Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (121)

Search Parameters:
Keywords = auditory nerve

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
10 pages, 1034 KiB  
Article
Infratemporal Fossa Approach with Preservation of the Posterior Bony Wall of External Auditory Canal: Case Series and the Outcome
by Hye Ah Joo, Na-Kyum Park and Jong Woo Chung
J. Clin. Med. 2025, 14(15), 5294; https://doi.org/10.3390/jcm14155294 - 26 Jul 2025
Viewed by 347
Abstract
Objective: To evaluate the outcomes of a modified infratemporal fossa approach (ITFA) that preserves the posterior external auditory canal (EAC) in patients with tumors in the infratemporal fossa and skull base, focusing on postoperative hearing and facial nerve function. Methods: This retrospective study [...] Read more.
Objective: To evaluate the outcomes of a modified infratemporal fossa approach (ITFA) that preserves the posterior external auditory canal (EAC) in patients with tumors in the infratemporal fossa and skull base, focusing on postoperative hearing and facial nerve function. Methods: This retrospective study included nine patients who underwent ITFA with posterior EAC preservation for tumor removal while minimizing facial nerve rerouting. All surgeries were performed by a single surgeon. Preoperative and postoperative hearing levels, facial nerve function, tumor characteristics, and surgical outcomes were analyzed. Air-bone gaps (ABG) were assessed using pure tone audiometry, and facial nerve function was assessed using the House–Brackmann grading system. Results: The cohort consisted of eight female patients and one male patient, with a mean tumor size of 3.0 cm. Surgical outcomes were promising, with no statistically significant increase in postoperative ABG and well-preserved facial nerve function. Only one patient developed postoperative grade II facial palsy. A residual tumor was identified in one case with extensive meningioma, which has remained stable, and no recurrence or regrowth was noted during the follow-up period (mean: 3.7 years). The modified approach minimized complications related to conductive hearing loss and facial nerve dysfunction. Conclusions: The modified ITFA with posterior EAC preservation provides a promising alternative to conventional ITFA for managing deep-seated tumors. It preserves both hearing and facial nerve function while ensuring adequate tumor resection. Full article
(This article belongs to the Section Otolaryngology)
Show Figures

Figure 1

27 pages, 4853 KiB  
Review
Robotic Systems for Cochlear Implant Surgeries: A Review of Robotic Design and Clinical Outcomes
by Oneeba Ahmed, Mingfeng Wang, Bin Zhang, Richard Irving, Philip Begg and Xinli Du
Electronics 2025, 14(13), 2685; https://doi.org/10.3390/electronics14132685 - 2 Jul 2025
Viewed by 606
Abstract
Sensorineural hearing loss occurs when cochlear hair cells fail to convert mechanical sound waves into electrical signals transmitted via the auditory nerve. Cochlear implants (CIs) restore hearing by directly stimulating the auditory nerve with electrical impulses, often while preserving residual hearing. Over the [...] Read more.
Sensorineural hearing loss occurs when cochlear hair cells fail to convert mechanical sound waves into electrical signals transmitted via the auditory nerve. Cochlear implants (CIs) restore hearing by directly stimulating the auditory nerve with electrical impulses, often while preserving residual hearing. Over the past two decades, robotic-assisted techniques in otologic surgery have gained prominence for improving precision and safety. Robotic systems support critical procedures such as mastoidectomy, cochleostomy drilling, and electrode array (EA) insertion. These technologies aim to minimize trauma and enhance hearing preservation. Despite the outpatient nature of most CI surgeries, surgeons still face challenges, including anatomical complexity, imaging demands, and rising costs. Robotic systems help address these issues by streamlining workflows, reducing variability, and improving electrode placement accuracy. This review evaluates robotic systems developed for cochlear implantation, focusing on their design, surgical integration, and clinical outcomes. This review concludes that robotic systems offer low insertion speed, which leads to reduced insertion forces and lower intracochlear pressure. However, their impact on trauma, long-term hearing preservation, and speech outcome remains uncertain. Further research is needed to assess clinical durability, cost-effectiveness, and patient-reported outcomes. Full article
(This article belongs to the Special Issue Emerging Biomedical Electronics)
Show Figures

