Auditory neuropathy spectrum disorder: predictive value of radiologic studies and electrophysiologic tests on cochlear implant outcomes and its radiologic classification

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.

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.

Predicting Postoperative Speech Perception and Audiometric Thresholds Using Intracochlear Electrocochleography in Cochlear Implant Recipients

OBJECTIVES

Electrocochleography (ECochG) appears to offer the most accurate prediction of post-cochlear implant hearing outcomes. This may be related to its capacity to interrogate the health of underlying cochlear tissue. The four major components of ECochG (cochlear microphonic [CM], summating potential [SP], compound action potential [CAP], and auditory nerve neurophonic [ANN]) are generated by different cochlear tissue components. Analyzing characteristics of these components can reveal the state of hair and neural cell in a cochlea. There is limited evidence on the characteristics of intracochlear (IC) ECochG recordings measured across the array postinsertion but compared with extracochlear recordings has better signal to noise ratio and spatial specificity. The present study aimed to examine the relationship between ECochG components recorded from an IC approach and postoperative speech perception or audiometric thresholds.

DESIGN

In 113 human subjects, responses to 500 Hz tone bursts were recorded at 11 IC electrodes across a 22-electrode cochlear implant array immediately following insertion. Responses to condensation and rarefaction stimuli were then subtracted from one another to emphasize the CM and added to one another to emphasize the SP, ANN, and CAP. Maximum amplitudes and extracochlear electrode locations were recorded for each of these ECochG components. These were added stepwise to a multi-factor generalized additive model to develop a best-fit model predictive model for pure-tone audiometric thresholds (PTA) and speech perception scores (speech recognition threshold [SRT] and consonant-vowel-consonant phoneme [CVC-P]) at 3- and 12-month postoperative timepoints. This best-fit model was tested against a generalized additive model using clinical factors alone (preoperative score, age, and gender) as a null model proxy.

RESULTS

ECochG-factor models were superior to clinical factor models in predicting postoperative PTA, CVC-P, and SRT outcomes at both timepoints. Clinical factor models explained a moderate amount of PTA variance ( r2 = 45.9% at 3-month, 31.8% at 12-month, both p < 0.001) and smaller variances of CVC-P and SRT ( r2 range = 6 to 13.7%, p = 0.008 to 0.113). Age was not a significant predictive factor. ECochG models explained more variance at the 12-month timepoint ( r2 for PTA = 52.9%, CVC-P = 39.6%, SRT = 36.4%) compared with the 3-month one timepoint ( r2 for PTA = 49.4%, CVC-P = 26.5%, SRT = 22.3%). The ECochG model was based on three factors: maximum SP deflection amplitude, and electrode position of CM and SP peaks. Adding neural (ANN and/or CAP) factors to the model did not improve variance explanation. Large negative SP deflection was associated with poorer outcomes and a large positive SP deflection with better postoperative outcomes. Mid-array peaks of SP and CM were both associated with poorer outcomes.

CONCLUSIONS

Postinsertion IC-ECochG recordings across the array can explain a moderate amount of postoperative speech perception and audiometric thresholds. Maximum SP deflection and its location across the array appear to have a significant predictive value which may reflect the underlying state of cochlear health.

A systematic review on the imaging findings in auditory neuropathy spectrum disorder

Purpose

The present systematic review examined imaging findings in the Auditory Neuropathy Spectrum Disorder (ANSD) population.

Methods

Electronic databases such as Pub Med, Google Scholar, J Gate, and Science Direct were used to conduct a literature search. The articles retrieved through the literature search were assessed in two stages. In the first stage, title and abstract screening were done; in the second stage, a full-length article review was done. From the 379 shortlisted records, 19 articles were chosen for the full-length review.

Results

The selected articles performed imaging using Computerized tomography (CT) and magnetic resonance imaging (MRI). In most studies, cochlear nerve deficiency (CND) was the most prevalent anomaly in the ANSD group. Also, MRI was the imaging modality of choice recommended in most studies. It was also noted that CND was a characteristic feature of unilateral ANSD.

Conclusion

From this systematic review, it is clear that integrating imaging studies into diagnostic protocol would help to understand the underlying pathology better and expedite decision-making and intervention for ANSD patients.

Nomogram for prediction of hearing rehabilitation outcome in children with congenital sensorineural hearing loss after cochlear implantation

Background

Reliable predictors for rehabilitation outcomes in patients with congenital sensorineural hearing loss (CSNHL) after cochlear implantation (CI) are lacking. The purchase of this study was to develop a nomogram based on clinical characteristics and neuroimaging features to predict the outcome in children with CSNHL after CI.

