Hearing Restoration in Cochlear Nerve Deficiency: the Choice Between Cochlear Implant or Auditory Brainstem Implant, a Meta-analysis

Cochlear Implantation Outcomes in Genotyped Subjects with Sensorineural Hearing Loss

PURPOSE

Cochlear implants (CIs) are an effective rehabilitation option for individuals with severe-to-profound sensorineural hearing loss (SNHL). While genetic factors play a significant role in SNHL, the variability in CI outcomes remains unclear. This study evaluated short- and long-term CI outcomes in a large genotyped cohort and investigated correlations with genetic defects and their cochlear site-of-lesion.

METHODS

This retrospective, single-center, cohort study included 220 subjects (127 females; 299 ears) with pathogenic variants identified in 31 different nuclear genes and in mitochondrial genes. Audiological outcomes were measured pre- and post-implantation. Cochlear site-of-lesion was categorized as pre-synaptic, post-synaptic, or mitochondrial, based on gene function or expression. Multiple regression analysis assessed factors influencing outcomes, including age at implantation, SNHL duration, hearing aid (HA) use, and cochlear site-of-lesion.

RESULTS

Results showed a median phoneme score of 90%, with better outcomes in early implantation (≤ 6 years). Variability in outcomes was not linked to cochlear site-of-lesion, but to subject-specific factors, such as age at implantation, duration of SNHL, pre-implantation HA use, and CI experience. A model incorporating these subject-specific factors explained 19% of the total variance in outcomes. Poorer outcomes (phoneme scores < 70%) were more common in individuals with prolonged auditory deprivation or older age at implantation.

CONCLUSION

Genotyped CI recipients demonstrated excellent outcomes, with variability largely attributed to non-genetic factors. These findings show that cochlear implantation is a beneficial type of rehabilitation for most individuals with hereditary SNHL and underscore the importance of early implantation.

Intraoperative Assessment of Cochlear Nerve Function During Cochlear Implantation Using the Auditory Nerve Test Stimulator

BACKGROUND/OBJECTIVES

A crucial factor for a successful cochlear implant (CI) outcome is an intact auditory nerve (AN). The integrity of the AN can be tested during implantation by measuring electrical auditory brainstem responses (eABR) via the CI. A method that does not require a CI is the use of the auditory nerve test stimulator (ANTS) from MED-EL (Innsbruck, Austria). The aim of the current study was to investigate the cases tested with the ANTS at our clinic and to describe the hearing results following CI for the cases who were implanted with a CI.

METHODS

All patients underwent preoperative magnetic resonance imaging (MRI) and high-resolution computed tomography (HRCT) to rule out cochlear malformation or retrocochlear pathology. In this study, we described all cases from when we began using the ANTS in 2011.

RESULTS

Five patients were tested intraoperatively: three adults with long-term deafness prior to CI and two children with no detectable AN. Three of the five patients were implanted with a CI. All implanted patients in this study could hear with their CIs, even though the speech perception results were limited.

CONCLUSIONS

The ANTS can be used as a method to assess cochlear nerve function during implantation. The eABR results from the ANTS and the implanted CI were comparable for all cases in our study. Minor changes in waveform latencies were found between ANTS and CI stimulation and may be explained by the insertion depth of the electrode used for stimulation.

Brazilian Society of Otology task force - single sided deafness - recommendations based on strength of evidence

OBJECTIVE

To make evidence-based recommendations for the treatment of Single-Sided Deafness (SSD) in children and adults.

METHODS

Task force members were instructed on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on SSD were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 3 parts: (1) Impact of SSD in children; (2) Impact of SSD in adults; and (3) SSD in patients with temporal bone tumors.

CONCLUSIONS

Decision-making for patients with SSD is complex and multifactorial. The lack of consensus on the quality of outcomes and on which measurement tools to use hinders a proper comparison of different treatment options. Contralateral routing of signal hearing aids and bone conduction devices can alleviate the head shadow effect and improve sound awareness and signal-to-noise ratio in the affected ear. However, they cannot restore binaural hearing. Cochlear implants can restore binaural hearing, producing significant improvements in speech perception, spatial localization of sound, tinnitus control, and overall quality of life. However, cochlear implantation is not recommended in cases of cochlear nerve deficiency, a relatively common cause of congenital SSD.

Brazilian Society of Otology task force - cochlear implant ‒ recommendations based on strength of evidence

OBJECTIVE

To make evidence-based recommendations for the indications and complications of Cochlear Implant (CI) surgery in adults and children.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on cochlear implantation were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Evaluation of candidate patients and indications for CI surgery; (2) CI surgery - techniques and complications.

