Impact of the presence of auditory neuropathy spectrum disorder (ANSD) on outcomes of children at three years of age

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.

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.

Preparing for Otoferlin gene therapy trials: A survey of NHS Paediatric Audiology and Cochlear Implant services on diagnosis and management of Auditory Neuropathy Spectrum Disorder

OBJECTIVES

Gene therapy for monogenic hearing loss is on the horizon. The first trials in patients with Auditory Neuropathy Spectrum Disorder (ANSD) due to pathogenic variants in the Otoferlin (OTOF) gene will open this year. In the UK, the new NHS Genomic Medicine Service (GMS) offers genetic testing in each child diagnosed with congenital or early onset sensorineural hearing loss. This survey study aims to map preexisting clinical pathways for the diagnosis and management of children with ANSD and identify opportunities for improvement in early identification of OTOF- related ANSD.

METHODS

A Google form with 24 questions in English covering the ANSD clinical pathway was developed with clinicians involved in the diagnosis and management ANSD. The survey was disseminated via email to all Lead clinicians of NHS Tertiary Paediatric Audiology and Cochlear Implant Services within the UK.

RESULTS

Data was received from 27 (34 %) NHS Tertiary Paediatric Audiology Services and 8 (n = 57 %) Paediatric Cochlear Implant Services. Services follow existing national guidance and provide multidisciplinary care with structured patient pathways for referral, diagnosis, and management of children with ANSD and multidisciplinary input throughout. Clinicians are aware of the genetic causes of ANSD and new processes for genetic testing, but do not uniformly refer children with ANSD for testing for OTOF pathogenic variants. As such, they had difficulty estimating numbers of children with OTOF pathogenic variants under their care.

CONCLUSION

Those results highlight the urgency of implementing hearing gene panel sequencing for all children with ANSD to provide opportunities for early diagnosis and candidacy for OTOF gene therapy trials.

NADH improves AIF dimerization and inhibits apoptosis in iPSCs-derived neurons from patients with auditory neuropathy spectrum disorder

Auditory neuropathy spectrum disorder (ANSD) is a hearing impairment involving disruptions to inner hair cells (IHCs), ribbon synapses, spiral ganglion neurons (SGNs), and/or the auditory nerve itself. The outcomes of cochlear implants (CI) for ANSD are variable and dependent on the location of lesion sites. Discovering a potential therapeutic agent for ANSD remains an urgent requirement. Here, 293T stable transfection cell lines and patient induced pluripotent stem cells (iPSCs)-derived auditory neurons carrying the apoptosis inducing factor (AIF) p.R422Q variant were used to pursue a therapeutic regent for ANSD. Nicotinamide adenine dinucleotide (NADH) is a main electron donor in the electron transport chain (ETC). In 293T stable transfection cells with the p.R422Q variant, NADH treatment improved AIF dimerization, rescued mitochondrial dysfunctions, and decreased cell apoptosis. The effects of NADH were further confirmed in patient iPSCs-derived neurons. The relative level of AIF dimers was increased to 150.7 % (P = 0.026) from 59.2 % in patient-neurons upon NADH treatment. Such increased AIF dimerization promoted the mitochondrial import of coiled-coil-helix-coiled-coil-helix domain-containing protein 4 (CHCHD4), which further restored mitochondrial functions. Similarly, the content of mitochondrial calcium (mCa2+) was downregulated from 136.7 % to 102.3 % (P = 0.0024) in patient-neurons upon NADH treatment. Such decreased mCa2+ levels inhibited calpain activity, ultimately reducing the percentage of apoptotic cells from 30.5 % to 21.1 % (P = 0.021). We also compared the therapeutic effects of gene correction and NADH treatment on hereditary ANSD. NADH treatment had comparable restorative effects on functions of ANSD patient-specific cells to that of gene correction. Our findings offer evidence of the molecular mechanisms of ANSD and introduce NADH as a potential therapeutic agent for ANSD therapy.

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.

A 15-year Review of 260 Children With Auditory Neuropathy Spectrum Disorder: II. Management and Outcomes

OBJECTIVES

Following a review of the demographic and clinical characteristics of all pediatric patients diagnosed with auditory neuropathy spectrum disorder (ANSD) by a pediatric health care system from 2005 to 2020, the present report highlights the type and timing of intervention and outcomes in the same 260 patients with ANSD.

DESIGN

This was a retrospective study reviewing the demographic data, medical history, imaging studies, audiological and speech language data, type of audiological intervention (hearing aids or cochlear implants), and mode of communication in 260 pediatric patients diagnosed with ANSD over a 15-year period.

RESULTS

A significant decrease over time in the age at hearing aid fitting was observed. While a similar reduction in the age at implantation occurred over time, cochlear implantation is still rarely performed by 12 months of age in most ANSD patients. Among bilateral ANSD patients fitted with hearing aids, the majority (89.2%) did not benefit from conventional amplification and most received cochlear implants. Some hearing aid benefit for speech and language development was observed in 5.8%, though communication difficulties were persistent and most used a combination of oral and sign language for communication. Only six patients (5%) received significant benefit from their hearing aids for speech and language development.

CONCLUSIONS

This review of ANSD management over a 15-year period reveals that hearing aids are not a viable option to develop speech and language for most infants and children with ANSD. This finding confirms previous reports and suggest that while hearing aid trials are warranted, children must be tracked closely so as to avoid delays in decision making. Cochlear implantation constitutes the major (if not only) rehabilitative intervention that allows for speech perception in patients who do not benefit from conventional amplification.

