Stimulation Crosstalk Between Cochlear And Vestibular Spaces During Cochlear Electrical Stimulation

OBJECTIVES

Possible beneficial "crosstalk" during cochlear implant stimulation on otolith end organs has been hypothesized. The aim of this case-control study is to analyze the effect of electrical cochlear stimulation on the vestibule (otolith end-organ), when using a cochleo-vestibular implant, comparing vestibular stimulation (VI) and cochlear stimulation (CI).

METHODS

Four patients with bilateral vestibulopathy were included. A double electrode array research implant was implanted in all cases. Dynamic Gait Index (DGI), VOR gain measured by using vestibular head impulse test (vHIT), acoustic cervical myogenic responses (cVEMP) recordings, and electrical cVEMP were used in all cases. Trans-impedance Matrix (TIM) analysis was used to evaluate the current flow from the cochlea to the vestibule.

RESULTS

While patients did not have any clinical vestibular improvement with the CI stimulation alone, gait metrics of the patients revealed improvement when the vestibular electrode was stimulated. The average improvement in the DGI was 38% when the vestibular implant was activated, returning to the normal range in all cases. Our findings suggest that any current flow from the cochlear space to the otolith organs was insufficient for effective cross-stimulation. The functional results correlated with the data obtained in TIM analysis, confirming that there is no current flow from the cochlea to the vestibule.

CONCLUSION

The only way to produce effective electrical otolith end-organ stimulation, demonstrated with this research implant, is by direct electrical stimulation of the otolith end organs. No effective cross-stimulation was found from cochlear electrode stimulation.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:2349-2355, 2024.

Understanding Patient Utilization Patterns of Cochlear Implant Processors

OBJECTIVE

To evaluate the extent of benefit the second processor provides and to better understand utilization patterns regarding cochlear implant (CI) sound processors.

BACKGROUND

Institutional contracts determine the external CI sound processor hardware that a patient is eligible for. Despite the high prevalence of CI worldwide, there is a paucity in the literature regarding patient preferences and how patients utilize provided external hardware.

METHODS

A close-ended, multiple-choice survey was mailed to all patients over the age of 18 years who underwent CI between 2016 to 2020 at a tertiary academic medical center. Patients who received their CI hardware prior to 2018 were provided 2 processors, whereas those who received their hardware in 2018 or later were provided 1 processor.

RESULTS

A total of 100/263 surveys were returned for a response rate of 38.0%. Of the cohort with 1 processor, 31.3% experienced a period without a functioning processor and access to sound compared to 5.6% of the cohort with 2 processors (P = -.003). Of the cohort with 2 processors, 24.3% noted that they often or always utilize their second processor. When asked how important having a second processor was, 62.9% of the 2-processor group responded that it was very important (P = .001). The most common reason for utilizing the second processor was a damaged primary processor. Patients who received 2 processors had a significantly lower number of postoperative audiology clinic visits for device troubleshooting (P < .001).

CONCLUSION

Patients who have 2 CI external processors identify this as being very important to them and experience significantly less time without access to sound due to lack of a functioning processor. As institutional contracts often dictate whether a patient will receive 1 or 2 sound processors with their CI hardware, it is important to understand patient preferences and utilization patterns in order to guide patient-centric policies.

Auditory capacity of the better-hearing ear in asymmetric hearing loss

PURPOSE

Our aim was to investigate the course of the hearing capacity of the better-hearing ear in single-sided deafness (SSD) and asymmetric hearing loss (AHL) over time, in a multicenter study.

METHODS

We included 2086 pure-tone audiograms from 323 patients with SSD and AHL from four hospitals and 156 private practice otorhinolaryngologists. We collected: age, gender, etiology, duration of deafness, treatment with CI, number and monosyllabic speech recognition, numerical rating scale (NRS) of tinnitus intensity, and the tinnitus questionnaire according to Goebel and Hiller. We compared the pure tone audiogram of the better-hearing ear in patients with SSD with age- and gender-controlled hearing thresholds from ISO 7029:2017.

RESULTS

First, individuals with SSD showed a significantly higher hearing threshold from 0.125 to 8 kHz in the better-hearing ear compared to the ISO 7029:2017. The duration of deafness of the poorer-hearing ear showed no relationship with the hearing threshold of the better-hearing ear. The hearing threshold was significantly higher in typically bilaterally presenting etiologies (chronic otitis media, otosclerosis, and congenital hearing loss), except for Menière's disease. Second, subjects that developed AHL did so in 5.19 ± 5.91 years and showed significant reduction in monosyllabic word and number recognition.

CONCLUSIONS

Individuals with SSD show significantly poorer hearing in the better-hearing ear than individuals with NH from the ISO 7029:2017. In clinical practice, we should, therefore, inform our SSD patients that their disease is accompanied by a reduced hearing capacity on the contralateral side, especially in certain etiologies.

Audiovisual Processing Skills Before Cochlear Implantation Predict Postoperative Speech Recognition in Adults

OBJECTIVES

Adults with hearing loss (HL) demonstrate greater benefits of adding visual cues to auditory cues (i.e., "visual enhancement" [VE]) during recognition of speech presented in a combined audiovisual (AV) fashion when compared with normal-hearing peers. For patients with moderate-to-profound sensorineural HL who receive cochlear implants (CIs), it is unclear whether the restoration of audibility results in a decrease in the VE provided by visual cues during AV speech recognition. Moreover, it is unclear whether increased VE during the experience of HL before CI is beneficial or maladaptive to ultimate speech recognition abilities after implantation. It is conceivable that greater VE before implantation contributes to the enormous variability in speech recognition outcomes demonstrated among patients with CIs. This study took a longitudinal approach to test two hypotheses: (H1) Adult listeners with HL who receive CIs would demonstrate a decrease in VE after implantation; and (H2) The magnitude of pre-CI VE would predict post-CI auditory-only speech recognition abilities 6 months after implantation, with the direction of that relation supporting a beneficial, redundant, or maladaptive effect on outcomes.

DESIGN

Data were collected from 30 adults at two time points: immediately before CI surgery and 6 months after device activation. Pre-CI speech recognition performance was measured in auditory-only (A-only), visual-only, and combined AV fashion for City University of New York (CUNY) sentences. Scores of VE during AV sentence recognition were computed. At 6 months after CI activation, participants were again tested on CUNY sentence recognition in the same conditions as pre-CI. H1 was tested by comparing post- versus pre-CI VE scores. At 6 months of CI use, additional open-set speech recognition measures were also obtained in the A-only condition, including isolated words, words in meaningful AzBio sentences, and words in AzBio sentences in multitalker babble. To test H2, correlation analyses were performed to assess the relation between post-CI A-only speech recognition scores and pre-CI VE scores.

RESULTS

Inconsistent with H1, after CI, participants did not demonstrate a significant decrease in VE scores. Consistent with H2, preoperative VE scores positively predicted postoperative scores of A-only sentence recognition for both sentences in quiet and in babble (rho = 0.40 to 0.45, p < 0.05), supporting a beneficial effect of pre-CI VE on post-CI auditory outcomes. Pre-CI VE was not significantly related to post-CI isolated word recognition. The raw pre-CI CUNY AV scores also predicted post-CI A-only speech recognition scores to a similar degree as VE scores.

CONCLUSIONS

After implantation, CI users do not demonstrate a decrease in VE from before surgery. The degree of VE during AV speech recognition before CI positively predicts A-only sentence recognition outcomes after implantation, suggesting the potential value of AV testing of CI patients preoperatively to help predict and set expectations for postoperative outcomes.

Auditory, Visual, and Cognitive Abilities in Normal-Hearing Adults, Hearing Aid Users, and Cochlear Implant Users

OBJECTIVES

Speech understanding is considered a bimodal and bidirectional process, whereby visual information (i.e., speechreading) and also cognitive functions (i.e., top-down processes) are involved. Therefore, the purpose of the present study is twofold: (1) to investigate the auditory (A), visual (V), and cognitive (C) abilities in normal-hearing individuals, hearing aid (HA) users, and cochlear implant (CI) users, and (2) to determine an auditory, visual, cognitive (AVC)-profile providing a comprehensive overview of a person's speech processing abilities, containing a broader variety of factors involved in speech understanding.

DESIGN

Three matched groups of subjects participated in this study: (1) 31 normal-hearing adults (mean age = 58.76), (2) 31 adults with moderate to severe hearing loss using HAs (mean age = 59.31), (3) 31 adults with a severe to profound hearing loss using a CI (mean age = 58.86). The audiological assessments consisted of pure-tone audiometry, speech audiometry in quiet and in noise. For evaluation of the (audio-) visual speech processing abilities, the Test for (Audio) Visual Speech perception was used. The cognitive test battery consisted of the letter-number sequencing task, the letter detection test, and an auditory Stroop test, measuring working memory and processing speed, selective attention, and cognitive flexibility and inhibition, respectively. Differences between the three groups were examined using a one-way analysis of variance or Kruskal-Wallis test, depending on the normality of the variables. Furthermore, a principal component analysis was conducted to determine the AVC-profile.