CONCLUSIONS

CI is a safe device for auditory rehabilitation of patients with severe-to-profound hearing loss. In recent years, indications for unilateral hearing loss and vestibular schwannoma have been expanded, with encouraging results. However, for a successful surgery, commitment of family members and patients in the hearing rehabilitation process is essential.

Long-Term Outcomes of Cochlear Implantation in Usher Syndrome

OBJECTIVES

Usher syndrome (USH), characterized by bilateral sensorineural hearing loss (SNHL) and retinitis pigmentosa (RP), prompts increased reliance on hearing due to progressive visual deterioration. It can be categorized into three subtypes: USH type 1 (USH1), characterized by severe to profound congenital SNHL, childhood-onset RP, and vestibular areflexia; USH type 2 (USH2), presenting with moderate to severe progressive SNHL and RP onset in the second decade, with or without vestibular dysfunction; and USH type 3 (USH3), featuring variable progressive SNHL beginning in childhood, variable RP onset, and diverse vestibular function. Previous studies evaluating cochlear implant (CI) outcomes in individuals with USH used varying or short follow-up durations, while others did not evaluate outcomes for each subtype separately. This study evaluates long-term CI performance in subjects with USH, at both short-term and long-term, considering each subtype separately.

DESIGN

This retrospective, observational cohort study identified 36 CI recipients (53 ears) who were categorized into four different groups: early-implanted USH1 (first CI at ≤7 years of age), late-implanted USH1 (first CI at ≥8 years of age), USH2 and USH3. Phoneme scores at 65 dB SPL with CI were evaluated at 1 year, ≥2 years (mid-term), and ≥5 years postimplantation (long-term). Each subtype was analyzed separately due to the significant variability in phenotype observed among the three subtypes.

RESULTS

Early-implanted USH1-subjects (N = 23 ears) achieved excellent long-term phoneme scores (100% [interquartile ranges {IQR} = 95 to 100]), with younger age at implantation significantly correlating with better CI outcomes. Simultaneously implanted subjects had significantly better outcomes than sequentially implanted subjects ( p = 0.028). Late-implanted USH1 subjects (N = 3 ears) used CI solely for sound detection and showed a mean phoneme discrimination score of 12% (IQR = 0 to 12), while still expressing satisfaction with ambient sound detection. In the USH2 group (N = 23 ears), a long-term mean phoneme score of 85% (IQR = 81 to 95) was found. Better outcomes were associated with younger age at implantation and higher preimplantation speech perception scores. USH3-subjects (N = 7 ears) achieved a mean postimplantation phoneme score of 71% (IQR = 45 to 91).

CONCLUSIONS

This study is currently one of the largest and most comprehensive studies evaluating CI outcomes in individuals with USH, demonstrating that overall, individuals with USH benefit from CI at both short- and long-term follow-up. Due to the considerable variability in phenotype observed among the three subtypes, each subtype was analyzed separately, resulting in smaller sample sizes. For USH1 subjects, optimal CI outcomes are expected with early simultaneous bilateral implantation. Late implantation in USH1 provides signaling function, but achieved speech recognition is insufficient for oral communication. In USH2 and USH3, favorable CI outcomes are expected, especially if individuals exhibit sufficient speech recognition with hearing aids and receive ample auditory stimulation preimplantation. Early implantation is recommended for USH2, given the progressive nature of hearing loss and concomitant severe visual impairment. In comparison with USH2, predicting outcomes in USH3 remains challenging due to the variability found. Counseling for USH2 and USH3 should highlight early implantation benefits and encourage hearing aid use.

Efficacy of cochlear implantation in cochlear nerve deficiency children - A single center study

PURPOSES

The objective of this research was to interpret and analyze the imaging, audiological features and cochlear implantation outcomes in cochlear nerve deficiency children.

MATERIAL AND METHODS

Retrospective analysis.

RESULTS

25 prelingual hearing loss children diagnosed cochlear nerve deficiency (CND), the age range from 1 to 15 (mean age, 5.04), underwent cochlear implantation at Ear Nose and Throat Hospital - Ho Chi Minh City (ENT hospital - HCMC) from 2016 to 2023. All children had sensorineural hearing loss (SNHL) from severe to profound degree. Magnetic resonance imaging (MRI) showed cochlear nerve hypoplasia in 76 % and cochlear nerve aplasia in 24 % of cases. Inner ear malformations were found in 52 % of cases. The mean Categories of Auditory Performance (CAP) score at 1 year after surgery was 4.8. At 6 months and 1 year after surgery, the mean CAP score of the aplasia group was significantly lower than that of the hypoplasia group (p < 0.05).

