Search Results (34)

Background/Objectives: The OPA1 gene encodes a dynamin-related GTPase essential for mitochondrial fusion. Variants in OPA1 are a major cause of autosomal dominant optic atrophy (DOA). A subset of DOA patients exhibits hearing loss, often manifesting as auditory neuropathy spectrum disorder (ANSD). In this study, we aimed to describe the frequency of OPA1-related hearing loss in a large cohort of patients with hearing loss and to explore the genotype–phenotype correlations and appropriate interventions. Methods: A total of 18,475 Japanese patients with hearing loss were recruited. Targeted massively parallel sequencing of 158 deafness-related genes was performed, and individuals with OPA1 variants were identified. Clinical data, including age of onset, audiological findings, and systemic features, were retrospectively reviewed. Results: Ten individuals from eight independent families carrying OPA1 variants were identified. Three variants were classified as pathogenic or likely pathogenic, while five were variants of uncertain significance. Hearing loss was typically post-lingual in onset and progressive, with predominantly mild-to-moderate severity. Missense variants tended to be associated with DOA-plus phenotypes and ANSD. Five patients obtained only limited benefit from hearing aids, whereas one patient who received a cochlear implant achieved good speech perception. Conclusions: OPA1 is a rare causative gene for hearing loss and is frequently associated with the ANSD phenotype. Affected individuals exhibited phenotypic heterogeneity, which may reflect incomplete penetrance or the influence of mitochondrial DNA-related factors. Full article

Diabetes is known to affect metabolic, vascular, and nervous systems, although its influence on auditory function in children remains poorly defined. Understanding this association is essential due to its implications for cognitive, language, and social development. Numerous studies have found that children with Type 1 Diabetes Mellitus (T1DM) exhibit higher hearing thresholds at high frequencies (4000–8000 Hz) and lower speech understanding scores compared to healthy controls. Poor glycemic control and longer disease duration are consistently associated with worse auditory outcomes. The proposed mechanisms include microangiopathy and diabetic neuropathy affecting the auditory pathway. Many affected children do not report noticeable auditory symptoms, indicating a risk of underdiagnosis. Early identification is crucial, as hearing difficulties in children may be related to underlying diabetic conditions and are likely associated with poor glycemic control. Regular audiometric screening should be incorporated into the routine care of pediatric diabetes patients to identify hearing deficits before they affect communication and cognitive development. Full article

Background: Bortezomib, a proteasome inhibitor used in multiple myeloma (MM), is associated with several adverse effects, most notably peripheral neuropathy. Ototoxicity, however, remains a rare and underrecognized complication. Case presentation: We report the case of a 74-year-old man with MM who developed sudden unilateral sensorineural hearing loss following subcutaneous bortezomib administration. Audiometry confirmed severe right-sided hearing loss. MRI of the internal auditory canal was normal. Given the absence of other ototoxic agents, bortezomib was identified as the likely causative drug. The patient was treated with intratympanic dexamethasone injections, achieving partial hearing recovery. Subsequent chemotherapy re-exposure triggered another hearing decline, which again improved after repeated intratympanic treatment. Conclusions: Bortezomib-related ototoxicity is a rare but potentially reversible adverse event. This case suggests that early intratympanic corticosteroid therapy may mitigate cochlear injury, allowing continuation of chemotherapy for patients responding well to bortezomib. Full article

Background/Objectives: Retrocochlear auditory dysfunctions (RADs), including auditory neuropathy (AN) and auditory processing disorders (APD), encompass disorders characterized by impaired auditory processing beyond the cochlea. This narrative review critically examines their distinguishing features, synthesizing recent advances in classification, pathophysiology, clinical presentation, and treatment. Methods: This narrative review involved a comprehensive literature search across major electronic databases (e.g., PubMed, Scopus) to identify and synthesize relevant studies on the classification, diagnosis, and management of AN and APD. The goal was to update the view on etiologies (genetic/non-genetic) and individualized rehabilitative strategies. Diagnosis relies on a comprehensive assessment, including behavioral, electrophysiological, and imaging tests. Rehabilitation is categorized into bottom-up and top-down approaches. Results: ANSD is defined by neural desynchronization with preserved outer hair cell function, resulting in abnormal auditory brainstem responses and poor speech discrimination. The etiologies (distal/proximal) influence the prognosis for interventions, particularly cochlear implants (CI). APD involves central processing deficits, often with normal peripheral hearing and heterogeneous symptoms affecting speech perception and localization. Rehabilitation is multidisciplinary, utilizing bottom-up strategies (e.g., auditory training, CI) and compensatory top-down approaches. Remote microphone systems are highly effective in improving the signal-to-noise ratio. Conclusions: Accurate diagnosis and personalized, multidisciplinary management are crucial for optimizing communication and quality of life. Evidence suggests that combined bottom-up and top-down interventions may yield superior outcomes. However, methodological heterogeneity limits the generalizability of protocols, highlighting the need for further targeted research. Full article