Figure 1

19 pages, 748 KiB  
Systematic Review
Kolliker’s Organ and Its Functional Role in the Development of Corti’s Organ and Auditory Systems
by Valeria Caragli, Valerio M. Di Pasquale Fiasca, Elisabetta Genovese and Alessandro Martini
Audiol. Res. 2025, 15(4), 75; https://doi.org/10.3390/audiolres15040075 - 23 Jun 2025
Cited by 1 | Viewed by 328
Abstract
Background: Kölliker’s organ (KO), a transient structure in the cochlea, plays a critical role in the auditory maturation of mammals, particularly during embryonic and early postnatal development. This organ is essential for the proper differentiation and function of cochlear cells, acting as [...] Read more.
Background: Kölliker’s organ (KO), a transient structure in the cochlea, plays a critical role in the auditory maturation of mammals, particularly during embryonic and early postnatal development. This organ is essential for the proper differentiation and function of cochlear cells, acting as a pivotal source of signalling molecules that influence hair cell development and synaptic connectivity. Methods: This study systematically analyses the literature according to the PRISMA statement in order to evaluate the function roles of KO during cochlea development, reporting the molecular mechanisms and signalling pathways involved. Results: From our study, it emerged that KO supporting cells release adenosine triphosphate (ATP) through connexin hemichannels, initiating a cascade of intracellular calcium (Ca2+) signalling in adjacent inner hair cells (IHCs). This signalling promotes the release of glutamate, facilitating synaptic excitation of afferent nerve fibres and enhancing auditory neuron maturation prior to the onset of hearing. Additionally, the spontaneous electrical activity generated within KO supports the establishment of essential neural connections in the auditory pathway. The dynamic interplay between ATP release, Ca2+ signalling, and morphological changes in KO is crucial for cochlear compartmentalisation and fluid regulation, contributing to the formation of endolymph and perilymph. Furthermore, KO supports cellular plasticity and may provide a reservoir of precursor cells capable of trans-differentiating into hair cells under specific conditions. Conclusions: Dysregulation of KO function or delayed degeneration of its supporting cells has been implicated in auditory disorders, underscoring the importance of this organ in normal cochlear development and auditory function. Despite its identification over a century ago, further investigation is necessary to elucidate the molecular mechanisms underlying KO’s contributions to auditory maturation, particularly in human physiology. Full article
Show Figures

Figure 1

22 pages, 4121 KiB  
Article
An Integrated Spatial-Spectral Denoising Framework for Robust Electrically Evoked Compound Action Potential Enhancement and Auditory Parameter Estimation
by Fan-Jie Kung
Sensors 2025, 25(11), 3523; https://doi.org/10.3390/s25113523 - 3 Jun 2025
Viewed by 384
Abstract
The electrically evoked compound action potential (ECAP) is a crucial physiological signal used by clinicians to evaluate auditory nerve functionality. Clean ECAP recordings help to accurately estimate auditory neural activity patterns and ECAP magnitudes, particularly through the panoramic ECAP (PECAP) framework. However, noise—especially [...] Read more.
The electrically evoked compound action potential (ECAP) is a crucial physiological signal used by clinicians to evaluate auditory nerve functionality. Clean ECAP recordings help to accurately estimate auditory neural activity patterns and ECAP magnitudes, particularly through the panoramic ECAP (PECAP) framework. However, noise—especially in low-signal-to-noise ratio (SNR) conditions—can lead to significant errors in parameter estimation. This study proposes a two-stage preprocessing denoising (TSPD) algorithm to address this issue and enhance ECAP signals. First, an ECAP matrix is constructed using the forward-masking technique, representing the signal as a two-dimensional image. This matrix undergoes spatial noise reduction via an improved spatial median (I-Median) filter. In the second stage, the denoised matrix is vectorized and further processed using a log-spectral amplitude (LSA) Wiener filter for spectral domain denoising. The enhanced vector is then reconstructed into the ECAP matrix for parameter estimation using PECAP. The above integrated spatial-spectral denoising framework is denoted as PECAP-TSPD in this work. Evaluations are conducted using a simulation-based ECAP model mixed with simulated and experimental noise, designed to emulate the spatial characteristics of real ECAPs. Three objective quality measures—namely, normalized root mean square error (RMSE), two-dimensional correlation coefficient (TDCC), and structural similarity index (SSIM)—are used. Simulated and experimental results show that the proposed PECAP-TSPD method has the lowest average RMSE of PECAP magnitudes (1.952%) and auditory neural patterns (1.407%), highest average TDCC (0.9988), and average SSIM (0.9931) compared to PECAP (6.446%, 5.703%, 0.9859, 0.8997), PECAP with convolutional neural network (CNN)-based denoising mask (PECAP-CNN) (9.700%, 7.111%, 0.9766, 0.8832), and PECAP with improved median filtering (PECAP-I-Median) (4.515%, 3.321%, 0.9949, 0.9470) under impulse noise conditions. Full article
(This article belongs to the Section Intelligent Sensors)
Show Figures

