301
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Bramhall NF, McMillan GP, Gallun FJ, Konrad-Martin D. Auditory brainstem response demonstrates that reduced peripheral auditory input is associated with self-report of tinnitus. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3849. [PMID: 31795660 DOI: 10.1121/1.5132708] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Tinnitus is one of the predicted perceptual consequences of cochlear synaptopathy, a type of age-, noise-, or drug-induced auditory damage that has been demonstrated in animal models to cause homeostatic changes in central auditory gain. Although synaptopathy has been observed in human temporal bones, assessment of this condition in living humans is limited to indirect non-invasive measures such as the auditory brainstem response (ABR). In animal models, synaptopathy is associated with a reduction in ABR wave I amplitude at suprathreshold stimulus levels. Several human studies have explored the relationship between wave I amplitude and tinnitus, with conflicting results. This study investigates the hypothesis that reduced peripheral auditory input due to synaptic/neuronal loss is associated with tinnitus. Wave I amplitude data from 193 individuals [43 with tinnitus (22%), 150 without tinnitus (78%)], who participated in up to 3 out of 4 different studies, were included in a logistic regression analysis to estimate the relationship between wave I amplitude and tinnitus at a variety of stimulus levels and frequencies. Statistical adjustment for sex and distortion product otoacoustic emissions (DPOAEs) was included. The results suggest that smaller wave I amplitudes and/or lower DPOAE levels are associated with an increased probability of tinnitus.
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Affiliation(s)
- Naomi F Bramhall
- Department of Veterans Affairs (VA) Rehabilitation Research and Development Service (RR&D), National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System, Portland, Oregon 97239, USA
| | - Garnett P McMillan
- Department of Veterans Affairs (VA) Rehabilitation Research and Development Service (RR&D), National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System, Portland, Oregon 97239, USA
| | - Frederick J Gallun
- Department of Veterans Affairs (VA) Rehabilitation Research and Development Service (RR&D), National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System, Portland, Oregon 97239, USA
| | - Dawn Konrad-Martin
- Department of Veterans Affairs (VA) Rehabilitation Research and Development Service (RR&D), National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System, Portland, Oregon 97239, USA
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302
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Kamerer AM, Kopun JG, Fultz SE, Allen C, Neely ST, Rasetshwane DM. Examining physiological and perceptual consequences of noise exposure. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3947. [PMID: 31795718 PMCID: PMC6881192 DOI: 10.1121/1.5132291] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 05/07/2019] [Accepted: 05/14/2019] [Indexed: 05/08/2023]
Abstract
The consequences of noise exposure on the auditory system are not entirely understood. In animals, noise exposure causes selective synaptopathy-an uncoupling of auditory nerve fibers from sensory cells-mostly in fibers that respond to high sound levels. Synaptopathy can be measured physiologically in animals, but a direct relationship between noise exposure and synaptopathy in humans has yet to be proven. Sources of variability, such as age, indirect measures of noise exposure, and comorbid auditory disorders, obfuscate attempts to find concrete relationships between noise exposure, synaptopathy, and perceptual consequences. This study adds to the ongoing effort by examining relationships between noise exposure, auditory brainstem response (ABR) amplitudes, and speech perception in adults of various ages and audiometric thresholds and a subset of younger adults with clinically normal hearing. Regression models including noise exposure, age, hearing thresholds, and sex as covariates were compared to find a best-fitting model of toneburst ABR wave I amplitude at two frequencies and word recognition performance in three listening conditions: background noise, time compression, and time compression with reverberation. The data suggest the possibility of detecting synaptopathy in younger adults using physiological measures, but that age and comorbid hearing disorders may hinder attempts to assess noise-induced synaptopathy.
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Affiliation(s)
- Aryn M Kamerer
- Boys Town National Research Hospital, Omaha, Nebraska 68131, USA
| | - Judy G Kopun
- Boys Town National Research Hospital, Omaha, Nebraska 68131, USA
| | - Sara E Fultz
- Boys Town National Research Hospital, Omaha, Nebraska 68131, USA
| | - Carissa Allen
- Boys Town National Research Hospital, Omaha, Nebraska 68131, USA
| | - Stephen T Neely
- Boys Town National Research Hospital, Omaha, Nebraska 68131, USA
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303
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Clifford RE, Hertzano R, Ohlemiller KK. Untangling the genomics of noise-induced hearing loss and tinnitus: Contributions of Mus musculus and Homo sapiens. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:4007. [PMID: 31795683 PMCID: PMC7273513 DOI: 10.1121/1.5132552] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/07/2019] [Accepted: 06/24/2019] [Indexed: 05/23/2023]
Abstract
Acoustic trauma is a feature of the industrial age, in general, and mechanized warfare, in particular. Noise-induced hearing loss (NIHL) and tinnitus have been the number 1 and number 2 disabilities at U.S. Veterans hospitals since 2006. In a reversal of original protocols to identify candidate genes associated with monogenic deafness disorders, unbiased genome-wide association studies now direct animal experiments in order to explore genetic variants common in Homo sapiens. However, even these approaches must utilize animal studies for validation of function and understanding of mechanisms. Animal research currently focuses on genetic expression profiles since the majority of variants occur in non-coding regions, implying regulatory divergences. Moving forward, it will be important in both human and animal research to define the phenotypes of hearing loss and tinnitus, as well as exposure parameters, in order to extricate genes related to acoustic trauma versus those related to aging. It has become clear that common disorders like acoustic trauma are influenced by large numbers of genes, each with small effects, which cumulatively lead to susceptibility to a disorder. A polygenic risk score, which aggregates these small effect sizes of multiple genes, may offer a more accurate description of risk for NIHL and/or tinnitus.
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Affiliation(s)
- Royce E Clifford
- Division of Otolaryngology-Head and Neck Surgery, University of California School of Medicine, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Ronna Hertzano
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, James T. Frenkil Building, 16 South Eutaw Street, Suite 500, Baltimore, Maryland 21201, USA
| | - Kevin K Ohlemiller
- Washington University School of Medicine, Department of Otolaryngology, Central Institute for the Deaf at Washington University School of Medicine, Fay and Carl Simons Center for Hearing and Deafness, 660 South Euclid Avenue, Saint Louis, Missouri 63110, USA
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304
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Szobota S, Mathur PD, Siegel S, Black K, Saragovi HU, Foster AC. BDNF, NT-3 and Trk receptor agonist monoclonal antibodies promote neuron survival, neurite extension, and synapse restoration in rat cochlea ex vivo models relevant for hidden hearing loss. PLoS One 2019; 14:e0224022. [PMID: 31671109 PMCID: PMC6822712 DOI: 10.1371/journal.pone.0224022] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 10/03/2019] [Indexed: 12/21/2022] Open
Abstract
Neurotrophins and their mimetics are potential treatments for hearing disorders because of their trophic effects on spiral ganglion neurons (SGNs) whose connections to hair cells may be compromised in many forms of hearing loss. Studies in noise or ototoxin-exposed animals have shown that local delivery of NT-3 or BDNF has beneficial effects on SGNs and hearing. We evaluated several TrkB or TrkC monoclonal antibody agonists and small molecules, along with BDNF and NT-3, in rat cochlea ex vivo models. The TrkB agonists BDNF and a monoclonal antibody, M3, had the greatest effects on SGN survival, neurite outgrowth and branching. In organotypic cochlear explants, BDNF and M3 enhanced synapse formation between SGNs and inner hair cells and restored these connections after excitotoxin-induced synaptopathy. Loss of these synapses has recently been implicated in hidden hearing loss, a condition characterized by difficulty hearing speech in the presence of background noise. The unique profile of M3 revealed here warrants further investigation, and the broad activity profile of BDNF observed underpins its continued development as a hearing loss therapeutic.
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Affiliation(s)
- Stephanie Szobota
- Otonomy, Inc., San Diego, California, United States of America
- * E-mail:
| | | | - Sairey Siegel
- Otonomy, Inc., San Diego, California, United States of America
| | | | - H. Uri Saragovi
- Lady Davis Institute-Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| | - Alan C. Foster
- Otonomy, Inc., San Diego, California, United States of America
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305
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Lee CY, Chen HC, Wu PH, Chi JCY, Sun CC, Huang JY, Lin HY, Yang SF. Increased incidence of age-related macular degeneration in sensorineural hearing loss: A population-based cohort study. PLoS One 2019; 14:e0222919. [PMID: 31644539 PMCID: PMC6808445 DOI: 10.1371/journal.pone.0222919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 08/29/2019] [Indexed: 12/26/2022] Open
Abstract
Background To evaluate the incidence of age-related macular degeneration (AMD) in patients diagnosed with sensorineural hearing loss (SNHL) via the application of the National Health Insurance Research Database in Taiwan. Methodology/Principal findings A retrospective cohort study was conducted. Patients with a diagnosis of SNHL was enrolled in the study group after exclusion and a propensity score matched group without SNHL was served as the control group with a 1:2 ratio. The main outcome was regarded as the emergence of AMD diagnostic codes. Cox proportional hazard regression was applied to analyze the incidence and adjusted hazard ratio (aHR) of AMD in the multivariate model. A total of 15,686 patients with SNHL were included in the study group while another 31,372 non-SNHL patients served as the control group. After a follow-up interval up to 16 years, there were 484 AMD events occurred in the study group and 660 AMD cases in those non-SNHL patients with a significantly higher aHR compared to the control group after adjusting for multiple potential risk factors (aHR: 1.399, 95% CI: 1.244–1.574). Other prominent risk factors for AMD included older age, ischemic heart disease, hyperlipidemia, Alzheimer's disease, liver disease and kidney disease. Besides, a higher cumulative probability of AMD was observed in the study group (log-rank P <0.0001). Conclusion The patients with SNHL demonstrated a higher incidence of developing AMD.