CONCLUSIONS

In cochlear nerve deficiency children, auditory perception and speech performance still improved after cochlear implantation. However, this progress was significantly limited in cochlear nerve aplasia group.

Evaluation of Cochlear Implantation in Children With Cochlear Nerve Absence or Deficiency

OBJECTIVE

To identify associations between cochleovestibular anatomy findings and hearing outcomes found in children with imaging evidence of an absent or hypoplastic cochlear nerve treated with cochlear implantation (CI).

STUDY DESIGN

retrospective review.

SETTING

Cochlear implant program at tertiary care center.

METHODS

A retrospective review was performed to identify children with imaging evidence of cochlear nerve absence or deficiency who underwent CI evaluation. High-resolution 3-dimensional T2-weighted magnetic resonance imaging in the oblique sagittal and axial planes were reviewed by a neuroradiologist to identify cochleovestibular anatomy. Hearing was assessed pre and postoperatively with Speech Perception Category scores.

RESULTS

Seven CI recipients were identified (n = 10 ears) who had bilateral severe to profound sensorineural hearing loss with lack of auditory development with binaural hearing aid trial and imaging evidence of cochlear nerve aplasia/hypoplasia. All ears had 2 nerves in the cerebellopontine angle (100%, n = 10), half of the ears had evidence of 2 or less nerves in the internal auditory canal (IAC). All children showed large improvement in speech perception after CI.

CONCLUSION

Our experience with CIs for children with absent or hypoplastic cochlear nerves demonstrates that CI can be a viable option in select patients who satisfy preoperative audiological criteria. Radiological identification of a hypoplastic or aplastic cochlear nerve does not preclude auditory innervation of the cochlea. CI recipients in this subgroup must be counseled on difficulty in predicting postimplantation language and speech outcomes, and cautioned about facial nerve stimulation.

A Systematic Review and Meta-analysis Examining Outcomes of Cochlear Implantation in Children With Bilateral Cochlear Nerve Deficiency

OBJECTIVE

To assess hearing and speech outcomes in pediatric patients with bilateral cochlear nerve deficiency (CND) who underwent cochlear implantation (CI) and to identify factors associated with improved outcomes.

DATABASES REVIEWED

PubMed, Embase, Web of Science, and Cochran databases were searched following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

METHODS

Studies that reported hearing and speech outcomes of pediatric patients with bilateral CND who underwent CI were included. Demographics, comorbidities, inner ear abnormalities, CND classification (aplasia or hypoplasia), details of diagnostic workup, and outcomes data were extracted. Outcomes were assessed using the four-level auditory performance level (APL) scale. Meta-analysis, using Cochran-Armitage tests, was performed on patients with individual data to assess factors associated with performance.

RESULTS

A total of 314 papers were screened, and 40 papers with 378 total patients met inclusion criteria. A total of 339 patients had patient-level data and were included in the meta-analysis. Of the 339 patients, 19% (n = 63) of patients had no measurable stimulation, 28% (n = 95) had improved detection, 22% (n = 76) achieved closed-set speech perception, and 31% (n = 105) achieved open-set speech perception. Patients with cochlear nerve aplasia (p = 0.016) and syndromes (p < 0.001) had significantly worse APL scores relative to patients with cochlear nerve hypoplasia and patients without syndromes, respectively.

CONCLUSIONS

While most patients with bilateral CND benefit from CI and almost one-third of patients achieved open-set speech perception, outcomes were heterogenous and one-fifth of patients did not experience measurable benefit from CI.

Prognostic Value of Electrophysiological and MRI Findings for Pediatric Cochlear Implant Outcomes: A Systematic Review

PURPOSE

Magnetic resonance imaging (MRI), electric compound action potential (eCAP), and electric auditory brainstem response (eABR) are among the routine assessments performed before and/or after cochlear implantation. The objective of this review was to systematically summarize and critically appraise existing evidence of the prognostic value of eCAP, eABR, and MRI for predicting post-cochlear implant (CI) speech perception outcomes in children, with a particular focus on the lesion site.

METHOD

The present systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement. Three electronic databases (ProQuest, PubMed, and Scopus) were searched with no restrictions on language, publication status, or year of publication. Studies on children identified with sensorineural hearing loss, auditory neuropathy spectrum disorder, cochlear nerve deficiency, or cochleovestibular nerve abnormalities reporting the relevance of eCAP, eABR, and/or MRI results to CI speech perception outcomes were included. The literature search yielded 1,887 publications. Methodological quality and strength of evidence were assessed by the Crowe Critical Appraisal Tool and the Grading of Recommendations Assessment, Development, and Evaluation tool, respectively.

