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Couth S, Prendergast G, Guest H, Munro KJ, Moore DR, Plack CJ, Ginsborg J, Dawes P. A longitudinal study investigating the effects of noise exposure on behavioural, electrophysiological and self-report measures of hearing in musicians with normal audiometric thresholds. Hear Res 2024; 451:109077. [PMID: 39084132 DOI: 10.1016/j.heares.2024.109077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 06/07/2024] [Accepted: 07/08/2024] [Indexed: 08/02/2024]
Abstract
Musicians are at risk of hearing loss and tinnitus due to regular exposure to high levels of noise. This level of risk may have been underestimated previously since damage to the auditory system, such as cochlear synaptopathy, may not be easily detectable using standard clinical measures. Most previous research investigating hearing loss in musicians has involved cross-sectional study designs that may capture only a snapshot of hearing health in relation to noise exposure. The aim of this study was to investigate the effects of cumulative noise exposure on behavioural, electrophysiological, and self-report indices of hearing damage in early-career musicians and non-musicians with normal hearing over a 2-year period. Participants completed an annual test battery consisting of pure tone audiometry, extended high-frequency hearing thresholds, distortion product otoacoustic emissions (DPOAEs), speech perception in noise, auditory brainstem responses, and self-report measures of tinnitus, hyperacusis, and hearing in background noise. Participants also completed the Noise Exposure Structured Interview to estimate cumulative noise exposure across the study period. Linear mixed models assessed changes over time. The longitudinal analysis comprised 64 early-career musicians (female n = 34; age range at T0 = 18-26 years) and 30 non-musicians (female n = 20; age range at T0 = 18-27 years). There were few longitudinal changes as a result of musicianship. Small improvements over time in some measures may be attributable to a practice/test-retest effect. Some measures (e.g., DPOAE indices of outer hair cell function) were associated with noise exposure at each time point, but did not show a significant change over time. A small proportion of participants reported a worsening of their tinnitus symptoms, which participants attributed to noise exposure, or not using hearing protection. Future longitudinal studies should attempt to capture the effects of noise exposure over a longer period, taken at several time points, for a precise measure of how hearing changes over time. Hearing conservation programmes for "at risk" individuals should closely monitor DPOAEs to detect early signs of noise-induced hearing loss when audiometric thresholds are clinically normal.
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Affiliation(s)
- Samuel Couth
- Manchester Centre for Audiology and Deafness, University of Manchester, UK.
| | | | - Hannah Guest
- Manchester Centre for Audiology and Deafness, University of Manchester, UK
| | - Kevin J Munro
- Manchester Centre for Audiology and Deafness, University of Manchester, UK; Manchester Academic Health Science Centre, Manchester University Hospitals NHS Foundation Trust, UK
| | - David R Moore
- Manchester Centre for Audiology and Deafness, University of Manchester, UK; Communication Sciences Research Center, Cincinnati Children's Hospital Medical Centre, OH, USA
| | - Christopher J Plack
- Manchester Centre for Audiology and Deafness, University of Manchester, UK; Department of Psychology, Lancaster University, UK
| | | | - Piers Dawes
- Manchester Centre for Audiology and Deafness, University of Manchester, UK; Centre for Hearing Research, School of Health and Rehabilitation Sciences, University of Queensland, Australia
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Mittal R, Keith G, Lacey M, Lemos JRN, Mittal J, Assayed A, Hirani K. Diabetes mellitus, hearing loss, and therapeutic interventions: A systematic review of insights from preclinical animal models. PLoS One 2024; 19:e0305617. [PMID: 38985787 PMCID: PMC11236185 DOI: 10.1371/journal.pone.0305617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 06/02/2024] [Indexed: 07/12/2024] Open
Abstract
OBJECTIVES The aim of this systematic review article is to evaluate the relationship between diabetes mellitus (DM) and sensorineural hearing loss (SNHL) utilizing preclinical animal models. The review focused on studies assessing SNHL in diabetic animal models, elucidating the mechanisms of DM-associated SNHL, and exploring the response of diabetic animal models to noise overexposure. We also discussed studies investigating the efficacy of potential therapeutic strategies for amelioration of DM-associated SNHL in the animal models. METHODS A protocol of this systematic review was designed a priori and was registered in the PROSPERO database (registration number: CRD42023439961). We conducted a comprehensive search on PubMed, Science Direct, Web of Science, Scopus, and EMBASE databases. A minimum of three reviewers independently screened, selected, and extracted data. The risk of bias assessment of eligible studies was conducted using the Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) tool. RESULTS Following the screening of 238 studies, twelve original articles were included in this systematic review. The studies revealed that hyperglycemia significantly affects auditory function, with various pathological mechanisms contributing to DM-induced hearing impairment, including cochlear synaptopathy, microangiopathy, neuropathy, oxidative stress, mitochondrial abnormalities, and apoptosis-mediated cell death. Emerging interventions, such as Asiaticoside, Trigonelline, Chlorogenic acid, and Huotanquyu granules, demonstrated efficacy in providing otoprotection for preserving cochlear hair cells and hearing function. CONCLUSIONS Our systematic review delves into the intricate relationship between DM and hearing impairment in animal models. Future research should focus on targeted therapies to enhance cochlear mitochondrial function, alleviate oxidative stress, and regulate apoptosis. The association between SNHL and social isolation as well as cognitive decline underscores the necessity for innovative therapeutic modalities addressing yet undiscovered mechanisms. Translating findings from animal models to human studies will validate these findings, offering a synergistic approach to effectively manage DM-associated co-morbidities such as hearing impairment.
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Affiliation(s)
- Rahul Mittal
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Grant Keith
- School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Mitchel Lacey
- Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, United States of America
| | - Joana R. N. Lemos
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Jeenu Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Amro Assayed
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Khemraj Hirani
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, Florida, United States of America
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Temboury-Gutierrez M, Märcher-Rørsted J, Bille M, Yde J, Encina-Llamas G, Hjortkjær J, Dau T. Electrocochleographic frequency-following responses as a potential marker of age-related cochlear neural degeneration. Hear Res 2024; 446:109005. [PMID: 38598943 DOI: 10.1016/j.heares.2024.109005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 03/19/2024] [Accepted: 04/01/2024] [Indexed: 04/12/2024]
Abstract
Auditory nerve (AN) fibers that innervate inner hair cells in the cochlea degenerate with advancing age. It has been proposed that age-related reductions in brainstem frequency-following responses (FFR) to the carrier of low-frequency, high-intensity pure tones may partially reflect this neural loss in the cochlea (Märcher-Rørsted et al., 2022). If the loss of AN fibers is the primary factor contributing to age-related changes in the brainstem FFR, then the FFR could serve as an indicator of cochlear neural degeneration. In this study, we employed electrocochleography (ECochG) to investigate the effects of age on frequency-following neurophonic potentials, i.e., neural responses phase-locked to the carrier frequency of the tone stimulus. We compared these findings to the brainstem-generated FFRs obtained simultaneously using the same stimulation. We conducted recordings in young and older individuals with normal hearing. Responses to pure tones (250 ms, 516 and 1086 Hz, 85 dB SPL) and clicks were recorded using both ECochG at the tympanic membrane and traditional scalp electroencephalographic (EEG) recordings of the FFR. Distortion product otoacoustic emissions (DPOAE) were also collected. In the ECochG recordings, sustained AN neurophonic (ANN) responses to tonal stimulation, as well as the click-evoked compound action potential (CAP) of the AN, were significantly reduced in the older listeners compared to young controls, despite normal audiometric thresholds. In the EEG recordings, brainstem FFRs to the same tone stimulation were also diminished in the older participants. Unlike the reduced AN CAP response, the transient-evoked wave-V remained unaffected. These findings could indicate that a decreased number of AN fibers contributes to the response in the older participants. The results suggest that the scalp-recorded FFR, as opposed to the clinical standard wave-V of the auditory brainstem response, may serve as a more reliable indicator of age-related cochlear neural degeneration.
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Affiliation(s)
- Miguel Temboury-Gutierrez
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark.
| | - Jonatan Märcher-Rørsted
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark
| | - Michael Bille
- Copenhagen Hearing and Balance Center, Ear, Nose and Throat (ENT) and Audiology Clinic, Rigshospitalet, Copenhagen University Hospital, Denmark, Inge Lehmanns Vej 8, DK-2100 København Ø, Denmark
| | - Jesper Yde
- Copenhagen Hearing and Balance Center, Ear, Nose and Throat (ENT) and Audiology Clinic, Rigshospitalet, Copenhagen University Hospital, Denmark, Inge Lehmanns Vej 8, DK-2100 København Ø, Denmark
| | - Gerard Encina-Llamas
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark; Copenhagen Hearing and Balance Center, Ear, Nose and Throat (ENT) and Audiology Clinic, Rigshospitalet, Copenhagen University Hospital, Denmark, Inge Lehmanns Vej 8, DK-2100 København Ø, Denmark; Faculty of Medicine. University of Vic - Central University of Catalonia (UVic-UCC), Vic, 08500, Catalonia - Spain
| | - Jens Hjortkjær
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Kettegård Allé 30, DK-2650 Hvidovre, Denmark
| | - Torsten Dau
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark
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Liu J, Stohl J, Overath T. Hidden hearing loss: Fifteen years at a glance. Hear Res 2024; 443:108967. [PMID: 38335624 DOI: 10.1016/j.heares.2024.108967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 01/15/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024]
Abstract
Hearing loss affects approximately 18% of the population worldwide. Hearing difficulties in noisy environments without accompanying audiometric threshold shifts likely affect an even larger percentage of the global population. One of the potential causes of hidden hearing loss is cochlear synaptopathy, the loss of synapses between inner hair cells (IHC) and auditory nerve fibers (ANF). These synapses are the most vulnerable structures in the cochlea to noise exposure or aging. The loss of synapses causes auditory deafferentation, i.e., the loss of auditory afferent information, whose downstream effect is the loss of information that is sent to higher-order auditory processing stages. Understanding the physiological and perceptual effects of this early auditory deafferentation might inform interventions to prevent later, more severe hearing loss. In the past decade, a large body of work has been devoted to better understand hidden hearing loss, including the causes of hidden hearing loss, their corresponding impact on the auditory pathway, and the use of auditory physiological measures for clinical diagnosis of auditory deafferentation. This review synthesizes the findings from studies in humans and animals to answer some of the key questions in the field, and it points to gaps in knowledge that warrant more investigation. Specifically, recent studies suggest that some electrophysiological measures have the potential to function as indicators of hidden hearing loss in humans, but more research is needed for these measures to be included as part of a clinical test battery.
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Affiliation(s)
- Jiayue Liu
- Department of Psychology and Neuroscience, Duke University, Durham, USA.
| | - Joshua Stohl
- North American Research Laboratory, MED-EL Corporation, Durham, USA
| | - Tobias Overath
- Department of Psychology and Neuroscience, Duke University, Durham, USA
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Kamerer AM. A Time-Saving Alternative to "Peak-Picking" Algorithms: A Gaussian Mixture Model Feature Extraction Technique for the Neurodiagnostic Auditory Brainstem Response. Ear Hear 2024:00003446-990000000-00259. [PMID: 38419164 DOI: 10.1097/aud.0000000000001498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
OBJECTIVES The accurate and efficient analysis of neurodiagnostic auditory brainstem responses (ABR) plays a critical role in assessing auditory pathway function in human and animal research and in clinical diagnosis. Traditional analysis of the neurodiagnostic ABR analysis involves visual inspection of the waveform and manually marking peaks and troughs. Visual inspection is a tedious and time-consuming task, especially in research where there may be hundreds or thousands of waveforms to analyze. "Peak-picking" algorithms have made this task faster; however, they are prone to the same errors as visual inspection. A Gaussian mixture model-based feature extraction technique (GMM-FET) is a descriptive model of ABR morphology and an alternative to peak-picking algorithms. The GMM-FET is capable of modeling multiple waves and accounting for wave interactions, compared with other template-matching approaches that fit single waves. DESIGN The present study is a secondary analysis applying the GMM-FET to 321 ABRs from adult humans from 2 datasets using different stimuli and recording parameters. Goodness-of-fit of the GMM-FET to waves I and V and surrounding waves, that is, the summating potential and waves IV and VI, was assessed, and latency and amplitude estimations by the GMM-FET were compared with estimations from visual inspection. RESULTS The GMM-FET had a similar success rate to visual inspection in extracting peak latency and amplitude, and there was low RMS error and high intraclass correlation between the model and response waveform. Mean peak latency differences between the GMM-FET and visual inspection were small, suggesting the two methods chose the same peak in the majority of waveforms. The GMM-FET estimated wave I amplitudes within 0.12 µV of visual inspection, but estimated larger wave V amplitudes than visual inspection. CONCLUSIONS The results suggest the GMM-FET is an appropriate method for extracting peak latencies and amplitudes for neurodiagnostic analysis of ABR waves I and V.