RESULTS

Normal-hearing individuals scored better for both auditory, and cognitive abilities compared to HA users and CI users, listening in a best aided condition. No significant differences were found for speech understanding in a visual condition, despite a larger audiovisual gain for the HA users and CI users. Furthermore, an AVC-profile was composed based on the different auditory, visual, and cognitive assessments. On the basis of that profile, it is possible to determine one comprehensive score for auditory, visual, and cognitive functioning. In the future, these scores could be used in auditory rehabilitation to determine specific strengths and weaknesses per individual patient for the different abilities related to the process of speech understanding in daily life.

CONCLUSIONS

It is suggested to evaluate individuals with hearing loss from a broader perspective, considering more than only the typical auditory abilities. Also, cognitive and visual abilities are important to take into account to have a more complete overview of the speech understanding abilities in daily life.

Computed tomography multi-planar and 3D image assessment protocol for detailed analysis of inner ear malformations in patients undergoing cochlear implantation counseling

<b><br>Introduction:</b> Congenital inner ear malformations resulting from embryogenesis may be visualized in radiological scans. Many attempts have been made to describe and classify the defects of the inner ear based on anatomical and radiological findings.</br> <b><br>Aim:</b> The aim was to propose and discuss computed tomography multi-planar and 3D image assessment protocols for detailed analysis of inner ear malformations in patients undergoing cochlear implantation counseling.</br> <b><br>Material and methods:</b> A retrospective analysis of 22 malformed inner ears. CT scans were analyzed using the Multi-Planar Reconstruction (MPR) option and 3D reconstruction.</br> <b><br>Results:</b> The protocol of image interpretation was developed to allow reproducibility for evaluating each set of images. The following malformations were identified: common cavity, cochlear hypoplasia type II, III, and IV, incomplete partition type II and III, and various combinations of vestibule labyrinth malformations. All anomalies have been presented and highlighted in figures with appropriate descriptions for easier identification. Figures of normal inner ears were also included for comparison. 3D reconstructions for each malformation were presented, adding clinical value to the detailed analysis.</br> <b><br>Conclusions:</b> Properly analyzing CT scans in cochlear implantation counseling is a necessary and beneficial tool for appropriate candidate selection and preparation for surgery. As proposed in this study, the unified scans evaluation scheme simplifies the identification of malformations and reduces the risk of omitting particular anomalies. Multi-planar assessment of scans provides most of the necessary details. The 3D reconstruction technique is valuable in addition to diagnostics influencing the decision-making process. It can minimize the risk of misdiagnosis. Disclosure of the inner ear defect and its precise imaging provides detailed anatomical knowledge of each ear, enabling the selection of the appropriate cochlear implant electrode and the optimal surgical technique.</br>.

Adaptation of the Cochlear Implant Quality of Life-35 Profile Into German

PURPOSE

The adaptation of existing questionnaires is a valuable method to make instruments available in multiple languages. It is necessary to assure the quality of an adaptation by following adaptation guidelines. The Cochlear Implant Quality of Life-35 Profile (CIQOL-35 Profile) was developed and validated to measure the functional abilities in English-speaking adult CI users but is not yet available in German. In this study, we performed a cross-cultural adaptation of this instrument to make it applicable in research and rehabilitation with German-speaking patients.

METHOD

This study followed established practice guidelines for translating and adapting hearing-related questionnaires. Professional translators and health care professionals with experience with patients with hearing loss translated all items forward and backward multiple times. A committee reviewed the process and decided when a satisfactory consensus was achieved. Next, we examined the intelligibility of the German version using cognitive interviews with 15 adult CI users.

RESULTS

For most items, there was no difficulty with direct translation. In items that turned out to be more difficult to translate, it proved to be very helpful to compare the back translation to the original version, discuss the wording in the committee, and ask the source-language questionnaire developer. During the interviews, issues of comprehension for some phrases were identified. These phrases were changed according to the participant's questions and suggestions.

CONCLUSIONS

The CIQOL-35 Profile was successfully adapted into German. The German version of the questionnaire is now available for research and clinical practice. Further validation of the German CIQOL-35 Profile is in progress.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25386571.

Psychoacoustic and electroencephalographic responses to changes in amplitude modulation depth and frequency in relation to speech recognition in cochlear implantees

Temporal envelope modulations (TEMs) are one of the most important features that cochlear implant (CI) users rely on to understand speech. Electroencephalographic assessment of TEM encoding could help clinicians to predict speech recognition more objectively, even in patients unable to provide active feedback. The acoustic change complex (ACC) and the auditory steady-state response (ASSR) evoked by low-frequency amplitude-modulated pulse trains can be used to assess TEM encoding with electrical stimulation of individual CI electrodes. In this study, we focused on amplitude modulation detection (AMD) and amplitude modulation frequency discrimination (AMFD) with stimulation of a basal versus an apical electrode. In twelve adult CI users, we (a) assessed behavioral AMFD thresholds and (b) recorded cortical auditory evoked potentials (CAEPs), AMD-ACC, AMFD-ACC, and ASSR in a combined 3-stimulus paradigm. We found that the electrophysiological responses were significantly higher for apical than for basal stimulation. Peak amplitudes of AMFD-ACC were small and (therefore) did not correlate with speech-in-noise recognition. We found significant correlations between speech-in-noise recognition and (a) behavioral AMFD thresholds and (b) AMD-ACC peak amplitudes. AMD and AMFD hold potential to develop a clinically applicable tool for assessing TEM encoding to predict speech recognition in CI users.

Investigating Perception to Production Transfer in Children With Cochlear Implants: A High Variability Phonetic Training Study

PURPOSE

This study builds upon an established effective training method to investigate the advantages of high variability phonetic identification training for enhancing lexical tone perception and production in Mandarin-speaking pediatric cochlear implant (CI) recipients, who typically face ongoing challenges in these areas.

METHOD

Thirty-two Mandarin-speaking children with CIs were quasirandomly assigned into the training group (TG) and the control group (CG). The 16 TG participants received five sessions of high variability phonetic training (HVPT) within a period of 3 weeks. The CG participants did not receive the training. Perception and production of Mandarin tones were administered before (pretest) and immediately after (posttest) the completion of HVPT via lexical tone recognition task and picture naming task. Both groups participated in the identical pretest and posttest with the same time frame between the two test sessions.

RESULTS

TG showed significant improvement from pretest to posttest in identifying Mandarin tones for both trained and untrained speech stimuli. Moreover, perceptual learning of HVPT significantly facilitated trainees' production of T1 and T2 as rated by a cohort of 10 Mandarin-speaking adults with normal hearing, which was corroborated by acoustic analyses revealing improved fundamental frequency (F0) median for T1 and T2 production and enlarged F0 movement for T2 production. In contrast, TG children's production of T3 and T4 showed nonsignificant changes across two test sessions. Meanwhile, CG did not exhibit significant changes in either perception or production.

CONCLUSIONS

The results suggest a limited and inconsistent transfer of perceptual learning to lexical tone production in children with CIs, which challenges the notion of a robust transfer and highlights the complexity of the interaction between perceptual training and production outcomes. Further research on individual differences with a longitudinal design is needed to optimize the training protocol or tailor interventions to better meet the diverse needs of learners.

Speech Sound Categories Affect Lexical Competition: Implications for Analytic Auditory Training

OBJECTIVES

We provide a novel application of psycholinguistic theories and methods to the field of auditory training to provide preliminary data regarding which minimal pair contrasts are more difficult for listeners with typical hearing to distinguish in real-time.

DESIGN

Using eye-tracking, participants heard a word and selected the corresponding image from a display of four: the target word, two unrelated words, and a word from one of four contrast categories (i.e., voiced-initial [e.g., peach-beach], voiced-final [e.g., back-bag], manner-initial [e.g., talk-sock], and manner-final [e.g., bat-bass]).

RESULTS

Fixations were monitored to measure how strongly words compete for recognition depending on the contrast type (voicing, manner) and location (word-initial or final). Manner contrasts competed more for recognition than did voicing contrasts, and contrasts that occurred in word-final position were harder to distinguish than word-initial position.

CONCLUSION

These results are an important initial step toward creating an evidence-based hierarchy for auditory training for individuals who use cochlear implants.

