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Bramhall NF, McMillan GP. Perceptual Consequences of Cochlear Deafferentation in Humans. Trends Hear 2024; 28:23312165241239541. [PMID: 38738337 DOI: 10.1177/23312165241239541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024] Open
Abstract
Cochlear synaptopathy, a form of cochlear deafferentation, has been demonstrated in a number of animal species, including non-human primates. Both age and noise exposure contribute to synaptopathy in animal models, indicating that it may be a common type of auditory dysfunction in humans. Temporal bone and auditory physiological data suggest that age and occupational/military noise exposure also lead to synaptopathy in humans. The predicted perceptual consequences of synaptopathy include tinnitus, hyperacusis, and difficulty with speech-in-noise perception. However, confirming the perceptual impacts of this form of cochlear deafferentation presents a particular challenge because synaptopathy can only be confirmed through post-mortem temporal bone analysis and auditory perception is difficult to evaluate in animals. Animal data suggest that deafferentation leads to increased central gain, signs of tinnitus and abnormal loudness perception, and deficits in temporal processing and signal-in-noise detection. If equivalent changes occur in humans following deafferentation, this would be expected to increase the likelihood of developing tinnitus, hyperacusis, and difficulty with speech-in-noise perception. Physiological data from humans is consistent with the hypothesis that deafferentation is associated with increased central gain and a greater likelihood of tinnitus perception, while human data on the relationship between deafferentation and hyperacusis is extremely limited. Many human studies have investigated the relationship between physiological correlates of deafferentation and difficulty with speech-in-noise perception, with mixed findings. A non-linear relationship between deafferentation and speech perception may have contributed to the mixed results. When differences in sample characteristics and study measurements are considered, the findings may be more consistent.
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Affiliation(s)
- Naomi F Bramhall
- VA National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, Portland, OR, USA
- Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, OR, USA
| | - Garnett P McMillan
- VA National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, Portland, OR, USA
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Trevino M, Escabi C, Swanner H, Pawlowski K, Lobarinas E. No Reduction in the 226-Hz Probe Tone Acoustic Reflex Amplitude Following Severe Inner Hair Cell Loss in Chinchillas. J Assoc Res Otolaryngol 2022; 23:593-602. [PMID: 35902434 PMCID: PMC9613837 DOI: 10.1007/s10162-022-00861-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/04/2022] [Indexed: 11/30/2022] Open
Abstract
The relationship between the middle ear acoustic reflex (AR) and inner hair cell (IHC) loss is currently unknown. Given that IHC are believed to convey nearly all acoustic information to the central auditory nervous system, it has been assumed that loss of IHC would significantly impact the AR. To evaluate this relationship, we assessed the presence and amplitude of the AR in chinchillas before and after treatment with carboplatin, an anticancer drug that reliably and selectively destroys IHC in this species. Baseline measures of hearing sensitivity, including auditory brainstem response (ABR) thresholds and distortion product otoacoustic emissions (DPOAE), were assessed and then re-evaluated following carboplatin treatment. Post-carboplatin ABR thresholds and DPOAE were found to be unchanged or slightly elevated; results were consistent with published reports. Our main hypothesis was that loss of IHC would abolish the reflex or significantly reduce its amplitude. Contrary to our hypothesis, the ipsilateral 226-Hz AR continued to be reliably elicited following carboplatin treatment. Post-mortem histological analysis confirmed significant IHC loss (65-85 %), but no measurable loss of outer hair cells (OHCs). Given that loss of IHC alone does not significantly reduce the 226-Hz AR, our results suggest that few IHC are needed to maintain the 226-Hz AR response. These results suggest additional studies are needed to better understand the role of IHC in the reflex arc, present opportunities to further study the reflex pathway, and could change how we use the clinical AR as a potential diagnostic tool for IHC dysfunction, including those related to IHC synaptopathy.
