Auditory Neuropathy Spectrum Disorder Research Articles

Gender differences in contralateral suppression of spontaneous otoacoustic emissions in individuals with auditory neuropathy spectrum disorders.

The current study aims to evaluate gender variations in the efferent auditory system functioning in the ANSD population and compare them to normal hearing persons using contralateral suppression of spontaneous OAE (SOAEs). For the current study, a total of 54 ears were considered prospectively. 27 ears with normal hearing (NH) sensitivity were in group I, while 27 ears with ANSD were in group II. All of the subjects had a regular audiological examination followed by synchronised SOAE recordings with and without broadband noise (in the contralateral ear) at 50dB SPL and statistical analysis was carried out. Wilcoxon signed rank test revealed a significant decrease in SOAE amplitude with contralateral noise stimulation in NH, while no such trend was observed in ANSD. However, contralateral SOAE stimulation resulted in significant high-frequency shifts for both the ANSD and NH groups in the noise condition. In the comparison of gender effects on SOAE amplitude and frequency shifts using Mann-Whitney, no significant gender differences were seen. The lack of gender differences in SOAE suppression is explained based on global standing wave theory and local oscillator theory. Contralateral effect of noise on SOAE shows frequency shifts, but not amplitude shifts both of which are not affected by gender effects.

Effect of Sensory Modality on Reaction Time in Individuals with Auditory Neuropathy Spectrum Disorder

PurposeTo investigate and compare the reaction time of individuals with auditory neuropathy in three modalities, auditory, visual, and audio-visual. The reaction time of individuals with auditory neuropathy was also compared with those with normal hearing. The relationship between reaction time across modalities and the duration of hearing loss in auditory neuropathy was also investigated. Methods and MaterialsThe reaction time of adults with auditory neuropathy and those with normal hearing was measured in the three modalities using the Choice reaction time task. ResultsThe auditory neuropathy group significantly had a longer reaction time than the normal hearing in all modalities. The trend of the mean reaction time differed across groups. Further, a significant difference in reaction time of the auditory neuropathy group was noted between auditory and visual mode, auditory and audio-visual mode. However, no significant difference between visual and audio-visual modalities was noted in reaction time. ConclusionSignificantly longer reaction time in auditory neuropathy is presumed to have resulted from neural conduction delay and impaired processing. The auditory neuropathy group can utilize visual cues for faster processing, and the study recommends an audio-visual mode for their management. In addition, the duration of hearing loss in auditory neuropathy had no relationship with reaction time across all modalities.

Do cochlear microphonics evoked by narrow-band chirp stimuli affect the objective detection of auditory steady-state responses?

Objective It has recently been discussed whether hearing screening and hearing threshold assessment can accurately be completed using automated ASSR methods for children with auditory neuropathy spectrum disorder (ANSD). Possible causes for the claimed potential failures were investigated here. Design The study is based on the analysis of stored ASSR raw data. Study sample This study reviewed raw ASSR data from 274 patients with a total of 5809 individual recordings. Results Cochlear microphonics (CM) were found in 18 of the 274 patient records. Four of these 18 were obtained from patients with ANSD. One patient with ANSD without click auditory brainstem responses up to 100 dBnHL demonstrated clear ASSR responses from 65 dBnHL upwards. Where click stimulation suggests an auditory nerve defect, narrow-band chirps were shown to evoke ASSR in certain patients. CMs are elicited by narrow-band chirps in the same way as by broadband stimuli. CM residuals as well as a presumed enlarged wave I with absent neural responses, always accompanied by CM, were found as possible causes of misinterpretation at high stimulus levels. A CM detector was created. Conclusions The CM detector, indicating the presence of CM, will prevent misinterpretation of clinical ASSR results.

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

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. 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. 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. 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.

Outcomes of Gene Panel Testing for Sensorineural Hearing Loss in a Diverse Patient Cohort