[Influence of overtones and undertones on melody recognition with a cochlear implant with SSD]

Many cochlear implant (CI) users have difficulties recognising pitches and melodies because pitch transmission is blurred and shifted. This study investigates whether postlingually deafened adult CI users recognize melodies better when overtones are removed or undertones are added.Fifteen unilaterally postlingually deafened CI users (single sided deafness = SSD) were included aged 22 to 73 years (MW 52, SD 11.6) with CI hearing experience between 3 and 75 months (MW 33, SD 21.0) with varying MED-EL devices. Three short piano melodies were presented to them firstly to the normal-hearing ear and then in modified overtone or undertone variants and the original variant to the CI ear. These variants should be identified as one of the three original melodies. In addition, musical experience and ability were assessed by the Munich Music Questionnaire and the MiniPROMS music tests.The CI users showed the best melody recognition in the fundamental frequency variant. The overtone variant with the third overtone was as good as the original variant with all overtones with regard to melody recognition (p=1). However, the undertone variant with the first undertone was recognised significantly worse than the fundamental version (p=0.032). Furthermore, there was no correlation between musical experience or musical ability and the number of melodies recognised (p>0.1).Since a reduction of overtones did not worsen the melody recognition, overtone reduction should be considered in future music processing programs for the CI. This could reduce the energy consumption of the CI.

Importance of age at 2nd implantation and interimplant interval to the outcome of bilateral prelingually deafened pediatric cochlear implantation

BACKGROUND

In Taiwan, the number of cases of sequential bilateral pediatric cochlear implantation (CI) is increasing but data regarding its effectiveness and impact of the reimbursement policy are lacking. We examined the speech perception and quality of life (QOL) of bilateral prelingually deaf children who underwent sequential CI, considering the effects of age at the time of second implantation and interimplant interval.

METHODS

We enrolled 124 Mandarin-speaking participants who underwent initial cochlear implant (CI1) in 2001-2019 and a second CI (CI2) in 2015-2020. Patients were followed up for ≥2 years and were categorized into groups based on age at the time of CI2 implantation (<3.5, 3.6-7, 7.1-10, 10.1-13, and 13.1-18 years) and interimplant interval (0.5-3, 3.1-5, 5.1-7, 7.1-10, and >10 years). We evaluated speech perception, device usage rates, and QOL using subjective questionnaires (Speech, Spatial, and Qualities of Hearing and Comprehension Cochlear Implant Questionnaire).

RESULTS

Speech perception scores of CI2 were negatively correlated with ages at the time of CI1 and CI2 implantation and interimplant interval. Older age and a longer interimplant interval were associated with higher nonuse rates for CI2 and worse auditory performance and QOL. Among individuals aged >13 years with interimplant intervals >10 years, up to 44% did not use their second ear. Patients aged 7.1 to 10 years had better speech perception and higher questionnaire scores than those aged 10.1 to 13 and 13.1 to 18 years. Furthermore, patients aged 10.1 to 13 years had a lower rate of continuous CI2 usage compared to those aged 7.1 to 10 years.

CONCLUSION

Timely implantation of CI2 is essential to achieve optimal outcomes, particularly among sequentially implanted patients with long-term deafness in the second ear and no improvement with hearing aids following CI1 implantation. For CI2 implantation, an upper limit of age of 10 years and interimplant interval of 7 years are essential to prevent suboptimal outcomes. These data can provide useful information to implant recipients, their families, and medical and audiological professionals, enabling a comprehensive understanding of the benefits and potential impacts of the timing of CI2 implantation.

Improved Postoperative Speech Recognition and Processor Use With Early Cochlear Implant Activation

OBJECTIVE

To report speech recognition outcomes and processor use based on timing of cochlear implant (CI) activation.

STUDY DESIGN

Retrospective cohort.

SETTING

Tertiary referral center.

PATIENTS

A total of 604 adult CI recipients from October 2011 to March 2022, stratified by timing of CI activation (group 1: ≤10 d, n = 47; group 2: >10 d, n = 557).

MAIN OUTCOME MEASURES

Average daily processor use; Consonant-Nucleus-Consonant (CNC) and Arizona Biomedical (AzBio) in quiet at 1-, 3-, 6-, and 12-month visits; time to peak performance.

RESULTS

The groups did not differ in sex ( p = 0.887), age at CI ( p = 0.109), preoperative CNC ( p = 0.070), or preoperative AzBio in quiet ( p = 0.113). Group 1 had higher median daily processor use than group 2 at the 1-month visit (12.3 versus 10.7 h/d, p = 0.017), with no significant differences at 3, 6, and 12 months. The early activation group had superior median CNC performance at 3 months (56% versus 46%, p = 0.007) and 12 months (60% versus 52%, p = 0.044). Similarly, the early activation group had superior median AzBio in quiet performance at 3 months (72% versus 59%, p = 0.008) and 12 months (75% versus 68%, p = 0.049). Both groups were equivalent in time to peak performance for CNC and AzBio. Earlier CI activation was significantly correlated with higher average daily processor use at all follow-up intervals.

CONCLUSION

CI activation within 10 days of surgery is associated with increased early device usage and superior speech recognition at both early and late follow-up visits. Timing of activation and device usage are modifiable factors that can help optimize postoperative outcomes in the CI population.

Socioeconomic and ethnic disparities associated with access to cochlear implantation for severe-to-profound hearing loss: A multicentre observational study of UK adults

BACKGROUND

Patients with severe-to-profound hearing loss may benefit from management with cochlear implants. These patients need a referral to a cochlear implant team for further assessment and possible surgery. The referral pathway may result in varied access to hearing healthcare. This study aimed to explore referral patterns and whether there were any socioeconomic or ethnic associations with the likelihood of referral. The primary outcome was to determine factors influencing referral for implant assessment. The secondary outcome was to identify factors impacting whether healthcare professionals had discussed the option of referral.

METHODS AND FINDINGS

A multicentre multidisciplinary observational study was conducted in secondary care Otolaryngology and Audiology units in Great Britain. Adults fulfilling NICE (2019) audiometric criteria for implant assessment were identified over a 6-month period between 1 July and 31 December 2021. Patient- and site-specific characteristics were extracted. Multivariable binary logistic regression was employed to compare a range of factors influencing the likelihood of implant discussion and referral including patient-specific (demographics, past medical history, and degree of hearing loss) and site-specific factors (cochlear implant champion and whether the hospital performed implants). Hospitals across all 4 devolved nations of the UK were invited to participate, with data submitted from 36 urban hospitals across England, Scotland, and Wales. Nine hospitals (25%) conducted cochlear implant assessments. The majority of patients lived in England (n = 5,587, 86.2%); the rest lived in Wales (n = 419, 6.5%) and Scotland (n = 233, 3.6%). The mean patient age was 72 ± 19 years (mean ± standard deviation); 54% were male, and 75·3% of participants were white, 6·3% were Asian, 1·5% were black, 0·05% were mixed, and 4·6% were self-defined as a different ethnicity. Of 6,482 submitted patients meeting pure tone audiometric thresholds for cochlear implantation, 311 already had a cochlear implant. Of the remaining 6,171, 35.7% were informed they were eligible for an implant, but only 9.7% were referred for assessment. When adjusted for site- and patient-specific factors, stand-out findings included that adults were less likely to be referred if they lived in more deprived area decile within Indices of Multiple Deprivation (4th (odds ratio (OR): 2·19; 95% confidence interval (CI): [1·31, 3·66]; p = 0·002), 5th (2·02; [1·21, 3·38]; p = 0·05), 6th (2·32; [1·41, 3·83]; p = 0.05), and 8th (2·07; [1·25, 3·42]; p = 0·004)), lived in London (0·40; [0·29, 0·57]; p < 0·001), were male (females 1·52; [1·27, 1·81]; p < 0·001), or were older (0·97; [0·96, 0·97]; p < 0·001). They were less likely to be informed of their potential eligibility if they lived in more deprived areas (4th (1·99; [1·49, 2·66]; p < 0·001), 5th (1·75; [1·31, 2·33], p < 0·001), 6th (1·85; [1·39, 2·45]; p < 0·001), 7th (1·66; [1·25, 2·21]; p < 0·001), and 8th (1·74; [1·31, 2·31]; p < 0·001) deciles), the North of England or London (North 0·74; [0·62, 0·89]; p = 0·001; London 0·44; [0·35, 0·56]; p < 0·001), were of Asian or black ethnic backgrounds compared to white patients (Asian 0·58; [0·43, 0·79]; p < 0·001; black 0·56; [0·34, 0·92]; p = 0·021), were male (females 1·46; [1·31, 1·62]; p < 0·001), or were older (0·98; [0·98, 0·98]; p < 0·001). The study methodology was limited by its observational nature, reliance on accurate documentation of the referring service, and potential underrepresentation of certain demographic groups.

CONCLUSIONS

The majority of adults meeting pure tone audiometric threshold criteria for cochlear implantation are currently not appropriately referred for assessment. There is scope to target underrepresented patient groups to improve referral rates. Future research should engage stakeholders to explore the reasons behind the disparities. Implementing straightforward measures, such as educational initiatives and automated pop-up tools for immediate identification, can help streamline the referral process.