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Affiliation(s)
- Monica Trevino
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
| | - Celia Escabi
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
| | - Hannah Swanner
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
| | - Karen Pawlowski
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
| | - Edward Lobarinas
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
- Callier Center for Communication Disorders, The University of Texas at Dallas, 1966 Inwood Road, Dallas, TX 75235 USA
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3
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Outer Hair Cell Function is Normal in βV Spectrin Knockout Mice. Hear Res 2022; 423:108564. [DOI: 10.1016/j.heares.2022.108564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 05/31/2022] [Accepted: 06/15/2022] [Indexed: 11/17/2022]
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Ripley S, Xia L, Zhang Z, Aiken SJ, Wang J. Animal-to-Human Translation Difficulties and Problems With Proposed Coding-in-Noise Deficits in Noise-Induced Synaptopathy and Hidden Hearing Loss. Front Neurosci 2022; 16:893542. [PMID: 35720689 PMCID: PMC9199355 DOI: 10.3389/fnins.2022.893542] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/22/2022] [Indexed: 12/26/2022] Open
Abstract
Noise induced synaptopathy (NIS) and hidden hearing loss (NIHHL) have been hot topic in hearing research since a massive synaptic loss was identified in CBA mice after a brief noise exposure that did not cause permanent threshold shift (PTS) in 2009. Based upon the amount of synaptic loss and the bias of it to synapses with a group of auditory nerve fibers (ANFs) with low spontaneous rate (LSR), coding-in-noise deficit (CIND) has been speculated as the major difficult of hearing in subjects with NIS and NIHHL. This speculation is based upon the idea that the coding of sound at high level against background noise relies mainly on the LSR ANFs. However, the translation from animal data to humans for NIS remains to be justified due to the difference in noise exposure between laboratory animals and human subjects in real life, the lack of morphological data and reliable functional methods to quantify or estimate the loss of the afferent synapses by noise. Moreover, there is no clear, robust data revealing the CIND even in animals with the synaptic loss but no PTS. In humans, both positive and negative reports are available. The difficulty in verifying CINDs has led a re-examination of the hypothesis that CIND is the major deficit associated with NIS and NIHHL, and the theoretical basis of this idea on the role of LSR ANFs. This review summarized the current status of research in NIS and NIHHL, with focus on the translational difficulty from animal data to human clinicals, the technical difficulties in quantifying NIS in humans, and the problems with the SR theory on signal coding. Temporal fluctuation profile model was discussed as a potential alternative for signal coding at high sound level against background noise, in association with the mechanisms of efferent control on the cochlea gain.
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Affiliation(s)
- Sara Ripley
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
| | - Li Xia
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
| | - Zhen Zhang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Steve J. Aiken
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
| | - Jian Wang
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
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Gauvin DV, McComb M, Tapp R, Yoder J, Zimmermann ZJ. Distortion Product Otoacoustic Emission Test is Not the Test to Use in Nonclinical Safety Assessment. Int J Toxicol 2022; 41:243-252. [PMID: 35443823 DOI: 10.1177/10915818221081841] [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: 10/18/2022]
Abstract
Ototoxicity and ocular toxicity screening are but two examples of specialty product lines that are often employed as Tier II or III nonclinical safety/hazard screening assessments. Compared to the regulatory guidelines that govern over standard toxicology or neurotoxicology programs, there is a paucity of regulatory strategies to address these specialized product lines. With respect to ototoxicity testing, we argue for the inclusion of the "least burdensome principles" adopted by the US FDA in providing the most pragmatic, efficient, and directed identification of potential harm to auditory function in the nonclinical safety arena. We argue for the exclusive use of the auditory brainstem response and the exclusion of the distortion product otoacoustic emissions (DPOAEs) in these Tiered II safety assessment programs. The inclusion of both are a burden on operational staff and, due to the extended episodes of anesthesia required to conduct both assays, this strategy poses a health and welfare concern for the selected animal species to be used. The DPOAE does not provide any sufficiently valid or reliable data above and beyond the gold standard ABR data, followed by complete oto-histopathology and cytocochleogram combination designs.