Methods

Children with CSNHL prior to CI surgery and children with normal hearing were enrolled into the study. Clinical data, high resolution computed tomography (HRCT) for ototemporal bone, conventional brain MRI for structural analysis and brain resting-state fMRI (rs-fMRI) for the power spectrum assessment were assessed. A nomogram combining both clinical and imaging data was constructed using multivariate logistic regression analysis. Model performance was evaluated and validated using bootstrap resampling.

Results

The final cohort consisted of 72 children with CSNHL (41 children with poor outcome and 31 children with good outcome) and 32 healthy controls. The white matter lesion from structural assessment and six power spectrum parameters from rs-fMRI, including Power4, Power13, Power14, Power19, Power23 and Power25 were used to build the nomogram. The area under the receiver operating characteristic (ROC) curve of the nomogram obtained using the bootstrapping method was 0.812 (95 % CI = 0.772-0.836). The calibration curve showed no statistical difference between the predicted value and the actual value, indicating a robust performance of the nomogram. The clinical decision analysis curve showed a high clinical value of this model.

Conclusions

The nomogram constructed with clinical data, and neuroimaging features encompassing ototemporal bone measurements, white matter lesion values from structural brain MRI and power spectrum data from rs-fMRI showed a robust performance in predicting outcome of hearing rehabilitation in children with CSNHL after CI.

Cochlear implantation in children with auditory neuropathy spectrum disorder: an updated systematic review

BACKGROUND

The goal of managing auditory neuropathy spectrum disorder (ANSD) is to restore the children's ability to discriminate auditory information. Children who are not making sufficient progress in speech comprehension, and speech and language development after receiving adequate auditory re/habilitation and/or acoustic amplification may be candidates for cochlear implantation (CI). Despite the growing number of published literature on CI outcomes in children with ANSD, the current evidence is primarily based on case reports or retrospective chart reviews some of which had a limited number of children. In addition, the outcomes of CI seem to vary between children with ANSD. Thus, compelling evidence is lacking. This updated systematic review evaluated the speech perception, language, and speech intelligibility outcomes of children with ANSD post-CI.

METHODS

An online bibliographic search was conducted in PubMed, Scopus, Web of Science, and CENTRAL databases. We included both interventional and observational studies that assessed the outcomes of the CI in  children with ANSD.

RESULTS

Thirty-three studies were included in this systematic review. Several tests were used to assess speech perception following CI in children with ANSD. The findings of this study revealed that  children with ANSD had mean Categories of Auditory Performance scores ranging from 4.3 to 7 post-operatively, this result was better than the pre-operative scores which ranged between 0.4 to 2.5. Likewise, the Infant-Toddler Meaningful Auditory Integration Scale, Phonetically Balanced Kindergarten, and multisyllabic lexical neighborhood test showed clinically relevant improvement after CI. The same findings were reported for language and speech intelligibility scores. One study investigated the quality of life/children satisfaction after CI and showed overall good satisfaction with the outcomes.

CONCLUSIONS

The present systematic review suggests that CI is a feasible and effective hearing  rehabilitation modality for children with ANSD.

REGISTRATION AND PROTOCOL

PROSPERO ID: CRD42021279140.

Indicators for cochlear implantation in children with auditory neuropathy spectrum disorder: A systematic review

PURPOSE

ANSD refers to a group of auditory diseases demonstrating intact outer hair cells and desynchronized neural firings of the auditory nerve. A cochlear implant is a promising intervention strategy for severe to profound sensorineural hearing loss (SNHL). However, due to its variable outcomes in children with ANSD, a consensus has yet to be reached on its performance. This study aimed to review the literature to determine the efficacy of cochlear implants in children with ANSD and to determine prognostic indicators. The study identifies the pre-operative and post-operative predictors of success for CI in children with ANSD.

METHOD

The review was carried out using PRISMA guidelines. This resulted in 9630 topic-related articles. Among these, 17 articles met the inclusion and exclusion criteria that were included for the study. The quality and potential risks associated with each article were evaluated using the quality impact assessment protocol (QUIPS) tool.