Language and health-related quality of life outcomes of children early-detected with unilateral and mild bilateral hearing loss

Introduction

We aimed to describe the language and health-related quality of life (HRQoL) outcomes of children early-identified with unilateral or mild bilateral permanent hearing loss. This was a cross-sectional community-based study of children with mild bilateral or unilateral permanent hearing loss (including unilateral auditory neuropathy spectrum disorder (ANSD)), drawn from a population-based databank in Victoria, Australia.

Methods

Enrolment in this databank is independent of early intervention and amplification approaches. Language and caregiver-reported HRQoL outcomes are described by type and degree of loss at three timepoints across child development: at age 2 years (n = 255), 5-7 years (n = 173) and 9-12 years (n = 45).

Results

Across all age groups, average language outcomes were poorer than population normative scores by between a half to two thirds of a standard deviation. Children with mild bilateral hearing loss demonstrated poorer average language outcomes than children with unilateral hearing loss, particularly at younger ages. Children with unilateral ANSD showed language outcomes comparable to their peers with unilateral profound hearing loss. Children had poorer HRQoL psychosocial scores compared to physical scores, without obvious patterns of outcomes linked to degree or type of hearing loss.

Discussion

This study demonstrates children with early-identified unilateral or mild bilateral hearing loss have average language and HRQoL outcomes poorer than population normative expectations from an early age. These outcomes are observed at later ages across childhood. These findings provide a contemporary description of language and quality of life outcomes for children identified but not targeted by universal newborn hearing screening and raise questions of how to provide better support for these populations of children and their families.

Speech and Language outcomes in Auditory Neuropathy Spectrum Disorder (ANSD) children managed with amplification

OBJECTIVE

To evaluate speech and language outcomes in children with Auditory Neuropathy Spectrum Disorder (ANSD) without significant comorbidities who received hearing rehabilitation in the form of hearing aids and/or cochlear implantation.

METHODS

Retrospective chart review of pediatric ANSD patients at a large academic tertiary care institution from 2010 to 2019. Patients were included if they received a diagnosis of bilateral ANSD, had minimal to no comorbidities, and had speech and language testing (SLT) on at least two occasions.

RESULTS

51 patients were reviewed and 7 met inclusion criteria. Average age at ANSD diagnosis was 1 year and 11 months, and average age of hearing aid fitting was 3 years and 3 months. Hearing loss ranged from mild to profound, with four of the children wearing behind (BTE) hearing aids and three eventually receiving cochlear implants. Four of five patients who received hearing aids prior to their first speech and language evaluation demonstrated a delay at their initial evaluation, and all five patients continued to demonstrate a delay at their most recent evaluation, despite appropriate audiologic management and speech and language therapy. There were two patients who were unaided at the time of their initial and latest evaluations; one patient showed a delay at both timepoints, and one patient showed no speech delay at either timepoint.

CONCLUSIONS

Pediatric ANSD patients, who are otherwise typically developing and received hearing rehabilitation and speech and language therapy, continue to show a speech and language delay (SLD). This outcome underscores the importance of close monitoring of speech and language development, providing early amplification and/or cochlear implantation, and promoting additional education and psychosocial support.

Current Advances in Gene Therapies of Genetic Auditory Neuropathy Spectrum Disorder

Auditory neuropathy spectrum disorder (ANSD) refers to a range of hearing impairments characterized by an impaired transmission of sound from the cochlea to the brain. This defect can be due to a lesion or defect in the inner hair cell (IHC), IHC ribbon synapse (e.g., pre-synaptic release of glutamate), postsynaptic terminals of the spiral ganglion neurons, or demyelination and axonal loss within the auditory nerve. To date, the only clinical treatment options for ANSD are hearing aids and cochlear implantation. However, despite the advances in hearing-aid and cochlear-implant technologies, the quality of perceived sound still cannot match that of the normal ear. Recent advanced genetic diagnostics and clinical audiology made it possible to identify the precise site of a lesion and to characterize the specific disease mechanisms of ANSD, thus bringing renewed hope to the treatment or prevention of auditory neurodegeneration. Moreover, genetic routes involving the replacement or corrective editing of mutant sequences or defected genes to repair damaged cells for the future restoration of hearing in deaf people are showing promise. In this review, we provide an update on recent discoveries in the molecular pathophysiology of genetic lesions, auditory synaptopathy and neuropathy, and gene-therapy research towards hearing restoration in rodent models and in clinical trials.

Brain structure correlates with auditory function in children diagnosed with auditory neuropathy spectrum disorder

INTRODUCTION

Auditory neuropathy spectrum disorder (ANSD) is a term for a collection of test results which indicate disruption of the auditory signal at some point along the neural pathway. This results in a spectrum of functional outcomes, ranging from reasonably normal hearing to profound hearing loss. This study assessed brain structure changes and behavioral correlates in children diagnosed with ANSD.

METHODS

Seventeen children who had previously been diagnosed with ANSD were recruited to the study and underwent a battery of behavioral measures of hearing, language, and communication, along with structural MR imaging. Analysis of cortical thickness of temporal lobe structures was carried out using FreeSurfer. Tract-based spatial statistics were performed on standard diffusion parameters of fractional anisotropy and diffusivity metrics. The control group comprised imaging data taken from a library of MRI scans from neurologically normal children. Control images were matched as closely as possible to the ANSD group for age and sex.