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Affiliation(s)
- Chia-Yi Lee
- Department of Ophthalmology, Show Chwan Memorial Hospital, Changhua, Taiwan
- Department of Optometry, College of Medicine and Life Science, Chung Hwa University of Medical Technology, Tainan, Taiwan
| | - Hung-Chi Chen
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou, Taiwan
- Department of Medicine, Chang Gung University College of Medicine, Taoyuan, Taiwan
- Center for Tissue Engineering, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Pei-Hsuan Wu
- Department of Otolaryngology–Head and Neck Surgery, Tri-Service General Hospital, Taipei, Taiwan
| | - Jessie Chao-Yun Chi
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Otorhinolaryngology Head and Neck Surgery, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan
| | - Chi-Chin Sun
- Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung, Taiwan
- Department of Chinese Medicine, Chang Gung University, Taoyuan City, Taiwan
| | - Jing-Yang Huang
- Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Hung-Yu Lin
- Department of Ophthalmology, Show Chwan Memorial Hospital, Changhua, Taiwan
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Optometry, Chung Shan Medical University, Taichung, Taiwan
- Department of Exercise and Health Promotion, Chung Chou University of Science and Technology, Changhua, Taiwan
- * E-mail: (S-FY); (H-YL)
| | - Shun-Fa Yang
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan
- * E-mail: (S-FY); (H-YL)
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306
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Welling DB, Jackler RK. Reflections on the Last 25 Years of the American Otological Society and Thoughts on its Future. Otol Neurotol 2019. [PMID: 29533378 DOI: 10.1097/mao.0000000000001760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PURPOSE To review contributions of the American Otological Society (AOS) over the most recent quarter century (1993-2018) and to comment on possible future evolution of the field during the quarter century to come. METHODS Retrospective review of selected topics from the AOS transactions, distinguished lectureships over the past 25 years, and selective reflection by the authors. Speculation on potential advances of the next quarter century derived from emerging topics in the current literature and foreseeable trends in science and technology are also proffered for consideration (and possible future ridicule). RESULTS Integration of multiple disciplines including bioengineering, medical imaging, genetics, molecular biology, physics, and evidence based medicine have substantially benefitted the practice of otology over the past quarter century. The impact of the contributions of members of the AOS in these developments cannot be over estimated. CONCLUSIONS Further scientific advancement will certainly accelerate change in the practice of otologic surgery and medicine over the coming decade in ways that will be marvelous to behold.
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Affiliation(s)
- D Bradley Welling
- Harvard Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Robert K Jackler
- Department of Otolaryngology Head and Neck Surgery, Stanford University, Stanford, California
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307
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Sahley TL, Anderson DJ, Hammonds MD, Chandu K, Musiek FE. Evidence for a dynorphin-mediated inner ear immune/inflammatory response and glutamate-induced neural excitotoxicity: an updated analysis. J Neurophysiol 2019; 122:1421-1460. [DOI: 10.1152/jn.00595.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acoustic overstimulation (AOS) is defined as the stressful overexposure to high-intensity sounds. AOS is a precipitating factor that leads to a glutamate (GLU)-induced Type I auditory neural excitotoxicity and an activation of an immune/inflammatory/oxidative stress response within the inner ear, often resulting in cochlear hearing loss. The dendrites of the Type I auditory neural neurons that innervate the inner hair cells (IHCs), and respond to the IHC release of the excitatory neurotransmitter GLU, are themselves directly innervated by the dynorphin (DYN)-bearing axon terminals of the descending brain stem lateral olivocochlear (LOC) system. DYNs are known to increase GLU availability, potentiate GLU excitotoxicity, and induce superoxide production. DYNs also increase the production of proinflammatory cytokines by modulating immune/inflammatory signal transduction pathways. Evidence is provided supporting the possibility that the GLU-mediated Type I auditory neural dendritic swelling, inflammation, excitotoxicity, and cochlear hearing loss that follow AOS may be part of a brain stem-activated, DYN-mediated cascade of inflammatory events subsequent to a LOC release of DYNs into the cochlea. In support of a DYN-mediated cascade of events are established investigations linking DYNs to the immune/inflammatory/excitotoxic response in other neural systems.
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Affiliation(s)
- Tony L. Sahley
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio
- School of Health Sciences, Cleveland State University, Cleveland, Ohio
| | - David J. Anderson
- Department of Chemistry, Cleveland State University, Cleveland, Ohio
| | | | - Karthik Chandu
- Department of Chemistry, Cleveland State University, Cleveland, Ohio
| | - Frank E. Musiek
- Department of Speech, Language, and Hearing Sciences, University of Arizona, Tucson, Arizona
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308
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Lin X, Li G, Zhang Y, Zhao J, Lu J, Gao Y, Liu H, Li GL, Yang T, Song L, Wu H. Hearing consequences in Gjb2 knock-in mice: implications for human p.V37I mutation. Aging (Albany NY) 2019; 11:7416-7441. [PMID: 31562289 PMCID: PMC6782001 DOI: 10.18632/aging.102246] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 08/22/2019] [Indexed: 01/09/2023]
Abstract
Human p.V37I mutation of GJB2 gene was strongly correlated with late-onset progressive hearing loss, especially among East Asia populations. We generated a knock-in mouse model based on human p.V37I variant (c.109G>A) that recapitulated the human phenotype. Cochlear pathology revealed no significant hair cell loss, stria vascularis atrophy or spiral ganglion neuron loss, but a significant change in the length of gap junction plaques, which may have contributed to the observed mild endocochlear potential (EP) drop in homozygous mice lasting lifetime. The cochlear amplification in homozygous mice was compromised, but outer hair cells' function remained unchanged, indicating that the reduced amplification was EP- rather than prestin-generated. In addition to ABR threshold elevation, ABR wave I latencies were also prolonged in aged homozygous animals. We found in homozygous IHCs a significant increase in ICa but no change in Ca2+ efficiency in triggering exocytosis. Environmental insults such as noise exposure, middle ear injection of KCl solution and systemic application of furosemide all exacerbated the pathological phenotype in homozygous mice. We conclude that this Gjb2 mutation-induced hearing loss results from 1) reduced cochlear amplifier caused by lowered EP, 2) IHCs excitotoxicity associated with potassium accumulation around hair cells, and 3) progression induced by environmental insults.
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Affiliation(s)
- Xin Lin
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Gen Li
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Yu Zhang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Jingjing Zhao
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Jiawen Lu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Yunge Gao
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Huihui Liu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Geng-Lin Li
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Tao Yang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Lei Song
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
| | - Hao Wu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai 200125, China
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309
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Lin S, Lin X, Ye S, Lin Y, Shu B, Hu J, Lin D. Is there "hidden hearing loss" in patients with chronic rhinosinusitis? Int J Audiol 2019; 59:124-131. [PMID: 31522578 DOI: 10.1080/14992027.2019.1658906] [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: 10/26/2022]
Abstract
Objective: This study was to investigate whether there is impairment of auditory function in chronic rhinosinusitis (CRS).Study sample: A total of 85 patients were allocated into either the CRS group (n = 65) or a simple deviated nasal septum group (n = 20). Both groups without other risk factors for sensorineural hearing loss exhibited normal thresholds at standard audiometric frequencies. Another group (n = 30) of healthy subjects without CRS or a deviated nasal septum were gender and age matched.Design: Analyse the results of audiology test including pure tone audiometry, an acoustic impedance test, distortion product otoacoustic emissions (DPOAE) and the auditory brainstem response (ABR) for each subject analyse the test results of for each object.Results: The group differences were statistically significant for each high-frequency pure tone (p < 0.05). The ABR showed a difference between groups in amplitude. The DPOAE pass rate of the CRS group was lower than that of the control group.Conclusions: This study showed a significant correlation between CRS and auditory impairment. CRS might impair cochlear functions by damaging inner ear hair cells and/or, outer hair cells (OHCs), consequently altering the activity of the entire auditory pathway originating in the ventral cochlear nucleus (VCN) to the inferior colliculus.
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Affiliation(s)
- Shaolian Lin
- Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Fuzhou, PR China
| | - Xi Lin
- Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Fuzhou, PR China
| | - Shengnan Ye
- Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Fuzhou, PR China
| | - Youhui Lin
- Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Fuzhou, PR China
| | - Bo Shu
- Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Fuzhou, PR China
| | - Jie Hu
- Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Fuzhou, PR China
| | - Dingding Lin
- Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Fuzhou, PR China
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310
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Abstract
Over 450 million people worldwide suffer from hearing loss, leading to an estimated economic burden of ∼$750 billion. The past decade has seen significant advances in the understanding of the molecular mechanisms that contribute to hearing, and the environmental and genetic factors that can go awry and lead to hearing loss. This in turn has sparked enormous interest in developing gene therapy approaches to treat this disorder. This review documents the most recent advances in cochlear gene therapy to restore hearing loss, and will cover viral vectors and construct designs, potential routes of delivery into the inner ear, and, lastly, the most promising genes of interest.
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Affiliation(s)
- Lawrence Lustig
- Department of Otolaryngology-Head and Neck Surgery, Columbia University Medical Center, New York Presbyterian Hospital, New York, New York 10032
| | - Omar Akil
- Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, San Francisco, California 94117
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311
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Bhatt IS, Wang J. Evaluation of dichotic listening performance in normal-hearing, noise-exposed young females. Hear Res 2019; 380:10-21. [PMID: 31167151 DOI: 10.1016/j.heares.2019.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 05/07/2019] [Accepted: 05/26/2019] [Indexed: 10/26/2022]
Abstract
Recent animal studies have shown that intense noise exposures that produce robust temporary threshold shift (TTS) can inflict irreversible damage to the synaptic connections between the inner hair cells and auditory neurons. It was hypothesized that noise-induced cochlear synaptopathy may cause impaired acoustic encoding in the central auditory nervous system leading to impaired speech perception, particularly in challenging listening situations. The aim of the study was to evaluate the influence of high noise exposure background (NEB) on dichotic listening performance, speech-in-noise performance, and auditory brainstem responses (ABR) measured in young females with normal audiograms. The central hypothesis was that individuals with high NEB would exhibit reduced ABR wave I amplitude and subsequently would exhibit poorer performance on speech-in-noise and dichotic listening. In a sample of 32 females (14 with high NEB and 18 with low NEB) aged 18-35 years, the study compared behavioral hearing thresholds (from 250 to 16000 Hz), distortion-product otoacoustic emissions (DPOAEs, 1000-16000 Hz), click-evoked ABR, QuickSIN signal-to-noise ratio (SNR) loss and dichotic digit test (DDT). The results showed no clear association between NEB, and hearing thresholds, DPOAEs, click-evoked ABR measures, and QuickSIN SNR loss. Individuals with high NEB revealed significantly lower DDT scores and evidence of reduced right ear advantage compared to individuals with low NEB. The poorer performance in DDT and the ear asymmetry in DDT scores with normal ABR findings suggest that high NEB might alter the hemispheric organization of speech-sound processing and cognitive control. The clinical significance of the present findings is discussed.