RESULTS

A review of 17 articles was conducted to highlight these predictors. Most selected studies included case reports, case series, cohorts, and comparisons between children with ANSD and SNHL. Assessment of study quality reported an overall low risk of bias. The overall result showed cochlear implant would be an effective option for children with ANSD. However, there are specific prognostic indicators about which clinician needs to be aware before recommending CI for children with ANSD. Our review study identified a set of pre-operative and post-operative indicators that predicted speech and auditory performance and gave some insight into the lesion site in ANSD individuals.

CONCLUSION

This review concludes CI is an effective option for children with ANSD. However, before recommending CI, a detailed assessment is required from different perspectives, which could serve as predictors of postoperative outcomes. This review highlights the need to include more precise tools, such as genetic testing to describe the lesion site to choose the most appropriate management strategy for children with ANSD. Knowledge about the prognostic indicators and the effective assessment protocols would help clinicians for the better candidacy selection.

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.

Systematic Literature Review and Early Benefit of Cochlear Implantation in Two Pediatric Auditory Neuropathy Cases

Approximately 1 in 10 children with hearing loss is affected by auditory neuropathy spectrum disorder (ANSD). People who have ANSD usually have great difficulty understanding speech or communicating. However, it is possible for these patients to have audiograms that may indicate profound hearing loss up to normal hearing. This disorder is prognosed with positive, intact or present otoacoustic emissions (OAE) and/or cochlear microphonics (CM) as well as abnormal or absent auditory brainstem responses (ABR). Treatment methods include conventional hearing aids as well as cochlear implants. Cochlear implants (CI) usually promise better speech understanding for ANSD patients. We performed a systematic literature review aiming to show what improvements can effectively be achieved with cochlear implants in children with ANSD and compare this with our experience with two cases of ANSD implanted at our clinic. The retrospective review of two young CI patients diagnosed with ANSD during infancy demonstrated improvements over time in speech development communicated by their parents.

Genetic etiological analysis of auditory neuropathy spectrum disorder by next-generation sequencing

Objective

Auditory neuropathy spectrum disease (ANSD) is caused by both environmental and genetic causes and is defined by a failure in peripheral auditory neural transmission but normal outer hair cells function. To date, 13 genes identified as potentially causing ANSD have been documented. To study the etiology of ANSD, we collected 9 probands with ANSD diagnosed in the clinic and performed targeted next-generation sequencing.

Methods

Nine probands have been identified as ANSD based on the results of the ABR tests and DPOAE/CMs. Genomic DNA extracted from their peripheral blood was examined by next-generation sequencing (NGS) for a gene panel to identify any potential causal variations. For candidate pathogenic genes, we performed co-segregation among all family members of the pedigrees. Subsequently, using a mini-gene assay, we examined the function of a novel splice site mutant of OTOF.

Results

We analyzed nine cases of patients with ANSD with normal CMs/DPOAE and abnormal ABR, discovered three novel mutants of the OTOF gene that are known to cause ANSD, and six cases of other gene mutations including TBC1D24, LARS2, TIMM8A, MITF, and WFS1.

Conclusion

Our results extend the mutation spectrum of the OTOF gene and indicate that the genetic etiology of ANSD may be related to gene mutations of TBC1D24, LARS2, TIMM8A, MITF, and WFS1.

Task force Guideline of Brazilian Society of Otology - hearing loss in children - Part II - Treatment

OBJECTIVES

To provide an overview of the main evidence-based recommendations for the diagnosis of hearing loss in children and adolescents aged 0-18 years.

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 childhood hearing loss 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) treatment of sensorineural hearing loss: individual hearing aids, bilateral cochlear implants, cochlear implants in young children, unilateral hearing loss, and auditory neuropathy spectrum disorder; and (2) treatment of conductive/mixed hearing loss: external/middle ear malformations, ventilation tube insertion, and tympanoplasty in children.

CONCLUSIONS

In children with hearing loss, in addition to speech therapy, Hearing AIDS (HAs) or implantable systems may be indicated. Even in children with profound hearing loss, both the use of HAs and behavioral assessments while using the device are important.

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.

Effect of inner ear malformations on intraoperative ECAP thresholds and postoperative auditory performance

Objectives

This study sought to characterize the influence of inner ear malformations (IEMs) on intraoperative electrically evoked compound action potential (ECAP) and auditory performance to better understand the underlying pathophysiology related to variabilities in cochlear implant (CI) outcomes that individuals with malformed cochlea may present.

