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He S, Skidmore J, Bruce IC, Oleson JJ, Yuan Y. Peripheral Neural Synchrony in Postlingually Deafened Adult Cochlear Implant Users. Ear Hear 2024; 45:1125-1137. [PMID: 38503720 PMCID: PMC11333193 DOI: 10.1097/aud.0000000000001502] [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: 03/21/2024]
Abstract
OBJECTIVES This paper reports a noninvasive method for quantifying neural synchrony in the cochlear nerve (i.e., peripheral neural synchrony) in cochlear implant (CI) users, which allows for evaluating this physiological phenomenon in human CI users for the first time in the literature. In addition, this study assessed how peripheral neural synchrony was correlated with temporal resolution acuity and speech perception outcomes measured in quiet and in noise in postlingually deafened adult CI users. It tested the hypothesis that peripheral neural synchrony was an important factor for temporal resolution acuity and speech perception outcomes in noise in postlingually deafened adult CI users. DESIGN Study participants included 24 postlingually deafened adult CI users with a Cochlear™ Nucleus® device. Three study participants were implanted bilaterally, and each ear was tested separately. For each of the 27 implanted ears tested in this study, 400 sweeps of the electrically evoked compound action potential (eCAP) were measured at four electrode locations across the electrode array. Peripheral neural synchrony was quantified at each electrode location using the phase-locking value (PLV), which is a measure of trial-by-trial phase coherence among eCAP sweeps/trials. Temporal resolution acuity was evaluated by measuring the within-channel gap detection threshold (GDT) using a three-alternative, forced-choice procedure in a subgroup of 20 participants (23 implanted ears). For each ear tested in these participants, GDTs were measured at two electrode locations with a large difference in PLVs. For 26 implanted ears tested in 23 participants, speech perception performance was evaluated using consonant-nucleus-consonant (CNC) word lists presented in quiet and in noise at signal to noise ratios (SNRs) of +10 and +5 dB. Linear Mixed effect Models were used to evaluate the effect of electrode location on the PLV and the effect of the PLV on GDT after controlling for the stimulation level effects. Pearson product-moment correlation tests were used to assess the correlations between PLVs, CNC word scores measured in different conditions, and the degree of noise effect on CNC word scores. RESULTS There was a significant effect of electrode location on the PLV after controlling for the effect of stimulation level. There was a significant effect of the PLV on GDT after controlling for the effects of stimulation level, where higher PLVs (greater synchrony) led to lower GDTs (better temporal resolution acuity). PLVs were not significantly correlated with CNC word scores measured in any listening condition or the effect of competing background noise presented at an SNR of +10 dB on CNC word scores. In contrast, there was a significant negative correlation between the PLV and the degree of noise effect on CNC word scores for a competing background noise presented at an SNR of +5 dB, where higher PLVs (greater synchrony) correlated with smaller noise effects on CNC word scores. CONCLUSIONS This newly developed method can be used to assess peripheral neural synchrony in CI users, a physiological phenomenon that has not been systematically evaluated in electrical hearing. Poorer peripheral neural synchrony leads to lower temporal resolution acuity and is correlated with a larger detrimental effect of competing background noise presented at an SNR of 5 dB on speech perception performance in postlingually deafened adult CI users.