RESULTS

Reductions in right temporal lobe cortical thickness were observed in children with ANSD compared to controls. Increases in medial diffusivity in areas including the corpus callosum and in the right occipital white matter were also seen in the group with ANSD compared to controls. Speech perception abilities, both in quiet and in noise, were correlated with cortical thickness measurements for several temporal lobe structures in children with ANSD, and relationships were also seen between diffusion metrics and measures of auditory function.

CONCLUSION

This study shows that children with ANSD have structural brain differences compared to healthy controls. It also demonstrates associations between brain structure and behavioral hearing abilities in children diagnosed with ANSD. These results show that there is a potential for structural imaging to be used as a biomarker in this population with the possibility of predicting functional hearing outcome.

[Electrically evoked ABR through cochlear implant in children with auditory neuropathy spectrum disorder]

OBJECTIVE

To estimate the applicability of electrically evoked auditory brainstem response (eABR) registration for the estimation of neural integrity after cochlear implantation (CI) in children with auditory neuropathy spectrum disorder (ANSD) and to compare the eABR data with patient's hearing performance.

MATERIAL AND METHODS

4 children, Nucleus (Cochlear) CI users, with ANSD were enrolled in the study. Hearing performance in these children ranged from successful to unsatisfied. eABR were recorded via Eclipse EP25 (Interacoustics). Electrical bipolar stimulation was achieved with Custom Sound EP software (Cochlear).

RESULTS

EABR were registered with the use of different stimulation parameters (pulse width, stimulated electrodes) in 3 patients with satisfactory results of rehabilitation. eABR thresholds corresponded to maximum comfortable levels of patients stimulation MAP. eABR were absent in the patient with poor hearing performance.

CONCLUSIONS

EABR measurements in children with ANSD demonstrated restoration of neuronal conduction in the auditory pathway up to the brainstem after cochlear implantation in 3 patients. eABR results were well correlated with hearing performance. Thereby, the study of eABR applicability for clinical practice will be expanded.

The Feasibility of the Functional Listening Index—Paediatric (FLI-P®) for Young Children with Hearing Loss

(1) Background: There is clear evidence supporting the need for individualized early intervention in children with hearing loss. However, relying on hearing thresholds and speech and language test results to guide intervention alone is problematic, particularly in infants and young children. This study aimed to establish the feasibility of a tool to monitor the development of functional listening skills to inform early and ongoing decisions by parents and professionals. (2) Methods: The FLI-P^® is a 64-item checklist completed by parents and/or a child’s team. The listening development of 543 children with hearing loss enrolled in an early intervention and cochlear implant program was tracked with the FLI-P over a 6-year period. The scores for individual children were grouped according to hearing loss, device, additional needs, and age at device fitting. (3) Results: Results indicate that the FLI-P is a feasible and viable clinical measure that can be used to identify and track a child’s developing listening skills. Its use across a wide range of children supports its broad application. Children’s individual scores and aggregated group data were consistent with indicated expected differences and variations. Children’s individual scores and aggregated group data indicated expected differences and variations. (4) Conclusions: Information provided by children’s listening scores on the FLI-P can guide and support discussions and intervention decisions and bridge the gap between information from audiological assessments and language measures.

Determination of language performance by discriminant function analysis in Mandarin-speaking preschoolers with auditory neuropathy spectrum disorder

OBJECTIVE

Characteristics of the audiological performance of children with auditory neuropathy spectrum disorder (ANSD) have been identified; however, studies regarding factors influencing their language development, especially those related to aural-oral rehabilitation, are relatively few. This study aimed to investigate classification functions among the factors regarding audiological, interventional (rehabilitation) and demographic variables that can help determine group membership in language performance for Mandarin-speaking preschoolers with ANSD.

METHODS

Children with ANSD aged 3-6 years (n = 27) enrolled in an auditory-verbal therapy were recruited. The combination of factors that could be used to predict memberships of children regarding whether they achieved age-appropriate language performance or were at risk of language delay were explored using discriminant function analysis.

RESULTS

Maternal education level, age at initial hearing aid fitting, and duration of rehabilitation were all significant factors in predicting the membership of children with ANSD and whether they could achieve an age-appropriate language level or were at risk for language delay. The correct rate for predicting the memberships ranged from 70.4% to 83.3%. Duration of rehabilitation accounted for the greatest effect on discriminant membership regarding achieving age-appropriate language performance and being at risk of language delay. Effect of maternal education level tended to centralize on language comprehension.

CONCLUSIONS

Differences were observed in the quantifiable effects of predictors in discriminant functions for language ability domains. Except for using suitable hearing devices, adequate duration of enrollment in aural and oral rehabilitation would also be important for children with ANSD to develop better language abilities.