Methods

The medical records of 222 ears implanted with Cochlear Nucleus CI were reviewed. Of the total, 64 ears had radiologic evidence of IEMs, and 158 ears were normal. Individuals with IEMs were grouped based on the severity of anomalies; 38 had mild IEMs (e.g., enlarged vestibular aqueduct, incomplete partition type II, etc.) and 26 had severe IEMs (e.g., cochlear nerve hypoplasia, common cavity, etc.). Intraoperative ECAP thresholds obtained via neural response telemetry (NRT) and the categories of auditory performance (CAP) scores measured at 12 months postoperative were compared and correlated.

Results

Absent ECAP responses were more apparent in the IEM group. ECAP thresholds were significantly elevated in the severe IEM group, while the mild IEM group had ECAP thresholds comparable to the normal group. The mild IEM group achieved CAP scores similar to the normal control. Patients in the severe IEM group showed significantly lower CAP scores at 12 months postoperative. Significant negative relationships existed between ECAP thresholds and CAP scores obtained from all subjects.

Conclusion

Measurable ECAP responses and NRT thresholds varied across groups. The inverse relationship between NRT thresholds and CAP scores may suggest that electrophysiological responses measured during surgery may potentially be indicative of postoperative performance in our CI population.

Level of Evidence

2b.

Amplitude Growth Functions of Auditory Nerve Responses to Electric Pulse Stimulation With Varied Interphase Gaps in Cochlear Implant Users With Ipsilateral Residual Hearing

Amplitude growth functions (AGFs) of electrically evoked compound action potentials (eCAPs) with varying interphase gaps (IPGs) were measured in cochlear implant users with ipsilateral residual hearing (electric-acoustic stimulation [EAS]). It was hypothesized that IPG effects on AGFs provide an objective measure to estimate neural health. This hypothesis was tested in EAS users, as residual low-frequency hearing might imply survival of hair cells and hence better neural health in apical compared to basal cochlear regions. A total of 16 MED-EL EAS subjects participated, as well as a control group of 16 deaf cochlear implant users. The IPG effect on the AGF characteristics of slope, threshold, dynamic range, and stimulus level at 50% maximum eCAP amplitude (level_50%) was investigated. AGF threshold and level_50% were significantly affected by the IPG in both EAS and control group. The magnitude of AGF characteristics correlated with electrode impedance and electrode-modiolus distance (EMD) in both groups. In contrast, the change of the AGF characteristics with increasing IPG was independent of these electrode-specific measures. The IPG effect on the AGF level_50% in both groups, as well as on the threshold in EAS users, correlated with the duration of hearing loss, which is a predictor of neural health. In EAS users, a significantly different IPG effect on level_50% was found between apical and medial electrodes. This outcome is consistent with our hypothesis that the influence of IPG effects on AGF characteristics provides a sensitive measurement and may indicate better neural health in the apex compared to the medial cochlear region in EAS users.

Long-term treatment outcomes in children with auditory neuropathy spectrum disorder (ANSD)

INTRODUCTION

The present article shows long-term results in the hearing and speech development of children with auditory neuropathy spectrum disorder (ANSD). Some children were followed up for nearly 20 years, monitoring their progress through childhood into adulthood.

METHODS

This retrospective study examined data from 10 children who were diagnosed and treated at our tertiary referral center. All children were provided with hearing aids and/or cochlear implants. The children's hearing and speech development and their social and educational development were evaluated.

RESULTS

Seven children were provided with cochlear implants on both sides; three children, one of which had single-sided deafness, received hearing aids. All children with cochlear implants on both sides used their devices full-time. Speech perception ranged between 100% and 0% on one side. Five children attended a school for the hearing impaired; four children attended a regular school. Four children attended vocational training.

CONCLUSIONS

At present, there is a lack of literature on the long-term outcomes of treatment in children with ANSD. The data presented show that the hearing and speech development in children with ANSD are significantly heterogeneous. Regular school education and social integration of children with ANSD can be achieved with intensive and supportive rehabilitative methods.

Cochlear Implant Performance in Adult Patients with Absent Intraoperative Electrically Evoked Compound Action Potentials

OBJECTIVE

To describe cochlear implant performance outcomes in adult patients in whom no intraoperative electrically evoked compound action potential (ECAP) responses were able to be obtained despite intracochlear electrode placement.

STUDY DESIGN

Retrospective case review.

SETTING

Academic tertiary center.