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Affiliation(s)
- Shuman He
- Department of Otolaryngology – Head and Neck Surgery, The Ohio State University, 915 Olentangy River Road, Columbus, OH 43212
- Department of Audiology, Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, OH 43205
| | - Jeffrey Skidmore
- Department of Otolaryngology – Head and Neck Surgery, The Ohio State University, 915 Olentangy River Road, Columbus, OH 43212
| | - Ian C. Bruce
- Department of Electrical & Computer Engineering, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Jacob J. Oleson
- Department of Biostatistics, The University of Iowa, Iowa City, IA 52242
| | - Yi Yuan
- Department of Otolaryngology – Head and Neck Surgery, The Ohio State University, 915 Olentangy River Road, Columbus, OH 43212
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Fujihira H, Yamagishi S, Furukawa S, Kashino M. Auditory brainstem response to paired clicks as a candidate marker of cochlear synaptopathy in humans. Clin Neurophysiol 2024; 165:44-54. [PMID: 38959535 DOI: 10.1016/j.clinph.2024.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 06/02/2024] [Accepted: 06/08/2024] [Indexed: 07/05/2024]
Abstract
OBJECTIVE This study aimed to evaluate whether auditory brainstem response (ABR) using a paired-click stimulation paradigm could serve as a tool for detecting cochlear synaptopathy (CS). METHODS The ABRs to single-clicks and paired-clicks with various inter-click intervals (ICIs) and scores for word intelligibility in degraded listening conditions were obtained from 57 adults with normal hearing. The wave I peak amplitude and root mean square values for the post-wave I response within a range delayed from the wave I peak (referred to as the RMSpost-w1) were calculated for the single- and second-click responses. RESULTS The wave I peak amplitudes did not correlate with age except for the second-click responses at an ICI of 7 ms, and the word intelligibility scores. However, we found that the RMSpost-w1 values for the second-click responses significantly decreased with increasing age. Moreover, the RMSpost-w1 values for the second-click responses at an ICI of 5 ms correlated significantly with the scores for word intelligibility in degraded listening conditions. CONCLUSIONS The magnitude of the post-wave I response for the second-click response could serve as a tool for detecting CS in humans. SIGNIFICANCE Our findings shed new light on the analytical methods of ABR for quantifying CS.
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Affiliation(s)
- Haruna Fujihira
- NTT Communication Science Laboratories, Atsugi, Kanagawa, Japan; Department of Informatics, Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan.
| | | | - Shigeto Furukawa
- NTT Communication Science Laboratories, Atsugi, Kanagawa, Japan; Graduate School of Public Health, Shizuoka Graduate University of Public Health, Shizuoka, Japan; Speech-Language-Hearing Center, Shizuoka General Hospital, Shizuoka, Japan
| | - Makio Kashino
- NTT Communication Science Laboratories, Atsugi, Kanagawa, Japan
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Sammeth CA, Walker KA, Greene NT, Klug A, Tollin DJ. Degradation in Binaural and Spatial Hearing and Auditory Temporal Processing Abilities as a Function of Aging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.08.602575. [PMID: 39026701 PMCID: PMC11257585 DOI: 10.1101/2024.07.08.602575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Objective Sensorineural hearing loss is common with advancing age, but even with normal or near normal hearing in older persons, performance deficits are often seen for suprathreshold listening tasks such as understanding speech in background noise or localizing sound direction. This suggests there is also a more central source of the problem. Objectives of this study were to examine as a function of age (young adult to septuagenarian) performance on: 1) a spatial acuity task examining lateralization ability, and a spatial speech-in-noise (SSIN) recognition task, both measured in a hemi-anechoic sound field using a circular horizontal-plane loudspeaker array, and 2) a suprathreshold auditory temporal processing task and a spectro-temporal processing task, both measured under headphones. Further, we examined any correlations between the measures.DesignSubjects were 48 adults, aged 21 to 78, with either normal hearing or only a mild sensorineural hearing loss through 4000 Hz. The lateralization task measured minimum audible angle (MAA) for 500 and 4000 Hz narrowband noise (NBN) bursts in diffuse background noise for both an on-axis (subject facing 0°) and off-axis (facing 45°) listening condition at signal-to-noise ratios (SNRs) of -3, -6, -9, and -12 dB. For 42 of the subjects, SSIN testing was also completed for key word recognition in sentences in multi-talker babble noise; specifically, the separation between speech and noise loudspeakers was adaptively varied to determine the difference needed for 40% and 80% correct performance levels. Finally, auditory temporal processing ability was examined using the Temporal Fine Structure test (44 subjects), and the Spectro-Temporal Modulation test (46 subjects). Results Mean lateralization performances were poorer (larger MAAs) in older compared to younger subjects, particularly in the more adverse listening conditions (4000 Hz, off-axis, and poorer SNRs). Performance variability was notably higher for older subjects than for young adults. The 4000 Hz NBN bursts produced larger MAAs than did 500 Hz NBN bursts. The SSIN data also showed declining mean performance with age at both criterion levels, with greater variability again found for older subjects. Spearman rho analyses revealed some low to moderate, but significant correlation coefficients for age versus MAA and age versus SSIN results. A low but significant correlation was also observed between the most adverse MAA and SSIN conditions. Results from both the TFS and STM assessments showed decreased mean performance with aging, and revealed moderate, significant correlations, with the strongest relationship shown with the TFS test. Finally, of note, extended-high-frequency (EHF) hearing loss (measured between 9000 and 16,000 Hz) was found in older but not young subjects, and correlated with decreasing performance on several tasks. Conclusions Particularly for more adverse listening conditions, age-related deficits were found on both of the spatial hearing tasks and in temporal and spectro-temporal processing abilities. It may be that deficits in temporal processing ability contribute to poorer spatial hearing performance in older subjects due to inaccurate coding of binaural/interaural timing information sent from the periphery to the brainstem. In addition, EHF hearing loss may be a coexisting factor in the reduced performance in older subjects.