Graphical abstract

14 pages, 392 KiB  
Review
Noise-Induced Hearing Loss: Overview and Future Prospects for Research on Oxidative Stress
by Tsubasa Kitama, Takanori Nishiyama, Makoto Hosoya, Marie N. Shimanuki, Masafumi Ueno, Fukka You, Hiroyuki Ozawa and Naoki Oishi
Int. J. Mol. Sci. 2025, 26(10), 4927; https://doi.org/10.3390/ijms26104927 - 21 May 2025
Viewed by 1462
Abstract
Noise-induced hearing loss (NIHL) is a common type of sensorineural hearing loss caused by exposure to high-intensity noise that leads to irreversible cochlear damage. Despite extensive research on cochlear pathophysiology, the precise mechanisms remain unclear, and no established treatment exists. This is due [...] Read more.
Noise-induced hearing loss (NIHL) is a common type of sensorineural hearing loss caused by exposure to high-intensity noise that leads to irreversible cochlear damage. Despite extensive research on cochlear pathophysiology, the precise mechanisms remain unclear, and no established treatment exists. This is due to the challenges in imaging and the inability to perform biopsies in human patients. Consequently, animal models, particularly mice, have been widely used to study NIHL. Clinically, NIHL presents as either a temporary threshold shift, in which hearing recovers, or a permanent threshold shift, which results in an irreversible loss. Histopathological studies have identified the key features of NIHL, including outer hair cell loss, auditory nerve degeneration, and synaptic impairment. Recent findings suggest that oxidative stress and inflammation are major contributors to NIHL, highlighting the potential for therapeutic interventions, such as antioxidants and anti-inflammatory agents. Given the increasing prevalence of NIHL owing to occupational noise exposure and personal audio device use, addressing this issue is a pressing public health challenge. This review summarizes the clinical features, underlying mechanisms, and emerging treatment strategies for NIHL while identifying current knowledge gaps and future research directions. Full article
(This article belongs to the Special Issue Oxidative Stress and Cell Damage)
Show Figures

Figure 1

8 pages, 1647 KiB  
Article
Intraoperative Assessment of Cochlear Nerve Function During Cochlear Implantation Using the Auditory Nerve Test Stimulator
by Karin Hallin and Nadine Schart-Morén
Audiol. Res. 2025, 15(2), 36; https://doi.org/10.3390/audiolres15020036 - 1 Apr 2025
Cited by 1 | Viewed by 661
Abstract
Background/Objectives: A crucial factor for a successful cochlear implant (CI) outcome is an intact auditory nerve (AN). The integrity of the AN can be tested during implantation by measuring electrical auditory brainstem responses (eABR) via the CI. A method that does not require [...] Read more.
Background/Objectives: A crucial factor for a successful cochlear implant (CI) outcome is an intact auditory nerve (AN). The integrity of the AN can be tested during implantation by measuring electrical auditory brainstem responses (eABR) via the CI. A method that does not require a CI is the use of the auditory nerve test stimulator (ANTS) from MED-EL (Innsbruck, Austria). The aim of the current study was to investigate the cases tested with the ANTS at our clinic and to describe the hearing results following CI for the cases who were implanted with a CI. Methods: All patients underwent preoperative magnetic resonance imaging (MRI) and high-resolution computed tomography (HRCT) to rule out cochlear malformation or retrocochlear pathology. In this study, we described all cases from when we began using the ANTS in 2011. Results: Five patients were tested intraoperatively: three adults with long-term deafness prior to CI and two children with no detectable AN. Three of the five patients were implanted with a CI. All implanted patients in this study could hear with their CIs, even though the speech perception results were limited. Conclusions: The ANTS can be used as a method to assess cochlear nerve function during implantation. The eABR results from the ANTS and the implanted CI were comparable for all cases in our study. Minor changes in waveform latencies were found between ANTS and CI stimulation and may be explained by the insertion depth of the electrode used for stimulation. Full article
(This article belongs to the Special Issue Innovations in Cochlear Implant Surgery)
Show Figures