[Auditory neuropathy and prematurity: modern view of the issue (literature review)]

Auditory neuropathy spectrum disorder (ANSD) is a specific auditory disorder caused by dysfunction of periphery part of the auditory system, in which the function of the outer hair cells is preserved, but the afferent input at the cochlear level suffers due to the pathology of the inner hair cells, neurons of the spiral ganglion and/or the auditory nerve, as well as synaptic contact between them. As a result, a specific condition is formed, in which a patient's otoacoustic emissions and/or cochlear microphonics are present, auditory brainstem responses are abnormal or absent, the discrepancy between the hearing level and the electrophysiological data, poor speech perception which may not correlate with the hearing thresholds. ANSD is a multifactorial disease. One of the main risk factors is perinatal pathology and, in particular, prematurity. The possible factors associated with prematurity that provoke the onset of the disease, features of the pathogenesis, clinical and audiological peculiarities of ANSD in premature infants, contemporary approaches to the habilitation of such patients are discussed in the article. The necessity of an individual, patient-oriented approach to the treatment of premature infants with ANSD is substantiated; such an approach should be based both on the genesis of the disorder, taking into account possible points of lesion in the auditory system, and the developmental peculiarities of a premature baby considering the presence of concomitant diseases associated with prematurity. In the article attention is focused on the main directions of habilitation work with such children, including a multidisciplinary approach, regular careful monitoring of the auditory, speech and language skills, intensive psychological and speech therapist support, the choice of an adequate way of intervention and its improvement as necessary.

Prevalence, risk factors, and audiological characteristics of auditory neuropathy

OBJECTIVE

The objective of this study was to determine the prevalence, risk factors, and audiological characteristics of auditory neuropathy spectrum disorder (ANSD) in the pediatric population.

DESIGN

A retrospective review of medical charts was conducted for children visiting two hospitals in Saudi Arabia.

STUDY SAMPLE

Medical records of 1025 patients with sensorineural hearing loss (SNHL) were reviewed. We analyzed the databases for results of audiological examinations, risk factors, and outcomes of intervention including hearing aid (HA) and cochlear implantation (CI).

RESULTS

Out of 1025 children with SNHL, 101 patients (9.85%) were identified to have ANSD. Audiological characteristics of the ANSD group revealed a severe-to-profound degree of hearing loss, all showed type A tympanogram and absent reflexes, absent auditory brainstem response (ABR) findings with present cochlear microphonic while otoacoustic emissions were absent in 54.5% of patients. The most prevalent risk factors for ANSD in this group were family history of hearing loss, consanguinity, hyperbilirubinemia, and low birth weight. Pure tone and speech detection thresholds improved significantly with CI compared to HA use in this sample of patients with ANSD.

CONCLUSION

This study shows that ANSD is not extremely rare among Saudi children with severe to profound hearing loss, with a prevalence of 9.85%.

Cochlear Implant Behavioral Outcomes for Children With Auditory Neuropathy Spectrum Disorder: A Mini-Systematic Review

Objective The aim of this mini-systematic review was to evaluate the evidence reporting speech, language, and auditory behavioral outcome measures for children with a diagnosis of auditory neuropathy spectrum disorder (ANSD) who received cochlear implants (CIs) prior to 3 years of age. Method A mini-systematic review of the literature supporting evidence-based practices was performed. Two databases were searched utilizing a search strategy derived from the PICO (patient, intervention, comparison, outcome) framework. Peer-reviewed articles published between 2009 and 2019 evaluating children with a diagnosis of ANSD who were implanted prior to 3 years of age with a range of speech, language, and auditory behavioral outcomes were included. Four articles meeting inclusion criteria were critically appraised for reputable research design and risks of bias. Each of the four studies was assigned a level of evidence for effectiveness and quality assessment rating. Results Evidence supports cochlear implantation as an appropriate intervention for children with ANSD. Improvements in outcome performance were observed in all the included studies. Children with ANSD fit with CIs can achieve outcomes similar to children with sensorineural hearing loss and CIs, despite the heterogeneity of ANSD. Conclusion These findings have implications for clinical practice and for future research with current CI technology for facilitating parent education, counseling, and realistic expectations for children with ANSD and CIs.

Fiber-Specific Changes in White Matter Microstructure in Individuals With X-Linked Auditory Neuropathy

OBJECTIVES

Auditory neuropathy (AN) is the term used to describe a group of hearing disorders, in which the hearing impairment occurs as a result of abnormal auditory nerve function. While our understanding of this condition has advanced significantly over recent years, the ability to determine the site of lesion and the extent of dysfunction in affected individuals remains a challenge. To this end, we investigated potential axonal degeneration in the white matter tracts of the brainstem in individuals with X-linked AN. We hypothesized that individuals with X-linked AN would show focal degeneration within the VIII nerve and/or auditory brainstem tracts, and the degree of degeneration would correlate with the extent of auditory perceptual impairment.

DESIGN

This was achieved using a higher-order diffusion magnetic resonance imaging (dMRI)-based quantitative measure called apparent fiber density as obtained from a technique called single-shell 3-tissue constrained spherical deconvolution and analyzed with the fixel-based analysis framework. Eleven subjects with genetically confirmed X-linked AN and 11 controls with normal hearing were assessed using behavioral and objective auditory measures. dMRI data were also collected for each participant.

RESULTS

Fixel-based analysis of the brainstem region showed that subjects with X-linked AN had significantly lower apparent fiber density in the VIII nerve compared with controls, consistent with axonal degeneration in this region. Subsequent analysis of the auditory brainstem tracts specifically showed that degeneration was also significant in these structures overall. The apparent fiber density findings were supported by objective measures of auditory function, such as auditory brainstem responses, electrocochleography, and otoacoustic emissions, which showed VIII nerve activity was severely disrupted in X-linked AN subjects while cochlear sensory hair cell function was relatively unaffected. Moreover, apparent fiber density results were significantly correlated with temporal processing ability (gap detection task) in affected subjects, suggesting that the degree of VIII nerve degeneration may impact the ability to resolve temporal aspects of an acoustic signal. Auditory assessments of sound detection, speech perception, and the processing of binaural cues were also significantly poorer in the X-linked AN group compared with the controls with normal hearing.