RESULTS

Of the 25 included studies, the relevance of eCAP, eABR, and/or MRI findings to post-CI speech perception outcomes was reported in 10, 11, and 11 studies, respectively. The studies were strongly in support of the prognostic value of eABR and MRI for CI outcomes. However, the relevance of eCAP findings to speech perception outcomes was uncertain.

CONCLUSION

Despite the promising findings, caution is warranted in interpreting them due to the observational and retrospective design of the included studies, as well as the heterogeneity of the population and the limited control of confounding factors within these studies.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26169859.

Clinical Portrait of Cochlear Implantation in Patients With CHARGE Syndrome

OBJECTIVE

To examine the clinical characteristics and auditory performance of patients with CHARGE syndrome following cochlear implantation (CI), as well as the prognostic factors affecting auditory outcomes.

STUDY DESIGN

Retrospective cohort.

SETTING

Tertiary academic center.

METHODS

A retrospective chart review was performed in patients with CHARGE syndrome who underwent CI from 2007 to 2022. The category of auditory performance (CAP) score was used to assess the CI outcomes, and factors that may affect the speech outcomes were also evaluated.

RESULTS

In 14 children with CHARGE syndrome, 22 CIs were performed, 6 unilaterally and 8 bilaterally. The mean age at CI was 25.9 months (range: 10-62). All patients had ear abnormalities and developmental delays, and cochlear nerve deficiency (CND) was present in all ears. At the last follow-up (mean: 49.6 months), the mean CAP score improved significantly compared to the preoperative measure (from 0.36 ± 0.81 to 3.21 ± 1.70, P = .001), with 6 patients (42.9%) achieving a CAP score of 4 points or higher. However, between the unilateral and bilateral CI groups, the final CAP score or change in CAP score was similar. Factors including age, coloboma, and CND did not significantly affect speech outcomes (all P > .05).

CONCLUSION

Even though CHARGE syndrome features challenging anomalies, CI can be conducted safely and can offer effective contribution to significant speech improvement. Patients with CHARGE syndrome should be given the opportunity to undergo CI to maximize their audiological progress.

Current status of pediatric auditory brainstem implantation in inner ear malformations; consensus statement of the Third International Pediatric ABI Meeting

OBJECTIVES

This study aims to synthesize current knowledge and outcomes related to pediatric auditory brainstem implantation (ABI) in children with severe inner ear malformations (IEMs). It highlights the clinical management practices, challenges, and potential future directions for consensus development in this field.

METHODS

A systematic review of findings presented at the Third International Pediatric ABI Symposium organized by the Hacettepe Cochlear Implant team between 3 and 5 September 2020 was conducted, incorporating data from 41 departments across 19 countries. Relevant clinical outcomes, imaging techniques, surgical approaches, and rehabilitation strategies were analyzed to identify key trends and variability in practices.

RESULTS

The review indicates that children receiving ABIs exhibit diverse auditory outcomes influenced by individual anatomical variations and developmental factors. Early implantation, particularly before the age of three, positively correlates with better auditory and language development. Multicenter experiences underscore the necessity of tailored decision-making, which considers both surgical candidacy and comprehensive rehabilitation resources.

DISCUSSION:

The variability in outcomes emphasizes the need for improved consensus and guidelines regarding eligibility, surgical techniques, and multidisciplinary rehabilitation approaches. Notable complications and the necessity for thorough imaging assessments were also identified as critical components affecting clinical decisions.

CONCLUSION

A formal consensus statement is warranted to standardize best practices in ABI management. This will not only enhance patient outcomes but also guide future research efforts to address the remaining challenges in the treatment of children with severe IEMs. Enhanced collaboration among team members will be pivotal in achieving these objectives.

Predictors of cochlear implant outcomes in pediatric auditory neuropathy: A matched case-control study

OBJECTIVES

Current evidence supports the benefits of cochlear implants (CIs) in children with hearing loss, including those with auditory neuropathy spectrum disorder (ANSD). However, there is limited evidence regarding factors that hold predictive value for intervention outcomes.

DESIGN

This retrospective case-control study consisted of 66 children with CIs, including 22 with ANSD and 44 with sensorineural hearing loss (SNHL) matched on sex, age, age at CI activation, and the length of follow-up with CIs (1:2 ratio). The case and control groups were compared in the results of five open-set speech perception tests, and a Forward Linear Regression Model was used to identify factors that can predict the post-CI outcomes.

RESULTS

There was no significant difference in average scores between the two groups across five outcome measures, ranging from 88.40% to 95.65%. The correlation matrix revealed that younger ages at hearing aid fitting and CI activation positively influenced improvements in speech perception test scores. Furthermore, among the variables incorporated in the regression model, the duration of follow-up with CIs, age at CI activation, and the utilization of two CIs demonstrated prognostic significance for improved post-CI speech perception outcomes.