A genetic diagnosis can help elucidate the prognosis of hearing loss, thus significantly affecting management. Previous studies on diagnostic yield of hearing loss genetic tests have been based on largely homogenous study populations. To examine the diagnostic yield of genetic testing in a diverse population of children, accounting for sociodemographic and patient characteristics, and assess whether these diagnoses are associated with subsequent changes in clinical management. This retrospective cohort study included 2075 patients seen at the Children's Communications Clinic, of whom 517 completed hearing loss gene panel testing between January 1, 2015, and November 1, 2021, at the University of California, San Francisco Benioff Children's Hospital system. From those 517 patients, 426 children with at least 2 audiograms were identified and analyzed. Data were gathered from November 2021 to January 2022 and analyzed from January to February 2022. The measures of interest were sociodemographic characteristics (age at testing, gender, race and ethnicity, primary language, and insurance type), hearing loss characteristics, and medical variables. The outcome was genetic testing results. Variables were compared with univariate and multivariable logistic regression. Of the 2075 patients seen at the Children's Communications Clinic, 517 (median [range] age, 8 [0-31] years; 264 [51.1%] male; 351 [67.9%] from an underrepresented minority [URM] group) underwent a hearing loss panel genetic test between January 1, 2015, and November 1, 2021. Among those 517 patients, 426 children (median [range] age, 8 [0-18] years; 221 [51.9%] male; 304 [71.4%] from an URM group) with 2 or more audiograms were included in a subsequent analysis. On multivariable logistic regression, age at testing (odds ratio [OR], 0.87; 95% CI, 0.78-0.97), URM group status (OR, 0.29; 95% CI, 0.13-0.66), comorbidities (OR, 0.27; 95% CI, 0.14-0.53), late-identified hearing loss (passed newborn hearing screen; OR, 0.27; 95% CI, 0.08-0.86), and unilateral hearing loss (OR, 0.04; 95% CI, 0.005-0.33) were the only factors associated with genetic diagnosis. No association was found between genetic diagnosis yield and other sociodemographic variables or hearing loss characteristics. Patients in URM and non-URM groups had statistically similar clinical features. A total of 32 of 109 children (29.4%) who received a genetic diagnosis received diagnoses that significantly affected prognosis because of identification of syndromic or progressive sensorineural hearing loss or auditory neuropathy spectrum disorder relating to otoferlin. This cohort study's findings suggest that genetic testing may be broadly useful in improving clinical management of children with hearing loss. More research is warranted to discover and characterize diagnostic genes for those who have been historically underrepresented in research and medicine.

How Craniofacial Anomalies Can Obscure the Diagnosis of Unilateral Auditory Neuropathy Spectrum Disorder: A Case Study.

Comorbidities are common with craniofacial anomalies and can include auditory neuropathy spectrum disorder (ANSD). Identification of these comorbidities, such as a diagnosis of ANSD, has increased with expanded multi-disciplinary care teams and the use of auditory objective measures. Patients with craniofacial anomalies often have complex medical histories including extreme prematurity and jaundice, which may lead to the development of additional comorbidities. The 5-year-old boy that is the subject of this case study presented with noted developmental delays and residing in foster care with an unknown family/medical history. Initially presenting with middle ear dysfunction, exacerbated by craniofacial anomalies, the underlying cause of his speech delays was missed. Behavioral audiometry was attempted with inaccurate results. Surgery was performed to correct the craniofacial anomalies, middle ear dysfunction, and was followed with auditory brainstem response (ABR) testing. The boy healed well without complications. The ABR revealed ANSD, hearing aids were fitted for the diagnosis, regular speech therapy was initiated, and the boy continues to make steady progress toward developmental milestones. The purpose of this case study was to highlight the course of identification and treatment of a complex case that may provide insight into determining a differential diagnosis of ANSD when initially obscured by craniofacial anomalies.

Profiles and predictors of onset based differences in vocal characteristics of adults with auditory neuropathy spectrum disorder (ANSD)

PurposeOnset-based differences are understudied in Auditory Neuropathy Spectrum Disorder (ANSD) in dimensions such as voice, which is addressed in the study. The study aimed to profile and predict the best metrics of onset-related differences in acoustic vocal characteristics of early and late-onset ANSD patients. Methods31 participants (15 early and 16 late-onset) aged 15–30 years diagnosed with ANSD were included in the study. The sustained phonation of vowel /i/ recorded by the participants using android based smartphones of selected configuration was sent over email to the experimenter. Acoustic parameters (fundamental frequency, harmonic frequencies, jitter, shimmer, harmonic-to-noise ratio, cepstral peak prominence -CPP, and pitch sigma) were analysed using Praat software. ResultsResults revealed significantly increased (p < 0.05) fundamental frequency along with decreased F2 and F3 of /i/ in the early-onset ANSD compared to the late-onset group, which can be explained based on differences in the pathophysiology of the disorder. Although not statistically significant, mean perturbations (jitter and shimmer), harmonic-to-noise ratio, cepstral peak prominence, and pitch sigma were more affected in the early-onset group, reflective of lowered auditory feedback and periodicity in their voice samples. Results of discriminant analysis marked the emergence of F2, F3, and CPP as the most sensitive metrics for onset-based group differences in voice characteristics. ConclusionsThe findings from the study highlight the role of acoustical voice evaluation (especially CPP, F2 & F3) in verifying the onset of ANSD disorder. The insights from the onset-based differences seen in vocal characteristics can indirectly help audiologists in deciding the management options for ANSD.