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Affiliation(s)
- Aryn M Kamerer
- Department of Communicative Disorders and Deaf Education, Utah State University, Logan, Utah, USA
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Vasilkov V, Caswell-Midwinter B, Zhao Y, de Gruttola V, Jung DH, Liberman MC, Maison SF. Evidence of cochlear neural degeneration in normal-hearing subjects with tinnitus. Sci Rep 2023; 13:19870. [PMID: 38036538 PMCID: PMC10689483 DOI: 10.1038/s41598-023-46741-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 11/04/2023] [Indexed: 12/02/2023] Open
Abstract
Tinnitus, reduced sound-level tolerance, and difficulties hearing in noisy environments are the most common complaints associated with sensorineural hearing loss in adult populations. This study aims to clarify if cochlear neural degeneration estimated in a large pool of participants with normal audiograms is associated with self-report of tinnitus using a test battery probing the different stages of the auditory processing from hair cell responses to the auditory reflexes of the brainstem. Self-report of chronic tinnitus was significantly associated with (1) reduced cochlear nerve responses, (2) weaker middle-ear muscle reflexes, (3) stronger medial olivocochlear efferent reflexes and (4) hyperactivity in the central auditory pathways. These results support the model of tinnitus generation whereby decreased neural activity from a damaged cochlea can elicit hyperactivity from decreased inhibition in the central nervous system.
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Affiliation(s)
- Viacheslav Vasilkov
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA
| | - Benjamin Caswell-Midwinter
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA
| | - Yan Zhao
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
| | - Victor de Gruttola
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02114, USA
| | - David H Jung
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA
| | - M Charles Liberman
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA
| | - Stéphane F Maison
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA.
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA.
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Colla MDF, Lunardelo PP, Dias FAM. Cochlear synaptopathy and hidden hearing loss: a scoping review. Codas 2023; 36:e20230032. [PMID: 37991055 DOI: 10.1590/2317-1782/20232023032pt] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/10/2023] [Indexed: 11/23/2023] Open
Abstract
PURPOSE To identify the pathophysiological definitions adopted by studies investigating "cochlear synaptopathy" (CS) and "hidden hearing loss" (HHL). RESEARCH STRATEGIES The combination of keywords "Auditory Synaptopathy" or "Neuronal Synaptopathy" or "Hidden Hearing Loss" with "etiology" or "causality" or "diagnosis" was used in the databases EMBASE, Pubmed (MEDLINE), CINAHL (EBSCO), and Web of Science. SELECTION CRITERIA Studies that investigated CS or HHL in humans using behavioral and/or electrophysiological procedures were included. DATA ANALYSIS Data analysis and extraction were performed with regard to terminology, definitions, and population. RESULTS 49 articles were included. Of these, 61.2% used the CS terminology, 34.7% used both terms, and 4.1% used HHL. The most-studied conditions were exposure to noise and tinnitus. CONCLUSION CS terminology was used in most studies, referring to the pathophysiological process of deafferentiation between the cochlear nerve fibers and inner hair cells.
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Affiliation(s)
- Marina de Figueiredo Colla
- Departamento de Fonoaudiologia, Pontifícia Universidade Católica de Minas Gerais - PUC MG - Belo Horizonte (MG), Brasil
| | - Pamela Papile Lunardelo
- Programa de Pós-graduação em Psicobiologia, Universidade de São Paulo de Ribeirão Preto - USP RP - Ribeirão Preto (SP), Brasil
| | - Fernanda Abalen Martins Dias
- Departamento de Fonoaudiologia, Pontifícia Universidade Católica de Minas Gerais - PUC MG - Belo Horizonte (MG), Brasil
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8
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Kim EH, Shin SH, Byun SW, Lee HY. Exploring the origins of decreased sound tolerance in tinnitus patients. Front Neurol 2023; 14:1273705. [PMID: 38020634 PMCID: PMC10657806 DOI: 10.3389/fneur.2023.1273705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
This study aimed to confirm the characteristics of auditory function alterations in tinnitus patients with concomitant decreased sound tolerance (ST) and provide insights for developing tailored therapeutic approaches. A retrospective analysis was conducted on patient records from a tertiary university hospital's tinnitus clinic between March 2020 and June 2023. Demographic attributes and audiological profiles were reviewed. Patients were categorized into Group 1 if loudness discomfort level test outcomes were 77 dB or below, measured using an average of frequencies from 250 Hz to 8 kHz. The remaining patients were allocated to Group 2. Among the 434 tinnitus patients, 115 (26.5%) demonstrated decreased ST and were classified as Group 1. This group exhibited higher DPOAE amplitudes (p < 0.001), shortened latency, and decreased threshold of ABR wave V bilaterally (p < 0.05). No significant disparities were observed in gender, age, tinnitus handicap inventory, visual analog scale, and pure-tone audiometry results except subjective hyperacusis. Binary logistic regression analysis utilizing the forward conditional method revealed that the difference between groups was independently linked to DPOAE response at 7,277 Hz on the left side [B = 0.093, p < 0.001, EXP(B) = 1.07, 95% CI = 1.044-1.153]. Increased DPOAE amplitude and shorter and decreased ABR wave V in tinnitus patients with decreased ST might suggest a possible association with lesions in or around the superior olivary complex or higher central auditory pathway, potentially linked to the inhibition of medial olivocochlear efferents.
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Affiliation(s)
| | | | | | - Ho Yun Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Ewha Womans University School of Medicine, Seoul, Republic of Korea
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9
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Ginsberg H, Singh R, Bharadwaj HM, Heinz MG. A multi-channel EEG mini-cap can improve reliability for recording auditory brainstem responses in chinchillas. J Neurosci Methods 2023; 398:109954. [PMID: 37625650 PMCID: PMC10560491 DOI: 10.1016/j.jneumeth.2023.109954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/17/2023] [Accepted: 08/19/2023] [Indexed: 08/27/2023]
Abstract
BACKGROUND Disabling hearing loss affects nearly 466 million people worldwide (World Health Organization). The auditory brainstem response (ABR) is the most common non-invasive clinical measure of evoked potentials, e.g., as an objective measure for universal newborn hearing screening. In research, the ABR is widely used for estimating hearing thresholds and cochlear synaptopathy in animal models of hearing loss. The ABR contains multiple waves representing neural activity across different peripheral auditory pathway stages, which arise within the first 10 ms after stimulus onset. Multi-channel (e.g., 32 or higher) caps provide robust measures for a wide variety of EEG applications for the study of human hearing. However, translational studies using preclinical animal models typically rely on only a few subdermal electrodes. NEW METHOD We evaluated the feasibility of a 32-channel rodent EEG mini-cap for improving the reliability of ABR measures in chinchillas, a common model of human hearing. RESULTS After confirming initial feasibility, a systematic experimental design tested five potential sources of variability inherent to the mini-cap methodology. We found each source of variance minimally affected mini-cap ABR waveform morphology, thresholds, and wave-1 amplitudes. COMPARISON WITH EXISTING METHOD The mini-cap methodology was statistically more robust and less variable than the conventional subdermal-needle methodology, most notably when analyzing ABR thresholds. Additionally, fewer repetitions were required to produce a robust ABR response when using the mini-cap. CONCLUSIONS These results suggest the EEG mini-cap can improve translational studies of peripheral auditory evoked responses. Future work will evaluate the potential of the mini-cap to improve the reliability of more centrally evoked (e.g., cortical) EEG responses.
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Affiliation(s)
- Hannah Ginsberg
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, 47907, IN, USA.
| | - Ravinderjit Singh
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, 47907, IN, USA; Indiana University School of Medicine, Indianapolis, 46202, IN, USA
| | - Hari M Bharadwaj
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, 47907, IN, USA; Department of Communication Science and Disorders, University of Pittsburgh, Pittsburgh, 15260, PA, USA; Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, 47907, IN, USA
| | - Michael G Heinz
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, 47907, IN, USA; Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, 47907, IN, USA
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10
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Mohamed T, Melfi V, Colciago A, Magnaghi V. Hearing loss and vestibular schwannoma: new insights into Schwann cells implication. Cell Death Dis 2023; 14:629. [PMID: 37741837 PMCID: PMC10517973 DOI: 10.1038/s41419-023-06141-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 09/25/2023]
Abstract
Hearing loss (HL) is the most common and heterogeneous disorder of the sensory system, with a large morbidity in the worldwide population. Among cells of the acoustic nerve (VIII cranial nerve), in the cochlea are present the hair cells, the spiral ganglion neurons, the glia-like supporting cells, and the Schwann cells (SCs), which alterations have been considered cause of HL. Notably, a benign SC-derived tumor of the acoustic nerve, named vestibular schwannoma (VS), has been indicated as cause of HL. Importantly, SCs are the main glial cells ensheathing axons and forming myelin in the peripheral nerves. Following an injury, the SCs reprogram, expressing some stemness features. Despite the mechanisms and factors controlling their biological processes (i.e., proliferation, migration, differentiation, and myelination) have been largely unveiled, their role in VS and HL was poorly investigated. In this review, we enlighten some of the mechanisms at the base of SCs transformation, VS development, and progression, likely leading to HL, and we pose great attention on the environmental factors that, in principle, could contribute to HL onset or progression. Combining the biomolecular bench-side approach to the clinical bedside practice may be helpful for the diagnosis, prediction, and therapeutic approach in otology.
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Affiliation(s)
- Tasnim Mohamed
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", Università degli Studi di Milano, Via G. Balzaretti 9, 20133, Milan, Italy
| | - Valentina Melfi
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", Università degli Studi di Milano, Via G. Balzaretti 9, 20133, Milan, Italy
- Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, 20133, Milan, Italy
| | - Alessandra Colciago
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", Università degli Studi di Milano, Via G. Balzaretti 9, 20133, Milan, Italy
| | - Valerio Magnaghi
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", Università degli Studi di Milano, Via G. Balzaretti 9, 20133, Milan, Italy.
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11
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Haggerty RA, Hutson KA, Riggs WJ, Brown KD, Pillsbury HC, Adunka OF, Buchman CA, Fitzpatrick DC. Assessment of cochlear synaptopathy by electrocochleography to low frequencies in a preclinical model and human subjects. Front Neurol 2023; 14:1104574. [PMID: 37483448 PMCID: PMC10361575 DOI: 10.3389/fneur.2023.1104574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 06/19/2023] [Indexed: 07/25/2023] Open
Abstract
Cochlear synaptopathy is the loss of synapses between the inner hair cells and the auditory nerve despite survival of sensory hair cells. The findings of extensive cochlear synaptopathy in animals after moderate noise exposures challenged the long-held view that hair cells are the cochlear elements most sensitive to insults that lead to hearing loss. However, cochlear synaptopathy has been difficult to identify in humans. We applied novel algorithms to determine hair cell and neural contributions to electrocochleographic (ECochG) recordings from the round window of animal and human subjects. Gerbils with normal hearing provided training and test sets for a deep learning algorithm to detect the presence of neural responses to low frequency sounds, and an analytic model was used to quantify the proportion of neural and hair cell contributions to the ECochG response. The capacity to detect cochlear synaptopathy was validated in normal hearing and noise-exposed animals by using neurotoxins to reduce or eliminate the neural contributions. When the analytical methods were applied to human surgical subjects with access to the round window, the neural contribution resembled the partial cochlear synaptopathy present after neurotoxin application in animals. This result demonstrates the presence of viable hair cells not connected to auditory nerve fibers in human subjects with substantial hearing loss and indicates that efforts to regenerate nerve fibers may find a ready cochlear substrate for innervation and resumption of function.