CONCLUSIONS

Children with ANSD can achieve similar open-set speech perception outcomes as children with SNHL. A longer CI follow-up, a lower age at CI activation, and the use of two CIs are predictive for optimal CI outcome.

Factors that influence performance in pediatric cochlear implant recipients with cochlear nerve deficiency

OBJECTIVES

Children with cochlear nerve deficiency (CND) have wide variability in outcomes with cochlear implant (CI) use. The current study aims to report a large cohort of pediatric CI recipients with CND and to evaluate for factors that may predict improved performance.

METHODS

The current study is a retrospective review of pediatric CI recipients with CND at a tertiary academic hospital. Variables including cochlear nerve status (hypoplasia vs aplasia), age at implantation, cochleovestibular malformation, bony cochlear nerve aperture, internal auditory canal aperture, and cognitive delay were evaluated for predictors of postoperative performance. A stepwise multinomial regression analysis was performed.

RESULTS

Forty-seven CI recipients (54 ears) were included in the analysis. A majority (59%) showed auditory capabilities with their CI. Twenty percent of recipients achieved some level of open-set speech perception with their CI. The regression analysis identified cochlear nerve status and cognitive delay as predictors of performance. CI recipients with cochlear nerve hypoplasia had significantly improved performance compared to those with aplasia (p = 0.003). Recipients with cognitive delay had more limited benefit than those without cognitive delay (p = 0.033).

CONCLUSIONS

Children with CND can benefit from CI use, with outcomes spanning from non-use to development of spoken language. Predictive factors for improved performance include a lack of cognitive delay and cochlear hypoplasia rather than aplasia. These can be important considerations for parent counseling and decision making.

Single-Sided Deafness and Hearing Rehabilitation Modalities: Contralateral Routing of Signal Devices, Bone Conduction Devices, and Cochlear Implants

Single sided deafness (SSD) is characterized by significant sensorineural hearing loss, severe or profound, in only one ear. SSD adversely affects various aspects of auditory perception, including causing impairment in sound localization, difficulties with speech comprehension in noisy environments, and decreased spatial awareness, resulting in a significant decline in overall quality of life (QoL). Several treatment options are available for SSD, including cochlear implants (CI), contralateral routing of signal (CROS), and bone conduction devices (BCD). The lack of consensus on outcome domains and measurement tools complicates treatment comparisons and decision-making. This narrative overview aims to summarize the treatment options available for SSD in adult and pediatric populations, discussing their respective advantages and disadvantages. Rerouting devices (CROS and BCD) attenuate the effects of head shadow and improve sound awareness and signal-to-noise ratio in the affected ear; however, they cannot restore binaural hearing. CROS devices, being non-implantable, are the least invasive option. Cochlear implantation is the only strategy that can restore binaural hearing, delivering significant improvements in speech perception, spatial localization, tinnitus control, and overall QoL. Comprehensive preoperative counseling, including a discussion of alternative technologies, implications of no treatment, expectations, and auditory training, is critical to optimizing therapeutic outcomes.

An Umbrella Review of Cochlear Implant Outcomes in Children With Auditory Neuropathy

PURPOSE

The objective of this overview of systematic reviews (SRs; umbrella review) was to systematically summarize and critically appraise current evidence of cochlear implant (CI) outcomes in children with auditory neuropathy spectrum disorder (ANSD).

METHOD

This study was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement. The methodological quality and the risk of bias in the included SRs were assessed using A MeaSurement Tool to Assess systematic Reviews 2 checklist and the Risk of Bias in Systematic Reviews tool, respectively.

RESULTS

According to eight included SRs, children with ANSD achieve CI outcomes (speech perception performance) similar to their peers with sensorineural hearing loss. In children with postsynaptic ANSD (cochlear nerve deficiency), cochlear nerve hypoplasia is associated with better speech recognition outcomes compared with cochlear nerve aplasia, especially in the absence of additional disabilities. Except for one study, the overall quality of the included SRs was critically low, and except for three studies, evidence of a high risk of bias was identified in other included SRs.

CONCLUSIONS

Current evidence supports CI benefits for children with ANSD. To improve the quality of evidence, well-designed, prospective studies with appropriate sample sizes, using valid outcome measures, clarifying matching criteria, and taking into account the role of confounding factors are essential.