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Affiliation(s)
| | - Margaret McComb
- Neurobehavioral Studies, 537465Charles River Laboratories, Inc., Mattawan, Mattawan, MI, USA
| | - Rachel Tapp
- Neurobehavioral Studies, 537465Charles River Laboratories, Inc., Mattawan, Mattawan, MI, USA
| | - Joshua Yoder
- Neurobehavioral Studies, 537465Charles River Laboratories, Inc., Mattawan, Mattawan, MI, USA
| | - Zachary J Zimmermann
- Neurobehavioral Studies, 537465Charles River Laboratories, Inc., Mattawan, Mattawan, MI, USA
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Trevino M, Escabi CD, Zang A, Pawlowski K, Lobarinas E. Effect of Selective Carboplatin-Induced Inner Hair Cell Loss on Temporal Integration in Chinchillas. J Assoc Res Otolaryngol 2022; 23:379-389. [DOI: 10.1007/s10162-022-00843-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 03/02/2022] [Indexed: 11/30/2022] Open
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Bao J, Jegede SL, Hawks JW, Dade B, Guan Q, Middaugh S, Qiu Z, Levina A, Tsai TH. Detecting Cochlear Synaptopathy Through Curvature Quantification of the Auditory Brainstem Response. Front Cell Neurosci 2022; 16:851500. [PMID: 35356798 PMCID: PMC8959412 DOI: 10.3389/fncel.2022.851500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
The sound-evoked electrical compound potential known as auditory brainstem response (ABR) represents the firing of a heterogenous population of auditory neurons in response to sound stimuli, and is often used for clinical diagnosis based on wave amplitude and latency. However, recent ABR applications to detect human cochlear synaptopathy have led to inconsistent results, mainly due to the high variability of ABR wave-1 amplitude. Here, rather than focusing on the amplitude of ABR wave 1, we evaluated the use of ABR wave curvature to detect cochlear synaptic loss. We first compared four curvature quantification methods using simulated ABR waves, and identified that the cubic spline method using five data points produced the most accurate quantification. We next evaluated this quantification method with ABR data from an established mouse model with cochlear synaptopathy. The data clearly demonstrated that curvature measurement is more sensitive and consistent in identifying cochlear synaptic loss in mice compared to the amplitude and latency measurements. We further tested this curvature method in a different mouse model presenting with otitis media. The change in curvature profile due to middle ear infection in otitis media is different from the profile of mice with cochlear synaptopathy. Thus, our study suggests that curvature quantification can be used to address the current ABR variability issue, and may lead to additional applications in the clinic diagnosis of hearing disorders.
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Affiliation(s)
- Jianxin Bao
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
- *Correspondence: Jianxin Bao,
| | - Segun Light Jegede
- Department of Mathematical Sciences, Kent State University, Kent, OH, United States
| | - John W. Hawks
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
| | - Bethany Dade
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
| | - Qiang Guan
- Department of Computer Science, Kent State University, Kent, OH, United States
| | - Samantha Middaugh
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Ziyu Qiu
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
| | - Anna Levina
- Department of Mathematical Sciences, Kent State University, Kent, OH, United States
| | - Tsung-Heng Tsai
- Department of Mathematical Sciences, Kent State University, Kent, OH, United States
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Auerbach BD, Gritton HJ. Hearing in Complex Environments: Auditory Gain Control, Attention, and Hearing Loss. Front Neurosci 2022; 16:799787. [PMID: 35221899 PMCID: PMC8866963 DOI: 10.3389/fnins.2022.799787] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/18/2022] [Indexed: 12/12/2022] Open
Abstract
Listening in noisy or complex sound environments is difficult for individuals with normal hearing and can be a debilitating impairment for those with hearing loss. Extracting meaningful information from a complex acoustic environment requires the ability to accurately encode specific sound features under highly variable listening conditions and segregate distinct sound streams from multiple overlapping sources. The auditory system employs a variety of mechanisms to achieve this auditory scene analysis. First, neurons across levels of the auditory system exhibit compensatory adaptations to their gain and dynamic range in response to prevailing sound stimulus statistics in the environment. These adaptations allow for robust representations of sound features that are to a large degree invariant to the level of background noise. Second, listeners can selectively attend to a desired sound target in an environment with multiple sound sources. This selective auditory attention is another form of sensory gain control, enhancing the representation of an attended sound source while suppressing responses to unattended sounds. This review will examine both “bottom-up” gain alterations in response to changes in environmental sound statistics as well as “top-down” mechanisms that allow for selective extraction of specific sound features in a complex auditory scene. Finally, we will discuss how hearing loss interacts with these gain control mechanisms, and the adaptive and/or maladaptive perceptual consequences of this plasticity.