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Affiliation(s)
- Raymond A. Haggerty
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kendall A. Hutson
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - William J. Riggs
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
| | - Kevin D. Brown
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- University of North Carolina School of Medicine, Chapel Hill, NC, United States
| | - Harold C. Pillsbury
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- University of North Carolina School of Medicine, Chapel Hill, NC, United States
| | - Oliver F. Adunka
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
| | - Craig A. Buchman
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, United States
| | - Douglas C. Fitzpatrick
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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12
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Auditory Electrophysiological and Perceptual Measures in Student Musicians with High Sound Exposure. Diagnostics (Basel) 2023; 13:diagnostics13050934. [PMID: 36900080 PMCID: PMC10000734 DOI: 10.3390/diagnostics13050934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/05/2022] [Accepted: 02/26/2023] [Indexed: 03/06/2023] Open
Abstract
This study aimed to determine (a) the influence of noise exposure background (NEB) on the peripheral and central auditory system functioning and (b) the influence of NEB on speech recognition in noise abilities in student musicians. Twenty non-musician students with self-reported low NEB and 18 student musicians with self-reported high NEB completed a battery of tests that consisted of physiological measures, including auditory brainstem responses (ABRs) at three different stimulus rates (11.3 Hz, 51.3 Hz, and 81.3 Hz), and P300, and behavioral measures including conventional and extended high-frequency audiometry, consonant-vowel nucleus-consonant (CNC) word test and AzBio sentence test for assessing speech perception in noise abilities at -9, -6, -3, 0, and +3 dB signal to noise ratios (SNRs). The NEB was negatively associated with performance on the CNC test at all five SNRs. A negative association was found between NEB and performance on the AzBio test at 0 dB SNR. No effect of NEB was found on the amplitude and latency of P300 and the ABR wave I amplitude. More investigations of larger datasets with different NEB and longitudinal measurements are needed to investigate the influence of NEB on word recognition in noise and to understand the specific cognitive processes contributing to the impact of NEB on word recognition in noise.
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13
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Park Y, Shin SH, Byun SW, Lee ZY, Lee HY. Audiological and psychological assessment of tinnitus patients with normal hearing. Front Neurol 2023; 13:1102294. [PMID: 36712420 PMCID: PMC9878854 DOI: 10.3389/fneur.2022.1102294] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 12/29/2022] [Indexed: 01/15/2023] Open
Abstract
Introduction This study was performed to assess identifiable abnormalities in tinnitus patients with normal hearing. Methods The medical records of subjective non-pulsatile tinnitus patients with normal hearing confirmed by conventional pure-tone audiometry who visited our tinnitus clinic between March 2020 and May 2022 were reviewed. The loudness discomfort level (LDL), extended high-frequency hearing loss (EHFHL), summating potential (SP)/action potential (AP) ratio, distortion product otoacoustic emission (DPOAE), thresholds of auditory brainstem response (ABR) wave V, somatic modulation, and psychiatric symptoms, such as anxiety, depression, and stress were evaluated by questionnaires. Results Decreased LDL (n = 48, 59.8%) was the most frequent finding, followed by EHFHL (n = 29, 35.4%), increased SP/AP ratio (n = 27, 32.9%), psychiatric symptoms (n = 24, 29.3%), decreased DPOAE (n = 17, 20.7%), somatic modulation (n = 8, 9.8%), and increased ABR threshold (n = 3, 3.7%); 75.6% of patients had one or more of these findings. The presence of psychiatric symptoms was independently associated with the Tinnitus Handicap Inventory (THI) score. Conclusion Tinnitus in patients with normal hearing may be accompanied by a combination of various subclinical abnormal audiological findings. However, the presence of psychiatric symptoms alone was independently associated with tinnitus distress.
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14
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Le Prell CG, Clavier OH, Bao J. Noise-induced hearing disorders: Clinical and investigational tools. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:711. [PMID: 36732240 PMCID: PMC9889121 DOI: 10.1121/10.0017002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
A series of articles discussing advanced diagnostics that can be used to assess noise injury and associated noise-induced hearing disorders (NIHD) was developed under the umbrella of the United States Department of Defense Hearing Center of Excellence Pharmaceutical Interventions for Hearing Loss working group. The overarching goals of the current series were to provide insight into (1) well-established and more recently developed metrics that are sensitive for detection of cochlear pathology or diagnosis of NIHD, and (2) the tools that are available for characterizing individual noise hazard as personal exposure will vary based on distance to the sound source and placement of hearing protection devices. In addition to discussing the utility of advanced diagnostics in patient care settings, the current articles discuss the selection of outcomes and end points that can be considered for use in clinical trials investigating hearing loss prevention and hearing rehabilitation.
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Affiliation(s)
- Colleen G Le Prell
- Department of Speech, Language, and Hearing Science, University of Texas at Dallas, Richardson, Texas 75080, USA
| | | | - Jianxin Bao
- Gateway Biotechnology Inc., St. Louis, Missouri 63132, USA
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15
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Van Der Biest H, Keshishzadeh S, Keppler H, Dhooge I, Verhulst S. Envelope following responses for hearing diagnosis: Robustness and methodological considerations. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:191. [PMID: 36732231 DOI: 10.1121/10.0016807] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
Recent studies have found that envelope following responses (EFRs) are a marker of age-related and noise- or ototoxic-induced cochlear synaptopathy (CS) in research animals. Whereas the cochlear injury can be well controlled in animal research studies, humans may have an unknown mixture of sensorineural hearing loss [SNHL; e.g., inner- or outer-hair-cell (OHC) damage or CS] that cannot be teased apart in a standard hearing evaluation. Hence, a direct translation of EFR markers of CS to a differential CS diagnosis in humans might be compromised by the influence of SNHL subtypes and differences in recording modalities between research animals and humans. To quantify the robustness of EFR markers for use in human studies, this study investigates the impact of methodological considerations related to electrode montage, stimulus characteristics, and presentation, as well as analysis method on human-recorded EFR markers. The main focus is on rectangularly modulated pure-tone stimuli to evoke the EFR based on a recent auditory modelling study that showed that the EFR was least affected by OHC damage and most sensitive to CS in this stimulus configuration. The outcomes of this study can help guide future clinical implementations of electroencephalography-based SNHL diagnostic tests.
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Affiliation(s)
- Heleen Van Der Biest
- Hearing Technology at Wireless, Acoustics, Environment and Expert Systems, Department of Information Technology, Ghent, Belgium
| | - Sarineh Keshishzadeh
- Hearing Technology at Wireless, Acoustics, Environment and Expert Systems, Department of Information Technology, Ghent, Belgium
| | - Hannah Keppler
- Department of Rehabilitation Sciences-Audiology, Ghent University, Ghent, Belgium
| | - Ingeborg Dhooge
- Department of Head and Skin, Ghent University, Ghent, Belgium
| | - Sarah Verhulst
- Hearing Technology at Wireless, Acoustics, Environment and Expert Systems, Department of Information Technology, Ghent, Belgium
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16
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Gómez-Álvarez M, Johannesen PT, Coelho-de-Sousa SL, Klump GM, Lopez-Poveda EA. The Relative Contribution of Cochlear Synaptopathy and Reduced Inhibition to Age-Related Hearing Impairment for People With Normal Audiograms. Trends Hear 2023; 27:23312165231213191. [PMID: 37956654 PMCID: PMC10644751 DOI: 10.1177/23312165231213191] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
Older people often show auditory temporal processing deficits and speech-in-noise intelligibility difficulties even when their audiogram is clinically normal. The causes of such problems remain unclear. Some studies have suggested that for people with normal audiograms, age-related hearing impairments may be due to a cognitive decline, while others have suggested that they may be caused by cochlear synaptopathy. Here, we explore an alternative hypothesis, namely that age-related hearing deficits are associated with decreased inhibition. For human adults (N = 30) selected to cover a reasonably wide age range (25-59 years), with normal audiograms and normal cognitive function, we measured speech reception thresholds in noise (SRTNs) for disyllabic words, gap detection thresholds (GDTs), and frequency modulation detection thresholds (FMDTs). We also measured the rate of growth (slope) of auditory brainstem response wave-I amplitude with increasing level as an indirect indicator of cochlear synaptopathy, and the interference inhibition score in the Stroop color and word test (SCWT) as a proxy for inhibition. As expected, performance in the auditory tasks worsened (SRTNs, GDTs, and FMDTs increased), and wave-I slope and SCWT inhibition scores decreased with ageing. Importantly, SRTNs, GDTs, and FMDTs were not related to wave-I slope but worsened with decreasing SCWT inhibition. Furthermore, after partialling out the effect of SCWT inhibition, age was no longer related to SRTNs or GDTs and became less strongly related to FMDTs. Altogether, results suggest that for people with normal audiograms, age-related deficits in auditory temporal processing and speech-in-noise intelligibility are mediated by decreased inhibition rather than cochlear synaptopathy.
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Affiliation(s)
- Marcelo Gómez-Álvarez
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Peter T. Johannesen
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Sónia L. Coelho-de-Sousa
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Georg M. Klump
- Department of Neuroscience and Cluster of Excellence “Hearing4all”, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Enrique A. Lopez-Poveda
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
- Departamento de Cirugía, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain
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17
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Wang J, Wang C, Wang Q, Zhang Z, Wang H, Wang S, Chi Z, Shang L, Wang W, Shu Y. Microfluidic Preparation of Gelatin Methacryloyl Microgels as Local Drug Delivery Vehicles for Hearing Loss Therapy. ACS APPLIED MATERIALS & INTERFACES 2022; 14:46212-46223. [PMID: 36206492 DOI: 10.1021/acsami.2c11647] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Local drug delivery has become an effective method for disease therapy in fine organs including ears, eyes, and noses. However, the multiple anatomical and physiological barriers, unique clearance pathways, and sensitive perceptions characterizing these organs have led to suboptimal drug delivery efficiency. Here, we developed dexamethasone sodium phosphate-encapsulated gelatin methacryloyl (Dexsp@GelMA) microgel particles, with finely tunable size through well-designed microfluidics, as otic drug delivery vehicles for hearing loss therapy. The release kinetics, encapsulation efficiency, drug loading efficiency, and cytotoxicity of the GelMA microgels with different degrees of methacryloyl substitution were comprehensively studied to optimize the microgel formulation. Compared to bulk hydrogels, Dexsp@GelMA microgels of certain sizes hardly cause air-conducted hearing loss in vivo. Besides, strong adhesion of the microgels on the round window membrane was demonstrated. Moreover, the Dexsp@GelMA microgels, via intratympanic administration, could ameliorate acoustic noise-induced hearing loss and attenuate hair cell loss and synaptic ribbons damage more effectively than Dexsp alone. Our results strongly support the adhesive and intricate microfluidic-derived GelMA microgels as ideal intratympanic delivery vehicles for inner ear disease therapies, which provides new inspiration for microfluidics in drug delivery to the fine organs.
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Affiliation(s)
- Jiali Wang
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai200031, P. R. China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai200031, P. R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai200032, P. R. China
- Institutes of Biomedical Sciences, Fudan University, Shanghai200032, P. R. China
| | - Chong Wang
- Institutes of Biomedical Sciences, Fudan University, Shanghai200032, P. R. China
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Fudan University, Shanghai200032, P. R. China
| | - Qiao Wang
- Institutes of Biomedical Sciences, Fudan University, Shanghai200032, P. R. China
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Fudan University, Shanghai200032, P. R. China
| | - Zhuohao Zhang
- Institutes of Biomedical Sciences, Fudan University, Shanghai200032, P. R. China
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Fudan University, Shanghai200032, P. R. China
| | - Hui Wang
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai200031, P. R. China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai200031, P. R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai200032, P. R. China
- Institutes of Biomedical Sciences, Fudan University, Shanghai200032, P. R. China
| | - Shengyi Wang
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai200031, P. R. China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai200031, P. R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai200032, P. R. China
- Institutes of Biomedical Sciences, Fudan University, Shanghai200032, P. R. China
| | - Zhangcai Chi
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai200031, P. R. China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai200031, P. R. China
| | - Luoran Shang
- Institutes of Biomedical Sciences, Fudan University, Shanghai200032, P. R. China
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Fudan University, Shanghai200032, P. R. China
| | - Wuqing Wang
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai200031, P. R. China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai200031, P. R. China
| | - Yilai Shu
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University, Shanghai200031, P. R. China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai200031, P. R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai200032, P. R. China
- Institutes of Biomedical Sciences, Fudan University, Shanghai200032, P. R. China
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18
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Pinsonnault-Skvarenina A, Soucy W, Noël J, Doucet F, Lévesque É, Fuente A, Leroux T. Supra-threshold deficits in normal hearing military recruits exposed to impulse noise. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:2419. [PMID: 36319241 DOI: 10.1121/10.0014829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
The aim of this study was to determine the effect of impulse noise exposure on various proxy measures of cochlear synaptopathy in young military recruits. A total of 27 military recruits with exposure to firearm and artillery noise and 13 non exposed participants were recruited. All presented with normal hearing thresholds and the presence of distortion product otoacoustic emissions (DPOAEs). The Noise Exposure Structured Interview (NESI) was used to quantify noise exposure. Speech perception in noise (SPiN), equivalent rectangular bandwidth (ERB) of auditory filters, auditory brainstem response wave I amplitude, wave I amplitude growth function, wave I/V amplitude ratio, wave V latency, wave V latency shift with ipsilateral noise, and the summating potential/action potential ratio of the electrocochleography were measured. In military participants, SPiN was worse, ERB at 4 kHz was larger, wave I amplitude at 75 dBnHL was reduced, and wave V latency was delayed. However, no significant correlations were observed between NESI and auditory measures, once multiplicity of tests was controlled for. These results suggest that military recruits may exhibit supra-threshold deficits, despite presenting with normal hearing thresholds and presence of DPOAEs. Future studies should include a measure of auditory filters in their test battery.