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Affiliation(s)
- Ishan Sunilkumar Bhatt
- Department of Communication Sciences & Disorders, Northern Arizona University, Flagstaff, AZ, 86011, USA.
| | - Jin Wang
- Department of Mathematics & Statistics, Northern Arizona University, Flagstaff, AZ, 86011, USA
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312
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Zinc-finger protein A20 protects hair cells from damage made by high-power microwave. JOURNAL OF BIO-X RESEARCH 2019. [DOI: 10.1097/jbr.0000000000000039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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313
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Bureš Z, Profant O, Svobodová V, Tóthová D, Vencovský V, Syka J. Speech Comprehension and Its Relation to Other Auditory Parameters in Elderly Patients With Tinnitus. Front Aging Neurosci 2019; 11:219. [PMID: 31496946 PMCID: PMC6713070 DOI: 10.3389/fnagi.2019.00219] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 08/02/2019] [Indexed: 11/13/2022] Open
Abstract
Deteriorated speech comprehension is a common manifestation of the age-related decline of auditory functions (presbycusis). It could be assumed that when presbycusis is accompanied by tinnitus, general hearing functions, and particularly comprehension of speech in quiet and speech in noise (SIN), will be significantly affected. In this study, speech comprehension ability and other parameters of auditory function were assessed in elderly subjects with (T, n = 25) and without (NT, n = 26) tinnitus, aiming for examination of both peripheral and central auditory processing. Apart from high-frequency audiograms in quiet and in background noise, speech recognition thresholds in silence or in competitive babble noise, and the ability to understand temporally gated speech (GS), we measured also sensitivity to frequency modulation (FM) and interaural delay, gap detection thresholds (GDT), or the difference limens of intensity. The results show that in elderly participants matched by age (mean ages around 68 years), cognitive status (median MoCA scores around 27), and hearing thresholds [median pure-tone averages (PTA) around 16 dB hearing loss (HL)], tinnitus per se has little influence on speech comprehension. The tinnitus patients also show similar GDT, sensitivity to interaural intensity difference, and sensitivity to FM as the NT subjects. Despite these similarities, nevertheless, significant differences in auditory processing have been found in the tinnitus participants: a worse ability to detect tones in noise, a higher sensitivity to intensity changes, and a higher sensitivity to interaural time differences. Additional correlation analyses further revealed that speech comprehension in the T subjects is dependent on the sensitivity to temporal modulation and interaural time delay (ITD), while these correlations are weak and non-significant in the NT subjects. Therefore, despite similarities in average speech comprehension and several other parameters of auditory function, elderly people with tinnitus exhibit different auditory processing, particularly at a suprathreshold level. The results also suggest that speech comprehension ability of elderly tinnitus patients relies more on temporal features of the sound stimuli, especially under difficult conditions, compared to elderly people without tinnitus.
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Affiliation(s)
- Zbyněk Bureš
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Technical Studies, College of Polytechnics, Jihlava, Czechia
| | - Oliver Profant
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Otorhinolaryngology of Faculty Hospital Královské Vinohrady and 3rd Faculty of Medicine, Charles University, Prague, Czechia
| | - Veronika Svobodová
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine, Charles University in Prague, University Hospital Motol, Prague, Czechia
| | - Diana Tóthová
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine, Charles University in Prague, University Hospital Motol, Prague, Czechia
| | - Václav Vencovský
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Radioelectronics, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czechia
| | - Josef Syka
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
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314
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Chien HW, Wu PH, Wang K, Sun CC, Huang JY, Yang SF, Chen HC, Lee CY. Increased Incidence of Glaucoma in Sensorineural Hearing Loss: A Population-Based Cohort Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16162907. [PMID: 31416136 PMCID: PMC6720936 DOI: 10.3390/ijerph16162907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/11/2019] [Accepted: 08/12/2019] [Indexed: 01/08/2023]
Abstract
The purpose of the current study was to evaluate the incidence of glaucoma in patients diagnosed with sensorineural hearing loss (SNHL) via the application of the National Health Insurance Research Database in Taiwan. A retrospective cohort study was conducted. Patients with a diagnosis of SNHL were enrolled in the study group after an exclusion procedure and a propensity score matched group without SNHL was served as the control group with a 1:2 ratio. The main outcome was regarded as the emergence of glaucoma diagnostic codes. Cox proportional hazard regression was applied to analyze the incidence and adjusted hazard ratio (aHR) of glaucoma in the multivariate model. A total of 15,686 patients diagnosed with SNHL were enrolled in the study group while another 31,372 non-SNHL individuals served as the control group. There were 444 glaucoma events in the study group and 647 glaucoma events in those non-SNHL individuals after the follow-up interval of 16 years. The study group demonstrated a significantly higher aHR compared to the control group after adjusting for multiple possible risk factors. In the subgroup analysis, both the normal tension glaucoma and angle closure glaucoma subgroups revealed a higher aHR in the study group. In conclusion, the patients with SNHL demonstrated a higher incidence of developing glaucoma. Moreover, the incidence was more prominent for patients diagnosed with normal tension glaucoma and angle closure glaucoma.
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Affiliation(s)
- Hsiang-Wen Chien
- Institute of Medicine, Chung Shan Medical University, Taichung 402, Taiwan
- Departments of Ophthalmology, Sijhih Cathay General Hospital, New Taipei City 221, Taiwan
- Department of Ophthalmology, Cathay General Hospital, Taipei 106, Taiwan
| | - Pei-Hsuan Wu
- Department of Otolaryngology-Head and Neck Surgery, Tri-Service General Hospital, Taipei 114, Taiwan
| | - Kai Wang
- Institute of Medicine, Chung Shan Medical University, Taichung 402, Taiwan
- Departments of Ophthalmology, Sijhih Cathay General Hospital, New Taipei City 221, Taiwan
- Department of Ophthalmology, Cathay General Hospital, Taipei 106, Taiwan
| | - Chi-Chin Sun
- Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung 204, Taiwan
- Department of Chinese Medicine, Chang Gung University, Taoyuan City 333, Taiwan
| | - Jing-Yang Huang
- Department of Medical Research, Chung Shan Medical University Hospital, Taichung 402, Taiwan
| | - Shun-Fa Yang
- Institute of Medicine, Chung Shan Medical University, Taichung 402, Taiwan
- Department of Medical Research, Chung Shan Medical University Hospital, Taichung 402, Taiwan
| | - Hung-Chi Chen
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou 333, Taiwan.
- Department of Medicine, Chang Gung University College of Medicine, Taoyuan 333, Taiwan.
- Center for Tissue Engineering, Chang Gung Memorial Hospital, Linkou 333, Taiwan.
| | - Chia-Yi Lee
- Department of Ophthalmology, Show Chwan Memorial Hospital, Changhua 500, Taiwan.
- Department of Optometry, College of Medicine and Life Science, Chung Hwa University of Medical Technology, Tainan 717, Taiwan.
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315
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Han BR, Lin SC, Espinosa K, Thorne PR, Vlajkovic SM. Inhibition of the Adenosine A 2A Receptor Mitigates Excitotoxic Injury in Organotypic Tissue Cultures of the Rat Cochlea. Cells 2019; 8:cells8080877. [PMID: 31408967 PMCID: PMC6721830 DOI: 10.3390/cells8080877] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/09/2019] [Accepted: 08/09/2019] [Indexed: 12/20/2022] Open
Abstract
The primary loss of cochlear glutamatergic afferent nerve synapses due to noise or ageing (cochlear neuropathy) often presents as difficulties in speech discrimination in noisy conditions (hidden hearing loss (HHL)). Currently, there is no treatment for this condition. Our previous studies in mice with genetic deletion of the adenosine A2A receptor (A2AR) have demonstrated better preservation of cochlear afferent synapses and spiral ganglion neurons after noise exposure compared to wildtype mice. This has informed our current targeted approach to cochlear neuroprotection based on pharmacological inhibition of the A2AR. Here, we have used organotypic tissue culture of the Wistar rat cochlea at postnatal day 6 (P6) to model excitotoxic injury induced by N-methyl-d-aspartate (NMDA)/kainic acid (NK) treatment for 2 h. The excitotoxic injury was characterised by a reduction in the density of neural processes immediately after NK treatment and loss of afferent synapses in the presence of intact sensory hair cells. The administration of istradefylline (a clinically approved A2AR antagonist) reduced deafferentation of inner hair cells and improved the survival of afferent synapses after excitotoxic injury. This study thus provides evidence that A2AR inhibition promotes cochlear recovery from excitotoxic injury, and may have implications for the treatment of cochlear neuropathy and prevention of HHL.
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Affiliation(s)
- Belinda Rx Han
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Shelly Cy Lin
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Kristan Espinosa
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Peter R Thorne
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Srdjan M Vlajkovic
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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316
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Encina-Llamas G, Harte JM, Dau T, Shinn-Cunningham B, Epp B. Investigating the Effect of Cochlear Synaptopathy on Envelope Following Responses Using a Model of the Auditory Nerve. J Assoc Res Otolaryngol 2019; 20:363-382. [PMID: 31102010 PMCID: PMC6646444 DOI: 10.1007/s10162-019-00721-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 04/08/2019] [Indexed: 12/16/2022] Open
Abstract
The healthy auditory system enables communication in challenging situations with high levels of background noise. Yet, despite normal sensitivity to pure tones, many listeners complain about having difficulties in such situations. Recent animal studies demonstrated that noise overexposure that produces temporary threshold shifts can cause the loss of auditory nerve (AN) fiber synapses (i.e., cochlear synaptopathy, CS), which appears to predominantly affect medium- and low-spontaneous rate (SR) fibers. In the present study, envelope following response (EFR) magnitude-level functions were recorded in normal hearing (NH) threshold and mildly hearing-impaired (HI) listeners with thresholds elevated above 2 kHz. EFRs were elicited by sinusoidally amplitude modulated (SAM) tones presented in quiet with a carrier frequency of 2 kHz, modulated at 93 Hz, and modulation depths of 0.85 (deep) and 0.25 (shallow). While EFR magnitude-level functions for deeply modulated tones were similar for all listeners, EFR magnitudes for shallowly modulated tones were reduced at medium stimulation levels in some NH threshold listeners and saturated in all HI listeners for the whole level range. A phenomenological model of the AN was used to investigate the extent to which hair-cell dysfunction and/or CS could explain the trends observed in the EFR data. Hair-cell dysfunction alone, including postulated elevated hearing thresholds at extended high frequencies (EHF) beyond 8 kHz, could not account for the recorded EFR data. Postulated CS led to simulations generally consistent with the recorded data, but a loss of all types of AN fibers was required within the model framework. The effects of off-frequency contributions (i.e., away from the characteristic place of the stimulus) and the differential loss of different AN fiber types on EFR magnitude-level functions were analyzed. When using SAM tones in quiet as the stimulus, model simulations suggested that (1) EFRs are dominated by the activity of high-SR fibers at all stimulus intensities, and (2) EFRs at medium-to-high stimulus levels are dominated by off-frequency contributions.
