Case Report: Auditory Neuropathy and Central Auditory Processing Deficits in a Neuro-Otological Case-Study of Infratentorial Superficial Siderosis.

Hearing and balance impairment are the most frequently reported features of infratentorial (classical) superficial siderosis (iSS). There are few comprehensive descriptions of audiovestibular function in iSS and therefore limited understanding of the affected segment(s) of the audiovestibular pathway. In addition, monitoring disease progression and response to treatment is challenging and currently mainly guided by subjective patient reports and magnetic resonance imaging.

Novel Mutation in AIFM1 Gene Associated with X-Linked Deafness in a Moroccan Family.

Introduction: Auditory neuropathy is a hearing disorder where outer hair cell function within the cochlea is normal, but inner hair cell and/or the auditory nerve function is disrupted. It is a heterogeneous disorder, which can have either congenital or acquired causes.

Methods: We found a disease-segregating mutation in the X-linked AIFM1 gene through whole-exome sequencing, encoding the apoptosis-inducing factor mitochondrion-associated 1.

Contrasting mechanisms for hidden hearing loss: Synaptopathy vs myelin defects.

Hidden hearing loss (HHL) is an auditory neuropathy characterized by normal hearing thresholds but reduced amplitudes of the sound-evoked auditory nerve compound action potential (CAP). In animal models, HHL can be caused by moderate noise exposure or aging, which induces loss of inner hair cell (IHC) synapses. In contrast, recent evidence has shown that transient loss of cochlear Schwann cells also causes permanent auditory deficits in mice with similarities to HHL.

Auditory Neuropathy Spectrum Disorder (ANSD)-Clinical Characteristics and Pathogenic Variant Analysis of Three Nonsyndromic Deafness Families.

Objective: To analyze the phenotypic features and pathogenic variants of three unrelated families presenting with nonsyndromic auditory neuropathy spectrum disorder (ANSD).

Methods: Three recruited families that were affected by congenital deafness were clinically evaluated, including a detailed family history and audiological and radiological examination. The peripheral blood of all patients and their parents was collected for DNA extraction, and then, the exonic and flanking regions were enriched and sequenced using targeted capture and high-throughput sequencing technology.

Hearing screening in neonates with hyperbilirubinemia.

Background: Hyperbilirubinemia is toxic to the auditory pathways and to the central nervous system, leaving sequelae such as hearing loss and encephalopathy. The damage to the auditory system occurs primarily within the brainstem and cranial nerve VIII, and manifests clinically as auditory neuropathy spectrum disorder.

Aim: to establish the relationship that exists between hyperbilirubinemia at birth as a risk factor of neonatal hearing loss in children born in ABOU-EL-REISH hospital.

Subcortical neural generators of the envelope-following response in sleeping children: A transfer function analysis.

Multiple auditory structures, from cochlea to cortex, phase-lock to the envelope of complex stimuli. The relative contributions of these structures to the human surface-recorded envelope-following response (EFR) are still uncertain. Identification of the active contributor(s) is complicated by the fact that even the simplest two-tone (f&f) stimulus, targeting its (f-f) envelope, evokes additional linear (f&f) and non-linear (2f-f) phase-locked components as well as a transient auditory brainstem response (ABR).

The association between consanguineous marriage and offspring with congenital hearing loss.

Background: Consanguinity is a commonly recognized practice among marriages in the Middle East and may lead to an increase in the prevalence of inherited disorders. Autosomal recessive deafness is the most common form of inherited congenital hearing loss (CHL).

Objectives: Determine the association of consanguineous marriages with congenital sensorineural hearing loss (SNHL) and auditory neuropathy.

Cortical Neurophysiologic Correlates of Auditory Threshold in Adults and Children With Normal Hearing and Auditory Neuropathy Spectrum Disorder.

Purpose Auditory threshold estimation using the auditory brainstem response or auditory steady state response is limited in some populations (e.g., individuals with auditory neuropathy spectrum disorder [ANSD] or those who have difficulty remaining still during testing and cannot tolerate general anesthetic).

The Many Faces of DFNB9: Relating Variants to Hearing Impairment.

The gene encodes otoferlin, a critical protein at the synapse of auditory sensory cells, the inner hair cells (IHCs). In the absence of otoferlin, signal transmission of IHCs fails due to impaired release of synaptic vesicles at the IHC synapse. Biallelic pathogenic and likely pathogenic variants in predominantly cause autosomal recessive profound prelingual deafness, DFNB9.

Case studies in neuroscience: cortical contributions to the frequency-following response depend on subcortical synchrony.

Frequency-following responses to musical notes spanning the octave 65-130 Hz were elicited in a person with auditory neuropathy, a disorder of subcortical neural synchrony, and a control subject. No phaselocked responses were observed in the person with auditory neuropathy. The control subject had robust responses synchronized to the fundamental frequency and its harmonics.

Protection of Cochlear Ribbon Synapses and Prevention of Hidden Hearing Loss.

In the auditory system, ribbon synapses are vesicle-associated structures located between inner hair cells (IHCs) and spiral ganglion neurons that are implicated in the modulation of trafficking and fusion of synaptic vesicles at the presynaptic terminals. Synapse loss may result in hearing loss and difficulties with understanding speech in a noisy environment. This phenomenon happens without permanent hearing loss; that is, the cochlear synaptopathy is "hidden.

Electrocochleography Observations in a Series of Cochlear Implant Electrode Tip Fold-Overs.

Objective: Tip fold-over is a rare but serious complication of cochlear implant (CI) surgery. The purpose of this study was to present intraoperative electrocochleography (ECochG) observations in a series of CI electrode tip fold-overs.

Patients: Five pediatric subjects undergoing CI surgery through a round window (RW) approach with a perimodiolar electrode array, who were diagnosed with either auditory neuropathy spectrum disorder or enlarged vestibular aqueduct.