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Affiliation(s)
| | - William Soucy
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Jonathan Noël
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Félicia Doucet
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Élise Lévesque
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Adrian Fuente
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Tony Leroux
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
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Abstract
PURPOSE OF REVIEW The purpose of this review is to offer a concise summary of current knowledge regarding hidden hearing loss (HHL) and to describe the variety of mechanisms that contribute to its development. We will also discuss the various diagnostic tools that are available as well as future directions. RECENT FINDINGS Hidden hearing loss often also called cochlear synaptopathy affects afferent synapses of the inner hair cells. This description is in contrast to traditional models of hearing loss, which predominantly affects auditory hair cells. In HHL, the synapses of nerve fibres with a slow spontaneous firing rate, which are crucial for locating sound in background noise, are severely impaired. In addition, recent research suggests that HHL may also be related to cochlear nerve demyelination. Noise exposure causes loss of myelin sheath thickness. Auditory brainstem response, envelope-following response and middle-ear muscle reflex are promising diagnostic tests, but they have yet to be validated in humans. SUMMARY Establishing diagnostic tools for cochlear synaptopathy in humans is important to better understand this patient population, predict the long-term outcomes and allow patients to take the necessary protective precautions.
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20
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Valderrama JT, de la Torre A, McAlpine D. The hunt for hidden hearing loss in humans: From preclinical studies to effective interventions. Front Neurosci 2022; 16:1000304. [PMID: 36188462 PMCID: PMC9519997 DOI: 10.3389/fnins.2022.1000304] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 08/29/2022] [Indexed: 11/30/2022] Open
Abstract
Many individuals experience hearing problems that are hidden under a normal audiogram. This not only impacts on individual sufferers, but also on clinicians who can offer little in the way of support. Animal studies using invasive methodologies have developed solid evidence for a range of pathologies underlying this hidden hearing loss (HHL), including cochlear synaptopathy, auditory nerve demyelination, elevated central gain, and neural mal-adaptation. Despite progress in pre-clinical models, evidence supporting the existence of HHL in humans remains inconclusive, and clinicians lack any non-invasive biomarkers sensitive to HHL, as well as a standardized protocol to manage hearing problems in the absence of elevated hearing thresholds. Here, we review animal models of HHL as well as the ongoing research for tools with which to diagnose and manage hearing difficulties associated with HHL. We also discuss new research opportunities facilitated by recent methodological tools that may overcome a series of barriers that have hampered meaningful progress in diagnosing and treating of HHL.
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Affiliation(s)
- Joaquin T. Valderrama
- National Acoustic Laboratories, Sydney, NSW, Australia
- Department of Linguistics, Macquarie University Hearing, Macquarie University, Sydney, NSW, Australia
- *Correspondence: Joaquin T. Valderrama, ;
| | - Angel de la Torre
- Department of Signal Theory, Telematics and Communications, University of Granada, Granada, Spain
- Research Centre for Information and Communications Technologies (CITIC-UGR), University of Granada, Granada, Spain
| | - David McAlpine
- Department of Linguistics, Macquarie University Hearing, Macquarie University, Sydney, NSW, Australia
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21
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Assessment of Hidden Hearing Loss in Individuals Exposed to Occupational Noise Using Cochlear, Neural, Temporal Functions and Quality of Life Measures. Indian J Otolaryngol Head Neck Surg 2022; 74:524-531. [PMID: 36032846 PMCID: PMC9411355 DOI: 10.1007/s12070-021-02373-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 01/05/2021] [Indexed: 10/22/2022] Open
Abstract
The present study aims to identify the objective tests that can identify hidden hearing loss in a group of individuals exposed to occupational noise, which is not otherwise evident as a clinically relevant permanent threshold shift. A standard group comparison design was used to study the hidden auditory effect of occupational noise on traffic police officers. A total of 50 participants (n = 25 exposed to occupational noise; n = 25 non-occupational noise-exposed) were included in the study. The test battery comprised of behavioral tests (hearing thresholds from 250 to 16,000 Hz), fine structure Distortion product otoacoustic emissions (DPOAE's) as physiological measure, Click and CE-chirp® evoked auditory brain stem response (ABR) as electrophysiological, and Gap detection test (GDT) and Temporal modulation transfer function (TMTF) as psychophysical measures. Among the measures evaluated, extended high-frequency audiometry, fine structure DPOAE amplitude, CE-chirp® ABR, GDT, and TMTF showed a significant difference (p < 0.05) between the traffic police individuals exposed to occupational noise and the controls. However, routine audiometry and click-evoked ABR did not show any significant differences. The high-frequency audiometric thresholds, fine structure DPOAEs, CE-chirp® evoked ABR, GDT and TMTF have been shown to be affected in individuals exposed to occupational noise. This finding indicates a hidden hearing loss in the study group. Hence, this study paves the way for early identification and intervention of noise-induced hearing loss by including these measures along with routine test protocol in susceptible individuals.
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22
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Kaf WA, Turntine M, Jamos A, Smurzynski J. Examining the Profile of Noise-Induced Cochlear Synaptopathy Using iPhone Health App Data and Cochlear and Brainstem Electrophysiological Responses to Fast Clicks Rates. Semin Hear 2022; 43:197-222. [PMID: 36313044 PMCID: PMC9605806 DOI: 10.1055/s-0042-1756164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Little is known about objective classifying of noise exposure risk levels in personal listening device (PLD) users and electrophysiologic evidence of cochlear synaptopathy at very fast click rates. The aim of the study was to objectively classify noise exposure risk using iPhone Health app and identify signs of cochlear synaptopathy using behavioral and electrophysiologic measures. Thirty normal-hearing females (aged 18-26 years) were grouped based on their iPhone Health app's 6-month listening level and noise exposure data into low-risk and high-risk groups. They were assessed using a questionnaire, extended high-frequency (EHF) audiometry, QuickSIN test, distortion-product otoacoustic emission (DPOAE), and simultaneous recording of electrocochleography (ECochG) and auditory brainstem response (ABR) at three click rates (19.5/s, 97.7/s, 234.4/s). A series of ANOVAs and independent samples t -test were conducted for group comparison. Both groups had within-normal EHF hearing thresholds and DPOAEs. However, the high-risk participants were over twice as likely to suffer from tinnitus, had abnormally large summating potential to action potential amplitude and area ratios at fast rates, and had slightly smaller waves I and V amplitudes. The high-risk group demonstrated a profile of behavioral and objective signs of cochlear synaptopathy based on ECochG and ABR recordings at fast click rates. The findings in this study suggest that the iPhone Health app may be a useful tool for further investigation into cochlear synaptopathy in PLD users.
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Affiliation(s)
- Wafaa A. Kaf
- Department of Communication Sciences and Disorders, Missouri State University, Springfield, Missouri
| | - Madison Turntine
- Department of Communication Sciences and Disorders, Missouri State University, Springfield, Missouri
| | - Abdullah Jamos
- Department of Communication Sciences and Disorders, Missouri State University, Springfield, Missouri
| | - Jacek Smurzynski
- Department of Audiology and Speech-Language Pathology, East Tennessee State University, Johnson City, Tennessee
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23
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Xia L, Ripley S, Jiang Z, Yin X, Yu Z, Aiken SJ, Wang J. Synaptopathy in Guinea Pigs Induced by Noise Mimicking Human Experience and Associated Changes in Auditory Signal Processing. Front Neurosci 2022; 16:935371. [PMID: 35873820 PMCID: PMC9298651 DOI: 10.3389/fnins.2022.935371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Noise induced synaptopathy (NIS) has been researched extensively since a large amount of synaptic loss without permanent threshold shift (PTS) was found in CBA mice after a brief noise exposure. However, efforts to translate these results to humans have met with little success—and might not be possible since noise exposure used in laboratory animals is generally different from what is experienced by human subjects in real life. An additional problem is a lack of morphological data and reliable functional methods to quantify loss of afferent synapses in humans. Based on evidence for disproportionate synaptic loss for auditory nerve fibers (ANFs) with low spontaneous rates (LSR), coding-in-noise deficits (CIND) have been speculated to be the major difficulty associated with NIS without PTS. However, no robust evidence for this is available in humans or animals. This has led to a re-examination of the role of LSR ANFs in signal coding in high-level noise. The fluctuation profile model has been proposed to support a role for high-SR ANFs in the coding of high-level noise in combination with efferent control of cochlear gain. This study aimed to induce NIS by a low-level, intermittent noise exposure mimicking what is experienced in human life and examined the impact of the NIS on temporal processing under masking. It also evaluated the role of temporal fluctuation in evoking efferent feedback and the effects of NIS on this feedback.
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Affiliation(s)
- Li Xia
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
| | - Sara Ripley
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
| | - Zhenhua Jiang
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
| | - Xue Yin
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
| | - Zhiping Yu
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
| | - Steve J Aiken
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
| | - Jian Wang
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China.,School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
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Pinsonnault-Skvarenina A, Moïn-Darbari K, Zhao W, Zhang M, Qiu W, Fuente A. No effect of occupational noise exposure on auditory brainstem response and speech perception in noise. Front Neurosci 2022; 16:915211. [PMID: 35937884 PMCID: PMC9354017 DOI: 10.3389/fnins.2022.915211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/05/2022] [Indexed: 11/13/2022] Open
Abstract
The primary aim of this study was to investigate whether auditory brainstem response (ABR) and speech perception in noise (SPiN) were associated with occupational noise exposure in normal hearing young factory workers. Forty young adults occupationally exposed to noise and 40 non-exposed young adults (control group) from Zhejiang province in China were selected. All participants presented with normal hearing thresholds and distortion product otoacoustic emissions. Participants were evaluated with the Mandarin Bamford-Kowal-Bench (BKB) test and ABR. The latter was obtained for click stimulus at 50, 60, 70, 80, and 90 dBnHL. Peak-to-trough amplitudes and latencies for waves I and V were obtained. The ABR wave I amplitude, the wave I/V amplitude ratio, the slope of the wave I amplitude growth as a function of stimulus intensity (AMP-ISlope), and the wave V latency shift with ipsilateral noise (LAT-VSlope) were used as ABR outcomes. Finally, equivalent continuous average sound pressure level normalized to 8 h (LAeq.8h) and cumulative noise exposure (CNE) were obtained for noise-exposed participants. No significant differences between groups were found for any ABR outcomes. Noise-exposed participants exhibited worse BKB scores than control group participants. A multivariate regression model showed that 23.3% of the variance in BKB scores was explained by group category (exposed vs. non-exposed) and hearing thresholds. However, since none of the ABR outcomes exploring cochlear synaptopathy were associated with noise exposure, we cannot conclude that cochlear synaptopathy was the contributing factor for the differences between groups for BKB scores. Factors that go beyond sensory processing may explain such results, especially given socio-economic differences between the noise-exposed and control groups. We conclude that in this sample of participants, occupational noise exposure was not associated with signs of cochlear synaptopathy as measured by ABR and BKB.