Figure 1

49 pages, 2083 KiB  
Systematic Review
Pain and the Brain: A Systematic Review of Methods, EEG Biomarkers, Limitations, and Future Directions
by Bayan Ahmad and Buket D. Barkana
Neurol. Int. 2025, 17(4), 46; https://doi.org/10.3390/neurolint17040046 - 21 Mar 2025
Viewed by 2245
Abstract
Background: Pain is prevalent in almost all populations and may often hinder visual, auditory, tactile, olfactory, and taste perception as it alters brain neural processing. The quantitative methods emerging to define pain and assess its effects on neural functions and perception are important. [...] Read more.
Background: Pain is prevalent in almost all populations and may often hinder visual, auditory, tactile, olfactory, and taste perception as it alters brain neural processing. The quantitative methods emerging to define pain and assess its effects on neural functions and perception are important. Identifying pain biomarkers is one of the initial stages in developing such models and interventions. The existing literature has explored chronic and experimentally induced pain, leveraging electroencephalograms (EEGs) to identify biomarkers and employing various qualitative and quantitative approaches to measure pain. Objectives: This systematic review examines the methods, participant characteristics, types of pain states, associated pain biomarkers of the brain’s electrical activity, and limitations of current pain studies. The review identifies what experimental methods researchers implement to study human pain states compared to human control pain-free states, as well as the limitations in the current techniques of studying human pain states and future directions for research. Methods: The research questions were formed using the Population, Intervention, Comparison, Outcome (PICO) framework. A literature search was conducted using PubMed, PsycINFO, Embase, the Cochrane Library, IEEE Explore, Medline, Scopus, and Web of Science until December 2024, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines to obtain relevant studies. The inclusion criteria included studies that focused on pain states and EEG data reporting. The exclusion criteria included studies that used only MEG or fMRI neuroimaging techniques and those that did not focus on the evaluation or assessment of neural markers. Bias risk was determined by the Newcastle–Ottawa Scale. Target data were compared between studies to organize the findings among the reported results. Results: The initial search resulted in 592 articles. After exclusions, 24 studies were included in the review, 6 of which focused on chronic pain populations. Experimentally induced pain methods were identified as techniques that centered on tactile perception: thermal, electrical, mechanical, and chemical. Across both chronic and stimulated pain studies, pain was associated with decreased or slowing peak alpha frequency (PAF). In the chronic pain studies, beta power increases were seen with pain intensity. The functional connectivity and pain networks of chronic pain patients differ from those of healthy controls; this includes the processing of experimental pain. Reportedly small sample sizes, participant comorbidities such as neuropsychiatric disorders and peripheral nerve damage, and uncontrolled studies were the common drawbacks of the studies. Standardizing methods and establishing collaborations to collect open-access comprehensive longitudinal data were identified as necessary future directions to generalize neuro markers of pain. Conclusions: This review presents a variety of experimental setups, participant populations, pain stimulation methods, lack of standardized data analysis methods, supporting and contradicting study findings, limitations, and future directions. Comprehensive studies are needed to understand the pain and brain relationship deeper in order to confirm or disregard the existing findings and to generalize biomarkers across chronic and experimentally induced pain studies. This requires the implementation of larger, diverse cohorts in longitudinal study designs, establishment of procedural standards, and creation of repositories. Additional techniques include the utilization of machine learning and analyzing data from long-term wearable EEG systems. The review protocol is registered on INPLASY (# 202520040). Full article
Show Figures

Figure 1

20 pages, 1045 KiB  
Systematic Review
A Systematic Review: State of the Science on Diagnostics of Hidden Hearing Loss
by Sunil Shenoy, Khushi Bhatt, Yalda Yazdani, Helia Rahimian, Hamid R. Djalilian and Mehdi Abouzari
Diagnostics 2025, 15(6), 742; https://doi.org/10.3390/diagnostics15060742 - 16 Mar 2025
Viewed by 1370
Abstract
Background/Objectives: A sizeable population of patients with normal pure-tone audiograms endorse a consistent difficulty of following conversations in noisy environments. Termed hidden hearing loss (HHL), this condition evades traditional diagnostic methods for hearing loss and thus is significantly under-diagnosed and untreated. This [...] Read more.
Background/Objectives: A sizeable population of patients with normal pure-tone audiograms endorse a consistent difficulty of following conversations in noisy environments. Termed hidden hearing loss (HHL), this condition evades traditional diagnostic methods for hearing loss and thus is significantly under-diagnosed and untreated. This review sought to identify emerging methods of diagnosing HHL via measurement of its histopathologic correlate: cochlear synaptopathy, the loss of synapses in the auditory nerve pathway. Methods: A thorough literature search of multiple databases was conducted to identify studies with objective, electrophysiological measures of synaptopathy. The PRISMA protocol was employed to establish criteria for the selection of relevant literature. Results: A total of 21 studies were selected with diagnostic methods, including the auditory brainstem response (ABR), electrocochleography (EcochG), middle ear muscle reflex (MEMR), and frequency-following response (FFR). Measures that may indicate the presence of synaptopathy include a reduced wave I amplitude of ABR, reduced SP amplitude of EcochG, and abnormal MEMR, among other measurements. Behavioral measures were often performed alongside electrophysiological measures, the most common of which was the speech-in-noise assessment. Conclusions: ABR was the most common diagnostic method for assessing HHL. Though ABR, EcochG, and MEMR may be sensitive to measuring synaptopathy, more literature comparing these methods is necessary. A two-pronged approach combining behavioral and electrophysiological measures may prove useful as a criterion for diagnosing and estimating the extent of pathology in affected patients. Full article
(This article belongs to the Special Issue Pathology and Diagnosis of Head and Neck Diseases)
Show Figures