Round Window Electrocochleography to Low Frequency Tones in Pediatric Cochlear Implant Recipients with and Without Auditory Neuropathy Spectrum Disorder: Separating Hair Cell and Neural Contributions Using a Computational Model.

Characterize the contribution of the auditory nerve neurophonic (ANN) to electrocochleography (ECochG) of pediatric cochlear implant (CI) recipients with and without auditory nerve spectrum disorder (ANSD). ECochG is an emerging technique for predicting outcomes in CI recipients. Its utility may be increased by separating the cochlear microphonic (CM), produced by hair cells, from the ANN, the evoked potential correlate of neural phase-locking, which are mixed in the ongoing portion of the response to low frequency tone bursts. Responses to tone bursts of different frequency and intensities were recorded from the round window of pediatric CI recipients. Separation of the CM and ANN was performed using a model of the underlying processes that lead to the shapes of the observed waveforms. Preoperative mean pure tone amplitudes of the included ANSD (n = 36) and non-ANSD subjects (n = 123), were similar (89.5 and 93.5, p = 0.1). Total of 1,024 ECochG responses to frequency and intensity series were recorded. The mean correlation ( r ) between the input and the modeled signals was 0.973 ± 0.056 (standard deviation). The ANN magnitudes were higher in the ANSD group (ANOVAs, F = 26.5 for frequency and 21.9 for intensity, df's = 1, p 's < 0.001). However, its relative contribution to the overall signal was lower (ANOVAs, F = 25.8 and 12.1, df = 1, p 's < 0.001). ANN was detected in low frequency ECochG responses but not high frequency responses in both ANSD and non-ANSD subjects. ANSD subjects, evidence of neural contribution in responses to low frequency stimuli was highly variable and often comparable to signals recorded in non-ANSD subjects. The computational model revealed that on average the ANN comprised a lower proportion of the overall signal than in non-ANSD subjects.

Cochlear Implantation Outcomes in Patients with Auditory Neuropathy Spectrum Disorder of Genetic and Non-Genetic Etiologies: A Multicenter Study.

With diverse etiologies and clinical features, the management of pediatric auditory neuropathy spectrum disorder (ANSD) is often challenging, and the outcomes of cochlear implants (CIs) are variable. This study aimed to investigate CI outcomes in pediatric patients with ANSD of different etiologies. Thirty-six children with ANSD who underwent cochlear implantation between 2001 and 2021 were included. Comprehensive etiological analyses were conducted, including a history review, next-generation sequencing-based genetic examinations, and imaging studies using high-resolution computed tomography and magnetic resonance imaging. Serial behavioral and speech audiometry were performed before and after surgery, and the outcomes with CI were evaluated using the Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores. By etiology, 18, 1, 1, and 10 patients had OTOF-related, WFS1-related, OPA1-related, and cochlear nerve deficiency (CND)-related ANSD, respectively. Six patients had no definite etiology. The average CI-aided behavioral threshold was 28.3 ± 7.8 dBHL, and those with CND-related ANSD were significantly worse than OTOF-related ANSD. The patients’ median CAP and SIR scores were 6 and 4, respectively. Favorable CI outcomes were observed in patients with certain etiologies of ANSD, particularly those with OTOF (CAP/SIR scores 5–7/2–5), WFS1 (CAP/SIR score 6/5), and OPA1 variants (CAP/SIR score 7/5). Patients with CND had suboptimal CI outcomes (CAP/SIR scores 2–6/1–3). Identifying the etiologies in ANSD patients is crucial before surgery and can aid in predicting prognoses.

Auditory Neuropathy Spectrum Disorder in Brown- Vialetto-Van Laere Syndrome

Background and Aim: This study shows the clinical symptoms pertinent to auditory neuropathy spectrum disorder (ANSD) for a 16-year-old girl with Brown-Vialetto-Van Laere Syndrome (BVVL). The results have been followed for six years between 2015 and 2021.&#x0D; The Case: In the present study, auditory test battery including tympanometry, acoustic reflex, pure tone audiometry, transient evoked otoacoustic emissions and auditory brainstem response were utilized and repeated three times during six years.&#x0D; Conclusion: In the first session, the results revealed bilaterally normal transient evoked otoacoustic emissions, absent acoustic reflexes (ipsilateral and contralateral), mild to moderate low tone loss in the pure tone audiometry, no auditory brain stem responses at high stimulus intensities and different polarities and present cochlear microphonic component in single polarities. In the second session, pure tone audiometry showed slight to mild high tone loss but the other tests demonstrated their same results. In the final session, the latter results were repeated. In this comprehensive follow up study, the patient with BVVL demonstrated clinical symptoms of auditory neuropathy spectrum disorder in which auditory system showed an impairment in the auditory temporal synchronization and encoding.&#x0D; Keywords: Brown-Vialetto-Van Laere syndrome; auditory neuropathy spectrum disorder; auditory brainstem response; pure tone audiometry