SUBJECTS AND METHODS

Patients 18 years of age and older undergoing cochlear implantation between May 2010 and September 2018 with absent ECAP measurements intraoperatively with intracochlear electrode positioning were identified. Patient performance on sentence recognition testing using the Hearing in Noise Test (HINT) and AzBio at 6 to 12 months postoperatively was compared to preimplantation scores. Additional collected data included patient demographics, etiology of hearing loss, and preoperative pure-tone average (PTA) and word recognition scores (WRSs).

RESULTS

Intraoperative ECAP measurements were unable to be obtained in 15 cochlear implants performed on 14 patients out of 383 cochlear implant cases. Of the patients with absent ECAP measures, the mean ± SD age was 61.7 ± 15.7 years. Causes of hearing loss included congenital hearing loss, meningitis, autoimmune inner ear disease, otosclerosis, presbycusis, and Ménière's disease. The average preoperative PTA was 103.5 ± 17.0 dB. Twelve implanted ears had a WRS of 0% and 9 had a HINT score of 0% prior to surgery. The mean HINT score at 6 to 12 months postimplantation was 57.8% ± 37.8% and had improved by 42.6% ± 35.6% compared to the mean preimplantation HINT score (95% confidence interval, 22.0%-63.1%, P = .001, paired Student t test).

CONCLUSION

There is a wide range of cochlear implant performance in patients with absent intraoperative ECAP measures ranging from sound awareness to HINT scores of 100%.

Evaluation and therapy outcome in children with auditory neuropathy spectrum disorder (ANSD)

OBJECTIVES

The aims of the present study are to: describe diagnostic findings in patients with auditory neuropathy spectrum disorder (ANSD); and demonstrate the outcomes of different therapies like hearing aids (HAs) or cochlear implantation.

METHODS

32 children were diagnosed and treated at our tertiary referral center and provided with HAs or cochlear implants (CIs). All of them underwent free-field or pure-tone audiometry. Additionally, otoacoustic emissions (OAEs), impedance measurements, auditory brainstem responses (ABRs), auditory steady-state responses (ASSR), electrocochleography, and cranial magnetic resonance imaging (cMRI) were all performed. Some patients also underwent genetic evaluation. Following suitable provision pediatric audiological tests, psychological developmental diagnostic and speech and language assessments were carried out at regular intervals in all the children.

RESULTS

OAEs could initially be recorded in most of the children; 17 had no ABRs. The other eight children had a poor ABR morphology. Most of the children had typical, long-oscillating cochlear microphonics (CMs) in their ABRs, which was also observed in all of those who underwent electrocochleography. Eight children were provided with a HA and 17 received a CI. The functional gain was between 32 and 65 decibel (dB) with HAs and between 32 and 50 dB with CI. A speech discrimination level between 35 and 100% was achieved during open-set monosyllabic word tests in quiet with HA or CI. With the Hochmair-Schulz-Moser (HSM) sentence test at 65 dB SPL (sound pressure level), 75% of the children with a CI achieved a speech discrimination in noise score of at least 60% at a signal to noise ratio (SNR) of 5, and four scored 80% or higher. Most of the children (72%) were full-time users of their devices. All the children with a CI used it on a regular basis.

CONCLUSION

Only a few case reports are available in the literature regarding the long-term outcomes of ANSD therapy. The present study reveals satisfactory outcomes with respect to hearing and speech discrimination in children with CIs or HAs. The nearly permanent use of the devices reflects a subjective benefit for the children. Provision with a suitable hearing device depends on audiological results, the speech and language development of an individual child, and any accompanying disorders. Repeated audiological evaluations, interdisciplinary diagnostics, and intensive hearing and speech therapy are essential for adequate rehabilitation of this group of children.

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

OBJECTIVE

To answer the dilemma clinician's face when deciding between cochlear implant (CI) and auditory brainstem implant (ABI) treatment options in patients with cochlear nerve deficiency (CND).

STUDY DESIGN

Case study supplemented with literature review and meta-analysis.

SETTING

Tertiary referral center.

PATIENT(S)

Child with CHARGE syndrome and congenital deafness.

INTERVENTION(S)

ABI as there was no benefit after bilateral cochlear implantation.

MAIN OUTCOME MEASURES

Speech and language development, quality of life.

RESULTS

In one ear the cochleovestibular nerve was present on magnetic resonance imaging (MRI) without preoperative ABR responses. In the contra lateral ear the nerve could not be identified, despite present ABR responses. Nevertheless, there was no positive outcome with CI. The patient had improved speech and language and quality of life with ABI. Of the 108 patients with CND and CI identified in the literature review, 25% attained open-set speech perception, 34% attained closed-set speech perception, and 41% detected sounds or less. The appearance of the cochlear nerve on MRI was a useful predictor of success, with cochlear nerve aplasia on MRI associated with a smaller chance of a positive outcome post cochlear implantation compared with patients with cochlear nerve hypoplasia.