Long term effects of cochlear implant surgery on vestibular system in pediatric population

OBJECTIVE

The aim was to evaluate the vestibular system of children who had undergone cochlear implant surgery and to compare them with the healthy population by vestibulo-ocular reflex (VOR) gains in unilateral and bilateral implant users, with the implants both on and off.

METHODS

Patients older than 5 years who had undergone cochlear implant surgery between 2012 and 2020 and who were cochlear implant users for at least one year were included. After consent was obtained, a video head impulse test (VHIT) was performed to evaluate the three semicircular canals, with devices on and off, and VOR gains were evaluated. VHIT was also used to assess VOR gains in the control group. The VOR gains of the study and control groups, VOR gains of unilateral and bilateral implant users, and VOR gains with implants on and off were compared.

RESULTS

When the VOR gains of 24 unilateral and 13 bilateral cochlear implant users and the control group (n = 30) were compared, a significant difference was found only in the anterior semicircular canal, although the VOR gains were found to be low in all three semicircular canals in the implant users (p < 0.05). There was no significant difference between the VOR gains of unilateral and bilateral implant users. There was no significant difference between the VOR gains when either on or off. There was no correlation between cochlear implant usage time, implant insertion age, patient age and VOR gain.

CONCLUSION

The effects of cochlear implant surgery on the vestibular system continue in the late period, but no correlation was observed between implant usage time and VOR gain after the first year. It was observed that having the cochlear implant on or off had no effect on VOR gain. Furthermore, bilateral implant surgery did not lead to additional vestibular dysfunction compared to unilateral implant surgery.

Efficacy of vestibular rehabilitation program in children with balance disorders and sensorineural hearing loss

OBJECTIVE

Asses the efficacy of a Vestibular-balance rehabilitation program to minimize or reverse balance disability in children with sensorineural hearing loss.

METHOD

Forty-five hearing-impaired children with balance deficits (i.e., variable degrees of sensorineural hearing loss or auditory neuropathy). Thirty-five were rehabilitated with cochlear implants, and ten with hearing aids. Their age ranged from 4 to 10 years old. A Pre-rehab evaluation was done using questionnaires, neuromuscular evaluation, vestibular and balance office testing, and vestibular lab testing (using cVEMP and caloric test). Customized balances, as well as vestibular rehabilitation exercises, have been applied for three months. That was followed by post-rehab assessment, including the Arabic DHI questionnaire, PBS, BESS, HTT, and DVA test.

RESULTS

There was a statistically significant difference in all measured parameters (including the Arabic DHI questionnaire, PBS, BESS, HTT, and DVA test) after rehabilitation.

CONCLUSIONS

Vestibular-balance rehabilitation intervention positively impacts vestibular and balance functions in hearing-impaired children.

Temporal pitch matching with bilateral cochlear implants

Interaural pitch matching is a common task used with bilateral cochlear implant (CI) users, although studies measuring this have largely focused on place-based pitch matches. Temporal-based pitch also plays an important role in CI users' perception, but interaural temporal-based pitch matching has not been well characterized for CI users. To investigate this, bilateral CI users were asked to match amplitude modulation frequencies of stimulation across ears. Comparisons were made to previous place-based pitch matching data that were collected using similar procedures. The results indicate that temporal-based pitch matching is particularly sensitive to the choice of reference ear.

Evaluation of language, attention, and memory skills in children with auditory brainstem implants

PURPOSE

This study aimed to evaluate attention, memory, and language skills in children with auditory brainstem implants and cochlear implants.

METHODS

This study included 20 children with auditory brainstem implants (ABI) and 20 cochlear implanted (CI) children between the ages of 6 years and 8 years 11 months and their families. "Test of Language Development: Primary (TOLD-P:4)" was used to assess language skills, "STROOP Test, Visual-Aural Digit Span (VADS) test, and Cancellation Test" were used to evaluate attention and memory skills. In addition, the functional outcomes of hearing skills in daily life were scored by "Auditory Behavior in Everyday Life (ABEL) scale". The significance level was determined as 0.05.

RESULTS

Children with ABI showed lower language skills than children with CI in terms of TOLD-P:4 language test scores, STROOP sub-test completion times, and the VADS and Cancellation test scores (p < 0.05). In addition, statistically significant correlations were found between language, attention, memory skills, and auditory behavior scale.

CONCLUSIONS

This study is one of the limited numbers of studies investigating cognitive processes in children with ABI. Since attention and memory are correlated with language skills, it is recommended that the development of cognition should be considered in follow-up and intervention approaches of children with ABI and/or CI.

Relationships between bilateral auditory brainstem activity and inter-implant interval in children with cochlear implants

PURPOSE

To investigate the effect of the interval between bilateral cochlear implantation on the development of bilateral peripheral auditory pathways as revealed by the electrically evoked auditory brainstem response (EABR).

METHODS

Fifty-eight children with profound bilateral sensorineural hearing loss were recruited. Among them, 33 children received sequential bilateral cochlear implants (CIs), and 25 children received simultaneous bilateral CIs. The bilateral EABRs evoked by electrical stimulation from the CI electrode were recorded on the day of second-side CI activation.

RESULTS

The latencies of wave III (eIII) and wave V (eV) were significantly shorter on the first CI side than on the second CI side in children with sequential bilateral CIs but were similar between the two sides in children with simultaneous bilateral CIs. Furthermore, the latencies were prolonged from apical to basal channels along the cochlea in the two groups. In children with sequential CIs, the inter-implant interval was negatively correlated with the eV latency on the first CI side and was positively correlated with bilateral differences in the eIII and eV latencies.

CONCLUSIONS

Unilateral CI use promotes the maturation of ipsilateral auditory conduction function. However, a longer inter-implant interval results in more unbalanced development of bilateral auditory brainstem pathways. Bilateral cochlear implantation with no or a short interval is recommended.

How to vocode: Using channel vocoders for cochlear-implant research

The channel vocoder has become a useful tool to understand the impact of specific forms of auditory degradation-particularly the spectral and temporal degradation that reflect cochlear-implant processing. Vocoders have many parameters that allow researchers to answer questions about cochlear-implant processing in ways that overcome some logistical complications of controlling for factors in individual cochlear implant users. However, there is such a large variety in the implementation of vocoders that the term "vocoder" is not specific enough to describe the signal processing used in these experiments. Misunderstanding vocoder parameters can result in experimental confounds or unexpected stimulus distortions. This paper highlights the signal processing parameters that should be specified when describing vocoder construction. The paper also provides guidance on how to determine vocoder parameters within perception experiments, given the experimenter's goals and research questions, to avoid common signal processing mistakes. Throughout, we will assume that experimenters are interested in vocoders with the specific goal of better understanding cochlear implants.

Evaluating Listening Effort in Unilateral, Bimodal, and Bilateral Cochlear Implant Users

OBJECTIVE

Evaluate listening effort (LE) in unilateral, bilateral, and bimodal cochlear implant (CI) users. Establish an easy-to-implement task of LE that could be useful for clinical decision making.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary neurotology center.

METHODS

The Sentence Final Word Identification and Recall Task, an established measure of LE, was modified to include challenging listening conditions (multitalker babble, gender, and emotional variation; test), in addition to single-talker sentences (control). Participants listened to lists of sentences in each condition and recalled the last word of each sentence. LE was quantified by percentage of words correctly recalled and was compared across conditions, across CI groups, and within subjects (best aided vs monaural).

RESULTS

A total of 24 adults between the ages of 37 and 82 years enrolled, including 4 unilateral CI users (CI), 10 bilateral CI users (CICI), and 10 bimodal CI users (CIHA). Task condition impacted LE (P < .001), but hearing configuration and listener group did not (P = .90). Working memory capacity and contralateral hearing contributed to individual performance.

CONCLUSION

This study adds to the growing body of literature on LE in challenging listening conditions for CI users and demonstrates feasibility of a simple behavioral task that could be implemented clinically to assess LE. This study also highlights the potential benefits of bimodal hearing and individual hearing and cognitive factors in understanding individual differences in performance, which will be evaluated through further research.

Use of Diagnostic Audiology and Cochlear Implantation in the US

This study examined if cochlear implant (CI) use varies geographically within the US and if diagnostic audiology use correlates with CI usage.

World of sounds (Seslerin Dünyası): A mobile auditory training game for children with cochlear implants

OBJECTIVES

The aim of this study is to develop a mobile auditory training application based on gaming for children aged 3-5 years using cochlear implants and to evaluate its usability.