CONCLUSIONS

The results of this study suggest that the dMRI-based measure of apparent fiber density may provide a useful adjunct to existing auditory assessments in the characterization of the site of lesion and extent of dysfunction in individuals with AN. Additionally, the ability to determine the degree of degeneration has the potential to guide rehabilitation strategies in the future.

Can Differences in Early Hearing Development Be Distinguished by the LittlEARs Auditory Questionnaire?

OBJECTIVE

This study asks whether the LittlEARs Auditory Questionnaire (LEAQ), a caregiver measure, can differentiate between the early auditory development of children with bilateral cochlear implants (CIs), bilateral hearing aids (HAs), and children with Auditory Neuropathy Spectrum Disorder (ANSD) who wear CIs or HAs. The LEAQ is sensitive to impaired auditory development but has not previously been used to distinguish developmental changes between groups of children using different hearing technologies or with different types of hearing loss.

DESIGN

We collected retrospective longitudinal LEAQ results from 43 children with HAs, 43 with CIs, and 18 with ANSD. The children with ANSD wore hearing technology. They were a similar age to the children without ANSD (23 months; SD = 15), while the CI group (14 months; SD = 8) was younger than the HA group (24 months; SD = 18) [F(2,98.48) = 3.4; p = 0.04]. The CI group often participated in their first LEAQ pretreatment. Participants completed between one and seven LEAQs. Scores ranged between zero and 35 (mean = 18.36). We conducted a linear mixed-effects analysis, which included age or time since device fitting, hearing type (HA, CI, or ANSD), and presence of a comorbidity as fixed effects. A secondary analysis assessed effects of device audibility, measured by the Speech Intelligibility Index or Articulation Index, and consistency of device use obtained from device datalogs.

RESULTS

Children with CIs progressed faster than their peers with HAs or ANSD [χ2(8) = 24.51; p = 0.002]. However, within a subsample that included consistency of device use (β7 = -0.20 ± 0.38, t = -0.52; β8 = 0.93 ± 0.82, t = 1.13) and audibility (β6 = -0.70 ± 1.45, t = -1.87; β7 = 0.87 ± 0.89, t = 0.98), study group did not significantly influence rate of improvement on the LEAQ. In addition, children with developmental delays in all three study groups demonstrated significantly slower LEAQ score improvement [χ2(6) = 23.60; p < 0.001] and a trend toward decreased consistency of device use [F(1) = 3.31; p = 0.07]. As we expected, children in the CI and HA groups were more likely to achieve auditory skills indicated in early rather than later LEAQ questions. There was less variability in the responses of the ANSD group [CI: interquartile range (IQR) = 9; HA: IQR = 8; ANSD: IQR = 1]. There was no connection between LEAQ growth and speech perception outcomes in a subsample [r(6) = 0.42; p = 0.30].

CONCLUSIONS

The LEAQ is a useful tool for monitoring initial auditory development in very young children and can inform early treatment decisions.

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.

Music and psychoacoustic perception abilities in cochlear implant users with auditory neuropathy spectrum disorder

OBJECTIVE

Auditory neuropathy spectrum disorder (ANSD) is a condition wherein the pre-neural or cochlear outer hair cell activity is intact, but the neural activity in the auditory nerve is disrupted. Cochlear implant (CI) can be beneficial for subjects with ANSD; however, little is known about the music perception and psychoacoustic abilities of CI users with ANSD. Music perception in CI users is a multidimensional and complex ability requiring the contribution of both auditory and nonauditory abilities. Even though auditory abilities lay the foundation, the contribution of patient-related variables such as ANSD may affect the music perception. This study aimed to evaluate the psychoacoustic and music perception abilities of CI recipients with ANSD.

STUDY DESIGN

Twelve CI users with ANSD and twelve age- and gendermatched CI users with sensorineural hearing loss (SNHL) were evaluated. Music perception abilities were measured using the Turkish version of the Clinical Assessment of Music Perception (T-CAMP) test. Psychoacoustic abilities were measured using the spectral ripple discrimination (SRD) and temporal modulation transfer function (TMTF) tests. In addition, the age of diagnosis and implantation was recorded.

RESULTS

Pitch direction discrimination (PDD), timbre recognition, SRD, and TMTF performance of CI users with ANSD were concordant with those reported in previous studies, and differences between ANSD and SNHL groups were not statistically significant. However, the ANSD group performed poorly compared with SNHL group in melody recognition subtest of T-CAMP, and the difference was statistically significant.

CONCLUSION

CI can prove beneficial for patients with ANSD with respect to their music and psychoacoustic abilities, similar to patients with SNHL, except for melody recognition. Recognition of melodies requires both auditory and non-auditory abilities, and ANSD may have an extensive but subtle effect in the life of CI users.

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.

Auditory and speech performance in cochlear implanted ANSD children

BACKGROUND

Auditory neuropathy spectrum disorder (ANSD) is a distinct type of SNHL that is characterized by the presence of otoacoustic emissions and/or cochlear microphonics. Cochlear implantation was initially not recommended for ANSD children, later studies showed variable outcomes among those subjects.