Figure 1

38 pages, 5006 KiB  
Article
Changes in the Proteomic Profile After Audiogenic Kindling in the Inferior Colliculus of the GASH/Sal Model of Epilepsy
by Laura Zeballos, Carlos García-Peral, Martín M. Ledesma, Jerónimo Auzmendi, Alberto Lazarowski and Dolores E. López
Int. J. Mol. Sci. 2025, 26(5), 2331; https://doi.org/10.3390/ijms26052331 - 5 Mar 2025
Viewed by 1303
Abstract
Epilepsy is a multifaceted neurological disorder characterized by recurrent seizures and associated with molecular and immune alterations in key brain regions. The GASH/Sal (Genetic Audiogenic Seizure Hamster, Salamanca), a genetic model for audiogenic epilepsy, provides a powerful tool to study seizure mechanisms and [...] Read more.
Epilepsy is a multifaceted neurological disorder characterized by recurrent seizures and associated with molecular and immune alterations in key brain regions. The GASH/Sal (Genetic Audiogenic Seizure Hamster, Salamanca), a genetic model for audiogenic epilepsy, provides a powerful tool to study seizure mechanisms and resistance in predisposed individuals. This study investigates the proteomic and immune responses triggered by audiogenic kindling in the inferior colliculus, comparing non-responder animals exhibiting reduced seizure severity following repeated stimulation versus GASH/Sal naïve hamsters. To assess auditory pathway functionality, Auditory Brainstem Responses (ABRs) were recorded, revealing reduced neuronal activity in the auditory nerve of non-responders, while central auditory processing remained unaffected. Cytokine profiling demonstrated increased levels of proinflammatory markers, including IL-1 alpha (Interleukin-1 alpha), IL-10 (Interleukin-10), and TGF-beta (Transforming Growth Factor beta), alongside decreased IGF-1 (Insulin-like Growth Factor 1) levels, highlighting systemic inflammation and its interplay with neuroprotection. Building on these findings, a proteomic analysis identified 159 differentially expressed proteins (DEPs). Additionally, bioinformatic approaches, including Gene Set Enrichment Analysis (GSEA) and Weighted Gene Co-expression Network Analysis (WGCNA), revealed disrupted pathways related to metabolic and inflammatory epileptic processes and a module potentially linked to a rise in the threshold of seizures, respectively. Differentially expressed genes, identified through bioinformatic and statistical analyses, were validated by RT-qPCR. This confirmed the upregulation of six genes (Gpc1—Glypican-1; Sdc3—Syndecan-3; Vgf—Nerve Growth Factor Inducible; Cpne5—Copine 5; Agap2—Arf-GAP with GTPase domain, ANK repeat, and PH domain-containing protein 2; and Dpp8—Dipeptidyl Peptidase 8) and the downregulation of two (Ralb—RAS-like proto-oncogene B—and S100b—S100 calcium-binding protein B), aligning with reduced seizure severity. This study may uncover key proteomic and immune mechanisms underlying seizure susceptibility, providing possible novel therapeutic targets for refractory epilepsy. Full article
(This article belongs to the Special Issue Neuroproteomics: Focus on Nervous System Function and Disease)
Show Figures