METHODS

4 games were developed in the scope of the application World of Sounds; the crucible sound for auditory awareness, mole hunting for auditory discrimination, find the sound for auditory recognition, and choo-choo for auditory comprehension. The prototype was applied to 20 children with normal hearing and 20 children with cochlear implants, all of whom were aged 3-5. The participants were asked to fill out the Game Evaluation Form for Children. Moreover, 40 parents were included in the study, and the Evaluation Form for the Application was applied.

RESULTS

According to the form, at least 80% of children using cochlear implants, and all children in the healthy group, responded well to the usability factors. All factors were obtained as highly useable by parents of the children using cochlear implants. The results indicated that in the healthy group, the usefulness and motivation factors were above moderate, and the other factors were highly useable. In the mole-hunting game, there was no significant difference between the groups in the easy level of the first sub-section (p > 0.05). There was a significant difference between the groups in terms of the other sub-sections of the mole-hunting game and all sub-sections of the crucible sound, find the sound, and the choo-choo games (p < 0.05). While there was no correlation between duration of cochlear implant use and ADSI scores and the third sub-section of the crucible sound game (p > 0.05); a correlation was found in the other sub-sections of crucible sound and all sub-sections of the mole hunting, find the sound, and Choo-Choo games (p < 0.05).

CONCLUSION

It is thought that the application World of Sounds can serve as an accessible option to support traditional auditory rehabilitation for children with cochlear implants.

The challenge of a mature final diagnosis of hearing loss severity and early cochlear implantation

PURPOSE

Despite the recent trend of cochlear implantation (CI) at the age of six or even four months is prevalent in many centers around the world, clinicians should be cautious because perinatal risk factors of auditory neuropathy and/or delayed maturation carry the possibility of reversible hearing loss, yielding better auditory performance at the age of one year. The purpose of this study is to raise awareness that early CI may not be universal for all patients. In addition, we specify the factors to be considered in the pre-operative evaluation of CI in infants younger than one year.

METHODS AND RESULTS

This study describes four cases provisionally diagnosed with severe to profound sensorineural hearing loss that were presented to the CI clinic to determine candidacy for implantation. Two cases had histories of prematurity, one had Down syndrome, and one had a family history of hearing loss. None of the study cases were candidates for CI, as they had varying degrees of hearing improvement.

CONCLUSION

Although early CI may yield better auditory performance, the final diagnosis should be made only after repeated subjective and objective measurements as well as family feedback on the child's auditory performance, especially in preterm children. Early auditory brainstem response (ABR) prior to the age of one year in children with cognitive, neurologic, or developmental comorbidities should be interpreted with caution, as ABR "alone" could not accurately represent the child's true hearing ability in this patient population.

Variables Affecting Cochlear Implant Performance After Loss of Residual Hearing

OBJECTIVE

Determine variables that influence post-activation performance for cochlear implant (CI) recipients who lost low-frequency acoustic hearing.

METHODS

A retrospective review evaluated CNC word recognition for adults with normal to moderately severe low-frequency hearing (preoperative unaided thresholds of ≤70 dB HL at 250 Hz) who were implanted between 2012 and 2021 at a tertiary academic center, lost functional acoustic hearing, and were fit with a CI-alone device. Performance scores were queried from the 1, 3, 6, 12, and 24-month post-activation visits. A linear mixed model evaluated the effects of age at implantation, array length (long vs. mid/short), and preoperative low-frequency hearing (normal to mild, moderate, and moderately severe) on speech recognition with a CI alone.

RESULTS

113 patients met the inclusion criteria. There was a significant main effect of interval (p < 0.001), indicating improved word recognition post-activation despite loss of residual hearing. There were significant main effects of age (p = 0.029) and array length (p = 0.038), with no effect of preoperative low-frequency hearing (p = 0.171). There was a significant 2-way interaction between age and array length (p = 0.018), indicating that older adults with mid/short arrays performed more poorly than younger adults with long lateral wall arrays when functional acoustic hearing was lost.

CONCLUSION

CI recipients with preoperative functional low-frequency hearing experience a significant improvement in speech recognition with a CI alone as compared to preoperative performance-despite the loss of low-frequency hearing. Age and electrode array length may play a role in post-activation performance. These data have implications for the preoperative counseling and device selection for hearing preservation candidates.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1868-1873, 2024.

Exploring the Use of Interleaved Stimuli to Measure Cochlear-Implant Excitation Patterns

PURPOSE

Attempts to use current-focussing strategies with cochlear implants (CI) to reduce neural spread-of-excitation have met with only mixed success in human studies, in contrast to promising results in animal studies. Although this discrepancy could stem from between-species anatomical and aetiological differences, the masking experiments used in human studies may be insufficiently sensitive to differences in excitation-pattern width.

METHODS

We used an interleaved-masking method to measure psychophysical excitation patterns in seven participants with four masker stimulation configurations: monopolar (MP), partial tripolar (pTP), a wider partial tripolar (pTP + 2), and, importantly, a condition (RP + 2) designed to produce a broader excitation pattern than MP. The probe was always in partial-tripolar configuration.

RESULTS

We found a significant effect of stimulation configuration on both the amount of on-site masking (mask and probe on same electrode; an indirect indicator of sharpness) and the difference between off-site and on-site masking. Differences were driven solely by RP + 2 producing a broader excitation pattern than the other configurations, whereas monopolar and the two current-focussing configurations did not statistically differ from each other.

CONCLUSION

A method that is sensitive enough to reveal a modest broadening in RP + 2 showed no evidence for sharpening with focussed stimulation. We also showed that although voltage recordings from the implant accurately predicted a broadening of the psychophysical excitation patterns with RP + 2, they wrongly predicted a strong sharpening with pTP + 2. We additionally argue, based on our recent research, that the interleaved-masking method can usefully be applied to non-human species and objective measures of CI excitation patterns.

Individual Patient Comorbidities and Effect on Cochlear Implant Performance

OBJECTIVE

To examine the association between preoperative comorbidities and cochlear implant speech outcomes.

STUDY DESIGN

Retrospective cohort.

SETTING

Tertiary referral center.

PATIENTS

A total of 976 patients who underwent cochlear implantation (CI) between January 2015 and May 2022. Adult patients with follow-up, preoperative audiologic data, and a standardized anesthesia preoperative note were included.

EXPOSURE

Adult Comorbidity Evaluation 27 (ACE-27) based on standardized anesthesia preoperative notes.

MAIN OUTCOME MEASURES

Postoperative change in consonant-nucleus-consonant (CNC) score, AzBio Sentence score in quiet, and AzBio + 10 dB signal-to-noise ratio (SNR). Sentence score of the implanted ear at 3, 6, and 12 months.

RESULTS

A total of 560 patients met inclusion criteria; 112 patients (20%) had no comorbidity, 204 patients (36.4%) had mild comorbidities, 161 patients (28.8%) had moderate comorbidities, and 83 patients (14.8%) had severe comorbidities. Mixed model analysis revealed all comorbidity groups achieved a clinically meaningful improvement in all speech outcome measures over time. This improvement was significantly different between comorbidity groups over time for AzBio Quiet ( p = 0.045) and AzBio + 10 dB SNR ( p = 0.0096). Patients with severe comorbidities had worse outcomes. From preop to 12 months, the estimated marginal mean difference values (95% confidence interval) between the no comorbidity group and the severe comorbidity group were 52.3 (45.7-58.9) and 32.5 (24.6-40.5), respectively, for AzBio Quiet; 39.5 (33.8-45.2) and 21.2 (13.6-28.7), respectively, for AzBio + 10 dB SNR; and 43.9 (38.7-49.0) and 31.1 (24.8-37.4), respectively, for CNC.

CONCLUSIONS

Comorbidities as assessed by ACE-27 are associated with CI performance. Patients with more severe comorbidities have clinically meaningful improvement but have worse outcome compared to patients with no comorbidities.

Measuring speech intelligibility with deaf and hard-of-hearing children: A systematic review

There is great variability in the ways in which the speech intelligibility of d/Deaf and hard-of-hearing (DHH) children who use spoken language as part, or all, of their communication system is measured. This systematic review examined the measures and methods that have been used when examining the speech intelligibility of children who are DHH and the characteristics of these measures and methods. A systematic database search was conducted of CENTRAL; CINAHL; Cochrane; ERIC; Joanna Briggs; Linguistics, Language and Behavior Abstracts; Medline; Scopus; and Web of Science databases, as well as supplemental searches. A total of 204 included studies reported the use of many different measures/methods which measured segmental aspects of speech, with the most common being Allen et al.'s (2001, The reliability of a rating scale for measuring speech intelligibility following pediatric cochlear implantation. Otology and Neurotology, 22(5), 631-633. https://doi.org/10.1097/00129492-200109000-00012) Speech Intelligibility Rating scale. Many studies included insufficient details to determine the measure that was used. Future research should utilize methods/measures with known psychometric validity, provide clear descriptions of the methods/measures used, and consider using more than one measure to account for limitations inherent in different methods of measuring the speech intelligibility of children who are DHH, and consider and discuss the rationale for the measure/method chosen.