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Steenken F, Pektaş A, Köppl C. Age-related changes in olivocochlear efferent innervation in gerbils. Front Synaptic Neurosci 2024; 16:1422330. [PMID: 38887655 PMCID: PMC11180762 DOI: 10.3389/fnsyn.2024.1422330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 05/20/2024] [Indexed: 06/20/2024] Open
Abstract
Introduction Age-related hearing difficulties have a complex etiology that includes degenerative processes in the sensory cochlea. The cochlea comprises the start of the afferent, ascending auditory pathway, but also receives efferent feedback innervation by two separate populations of brainstem neurons: the medial olivocochlear and lateral olivocochlear pathways, innervating the outer hair cells and auditory-nerve fibers synapsing on inner hair cells, respectively. Efferents are believed to improve hearing under difficult conditions, such as high background noise. Here, we compare olivocochlear efferent innervation density along the tonotopic axis in young-adult and aged gerbils (at ~50% of their maximum lifespan potential), a classic animal model for age-related hearing loss. Methods Efferent synaptic terminals and sensory hair cells were labeled immunohistochemically with anti-synaptotagmin and anti-myosin VIIa, respectively. Numbers of hair cells, numbers of efferent terminals, and the efferent innervation area were quantified at seven tonotopic locations along the organ of Corti. Results The tonotopic distribution of olivocochlear innervation in the gerbil was similar to that previously shown for other species, with a slight apical cochlear bias in presumed lateral olivocochlear innervation (inner-hair-cell region), and a broad mid-cochlear peak for presumed medial olivocochlear innervation (outer-hair-cell region). We found significant, age-related declines in overall efferent innervation to both the inner-hair-cell and the outer-hair-cell region. However, when accounting for the age-related losses in efferent target structures, the innervation density of surviving elements proved unchanged in the inner-hair-cell region. For outer hair cells, a pronounced increase of orphaned outer hair cells, i.e., lacking efferent innervation, was observed. Surviving outer hair cells that were still efferently innervated retained a nearly normal innervation. Discussion A comparison across species suggests a basic aging scenario where outer hair cells, type-I afferents, and the efferents associated with them, steadily die away with advancing age, but leave the surviving cochlear circuitry largely intact until an advanced age, beyond 50% of a species' maximum lifespan potential. In the outer-hair-cell region, MOC degeneration may precede outer-hair-cell death, leaving a putatively transient population of orphaned outer hair cells that are no longer under efferent control.