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Affiliation(s)
- Benjamin D. Auerbach
- Department of Molecular and Integrative Physiology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- *Correspondence: Benjamin D. Auerbach,
| | - Howard J. Gritton
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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Buran BN, McMillan GP, Keshishzadeh S, Verhulst S, Bramhall NF. Predicting synapse counts in living humans by combining computational models with auditory physiology. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:561. [PMID: 35105019 PMCID: PMC8800592 DOI: 10.1121/10.0009238] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 05/28/2023]
Abstract
Aging, noise exposure, and ototoxic medications lead to cochlear synapse loss in animal models. As cochlear function is highly conserved across mammalian species, synaptopathy likely occurs in humans as well. Synaptopathy is predicted to result in perceptual deficits including tinnitus, hyperacusis, and difficulty understanding speech-in-noise. The lack of a method for diagnosing synaptopathy in living humans hinders studies designed to determine if noise-induced synaptopathy occurs in humans, identify the perceptual consequences of synaptopathy, or test potential drug treatments. Several physiological measures are sensitive to synaptopathy in animal models including auditory brainstem response (ABR) wave I amplitude. However, it is unclear how to translate these measures to synaptopathy diagnosis in humans. This work demonstrates how a human computational model of the auditory periphery, which can predict ABR waveforms and distortion product otoacoustic emissions (DPOAEs), can be used to predict synaptic loss in individual human participants based on their measured DPOAE levels and ABR wave I amplitudes. Lower predicted synapse numbers were associated with advancing age, higher noise exposure history, increased likelihood of tinnitus, and poorer speech-in-noise perception. These findings demonstrate the utility of this modeling approach in predicting synapse counts from physiological data in individual human subjects.
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Affiliation(s)
- Brad N Buran
- Oregon Hearing Research Center (OHRC), Department of Otolaryngology-Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon, USA
| | - Garnett P McMillan
- Veterans Affairs (VA) Rehabilitation Research & Development Service (RR&D) National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System, Portland, Oregon, USA
| | - Sarineh Keshishzadeh
- Hearing Technology @ WAVES, Department of Information Technology, Ghent University, Belgium
| | - Sarah Verhulst
- Hearing Technology @ WAVES, Department of Information Technology, Ghent University, Belgium
| | - Naomi F Bramhall
- Veterans Affairs (VA) Rehabilitation Research & Development Service (RR&D) National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System, Portland, Oregon, USA
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Henry KS. Animal models of hidden hearing loss: Does auditory-nerve-fiber loss cause real-world listening difficulties? Mol Cell Neurosci 2022; 118:103692. [PMID: 34883241 PMCID: PMC8928575 DOI: 10.1016/j.mcn.2021.103692] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 01/03/2023] Open
Abstract
Afferent innervation of the cochlea by the auditory nerve declines during aging and potentially after sound overexposure, producing the common pathology known as cochlear synaptopathy. Auditory-nerve-fiber loss is difficult to detect with the clinical audiogram and has been proposed to cause 'hidden hearing loss' including impaired speech-in-noise perception. While evidence that auditory-nerve-fiber loss causes hidden hearing loss in humans is controversial, behavioral animal models hold promise to rigorously test this hypothesis because neural lesions can be induced and histologically validated. Here, we review recent animal behavioral studies on the impact of auditory-nerve-fiber loss on perception in a range of species. We first consider studies of tinnitus and hyperacusis inferred from acoustic startle reflexes, followed by a review of operant-conditioning studies of the audiogram, temporal integration for tones of varying duration, temporal resolution of gaps in noise, and tone-in-noise detection. Studies quantifying the audiogram show that tone-in-quiet sensitivity is unaffected by auditory-nerve-fiber loss unless neural lesions exceed 80%, at which point large deficits are possible. Changes in other aspects of perception, which were typically investigated for moderate-to-severe auditory-nerve-fiber loss of 50-70%, appear heterogeneous across studies and might be small compared to impairment caused by hair-cell pathologies. Future studies should pursue recent findings that behavioral sensitivity to brief tones and silent gaps in noise may be particularly vulnerable to auditory-nerve-fiber loss. Furthermore, aspects of auditory perception linked to central inhibition and fine neural response timing, such as modulation masking release and spatial hearing, may be productive directions for further animal behavioral research.
