Auditory nerve

OBJECTIVE: This study focused on the intensities of cochlear implant (CI) stimulation in pediatric CI users with inner ear malformation or cochlear nerve deficiency (CND). In this population, CI programming is difficult because a large intensity of CI stimulation is required to achieve sufficient hearing, but the excess CI stimuli often induce facial nerve stimulation. We aimed to assess whether the results of intraoperative electrically evoked auditory brainstem responses (EABRs) testing predict maximum current levels of CI stimuli (cC levels) optimized by a behavioral-based method after long-term CI use...

Leptomeningeal carcinomatosis (LMC) from renal cell carcinoma (RCC) is rare. There is no established treatment strategy for LMC, and the prognosis is extremely poor. We describe a case of LMC from RCC treated with local CyberKnife radiotherapy (CKR) and systemic therapy with pazopanib. The patient was a 63-year-old man with brain metastases from right RCC. Surgery and CKR were performed for the brain metastases, and the lesions were subsequently controlled. The patient developed isolated lesions in the pituitary stalk, right internal auditory canal, left ventricular choroid plexus (CP), left facial nerve, and medulla oblongata after the surgery and CKR for brain metastases...

In mammalian hearing, type-I afferent auditory nerve fibers comprise the basis of the afferent auditory pathway. They are connected to inner hair cells of the cochlea via specialized ribbon synapses. Auditory nerve fibers of different physiological types differ subtly in their synaptic location and morphology. Low-spontaneous-rate auditory nerve fibers typically connect on the modiolar side of the inner hair cell, while high-spontaneous-rate fibers are typically found on the pillar side. In aging and noise-damaged ears, this fine-tuned balance between auditory nerve fiber populations can be disrupted and the functional consequences are currently unclear...

The locus coeruleus-norepinephrine system is thought to be involved in the clinical effects of vagus nerve stimulation. This system is known to prevent seizure development and induce long-term plastic changes, particularly with the release of norepinephrine in the hippocampus. However, the requisites to become responder to the therapy and the mechanisms of action are still under investigation. Using MRI, we assessed the structural and functional characteristics of the locus coeruleus and microstructural properties of locus coeruleus-hippocampus white matter tracts in patients with drug-resistant epilepsy responding or not to the therapy...

A 51-year-old man with a history of cisplatin treatment for a right testicular tumor underwent microvascular decompression for hemifacial spasm. At an early stage in the surgical procedure, the intraoperative auditory brainstem response (ABR) was diminished despite a relatively minimally invasive approach, resulting in irreversible hearing loss. Cisplatin is known to cause dose-dependent hearing impairment primarily affecting the cochlea, but it can also induce neurotoxicity. In the present case, prior cisplatin administration may have caused fragility of the cochlear nerve as well...

INTRODUCTION: The functional evaluation of auditory-nerve activity in spontaneous conditions has remained elusive in humans. In animals, the frequency analysis of the round-window electrical noise recorded by means of electrocochleography yields a frequency peak at around 900 to 1000 Hz, which has been proposed to reflect auditory-nerve spontaneous activity. Here, we studied the spectral components of the electrical noise obtained from cochlear implant electrocochleography in humans. METHODS: We recruited adult cochlear implant recipients from the Clinical Hospital of the Universidad de Chile, between the years 2021 and 2022...

This study assessed whether the effects of contralateral acoustic stimulation (CAS) are consistent with eliciting the medial olivocochlear (MOC) reflex for measurements sensitive to outer hair cell (otoacoustic emissions, OAEs), auditory-nerve (AN; compound action potential, CAP), and brainstem/cortical (envelope-following response, EFR) function. The effects of CAS were evaluated for simultaneous measurement of OAEs, CAPs, and EFRs in participants with normal hearing. Clicks were presented at 40 or 98 Hz in three ipsilateral noise conditions (no noise, 45 dB SPL, and 55 dB SPL)...

Non-invasive electrophysiological measures, such as auditory evoked potentials (AEPs), play a crucial role in diagnosing auditory pathology. However, the relationship between AEP morphology and cochlear degeneration remains complex and not well understood. Dau [J. Acoust. Soc. Am. 113, 936-950 (2003)] proposed a computational framework for modeling AEPs that utilized a nonlinear auditory-nerve (AN) model followed by a linear unitary response function. While the model captured some important features of the measured AEPs, it also exhibited several discrepancies in response patterns compared to the actual measurements...

Brown Vialetto Van Laere syndrome is a rare disorder characterized by progressive pontobulbar palsy with bilateral sensorineural hearing loss and lower cranial nerve palsies. Fifty-eight cases have been reported in the last hundred years. As the most common presenting complaint of this disorder is hearing loss, audiological evaluation plays a vital role in pointing towards and narrowing its diagnosis. We present a case report of a 12-year male child affected by this disorder.

Incomplete obliteration of the branchial apparatus results in the formation of branchial cleft anomalies. First branchial cleft anomalies may persist anywhere in the first branchial arch, from the external auditory canal at the level of the bony cartilaginous junction to the submandibular triangle. The majority of cases present in childhood as an opening in the skin though they may present as cysts or neck masses, mostly mistaken for neck abscesses which leads to inadequate treatment and complications. Here different cases of first branchial cleft anomalies with variable presentation and treatment are illustrated...