OBJECTIVE

To assess the auditory and speech performance of cochlear implanted children with auditory neuropathy spectrum disorder (ANSD) and to compare these results to those obtained from cochlear implanted children with sensorineural hearing loss (SNHL) Material and methods: 18 cochlear implanted children with ANSD and 40 cochlear implanted children with SNHL were included in this study. Auditory and speech performance results were compared across both subject groups using the Category of Auditory Performance (CAP) and Speech Intelligibility Rate (SIR) tests, with measurements recorded one year post implantation.

RESULTS

Cochlear implanted children with ANSD showed clinically significant improvements that were comparable to those observed from cochlear implanted subjects without ANSD.

CONCLUSIONS

Children with ANSD benefit from early cochlear implantation and can reach similar auditory and speech performance results as that achieved by children without ANSD.

Auditory Neuropathy: Bridging the Gap Between Hearing Aids and Cochlear Implants

Auditory neuropathy spectrum disorder (ANSD) is a complex and heterogeneous disorder associated with altered neural synchrony with respect to auditory stimuli. Patients have characteristic auditory findings including normal otoacoustic emissions in the setting of abnormal auditory brainstem response. Patients with ANSD have a high incidence of comorbid developmental delay that may impact speech outcomes. Treatment options for ANSD include hearing amplification and cochlear implantation. The article highlights issues and controversies with the diagnosis and treatment of this complex disorder.

Hearing Impairment Among Children Referred to a Public Audiology Clinic in Gaborone, Botswana

Objective. To describe and quantify hearing impairment among children referred to the audiology clinic in Princess Marina Hospital, a public referral hospital in Botswana. Methods. In a retrospective case series, we reviewed medical records of children aged 10 years and younger whose hearing was assessed between January 2006 and December 2015 at the audiology clinic of Princess Marina Hospital in Gaborone, Botswana. Results. Of 622 children, 50% were male, and median age was 6.7 years (interquartile range = 5.0-8.3). Hearing impairment was diagnosed in 32% of clinic attendees, comprising sensorineural (23%), conductive (25%), and mixed (11%) hearing loss, while 41% of children with diagnosed hearing impairment did not have a classification type. Hearing impairment was mild in 22.9%, moderate in 22.4%, severe in 19.4%, profound in 16.9%, and of undocumented severity in 18.4%. Children younger than 5 years were 2.7 times (95% confidence interval = 1.29-5.49; P = .008) more likely to be diagnosed with sensorineural hearing impairment compared with those older than 5 years. By contrast, children older than 5 years were 9.6 times (95% confidence interval = 2.22-41.0; P = .002) more likely to be diagnosed with conductive hearing loss compared with those under 5 years. Conclusion. Hearing impairment was common among children referred to this audiology clinic in Botswana. Of those with hearing impairment, more than a third had moderate or severe deficits, suggesting that referrals for hearing assessments are not occurring early enough. Hearing awareness programs individually tailored to parents, educators, and health care workers are needed. Neonatal and school hearing screening programs would also be beneficial.

Children with Auditory Neuropathy Spectrum Disorder Fitted with Hearing Aids Applying the American Academy of Audiology Pediatric Amplification Guideline: Current Practice and Outcomes

BACKGROUND

Up to 15% of children with permanent hearing loss (HL) have auditory neuropathy spectrum disorder (ANSD), which involves normal outer hair cell function and disordered afferent neural activity in the auditory nerve or brainstem. Given the varying presentations of ANSD in children, there is a need for more evidence-based research on appropriate clinical interventions for this population.

PURPOSE

This study compared the speech production, speech perception, and language outcomes of children with ANSD, who are hard of hearing, to children with similar degrees of mild-to-moderately severe sensorineural hearing loss (SNHL), all of whom were fitted with bilateral hearing aids (HAs) based on the American Academy of Audiology pediatric amplification guidelines.

RESEARCH DESIGN

Speech perception and communication outcomes data were gathered in a prospective accelerated longitudinal design, with entry into the study between six mo and seven yr of age. Three sites were involved in participant recruitment: Boys Town National Research Hospital, the University of North Carolina at Chapel Hill, and the University of Iowa.

STUDY SAMPLE

The sample consisted of 12 children with ANSD and 22 children with SNHL. The groups were matched based on better-ear pure-tone average, better-ear aided speech intelligibility index, gender, maternal education level, and newborn hearing screening result (i.e., pass or refer).

DATA COLLECTION AND ANALYSIS

Children and their families participated in an initial baseline visit, followed by visits twice a year for children <2 yr of age and once a yr for children >2 yr of age. Paired-sample t-tests were used to compare children with ANSD to children with SNHL.

RESULTS

Paired t-tests indicated no significant differences between the ANSD and SNHL groups on language and articulation measures. Children with ANSD displayed functional speech perception skills in quiet. Although the number of participants was too small to conduct statistical analyses for speech perception testing, there appeared to be a trend in which the ANSD group performed more poorly in background noise with HAs, compared to the SNHL group.

CONCLUSIONS

The American Academy of Audiology Pediatric Amplification Guidelines recommend that children with ANSD receive an HA trial if their behavioral thresholds are sufficiently high enough to impede speech perception at conversational levels. For children with ANSD in the mild-to-severe HL range, the current results support this recommendation, as children with ANSD can achieve functional outcomes similar to peers with SNHL.