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Affiliation(s)
- Friederike Steenken
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
- Cluster of Excellence “Hearing4all”, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Asli Pektaş
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Christine Köppl
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
- Cluster of Excellence “Hearing4all”, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
- Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
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Dias JW, McClaskey CM, Alvey AP, Lawson A, Matthews LJ, Dubno JR, Harris KC. Effects of age and noise exposure history on auditory nerve response amplitudes: A systematic review, study, and meta-analysis. Hear Res 2024; 447:109010. [PMID: 38744019 PMCID: PMC11135078 DOI: 10.1016/j.heares.2024.109010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/08/2024] [Accepted: 04/18/2024] [Indexed: 05/16/2024]
Abstract
Auditory nerve (AN) function has been hypothesized to deteriorate with age and noise exposure. Here, we perform a systematic review of published studies and find that the evidence for age-related deficits in AN function is largely consistent across the literature, but there are inconsistent findings among studies of noise exposure history. Further, evidence from animal studies suggests that the greatest deficits in AN response amplitudes are found in noise-exposed aged mice, but a test of the interaction between effects of age and noise exposure on AN function has not been conducted in humans. We report a study of our own examining differences in the response amplitude of the compound action potential N1 (CAP N1) between younger and older adults with and without a self-reported history of noise exposure in a large sample of human participants (63 younger adults 18-30 years of age, 103 older adults 50-86 years of age). CAP N1 response amplitudes were smaller in older than younger adults. Noise exposure history did not appear to predict CAP N1 response amplitudes, nor did the effect of noise exposure history interact with age. We then incorporated our results into two meta-analyses of published studies of age and noise exposure history effects on AN response amplitudes in neurotypical human samples. The meta-analyses found that age effects across studies are robust (r = -0.407), but noise exposure effects are weak (r = -0.152). We conclude that noise exposure effects may be highly variable depending on sample characteristics, study design, and statistical approach, and researchers should be cautious when interpreting results. The underlying pathology of age-related and noise-induced changes in AN function are difficult to determine in living humans, creating a need for longitudinal studies of changes in AN function across the lifespan and histological examination of the AN from temporal bones collected post-mortem.
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Affiliation(s)
- James W Dias
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States.
| | - Carolyn M McClaskey
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - April P Alvey
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - Abigail Lawson
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - Lois J Matthews
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - Judy R Dubno
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - Kelly C Harris
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
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Bartholomew RA, Hoffman SE, Juliano AF, Wu PZ, Zhao Y, de Gruttola V, Liberman MC, Maison SF. On the Difficulty Predicting Word Recognition Performance After Cochlear Implantation. Otol Neurotol 2024; 45:e393-e399. [PMID: 38573598 PMCID: PMC11087198 DOI: 10.1097/mao.0000000000004176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
HYPOTHESIS Preimplantation word scores cannot reliably predict postimplantation outcomes. BACKGROUND To date, there is no model based on preoperative data that can reliably predict the postoperative outcomes of cochlear implantation in the postlingually deafened adult patient. METHODS In a group of 228 patients who received a cochlear implant between 2002 and 2021, we tested the predictive power of nine variables (age, etiology, sex, laterality of implantation, preimplantation thresholds and word scores, as well as the design, insertion approach, and angular insertion depth of the electrode array) on postimplantation outcomes. Results of multivariable linear regression analyses were then interpreted in light of data obtained from histopathological analyses of human temporal bones. RESULTS Age and etiology were the only significant predictors of postimplantation outcomes. In agreement with many investigations, preimplantation word scores failed to significantly predict postimplantation outcomes. Analysis of temporal bone histopathology suggests that neuronal survival must fall below 40% before word scores in quiet begin to drop. Scores fall steeply with further neurodegeneration, such that only 20% survival can support acoustically driven word scores of 50%. Because almost all cochlear implant implantees have at least 20% of their spiral ganglion neurons (SGNs) surviving, it is expected that most cochlear implant users on average should improve to at least 50% word recognition score, as we observed, even if their preimplantation score was near zero as a result of widespread hair cell damage and the fact that ~50% of their SGNs have likely lost their peripheral axons. These "disconnected" SGNs would not contribute to acoustic hearing but likely remain electrically excitable. CONCLUSION The relationship between preimplantation word scores and data describing the survival of SGNs in humans can explain why preimplantation word scores obtained in unaided conditions fail to predict postimplantation outcomes.