Figure 1

13 pages, 2936 KiB  
Article
Functional and Structural Changes in the Inner Ear and Cochlear Hair Cell Loss Induced by Hypergravity
by Jin Sil Choi, Kyu-Sung Kim and Hyun Ji Kim
Int. J. Mol. Sci. 2025, 26(2), 758; https://doi.org/10.3390/ijms26020758 - 17 Jan 2025
Viewed by 1316
Abstract
Gravitational changes have been shown to cause significant abnormalities in various body systems, including the cardiovascular, immune, vestibular, and musculoskeletal systems. While numerous studies have examined the response of the vestibular system to gravitational stimulation, research on functional changes in the peripheral inner [...] Read more.
Gravitational changes have been shown to cause significant abnormalities in various body systems, including the cardiovascular, immune, vestibular, and musculoskeletal systems. While numerous studies have examined the response of the vestibular system to gravitational stimulation, research on functional changes in the peripheral inner ear remains limited. The inner ear comprises two closely related structures: the vestibule and cochlea. These components share similar structures and neural functions, highlighting the importance of investigating changes in auditory nerve cells in response to gravitational alterations. To address this gap, we studied the functional and structural changes in the inner ear following exposure to hypergravity stimuli. Our findings demonstrate changes in auditory brainstem responses (ABRs) in the cochlea. ABR recordings were used to analyze click thresholds, as well as the amplitude and latency of tone bursts. The click thresholds at all frequencies increased in the group exposed to hypergravity in the long term. Additionally, tone burst results revealed significantly reduced amplitudes at high frequencies and delayed latencies in the hypergravity models. Notably, greater hair cell loss was observed in the middle and basal turns of the cochlea, indicating that mid and high-frequency regions are more vulnerable to hypergravity stimulation. Furthermore, nerve damage on the cochlear surface was evident in subjects exposed to 4G stimulation for 4 weeks. These findings suggest that the inner ear and its neural activity can be functionally and structurally affected by prolonged exposure to hypergravity. Full article
(This article belongs to the Section Molecular Biology)
Show Figures

Figure 1

13 pages, 1889 KiB  
Article
Normative Values of Brainstem Auditory-Evoked Responses in Sheep
by Katharina Suntinger, Adrian Dalbert, Lukas Prochazka, Milena Tegelkamp, Peter Kronen, Karina Klein, Christof Röösli, Alexander Huber and Flurin Pfiffner
Brain Sci. 2025, 15(1), 69; https://doi.org/10.3390/brainsci15010069 - 14 Jan 2025
Viewed by 1035
Abstract
Background: The brainstem auditory-evoked response (BAER) is an established electrophysiological measure of neural activity from the auditory nerve up to the brain stem. The BAER is used to diagnose abnormalities in auditory pathways and in neurophysiological human and animal research. However, normative data [...] Read more.
Background: The brainstem auditory-evoked response (BAER) is an established electrophysiological measure of neural activity from the auditory nerve up to the brain stem. The BAER is used to diagnose abnormalities in auditory pathways and in neurophysiological human and animal research. However, normative data for BAERs in sheep, which represent an adequate large animal model for translational and basic otological research, are lacking. Objective: The aim of this study was to assess the function of the ovine auditory nervous system by determining normative values for the BAER and to compare sheep with human BAER data. Methods: In this retrospective study, BAER data for click stimuli at a range of sound pressure levels (SPLs) were analyzed. A series of 15 samples from six sheep with a mean age of 41.8 months was included. Results: The mean BAER threshold was 45.3 dB SPL. At 100 dB SPL, the mean (±standard deviation, SD) latency of wave V was 4.35 (±0.18) ms, that of wave III was 2.44 (±0.15) ms, and that of wave I was 0.88 (±0.13) ms. At 100 dB SPL, the mean interpeak latency of waves I–III was 1.56 (±0.18) ms, that of waves III–V was 1.91 (±0.16) ms, and that of waves I–V was 3.47 (±0.20) ms. The mean amplitudes at 100 dB SPL were 0.04 (±0.03) µV for wave I, 0.50 (±0.24) µV for wave III, and 0.40 (±0.25) µV for wave V. Conclusions: The normative values for sheep BAERs were reproducible and similar to those of humans. The normative BAER values further support sheep as an adequate animal model for otological research. Full article
Show Figures