AIM: The aim was to study the radiological parameters using High Resolution Computed Tomography (HRCT) temporal bone to predict the Round Window Niche (RWN) visibility through the facial recess approach and to study radiological types of the round window niche. MATERIALS AND METHODS: Prospective study was done in the patients underwent CI surgery from 2019 to 2021. HRCT radiological parameters of the patients and their intraoperative visualisation from video recordings were compared to predict the most feasible parameters to predict good visualisation of RWN...

BACKGROUND: Cochlear implant surgeries are performed by different surgical routes, Round window (RW), Extended round window (Ext RW) and Cochleostomy (C). Optimum intracochlear electrode placement is important to achieve a successful outcome. Intra-operative electrophysiological testing (Impedance and ECAP) is crucial to assess the device function and appropriate electrode placement. The variability of portal of electrode insertion might affect the neural response and its characteristics...

BACKGROUND: Pure neuritic leprosy (PNL) is uncommon form of leprosy involving peripheral nerves. Some isolated case reports have shown imaging changes in the central nervous system (CNS) and also impairment in visual evoked potential (VEP), somatosensory evoked potential (SSEP) and brain stem auditory-evoked potentials (BAEPs) parameters in PNL, but there is lack of large study. This prospective observational study evaluates impairment in these central conduction studies among PNL patients...

Objective: This study aims to provide a comprehensive summary of the pathogenesis, screening modalities, treatment strategies, repair modalities and preliminary results associated with facial nerve tumors. Methods: A retrospective analysis was conducted on the clinical data of 12 patients with facial nerve tumors who were admitted to our department between May 2018 and February 2023. The study population consisted of 5 males and 7 females, with ages ranging from 35 to 90 years. Clinical symptoms observed in these patients included facial nerve palsy, hearing loss, tinnitus, headache, and otalgia, etc...

OBJECTIVE: Pediatric data regarding treatment via an auditory brainstem implant (ABI) remains sparse. The authors aimed to describe their experience at their institution and to delineate associated demographic data, audiometric outcomes, and surgical parameters. METHODS: An IRB-approved, retrospective chart review was conducted among the authors' pediatric patients who had undergone auditory brainstem implantation between 2012 and 2021. Demographic information including sex, age, race, coexisting syndrome(s), history of cochlear implant placement, average duration of implant use, and follow-up outcomes were collected...

INTRODUCTION: Auditory information is relayed from the cochlea via the eighth cranial nerve to the dorsal and ventral cochlear nuclei (DCN, VCN). The organization, neurochemistry and circuitry of the cochlear nuclei (CN) have been studied in many species. It is well-established that glycine is an inhibitory transmitter in the CN of rodents and cats, with glycinergic cells in the DCN and VCN. There are, however, major differences in the laminar and cellular organization of the DCN between humans (and other primates) and rodents and cats...

Secondary trigeminal neuralgia (TN) is caused by identifiable diseases or lesions of the trigeminal nerve root, Gasserian ganglion and/or pons. TN is a neuropathic pain disorder characterized by electric shock-like or stabbing pain in the facial region, which can lead to impaired health-related quality of life. The present case report describes a rare case of secondary TN caused by trigeminal nerve metastases from lung adenocarcinoma, in which opioids provided symptomatic relief. The patient was a 46-year-old man with stage IV lung adenocarcinoma...

Natural behaviors are a coordinated symphony of motor acts that drive reafferent (self-induced) sensory activation. Individual sensors cannot disambiguate exafferent (externally induced) from reafferent sources. Nevertheless, animals readily differentiate between these sources of sensory signals to carry out adaptive behaviors through corollary discharge circuits (CDCs), which provide predictive motor signals from motor pathways to sensory processing and other motor pathways. Yet, how CDCs comprehensively integrate into the nervous system remains unexplored...

The disruption of the synaptic connection between the sensory inner hair cells (IHCs) and the auditory nerve fiber terminals of the type I spiral ganglion neurons (SGN) has been observed early in several auditory pathologies (e.g., noise-induced or ototoxic drug-induced or age-related hearing loss). It has been suggested that glutamate excitotoxicity may be an inciting element in the degenerative cascade observed in these pathological cochlear conditions. Moreover, oxidative damage induced by free hydroxyl radicals and nitric oxide may dramatically enhance cochlear damage induced by glutamate excitotoxicity...

Pure-tone audiograms often poorly predict elderly humans' ability to communicate in everyday complex acoustic scenes. Binaural processing is crucial for discriminating sound sources in such complex acoustic scenes. The compromised perception of communication signals presented above hearing threshold has been linked to both peripheral and central age-related changes in the auditory system. Investigating young and old Mongolian gerbils of both sexes, an established model for human hearing, we demonstrate age-related supra-threshold deficits in binaural hearing using behavioral, electrophysiological, anatomical and imaging methods...