Acoustical and Perceptual Analysis of Noise Reduction Strategies in Individuals With Auditory Neuropathy Spectrum Disorders.

Purpose The conventional amplification devices render minimal or no benefit at abating the speech perception problems of individuals with auditory neuropathy spectrum disorder (ANSD). This study was undertaken to evaluate the effect of noise reduction strategies (multiband spectral subtraction, Wiener-as, Karhunen-Loeve transform [Subspace], and ideal binary mask [IdBM] algorithm) on speech using speech perception measures and acoustic measure among individuals with ANSD. Method Two groups of participants (age: 17-43 years) were recruited in the study.

Access to the Apical Cochlear Modiolus for Possible Stem Cell-based and Gene Therapy of the Auditory Nerve.

Objective: Loss of spiral ganglion neurons (SGN) is permanent and responsible for a substantial number of patients suffering from hearing impairment. It can derive from the degeneration of SGNs due to the death of sensory hair cells as well as from auditory neuropathy. Utilizing stem cells to recover lost SGNs increasingly emerges as a possible therapeutic option, but access to human SGNs is difficult due to their protected location within the bony impacted cochlea.

EABR measurements during cochlear implantation in one-year-old, infant, child, adult, and elderly patients.

Background: Clinical application of electrically-evoked intracochlear auditory brainstem responses (eABRs) for evaluation of brainstem maturity or aging changes has not been well investigated.

Aim/objective: We compare the eV latencies of intraoperative eABR measurements in one-year-olds, infants, children, adults, and the elderly, with the goal of investigating the changes in the brainstem auditory pathway due to development and aging.

Materials And Methods: We studied 58 ears of 51 patients who underwent cochlear implantation between 2013 and 2019 using MED-EL's Concerto or Synchrony implants with Flex28 or Flex soft electrodes.

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.

Cochlear Implantation Outcomes in Post Synaptic Auditory Neuropathies: A Systematic Review and Narrative Synthesis.

To establish outcomes following cochlear implantation (CI) in patients with postsynaptic auditory neuropathy (AN). Systematic review and narrative synthesis. Databases searched: MEDLINE, PubMed, EMBASE, Web of Science, Cochrane Collection and ClinicalTrials.

Effect of Quiet and Noise on P300 Response in Individuals with Auditory Neuropathy Spectrum Disorder.

 Auditory neuropathy spectrum disorder (ANSD) is a clinical condition in which individuals have normal cochlear responses and abnormal neural responses. There is a lack of evidence in the literature regarding the neural discrimination skill in individuals with ANSD, especially when the signal is presented in the presence of noise.  The present study was performed with the aim to investigate auditory discrimination skill, in quiet and in the presence of noise, in individuals with ANSD and to compare the findings with normal-hearing individuals.

Audiovestibular neuropathy in an immunocompetent man with cryptococcal meningitis.

Introduction: Cryptococcus spp. is a fungus responsible for 600,000 deaths per year worldwide, mainly in immunosuppressed subjects. However, 20% of cases occur in immunocompetent subjects.

Rare Causes of Unilateral Sensorineural Hearing Loss in Adults: Our Experience.

Bilateral hearing loss is attributed to almost 50% of times with genetic etiology, while most unilateral sensorineural hearing loss (USNHL) are not attributable to it. Limited literature is available on epidemiology of USNHL. Etiology of USNHL is very diverse and vast, it ranges from as common as Meniere's disease to as rare as an electric shock injury.

New trends in the prevention of occupational noise-induced hearing loss.

Noise exposure during lifespan is one of the main causes of hearing loss. The highest risk of noise-induced hearing loss (NIHL) is related to exposures in the workplace, and affects about 7% of the population. Occupational NIHL is irreversible, thus its prevention must be considered a priority.

Etiological Work-up in Referrals From Neonatal Hearing Screening: 20 Years of Experience.

Background: Confirmation of permanent hearing loss in a newborn should be followed by a search for an underlying etiology because this may impact hearing loss management and counselling.

Methods: Retrospective chart review of all newborns seen at a tertiary referral center after referral from newborn hearing screening over a 20-year period. The changes in the diagnostic protocol over the years are outlined and the most recent protocol includes targeted next-generation sequencing using a panel for known hearing loss causing genes, in all cases of bilateral sensorineural hearing loss (SNHL).

Mitochondrial Dysfunction and Therapeutic Targets in Auditory Neuropathy.

Sensorineural hearing loss (SNHL) becomes an inevitable worldwide public health issue, and deafness treatment is urgently imperative; yet their current curative therapy is limited. Auditory neuropathies (AN) were proved to play a substantial role in SNHL recently, and spiral ganglion neuron (SGN) dysfunction is a dominant pathogenesis of AN. Auditory pathway is a high energy consumption system, and SGNs required sufficient mitochondria.

Flexible Real-Time Polymerase Chain Reaction-Based Platforms for Detecting Deafness Mutations in Koreans: A Proposed Guideline for the Etiologic Diagnosis of Auditory Neuropathy Spectrum Disorder.

Routine application of next-generation sequencing in clinical settings is often limited by time- and cost-prohibitive complex filtering steps. Despite the previously introduced genotyping kit that allows screening of the 11 major recurring variants of sensorineural hearing loss (SNHL) genes in the Korean population, the demand for phenotype- and variant-specific screening kits still remains. Herein, we developed a new real-time PCR-based kit (U-TOP™ HL Genotyping Kit Ver2), comprising six variants from two auditory neuropathy spectrum disorder (ANSD) genes ( and ) and five variants from three SNHL genes (, , and ), with a distinct auditory phenotype, making this the first genotyping kit dedicated to ANSD.