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Affiliation(s)
| | | | - Amy F Juliano
- Department of Radiology, Massachusetts Eye & Ear, Harvard Medical School
| | | | - Yan Zhao
- Eaton-Peabody Laboratories, Massachusetts Eye & Ear
| | - Victor de Gruttola
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
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Sriperumbudur KK, Appali R, Gummer AW, van Rienen U. Understanding the impact of modiolus porosity on stimulation of spiral ganglion neurons by cochlear implants. Sci Rep 2024; 14:9593. [PMID: 38671022 PMCID: PMC11053021 DOI: 10.1038/s41598-024-59347-2] [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: 09/29/2023] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Moderate-to-profound sensorineural hearing loss in humans is treatable by electrically stimulating the auditory nerve (AN) with a cochlear implant (CI). In the cochlea, the modiolus presents a porous bony interface between the CI electrode and the AN. New bone growth caused by the presence of the CI electrode or neural degeneration inflicted by ageing or otological diseases might change the effective porosity of the modiolus and, thereby, alter its electrical material properties. Using a volume conductor description of the cochlea, with the aid of a 'mapped conductivity' method and an ad-hoc 'regionally kinetic' equation system, we show that even a slight variation in modiolus porosity or pore distribution can disproportionately affect AN stimulation. Hence, because of porosity changes, an inconsistent CI performance might occur if neural degeneration or new bone growth progress after implantation. Appropriate electrical material properties in accordance with modiolar morphology and pathology should be considered in patient-specific studies. The present first-of-its-kind in-silico study advocates for contextual experimental studies to further explore the utility of modiolus porous morphology in optimising the CI outcome.
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Affiliation(s)
- Kiran K Sriperumbudur
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany.
- Research and Development, MED-EL Medical Electronics GmbH, Innsbruck, Austria.
| | - Revathi Appali
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
| | - Anthony W Gummer
- Department of Otolaryngology, University of Tübingen, Tübingen, Germany.
- Department of Otolaryngology, University of Melbourne, Melbourne, Australia.
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
- Life, Light and Matter, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
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Hemachandran S, Hu N, Kane CJ, Green SH. Cyclic AMP signaling promotes regeneration of cochlear synapses after excitotoxic or noise trauma. Front Cell Neurosci 2024; 18:1363219. [PMID: 38694536 PMCID: PMC11061447 DOI: 10.3389/fncel.2024.1363219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 03/27/2024] [Indexed: 05/04/2024] Open
Abstract
Introduction Cochlear afferent synapses connecting inner hair cells to spiral ganglion neurons are susceptible to excitotoxic trauma on exposure to loud sound, resulting in a noise-induced cochlear synaptopathy (NICS). Here we assessed the ability of cyclic AMP-dependent protein kinase (PKA) signaling to promote cochlear synapse regeneration, inferred from its ability to promote axon regeneration in axotomized CNS neurons, another system refractory to regeneration. Methods We mimicked NICS in vitro by applying a glutamate receptor agonist, kainic acid (KA) to organotypic cochlear explant cultures and experimentally manipulated cAMP signaling to determine whether PKA could promote synapse regeneration. We then delivered the cAMP phosphodiesterase inhibitor rolipram via implanted subcutaneous minipumps in noise-exposed CBA/CaJ mice to test the hypothesis that cAMP signaling could promote cochlear synapse regeneration in vivo. Results We showed that the application of the cell membrane-permeable cAMP agonist 8-cpt-cAMP or the cAMP phosphodiesterase inhibitor rolipram promotes significant regeneration of synapses in vitro within twelve hours after their destruction by KA. This is independent of neurotrophin-3, which also promotes synapse regeneration. Moreover, of the two independent signaling effectors activated by cAMP - the cAMP Exchange Protein Activated by cAMP and the cAMP-dependent protein kinase - it is the latter that mediates synapse regeneration. Finally, we showed that systemic delivery of rolipram promotes synapse regeneration in vivo following NICS. Discussion In vitro experiments show that cAMP signaling promotes synapse regeneration after excitotoxic destruction of cochlear synapses and does so via PKA signaling. The cAMP phosphodiesterase inhibitor rolipram promotes synapse regeneration in vivo in noise-exposed mice. Systemic administration of rolipram or similar compounds appears to provide a minimally invasive therapeutic approach to reversing synaptopathy post-noise.