Outcome of cochlear implantation in a case of cochlear aplasia with cochlear nerve deficiency

Cochlear nerve deficiency in cochlear aplasia is a contraindication for cochlear implantation (CI) anticipating poor auditory response. Few authors have reported auditory outcomes even without nerves following CI. This study outlines the audiological outcomes of a patient in early childhood with cochlear aplasia and cochlear nerve deficiency who underwent CI. Auditory and speech-language development were assessed using the Categories of Auditory Performance (CAP) scale, Speech Intelligibility Rating (SIR) scale and Ling-6 sound test; at the time of switch-on, after 6 and 12 months of auditory verbal therapy. Significant differences across CAP, SIR and Ling-6 sound detection scores were noted, with the highest mean scores at the 12th-month postimplantation, indicating substantial improvement in auditory and speech-language skills. In cochlear aplasia cases, residual cochlear elements and nerve fibres cannot be ruled out. Our report emphasises the need for research, as this has the potential to impact the existing guidelines for CI candidacy.

Cochlear Health and Cochlear-implant Function

The cochlear implant (CI) is widely considered to be one of the most innovative and successful neuroprosthetic treatments developed to date. Although outcomes vary, CIs are able to effectively improve hearing in nearly all recipients and can substantially improve speech understanding and quality of life for patients with significant hearing loss. A wealth of research has focused on underlying factors that contribute to success with a CI, and recent evidence suggests that the overall health of the cochlea could potentially play a larger role than previously recognized. This article defines and reviews attributes of cochlear health and describes procedures to evaluate cochlear health in humans and animal models in order to examine the effects of cochlear health on performance with a CI. Lastly, we describe how future biologic approaches can be used to preserve and/or enhance cochlear health in order to maximize performance for individual CI recipients.

Audiological characteristics and cochlear implant outcome in children with cochlear nerve deficiency

Objectives

This study aimed to examine the audiological characteristics and validity of predicting outcomes of cochlear implants (CIs) in children with cochlear nerve deficiency (CND) based on the internal auditory meatus (IAM) nerve grading system.

Methods

The audiological characteristics of 188 ears in 105 children diagnosed with CND were analyzed based on the IAM nerve grading system. In addition, 42 children with CND who underwent CI were also divided into four groups based on the system, and their auditory and speech performance at baseline (preoperative) and 6, 12, and 24 months after CI were analyzed and compared with those of the control group (n = 24) with a normal cochlear nerve (CN) and CI.

Results

The audiological test results showed no significant differences among the four CND groups in terms of elicited rates of distortion product otoacoustic emission (DPOAE) (p = 1.000), auditory brainstem response (ABR) (p = 0.611), and cochlear microphonic (CM) (p = 0.167). Hearing in the CND IV group was significantly better than that in the CND I group (p < 0.05). In children with CI, the auditory and speech performance of the control group was significantly higher than all CND groups from 6 to 24 months (p < 0.05) and 12 to 24 months (p < 0.05), respectively. Meanwhile, there were no significant differences between each pair group in the four CND groups (p > 0.05).

Conclusion

Children with CND, including those in whom the CN was not visualized by MRI, can benefit from CI. Additionally, the IAM nerve grading system could not predict the outcomes of CI in children with CND.

Long-Term Auditory and Speech Outcomes of Cochlear Implantation in Children With Cochlear Nerve Aplasia

OBJECTIVES

In this study, we aimed to (1) review the long-term outcomes of cochlear implantation in children with cochlear nerve aplasia and (2) compare the development of their auditory and speech abilities to children with normal-sized cochlear nerves.

DESIGN

This is a retrospective case-control study. Patients who underwent unilateral cochlear implant (CI) surgery in a tertiary referral center from September 2012 to December 2018 were reviewed. The study group included 55 children with cochlear nerve aplasia diagnosed using preoperative images. The control group included 35 children with normal-sized cochlear nerves. The control group did not differ from the study group in terms of age at implantation, pre-implantation auditory and speech abilities, or the electrode array type. Cochlear implantation outcomes were assessed using a test battery, including the Categories of Auditory Performance (CAP) score, the Speech Intelligibility Rating (SIR) score, behavioral audiometry, and closed- or open-set speech recognition tests. The development of auditory and speech abilities was compared between the two groups using Generalized Linear Mixed-effect Models.

RESULTS

The mean duration of CI usage was 4.5 years (SD = 1.5, range = 2.0 to 9.5) in the study group. The CAP scores, SIR scores, and aided hearing thresholds improved significantly post-implantation in the study group, but were significantly poorer than those in the control group. Generalized Linear Mixed-effect Models showed that the development of CAP and SIR scores was significantly slower in the study group than in the control group. Overall, 27 (49%) children with cochlear nerve aplasia had some degree of open-set speech perception skills, but the monosyllabic and bisyllabic word recognition rates were significantly lower than those in the control group.