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Affiliation(s)
- Alexis Pinsonnault-Skvarenina
- École d’Orthophonie et d’Audiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
- Centre de Recherche Interdisciplinaire en Réadaptation du Montréal Métropolitain – CIUSSS du Centre-Sud-de-l’Île-de-Montréal, Montréal, QC, Canada
- Centre for Interdisciplinary Research in Music Media and Technology, McGill University, Montréal, QC, Canada
| | - Karina Moïn-Darbari
- École d’Orthophonie et d’Audiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
- Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal – CIUSSS du Centre-Sud-de-l’ÎIe-de-Montréal, Montréal, QC, Canada
| | - Wulan Zhao
- Zhejiang Chinese Medical University, Hangzhou, China
| | - Meibian Zhang
- National Institute of Occupational Health and Poison Control, Beijing, China
| | - Wei Qiu
- Auditory Research Laboratory, State University of New York at Plattsburgh, Plattsburgh, NY, United States
| | - Adrian Fuente
- École d’Orthophonie et d’Audiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
- Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal – CIUSSS du Centre-Sud-de-l’ÎIe-de-Montréal, Montréal, QC, Canada
- *Correspondence: Adrian Fuente,
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Drakopoulos F, Vasilkov V, Osses Vecchi A, Wartenberg T, Verhulst S. Model-based hearing-enhancement strategies for cochlear synaptopathy pathologies. Hear Res 2022; 424:108569. [DOI: 10.1016/j.heares.2022.108569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/07/2022] [Accepted: 07/12/2022] [Indexed: 11/04/2022]
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26
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Zhang Y, Chen J, Zhang Y, Sun B, Liu Y. Using Auditory Characteristics to Select Hearing Aid Compression Speeds for Presbycusic Patients. Front Aging Neurosci 2022; 14:869338. [PMID: 35847672 PMCID: PMC9285002 DOI: 10.3389/fnagi.2022.869338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 05/20/2022] [Indexed: 11/23/2022] Open
Abstract
Objectives This study aimed to select the optimal hearing aid compression speeds (fast-acting and slow-acting) for presbycusic patients by using auditory characteristics including temporal modulation and speech-in-noise performance. Methods In total, 24 patients with unilateral or bilateral moderate sensorineural hearing loss who scored higher than 21 on the Montreal Cognitive Assessment (MoCA) test participated in this study. The electrocochleogram (ECochG) results, including summating potentials (SP) and action potentials (AP), were recorded. Subjects' temporal modulation thresholds and speech recognition at 4 individualized signal-to-noise ratios were measured under three conditions, namely, unaided, aided with fast-acting compression (FAC), and aided with slow-acting compression (SAC). Results The results of this study showed that modulation discrimination thresholds in the unaided (−8.14 dB) and aided SAC (−8.19 dB) conditions were better than the modulation thresholds in the FAC (−4.67 dB) conditions. The speech recognition threshold (SRT75%) for FAC (5.21 dB) did not differ significantly from SAC (3.39 dB) (p = 0.12). A decision tree analysis showed that the inclusion of the AP, unaided modulation thresholds, and unaided SRT75% may correctly identify the optimal compression speeds (FAC vs. SAC) for individual presbycusic patients with up to 90% accuracy. Conclusion Both modes of compression speeds improved a presbycusic patient's speech recognition ability in noise. The SAC hearing aids may better preserve the modulation thresholds than the FAC hearing aids. The measurement of AP, along with the unaided modulation thresholds and unaided SRT75%, may help guide the selection of optimal compression speeds for individual presbycusic patients.
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Affiliation(s)
- Yi Zhang
- Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jing Chen
- School of Electronics Engineering and Computer Science, Peking University, Beijing, China
| | - Yanmei Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Peking University First Hospital, Beijing, China
| | - Baoxuan Sun
- Widex Hearing Aid (Shanghai) Co., Ltd., Shanghai, China
| | - Yuhe Liu
- Department of Otolaryngology Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, China
- *Correspondence: Yuhe Liu
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27
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Qi G, Shi L, Qin H, Jiang Q, Guo W, Yu N, Han D, Yang S. Morphology changes in the cochlea of impulse noise-induced hidden hearing loss. Acta Otolaryngol 2022; 142:455-462. [PMID: 35723705 DOI: 10.1080/00016489.2022.2086706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
BACKGROUND This study was focused on impulse noise induces hidden hearing loss. OBJECTIVES This study was designed to determine the morphology changes of noise-induced hidden hearing loss (NIHHL). METHOD Fifteen guinea pigs were divided into three groups: noise-induced hidden hearing loss (NIHHL) group, noise-induced hearing loss (NIHL) group, and normal control group. For the NIHHL group, guinea pigs were exposed to 15 times of impulse noise with peak intensity of 163 dB SPL at one time. For the NIHL group, animals were exposed to two rounds of 100 times impulse noise, and the time interval is 24 h. Auditory brain response (ABR) was tested before, immediately, 24 h, one week, and one month after noise exposure to evaluate cochlear physiology changes. One month after noise exposure, all guinea pigs in three groups were sacrificed, and basement membranes were carefully dissected immediately after ABR tests. The cochlea samples were observed by transmission electron microscopy (TEM) to find out the morphology changes. RESULT The ABR results showed that 15 times of impulse noise exposure could cause NIHHL in guinea pigs and 200 times could cause completely hearing loss. Impulse noise exposure could cause a dramatic increase of mitochondria in the inner hair cell. The structures of ribbon synapse and heminode were also obviously impaired compared to the normal group. The nerve fiber and myelin sheath remained intact after impulse noise exposure. CONCLUSION This research revealed that impulse noise could cause hidden hearing loss, and the changes in inner hair cells, ribbon synapse, and heminode all played a vital role in the pathogenesis of hidden hearing loss.
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Affiliation(s)
- Guowei Qi
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, National Clinical Research Center for Otolaryngologic Diseases, State Key Lab of Hearing Science, Ministry of Education, Beijing Key Lab of Hearing Impairment Prevention and Treatment Beijing, Beijing, China.,Graduate School of Navy, Medical University Shanghai, Shanghai, China.,Graduate School of Chinese, PLA General Hospital Beijing, Beijing, China
| | - Lei Shi
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, National Clinical Research Center for Otolaryngologic Diseases, State Key Lab of Hearing Science, Ministry of Education, Beijing Key Lab of Hearing Impairment Prevention and Treatment Beijing, Beijing, China.,Graduate School of Chinese, PLA General Hospital Beijing, Beijing, China
| | - Handai Qin
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, National Clinical Research Center for Otolaryngologic Diseases, State Key Lab of Hearing Science, Ministry of Education, Beijing Key Lab of Hearing Impairment Prevention and Treatment Beijing, Beijing, China.,Graduate School of Chinese, PLA General Hospital Beijing, Beijing, China
| | - Qingqing Jiang
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, National Clinical Research Center for Otolaryngologic Diseases, State Key Lab of Hearing Science, Ministry of Education, Beijing Key Lab of Hearing Impairment Prevention and Treatment Beijing, Beijing, China
| | - Weiwei Guo
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, National Clinical Research Center for Otolaryngologic Diseases, State Key Lab of Hearing Science, Ministry of Education, Beijing Key Lab of Hearing Impairment Prevention and Treatment Beijing, Beijing, China
| | - Ning Yu
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, National Clinical Research Center for Otolaryngologic Diseases, State Key Lab of Hearing Science, Ministry of Education, Beijing Key Lab of Hearing Impairment Prevention and Treatment Beijing, Beijing, China
| | - Dongyi Han
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, National Clinical Research Center for Otolaryngologic Diseases, State Key Lab of Hearing Science, Ministry of Education, Beijing Key Lab of Hearing Impairment Prevention and Treatment Beijing, Beijing, China
| | - Shiming Yang
- Senior Department of Otolaryngology-Head & Neck Surgery, The Sixth Medical Center of PLA General Hospital, National Clinical Research Center for Otolaryngologic Diseases, State Key Lab of Hearing Science, Ministry of Education, Beijing Key Lab of Hearing Impairment Prevention and Treatment Beijing, Beijing, China
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Ripley S, Xia L, Zhang Z, Aiken SJ, Wang J. Animal-to-Human Translation Difficulties and Problems With Proposed Coding-in-Noise Deficits in Noise-Induced Synaptopathy and Hidden Hearing Loss. Front Neurosci 2022; 16:893542. [PMID: 35720689 PMCID: PMC9199355 DOI: 10.3389/fnins.2022.893542] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/22/2022] [Indexed: 12/26/2022] Open
Abstract
Noise induced synaptopathy (NIS) and hidden hearing loss (NIHHL) have been hot topic in hearing research since a massive synaptic loss was identified in CBA mice after a brief noise exposure that did not cause permanent threshold shift (PTS) in 2009. Based upon the amount of synaptic loss and the bias of it to synapses with a group of auditory nerve fibers (ANFs) with low spontaneous rate (LSR), coding-in-noise deficit (CIND) has been speculated as the major difficult of hearing in subjects with NIS and NIHHL. This speculation is based upon the idea that the coding of sound at high level against background noise relies mainly on the LSR ANFs. However, the translation from animal data to humans for NIS remains to be justified due to the difference in noise exposure between laboratory animals and human subjects in real life, the lack of morphological data and reliable functional methods to quantify or estimate the loss of the afferent synapses by noise. Moreover, there is no clear, robust data revealing the CIND even in animals with the synaptic loss but no PTS. In humans, both positive and negative reports are available. The difficulty in verifying CINDs has led a re-examination of the hypothesis that CIND is the major deficit associated with NIS and NIHHL, and the theoretical basis of this idea on the role of LSR ANFs. This review summarized the current status of research in NIS and NIHHL, with focus on the translational difficulty from animal data to human clinicals, the technical difficulties in quantifying NIS in humans, and the problems with the SR theory on signal coding. Temporal fluctuation profile model was discussed as a potential alternative for signal coding at high sound level against background noise, in association with the mechanisms of efferent control on the cochlea gain.
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Affiliation(s)
- Sara Ripley
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
| | - Li Xia
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
| | - Zhen Zhang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Steve J. Aiken
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
| | - Jian Wang
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
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29
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Suthakar K, Liberman MC. Noise Masking in Cochlear Synaptopathy: Auditory Brainstem Response vs. Auditory Nerve Response in Mouse. J Neurophysiol 2022; 127:1574-1585. [PMID: 35583974 PMCID: PMC9169830 DOI: 10.1152/jn.00402.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 04/28/2022] [Accepted: 05/12/2022] [Indexed: 11/22/2022] Open
Abstract
After acoustic overexposure, many auditory-nerve fiber (ANF) synapses permanently retract from surviving cochlear hair cells. This synaptopathy is hard to diagnose, since it does not elevate audiometric thresholds until almost no synapses remain, nevertheless it may degrade discrimination of complex stimuli especially in noisy environments. Here, we study an assay based on masking the auditory brainstem responses (ABRs) to a moderate-level probe tone with continuous noise of varied sound levels, and we investigate the underlying ANF responses at the single-fiber level. Synaptopathy was induced by overexposure to octave-band noise, resulting in a permanent synaptic loss of ~50%, without permanent threshold elevation except at the highest frequencies. The normal progressive delay of ABR peaks with increasing masker level is diminished in synaptopathic ears; however, the single-fiber analysis suggests that this normal latency shift does not arise because contributing ANFs shift from low-threshold fibers (with high spontaneous rates) to high-threshold fibers (with low spontaneous rates). Rather, it may arise because of a shift in the cochlear region dominating the response. Surprisingly, the dynamic range of masking, i.e. the difference between the lowest masker level that attenuates the ABR to a fixed-level probe and the lowest masker level that eliminates the ABR, is enhanced in the synaptopathic ears. This ABR behavior mirrors the single-fiber data showing a paradoxical enhancement of onset-response synchrony and resistance to masking in responses of ANFs in the synaptopathic regions. An assay based on the dynamic range of masking could be useful in diagnosing synaptic damage in human populations.
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Affiliation(s)
- Kirupa Suthakar
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
| | - M Charles Liberman
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
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30
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Harris KC, Bao J. Optimizing non-invasive functional markers for cochlear deafferentation based on electrocochleography and auditory brainstem responses. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:2802. [PMID: 35461487 PMCID: PMC9034896 DOI: 10.1121/10.0010317] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/22/2022] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
Accumulating evidence suggests that cochlear deafferentation may contribute to suprathreshold deficits observed with or without elevated hearing thresholds, and can lead to accelerated age-related hearing loss. Currently there are no clinical diagnostic tools to detect human cochlear deafferentation in vivo. Preclinical studies using a combination of electrophysiological and post-mortem histological methods clearly demonstrate cochlear deafferentation including myelination loss, mitochondrial damages in spiral ganglion neurons (SGNs), and synaptic loss between inner hair cells and SGNs. Since clinical diagnosis of human cochlear deafferentation cannot include post-mortem histological quantification, various attempts based on functional measurements have been made to detect cochlear deafferentation. So far, those efforts have led to inconclusive results. Two major obstacles to the development of in vivo clinical diagnostics include a lack of standardized methods to validate new approaches and characterize the normative range of repeated measurements. In this overview, we examine strategies from previous studies to detect cochlear deafferentation from electrocochleography and auditory brainstem responses. We then summarize possible approaches to improve these non-invasive functional methods for detecting cochlear deafferentation with a focus on cochlear synaptopathy. We identify conceptual approaches that should be tested to associate unique electrophysiological features with cochlear deafferentation.