Figure 1

14 pages, 1518 KiB  
Article
Tympanic Pre-Operative Electrically Evoked Auditory Late Response (TympEALR) as an Alternative to Trans-Tympanic Tests Using Anesthesia in Cochlear Implant Candidacy
by Daniel Polterauer, Maike Neuling and Florian Simon
J. Clin. Med. 2024, 13(24), 7573; https://doi.org/10.3390/jcm13247573 - 12 Dec 2024
Viewed by 1165
Abstract
Background/Objectives: Before a cochlear implant is considered, patients undergo various audiological tests to assess their suitability. One key test measures the auditory brainstem response (ABR) to acoustic stimuli. However, in some cases, even with maximum sound stimulation, no response is detected. Methods [...] Read more.
Background/Objectives: Before a cochlear implant is considered, patients undergo various audiological tests to assess their suitability. One key test measures the auditory brainstem response (ABR) to acoustic stimuli. However, in some cases, even with maximum sound stimulation, no response is detected. Methods: The promontory test involves electrical stimulation near the auditory nerve, allowing patients to associate the sensation. Ideally, the electrode is placed in the middle ear after opening the eardrum. This method, along with trans-tympanic electrically evoked ABR in local anesthesia (LA-TT-EABR) and the cortical equivalent (LA-TT-EALR), helps assess the auditory nerve’s existence and excitability. The TympEALR test, utilizing a “tympanic LA-TT-EALR”, provides an alternative measurement. Previous research has shown the possibility of deriving brainstem and cortical potentials through trans-tympanic electrical stimulation, allowing for objective assessment of the auditory nerve’s integrity and potentially objectifying patient sensations. Results: Sixteen patients have been tested using TympEALR. In seven of these, we found a positive response. The morphology was similar to other electrically evoked cortical auditory responses (EALR), e.g., using cochlear implants or trans-tympanic stimulation electrodes. We observed a higher influence of electrical artifacts than in other EALRs. Conclusions: TympEALR showed positive results in nearly half of the study participants, potentially avoiding invasive procedures. TympEALR can be a valuable alternative to trans-tympanic methods. More research is needed to determine if a negative result suggests against cochlear implantation. Full article
(This article belongs to the Section Otolaryngology)
Show Figures

Figure 1

14 pages, 785 KiB  
Systematic Review
State-of-the-Art on the Impact of Bimodal Acoustic Stimulation on Speech Perception in Noise in Adults: A Systematic Review
by Antonio Casarella, Anna Notaro, Carla Laria, Nicola Serra, Elisabetta Genovese, Rita Malesci, Gennaro Auletta and Anna Rita Fetoni
Audiol. Res. 2024, 14(5), 914-927; https://doi.org/10.3390/audiolres14050077 - 16 Oct 2024
Cited by 1 | Viewed by 2211
Abstract
Background/Objectives: Bimodal stimulation (BS), which combines the use of a cochlear implant (CI) in one ear and a hearing aid (HA) in the opposite ear, is an established strategy to treat hearing loss by exploiting the unique capabilities of each device. CIs stimulate [...] Read more.
Background/Objectives: Bimodal stimulation (BS), which combines the use of a cochlear implant (CI) in one ear and a hearing aid (HA) in the opposite ear, is an established strategy to treat hearing loss by exploiting the unique capabilities of each device. CIs stimulate the auditory nerve by bypassing damaged hair cells, while HAs amplify sounds by requiring a functional hearing residual. The aim of this systematic review is to investigate the advantages and disadvantages of BS such as speech perception in noise. Methods: We examined clinical studies published from October 2020 to July 2024, following the PRISMA guidelines, focusing on the advantages and disadvantages of BS on speech perception in noise in adulthood. Results: BS in adult patients significantly improves speech perception in quiet and noisy environments, especially for those with increased residual hearing. Unilateral CIs and BS perform similarly in quiet conditions, but BS significantly improves speech discrimination in noisy environments if loudness between the two devices is appropriately balanced. Conclusions: Directional microphones and programming software are new technologies that succeed in reducing environmental noise and improving verbal perception outcomes, although their features in the literature are controversial. In addition, the individuals using BS may face temporal mismatches mainly due to differing device latencies, affecting sound localization. Compensating for these mismatches can enhance localization accuracy. However, modulated noise remains a significant obstacle to verbal perception in noise. Valuable assessment tools such as music tests provide further information on hearing performance and quality of life. More research is needed to define certain selection criteria. Full article
Show Figures