CONCLUSION

For children with cochlear nerve aplasia, auditory perception and speech intelligibility continued to improve in the long-term follow-up, but this progress was significantly slower than in children with normal-sized cochlear nerves. Most children with cochlear nerve aplasia could obtain the ability of common phrase perception and understanding simple spoken language with consistent CI usage and auditory rehabilitation.

Functional Outcomes of Cochlear Implantation in Children with Bilateral Cochlear Nerve Aplasia

Background and Objectives: Many otologists face a dilemma in the decision-making process of surgical management of patients with cochlear nerve (CN) aplasia. The goal of this study is to provide fresh evidence on cochlear implantation (CI) results in patients with CN aplasia. Materials and Methods: We scrutinized functional outcomes in 37 ears of 21 children with bilateral CN aplasia who underwent unilateral or bilateral CI based on cross-sectional and longitudinal assessments. Results: The Categories of Auditory Performance (CAP) scores gradually improved throughout the 3-year follow-up; however, variable outcomes existed between individuals. Specifically, 90% of recipients with a 1-year postoperative CAP score ≤1 could not achieve a CAP score over 1 even at 3-year postoperative evaluation, while the recipients with a 1-year postoperative CAP score >1 had improved auditory performance, and 72.7% of them were able to achieve a CAP score of 4 or higher. Meanwhile, intraoperative electrically evoked compound action potential was not correlated with postoperative CAP score. Conclusions: Our results further refine previous studies on the clinical feasibility of CI as the first treatment modality to elicit favorable auditory performance in children with CN aplasia. However, special attention should be paid to pediatric patients with an early postoperative CAP score ≤1 for identification of unsuccessful cochlear implants and switching to auditory brainstem implants.

Cochlear Implant Outcomes in CHARGE Syndrome: Updated Perspectives

OBJECTIVE

To evaluate outcomes of auditory implants in children with CHARGE syndrome and describe the evolution in management of hearing loss in this complex population.

METHODS

A retrospective case review was performed at a tertiary referral center. Children with CHARGE syndrome who received either a cochlear implant (CI) or auditory brainstem implant (ABI) were included. Clinical records, demographic information, CHARGE features, neuroimaging, audiology, hearing rehabilitation interventions, operative notes, and outcomes were reviewed.

RESULTS

Thirteen children with CHARGE syndrome underwent a total of 19 cochlear implants between 2008 and 2020. Among the congenitally deafened children (n = 9), six underwent bilateral implantation (five simultaneous and one sequential). Bilateral implantation was performed even in the presence of diminutive-appearing cochlear nerves. The average age of implantation was 1.1 years, and the mean device use time was 9.4 hours per day. Patients showed improvements in subjective family assessment related to hearing. In this group, two patients use oral communication, five use total communication, and two use sign language exclusively. Among the children with progressive hearing loss, the mean age of hearing deterioration was 4.4 years of age, and the device use time on average was 9.8 hours per day. The highest performer in the cohort was a child who lost hearing in their only hearing ear at age 4 and had normal cochleovestibular anatomy on that side. One child received an auditory brainstem implant at age two after deriving no benefit from a CI and can detect environmental sounds but is currently a nonuser. Over time, we noted that implantation occurred earlier in life and that practice has shifted toward bilateral implantation.

CONCLUSIONS

Compared to a previous institutional cohort, children evaluated in this study were often implanted at a younger age and bilaterally with significantly improved outcomes. A CI evaluation should be considered in children with CHARGE syndrome to maximize sensory input and auditory ability.

High-frequency Cochlear Nerve Deficit Region: Relationship With Deaf Duration and Cochlear Implantation Performance in Postlingual Deaf Adults

OBJECTIVE

To analyze the changes of cochlear nerve diameter and the presence of a cochlear nerve deficit at a high-frequency region and investigate their effects on cochlear implant (CI) performance in postlingual deaf adults.

STUDY DESIGN

Retrospective.

SETTING

Tertiary care academic center.

PATIENTS

Eighty-three postlingual deaf adults with no labyrinthine anomalies or cognitive deficits who received a CI with perimodiolar electrodes from a single manufacturer.

MAIN OUTCOMES AND MEASURES

We evaluated the changes of cochlear nerve diameter and the presence of a "tail sign," defined as identifiable nerve fibers originating from the far basal turn of the cochlea, which represents the presence of cochlear nerve at a high-frequency region in magnetic resonance imaging, on monosyllabic word recognition scores.