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Affiliation(s)
- Kelly C Harris
- Department of Otolaryngology, Head & Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, South Carolina 29425, USA
| | - Jianxin Bao
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio 44272, USA
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Are Electrocochleographic Changes an Early Sign of Cochlear Synaptopathy? A Prospective Study in Tinnitus Patients with Normal Hearing. Diagnostics (Basel) 2022; 12:diagnostics12040802. [PMID: 35453851 PMCID: PMC9027360 DOI: 10.3390/diagnostics12040802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 03/22/2022] [Accepted: 03/22/2022] [Indexed: 11/29/2022] Open
Abstract
The mechanism of tinnitus accompanied by a normal audiogram remains elusive. This study aimed to investigate evidence of primary neural degeneration, also known as cochlear synaptopathy, in tinnitus patients with normal hearing thresholds. We analyzed the differences in electrocochleography (ECochG) measurements between normal-hearing subjects with and without tinnitus. Forty-five subjects were enrolled in this study: 21 were in the tinnitus group, defined by chronic tinnitus of over two months’ duration with normal audiometric thresholds, and 24 were in the control group, defined by a lack of tinnitus complaints. Electrocochleograms were evoked by 1, 4, 6, and 8 kHz alternating-polarity tone bursts at sound pressure levels (SPLs) of 90−110 dB. The tinnitus group had smaller action potential (AP) amplitudes than the control group for 1, 4, 6, and 8 kHz tone bursts and showed significant amplitude reduction at 1 kHz 110 dB SPL (p < 0.01), 1 kHz 90 dB SPL (p < 0.05), and 4 kHz 110 dB SPL (p < 0.05). There were no significant differences in the summating potential/action potential (SP/AP) amplitude ratios across the four tested frequencies. A trend of reduced AP amplitudes was found in the tinnitus group, supporting the hypothesis that tinnitus might be associated with primary neural degeneration.
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Auditory brainstem response in unilateral tinnitus patients: does symmetrical hearing thresholds and within-subject comparison affect responses? Eur Arch Otorhinolaryngol 2022; 279:4687-4693. [DOI: 10.1007/s00405-021-07232-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/20/2021] [Indexed: 11/30/2022]
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Edvall NK, Mehraei G, Claeson M, Lazar A, Bulla J, Leineweber C, Uhlén I, Canlon B, Cederroth CR. Alterations in auditory brainstem response distinguish occasional and constant tinnitus. J Clin Invest 2022; 132:155094. [PMID: 35077399 PMCID: PMC8884914 DOI: 10.1172/jci155094] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/19/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The heterogeneity of tinnitus is thought to underlie the lack of objective diagnostic measures. METHODS Longitudinal data from 20,349 participants of the Swedish Longitudinal Occupational Survey of Health (SLOSH) cohort from 2008 to 2018 were used to understand the dynamics of transition between occasional and constant tinnitus. The second part of the study included electrophysiological data from 405 participants of the Swedish Tinnitus Outreach Project (STOP) cohort. RESULTS We determined that with increasing frequency of the occasional perception of self-reported tinnitus, the odds of reporting constant tinnitus after 2 years increases from 5.62 (95% CI, 4.83–6.55) for previous tinnitus (sometimes) to 29.74 (4.82–6.55) for previous tinnitus (often). When previous tinnitus was reported to be constant, the odds of reporting it as constant after 2 years rose to 603.02 (524.74–692.98), suggesting that once transitioned to constant tinnitus, the likelihood of tinnitus to persist was much greater. Auditory brain stem responses (ABRs) from subjects reporting nontinnitus (controls), occasional tinnitus, and constant tinnitus show that wave V latency increased in constant tinnitus when compared with occasional tinnitus or nontinnitus. The ABR from occasional tinnitus was indistinguishable from that of the nontinnitus controls. CONCLUSIONS Our results support the hypothesis that the transition from occasional to constant tinnitus is accompanied by neuronal changes in the midbrain leading to a persisting tinnitus, which is then less likely to remit. FUNDING This study was supported by the GENDER-Net Co-Plus Fund (GNP-182), the European Union’s Horizon 2020 grants no. 848261 (Unification of Treatments and Interventions for Tinnitus [UNITI]) and no. 722046 (European School for Interdisciplinary Tinnitus Research [ESIT]).
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Affiliation(s)
- Niklas K. Edvall
- Laboratory of Experimental Audiology, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | | | - Martin Claeson
- Stress Research Institute (Stressforksningsinsitutet), Stockholm University, Stockholm, Sweden
| | - Andra Lazar
- Hörsel-och Balanskliniken, Karolinska Universitetssjukhuset, Stockholm, Sweden
| | - Jan Bulla
- University of Bergen, Bergen, Norway
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
| | - Constanze Leineweber
- Stress Research Institute (Stressforksningsinsitutet), Stockholm University, Stockholm, Sweden
| | - Inger Uhlén
- Hörsel-och Balanskliniken, Karolinska Universitetssjukhuset, Stockholm, Sweden
| | - Barbara Canlon
- Laboratory of Experimental Audiology, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Christopher R. Cederroth
- Laboratory of Experimental Audiology, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom (UK)
- Hearing Sciences, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
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Auditory Brainstem Response Wave I Amplitude Has Limited Clinical Utility in Diagnosing Tinnitus in Humans. Brain Sci 2022; 12:brainsci12020142. [PMID: 35203907 PMCID: PMC8870703 DOI: 10.3390/brainsci12020142] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/13/2022] [Accepted: 01/18/2022] [Indexed: 11/25/2022] Open
Abstract
Animal studies have discovered that noise, even at levels that produce no permanent threshold shift, may cause cochlear damage and selective nerve degeneration. A hallmark of such damage, or synaptopathy, is recovered threshold but reduced suprathreshold amplitude for the auditory brainstem response (ABR) wave I. The objective of the present study is to evaluate whether the ABR wave I amplitude or slope can be used to diagnose tinnitus in humans. A total of 43 human subjects, consisting of 21 with tinnitus and 22 without tinnitus, participated in the study. The subjects were on average 44 ± 24 (standard deviation) years old and 16 were female; a subgroup of 19 were young adults with normal audiograms from 125 to 8000 Hz. The ABR was measured using ear canal recording tiptrodes for clicks, 1000, 4000 and 8000 Hz tone bursts at 30, 50, and 70 dB nHL. Compared with control subjects, tinnitus subjects did not show reduced ABR wave I amplitude or slope in either the entire group of 21 tinnitus subjects or a subset of tinnitus subjects with normal audiograms. Despite the small sample size and diverse tinnitus population, the present result suggests that low signal-to-noise ratios in non-invasive measurement of the ABR limit its clinical utility in diagnosing tinnitus in humans.
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Evidence for Loss of Activity in Low-Spontaneous-Rate Auditory Nerve Fibers of Older Adults. J Assoc Res Otolaryngol 2022; 23:273-284. [PMID: 35020090 PMCID: PMC8964899 DOI: 10.1007/s10162-021-00827-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 11/29/2021] [Indexed: 10/19/2022] Open
Abstract
Auditory function declines with age, as evidenced by communication difficulties in challenging listening environments for older adults. Declining auditory function may arise, in part, from an age-related loss and/or inactivity of low-spontaneous-rate (SR) auditory nerve (AN) fibers, a subgroup of neurons important for suprathreshold processing. Compared to high-SR fibers, low-SR fibers take longer to recover from prior stimulation. Taking advantage of this difference, the forward-masked recovery function paradigm estimates the relative proportions of low- and high-SR fibers in the AN by quantifying the time needed for AN responses to recover from prior stimulation (ΔTrecovery). Due to the slower recovery of low-SR fibers, ANs that need more time to fully recover (longer ΔTrecovery) are estimated to have a larger proportion of low-SR fibers than ANs that need less time (shorter ΔTrecovery). To test the hypothesis that low-SR fiber activity is reduced in older humans, the current study assessed recovery functions in 32 older and 16 younger adults using the compound action potential. Results show that ΔTrecovery is shorter for older adults than for younger adults, consistent with a theorized age-related loss and/or inactivity of low-SR fibers. ΔTrecovery did not differ between individuals with and without a prior history of noise exposure as assessed by self-report. This study is the first to successfully assess forward-masked recovery functions in both younger and older adults and provides important insights into the structural and functional changes occurring in the AN with increasing age.
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Kiefer L, Koch L, Merdan-Desik M, Gaese BH, Nowotny M. Comparing the electrophysiological effects of traumatic noise exposure between rodents. J Neurophysiol 2022; 127:452-462. [PMID: 35020518 DOI: 10.1152/jn.00081.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Noise-induced hearing deficits are important health problems in the industrialized world. As the underlying physiological dysfunctions are not well understood, research in suitable animal models is urgently needed. Three rodent species (Mongolian gerbil, rat and mouse) were studied to compare the temporal dynamics of noise-induced hearing loss after identical procedures of noise exposure. Auditory brainstem responses (ABRs) were measured before, during and up to eight weeks after noise exposure for threshold determination and ABR waveform analysis. Trauma induction with stepwise increasing sound pressure level was interrupted by five interspersed ABR measurements. Comparing short- and long-term dynamics underlying the following noise-induced hearing loss revealed diverging time courses between the three species. Hearing loss occurred early on during noise exposure in all three rodent species at or above trauma frequency. Initial noise level (105 dB SPL) was most effective in rats while the delayed level-increase to 115 dB SPL affected mice much stronger. Induced temporary threshold shifts in rats and mice were larger in animals with lower pre-trauma ABR thresholds. The increase in activity (gain) along the auditory pathway was derived by comparing the amplitudes of short- and long-latency ABR waveform components. Directly after trauma, significant effects were found for rats (decreasing gain) and mice (increasing gain) while gerbils revealed high individual variability in gain changes. Taken together, our comparative study revealed pronounced species-specific differences in the development of noise-induced hearing loss and the related processing along the auditory pathway.
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Affiliation(s)
- Lenneke Kiefer
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany
| | - Lisa Koch
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany
| | - Melisa Merdan-Desik
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany.,Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, Jena, Germany
| | - Bernhard H Gaese
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany
| | - Manuela Nowotny
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany.,Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, Jena, Germany
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Mahdi P, Pourbakht A, Karimi Yazdi A, Rabbani Anari M, Pirhajati Mahabadi V, Kamali M. Metabotropic glutamate receptor: A new possible therapeutic target for cochlear synaptopathy. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2022; 25:75-83. [PMID: 35656439 PMCID: PMC9118270 DOI: 10.22038/ijbms.2021.59970.13296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 11/24/2021] [Indexed: 11/08/2022]
Abstract
Objectives Cochlear synaptopathy is a common cause of auditory disorders in which glutamate over-activation occurs. Modulating glutamatergic pathways has been proposed to down-regulate post-synaptic excitation. Materials and Methods 12-guinea pigs as sham and test groups were exposed to a 4-kHz noise at 104 dB SPL, for 2 hr. Pre-exposure intra-tympanic injection with LY354740 and normal saline 9% was applied in the test and sham groups. The amplitude growth of ABR-wave-I and wave-III latency shift with noise were considered in pre- and post-exposure times. The synapses were observed by transmission electron-microscopy. Results ABR thresholds recovered 1-week post-exposure in both groups. The reduction of wave-I amplitude at 4, 6, and 8 kHz were statistically different between pre- and 1- day post-exposure and recovered mostly in the sham group. The amount of latency shift in masked ABR was different between pre- and all post-exposure, and the response could not be detected at higher than 50 dB SL noise. However, the response detectability increased to 60 dB SL noise, and the significance of differences between pre- and post-exposure persisted only at the high level of noise in the test group. In electron-microscopy of sham samples, the size of the ribbon was larger, spherical with an irregularity, and hollow. The post-synaptic density was thicker and missed its flat orientation. Conclusion The higher slope of the ABR-wave I amplitude, the more tolerance of noise in masked ABR, concomitant with the histological finding that revealed less synaptic damage, confirmed the therapeutic effect of LY354740 in cochlear synaptopathy.