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Affiliation(s)
- Kenneth S Henry
- Departments of Otolaryngology, Biomedical Engineering, and Neuroscience, University of Rochester, Rochester, NY, USA.
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Theodoroff SM, Gallun FJ, McMillan GP, Molis M, Srinivasan N, Gordon J, McDermott D, Konrad-Martin D. Impacts of Diabetes, Aging, and Hearing Loss on Speech-on-Speech Masking and Spatial Release in a Large Veteran Cohort. Am J Audiol 2021; 30:1023-1036. [PMID: 34633838 DOI: 10.1044/2021_aja-21-00022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Type 2 diabetes mellitus (DM2) is associated with impaired hearing. However, the evidence is less clear if DM2 can lead to difficulty understanding speech in complex acoustic environments, independently of age and hearing loss effects. The purpose of this study was to estimate the magnitude of DM2-related effects on speech understanding in the presence of competing speech after adjusting for age and hearing. METHOD A cross-sectional study design was used to investigate the relationship between DM2 and speech understanding in 190 Veterans (M age = 47 years, range: 25-76). Participants were classified as having no diabetes (n = 74), prediabetes (n = 19), or DM2 that was well controlled (n = 24) or poorly controlled (n = 73). A test of spatial release from masking (SRM) was presented in a virtual acoustical simulation over insert earphones with multiple talkers using sentences from the coordinate response measure corpus to determine the target-to-masker ratio (TMR) required for 50% correct identification of target speech. A linear mixed model of the TMR results was used to estimate SRM and separate effects of diabetes group, age, and low-frequency pure-tone average (PTA-low) and high-frequency pure-tone average. A separate model estimated the effects of DM2 on PTA-low. RESULTS After adjusting for hearing and age, diabetes-related effects remained among those whose DM2 was well controlled, showing an SRM loss of approximately 0.5 dB. Results also showed effects of hearing loss and age, consistent with the literature on people without DM2. Low-frequency hearing loss was greater among those with DM2. CONCLUSIONS In a large cohort of Veterans, low-frequency hearing loss and older age negatively impact speech understanding. Compared with nondiabetics, individuals with controlled DM2 have additional auditory deficits beyond those associated with hearing loss or aging. These results provide a potential explanation for why individuals who have diabetes and/or are older often report difficulty understanding speech in real-world listening environments. SUPPLEMENTAL MATERIAL https://doi.org/10.23641/asha.16746475.