Artifact removal by template subtraction enables recordings of the frequency following response in cochlear-implant users

Electrically evoked frequency-following responses (eFFRs) provide insight in the phase-locking ability of brainstem of cochlear-implant (CI) users. eFFRs can potentially be used to gain insight in the individual differences in the biological limitation on temporal encoding of the electrically stimulated auditory pathway, which can be inherent to the electrical stimulation itself and/or the degenerative processes associated with hearing loss. One of the major challenge of measuring eFFRs in CI users is the process of isolating the stimulation artifact from the neural response, as both the response and the artifact overlap in time and have similar frequency characteristics. Here we introduce a new artifact removal method based on template subtraction that successfully removes the stimulation artifacts from the recordings when CI users are stimulated with pulse trains from 128 to 300 pulses per second in a monopolar configuration. Our results show that, although artifact removal was successful in all CI users, the phase-locking ability of the brainstem to the different pulse rates, as assessed with the eFFR differed substantially across participants. These results show that the eFFR can be measured, free from artifacts, in CI users and that they can be used to gain insight in individual differences in temporal processing of the electrically stimulated auditory pathway.

A frequency peak at 3.1 kHz obtained from the spectral analysis of the cochlear implant electrocochleography noise

INTRODUCTION

The functional evaluation of auditory-nerve activity in spontaneous conditions has remained elusive in humans. In animals, the frequency analysis of the round-window electrical noise recorded by means of electrocochleography yields a frequency peak at around 900 to 1000 Hz, which has been proposed to reflect auditory-nerve spontaneous activity. Here, we studied the spectral components of the electrical noise obtained from cochlear implant electrocochleography in humans.

METHODS

We recruited adult cochlear implant recipients from the Clinical Hospital of the Universidad de Chile, between the years 2021 and 2022. We used the AIM System from Advanced Bionics® to obtain single trial electrocochleography signals from the most apical electrode in cochlear implant users. We performed a protocol to study spontaneous activity and auditory responses to 0.5 and 2 kHz tones.

RESULTS

Twenty subjects including 12 females, with a mean age of 57.9 ± 12.6 years (range between 36 and 78 years) were recruited. The electrical noise of the single trial cochlear implant electrocochleography signal yielded a reliable peak at 3.1 kHz in 55% of the cases (11 out of 20 subjects), while an oscillatory pattern that masked the spectrum was observed in seven cases. In the other two cases, the single-trial noise was not classifiable. Auditory stimulation at 0.5 kHz and 2.0 kHz did not change the amplitude of the 3.1 kHz frequency peak.

CONCLUSION

We found two main types of noise patterns in the frequency analysis of the single-trial noise from cochlear implant electrocochleography, including a peak at 3.1 kHz that might reflect auditory-nerve spontaneous activity, while the oscillatory pattern probably corresponds to an artifact.

Predictors of Emotional Prosody Identification by School-Age Children With Cochlear Implants and Their Peers With Normal Hearing

OBJECTIVES

Children with cochlear implants (CIs) vary widely in their ability to identify emotions in speech. The causes of this variability are unknown, but this knowledge will be crucial if we are to design improvements in technological or rehabilitative interventions that are effective for individual patients. The objective of this study was to investigate how well factors such as age at implantation, duration of device experience (hearing age), nonverbal cognition, vocabulary, and socioeconomic status predict prosody-based emotion identification in children with CIs, and how the key predictors in this population compare to children with normal hearing who are listening to either normal emotional speech or to degraded speech.

DESIGN

We measured vocal emotion identification in 47 school-age CI recipients aged 7 to 19 years in a single-interval, 5-alternative forced-choice task. None of the participants had usable residual hearing based on parent/caregiver report. Stimuli consisted of a set of semantically emotion-neutral sentences that were recorded by 4 talkers in child-directed and adult-directed prosody corresponding to five emotions: neutral, angry, happy, sad, and scared. Twenty-one children with normal hearing were also tested in the same tasks; they listened to both original speech and to versions that had been noise-vocoded to simulate CI information processing.

RESULTS

Group comparison confirmed the expected deficit in CI participants' emotion identification relative to participants with normal hearing. Within the CI group, increasing hearing age (correlated with developmental age) and nonverbal cognition outcomes predicted emotion recognition scores. Stimulus-related factors such as talker and emotional category also influenced performance and were involved in interactions with hearing age and cognition. Age at implantation was not predictive of emotion identification. Unlike the CI participants, neither cognitive status nor vocabulary predicted outcomes in participants with normal hearing, whether listening to original speech or CI-simulated speech. Age-related improvements in outcomes were similar in the two groups. Participants with normal hearing listening to original speech showed the greatest differences in their scores for different talkers and emotions. Participants with normal hearing listening to CI-simulated speech showed significant deficits compared with their performance with original speech materials, and their scores also showed the least effect of talker- and emotion-based variability. CI participants showed more variation in their scores with different talkers and emotions than participants with normal hearing listening to CI-simulated speech, but less so than participants with normal hearing listening to original speech.

CONCLUSIONS

Taken together, these results confirm previous findings that pediatric CI recipients have deficits in emotion identification based on prosodic cues, but they improve with age and experience at a rate that is similar to peers with normal hearing. Unlike participants with normal hearing, nonverbal cognition played a significant role in CI listeners' emotion identification. Specifically, nonverbal cognition predicted the extent to which individual CI users could benefit from some talkers being more expressive of emotions than others, and this effect was greater in CI users who had less experience with their device (or were younger) than CI users who had more experience with their device (or were older). Thus, in young prelingually deaf children with CIs performing an emotional prosody identification task, cognitive resources may be harnessed to a greater degree than in older prelingually deaf children with CIs or than children with normal hearing.

Music Perception in Bone-Anchored Hearing Implant Users

OBJECTIVE

Music is a highly complex acoustic stimulus in both spectral and temporal contents. Accurate representation and delivery of high-fidelity information are essential for music perception. However, it is unclear how well bone-anchored hearing implants (BAHIs) transmit music. The study objective is to establish music perception performance baselines for BAHI users and normal hearing (NH) listeners and compare outcomes between the cohorts.

METHODS

A case-controlled, cross-sectional study was conducted among 18 BAHI users and 11 NH controls. Music perception was assessed via performance on seven major musical element tasks: pitch discrimination, melodic contour identification, rhythmic clocking, basic tempo discrimination, timbre identification, polyphonic pitch detection, and harmonic chord discrimination.

RESULTS

BAHI users performed comparably well on all music perception tasks with their device compared with the unilateral condition with their better-hearing ear. BAHI performance was not statistically significantly different from NH listeners' performance. BAHI users performed just as well, if not better than NH listeners when using their control contralateral ear; there was no significant difference between the two groups except for the rhythmic timing (BAHI non-implanted ear 69% [95% CI: 62%-75%], NH 56% [95% CI: 49%-63%], p = 0.02), and basic tempo tasks (BAHI non-implanted ear 80% [95% CI: 65%-95%]; NH 75% [95% CI: 68%-82%, p = 0.03]).

CONCLUSIONS

This study represents the first comprehensive study of basic music perception performance in BAHI users. Our results demonstrate that BAHI users perform as well with their implanted ear as with their contralateral better-hearing ear and NH controls in the major elements of music perception.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:1381-1387, 2024.

Parameterisation and Prediction of Intra-canal Cochlear Structures

Accurate 3D models of the cochlea are useful tools for research in the relationship between the electrode array and nerve fibres. The internal geometry of the cochlear canal plays an important role in understanding and quantifying that relationship. Predicting the location and shapes of the geometry is done by measuring histologic sections and fitting equations that can be used to predict parameters that fully define the geometry. A parameter sensitivity analysis is employed to prove that the size and location of the spiral lamina are the characteristics that most influence current distribution along target nerve fibres. The proposed landmark prediction method more accurately predicts the location of the points defining the spiral lamina in the apical region of the cochlea than methods used in previous modelling attempts. Thus, this technique can be used to generate 2D geometries that can be expanded to 3D models when high-resolution imaging is not available.

Revisiting the effect of text complexity on Continuous Discourse Tracking using synthetic speech: Old tricks with new dogs

Continuous Discourse Tracking (CDT) is a functional test of speech perceptual ability, which has been criticised on account of the procedural variation inherent in the method. This study sought to reduce this variation by using synthetic speech, which was subsequently vocoded to simulate listening with a cochlear implant. We also assessed the complexity of three text excerpts with auditory (n = 10) and written Cloze tests (n = 10). These same passages were used in an auditory-only CDT experiment (n = 12) performed with the synthetic-vocoded material. Mean tracking rates were lower, and the number of blockages was higher for the most difficult text as determined by the Cloze results. We also noted some anomalous realisations from the speech synthesis, but these were unlikely to have contributed to the differences in tracking rates that were observed for text complexity. These results show that Cloze testing is suitable to predict text complexity for CDT performed with synthesised speech. Furthermore, they indicate that the use of text-speech synthesis is viable and may be a useful addition to rehabilitation where functional measures are used to assess communication aptitude.