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Affiliation(s)
- Parvane Mahdi
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences. Tehran, Iran
| | - Akram Pourbakht
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences. Tehran, Iran,Rehabilitation Research Center, Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences. Tehran, Iran,Corresponding author: Akram Pourbakht. Rehabilitation Research Center, Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. Tel: +98-21-22250541;
| | - Alireza Karimi Yazdi
- Department of Otorhinolaryngology-Head and Neck Surgery, Imam Khomeini Educational Hospital Complex, Tehran University of Medical Sciences. Tehran, Iran
| | - Mahtab Rabbani Anari
- Otorhinolaryngology Research Center, Amir-Alam Educational Complex, Tehran University of Medical Sciences. Tehran, Iran
| | - Vahid Pirhajati Mahabadi
- Department of Neurosciences, School of Medicine. Iran University of Medical Sciences. Tehran, Iran
| | - Mohammad Kamali
- Department of Rehabilitation Management, School of Rehabilitation Sciences, Iran University of Medical Sciences. Tehran, Iran
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Delayed Auditory Brainstem Responses (ABR) in children after sight-recovery. Neuropsychologia 2021; 163:108089. [PMID: 34801518 DOI: 10.1016/j.neuropsychologia.2021.108089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 10/29/2021] [Accepted: 11/15/2021] [Indexed: 01/25/2023]
Abstract
Studies in non-human animal models have revealed that in early development, the onset of visual input gates the critical period closure of some auditory functions. The study of rare individuals whose sight was restored after a period of congenital blindness offers the rare opportunity to assess whether early visual input is a prerequisite for the full development of auditory functions in humans as well. Here, we investigated whether a few months of delayed visual onset would affect the development of Auditory Brainstem Responses (ABRs). ABRs are widely used in the clinical practice to assess both functionality and development of the subcortical auditory pathway and, provide reliable data at the individual level. We collected Auditory Brainstem Responses from two case studies, young children (both having less than 5 years of age) who experienced a transient visual deprivation since birth due to congenital bilateral dense cataracts (BC), and who acquired sight at about two months of age. As controls, we tested 41 children (sighted controls, SC) with typical development, as well as two children who were treated (at about two months of age) for congenital monocular cataracts (MC). The SC group data served to predict, at the individual level, wave latencies of each BC and MC participant. Statistics were performed both at the single subject as well as at the group levels on latencies of main ABR waves (I, III, V and SN10). Results revealed delayed response latencies for both BC children compared with the SC group starting from the wave III. Conversely, no difference emerged between MC children and the SC group. These findings suggest that in case the onset of patterned visual input is delayed, the functional development of the subcortical auditory pathway lags behind typical developmental trajectories. Ultimately results are in favor of the presence of a crossmodal sensitive period in the human subcortical auditory system.
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Current topics in hearing research: Deafferentation and threshold independent hearing loss. Hear Res 2021; 419:108408. [PMID: 34955321 DOI: 10.1016/j.heares.2021.108408] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 11/20/2022]
Abstract
Hearing research findings in recent years have begun to change how we think about hearing loss and how we consider the risk of auditory damage from noise exposure. These findings include evidence of noise-induced cochlear damage in the absence of corresponding permanent threshold elevation or evidence of hair cell loss. Animal studies in several species have shown that noise exposures that produce robust but only temporary threshold shifts can permanently damage inner hair cell synaptic ribbons. This type of synaptic degeneration has also been shown to occur as a result of aging in animals and humans. The emergence of these data has motivated a number of clinical studies aimed at identifying the perceptual correlates associated with synaptopathy. The deficits believed to arise from synaptopathy include poorer hearing in background noise, tinnitus and hyperacusis (loudness intolerance). However, the findings from human studies have been mixed. Key questions remain as to whether synaptopathy reliably produces suprathreshold perceptual deficits or whether it serves as an early indicator of auditory damage with suprathreshold deficits emerging later as a function of further cochlear damage. Here, we provide an overview of both human and animal studies that explore the relationship among inner hair cell damage, including loss of afferent synapses, auditory thresholds, and suprathreshold measures of hearing.
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Bramhall NF. Use of the auditory brainstem response for assessment of cochlear synaptopathy in humans. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 150:4440. [PMID: 34972291 PMCID: PMC10880747 DOI: 10.1121/10.0007484] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/07/2021] [Indexed: 06/14/2023]
Abstract
Although clinical use of the auditory brainstem response (ABR) to detect retrocochlear disorders has been largely replaced by imaging in recent years, the discovery of cochlear synaptopathy has thrown this foundational measure of auditory function back into the spotlight. Whereas modern imaging now allows for the noninvasive detection of vestibular schwannomas, imaging technology is not currently capable of detecting cochlear synaptopathy, the loss of the synaptic connections between the inner hair cells and afferent auditory nerve fibers. However, animal models indicate that the amplitude of the first wave of the ABR, a far-field evoked potential generated by the synchronous firing of auditory nerve fibers, is highly correlated with synaptic integrity. This has led to many studies investigating the use of the ABR as a metric of synaptopathy in humans. However, these studies have yielded mixed results, leading to a lack of consensus about the utility of the ABR as an indicator of synaptopathy. This review summarizes the animal and human studies that have investigated the ABR as a measure of cochlear synaptic function, discusses factors that may have contributed to the mixed findings and the lessons learned, and provides recommendations for future use of this metric in the research and clinical settings.
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Affiliation(s)
- Naomi F Bramhall
- Veterans Affairs (VA) Rehabilitation Research & Development Service (RR&D) National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System Portland, Oregon 97239, USA
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AudioChip: A Deep Phenotyping Approach for Deconstructing and Quantifying Audiological Phenotypes of Self-Reported Speech Perception Difficulties. Ear Hear 2021; 43:1023-1036. [PMID: 34860719 PMCID: PMC9010350 DOI: 10.1097/aud.0000000000001158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES About 15% of U.S. adults report speech perception difficulties despite showing normal audiograms. Recent research suggests that genetic factors might influence the phenotypic spectrum of speech perception difficulties. The primary objective of the present study was to describe a conceptual framework of a deep phenotyping method, referred to as AudioChipping, for deconstructing and quantifying complex audiometric phenotypes. DESIGN In a sample of 70 females 18 to 35 years of age with normal audiograms (from 250 to 8000 Hz), the study measured behavioral hearing thresholds (250 to 16,000 Hz), distortion product otoacoustic emissions (1000 to 16,000 Hz), click-evoked auditory brainstem responses (ABR), complex ABR (cABR), QuickSIN, dichotic digit test score, loudness discomfort level, and noise exposure background. The speech perception difficulties were evaluated using the Speech, Spatial, and Quality of Hearing Scale-12-item version (SSQ). A multiple linear regression model was used to determine the relationship between SSQ scores and audiometric measures. Participants were categorized into three groups (i.e., high, mid, and low) using the SSQ scores before performing the clustering analysis. Audiometric measures were normalized and standardized before performing unsupervised k-means clustering to generate AudioChip. RESULTS The results showed that SSQ and noise exposure background exhibited a significant negative correlation. ABR wave I amplitude, cABR offset latency, cABR response morphology, and loudness discomfort level were significant predictors for SSQ scores. These predictors explained about 18% of the variance in the SSQ score. The k-means clustering was used to split the participants into three major groups; one of these clusters revealed 53% of participants with low SSQ. CONCLUSIONS Our study highlighted the relationship between SSQ and auditory coding precision in the auditory brainstem in normal-hearing young females. AudioChip was useful in delineating and quantifying internal homogeneity and heterogeneity in audiometric measures among individuals with a range of SSQ scores. AudioChip could help identify the genotype-phenotype relationship, document longitudinal changes in auditory phenotypes, and pair individuals in case-control groups for the genetic association analysis.
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Wang H, Li B, Lu Y, Han K, Sheng H, Zhou J, Qi Y, Wang X, Huang Z, Song L, Hua Y. Real-time threshold determination of auditory brainstem responses by cross-correlation analysis. iScience 2021; 24:103285. [PMID: 34765914 PMCID: PMC8571499 DOI: 10.1016/j.isci.2021.103285] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/25/2021] [Accepted: 10/13/2021] [Indexed: 12/02/2022] Open
Abstract
Auditory brainstem response (ABR) serves as an objective indication of auditory perception at a given sound level and is nowadays widely used in hearing function assessment. Despite efforts for automation over decades, ABR threshold determination by machine algorithms remains unreliable and thereby one still relies on visual identification by trained personnel. Here, we described a procedure for automatic threshold determination that can be used in both animal and human ABR tests. The method terminates level averaging of ABR recordings upon detection of time-locked waveform through cross-correlation analysis. The threshold level was then indicated by a dramatic increase in the sweep numbers required to produce “qualified” level averaging. A good match was obtained between the algorithm outcome and the human readouts. Moreover, the method varies the level averaging based on the cross-correlation, thereby adapting to the signal-to-noise ratio of sweep recordings. These features empower a robust and fully automated ABR test. Automatic threshold determination of auditory brainstem response (ABR) Detection of “clear” responses from iteratively averaged level representation Wide application in both animal and human ABR tests Stop on-going level averaging based on detection outcome
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Affiliation(s)
- Haoyu Wang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.,Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bei Li
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China
| | - Yan Lu
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Kun Han
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China
| | - Haibin Sheng
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Jialei Zhou
- Department of Otorhinolaryngology-Head & Neck Surgery, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yumeng Qi
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xueling Wang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Zhiwu Huang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Lei Song
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Yunfeng Hua
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.,Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Qiu S, Zhao W, Gao X, Li D, Wang W, Gao B, Han W, Yang S, Dai P, Cao P, Yuan Y. Syndromic Deafness Gene ATP6V1B2 Controls Degeneration of Spiral Ganglion Neurons Through Modulating Proton Flux. Front Cell Dev Biol 2021; 9:742714. [PMID: 34746137 PMCID: PMC8568048 DOI: 10.3389/fcell.2021.742714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
ATP6V1B2 encodes the V1B2 subunit in V-ATPase, a proton pump responsible for the acidification of lysosomes. Mutations in this gene cause DDOD syndrome, DOORS syndrome, and Zimmermann-Laband syndrome, which share overlapping feature of congenital sensorineural deafness, onychodystrophy, and different extents of intellectual disability without or with epilepsy. However, the underlying mechanisms remain unclear. To investigate the pathological role of mutant ATP6V1B2 in the auditory system, we evaluated auditory brainstem response, distortion product otoacoustic emissions, in a transgenic line of mice carrying c.1516 C > T (p.Arg506∗) in Atp6v1b2, Atp6v1b2 Arg506*/Arg506* . To explore the pathogenic mechanism of neurodegeneration in the auditory pathway, immunostaining, western blotting, and RNAscope analyses were performed in Atp6v1b2Arg506*/Arg506* mice. The Atp6v1b2Arg506*/Arg506* mice showed hidden hearing loss (HHL) at early stages and developed late-onset hearing loss. We observed increased transcription of Atp6v1b1 in hair cells of Atp6v1b2Arg506*/Arg506* mice and inferred that Atp6v1b1 compensated for the Atp6v1b2 dysfunction by increasing its own transcription level. Genetic compensation in hair cells explains the milder hearing impairment in Atp6v1b2Arg506*/Arg506* mice. Apoptosis activated by lysosomal dysfunction and the subsequent blockade of autophagic flux induced the degeneration of spiral ganglion neurons and further impaired the hearing. Intraperitoneal administration of the apoptosis inhibitor, BIP-V5, improved both phenotypical and pathological outcomes in two live mutant mice. Based on the pathogenesis underlying hearing loss in Atp6v1b2-related syndromes, systemic drug administration to inhibit apoptosis might be an option for restoring the function of spiral ganglion neurons and promoting hearing, which provides a direction for future treatment.
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Affiliation(s)
- Shiwei Qiu
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China.,The Institute of Audiology and Balance Science, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou Medical University, Xuzhou, China
| | - Weihao Zhao
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China.,Department of Otolaryngology General Hospital of Tibet Military Region, Lhasa, China
| | - Xue Gao
- Department of Otolaryngology, PLA Rocket Force Characteristic Medical Center, Beijing, China
| | - Dapeng Li
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Weiqian Wang
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Bo Gao
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Weiju Han
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Shiming Yang
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Pu Dai
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Peng Cao
- National Institute of Biological Sciences, Beijing, China
| | - Yongyi Yuan
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
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Verdoodt D, Peeleman N, Szewczyk K, Van Camp G, Ponsaerts P, Van Rompaey V. Cochlin Deficiency Protects Aged Mice from Noise-Induced Hearing Loss. Int J Mol Sci 2021; 22:ijms222111549. [PMID: 34768980 PMCID: PMC8584124 DOI: 10.3390/ijms222111549] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/19/2021] [Accepted: 10/23/2021] [Indexed: 12/18/2022] Open
Abstract
Several studies have shown that type IV fibrocytes, located in the spiral ligament, degenerate first after noise exposure. Interestingly, this is the region where Coch expression is most abundant. As it is suggested that cochlin plays a role in our innate immune system, our goal is to investigate hearing thresholds and inner ear inflammation after noise exposure in Coch knockout (Coch−/−) mice compared to Coch wildtype (Coch+/+) mice. Animals were randomly allocated to a noise exposure group and a control group. Vestibular and auditory testing was performed at 48 h and one week after noise exposure. Whole mount staining and cryosectioning of the cochlea was performed in order to investigate hair cells, spiral ganglion neurons, inner ear inflammation, Coch expression and fibrocyte degeneration. Hearing assessment revealed that Coch+/+ mice had significantly larger threshold shifts than Coch−/− mice after noise exposure. We were unable to identify any differences in hair cells, neurons, fibrocytes and influx of macrophages in the inner ear between both groups. Interestingly, Coch expression was significantly lower in the group exposed to noise. Our results indicate that the absence of Coch has a protective influence on hearing thresholds after noise exposure, but this is not related to reduced inner ear inflammation in the knockout.
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Affiliation(s)
- Dorien Verdoodt
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (N.P.); (K.S.); (V.V.R.)