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Affiliation(s)
- Sarah M. Theodoroff
- VA Rehabilitation Research and Development Service, National Center for Rehabilitative Auditory Research, VA Portland Health Care System, United States Department of Veterans Affairs, OR
- Department of Otolaryngology—Head & Neck Surgery, Oregon Health & Science University, Portland
| | - Frederick J. Gallun
- VA Rehabilitation Research and Development Service, National Center for Rehabilitative Auditory Research, VA Portland Health Care System, United States Department of Veterans Affairs, OR
- Department of Otolaryngology—Head & Neck Surgery, Oregon Health & Science University, Portland
| | - Garnett P. McMillan
- VA Rehabilitation Research and Development Service, National Center for Rehabilitative Auditory Research, VA Portland Health Care System, United States Department of Veterans Affairs, OR
| | - Michelle Molis
- VA Rehabilitation Research and Development Service, National Center for Rehabilitative Auditory Research, VA Portland Health Care System, United States Department of Veterans Affairs, OR
- Department of Otolaryngology—Head & Neck Surgery, Oregon Health & Science University, Portland
| | - Nirmal Srinivasan
- Department of Speech-Language Pathology & Audiology, Towson University, MD
| | - Jane Gordon
- VA Rehabilitation Research and Development Service, National Center for Rehabilitative Auditory Research, VA Portland Health Care System, United States Department of Veterans Affairs, OR
| | - Daniel McDermott
- VA Rehabilitation Research and Development Service, National Center for Rehabilitative Auditory Research, VA Portland Health Care System, United States Department of Veterans Affairs, OR
| | - Dawn Konrad-Martin
- VA Rehabilitation Research and Development Service, National Center for Rehabilitative Auditory Research, VA Portland Health Care System, United States Department of Veterans Affairs, OR
- Department of Otolaryngology—Head & Neck Surgery, Oregon Health & Science University, Portland
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12
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Current topics in hearing research: Deafferentation and threshold independent hearing loss. Hear Res 2021; 419:108408. [PMID: 34955321 DOI: 10.1016/j.heares.2021.108408] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 11/20/2022]
Abstract
Hearing research findings in recent years have begun to change how we think about hearing loss and how we consider the risk of auditory damage from noise exposure. These findings include evidence of noise-induced cochlear damage in the absence of corresponding permanent threshold elevation or evidence of hair cell loss. Animal studies in several species have shown that noise exposures that produce robust but only temporary threshold shifts can permanently damage inner hair cell synaptic ribbons. This type of synaptic degeneration has also been shown to occur as a result of aging in animals and humans. The emergence of these data has motivated a number of clinical studies aimed at identifying the perceptual correlates associated with synaptopathy. The deficits believed to arise from synaptopathy include poorer hearing in background noise, tinnitus and hyperacusis (loudness intolerance). However, the findings from human studies have been mixed. Key questions remain as to whether synaptopathy reliably produces suprathreshold perceptual deficits or whether it serves as an early indicator of auditory damage with suprathreshold deficits emerging later as a function of further cochlear damage. Here, we provide an overview of both human and animal studies that explore the relationship among inner hair cell damage, including loss of afferent synapses, auditory thresholds, and suprathreshold measures of hearing.
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Bramhall NF. Use of the auditory brainstem response for assessment of cochlear synaptopathy in humans. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 150:4440. [PMID: 34972291 PMCID: PMC10880747 DOI: 10.1121/10.0007484] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/07/2021] [Indexed: 06/14/2023]
Abstract
Although clinical use of the auditory brainstem response (ABR) to detect retrocochlear disorders has been largely replaced by imaging in recent years, the discovery of cochlear synaptopathy has thrown this foundational measure of auditory function back into the spotlight. Whereas modern imaging now allows for the noninvasive detection of vestibular schwannomas, imaging technology is not currently capable of detecting cochlear synaptopathy, the loss of the synaptic connections between the inner hair cells and afferent auditory nerve fibers. However, animal models indicate that the amplitude of the first wave of the ABR, a far-field evoked potential generated by the synchronous firing of auditory nerve fibers, is highly correlated with synaptic integrity. This has led to many studies investigating the use of the ABR as a metric of synaptopathy in humans. However, these studies have yielded mixed results, leading to a lack of consensus about the utility of the ABR as an indicator of synaptopathy. This review summarizes the animal and human studies that have investigated the ABR as a measure of cochlear synaptic function, discusses factors that may have contributed to the mixed findings and the lessons learned, and provides recommendations for future use of this metric in the research and clinical settings.