Cochlear Implantation in Children With a Long Average Duration of Single Sided Deafness

OBJECTIVES

Previous research has shown the positive effects of cochlear implantation in children with a short duration of single sided deafness (SSD). This case series assessed the impact of cochlear implantation in a cohort of children with a longer average duration of SSD.

METHODS

A retrospective chart review of 6 children who received a cochlear implant for SSD. The mean age at time of cochlear implantation was 14.7 years old (median = 15.5, interquartile range (IQR) = 2.5) and mean duration of hearing loss before cochlear implantation was 10.8 years (median = 11.5, IQR = 5.3). Pre- and post-operative audiometric data for aided speech perception testing, sentence recognition in quiet, sentence recognition in noise, and word recognition scores were analyzed.

RESULTS

When compared to preoperative hearing aid scores a 24% significant increase in median word score and a 64% significant increase in median sentence recognition score in quiet was observed at 12 months post-op.

CONCLUSION

Cochlear implantation in children with a longer duration of SSD can provide benefit to speech recognition.

LAY SUMMARY

This retrospective case series of children with prolonged single sided deafness demonstrated an improvement in word and sentence recognition within 12 months of receiving a cochlear implant.

Lexical effects on talker discrimination in adult cochlear implant usersa)

The lexical and phonological content of an utterance impacts the processing of talker-specific details in normal-hearing (NH) listeners. Adult cochlear implant (CI) users demonstrate difficulties in talker discrimination, particularly for same-gender talker pairs, which may alter the reliance on lexical information in talker discrimination. The current study examined the effect of lexical content on talker discrimination in 24 adult CI users. In a remote AX talker discrimination task, word pairs-produced either by the same talker (ST) or different talkers with the same (DT-SG) or mixed genders (DT-MG)-were either lexically easy (high frequency, low neighborhood density) or lexically hard (low frequency, high neighborhood density). The task was completed in quiet and multi-talker babble (MTB). Results showed an effect of lexical difficulty on talker discrimination, for same-gender talker pairs in both quiet and MTB. CI users showed greater sensitivity in quiet as well as less response bias in both quiet and MTB for lexically easy words compared to lexically hard words. These results suggest that CI users make use of lexical content in same-gender talker discrimination, providing evidence for the contribution of linguistic information to the processing of degraded talker information by adult CI users.

Localization of Low- and High-Frequency Sounds in Cochlear Implant Recipients Using a Contralateral Hearing Aid

BACKGROUND AND OBJECTIVES

The ability to localize sounds is partly recovered in patients using a cochlear implant (CI) in one ear and a hearing aid (HA) on the contralateral side. Binaural processing seems effective at least to some extent, despite the difference between electric and acoustic stimulation in each ear. To obtain further insights into the mechanisms of binaural hearing in these listeners, localization of low- and high-frequency sounds was tested.

STUDY DESIGN

The study used a within-subject design, where participants were tasked with localizing sound sources in the horizontal plane. The experiment was conducted in an anechoic chamber, where an array of seven loudspeakers was mounted along the 24 azimuthal angle span from -90° to +90°. Stimuli were applied with different frequencies: broadband noise and high- and low-frequency noise.

SUBJECTS

Ten CI recipients participated in the study. All had an asymmetric hearing loss with a CI in the poorer ear and an HA on the contralateral side.

MAIN OUTCOME MEASURES

Accuracy of sound localization in terms of angular error and percentage of correct localization scores.

RESULTS

The median angular error was 40° in bimodal conditions for both broadband noise and high-frequency noise stimuli. The angular error increased to 47° for low-frequency noise stimuli. In the unilaterally aided condition with an HA, only a median angular error of 78° was observed.

CONCLUSIONS

Irrespective of the frequency composition of the stimuli, this group of bimodal listeners showed some ability to localize sounds. Angular errors were larger than those reported in the literature for bilateral CI users or single-sided deaf listeners with a CI. In the unilateral listening condition with HA, only localization of sounds was not possible for most subjects.

Long-term outcomes and electrophysiological measures of children with inner ear malformations and cochlear implants

OBJECTIVES

To compared auditory and speech performance outcomes of children with cochlear implants (CI), between those with inner ear malformations (IEMs) and with normal ear anatomy; and to describe differences in electrophysiological measurements.

STUDY DESIGN

A retrospective study.

SETTING

A tertiary care pediatric medical center.

PATIENTS

Forty-one children with IEMs who underwent CI during 2003-2017, and 41 age-matched CI recipients with normal ear anatomy (control group).

MAIN OUTCOME MEASURES

Post-CI auditory performance outcomes including educational setting, Categories of Auditory Performance (CAP), and Speech Intelligibility Rating (SIR); and electrophysiological measurements, Including maximal comfortable electrical levels (CLs) and impedances along CI electrodes.

RESULTS

The ANOVA on ranks revealed lower CAP scores in the study than control group: H3 = 18.8, P < 0.001. Among children with IEMs, CAP scores were better in children with enlarged vestibular aqueduct (EVA) (P < 0.04). SIR scores of the control group did not differ from those with isolated EVA; however, SIR scores of the IEMs without EVA subgroup were lower than all the other study subgroups (P < 0.01). The proportion of the control group that was integrated with full inclusion educational settings into the regular mainstream schools was higher than for those with IEMs without EVA (47 % vs. 15 %, P < 0.05), but similar to those with isolated EVA. For the study group versus control group, maximal comfortable electrical levels (CLs) were higher)P > 0.03) while impedance measurements were similar.

CONCLUSIONS

Outcomes of pediatric recipients with normal anatomy were better than those with IEMs. Among pediatric recipients of CI with IEMs, auditory performance was better and CLs were lower among children with isolated EVA than all other IEM subgroups.

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.

Listening evaluation of cochlear implant users: comparison of subjective and objective evaluation by visual analogue scale

OBJECTIVE

This study aimed to use short-form visual analogue scale cochlear implantation questionnaires to evaluate subjective aspects at each out-patient visit. The correlation between subjective hearing tests using the short-form visual analogue scale and objective hearing outcomes was evaluated.

METHOD

This study was conducted in a single centre. Cochlear implant users (n = 199) evaluated their hearing on a scale of 0 to 100 for the right, left and both ears. The Japanese speech perception test (CI-2004) Japanese monosyllable speech perception test (67-S) and cochlear implantation threshold were used for the objective cochlear implantation evaluation.

RESULTS

A significant correlation was found between the short-form visual analogue scale questionnaire and objective hearing outcome, for words (r = 0.64) and sentences (r = 0.62) in CI-2004 and 67-S (r = 0.56) tests. No significant correlation was found between the short-form visual analogue scale score and cochlear implantation threshold (r = -0.18).

CONCLUSION

Short-form visual analogue scale cochlear implantation questionnaires mean cochlear implant users spend less time answering subjective visual analogue scale questionnaires, and clinicians estimate a patient's cochlear implantation hearing and abnormality by chronological evaluation.

InterlACE Sound Coding for Unilateral and Bilateral Cochlear Implants

OBJECTIVE

Cochlear implant signal processing strategies define the rules of how acoustic signals are converted into electrical stimulation patterns. Technological and anatomical limitations, however, impose constraints on the signal transmission and the accurate excitation of the auditory nerve. Acoustic signals are degraded throughout cochlear implant processing, and electrical signal interactions at the electrode-neuron interface constrain spectral and temporal precision. In this work, we propose a novel InterlACE signal processing strategy to counteract the occurring limitations.

METHODS

By replacing the maxima selection of the Advanced Combination Encoder strategy with a method that defines spatially and temporally alternating channels, InterlACE can compensate for discarded signal content of the conventional processing. The strategy can be extended bilaterally by introducing synchronized timing and channel selection. InterlACE was explored unilaterally and bilaterally by assessing speech intelligibility and spectral resolution. Five experienced bilaterally implanted cochlear implant recipients participated in the Oldenburg Sentence Recognition Test in background noise and the spectral ripple discrimination task.

RESULTS

The introduced alternating channel selection methodology shows promising outcomes for speech intelligibility but could not indicate better spectral ripple discrimination.

CONCLUSION

InterlACE processing positively affects speech intelligibility, increases available unilateral and bilateral signal content, and may potentially counteract signal interactions at the electrode-neuron interface.