CONCLUSION

Although patients with (apparent) cochlear nerve aplasia are less likely to benefit from CI, CI before ABI is supported as some patients attain closed or open-set levels of speech perception after cochlear implantation.

International consensus (ICON) on audiological assessment of hearing loss in children

The prevalence of hearing loss in newborns and infants is estimated between 1 to 3.47 cases per 1000 live births. Early diagnosis and rehabilitation of congenital hearing loss are mandatory in order to achieve a satisfactory linguistic and cognitive development. Without appropriate opportunities to learn language, these children will fall behind their normal hearing peers in communication, cognition, reading and socio-emotional development. After promising results, neonatal screening for hearing loss and audiological evaluation are becoming more extensively carried out. In planning universal neonatal hearing screening programs, transient evoked otoacoustic emissions and auditory brainstem responses are the gold standard for the screening and diagnosis program. However, there is no consensus regarding the use of audiometry and other electrophysiological tests (such as auditory steady-state responses) in current practices. Several screening and audiological assessment procedures have been described and advocated all around the world. But, a systematic scheme of performing diagnosis in the pediatric audiology population is lacking. A consensus conference was held at the International Federation of Oto-rhino-laryngological Societies Congress, in June 2017, to discuss the different current practices and to identify the best neonatal hearing screening and audiological assessment management. This article is intended to provide professionals with recommendations about the "best practice" based on consensus opinion of the session's speakers, and a review of the literature on the efficacy of various assessment options for children with hearing loss.

Cochlear Implant Outcomes in Cochlea Nerve Aplasia and Hypoplasia

OBJECTIVE

To assess cochlear implant (CI) outcomes, and factors affecting outcomes, for children with aplasia/ hypoplasia of the cochlea nerve. We also developed a new grading system for the nerves of the internal auditory meatus (IAM) and cochlea nerve classification.

STUDY DESIGN

Retrospective patient review.

SETTING

Tertiary referral hospital and cochlear implant program.

PATIENTS

Children 0 to 16 years inclusive with a CI who had absent/hypoplastic cochlea nerve on magnetic resonance imaging (MRI).

INTERVENTION

Cochlear implant.

MAIN OUTCOME MEASURES

MRI, trans-tympanic electrical auditory brainstem response, intraoperative electrical auditory brainstem response, Neural Response Telemetry, Categories of Auditory Perception score, Main mode of communication.

RESULTS

Fifty CI recipients (26 males and 24 females) were identified, 21 had bilateral CIs, 27 had developmental delay. MRI showed cochlea nerve aplasia in 64 ears, hypoplasia in 25 ears, and a normal nerve in 11 ears. Main mode of communication was analyzed for 41 children: 21 (51%) used verbal language (15 speech alone, 5 speech plus some sign, 1 bilingual in speech and sign), and 20 (49%) used sign language (10 sign alone, 9 sign plus some speech, 1 tactile sign). Seventy-three percent of children used some verbal language. Cochlea nerve aplasia/ hypoplasia and developmental delay were both significant factors affecting main mode of communication. Categories of Auditory Performance scores were available for 59 CI ears; 47% with CN Aplasia (IAM nerve grades 0-III) and 89% with CN hypoplasia (IAM nerve grade IV) achieved Categories of Auditory Performance scores of 5 to 7 (some verbal understanding) (p = 0.003).

CONCLUSION

Our results are encouraging and useful when counselling families regarding the likelihood of language outcomes and auditory understanding.

Systematic review of compound action potentials as predictors for cochlear implant performance

OBJECTIVES/HYPOTHESIS

The variability in speech perception between cochlear implant users is thought to result from the degeneration of the auditory nerve. Degeneration of the auditory nerve, histologically assessed, correlates with electrophysiologically acquired measures, such as electrically evoked compound action potentials (eCAPs) in experimental animals. To predict degeneration of the auditory nerve in humans, where histology is impossible, this paper reviews the correlation between speech perception and eCAP recordings in cochlear implant patients.

DATA SOURCES

PubMed and Embase.