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Affiliation(s)
- Gerard Encina-Llamas
- Hearing Systems section, Department of Health Technology, Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
| | - James M Harte
- Interacoustics Research Unit, Kongens Lyngby, Denmark
| | - Torsten Dau
- Hearing Systems section, Department of Health Technology, Technical University of Denmark (DTU), Kongens Lyngby, Denmark
| | - Barbara Shinn-Cunningham
- Carnegie Mellon Neuroscience Institute, Pittsburgh, PA, USA
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Bastian Epp
- Hearing Systems section, Department of Health Technology, Technical University of Denmark (DTU), Kongens Lyngby, Denmark
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317
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Subclinical cochlear dysfunction in newly diagnosed relapsing-remitting multiple sclerosis. Mult Scler Relat Disord 2019; 33:55-60. [DOI: 10.1016/j.msard.2019.05.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 04/23/2019] [Accepted: 05/26/2019] [Indexed: 01/10/2023]
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318
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Zhang L, Wu C, Martel DT, West M, Sutton MA, Shore SE. Remodeling of cholinergic input to the hippocampus after noise exposure and tinnitus induction in Guinea pigs. Hippocampus 2019; 29:669-682. [PMID: 30471164 PMCID: PMC7357289 DOI: 10.1002/hipo.23058] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/23/2018] [Accepted: 11/03/2018] [Indexed: 01/12/2023]
Abstract
Here, we investigate remodeling of hippocampal cholinergic inputs after noise exposure and determine the relevance of these changes to tinnitus. To assess the effects of noise exposure on the hippocampus, guinea pigs were exposed to unilateral noise for 2 hr and 2 weeks later, immunohistochemistry was performed on hippocampal sections to examine vesicular acetylcholine transporter (VAChT) expression. To evaluate whether the changes in VAChT were relevant to tinnitus, another group of animals was exposed to the same noise band twice to induce tinnitus, which was assessed using gap-prepulse Inhibition of the acoustic startle (GPIAS) 12 weeks after the first noise exposure, followed by immunohistochemistry. Acoustic Brainstem Response (ABR) thresholds were elevated immediately after noise exposure for all experimental animals but returned to baseline levels several days after noise exposure. ABR wave I amplitude-intensity functions did not show any changes after 2 or 12 weeks of recovery compared to baseline levels. In animals assessed 2-weeks following noise-exposure, hippocampal VAChT puncta density decreased on both sides of the brain by 20-60% in exposed animals. By 12 weeks following the initial noise exposure, changes in VAChT puncta density largely recovered to baseline levels in exposed animals that did not develop tinnitus, but remained diminished in animals that developed tinnitus. These tinnitus-specific changes were particularly prominent in hippocampal synapse-rich layers of the dentate gyrus and areas CA3 and CA1, and VAChT density in these regions negatively correlated with tinnitus severity. The robust changes in VAChT labeling in the hippocampus 2 weeks after noise exposure suggest involvement of this circuitry in auditory processing. After chronic tinnitus induction, tinnitus-specific changes occurred in synapse-rich layers of the hippocampus, suggesting that synaptic processing in the hippocampus may play an important role in the pathophysiology of tinnitus.
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Affiliation(s)
- Liqin Zhang
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, Michigan, USA
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan, USA
- Xiangya Medical School, Central South University, Changsha, Hunan, China
| | - Calvin Wu
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, Michigan, USA
| | - David T. Martel
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael West
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael A. Sutton
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, Michigan, USA
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- Correspondence to: Michael A. Sutton, Molecular and Behavioral Neuroscience Institute, 5067, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA. Tel: 734-615-2445; ; Susan E. Shore, Kresge Hearing Research Institute, 5434, Medical Science Building, 1100 W. Medical Center Drive, Ann Arbor, MI 48109, USA. Tel: 734-647-2116;
| | - Susan E. Shore
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
- Correspondence to: Michael A. Sutton, Molecular and Behavioral Neuroscience Institute, 5067, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA. Tel: 734-615-2445; ; Susan E. Shore, Kresge Hearing Research Institute, 5434, Medical Science Building, 1100 W. Medical Center Drive, Ann Arbor, MI 48109, USA. Tel: 734-647-2116;
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319
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Barry K, Robertson D, Mulders W. Changes in auditory thalamus neural firing patterns after acoustic trauma in rats. Hear Res 2019; 379:89-97. [DOI: 10.1016/j.heares.2019.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 04/24/2019] [Accepted: 05/02/2019] [Indexed: 12/28/2022]
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320
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AAV-Mediated Neurotrophin Gene Therapy Promotes Improved Survival of Cochlear Spiral Ganglion Neurons in Neonatally Deafened Cats: Comparison of AAV2-hBDNF and AAV5-hGDNF. J Assoc Res Otolaryngol 2019; 20:341-361. [PMID: 31222416 PMCID: PMC6646500 DOI: 10.1007/s10162-019-00723-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 04/15/2019] [Indexed: 01/22/2023] Open
Abstract
Outcomes with contemporary cochlear implants (CI) depend partly upon the survival and condition of the cochlear spiral ganglion (SG) neurons. Previous studies indicate that CI stimulation can ameliorate SG neural degeneration after deafness, and brain-derived neurotrophic factor (BDNF) delivered by an osmotic pump can further improve neural survival. However, direct infusion of BDNF elicits undesirable side effects, and osmotic pumps are impractical for clinical application. In this study, we explored the potential for two adeno-associated viral vectors (AAV) to elicit targeted neurotrophic factor expression in the cochlea and promote improved SG and radial nerve fiber survival. Juvenile cats were deafened prior to hearing onset by systemic aminoglycoside injections. Auditory brainstem responses showed profound hearing loss by 16-18 days postnatal. At ~ 4 weeks of age, AAV2-GFP (green fluorescent protein), AAV5-GFP, AAV2-hBDNF, or AAV5-hGDNF (glial-derived neurotrophic factor) was injected through the round window unilaterally. For GFP immunofluorescence, animals were studied ~ 4 weeks post-injection to assess cell types transfected and their distributions. AAV2-GFP immunofluorescence demonstrated strong expression of the GFP reporter gene in residual inner (IHCs), outer hair cells (OHCs), inner pillar cells, and in some SG neurons throughout the cochlea. AAV5-GFP elicited robust transduction of IHCs and some SG neurons, but few OHCs and supporting cells. After AAV-neurotrophic factor injections, animals were studied ~ 3 months post-injection to evaluate neural survival. AAV5-hGDNF elicited a modest neurotrophic effect, with 6 % higher SG density, but had no trophic effect on radial nerve fiber survival, and undesirable ectopic fiber sprouting occurred. AAV2-hBDNF elicited a similar 6 % increase in SG survival, but also resulted in greatly improved radial nerve fiber survival, with no ectopic fiber sprouting. A further study assessed whether AAV2-hBDNF neurotrophic effects would persist over longer post-injection periods. Animals examined 6 months after virus injection showed substantial neurotrophic effects, with 14 % higher SG density and greatly improved radial nerve fiber survival. Our results suggest that AAV-neurotrophin gene therapy can elicit expression of physiological concentrations of neurotrophins in the cochlea, supporting improved SG neuronal and radial nerve fiber survival while avoiding undesirable side effects. These studies also demonstrate the potential for application of cochlear gene therapy in a large mammalian cochlea comparable to the human cochlea and in an animal model of congenital/early acquired deafness.
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321
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Tucci DL, Doherty JK. Contributions of Contemporary Human Temporal Bone Histopathology to Clinical Otology. Otolaryngol Head Neck Surg 2019; 161:725-733. [PMID: 31359831 DOI: 10.1177/0194599819863368] [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: 11/16/2022]
Abstract
Contemporary techniques have greatly enhanced the contributions of human temporal bone (HTB) histopathology to our understanding of the mechanisms of human otologic disease and disease treatment. Herein, we review some of the most salient contributions of this research to disease management. The field of HTB histopathology is challenged by limited resources as applies to trained investigators, infrastructure, and well-equipped laboratories. This research provides insights into clinical otology that cannot be obtained by any other means. Measures should be taken to preserve and extend the contributions of HTB research.
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Affiliation(s)
- Debara L Tucci
- Department of Head and Neck Surgery & Communication Sciences, Duke University School of Medicine, Durham, North Carolina, USA
| | - Joni K Doherty
- Rick and Tina Caruso Department of Otolaryngology-Head & Neck Surgery, Keck Medicine of University of Southern California, Los Angeles, California, USA
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322
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Wang Y, Qu Y, Chen X, Zhang P, Su D, Wang L, Yang F, Yang J. Effects of D-methionine in mice with noise-induced hearing loss mice. J Int Med Res 2019; 47:3874-3885. [PMID: 31327277 PMCID: PMC6726779 DOI: 10.1177/0300060519860679] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective To study the effects of D-methionine in a mouse model of noise-induced hearing loss (NIHL). Methods We investigated changes in auditory function and microscopic cochlear structure in a mouse model of NIHL, and carried out 4-hydroxynonenal (4-HNE) immunostaining and terminal deoxynucleotidyl transferase dUTP nick-end labeling, and examined expression levels of connexins 26 and 30 by western blot. Results The auditory brainstem response threshold was significantly increased by noise exposure. Noise exposure also damaged the inner and particularly the outer hair cells in the cochlear basement membrane, while histochemistry demonstrated only scattered loss of hair cells in the basement membrane in mice treated with D-methionine before or after noise exposure. D-methionine inhibited apoptosis in the cochlear basement membrane, stria vascularis, and spiral ligament. 4-HNE expression in the basement membrane, stria vascularis, and spiral collateral ligament was increased by noise exposure, but this increase was attenuated by D-methionine. Connexin 26 and connexin 30 expression levels were reduced by noise exposure, and this effect was similarly attenuated by D-methionine administered either before or after noise exposure. Conclusion D-methionine administered before or after noise exposure could rescue NIHL by protecting cochlear morphology, inhibiting apoptosis, and maintaining connexin 26 and 30 expression.
