evidence to support the efficacy of both indirect and direct voice therapy interventions is growing. The management of vocal fold palsy has advanced to include laryngeal reinnervation. Intubation injury with/without surgical intervention offers challenge and gives rise to voice disorders that may be lifelong.

SUMMARY

Although assessment and management practices of paediatric voice disorders closely follow those applied to adults, there are important differences and a developmental approach is required when considering both surgical and therapeutic management. Children can benefit from both indirect and direct therapy treatments following an ear, nose and throat assessment which utilizes paediatric instrumentation and considers the health of the entire airway. Underlying medical contributory factors should be explored and treated. Voice disorders due to congenital and acquired changes of the vocal tract may be amenable to surgery.