Background: This prospective pilot study included four participants with chronic visual impairment and assessed functional and electrophysiological recovery following visual evoked potential (VEP)-guided auditory biofeedback across diverse etiologies. Low vision affects more than two billion people worldwide and imposes a sustained personal and socioeconomic burden. Conventional rehabilitation emphasizes optical aids and environmental modification without directly stimulating the visual pathway. Emerging evidence indicates that auditory biofeedback based on real-time cortical activity can leverage adult neuroplasticity. Methods: Four men (mean age 58 ± 12 years) with chronic visual impairment attributable to occipital stroke, stage IV macular hole, end-stage open-angle glaucoma, or diabetic maculopathy completed ten 10-min monocular sessions with the Retimax Vision Trainer over three weeks (15 Hz pattern reversal, 90% contrast). Primary end points were best corrected visual acuity (BCVA, ETDRS letters) and P100 amplitude/latency. Fixation stability was recorded with MAIA microperimetry when feasible. A focused PubMed review (2010–2025) mapped current evidence and research gaps. Results: Median BCVA improved by seven letters (IQR 0–15); three of eight eyes gained ≥ 10 letters and none lost vision. Mean P100 amplitude increased from 1.0 ± 1.2 µV to 3.0 ± 1.1 µV, while latency shortened by 3.9 ms. Electrophysiological improvement paralleled behavioural gain irrespective of lesion site. No adverse events occurred. Conclusions: A concise course of VEP-guided auditory biofeedback produced concordant functional and neurophysiological gains across retinal, optic nerve, and cortical pathologies. These pilot data support integration of closed-loop biofeedback into routine low vision care and justify larger sham-controlled trials. Full article

Transmembrane protein 43 (TMEM43 or LUMA) encodes a highly conserved protein found in the nuclear and endoplasmic reticulum membranes of many cell types and the intercalated discs and adherens junctions of cardiac myocytes. TMEM43 is involved in facilitating intra/extracellular signal transduction to the nucleus via the linker of the nucleoskeleton and cytoskeleton complex. Genetic mutations may result in reduced TMEM43 expression and altered TMEM43 protein cellular localization, resulting in impaired cell polarization, intracellular force transmission, and cell–cell connections. The p.S358L mutation causes arrhythmogenic right ventricular cardiomyopathy type-5 and is associated with increased absorption of lipids, fatty acids, and cholesterol in the mouse small intestine, which may promote fibro-fatty replacement of cardiac myocytes. Mutations (p.E85K and p.I91V) have been identified in patients with Emery–Dreifuss Muscular Dystrophy-related myopathies. Other mutations also lead to auditory neuropathy spectrum disorder-associated hearing loss and have a negative association with cancer progression and tumor cell survival. This review explores the pathogenesis of TMEM43 mutation-associated diseases in humans, highlighting animal and in vitro studies that describe the molecular details of disease processes and clinical, histologic, and molecular manifestations. Additionally, we discuss TMEM43 expression-related conditions and how each disease may progress to severe and life-threatening states. Full article

Background: Primary ciliary dyskinesia (PCD) is a rare hereditary disorder caused by defective motile cilia, predominantly affecting the respiratory system. Conductive hearing loss (CHL) due to chronic otitis media with effusion (OME) is a typical feature of PCD, particularly in childhood. However, the underlying mechanisms contributing to sensorineural hearing loss (SNHL) in patients with PCD remain unclear. Methods: We present the case of a 52-year-old male with a clinical diagnosis of PCD, confirmed by the presence of situs inversus, chronic respiratory symptoms, and ultrastructural ciliary defects. Results: Despite a history of recurrent acute otitis media (AOM), the patient developed severe bilateral SNHL, a relatively uncommon and poorly understood manifestation of PCD. Genetic testing revealed a pathogenic SH3TC2 variant, a gene classically associated with Charcot–Marie–Tooth disease type 4C (CMT4C), raising the possibility of an alternative or contributory genetic etiology for the patient’s auditory dysfunction. Conclusions: This case highlights the importance of comprehensive audiological and genetic evaluations in PCD patients, particularly those presenting with progressive or atypical HL. The presence of a pathogenic SH3TC2 mutation suggests a potential neuropathic component to the patient’s HL, underscoring the need for further research into the intersection between ciliary dysfunction and genetic neuropathies. Early identification and intervention are critical to optimizing auditory outcomes and quality of life in affected individuals. Full article