REVIEW METHODS

We performed a systematic search for articles containing the following major themes: cochlear implants, evoked potentials, and speech perception. Two investigators independently conducted title-abstract screening, full-text screening, and critical appraisal. Data were extracted from the remaining articles.

RESULTS

Twenty-five of 1,429 identified articles described a correlation between speech perception and eCAP attributes. Due to study heterogeneity, a meta-analysis was not feasible, and studies were descriptively analyzed. Several studies investigating presence of the eCAP, recovery time constant, slope of the amplitude growth function, and spatial selectivity showed significant correlations with speech perception. In contrast, neural adaptation, eCAP threshold, and change with varying interphase gap did not significantly correlate with speech perception in any of the identified studies.

CONCLUSIONS

Significant correlations between speech perception and parameters obtained through eCAP recordings have been documented in literature; however, reporting was ambiguous. There is insufficient evidence for eCAPs as a predictive factor for speech perception. More research is needed to further investigate this relation. Laryngoscope, 2016 127:476-487, 2017.

Evaluation of cochlear nerve diameter and cross-sectional area in ANSD patients by 3.0-Tesla MRI

CONCLUSIONS

The size of cochlear nerve (CN) is atrophic in adult auditory neuropathy spectrum disorder (ANSD) patients compared with non-ANSD sensorineural hearing loss (SNHL) patients and normal hearing subjects, and CN deficiency is one of the lesions for ANSD patients.

OBJECTIVES

To evaluate the dimensions of CN in adult ANSD patients on magnetic resonance imaging (MRI) and confirm the hypothesis that CN deficiency is one of the lesions for ANSD patients.

METHODS

Medical records and MRI of 24 adult ANSD patients reviewed retrospectively and 20 non-ANSD SNHL and 24 volunteers with normal hearing were recruited as control groups. The long diameter (LD), short diameter (SD), and cross-sectional area (CSA) of CN and facial nerve (FN) were measured.

RESULTS

Among the 24 ANSD patients, this study was able to reconstruct and measure the CN of 91.7% (22/24, total 43 ears) of patients and FN of 83.3% (20/24, total 38 ears) of patients. The mean values and standard deviations of LD, SD, and CSA of CN in ANSD patients were 0.65 ± 0.20 mm, 0.44 ± 0.15 mm, and 0.30 ± 0.19 mm(2), respectively. They were significantly smaller in ANSD patients than in control groups (p < 0.001).

The auditory characteristics of children with inner auditory canal stenosis

Conclusions This study shows that the prevalence of auditory neuropathy spectrum disorder (ANSD) in the children with inner auditory canal (IAC) stenosis is much higher than those without IAC stenosis, regardless of whether they have other inner ear anomalies. In addition, the auditory characteristics of ANSD with IAC stenosis are significantly different from those of ANSD without any middle and inner ear malformations. Objectives To describe the auditory characteristics in children with IAC stenosis as well as to examine whether the narrow inner auditory canal is associated with ANSD. Method A total of 21 children, with inner auditory canal stenosis, participated in this study. A series of auditory tests were measured. Meanwhile, a comparative study was conducted on the auditory characteristics of ANSD, based on whether the children were associated with isolated IAC stenosis. Results Wave V in the ABR was not observed in all the patients, while cochlear microphonic (CM) response was detected in 81.1% ears with stenotic IAC. Sixteen of 19 (84.2%) ears with isolated IAC stenosis had CM response present on auditory brainstem responses (ABR) waveforms. There was no significant difference in ANSD characteristics between the children with and without isolated IAC stenosis.

Refinement of Molecular Diagnostic Protocol of Auditory Neuropathy Spectrum Disorder: Disclosure of Significant Level of Etiologic Homogeneity in Koreans and Its Clinical Implications