Figure 1

21 pages, 8172 KiB  
Article
Differentiation of Spiral Ganglion Neurons from Human Dental Pulp Stem Cells: A Further Step towards Autologous Auditory Nerve Recovery
by Yassine Messat, Marta Martin-Fernandez, Said Assou, Keshi Chung, Frederic Guérin, Csilla Gergely, Frederic Cuisinier and Azel Zine
Int. J. Mol. Sci. 2024, 25(16), 9115; https://doi.org/10.3390/ijms25169115 - 22 Aug 2024
Cited by 1 | Viewed by 1984
Abstract
The degeneration of spiral ganglion neurons (SGNs), which convey auditory signals from hair cells to the brain, can be a primary cause of sensorineural hearing loss (SNHL) or can occur secondary to hair cell loss. Emerging therapies for SNHL include the replacement of [...] Read more.
The degeneration of spiral ganglion neurons (SGNs), which convey auditory signals from hair cells to the brain, can be a primary cause of sensorineural hearing loss (SNHL) or can occur secondary to hair cell loss. Emerging therapies for SNHL include the replacement of damaged SGNs using stem cell-derived otic neuronal progenitors (ONPs). However, the availability of renewable, accessible, and patient-matched sources of human stem cells is a prerequisite for successful replacement of the auditory nerve. In this study, we derived ONP and SGN-like cells by a reliable and reproducible stepwise guidance differentiation procedure of self-renewing human dental pulp stem cells (hDPSCs). This in vitro differentiation protocol relies on the modulation of BMP and TGFβ pathways using a free-floating 3D neurosphere method, followed by differentiation on a Geltrex-coated surface using two culture paradigms to modulate the major factors and pathways involved in early otic neurogenesis. Gene and protein expression analyses revealed efficient induction of a comprehensive panel of known ONP and SGN-like cell markers during the time course of hDPSCs differentiation. Atomic force microscopy revealed that hDPSC-derived SGN-like cells exhibit similar nanomechanical properties as their in vivo SGN counterparts. Furthermore, spiral ganglion neurons from newborn rats come in close contact with hDPSC-derived ONPs 5 days after co-culturing. Our data demonstrate the capability of hDPSCs to generate SGN-like neurons with specific lineage marker expression, bipolar morphology, and the nanomechanical characteristics of SGNs, suggesting that the neurons could be used for next-generation cochlear implants and/or inner ear cell-based strategies for SNHL. Full article
(This article belongs to the Special Issue Hearing Loss: Molecular Biological Insights)
Show Figures

Figure 1

14 pages, 3650 KiB  
Article
Effects of Castanopsis echinocarpa on Sensorineural Hearing Loss via Neuronal Gene Regulation
by Isabel Rodriguez, Youn Hee Nam, Sung Woo Shin, Gyeong Jin Seo, Na Woo Kim, Wanlapa Nuankaew, Do Hoon Kim, Yu Hwa Park, Hwa Yeon Lee, Xi Hui Peng, Bin Na Hong and Tong Ho Kang
Nutrients 2024, 16(16), 2716; https://doi.org/10.3390/nu16162716 - 15 Aug 2024
Cited by 2 | Viewed by 1508
Abstract
Sensorineural hearing loss (SNHL), characterized by damage to the inner ear or auditory nerve, is a prevalent auditory disorder. This study explores the potential of Castanopsis echinocarpa (CAE) as a therapeutic agent for SNHL. In vivo experiments were conducted using zebrafish and mouse [...] Read more.
Sensorineural hearing loss (SNHL), characterized by damage to the inner ear or auditory nerve, is a prevalent auditory disorder. This study explores the potential of Castanopsis echinocarpa (CAE) as a therapeutic agent for SNHL. In vivo experiments were conducted using zebrafish and mouse models. Zebrafish with neomycin-induced ototoxicity were treated with CAE, resulting in otic hair cell protection with an EC50 of 0.49 µg/mL and a therapeutic index of 1020. CAE treatment improved auditory function and protected cochlear sensory cells in a mouse model after noise-induced hearing loss (NIHL). RNA sequencing of NIHL mouse cochleae revealed that CAE up-regulates genes involved in neurotransmitter synthesis, secretion, transport, and neuronal survival. Real-time qPCR validation showed that NIHL decreased the mRNA expression of genes related to neuronal function, such as Gabra1, Gad1, Slc32a1, CaMK2b, CaMKIV, and Slc17a7, while the CAE treatment significantly elevated these levels. In conclusion, our findings provide strong evidence that CAE protects against hearing loss by promoting sensory cell protection and enhancing the expression of genes critical for neuronal function and survival. Full article
(This article belongs to the Special Issue Effects of Plant Extracts on Human Health)
Show Figures

Figure 1

Back to TopTop