Clinical role of electrocochleography in children with auditory neuropathy spectrum disorder

OBJECTIVES

To assess electrocochleography (ECochG) to tones as an instrument to account for CI speech perception outcomes in children with auditory neuropathy spectrum disorder (ANSD).

MATERIALS & METHODS

Children (<18 years) receiving CIs for ANSD (n = 30) and non-ANSD (n = 74) etiologies of hearing loss were evaluated with ECochG using tone bursts (0.25-4 kHz). The total response (TR) is the sum of spectral peaks of responses across frequencies. The compound action potential (CAP) and the auditory nerve neurophonic (ANN) in ECochG waveforms were used to estimate nerve activity and calculate nerve score. Performance on open-set monosyllabic word tests was the outcome measure. Standard statistical methods were applied.

RESULTS

On average, TR was larger in ANSD than in non-ANSD subjects. Most ANSD (73.3%) and non-ANSD (87.8%) subjects achieved open-set speech perception; TR accounted for 33% and 20% of variability in the outcomes, respectively. In the ANSD group, the PTA accounted for 69.3% of the variability, but there was no relationship with outcomes in the non-ANSD group. In both populations, nerve score was sensitive in identifying subjects at risk for not acquiring open-set speech perception, while the CAP and the ANN were more specific.

CONCLUSION

In both subject groups, the TRs correlated with outcomes but these measures were notably larger in the ANSD group. There was also strong correlation between PTA and speech perception outcome in ANSD group. In both subject populations, weaker evidence of neural activity was related to failure to achieve open-set speech perception.

Detection Rates of Cortical Auditory Evoked Potentials at Different Sensation Levels in Infants with Sensory/Neural Hearing Loss and Auditory Neuropathy Spectrum Disorder

With the introduction of newborn hearing screening, infants are being diagnosed with hearing loss during the first few months of life. For infants with a sensory/neural hearing loss (SNHL), the audiogram can be estimated objectively using auditory brainstem response (ABR) testing and hearing aids prescribed accordingly. However, for infants with auditory neuropathy spectrum disorder (ANSD) due to the abnormal/absent ABR waveforms, alternative measures of auditory function are needed to assess the need for amplification and evaluate whether aided benefit has been achieved. Cortical auditory evoked potentials (CAEPs) are used to assess aided benefit in infants with hearing loss; however, there is insufficient information regarding the relationship between stimulus audibility and CAEP detection rates. It is also not clear whether CAEP detection rates differ between infants with SNHL and infants with ANSD. This study involved retrospective collection of CAEP, hearing threshold, and hearing aid gain data to investigate the relationship between stimulus audibility and CAEP detection rates. The results demonstrate that increases in stimulus audibility result in an increase in detection rate. For the same range of sensation levels, there was no difference in the detection rates between infants with SNHL and ANSD.

The Role of the World Health Organization's International Classification of Functioning, Health and Disability in Models of Infant Cochlear Implant Management

Newborn hearing screening has led to the early diagnosis of hearing loss in neonates and early device fitting is common, based primarily on electrophysiologic and radiologic information, with some supplementary behavioral measures. Such early fitting of hearing devices, in particular cochlear implants (CIs), has been beneficial to the majority of children implanted under the age of 12 months who meet the cochlear implant candidacy criteria. Comorbidities are common in children with hearing loss, although they may not be evident in neonates and may not emerge until later in infants. Evidence suggests that the child's outcomes are strongly influenced by a range of environmental factors including emotional and social support from the immediate and extended family. Consequently, such factors are important in service planning and service delivery for babies and children receiving CIs. The World Health Organization's International Classification of Functioning, Health and Disability (ICF) can provide a framework to facilitate the holistic management of pediatric cochlear implant recipients. The ICF also can be used to map the progress of recipients over time to highlight emerging issues that require intervention. This article will discuss our preliminary use of the ICF to establish clinical practice; develop advocacy skills among clients and their families; identify eligibility for services such as support in educational settings; enable access to modes of service delivery such as telepractice; provide a conceptual framework for policy and program development for pediatric cochlear implant recipients (i.e., in both disability and health services); and, most importantly, establish a clear pathway for the longitudinal management of the cochlear implant in a child's future. It is anticipated that this model will be applied to other populations receiving cochlear implants through our program.

Auditory neuropathy--neural and synaptic mechanisms

Sensorineural hearing impairment is the most common form of hearing loss, and encompasses pathologies of the cochlea and the auditory nerve. Hearing impairment caused by abnormal neural encoding of sound stimuli despite preservation of sensory transduction and amplification by outer hair cells is known as 'auditory neuropathy'. This term was originally coined for a specific type of hearing impairment affecting speech comprehension beyond changes in audibility: patients with this condition report that they "can hear but cannot understand". This type of hearing impairment can be caused by damage to the sensory inner hair cells (IHCs), IHC ribbon synapses or spiral ganglion neurons. Human genetic and physiological studies, as well as research on animal models, have recently shown that disrupted IHC ribbon synapse function--resulting from genetic alterations that affect presynaptic glutamate loading of synaptic vesicles, Ca(2+) influx, or synaptic vesicle exocytosis--leads to hearing impairment termed 'auditory synaptopathy'. Moreover, animal studies have demonstrated that sound overexposure causes excitotoxic loss of IHC ribbon synapses. This mechanism probably contributes to hearing disorders caused by noise exposure or age-related hearing loss. This Review provides an update on recently elucidated sensory, synaptic and neural mechanisms of hearing impairment, their corresponding clinical findings, and discusses current rehabilitation strategies as well as future therapies.