Audiological Findings in Children with PLA2G6-Associated Neurodegeneration.

Audiological manifestations of patients with PLA2G6-associated neurodegeneration are limited. To analyze the audiological findings in a cohort of 13 children with infantile neuroaxonal dystrophy (INAD). Patients underwent a battery of audiological tests including tympanometry, distortion product otoacoustic emissions, impedance audiometry, and Brainstem Auditory Evoked Potentials (BAEPs). Audiological studies of 13 children indicated sensorineural hearing loss in six children and auditory neuropathy spectrum disorder in four children. This study may extend the auditory findings for INAD. Additional studies on quality of life and cognitive-brain degeneration related to this disease are required before making appropriate recommendations for aural rehabilitation.

Cochlear nerve deficiency is an important cause of auditory neuropathy spectrum disorder at a population level in children

ObjectivesTo determine the incidence, prevalence and describe risk factors and etiology for childhood Auditory Neuropathy Spectrum Disorder using population level data from a statewide universal newborn hearing program. MethodsA retrospective statewide universal newborn hearing screening database review and descriptive analysis from 2012 to 2019 of demographic, risk factors and hearing loss etiology for babies with sensorineural hearing loss and ANSD was completed. A 2 stage aABR protocol was used and ANSD was classified when click evoked ABR were absent or grossly abnormal but otoacoustic emissions and or cochlear microphonics were present. Medical evaluation and investigation by a pediatrician or otolaryngologist was performed and etiology was assigned using a coding scheme. Next generation genetic sequencing was not available. ResultsFrom 2012 to 2019, 487 636 babies were screened for congenital hearing loss (99.1%) and 1150 were confirmed to have permanent SNHL, 80 of whom were diagnosed with ANSD (52 unilateral and 28 bilateral). The prevalence of ANSD was 7.0% and population prevalence was 0.16 per 1000 live births. The only demographic or risk factor significantly more likely to be associated with ANSD than SNHL was hyperbilirubinemia. The most common etiology for ANSD was hypoplasia or absence of the cochlear nerve with 37 cases (46.3%), and it was significantly more likely with unilateral than bilateral ANSD. ConclusionAt a population level, ANSD was more likely to be unilateral and the only perinatal risk factor significantly associated was hyperbilirubinemia. Cochlear nerve deficiency was the most common etiology. Given that this can occur in well babies, this provides further evidence for aABR as a preferred mode for newborn hearing screening.

Auditory and Speech Outcomes of Cochlear Implantation in Children With Auditory Neuropathy Spectrum Disorder: A Systematic Review and Meta-Analysis.

The aim of this meta-analysis was to critically assess the effect of cochlear implantation on auditory and speech performance outcomes of children with auditory neuropathy spectrum disorder (ANSD). A systematic literature search was conducted on PubMed, EMbase, and Web of Science. The outcomes included speech recognition score, Categories of Auditory Performance (CAP), Speech Intelligibility Rating (SIR) score, and open-set speech perception. Results were expressed as standardized mean difference (SMD) or risk ratio (RR) with a 95% confidence interval (95% CI). A total of 15 studies was included in this meta-analysis. Pooled data showed that, there were no significant differences between ANSD and sensorineural hearing loss (SNHL) groups in terms of speech recognition score (SMD = 0.01, 95% CI: -0.45, 0.47; P = .959),CAP (SMD = 0.71, 95% CI: -0.13, 1.54; P = .098), SIR score (SMD = -0.09, 95% CI: -0.49, 0.32; P = .667), and open-set speech perception (RR = 0.85, 95% CI: 0.69, 1.05; P = .142). Sensitivity analysis by removing individual studies one at a time showed that the overall estimate and level of heterogeneity did not change substantially. The current evidence suggested that children with ANSD who underwent cochlear implants achieved comparable effects in auditory and speech performance as children with non-ANSD SNHL.

Imaging and audiological features of children with cochlear nerve deficiency.