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Affiliation(s)
- Naomi F Bramhall
- Veterans Affairs (VA) Rehabilitation Research & Development Service (RR&D) National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System Portland, Oregon 97239, USA
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Lin X, Luo J, Tan J, Yang L, Wang M, Li P. Experimental animal models of drug-induced sensorineural hearing loss: a narrative review. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1393. [PMID: 34733945 PMCID: PMC8506545 DOI: 10.21037/atm-21-2508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 08/16/2021] [Indexed: 01/19/2023]
Abstract
Objective This narrative review describes experimental animal models of sensorineural hearing loss (SNHL) caused by ototoxic agents. Background SNHL primarily results from damage to the sensory organ within the inner ear or the vestibulocochlear nerve (cranial nerve VIII). The main etiology of SNHL includes genetic diseases, presbycusis, ototoxic agents, infection, and noise exposure. Animal models with functional and anatomic damage to the sensory organ within the inner ear or the vestibulocochlear nerve mimicking the damage seen in humans are employed to explore the mechanism and potential treatment of SNHL. These animal models of SNHL are commonly established using ototoxic agents. Methods A literature search of PubMed, Embase, and Web of Science was performed for research articles on hearing loss and ototoxic agents in animal models of hearing loss. Conclusions Common ototoxic medications such as aminoglycoside antibiotics (AABs) and platinum antitumor drugs are extensively used to induce SNHL in experimental animals. The effect of ototoxic agents in vivo is influenced by the chemical mechanisms of the ototoxic agents, the species of animal, routes of administration of the ototoxic agents, and the dosage of ototoxic agents. Animal models of drug-induced SNHL contribute to understanding the hearing mechanism and reveal the function of different parts of the auditory system in humans.
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Affiliation(s)
- Xuexin Lin
- Department of Otolaryngology Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jia Luo
- Department of Otolaryngology Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jingqian Tan
- Department of Otolaryngology Head and Neck Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Luoying Yang
- Department of Otolaryngology Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Mitian Wang
- Department of Otolaryngology Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-sen University Yuedong Hospital, Meizhou, China
| | - Peng Li
- Department of Otolaryngology Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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Hancock KE, O'Brien B, Santarelli R, Liberman MC, Maison SF. The summating potential in human electrocochleography: Gaussian models and Fourier analysis. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 150:2492. [PMID: 34717457 PMCID: PMC8637743 DOI: 10.1121/10.0006572] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 05/07/2023]
Abstract
In recent electrocochleographic studies, the amplitude of the summating potential (SP) was an important predictor of performance on word-recognition in difficult listening environments among normal-hearing listeners; paradoxically the SP was largest in those with the worst scores. SP has traditionally been extracted by visual inspection, a technique prone to subjectivity and error. Here, we assess the utility of a fitting algorithm [Kamerer, Neely, and Rasetshwane (2020). J Acoust Soc Am. 147, 25-31] using a summed-Gaussian model to objectify and improve SP identification. Results show that SPs extracted by visual inspection correlate better with word scores than those from the model fits. We also use fast Fourier transform to decompose these evoked responses into their spectral components to gain insight into the cellular generators of SP. We find a component at 310 Hz associated with word-identification tasks that correlates with SP amplitude. This component is absent in patients with genetic mutations affecting synaptic transmission and may reflect a contribution from excitatory post-synaptic potentials in auditory nerve fibers.