- Laboratory of Experimental Hematology, Faculty of Medicine and Health Sciences, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, 2610 Wilrijk, Belgium;
- Correspondence: ; Tel.: +32-477-89-98-92
| | - Noa Peeleman
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (N.P.); (K.S.); (V.V.R.)
| | - Krystyna Szewczyk
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (N.P.); (K.S.); (V.V.R.)
| | - Guy Van Camp
- Centre of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp, 2650 Edegem, Belgium;
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, Faculty of Medicine and Health Sciences, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, 2610 Wilrijk, Belgium;
| | - Vincent Van Rompaey
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (N.P.); (K.S.); (V.V.R.)
- Department of Otorhinolaryngology and Head & Neck Surgery, Antwerp University Hospital, 2650 Edegem, Belgium
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Large-scale phenotyping of ABR P1-N1 amplitudes before and after exposure to noise in 69 strains of mice. Mamm Genome 2021; 32:427-434. [PMID: 34487237 DOI: 10.1007/s00335-021-09913-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/30/2021] [Indexed: 01/13/2023]
Abstract
ABR wave I amplitude represents the synapse of auditory nerve fibers with the inner hair cell and is highly correlated with synapse counts. Cochlear synaptopathy, the loss of synaptic connections between inner hair cells and auditory nerve fibers, has been well-demonstrated in animal models of noise-induced hearing loss. The peak-to-peak wave I amplitude was determined at baseline and 2 weeks after noise exposure. We determined the ABR wave I amplitude at 80 dB SPL at the frequencies of 8, 12, 16, 24, and 32 kHz. A total of 69 strains (1-8 mice/strain) were analyzed. A statistically significant post-noise reduction in wave I amplitude was observed in all the tested frequencies (p < 0.00001). We identify distinct patterns of noise susceptibility and make this complete phenotypic dataset available for general use. This data establishes a new resource for the study of NIHL in mice and we hope this database will be a useful tool to expand the research in this field.
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Cochlear Synaptopathy: A Primary Factor Affecting Speech Recognition Performance in Presbycusis. BIOMED RESEARCH INTERNATIONAL 2021; 2021:6667531. [PMID: 34409106 PMCID: PMC8367534 DOI: 10.1155/2021/6667531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 05/11/2021] [Accepted: 07/27/2021] [Indexed: 11/23/2022]
Abstract
The results of recent animal studies have suggested that cochlear synaptopathy may be an important factor involved in presbycusis. Therefore, here, we aimed to examine whether cochlear synaptopathy frequently exists in patients with presbycusis and to describe the effect of cochlear synaptopathy on speech recognition in noise. Based on the medical history and an audiological examination, 94 elderly patients with bilateral, symmetrical, sensorineural hearing loss were diagnosed as presbycusis. An electrocochleogram, auditory brainstem responses, auditory cortical evoked potentials, and speech audiometry were recorded to access the function of the auditory pathway. First, 65 ears with hearing levels of 41-50 dB HL were grouped based on the summating potential/action potential (SP/AP) ratio, and the amplitudes of AP and SP were compared between the two resulting groups. Second, 188 ears were divided into two groups: the normal SP/AP and abnormal SP/AP groups. The speech recognition abilities in the two groups were compared. Finally, the relationship between abnormal electrocochleogram and poor speech recognition (signal-to-noise ratio loss ≥7 dB) was analyzed in 188 ears. The results of the present study showed: (1) a remarkable reduction in the action potential amplitude was observed in patients with abnormal SP/AP ratios; this suggests that cochlear synaptopathy was involved in presbycusis. (2) There was a large proportion of patients with poor speech recognition in the abnormal SP/AP group. Furthermore, a larger number of cases with abnormal SP/AP ratios were confirmed among patients with presbycusis and poor speech recognition. We concluded that cochlear synaptopathy is not uncommon among elderly individuals who have hearing ability deficits, and it may have a more pronounced effect on ears with declining auditory performance in noisy environments.
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Lyu AR, Kim TH, Shin SA, Kim EH, Yu Y, Gajbhiye A, Kwon HC, Je AR, Huh YH, Park MJ, Park YH. Hearing Impairment in a Mouse Model of Diabetes Is Associated with Mitochondrial Dysfunction, Synaptopathy, and Activation of the Intrinsic Apoptosis Pathway. Int J Mol Sci 2021; 22:ijms22168807. [PMID: 34445504 PMCID: PMC8395823 DOI: 10.3390/ijms22168807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/26/2021] [Accepted: 08/13/2021] [Indexed: 11/16/2022] Open
Abstract
Although previous studies continuously report an increased risk of hearing loss in diabetes patients, the impact of the disease on the inner ear remains unexplored. Herein, we examine the pathophysiology of diabetes-associated hearing impairment and cochlear synaptopathy in a mouse model of diabetes. Male B6.BKS(D)-Leprdb/J (db/db, diabetes) and heterozygote (db/+, control) mice were assigned into each experimental group (control vs. diabetes) based on the genotype and tested for hearing sensitivity every week from 6 weeks of age. Each cochlea was collected for histological and biological assays at 14 weeks of age. The diabetic mice exerted impaired hearing and a reduction in cochlear blood flow and C-terminal-binding protein 2 (CtBP2, a presynaptic ribbon marker) expression. Ultrastructural images revealed severely damaged mitochondria from diabetic cochlea accompanied by a reduction in Cytochrome c oxidase subunit 4 (COX4) and CR6-interacting factor 1 (CRIF1). The diabetic mice presented significantly decreased levels of platelet endothelial cell adhesion molecule (PECAM-1), B-cell lymphoma 2 (BCL-2), and procaspase-9, but not procaspase-8. Importantly, significant changes were not found in necroptotic programmed cell death markers (receptor-interacting serine/threonine-protein kinase 1, RIPK1; RIPK3; and mixed lineage kinase domain-like pseudokinase, MLKL) between the groups. Taken together, diabetic hearing loss is accompanied by synaptopathy, microangiopathy, damage to the mitochondrial structure/function, and activation of the intrinsic apoptosis pathway. Our results imply that mitochondrial dysfunction is deeply involved in diabetic hearing loss, and further suggests the potential benefits of therapeutic strategies targeting mitochondria.
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Affiliation(s)
- Ah-Ra Lyu
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (A.-R.L.); (E.-H.K.); (Y.Y.)
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (A.G.); (H.-C.K.)
| | - Tae-Hwan Kim
- Biomedical Convergence Research Center, Chungnam National University Hospital, Daejeon 35015, Korea;
| | - Sun-Ae Shin
- Brain Research Institute, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
| | - Eung-Hyub Kim
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (A.-R.L.); (E.-H.K.); (Y.Y.)
| | - Yang Yu
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (A.-R.L.); (E.-H.K.); (Y.Y.)
| | - Akanksha Gajbhiye
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (A.G.); (H.-C.K.)
| | - Hyuk-Chan Kwon
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (A.G.); (H.-C.K.)
| | - A Reum Je
- Electron Microscopy Research Center, Korea Basic Science Institute, Cheongju 28119, Korea; (A.R.J.); (Y.H.H.)
| | - Yang Hoon Huh
- Electron Microscopy Research Center, Korea Basic Science Institute, Cheongju 28119, Korea; (A.R.J.); (Y.H.H.)
| | - Min Jung Park
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (A.-R.L.); (E.-H.K.); (Y.Y.)
- Brain Research Institute, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
- Correspondence: (M.J.P.); (Y.-H.P.)
| | - Yong-Ho Park
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (A.-R.L.); (E.-H.K.); (Y.Y.)
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea; (A.G.); (H.-C.K.)
- Biomedical Convergence Research Center, Chungnam National University Hospital, Daejeon 35015, Korea;
- Brain Research Institute, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
- Correspondence: (M.J.P.); (Y.-H.P.)
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Decreased Reemerging Auditory Brainstem Responses Under Ipsilateral Broadband Masking as a Marker of Noise-Induced Cochlear Synaptopathy. Ear Hear 2021; 42:1062-1071. [PMID: 33625059 DOI: 10.1097/aud.0000000000001009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVES In mammals, a 2-hr exposure to an octave-band noise (OBN) at 100 to 108 dB SPL induces loss of synaptic ribbons between inner hair cells and auditory nerve fibers with high thresholds of response (hiT neurons), that encode high-intensity sounds. Here, we tackle the challenge of diagnosing this synaptopathy by a noninvasive functional audiological test, ultimately in humans, despite the expected absence of auditory-threshold elevation and of clear electrophysiological abnormality, hiT neuron contributions being hidden by those of more sensitive and robust neurons. DESIGN The noise-induced synaptopathy was replicated in mice (at 94, 97, and 100 dB SPL; n = 7, 7, and 8, respectively, against 8 unexposed controls), without long-lasting auditory-threshold elevation despite a twofold decrease in ribbon-synapse number for the 100-dB OBN exposure. Auditory brainstem responses (ABRs) were collected using a simultaneous broadband noise masker just able to erase the ABR response to a 60-dB tone burst. Tone burst intensity was then increased up to 100 dB SPL for eliciting reemerging ABRs (R-ABRs), dependent on hiT neurons as more sensitive neurons are masked. RESULTS In most ears exposed to 97-dB-SPL and all ears exposed to 100-dB-SPL OBN, contrary to controls, R-ABRs from the overexposed region have vanished, whereas standard ABR distributions widely overlap. CONCLUSIONS R-ABRs afford an individual noninvasive marker of normal-auditory-threshold cochlear synaptopathy. A simple modification of standard ABRs would allow hidden auditory synaptopathy to be searched in a patient. ABBREVIATIONS ABR: auditory brainstem response; dB SPL: decibel sound pressure level; DPOAE: distortion-product otoacoustic emission; hiT neuron: high-threshold neuron; IHC: inner hair cell; loT neuron: low-threshold neuron; OBN: octave-band noise; OHC: outer hair cell; PBS: phosphate buffer saline; R-ABR: reemerging ABR.
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Bieber RE, Fernandez K, Zalewski C, Cheng H, Brewer CC. Stability of Early Auditory Evoked Potential Components Over Extended Test-Retest Intervals in Young Adults. Ear Hear 2021; 41:1461-1469. [PMID: 33136623 PMCID: PMC8849594 DOI: 10.1097/aud.0000000000000872] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVES Synaptic damage from noise exposures can occur even in the absence of changes in hearing sensitivity in animal models. There is an unmet clinical need for measurements sensitive to such damage to the human auditory system that can augment the pure-tone audiogram. Early components (i.e., <10 msec) of the auditory evoked potential (AEP) may be useful noninvasive indicators of synaptic integrity. Wave I is a measure of synchronous neural activity at the level of the synapse between cochlear inner hair cells and the auditory nerve and may be of particular clinical utility. This amplitude measure has historically been classified as too variable in humans to be used for clinical waveform interpretation, though several recent reliability studies have challenged this view. The focus of the present study is to examine across-session stability of early AEP amplitude measures. DESIGN In this study, amplitudes of early components (wave I, wave V, summating potential [SP]) of the AEP were measured in a cohort of 38 young adults aged 19 to 33 years (21 female). Stability of these amplitude measures was examined in a subset of 12 young adults (8 female), at time intervals ranging from 15 hr to 328 days between tests. Eligibility criteria included normal pure-tone hearing sensitivity, normal tympanometry, and intact acoustic reflexes. Participants were tested at up to four time points. Each evaluation included pure-tone thresholds, tympanometry, speech-in-noise testing, distortion-product otoacoustic emissions (DPOAE), and early AEPs. AEPs were collected in response to click and tone burst stimuli, with both ear canal and mastoid electrode montages. RESULTS No clinical changes in pure-tone hearing were found between baseline and follow-up visits. Intraclass correlation coefficients (ICCs) indicated good to excellent reliability for wave I and wave V peak-to-trough amplitudes within individuals across time, with greatest reliability (0.92, 95% confidence interval [0.81 to 0.96]) and largest amplitudes for wave I when measured from the ear canal in response to a click stimulus. Other measures such as amplitude ratios of waves V/I and the SP and action potential (AP) showed lower ICC values when measured from the ear canal, with SP/AP ratio demonstrating the lowest reliability. CONCLUSIONS The results of this study suggest that, when recorded under certain conditions, wave I amplitude can be a stable measure in humans. These findings are consistent with previous work and may inform the development of clinical protocols that utilize wave I amplitude to infer inner ear integrity.
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Affiliation(s)
- Rebecca E. Bieber
- University of Maryland College Park, College Park MD
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD
| | - Katharine Fernandez
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD
| | - Chris Zalewski
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD
| | - Hui Cheng
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD
| | - Carmen C. Brewer
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD
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