Repulsive guidance molecule-a (RGMa) has emerged as a significant therapeutic target in a variety of neurological disorders, including neurodegenerative diseases and acute conditions. This review comprehensively examines the multifaceted role of RGMa in central nervous system (CNS) pathologies such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, multiple sclerosis, neuromyelitis optica spectrum disorder, spinal cord injury, stroke, vascular dementia, auditory neuropathy, and epilepsy. The mechanisms through which RGMa contributes to neuroinflammation, neuronal degeneration, and impaired axonal regeneration are herein discussed. Evidence from preclinical studies associate RGMa overexpression with negative outcomes, such as increased neuroinflammation and synaptic loss, while RGMa inhibition, particularly the use of agents like elezanumab, has shown promise in enhancing neuronal survival and functional recovery. RGMa’s responses concerning immunomodulation and neurogenesis highlight its potential as a therapeutic avenue. We emphasize RGMa’s critical role in CNS pathology and its potential to pave the way for innovative treatment strategies in neurological disorders. While preclinical findings are encouraging so far, further clinical trials are needed to validate the safety and efficacy of RGMa-targeted therapies. Full article

Background/Objectives: The OTOF gene is reported to be the causative gene for non-syndromic recessive sensorineural hearing loss and auditory neuropathy spectrum disorder. About 300 variants have been reported, but there have been no reports to date on copy gain variants. Methods: We identified a copy gain variant in the OTOF gene through short-read next-generation sequencing analysis from one patient with auditory neuropathy. We also performed long-read next-generation sequencing analysis using the Oxford Nanopore Technologies adaptive sampling procedure. Results: The four-year-old male carried a duplication of chr2: 26,477,852 to 26,483,106 (a 5254-base duplication including exon 14 to exon 18 of the OTOF gene NM_001287489) and a c.5385C>A single nucleotide variant. We also confirmed that these two variants were located in the trans configuration based on haplotype phasing results using the long-read next-generation sequencing data. Conclusions: This is the first report of an auditory neuropathy patient with a large duplication variant in the OTOF gene. The identified variants were novel, but based on the clinical phenotype of the patient, these variants seem to be the genetic cause of this patient’s phenotype. Oxford Nanopore Technologies adaptive sampling is a powerful tool for the analysis of structural variants (particularly for determining the breakpoint and direction) and haplotype phasing. Full article

Auditory neuropathy spectrum disorder (ANSD) is often missed by standard hearing tests, accounting for up to 10% of hearing impairments (HI) and commonly linked to variants in 23 genes. We assessed 122 children with HI, including 102 with sensorineural hearing loss (SNHL) and 20 with ANSD. SNHL patients were genotyped for common GJB2 variants using qPCR, while ANSD patients underwent whole exome sequencing, with variants analyzed across 249 genes. Homozygous GJB2 variants were found in 54.9% of SNHL patients. In 60% of ANSD patients, variants were detected in OTOF (25%), CDH23, TMC1, COL11A1, PRPS1, TWNK, and HOMER2 genes, including eight novel variants. Transient evoked otoacoustic emissions testing revealed differences at 4000 Hz (p = 0.0084) between the ANSD and SNHL groups. The auditory steady-state response (ASSR) test showed significant differences at 500 Hz (p = 2.69 × 10⁻⁴) and 1000 Hz (p = 0.0255) compared to pure-tone audiometry (PTA) in ANSD patients. Our questionnaire shows that the parents of children with SNHL often report an improved quality of life with hearing aids or cochlear implants, while parents of children with ANSD frequently experience uncertainty about outcomes (p = 0.0026), leading to lower satisfaction. Full article

Background: Progressive auditory dysfunction is common in patients with generalized neurodegenerative conditions, but clinicians currently lack the diagnostic tools to determine the location/degree of the pathology and, hence, to provide appropriate intervention. In this study, we present the white-matter microstructure measurements derived from a novel diffusion-weighted magnetic resonance imaging (dMRI) technique in a patient with axonal auditory neuropathy and consider the findings in relation to the auditory intervention outcomes. Methods: We tracked the hearing changes in an adolescent with Riboflavin Transporter Deficiency (Type 2), evaluating the sound detection/discrimination, auditory evoked potentials, and both structural- and diffusion-weighted MRI findings over a 3-year period. In addition, we explored the effect of bilateral cochlear implantation in this individual. Results: Between the ages of 15 years and 18 years, the patient showed a complete loss of functional hearing ability. The auditory brainstem response testing indicated an auditory neuropathy with evidence of normal cochlear function but disrupted auditory neural activity. While three structural MRI assessments across this period showed a clinically normal cochleovestibular anatomy, the dMRI evaluation revealed a significant loss of fiber density consistent with axonopathy. The subsequent cochlear implant function was affected with the high levels of current required to elicit auditory sensations and concomitant vestibular and facial nerve stimulation issues. Conclusions: The case study demonstrates the ability of dMRI technologies to identify the subtle white-matter microstructure changes in the auditory pathway, which may disrupt the neural function in patients with auditory axonopathy. Full article