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Affiliation(s)
- Kenneth E Hancock
- Department of Otolaryngology - Head & Neck Surgery, Harvard Medical School and Eaton-Peabody Laboratories, Massachusetts Eye & Ear, 243 Charles Street, Boston, Massachusetts 02115, USA
| | - Bennett O'Brien
- Eaton-Peabody Laboratories, Massachusetts Eye & Ear, 243 Charles Street, Boston, Massachusetts 02115, USA
| | - Rosamaria Santarelli
- Department of Neurosciences, University of Padova, Via Giustiniani 2, 35128 Padova, Italy
| | - M Charles Liberman
- Department of Otolaryngology - Head & Neck Surgery, Harvard Medical School and Eaton-Peabody Laboratories, Massachusetts Eye & Ear, 243 Charles Street, Boston, Massachusetts 02115, USA
| | - Stéphane F Maison
- Department of Otolaryngology - Head & Neck Surgery, Harvard Medical School and Eaton-Peabody Laboratories, Massachusetts Eye & Ear, 243 Charles Street, Boston, Massachusetts 02115, USA
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16
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Jiang Z, Wang J, Feng Y, Sun D, Zhang X, Shi H, Wang J, Salvi R, Wang H, Yin S. Analysis of Early Biomarkers Associated With Noise-Induced Hearing Loss Among Shipyard Workers. JAMA Netw Open 2021; 4:e2124100. [PMID: 34477849 PMCID: PMC8417765 DOI: 10.1001/jamanetworkopen.2021.24100] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
IMPORTANCE It is important to determine what frequencies and auditory perceptual measures are the most sensitive early indicators of noise-induced hearing impairment. OBJECTIVES To examine whether hearing loss among shipyard workers increases more rapidly at extended high frequencies than at clinical frequencies and whether subtle auditory processing deficits are present in those with extensive noise exposure but little or no hearing loss. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study collected audiometric data (0.25-16 kHz), survey questionnaires, and noise exposure levels from 7890 shipyard workers in a Shanghai shipyard from 2015 to 2019. Worsening hearing loss was evaluated in the group with hearing loss. Speech processing and temporal processing were evaluated in 610 participants with noise exposure and clinically normal hearing to identify early biomarkers of noise-induced hearing impairment. Data analysis was conducted from November to December 2020. MAIN OUTCOMES AND MEASURES Linear regression was performed to model the increase in hearing loss as function of cumulative noise exposure and compared with a group who were monitored longitudinally for 4 years. Auditory processing tests included speech-in-noise tests, competing sentence tests, dichotic listening tests, and gap detection threshold tests and were compared with a control group without history of noise exposure. RESULTS Of the 5539 participants (median [interquartile range (IQR)] age, 41.0 [34.0-47.0] years; 3861 [86.6%] men) included in the cross-sectional analysis, 4459 (80.5%) were hearing loss positive and 1080 (19.5%) were hearing loss negative. In younger participants (ie, ≤40 years), the maximum rate of increase in hearing loss was 0.40 (95% CI, 0.39-0.42) dB per A-weighted dB-year (dB/dBA-year) at 12.5 kHz, higher than the growth rates of 0.36 (95% CI, 0.35-0.36) dB/dBA-year at 4 kHz, 0.32 (95% CI, 0.31-0.33) dB/dBA-year at 10 kHz, 0.31 (95% CI, 0.30-0.31) dB/dBA-year at 6 kHz, 0.27 (95% CI, 0.26-0.27) dB/dBA-year at 3 kHz, and 0.27 (95% CI, 0.27-0.28) dB/dBA-year at 8 kHz. In the 4-year longitudinal analysis of hearing loss among 403 participants, the mean (SD) annual deterioration in hearing was 2.70 (2.98) dB/y at 12.5 kHz, almost twice as that observed at lower frequencies (eg, at 3kHz: 1.18 [2.15] dB/y). The auditory processing scores of participants with clinically normal hearing and a history of noise exposure were significantly lower than those of control participants (eg, median [IQR] score on speech-in-noise test, noise-exposed group 1 vs control group: 0.63 [0.55-0.66] vs 0.78 [0.76-0.80]; P < .001). CONCLUSIONS AND RELEVANCE These findings suggest that the increase in hearing loss among shipyard workers was more rapid at 12.5 kHz than at other frequencies; workers with clinically normal hearing but high cumulative noise exposure are likely to exhibit deficits in speech and temporal processing.
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Affiliation(s)
- Zhuang Jiang
- Department of Otolaryngology–Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Jiping Wang
- Department of Otolaryngology–Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Yanmei Feng
- Department of Otolaryngology–Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Daoyuan Sun
- Department of Occupational Disease, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xunmiao Zhang
- Department of Occupational Disease, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Haibo Shi
- Department of Otolaryngology–Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Jian Wang
- School of Communication Science and Disorders, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, New York
| | - Hui Wang
- Department of Otolaryngology–Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Shankai Yin
- Department of Otolaryngology–Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
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