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Affiliation(s)
- Yanru Wang
- 1 Department of Otorhinolaryngology, The 980th Hospital of the Joint Logistics Support Force of the Chinese Peopole's Liberation Army, Shijiazhuang, China
| | - Yan Qu
- 2 Department of Otorhinolaryngology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xuzhen Chen
- 1 Department of Otorhinolaryngology, The 980th Hospital of the Joint Logistics Support Force of the Chinese Peopole's Liberation Army, Shijiazhuang, China
| | - Pu Zhang
- 2 Department of Otorhinolaryngology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Dan Su
- 2 Department of Otorhinolaryngology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Li Wang
- 2 Department of Otorhinolaryngology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Feifei Yang
- 2 Department of Otorhinolaryngology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Jiangdong Yang
- 2 Department of Otorhinolaryngology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
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323
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Ji L, Lee HJ, Wan G, Wang GP, Zhang L, Sajjakulnukit P, Schacht J, Lyssiotis CA, Corfas G. Auditory metabolomics, an approach to identify acute molecular effects of noise trauma. Sci Rep 2019; 9:9273. [PMID: 31239523 PMCID: PMC6592947 DOI: 10.1038/s41598-019-45385-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 05/29/2019] [Indexed: 11/26/2022] Open
Abstract
Animal-based studies have provided important insights into the structural and functional consequences of noise exposure on the cochlea. Yet, less is known about the molecular mechanisms by which noise induces cochlear damage, particularly at relatively low exposure levels. While there is ample evidence that noise exposure leads to changes in inner ear metabolism, the specific effects of noise exposure on the cochlear metabolome are poorly understood. In this study we applied liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS)-based metabolomics to analyze the effects of noise on the mouse inner ear. Mice were exposed to noise that induces temporary threshold shifts, synaptopathy and permanent hidden hearing loss. Inner ears were harvested immediately after exposure and analyzed by targeted metabolomics for the relative abundance of 220 metabolites across the major metabolic pathways in central carbon metabolism. We identified 40 metabolites differentially affected by noise. Our approach detected novel noise-modulated metabolites and pathways, as well as some already linked to noise exposure or cochlear function such as neurotransmission and oxidative stress. Furthermore, it showed that metabolic effects of noise on the inner ear depend on the intensity and duration of exposure. Collectively, our results illustrate that metabolomics provides a powerful approach for the characterization of inner ear metabolites affected by auditory trauma. This type of information could lead to the identification of drug targets and novel therapies for noise-induced hearing loss.
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Affiliation(s)
- Lingchao Ji
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Ho-Joon Lee
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Guoqiang Wan
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Guo-Peng Wang
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Li Zhang
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Peter Sajjakulnukit
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Jochen Schacht
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA
| | - Costas A Lyssiotis
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 48109, Ann Arbor, USA.
| | - Gabriel Corfas
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan Medical School, 48109, Ann Arbor, USA.
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324
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Kaur T, Clayman AC, Nash AJ, Schrader AD, Warchol ME, Ohlemiller KK. Lack of Fractalkine Receptor on Macrophages Impairs Spontaneous Recovery of Ribbon Synapses After Moderate Noise Trauma in C57BL/6 Mice. Front Neurosci 2019; 13:620. [PMID: 31263398 PMCID: PMC6585312 DOI: 10.3389/fnins.2019.00620] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/29/2019] [Indexed: 01/08/2023] Open
Abstract
Noise trauma causes loss of synaptic connections between cochlear inner hair cells (IHCs) and the spiral ganglion neurons (SGNs). Such synaptic loss can trigger slow and progressive degeneration of SGNs. Macrophage fractalkine signaling is critical for neuron survival in the injured cochlea, but its role in cochlear synaptopathy is unknown. Fractalkine, a chemokine, is constitutively expressed by SGNs and signals via its receptor CX3CR1 that is expressed on macrophages. The present study characterized the immune response and examined the function of fractalkine signaling in degeneration and repair of cochlear synapses following noise trauma. Adult mice wild type, heterozygous and knockout for CX3CR1 on a C57BL/6 background were exposed for 2 h to an octave band noise at 90 dB SPL. Noise exposure caused temporary shifts in hearing thresholds without any evident loss of hair cells in CX3CR1 heterozygous mice that have intact fractalkine signaling. Enhanced macrophage migration toward the IHC-synaptic region was observed immediately after exposure in all genotypes. Synaptic immunolabeling revealed a rapid loss of ribbon synapses throughout the basal turn of the cochlea of all genotypes. The damaged synapses spontaneously recovered in mice with intact CX3CR1. However, CX3CR1 knockout (KO) animals displayed enhanced synaptic degeneration that correlated with attenuated suprathreshold neural responses at higher frequencies. Exposed CX3CR1 KO mice also exhibited increased loss of IHCs and SGN cell bodies compared to exposed heterozygous mice. These results indicate that macrophages can promote repair of damaged synapses after moderate noise trauma and that repair requires fractalkine signaling.
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Affiliation(s)
- Tejbeer Kaur
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States
| | - Anna C Clayman
- Program in Audiology and Communication Sciences, Washington University School of Medicine, St. Louis, MO, United States
| | - Andrew J Nash
- Program in Audiology and Communication Sciences, Washington University School of Medicine, St. Louis, MO, United States
| | - Angela D Schrader
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States
| | - Mark E Warchol
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States
| | - Kevin K Ohlemiller
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States.,Program in Audiology and Communication Sciences, Washington University School of Medicine, St. Louis, MO, United States
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325
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Abbas L, Rivolta MN. The use of animal models to study cell transplantation in neuropathic hearing loss. Hear Res 2019; 377:72-87. [DOI: 10.1016/j.heares.2019.03.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/12/2019] [Accepted: 03/15/2019] [Indexed: 01/29/2023]
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326
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Bramhall N, Beach EF, Epp B, Le Prell CG, Lopez-Poveda EA, Plack CJ, Schaette R, Verhulst S, Canlon B. The search for noise-induced cochlear synaptopathy in humans: Mission impossible? Hear Res 2019; 377:88-103. [DOI: 10.1016/j.heares.2019.02.016] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/25/2019] [Accepted: 02/28/2019] [Indexed: 10/27/2022]
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327
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328
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Song Z, Laureano AS, Patel K, Yip S, Jadali A, Kwan KY. Single-Cell Fluorescence Analysis of Pseudotemporal Ordered Cells Provides Protein Expression Dynamics for Neuronal Differentiation. Front Cell Dev Biol 2019; 7:87. [PMID: 31192206 PMCID: PMC6549217 DOI: 10.3389/fcell.2019.00087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/08/2019] [Indexed: 12/31/2022] Open
Abstract
Stem cell replacement therapy is a potential method for repopulating lost spiral ganglion neurons (SGNs) in the inner ear. Efficacy of cell replacement relies on proper differentiation. Defining the dynamic expression of different transcription factors essential for neuronal differentiation allows us to monitor the progress and determine when the protein functions in differentiating stem cell cultures. Using immortalized multipotent otic progenitors (iMOPs) as a cellular system for SGN differentiation, a method for determining dynamic protein expression from heterogeneous cultures was developed. iMOP-derived neurons were identified and ordered by increasing neurite lengths to create a pseudotime course that reflects the differentiation trajectory. The fluorescence intensities of transcription factors SOX2 and NEUROD1 from individual pseudotemporally ordered cells were measured. Individual cells were grouped by K-means clustering and the mean fluorescence intensity for each cluster determined. Curve fit of the mean fluorescence represented the protein expression dynamics in differentiating cells. The method provides information about protein expression dynamics in differentiating stem cell cultures.
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Affiliation(s)
- Zhichao Song
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, United States.,Stem Cell Research Center and Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ, United States
| | - Alejandra S Laureano
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, United States.,Stem Cell Research Center and Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ, United States
| | - Kishan Patel
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, United States
| | - Sylvia Yip
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, United States
| | - Azadeh Jadali
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, United States.,Stem Cell Research Center and Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ, United States
| | - Kelvin Y Kwan
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, United States.,Stem Cell Research Center and Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ, United States
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329
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Fischer N, Johnson Chacko L, Glueckert R, Schrott-Fischer A. Age-Dependent Changes in the Cochlea. Gerontology 2019; 66:33-39. [DOI: 10.1159/000499582] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 03/13/2019] [Indexed: 11/19/2022] Open
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330
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McLaughlin SA, Thorne JC, Jirikowic T, Waddington T, Lee AKC, Astley Hemingway SJ. Listening Difficulties in Children With Fetal Alcohol Spectrum Disorders: More Than a Problem of Audibility. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2019; 62:1532-1548. [PMID: 31039324 DOI: 10.1044/2018_jslhr-h-18-0359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Purpose Data from standardized caregiver questionnaires indicate that children with fetal alcohol spectrum disorders (FASDs) frequently exhibit atypical auditory behaviors, including reduced responsivity to spoken stimuli. Another body of evidence suggests that prenatal alcohol exposure may result in auditory dysfunction involving loss of audibility (i.e., hearing loss) and/or impaired processing of clearly audible, "suprathreshold" sounds necessary for sound-in-noise listening. Yet, the nexus between atypical auditory behavior and underlying auditory dysfunction in children with FASDs remains largely unexplored. Method To investigate atypical auditory behaviors in FASDs and explore their potential physiological bases, we examined clinical data from 325 children diagnosed with FASDs at the University of Washington using the FASD 4-Digit Diagnostic Code. Atypical behaviors reported on the "auditory filtering" domain of the Short Sensory Profile were assessed to document their prevalence across FASD diagnoses and explore their relationship to reported hearing loss and/or central nervous system measures of cognition, attention, and language function that may indicate suprathreshold processing deficits. Results Atypical auditory behavior was reported among 80% of children with FASDs, a prevalence that did not vary by FASD diagnostic severity or hearing status but was positively correlated with attention-deficit/hyperactivity disorder. In contrast, hearing loss was documented in the clinical records of 40% of children with fetal alcohol syndrome (FAS; a diagnosis on the fetal alcohol spectrum characterized by central nervous system dysfunction, facial dysmorphia, and growth deficiency), 16-fold more prevalent than for those with less severe FASDs (2.4%). Reported hearing loss was significantly associated with physical features characteristic of FAS. Conclusion Children with FAS but not other FASDs may be at a particular risk for hearing loss. However, listening difficulties in the absence of hearing loss-presumably related to suprathreshold processing deficits-are prevalent across the entire fetal alcohol spectrum. The nature and impact of both listening difficulties and hearing loss in FASDs warrant further investigation.