SIGNIFICANCE

This work shows how cochlear implant channel selection can be modified and extended bilaterally. The clinical impact of the modifications needs to be explored with a larger sample size.

Objective intelligibility measurement of reverberant vocoded speech for normal-hearing listeners: Towards facilitating the development of speech enhancement algorithms for cochlear implants

Cochlear implant (CI) recipients often struggle to understand speech in reverberant environments. Speech enhancement algorithms could restore speech perception for CI listeners by removing reverberant artifacts from the CI stimulation pattern. Listening studies, either with cochlear-implant recipients or normal-hearing (NH) listeners using a CI acoustic model, provide a benchmark for speech intelligibility improvements conferred by the enhancement algorithm but are costly and time consuming. To reduce the associated costs during algorithm development, speech intelligibility could be estimated offline using objective intelligibility measures. Previous evaluations of objective measures that considered CIs primarily assessed the combined impact of noise and reverberation and employed highly accurate enhancement algorithms. To facilitate the development of enhancement algorithms, we evaluate twelve objective measures in reverberant-only conditions characterized by a gradual reduction of reverberant artifacts, simulating the performance of an enhancement algorithm during development. Measures are validated against the performance of NH listeners using a CI acoustic model. To enhance compatibility with reverberant CI-processed signals, measure performance was assessed after modifying the reference signal and spectral filterbank. Measures leveraging the speech-to-reverberant ratio, cepstral distance and, after modifying the reference or filterbank, envelope correlation are strong predictors of intelligibility for reverberant CI-processed speech.

Preoperative EABR evaluation of auditory pathway integrity in patients with different etiology and postoperative effect estimation

OBJECTIVES

To evaluate the effect of electrical auditory brainstem response (EABR) on the integrity evaluation of auditory pathway and the prediction of postoperative effect of cochlear implantation in patients with different etiology of hearing loss.

METHODS

A total of 580 patients with neuropathic deafness who underwent cochlear implantation surgery from August 2011 to December 2020 were selected for EABR test. The preoperative EABR waveform was analyzed, and parameters such as V wave amplitude, threshold, latency and interval of each wave, and slope of V wave I/O curve were measured. Neural response telemetry (NRT) test was performed during MAP 1 month after operation, and C and T values of the machine were recorded.

RESULTS

The total EABR extraction rate was 98.45% among 580 patients, including 100% for the normal structure group and enlarged vestibular aqueduct group (LVAS), 92.44% for other malformed group. The average threshold of V wave in patients with normal cochlear structure was significantly better than the malformation groups (p < 0.05). The total extraction rate of NRT was 78.62%, including 99.72% in the group with normal structure, 95.65% in the LVAS group, 1.85-88.24% in the group with other malformations, and 0% in the cochlear ossification group. The correlation analysis showed a statistically significant correlation between the average preoperative EABR threshold and the C value of NRT.

CONCLUSIONS

Preoperative EABR could evaluate the integrity of auditory conduction pathway of patients with cochlear implantation and predict the postoperative hearing rehabilitation effect.

Treatment of Meniere's disease with simultaneous triple semicircular canal occlusion and cochlear implantation

OBJECTIVE

Report three cases of simultaneous triple semicircular canal occlusion (TSCO) and cochlear implantation (CI) as the treatment of intractable Meniere's disease (MD).

CASE REPORTS

Patients with MD can present occasionally with intractable vertigo and profound sensorineural hearing loss (SNHL). TSCO and CI have been proposed to control vertigo and restore profound deafness in patients with MD separately. However, a few studies have reported simultaneous TSCO and CI in the same surgical procedure for the treatment of MD. In the present study, we described three patients with MD showing incapacitating vertigo and severe SNHL who underwent simultaneous TSCO and CI after examinations of auditory system, vestibular system, and imaging. Their symptoms were significantly alleviated during the follow-up period.

CONCLUSION

The combined TSCO and CI remains a viable treatment option which is effective for the control of vertigo as well as the restoring of hearing in patients with MD.

Radioclinical Assessment of Posterior Tympanotomy Difficulties during Ordinary Cochlear Implantation: A Prospective Case-Series Study

OBJECTIVES

This study proposes a preoperative radiologic scoring system for predicting posterior tympanotomy (PT) and mastoidectomy-associated difficulties during cochlear implantation (CI).

STUDY DESIGN

It was a prospective case-series study.

SETTINGS

The included CI surgeries were performed at tertiary referral institutions from October 2022 to April 2023.

SUBJECTS

We included 73 CI candidates performed via the PT approach.

INTERVENTION

The proposed radiologic score, composed of 13 items, was fulfilled and evaluated before each CI surgery.

MAIN OUTCOME MEASURE

We correlated this score with the intraoperative difficulty and surgical duration.

RESULTS

The operation was straightforward in 42 patients with a score of 3.87 ± 1.72 and challenging in 31 patients with a score of 10.66 ± 1.73. The radiologic score was strongly correlated with the surgical difficulty and duration (p < 0.0001).

CONCLUSIONS

Our proposed radiologic score was a valid, reliable, and precise tool to predict intraoperative difficulty during cochlear implantation. Chorda-facial angle was the strongest predictor, significantly affecting the difficulty, surgical duration, and preoperative radiologic score. A score equal to or more than 7.5 was expected to be associated with surgical difficulty.

Outcomes of cochlear implantation in Usher syndrome: a systematic review

PURPOSE

This study is a systematic review of the literature which seeks to evaluate auditory and quality of life (QOL) outcomes of cochlear implantation in patients with Usher syndrome.

METHODS

Systematic review of studies indexed in Medline via PubMed, Ovid EMBASE, Web of Science, CENTRAL and clinicaltrials.gov was performed up to March 9th 2022, conducted in accordance with the PRISMA statement. Patient demographics, comorbidity, details of cochlear implantation, auditory, and QOL outcomes were extracted and summarized.

RESULTS

33 studies reported over 217 cochlear implants in 187 patients with Usher syndrome, comprising subtypes 1 (56 patients), 2 (9 patients), 3 (23 patients), and not specified (99 patients). Auditory outcomes included improved sound detection, speech perception, and speech intelligibility. QOL outcomes were reported for 75 patients, with benefit reported in the majority.

CONCLUSIONS

Many patients with Usher syndrome develop improved auditory outcomes after cochlear implantation with early implantation being an important factor.

Effects of the BalanCI on Working Memory and Balance in Children and Young Adults With Cochleovestibular Dysfunction

OBJECTIVES

This study aimed to: (1) determine the interaction between cognitive load and balance in children and young adults with bilateral cochleovestibular dysfunction who use bilateral cochlear implants (CIs) and (2) determine the effect of an auditory balance prosthesis (the BalanCI) on this interaction. Many (20 to 70%) children with sensorineural hearing loss experience some degree of vestibular loss, leading to poorer balance. Poor balance could have effects on cognitive resource allocation which might be alleviated by the BalanCI as it translates head-referenced cues into electrical pulses delivered through the CI. It is hypothesized that children and young adults with cochleovestibular dysfunction will demonstrate greater dual-task costs than typically-developing children during dual balance-cognition tasks, and that BalanCI use will improve performance on these tasks.

DESIGN

Study participants were 15 typically-developing children (control group: mean age ± SD = 13.6 ± 2.75 years, 6 females) and 10 children and young adults who use bilateral CIs and have vestibular dysfunction (CI-V group: mean age ± SD=20.6 ± 5.36 years, 7 females). Participants completed two working memory tasks (backward auditory verbal digit span task and backward visuospatial dot matrix task) during three balance conditions: seated, standing in tandem stance with the BalanCI off, and standing in tandem stance with the BalanCI on. Working memory performance was quantified as total number of correct trials achieved. Postural stability was quantified as translational and rotational path length of motion capture markers worn on the head, upper body, pelvis, and feet, normalized by trial time.

RESULTS

Relative to the control group, children and young adults in the CI-V group exhibited poorer overall working memory across all balance conditions ( p = 0.03), poorer translational postural stability (larger translational path length) during both verbal and visuospatial working memory tasks ( p < 0.001), and poorer rotational stability (larger rotational path length) during the verbal working memory task ( p = 0.026). The CI-V group also exhibited poorer translational ( p = 0.004) and rotational ( p < 0.001) postural stability during the backward verbal digit span task than backward visuospatial dot matrix task; BalanCI use reduced this stability difference between verbal and visuospatial working memory tasks for translational stability overall ( p > 0.9), as well as for rotational stability during the maximum working memory span (highest load) participants achieved in each task ( p = 0.91).

CONCLUSIONS

Balance and working memory were impaired in the CI-V group compared with the control group. The BalanCI offered subtle improvements in stability in the CI-V group during a backward verbal working memory task, without producing a negative effect on working memory outcomes. This study supports the feasibility of the BalanCI as a balance prosthesis for individuals with cochleovestibular impairments.