Auditory neuropathy spectrum disorder (ANSD) and cochlear implantation

We discuss issues related to cochlear implantation in children with auditory neuropathy spectrum disorder (ANSD). We describe the varied nature of this disease category including the numerous potential causes of auditory neuropathy. The most prevalent etiology for infants with ANSD is associated with prolonged neonatal intensive care unit (NICU) stay. We discuss the potential contribution of cochlear hypoxia to this etiology. The second part of this review describes in detail our own experience at the Hospital for Sick Children in Toronto, with cochlear implantation of children diagnosed with ANSD. We outline the detection, diagnosis, and referral routes for our patients. We provide an overview of our "standard operation procedures" regarding candidacy, and discuss some of the special considerations that need to be applied to children with ANSD. This includes decisions to implant children with better audiometric thresholds that are standard in non-ANSD patients, concerns about the possibility of spontaneous remission and the appropriate timing of implantation. Finally we review an extensive published literature in outcomes after cochlear implantation (CI) in ANSD. This is not a systematic review but rather an exercise to distill out some important reoccurring themes and the general consensus of opinion to date. Our conclusion is that the hearing loss category ANSD, together with its numerous co-morbidities, is far too heterogeneous to make definitive statements about prognosis with CI.

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.

Auditory Neuropathy/Dys-Synchrony Disorder: Diagnosis and Management

Auditory neuropathy/dys-synchrony disorder affects neural responses, either directly or indirectly. Patients may demonstrate good ability to detect sound, but have significant difficulty listening in noise. Clinical auditory physiologic measures are used to characterize cochlear, eighth nerve, and brainstem function, and are needed to accurately identify this disorder. Cochlear implants provide benefit to many patients, and some patients derive benefit from amplification. This disorder can be identified and managed in infants, may have later onset, may be a part of a syndrome, and may include fluctuation in hearing ability.

Auditory neuropathy

Neural disorders of the auditory nerve are associated with particular disorders of auditory perceptions dependent on processing of acoustic temporal cues. These include: (1) speech perception; (2) localizing a sound's origin in space; and (3) identifying sounds in background noise. Auditory neuropathy (AN) is a consequence of: (1) presynaptic disorders affecting inner hair cell ribbon synapses; (2) postsynaptic disorders of auditory nerve dendrites; and (3) postsynaptic disorders of auditory nerve axons. The etiologies of these disorders are diverse, similar to other cranial or peripheral neuropathies. The pathologies cause attenuated and dyssynchronous auditory nerve discharges. Therapies and management of patients with AN are reviewed.

Profound childhood hearing loss in a South Africa cohort: risk profile, diagnosis and age of intervention

OBJECTIVE

To describe profound childhood hearing loss in a South African population of pediatric cochlear implant recipients in terms of risk profile, and age of diagnosis and intervention.

METHODS

A retrospective review of patient files for 264 pediatric cochlear implant recipients from five cochlear implant programs was conducted. Data was captured from 264 eligible subjects, of which all were implanted between 1996 and 2013 and PCEHL was confirmed under the age of 5 years old. Data collected included demographical information, risk factors from case histories, diagnostic test procedures conducted, diagnosis (type, onset and degree of hearing loss) and documented ages of caregiver suspicion, initial diagnosis and intervention.

RESULTS

Risk factors for permanent childhood hearing loss were present in 51.1% of cases, with the most prevalent risks being NICU admittance (28.1%), family history of childhood hearing loss (19.6%) and prematurity (15.1%). An associated syndrome was diagnosed in 10% of children and 23.5% presented with at least one additional developmental condition. Hearing loss for most (77.6%) children was confirmed as congenital/early onset, while 20.3% presented with postnatal onset of hearing loss. ANSD was diagnosed in 5% of children, with admittance to NICU (80%) and hyperbilirubinemia (50%) being the most prevalent risk factors for these cases. Hearing loss was typically diagnosed late (15.3 months), resulting in delayed initial hearing aid fitting (18.8 months), enrollment in early intervention services (19.5 months) and eventual cochlear implantation (43.6 months).

CONCLUSION

Most prevalent risk factors in profound childhood hearing loss were admittance to NICU, family history and prematurity. Diagnosis and intervention was typically delayed predisposing this population to poorer outcomes.

Major findings of the LOCHI study on children at 3 years of age and implications for audiological management

OBJECTIVE

This article describes the major findings of the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study.

DESIGN

A population-based prospective cohort study; with randomized controlled trials of hearing aid prescription and non-linear frequency compression.

SAMPLE

451 children in New South Wales, Victoria and Southern Queensland.

RESULTS

Significant predictors of language outcomes at 3 years of age included severity of hearing loss, gender, presence of additional disabilities, maternal education, and age at cochlear implantation. Although prescription did not have a significant effect on outcomes, its influence on loudness and hearing aid safety has implications for management. After controlling for a range of predictor variables, nonlinear frequency compression did not have a significant effect on outcomes. For the same hearing sensitivity, the presence of auditory neuropathy did not have a significant effect on outcomes.

CONCLUSIONS

These findings form the basis for evidence-based guidelines for management of children with hearing loss.