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Affiliation(s)
- Susan A McLaughlin
- Institute for Learning & Brain Sciences, University of Washington, Seattle
| | - John C Thorne
- Department of Speech & Hearing Sciences, University of Washington, Seattle
| | - Tracy Jirikowic
- Division of Occupational Therapy, Department of Rehabilitation Medicine, School of Medicine, University of Washington, Seattle
| | - Tiffany Waddington
- Institute for Learning & Brain Sciences, University of Washington, Seattle
| | - Adrian K C Lee
- Institute for Learning & Brain Sciences, University of Washington, Seattle
- Department of Speech & Hearing Sciences, University of Washington, Seattle
| | - Susan J Astley Hemingway
- Department of Epidemiology, University of Washington, Seattle
- Department of Pediatrics, University of Washington, Seattle
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331
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Ma Y, Wise AK, Shepherd RK, Richardson RT. New molecular therapies for the treatment of hearing loss. Pharmacol Ther 2019; 200:190-209. [PMID: 31075354 DOI: 10.1016/j.pharmthera.2019.05.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/02/2019] [Indexed: 12/11/2022]
Abstract
An estimated 466 million people suffer from hearing loss worldwide. Sensorineural hearing loss is characterized by degeneration of key structures of the sensory pathway in the cochlea such as the sensory hair cells, the primary auditory neurons and their synaptic connection to the hair cells - the ribbon synapse. Various strategies to protect or regenerate these sensory cells and structures are the subject of intensive research. Yet despite recent advances in our understandings of the capacity of the cochlea for repair and regeneration there are currently no pharmacological or biological interventions for hearing loss. Current research focusses on localized cochlear drug, gene and cell-based therapies. One of the more promising drug-based therapies is based on neurotrophic factors for the repair of the ribbon synapse after noise exposure, as well as preventing loss of primary auditory neurons and regrowth of the auditory neuron fibers after severe hearing loss. Drug therapy delivery technologies are being employed to address the specific needs of neurotrophin and other therapies for hearing loss that include the need for high doses, long-term delivery, localised or cell-specific targeting and techniques for their safe and efficacious delivery to the cochlea. Novel biomaterials are enabling high payloads of drugs to be administered to the cochlea with subsequent slow-release properties that are proving to be beneficial for treating hearing loss. In parallel, new gene therapy technologies are addressing the need for cell specificity and high efficacy for the treatment of both genetic and acquired hearing loss with promising reports of hearing recovery. Some biomaterials and cell therapies are being used in conjunction with the cochlear implant ensuring therapeutic benefit to the primary neurons during electrical stimulation. This review will introduce the auditory system, hearing loss and the potential for repair and regeneration in the cochlea. Drug delivery to the cochlea will then be reviewed, with a focus on new biomaterials, gene therapy technologies, cell therapy and the use of the cochlear implant as a vehicle for drug delivery. With the current pre-clinical research effort into therapies for hearing loss, including clinical trials for gene therapy, the future for the treatment for hearing loss is looking bright.
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Affiliation(s)
- Yutian Ma
- Bionics Institute, East Melbourne, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Australia; University of Melbourne, Department of Chemical Engineering, Parkville, Victoria, Australia
| | - Andrew K Wise
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Robert K Shepherd
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Rachael T Richardson
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia.
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332
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Abstract
Cholinergic efferent neurons originating in the brainstem innervate the acoustico-lateralis organs (inner ear, lateral line) of vertebrates. These release acetylcholine (ACh) to inhibit hair cells through activation of calcium-dependent potassium channels. In the mammalian cochlea, ACh shunts and suppresses outer hair cell (OHC) electromotility, reducing the essential amplification of basilar membrane motion. Consequently, medial olivocochlear neurons that inhibit OHCs reduce the sensitivity and frequency selectivity of afferent neurons driven by cochlear vibration of inner hair cells (IHCs). The cholinergic synapse on hair cells involves an unusual ionotropic ACh receptor, and a near-membrane postsynaptic cistern. Lateral olivocochlear (LOC) neurons modulate type I afferents by still-to-be-defined synaptic mechanisms. Olivocochlear neurons can be activated by a reflex arc that includes the auditory nerve and projections from the cochlear nucleus. They are also subject to modulation by higher-order central auditory interneurons. Through its actions on cochlear hair cells, afferent neurons, and higher centers, the olivocochlear system protects against age-related and noise-induced hearing loss, improves signal coding in noise under certain conditions, modulates selective attention to sensory stimuli, and influences sound localization.
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Affiliation(s)
- Paul Albert Fuchs
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2195
| | - Amanda M Lauer
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2195
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333
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Moore BCJ, Sęk AP, Füllgrabe C. Envelope regularity discrimination. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:2861. [PMID: 31153343 DOI: 10.1121/1.5100620] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
The ability to discriminate irregular from regular amplitude modulation was assessed using the "envelope regularity discrimination" test. The amount of irregularity was parametrically varied and quantified by an "irregularity index." Normative data were gathered for young subjects with normal audiometric thresholds. Parameters varied were the carrier and modulation frequencies, fc and fm, and the baseline modulation index, m. All tests were performed using a background threshold-equalizing noise. The main findings were (1) using fc = 4000 Hz, fm = 8 Hz, and m = 0.3, performance improved over the first two threshold runs and then remained roughly stable, and there was a high correlation between thresholds obtained at 80 dB sound pressure level (SPL) and at 20 dB sensation level; (2) using fm = 8 Hz and m = 0.3 with a level of 80 dB SPL, thresholds did not vary significantly across fc = 1000, 2000, and 4000 Hz; (3) using fm = 8 Hz and fc = 4000 Hz with a level of 80 dB SPL, thresholds did not vary significantly for m from 0.2 to 0.5; and (4) using m = 0.3 and fc = 4000 Hz with a level of 80 dB SPL, thresholds improved with increasing fm from 2 to 16 Hz. For all conditions, there was substantial individual variability, probably resulting from differences in "processing efficiency."
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Affiliation(s)
- Brian C J Moore
- Department of Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, United Kingdom
| | - Aleksander P Sęk
- Institute of Acoustics, Faculty of Physics, Adam Mickiewicz University, Poznań, Poland
| | - Christian Füllgrabe
- School of Sport, Exercise and Health Sciences, Loughborough University, Ashby Road, Loughborough, Leicestershire LE11 3TU, United Kingdom
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334
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Parthasarathy A, Bartlett EL, Kujawa SG. Age-related Changes in Neural Coding of Envelope Cues: Peripheral Declines and Central Compensation. Neuroscience 2019; 407:21-31. [DOI: 10.1016/j.neuroscience.2018.12.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 12/22/2022]
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335
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A Cross-Sectional Questionnaire Study of Tinnitus Awareness and Impact in a Population of Adult Cochlear Implant Users. Ear Hear 2019; 40:135-142. [PMID: 29933258 PMCID: PMC6319580 DOI: 10.1097/aud.0000000000000601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Supplemental Digital Content is available in the text. Objectives: The primary aim was to identify the proportion of individuals within the adult cochlear implant population who are aware of tinnitus and those who report a negative impact from this perception, using a bespoke questionnaire designed to limit bias. A secondary aim was to use qualitative analysis of open-text responses to identify themes linked to tinnitus perception in this population. Design: A cross-sectional questionnaire study of a large clinical population who received an implant from Cambridge University Hospitals, United Kingdom. Results: Seventy-five percent of respondents reported tinnitus awareness. When impact scores for six areas of difficulty were ranked, 13% of individuals ranked tinnitus their primary concern and nearly a third ranked tinnitus in the top two positions. Tinnitus impact was not found to reduce with duration since implantation. The most common open-text responses were linked to a general improvement postimplantation and acute tinnitus alleviation specific to times when the device was in use. Conclusions: Tinnitus is a problem for a significant proportion of individuals with a cochlear implant. Clinicians, scientists, and cochlear implant manufacturers should be aware that management of tinnitus may be a greater priority for an implantee than difficulties linked to speech perception. Where a positive effect of implantation was reported, there was greater evidence for masking of tinnitus via the implant rather than reversal of maladaptive plasticity.
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336
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Regulation of Noise-Induced Loss of Serotonin Transporters with Resveratrol in a Rat Model Using 4-[ 18F]-ADAM/Small-Animal Positron Emission Tomography. Molecules 2019; 24:molecules24071344. [PMID: 30959762 PMCID: PMC6480549 DOI: 10.3390/molecules24071344] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/28/2019] [Accepted: 04/04/2019] [Indexed: 11/16/2022] Open
Abstract
Serotonin (5-HT) plays a crucial role in modulating the afferent fiber discharge rate in the inferior colliculus, auditory cortex, and other nuclei of the ascending auditory system. Resveratrol, a natural polyphenol phytoalexin, can inhibit serotonin transporters (SERT) to increase synaptic 5-HT levels. In this study, we investigated the effects of resveratrol on noise-induced damage in the serotonergic system. Male Sprague-Dawley rats were anaesthetized and exposed to an 8-kHz tone at 116 dB for 3.5 h. Resveratrol (30 mg/kg, intraperitoneal injection [IP]) and citalopram (20 mg/kg, IP), a specific SERT inhibitor used as a positive control, were administered once a day for four consecutive days, with the first treatment occurring 2 days before noise exposure. Auditory brainstem response testing and positron emission tomography (PET) with N,N-dimethyl-2-(2-amino-4-[18F]fluorophenylthio)benzylamine (4-[18F]-ADAM, a specific radioligand for SERT) were used to evaluate functionality of the auditory system and integrity of the serotonergic system, respectively, before and after noise exposure. Finally, immunohistochemistry was performed 1 day after the last PET scan. Our results indicate that noise-induced serotonergic fiber loss occurred in multiple brain regions including the midbrain, thalamus, hypothalamus, striatum, auditory cortex, and frontal cortex. This noise-induced damage to the serotonergic system was ameliorated in response to treatment with resveratrol and citalopram. However, noise exposure increased the hearing threshold in the rats regardless of drug treatment status. We conclude that resveratrol has protective effects against noise-induced loss of SERT.
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337
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Tawfik KO, Klepper K, Saliba J, Friedman RA. Advances in understanding of presbycusis. J Neurosci Res 2019; 98:1685-1697. [PMID: 30950547 DOI: 10.1002/jnr.24426] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 03/14/2019] [Accepted: 03/18/2019] [Indexed: 12/21/2022]
Abstract
The pathophysiology of age-related hearing loss (ARHL), or presbycusis, involves a complex interplay between environmental and genetic factors. The fundamental biomolecular mechanisms of ARHL have been well described, including the roles of membrane transport, reactive oxygen species, cochlear synaptopathy, vascular insults, hormones, and microRNA, to name a few. The genetic basis underlying these mechanisms remains under-investigated and poorly understood. The emergence of genome-wide association studies has allowed for the identification of specific groups of genes involved in ARHL. This review highlights recent advances in understanding of the pathogenesis of ARHL, the genetic basis underlying these processes and suggests future directions for research and potential therapeutic avenues.