Auditory neuropathy spectrum disorder (ANSD) is a sensorineural hearing disorder caused by dysfunction of auditory neural conduction. ANSD has a heterogeneous etiology, including genetic factors; the response to cochlear implantation significantly varies depending on the etiology. The results of timely cochlear implantation for OTOF-related ANSD (DFNB9) have been reported to be good. Therefore, identifying the causative gene of ANSD, especially OTOF, is an important issue to rehabilitate these patients.Six sporadic ANSD subjects without anatomical abnormality of the cochlear nerve, including the 4 subjects that were previously reported to be without detectable OTOF mutation, were included. We performed targeted resequencing (TRS) of known deafness genes and multiphasic bioinformatics analyses of the data that ensured detection of capture failure and structural variations. Exclusion of SNP was also double checked. The TRS data previously obtained from 2 subjects were reanalyzed. Through this study, we detected 2 mutant alleles of OTOF from 5 (83.3%) of 6 ANSD subjects. All of the 5 subjects carried at least 1 mutant allele carrying p.R1939Q. This variant was categorized as a simple SNP (rs201326023) in the database and it resided in the exon with frequent capture failures, which previously led to exclusion of this variant from eligible candidacy mistakenly. In addition, we detected a structural variation within OTOF from a previously undiagnosed ANSD subject, which was the second structural variation reported in DFNB9 subjects to date.We identify a strong etiologic homogeneity of prelingual ANSD in case of the anatomically normal cochlear nerve in Koreans and now report DFNB9 as the single overwhelming cause. Multiphasic analysis of TRS data ensuring detection of capture failure and structural variations would be expected to reveal DFNB9 from a substantial portion of previously undiagnosed ANSD subjects in Koreans. Based on our results, we propose a novel strategy that incorporates imaging studies, prevalent mutation screening and multiphasic analysis of TRS data in a stepwise manner to correctly detect DFNB9 in Koreans.

Pathophysiological mechanisms and functional hearing consequences of auditory neuropathy

The effects of inner ear abnormality on audibility have been explored since the early 20th century when sound detection measures were first used to define and quantify 'hearing loss'. The development in the 1970s of objective measures of cochlear hair cell function (cochlear microphonics, otoacoustic emissions, summating potentials) and auditory nerve/brainstem activity (auditory brainstem responses) have made it possible to distinguish both synaptic and auditory nerve disorders from sensory receptor loss. This distinction is critically important when considering aetiology and management. In this review we address the clinical and pathophysiological features of auditory neuropathy that distinguish site(s) of dysfunction. We describe the diagnostic criteria for: (i) presynaptic disorders affecting inner hair cells and ribbon synapses; (ii) postsynaptic disorders affecting unmyelinated auditory nerve dendrites; (iii) postsynaptic disorders affecting auditory ganglion cells and their myelinated axons and dendrites; and (iv) central neural pathway disorders affecting the auditory brainstem. We review data and principles to identify treatment options for affected patients and explore their benefits as a function of site of lesion.

Performance of hearing skills in children with auditory neuropathy spectrum disorder using cochlear implant: a systematic review

Introduction

Currently, there are no doubts about the benefits of cochlear implants for the development of children with severe or profound hearing loss. However, there is still no consensus among researchers and professionals regarding the benefits for the improvement of hearing skills in children with auditory neuropathy spectrum disorder using cochlear implants.

Objective

Review the available evidence in the literature to answer the following: “What is the performance of hearing skills in children with auditory neuropathy spectrum disorder using cochlear implants?”

Methods

Systematic review of the literature through electronic database consultation, considering publications in the period 2002–2013.

Results

Twenty-two studies met the criteria and were included in the systematic review.

Conclusion

The analyzed studies demonstrated that after cochlear implant surgery, individuals with auditory neuropathy spectrum disorder improved their performance of hearing skills and had similar performance to that of children with sensorineural hearing loss using cochlear implant.

Unilateral auditory neuropathy spectrum disorder: retrocochlear lesion in disguise?

Objective:

To investigate whether the aetiology for hearing impairment in neonates with unilateral auditory neuropathy spectrum disorder could be explained by structural abnormalities such as cochlear nerve aplasia, a cerebellopontine angle tumour or another identifiable lesion.

Methods:

In this prospective case series, 17 neonates were diagnosed with unilateral auditory neuropathy spectrum disorder on electrophysiological testing. Diagnostic audiology testing, including auditory brainstem response testing, was supplemented with computed tomography and/or magnetic resonance imaging.

Results:

Ten of the neonates (59 per cent) showed evidence for cochlear nerve aplasia. Of the remaining seven, four were shown to have another abnormality of the temporal bone on imaging. Only three neonates (18 per cent) were not diagnosed with cochlear nerve aplasia or another lesion. Three computed tomography scans were reported as normal, but subsequent magnetic resonance imaging revealed cochlear nerve aplasia.

Conclusion:

Auditory neuropathy spectrum disorder as a unilateral condition mandates further investigation for a definitive diagnosis. This series demonstrates that most neonates with unilateral auditory neuropathy spectrum disorder had pathology as visualised on computed tomography and/or magnetic resonance imaging scans. Magnetic resonance imaging is an appropriate first-line imaging modality.