RESULTS

The cochlear nerve diameter showed a positive correlation with word recognition scores (maximum diameter, R2 = 0.26, p < 0.01; minimum diameter, R2 = 0.26, p < 0.01), but a negative correlation with deaf duration. Recipients with a positive tail sign performed better (73 ± 19%) than those without (45 ± 24%, p < 0.01). A positive tail sign was more commonly found in good performers (52 of 62, 84%) than in poor performers (5 of 21, 24%, p < 0.01).

CONCLUSIONS

Favorable outcomes could be anticipated in postlingual deaf adults with a large cochlear nerve diameter and positive tail sign. A presence of cochlear nerve at a high-frequency region may be an imaging marker for predicting good CI performance.

Adult Onset Bilateral Cochlear Nerve Atrophy and Cochlear Implantation: A Case Report and Review of the Literature

OBJECTIVE

To describe a case of idiopathic bilateral cochlear nerve atrophy acquired in adulthood.

PATIENT

A 75-year-old male with acquired bilateral cochlear nerve atrophy.

INTERVENTION(S)

Unilateral cochlear implantation.

MAIN OUTCOME AND RESULTS

Description of a patient with acquired bilateral cochlear nerve atrophy diagnosed at the age of 75. The patient had normal hearing and no communication deficits until the age of 66. At this point, the patient demonstrated a slight asymmetric hearing loss, which progressed to severe sensorineural hearing loss. Due to the resulting communication deficit, cochlear device implantation candidacy was pursued. Pre-operative magnetic resonance imaging (MRI) showed severe atrophy versus absence of the cochlear nerves bilaterally. After careful counseling regarding the expected communication outcomes given the MRI findings, the patient underwent left-sided cochlear implantation. The patient gained sound awareness, but no additional communication benefit compared to pre-operative baseline abilities.

CONCLUSION

Cochlear nerve deficiency is a known finding in certain cases of congenital and acquired hearing loss, but no cases of idiopathic adult-onset bilateral nerve atrophy have been reported. Without MR imaging, the clinically significant finding would not have been identified. Thus, MRI is advantageous when compared with other imaging modalities in patients with progressive sensorineural hearing loss and enables improved patient counseling regarding expected auditory and communication outcomes.

Pre- and post-operative imaging of cochlear implants: a pictorial review

Cochlear implants are increasingly used to treat sensorineural hearing disorders in both children and adults. Pre-operative computed tomography and magnetic resonance imaging play a pivotal role in patient selection, to rule out findings that preclude surgery or identify conditions which may have an impact on the surgical procedure. The post-operative position of the electrode array within the cochlea can be reliably identified using cone-beam computed tomography. Recognition of scalar dislocation, cochlear dislocation, electrode fold, and malposition of the electrode array may have important consequences for the patient such as revision surgery or adapted fitting.

Pediatric Auditory Brainstem Implant Users Compared With Cochlear Implant Users With Additional Disabilities

OBJECTIVES

To evaluate long-term language development in children with prelingual deafness who received auditory brainstem implants (ABIs) compared with children who received cochlear implants (CIs) at the same hospital. Additional non-auditory disabilities were taken into account.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

PATIENTS

Ten children with bilateral malformations of the cochlea and/or cochlear nerve who received ABIs, including seven with additional disabilities, and 147 children with CIs as a reference group, including 22 children with additional disabilities.

INTERVENTION

ABIs were implanted at 1.3 to 6.2 years of age. Follow-up ranged from 1.1 to 7.7 years.

MAIN OUTCOME MEASURES

Receptive and expressive language abilities were assessed using the Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS), the Categories of Auditory Performance (CAP), the Meaningful Use of Speech Scale (MUSS), and the Speech Intelligibility Rate (SIR).

RESULTS

Of the 10 children with ABIs, seven had long-term follow-up data. Within 1 year, six of the seven children with ABIs could identify sounds, respond to speech, and use their voice to attract attention. Language skills developed at a slower rate than in children with CIs and reached the same competence level when additional disabilities were absent. These language skills matched, on average, those of children with CIs with additional disabilities.

CONCLUSION

For deaf children with bilateral inner ear malformations, ABIs provide satisfactory auditory input. Children with ABIs are able to develop receptive and expressive language skills comparable to those of children with CIs with additional disabilities. Using this knowledge, preoperative parent counselling can be refined.

Auditory Brainstem Implants: Recent Progress and Future Perspectives

The auditory brainstem implant (ABI) was first developed nearly 40 years ago and provides auditory rehabilitation to patients who are deaf and ineligible for cochlear implant surgery due to abnormalities of the cochlea and cochlear nerve. The aims of the following review are to describe the history of the ABI and innovations leading up to the modern ABI system, as well as highlight areas of future development in implant design.