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Affiliation(s)
- Kareem O Tawfik
- Division of Otolaryngology - Head & Neck Surgery, University of California San Diego School of Medicine, San Diego, California
| | - Kristin Klepper
- School of Medicine, University of California San Diego, La Jolla, California
| | - Joe Saliba
- Division of Otolaryngology - Head & Neck Surgery, University of California San Diego School of Medicine, San Diego, California
| | - Rick A Friedman
- Division of Otolaryngology - Head & Neck Surgery, University of California San Diego School of Medicine, San Diego, California
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338
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Attenuation of adverse effects of noise induced hearing loss on adult neurogenesis and memory in rats by intervention with Adenosine A2A receptor agonist. Brain Res Bull 2019; 147:47-57. [DOI: 10.1016/j.brainresbull.2019.02.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/21/2019] [Accepted: 02/07/2019] [Indexed: 01/11/2023]
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339
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No Reliable Association Between Recreational Noise Exposure and Threshold Sensitivity, Distortion Product Otoacoustic Emission Amplitude, or Word-in-Noise Performance in a College Student Population. Ear Hear 2019. [PMID: 29543608 DOI: 10.1097/aud.0000000000000575] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
OBJECTIVES The purpose of this study was to evaluate the relationship between recreational sound exposure and potentially undiagnosed or subclinical hearing loss by assessing sound exposure history, threshold sensitivity, distortion product otoacoustic emission (DPOAE) amplitudes, and performance on the words-in-noise (WIN) test. DESIGN Survey data were collected from 74 adult participants (14 male and 60 female), 18 to 27 years of age, recruited via advertisements posted throughout the University of Florida campus. Of these participants, 70 completed both the survey and the additional functional test battery, and their preferred listening level was measured in a laboratory setting. RESULTS There were statistically significant relationships between hearing thresholds and DPOAE amplitude. In contrast, performance on the WIN was not reliably related to threshold sensitivity within this cohort with largely normal hearing. The two most common exposures included bars or dance clubs, followed by music player use. There were no statistically significant relationships between individual or composite measures of recreational sound exposure, including preferred listening level, years of music player use, number of reported sound exposures, previous impulse noise exposure, or previous noise-induced change in hearing, and functional measures including threshold, DPOAE amplitude, and WIN measures. Some subjects were highly consistent in listening level preferences, while others were more variable from song to song. CONCLUSIONS No reliable relationships between common recreational sound exposure or previous noise-induced changes in hearing were found during analysis of threshold sensitivity, DPOAE amplitude, or WIN performance in this cohort. However, the study sample was predominantly female and Caucasian, which limits generalizability of the results.
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340
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Liu W, Wang X, Wang M, Wang H. Protection of Spiral Ganglion Neurons and Prevention of Auditory Neuropathy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1130:93-107. [DOI: 10.1007/978-981-13-6123-4_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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341
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Ridley CL, Kopun JG, Neely ST, Gorga MP, Rasetshwane DM. Using Thresholds in Noise to Identify Hidden Hearing Loss in Humans. Ear Hear 2019; 39:829-844. [PMID: 29337760 PMCID: PMC6046280 DOI: 10.1097/aud.0000000000000543] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Recent animal studies suggest that noise-induced synaptopathy may underlie a phenomenon that has been labeled hidden hearing loss (HHL). Noise exposure preferentially damages low spontaneous-rate auditory nerve fibers, which are involved in the processing of moderate- to high-level sounds and are more resistant to masking by background noise. Therefore, the effect of synaptopathy may be more evident in suprathreshold measures of auditory function, especially in the presence of background noise. The purpose of this study was to develop a statistical model for estimating HHL in humans using thresholds in noise as the outcome variable and measures that reflect the integrity of sites along the auditory pathway as explanatory variables. Our working hypothesis is that HHL is evident in the portion of the variance observed in thresholds in noise that is not dependent on thresholds in quiet, because this residual variance retains statistical dependence on other measures of suprathreshold function. DESIGN Study participants included 13 adults with normal hearing (≤15 dB HL) and 20 adults with normal hearing at 1 kHz and sensorineural hearing loss at 4 kHz (>15 dB HL). Thresholds in noise were measured, and the residual of the correlation between thresholds in noise and thresholds in quiet, which we refer to as thresholds-in-noise residual, was used as the outcome measure for the model. Explanatory measures were as follows: (1) auditory brainstem response (ABR) waves I and V amplitudes; (2) electrocochleographic action potential and summating potential amplitudes; (3) distortion product otoacoustic emissions level; and (4) categorical loudness scaling. All measurements were made at two frequencies (1 and 4 kHz). ABR and electrocochleographic measurements were made at 80 and 100 dB peak equivalent sound pressure level, while wider ranges of levels were tested during distortion product otoacoustic emission and categorical loudness scaling measurements. A model relating the thresholds-in-noise residual and the explanatory measures was created using multiple linear regression analysis. RESULTS Predictions of thresholds-in-noise residual using the model accounted for 61% (p < 0.01) and 48% (p < 0.01) of the variance in the measured thresholds-in-noise residual at 1 and 4 kHz, respectively. CONCLUSIONS Measures of thresholds in noise, the summating potential to action potential ratio, and ABR waves I and V amplitudes may be useful for the prediction of HHL in humans. With further development, our approach of quantifying HHL by the variance that remains in suprathreshold measures of auditory function after removing the variance due to thresholds in quiet, together with our statistical modeling, may provide a quantifiable and verifiable estimate of HHL in humans with normal hearing and with hearing loss. The current results are consistent with the view that inner hair cell and auditory nerve pathology may underlie suprathreshold auditory performance.
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Affiliation(s)
- Courtney L. Ridley
- Center for Hearing Research, Boys Town National Research Hospital, 555 North 30 St, Omaha, Nebraska 68131, USA
- Department of Speech, Language, and Hearing Sciences, University of Florida, 1225 Center Drive, Gainesville, FL 32610, USA
| | - Judy G. Kopun
- Center for Hearing Research, Boys Town National Research Hospital, 555 North 30 St, Omaha, Nebraska 68131, USA
| | - Stephen T. Neely
- Center for Hearing Research, Boys Town National Research Hospital, 555 North 30 St, Omaha, Nebraska 68131, USA
| | - Michael P. Gorga
- Center for Hearing Research, Boys Town National Research Hospital, 555 North 30 St, Omaha, Nebraska 68131, USA
| | - Daniel M. Rasetshwane
- Center for Hearing Research, Boys Town National Research Hospital, 555 North 30 St, Omaha, Nebraska 68131, USA
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Bharadwaj HM, Mai AR, Simpson JM, Choi I, Heinz MG, Shinn-Cunningham BG. Non-Invasive Assays of Cochlear Synaptopathy - Candidates and Considerations. Neuroscience 2019; 407:53-66. [PMID: 30853540 DOI: 10.1016/j.neuroscience.2019.02.031] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 02/21/2019] [Accepted: 02/25/2019] [Indexed: 12/31/2022]
Abstract
Studies in multiple species, including in post-mortem human tissue, have shown that normal aging and/or acoustic overexposure can lead to a significant loss of afferent synapses innervating the cochlea. Hypothetically, this cochlear synaptopathy can lead to perceptual deficits in challenging environments and can contribute to central neural effects such as tinnitus. However, because cochlear synaptopathy can occur without any measurable changes in audiometric thresholds, synaptopathy can remain hidden from standard clinical diagnostics. To understand the perceptual sequelae of synaptopathy and to evaluate the efficacy of emerging therapies, sensitive and specific non-invasive measures at the individual patient level need to be established. Pioneering experiments in specific mice strains have helped identify many candidate assays. These include auditory brainstem responses, the middle-ear muscle reflex, envelope-following responses, and extended high-frequency audiograms. Unfortunately, because these non-invasive measures can be also affected by extraneous factors other than synaptopathy, their application and interpretation in humans is not straightforward. Here, we systematically examine six extraneous factors through a series of interrelated human experiments aimed at understanding their effects. Using strategies that may help mitigate the effects of such extraneous factors, we then show that these suprathreshold physiological assays exhibit across-individual correlations with each other indicative of contributions from a common physiological source consistent with cochlear synaptopathy. Finally, we discuss the application of these assays to two key outstanding questions, and discuss some barriers that still remain. This article is part of a Special Issue entitled: Hearing Loss, Tinnitus, Hyperacusis, Central Gain.
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Affiliation(s)
- Hari M Bharadwaj
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN.
| | - Alexandra R Mai
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN
| | - Jennifer M Simpson
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN
| | - Inyong Choi
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA
| | - Michael G Heinz
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN
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343
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Pienkowski M. Prolonged Exposure of CBA/Ca Mice to Moderately Loud Noise Can Cause Cochlear Synaptopathy but Not Tinnitus or Hyperacusis as Assessed With the Acoustic Startle Reflex. Trends Hear 2019. [PMID: 29532738 PMCID: PMC5858683 DOI: 10.1177/2331216518758109] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hearing loss changes the auditory brain, sometimes maladaptively. When deprived of cochlear input, central auditory neurons become more active spontaneously and begin to respond more strongly and synchronously to better preserved sound frequencies. This spontaneous and sound-evoked central hyperactivity has been postulated to trigger tinnitus and hyperacusis, respectively. Localized hyperactivity has also been observed after long-term exposure to noise levels that do not damage the cochlea. Adult animals exposed to bands of nondamaging noise exhibited suppressed spontaneous and sound-evoked activity in the area of primary auditory cortex (A1) stimulated by the exposure band but had increased spontaneous and evoked activity in neighboring A1 areas. We hypothesized that the cortically suppressed frequencies should for some time after exposure be perceived as less loud than before (hypoacusis), whereas the hyperactivity outside of the exposure band might lead to frequency-specific hyperacusis or tinnitus. To investigate this, adult CBA/Ca mice were exposed for >2 months to 8 to 16 kHz noise at 70 or 75 dB sound pressure level and tested for hypo-/hyperacusis and tinnitus using tone and gap prepulse inhibition of the acoustic startle reflex. Auditory brainstem responses and distortion product otoacoustic emissions showed evidence of cochlear synaptopathy after exposure at 75 but not 70 dB, putting a lower bound on damaging noise levels for CBA/Ca mice. Contrary to hypothesis, neither exposure significantly shifted startle results from baseline. These negative findings nevertheless have implications for startle test methodology and for the putative role of central hyperactivity in hyperacusis and tinnitus.