Objective: Cochlear nerve deficiency (CND) accounts for 10-19% of hearing loss in children; this study investigated the imaging and audiological features of 25 CND children. Methods: A total of 563 children with an unpassed automatic auditory brainstem response were diagnosed with hearing loss in our department between December 2018 and December 2021, of which, the imaging and audiological features of 25 children (25/563, 4.4%) diagnosed with a CND were reviewed. Results: Twenty-one (21/25, 84.0%) CND children had unilateral deafness, and 4 cases of bilateral deafness. All deaf ears were diagnosed as severe hearing loss due to an auditory brainstem response. CM waves were recorded in 8 cases and DPOAE in 3 cases, suggesting the audiological characteristics of auditory neuropathy spectrum disorders (ANSD). MRI results indicated 23 cases had small cochlear nerves and 2 cases had absent cochlear nerves. No genetic mutations were identified in the 25 CND children. Conclusions: Most CND children had unilateral hearing loss; therefore, high-resolution MRI imaging of the internal auditory canal should be performed to detect the auditory nerve in children with severe hearing loss. Some CND children had characteristics of ANSD.

Characterization of an induced pluripotent stem cell line (UMi040-A) bearing an auditory neuropathy spectrum disorder-associated variant in TMEM43

Hearing loss is one of the most common sensory disorders. TMEM43 is expressed in cochlear glia-like supporting cells (GLSs) and is known to be associated with late-onset auditory neuropathy spectrum disorder (ANSD) and progressive hearing loss. Here, we describe the derivation of an induced pluripotent stem cell (iPSC) line from a patient lymphoblastoid cell line (LCL) carrying a single heterozygous nonsense variant (p.Arg372Ter (c.1114C > T)) in TMEM43 that leads to a truncated protein lacking the 4th transmembrane domain. This cell line can serve as a tool for disease modelling and development of therapeutic approaches to restore inner ear function.

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

ObjectiveCharacteristics 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. MethodsChildren 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. ResultsMaternal 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. ConclusionsDifferences 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.

Novel Pathogenic Variants in PJVK, the Gene Encoding Pejvakin, in Subjects with Autosomal Recessive Non-Syndromic Hearing Impairment and Auditory Neuropathy Spectrum Disorder.

Pathogenic variants in the PJVK gene cause the DFNB59 type of autosomal recessive non-syndromic hearing impairment (AR-NSHI). Phenotypes are not homogeneous, as a few subjects show auditory neuropathy spectrum disorder (ANSD), while others show cochlear hearing loss. The numbers of reported cases and pathogenic variants are still small to establish accurate genotype-phenotype correlations. We investigated a cohort of 77 Spanish familial cases of AR-NSHI, in whom DFNB1 had been excluded, and a cohort of 84 simplex cases with isolated ANSD in whom OTOF variants had been excluded. All seven exons and exon-intron boundaries of the PJVK gene were sequenced. We report three novel DFNB59 cases, one from the AR-NSHI cohort and two from the ANSD cohort, with stable, severe to profound NSHI. Two of the subjects received unilateral cochlear implantation, with apparent good outcomes. Our study expands the spectrum of PJVK mutations, as we report four novel pathogenic variants: p.Leu224Arg, p.His294Ilefs*43, p.His294Asp and p.Phe317Serfs*20. We review the reported cases of DFNB59, summarize the clinical features of this rare subtype of AR-NSHI and discuss the involvement of PJVK in ANSD.

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

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. 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). 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. 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 issue of auditory neuropathy: from origins to the present

The issue of auditory neuropathy spectrum disorders (ANSD) has been in a focus of specialists attention for a relatively short time, but during this time a huge amount of scientific and practical knowledge about this hearing disorder has been accumulated. ANSD is a specific auditory deficit caused by dysfunction of periphery part of the auditory system, which may affect the inner hair cells, the spiral ganglion neurons and the auditory nerve, as well as the area of synaptic contact between them, while the outer hair cells, as a rule, remain intact. 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, electrophysiological data may not correlate with hearing level, the discrepancy between pure tone audiometry and speech discrimination is observed. ANSD prevalence, epidemiology, contemporary views on its etiology, including detailed information on hereditary forms of the disorder and its risk factors are considered in the review. The data on the basic rungs of the ANSD pathogenesis, which underlie the development of various forms of the disorder and mainly determine the rehabilitation approach, are presented. The detailed clinical and audiological characteristics of ANSD are presented; contemporary approach to ANSD diagnosis and rehabilitation, including indications for surgical treatment, are considered.

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.