Background: Auditory neuropathy (AN) is a hearing disorder that affects neural activity in the VIIIth cranial nerve and central auditory pathways. Progressive forms have been reported in a number of neurodegenerative diseases and may occur as a result of both the deafferentiation and desynchronisation of neuronal processes. The purpose of this study was to describe changes in auditory function over time in a patient with axonal neuropathy and to explore the effect of auditory intervention. Methods: We tracked auditory function in a child with progressive AN associated with Charcot–Marie–Tooth (Type 2C) disease, evaluating hearing levels, auditory-evoked potentials, and perceptual abilities over a 3-year period. Furthermore, we explored the effect of auditory intervention on everyday listening and neuroplastic development. Results: While sound detection thresholds remained constant throughout, both electrophysiologic and behavioural evidence suggested auditory neural degeneration over the course of the study. Auditory brainstem response amplitudes were reduced, and perception of auditory timing cues worsened over time. Functional hearing ability (speech perception in noise) also deteriorated through the first 1.5 years of study until the child was fitted with a “remote-microphone” listening device, which subsequently improved binaural processing and restored speech perception ability to normal levels. Conclusions: Despite the deterioration of auditory neural function consistent with peripheral axonopathy, sustained experience with the remote-microphone listening system appeared to produce neuroplastic changes, which improved the patient’s everyday listening ability—even when not wearing the device. Full article

Auditory neuropathy spectrum disorder (ANSD) associated with mutations of the OTOF gene is one of the common types of sensorineural hearing loss of a hereditary nature. Due to its high genetic heterogeneity, ANSD is considered one of the most difficult hearing disorders to diagnose. The dataset from 270 known annotated single amino acid substitutions (SAV) related to ANSD was created. It was used to estimate the accuracy of pathogenicity prediction using the known (from dbNSFP4.4) method and a new one. The new method (ConStruct) for the creation of the protein-centric classification model is based on the use of Random Forest for the analysis of missense variants in exons of the OTOF gene. A system of predictor variables was developed based on the modern understanding of the structure and function of the otoferlin protein and reflecting the location of changes in the tertiary structure of the protein due to mutations in the OTOF gene. The conservation values of nucleotide substitutions in genomes of 100 vertebrates and 30 primates were also used as variables. The average prediction of balanced accuracy and the AUC value calculated by the 5-fold cross-validation procedure were 0.866 and 0.903, respectively. The model shows good results for interpreting data from the targeted sequencing of the OTOF gene and can be implemented as an auxiliary tool for the diagnosis of ANSD in the early stages of ontogenesis. The created model, together with the results of the pathogenicity prediction of SAVs via other known accurate methods, were used for the evaluation of a manually created set of 1302 VUS related to ANSD. Based on the analysis of predicted results, 16 SAVs were selected as the new most probable pathogenic variants. Full article

Prematurity is one of the most crucial risk factors negatively affecting the maturation of the auditory system. Children born preterm demonstrate high rates of hearing impairments. Auditory processing difficulties in preterm children might be a result of disturbances in the central auditory system development and/or sensory deprivation due to peripheral hearing loss. To investigate auditory processing in preterm children, we utilized a set of psychoacoustic tests to assess temporal processing and speech intelligibility. A total of 241 children aged 6–11 years old (136 born preterm and 105 healthy full-term children forming the control group) were assessed. The preterm children were divided into three groups based on their peripheral hearing status: 74 normal hearing (NH group); 30 children with bilateral permanent sensorineural hearing loss (SNHL group) and 32 children with bilateral auditory neuropathy spectrum disorder (ANSD group). The results showed significantly worse performance in all tests in premature children compared with full-term children. NH and SNHL groups showed significant age-related improvement in speech recognition thresholds in noise that might signify a “bottom-up” auditory processing maturation effect. Overall, all premature children had signs of auditory processing disorders of varying degrees. Analyzing and understanding the auditory processing specificity in preterm children can positively contribute to the more effective implementation of rehabilitation programs. Full article

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