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Affiliation(s)
- Martin Pienkowski
- 1 Osborne College of Audiology, Salus University, Elkins Park, PA, USA
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344
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Vercammen C, Goossens T, Undurraga J, Wouters J, van Wieringen A. Electrophysiological and Behavioral Evidence of Reduced Binaural Temporal Processing in the Aging and Hearing Impaired Human Auditory System. Trends Hear 2019; 22:2331216518785733. [PMID: 30022734 PMCID: PMC6053861 DOI: 10.1177/2331216518785733] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A person’s ability to process temporal fine structure information is
indispensable for speech understanding. As speech understanding typically
deteriorates throughout adult life, this study aimed to disentangle age and
hearing impairment (HI)-related changes in binaural temporal processing. This
was achieved by examining neural and behavioral processing of interaural phase
differences (IPDs). Neural IPD processing was studied electrophysiologically
through steady-state activity in the electroencephalogram evoked by periodic
changes in IPDs over time, embedded in the temporal fine structure of acoustic
stimulation. In addition, behavioral IPD discrimination thresholds were
determined for the same stimuli. To disentangle potential effects of age from
those of HI, both measures were applied to six participant groups: young,
middle-aged, and older persons, with either normal hearing or sensorineural HI.
All participants passed a cognitive screening, and stimulus audibility was
controlled for in participants with HI. The results demonstrated that HI changes
neural processing of binaural temporal information for all age-groups included
in this study. These outcomes were revealed, superimposed on age-related changes
that emerge between young adulthood and middle age. Poorer neural outcomes were
also associated with poorer behavioral performance, even though the behavioral
IPD discrimination thresholds were affected by age rather than by HI. The neural
outcomes of this study are the first to evidence and disentangle the dual load
of age and HI on binaural temporal processing. These results could be a valuable
first step toward future research on rehabilitation.
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Affiliation(s)
- Charlotte Vercammen
- 1 Department of Neurosciences, Research Group Experimental Oto-Rhino-Laryngology, KU Leuven-University of Leuven, Belgium
| | - Tine Goossens
- 1 Department of Neurosciences, Research Group Experimental Oto-Rhino-Laryngology, KU Leuven-University of Leuven, Belgium
| | - Jaime Undurraga
- 2 Department of Linguistics, The Australian Hearing Hub, Macquarie University, Sydney, Australia.,3 Ear Institute, University College London, London, UK
| | - Jan Wouters
- 1 Department of Neurosciences, Research Group Experimental Oto-Rhino-Laryngology, KU Leuven-University of Leuven, Belgium
| | - Astrid van Wieringen
- 1 Department of Neurosciences, Research Group Experimental Oto-Rhino-Laryngology, KU Leuven-University of Leuven, Belgium
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345
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Heeringa AN, Köppl C. The aging cochlea: Towards unraveling the functional contributions of strial dysfunction and synaptopathy. Hear Res 2019; 376:111-124. [PMID: 30862414 DOI: 10.1016/j.heares.2019.02.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 02/01/2019] [Accepted: 02/26/2019] [Indexed: 10/27/2022]
Abstract
Strial dysfunction is commonly observed as a key consequence of aging in the cochlea. A large body of animal research, especially in the quiet-aged Mongolian gerbil, shows specific histopathological changes in the cochlear stria vascularis and the putatively corresponding effects on endocochlear potential and auditory nerve responses. However, recent work suggests that synaptopathy, or the loss of inner hair cell-auditory nerve fiber synapses, also presents as a consequence of aging. It is now believed that the loss of synapses is the earliest age-related degenerative event. The present review aims to integrate classic and novel research on age-related pathologies of the inner ear. First, we summarize current knowledge on age-related strial dysfunction and synaptopathy. We describe how these cochlear pathologies fit into the categories for presbyacusis, as first defined by Schuknecht in the '70s. Further, we discuss how strial dysfunction and synaptopathy affect sound coding by the auditory nerve and how they can be experimentally induced to study their specific contributions to age-related hearing deficits. As such, we aim to give an overview of the current literature on age-related cochlear pathologies and hope to inspire further research on the role of cochlear aging in age-related hearing deficits.
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Affiliation(s)
- Amarins N Heeringa
- Cluster of Excellence 'Hearing4all' and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, 26129, Oldenburg, Germany
| | - Christine Köppl
- Cluster of Excellence 'Hearing4all' and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, 26129, Oldenburg, Germany.
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346
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Sodium-activated potassium channels shape peripheral auditory function and activity of the primary auditory neurons in mice. Sci Rep 2019; 9:2573. [PMID: 30796290 PMCID: PMC6384918 DOI: 10.1038/s41598-019-39119-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/17/2019] [Indexed: 11/08/2022] Open
Abstract
Potassium (K+) channels shape the response properties of neurons. Although enormous progress has been made to characterize K+ channels in the primary auditory neurons, the molecular identities of many of these channels and their contributions to hearing in vivo remain unknown. Using a combination of RNA sequencing and single molecule fluorescent in situ hybridization, we localized expression of transcripts encoding the sodium-activated potassium channels KNa1.1 (SLO2.2/Slack) and KNa1.2 (SLO2.1/Slick) to the primary auditory neurons (spiral ganglion neurons, SGNs). To examine the contribution of these channels to function of the SGNs in vivo, we measured auditory brainstem responses in KNa1.1/1.2 double knockout (DKO) mice. Although auditory brainstem response (wave I) thresholds were not altered, the amplitudes of suprathreshold responses were reduced in DKO mice. This reduction in amplitude occurred despite normal numbers and molecular architecture of the SGNs and their synapses with the inner hair cells. Patch clamp electrophysiology of SGNs isolated from DKO mice displayed altered membrane properties, including reduced action potential thresholds and amplitudes. These findings show that KNa1 channel activity is essential for normal cochlear function and suggest that early forms of hearing loss may result from physiological changes in the activity of the primary auditory neurons.
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347
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Goossens T, Vercammen C, Wouters J, van Wieringen A. The association between hearing impairment and neural envelope encoding at different ages. Neurobiol Aging 2019; 74:202-212. [DOI: 10.1016/j.neurobiolaging.2018.10.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 09/11/2018] [Accepted: 10/04/2018] [Indexed: 10/28/2022]
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348
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Curhan SG, Willett WC, Grodstein F, Curhan GC. Longitudinal study of hearing loss and subjective cognitive function decline in men. Alzheimers Dement 2019; 15:525-533. [PMID: 30709794 DOI: 10.1016/j.jalz.2018.11.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/01/2018] [Accepted: 11/28/2018] [Indexed: 02/07/2023]
Abstract
INTRODUCTION We examined the relation between self-reported hearing loss, hearing aid use, and risk of subjective cognitive function (SCF) decline. METHODS We conducted an 8-year (2008-2016) longitudinal study of 10,107 men aged ≥62 years who reported their hearing status in 2006 and had no subjective cognitive concerns in 2008. Change in SCF scores was assessed by a 6-item questionnaire, and subjective decline was defined as new report of at least one SCF concern during follow-up. RESULTS Hearing loss was associated with higher risk of SCF decline. Compared with no hearing loss, the multivariable-adjusted relative risk (95% CI) of incident SCF decline was 1.30 (1.18, 1.42), 1.42 (1.26, 1.61), and 1.54 (1.22, 1.96) among men with mild, moderate, and severe hearing loss (no hearing aids), respectively (P-trend < .001). Among men with severe hearing loss who used hearing aids, the multivariable-adjusted relative risk (95% CI) was 1.37 (1.18, 1.60). DISCUSSION Hearing loss was associated with substantially higher risk of subsequent subjective cognitive decline in men.
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Affiliation(s)
- Sharon G Curhan
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
| | - Walter C Willett
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Francine Grodstein
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Gary C Curhan
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
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349
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Bullen A, Anderson L, Bakay W, Forge A. Localized disorganization of the cochlear inner hair cell synaptic region after noise exposure. Biol Open 2019; 8:bio.038547. [PMID: 30504133 PMCID: PMC6361218 DOI: 10.1242/bio.038547] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The prevalence and importance of hearing damage caused by noise levels not previously thought to cause permanent hearing impairment has become apparent in recent years. The damage to, and loss of, afferent terminals of auditory nerve fibres at the cochlear inner hair cell has been well established, but the effects of noise exposure and terminal loss on the inner hair cell are less known. Using three-dimensional structural studies in mice we have examined the consequences of afferent terminal damage on inner hair cell morphology and intracellular structure. We identified a structural phenotype in the pre-synaptic regions of these damaged hair cells that persists for four weeks after noise exposure, and demonstrates a specific dysregulation of the synaptic vesicle recycling pathway. We show evidence of a failure in regeneration of vesicles from small membrane cisterns in damaged terminals, resulting from a failure of separation of small vesicle buds from the larger cisternal membranes.
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350
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Langguth B, Elgoyhen AB, Cederroth CR. Therapeutic Approaches to the Treatment of Tinnitus. Annu Rev Pharmacol Toxicol 2019; 59:291-313. [DOI: 10.1146/annurev-pharmtox-010818-021556] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Tinnitus is a highly prevalent condition that is associated with hearing loss in most cases. In the absence of external stimuli, phantom perceptions of sounds emerge from alterations in neuronal activity within central auditory and nonauditory structures. Pioneering studies using lidocaine revealed that tinnitus is susceptible to pharmacological interventions. However, lidocaine is not effective in all patients, and no other drug has been identified with clear efficacy for the long-term treatment of tinnitus. In this review, we present recent advances in tinnitus research, including more detailed knowledge of its pathophysiology and involved neurotransmitter systems. Moreover, we summarize results from animal and clinical treatment studies as well as from studies that identified tinnitus as a side effect of pharmacological treatments. Finally, we focus on challenges in the development of pharmacological compounds for the treatment of tinnitus, namely the limitations of available animal models and of standardized clinical research methodologies.
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Affiliation(s)
- Berthold Langguth
- Department of Psychiatry and Psychotherapy, and Interdisciplinary Tinnitus Clinic, University of Regensburg, 93053 Regensburg, Germany
| | - Ana Belen Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres,” Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, 1121 Buenos Aires, Argentina
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