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Affiliation(s)
| | | | | | - Steven H. Green
- Department of Biology, University of Iowa, Iowa City, IA, United States
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Dias JW, McClaskey CM, Alvey AP, Lawson A, Matthews LJ, Dubno JR, Harris KC. Effects of Age and Noise Exposure History on Auditory Nerve Response Amplitudes: A Systematic Review, Study, and Meta-Analysis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.585882. [PMID: 38585917 PMCID: PMC10996537 DOI: 10.1101/2024.03.20.585882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Auditory nerve (AN) function has been hypothesized to deteriorate with age and noise exposure. Here, we perform a systematic review of published studies and find that the evidence for age-related deficits in AN function is largely consistent across the literature, but there are inconsistent findings among studies of noise exposure history. Further, evidence from animal studies suggests that the greatest deficits in AN response amplitudes are found in noise-exposed aged mice, but a test of the interaction between effects of age and noise exposure on AN function has not been conducted in humans. We report a study of our own examining differences in the response amplitude of the compound action potential N1 (CAP N1) between younger and older adults with and without a self-reported history of noise exposure in a large sample of human participants (63 younger adults 18-30 years of age, 103 older adults 50-86 years of age). CAP N1 response amplitudes were smaller in older than younger adults. Noise exposure history did not appear to predict CAP N1 response amplitudes, nor did the effect of noise exposure history interact with age. We then incorporated our results into two meta-analyses of published studies of age and noise exposure history effects on AN response amplitudes in neurotypical human samples. The meta-analyses found that age effects across studies are robust (r=-0.407), but noise-exposure effects are weak (r=-0.152). We conclude that noise-exposure effects may be highly variable depending on sample characteristics, study design, and statistical approach, and researchers should be cautious when interpreting results. The underlying pathology of age-related and noise-induced changes in AN function are difficult to determine in living humans, creating a need for longitudinal studies of changes in AN function across the lifespan and histological examination of the AN from temporal bones collected post-mortem.
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Affiliation(s)
- James W Dias
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Carolyn M McClaskey
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - April P Alvey
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Abigail Lawson
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Lois J Matthews
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Judy R Dubno
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Kelly C Harris
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
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10
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He S, Skidmore J, Bruce IC, Oleson JJ, Yuan Y. Peripheral neural synchrony in post-lingually deafened adult cochlear implant users. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2023.07.07.23292369. [PMID: 37461681 PMCID: PMC10350140 DOI: 10.1101/2023.07.07.23292369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Objective This paper reports a noninvasive method for quantifying neural synchrony in the cochlear nerve (i.e., peripheral neural synchrony) in cochlear implant (CI) users, which allows for evaluating this physiological phenomenon in human CI users for the first time in the literature. In addition, this study assessed how peripheral neural synchrony was correlated with temporal resolution acuity and speech perception outcomes measured in quiet and in noise in post-lingually deafened adult CI users. It tested the hypothesis that peripheral neural synchrony was an important factor for temporal resolution acuity and speech perception outcomes in noise in post-lingually deafened adult CI users. Design Study participants included 24 post-lingually deafened adult CI users with a Cochlear™ Nucleus® device. Three study participants were implanted bilaterally, and each ear was tested separately. For each of the 27 implanted ears tested in this study, 400 sweeps of the electrically evoked compound action potential (eCAP) were measured at four electrode locations across the electrode array. Peripheral neural synchrony was quantified at each electrode location using the phase locking value (PLV), which is a measure of trial-by-trial phase coherence among eCAP sweeps/trials. Temporal resolution acuity was evaluated by measuring the within-channel gap detection threshold (GDT) using a three-alternative, forced-choice procedure in a subgroup of 20 participants (23 implanted ears). For each ear tested in these participants, GDTs were measured at two electrode locations with a large difference in PLVs. For 26 implanted ears tested in 23 participants, speech perception performance was evaluated using Consonant-Nucleus-Consonant (CNC) word lists presented in quiet and in noise at signal-to-noise ratios (SNRs) of +10 and +5 dB. Linear Mixed effect Models were used to evaluate the effect of electrode location on the PLV and the effect of the PLV on GDT after controlling for the stimulation level effects. Pearson product-moment correlation tests were used to assess the correlations between PLVs, CNC word scores measured in different conditions, and the degree of noise effect on CNC word scores. Results There was a significant effect of electrode location on the PLV after controlling for the effect of stimulation level. There was a significant effect of the PLV on GDT after controlling for the effects of stimulation level, where higher PLVs (greater synchrony) led to lower GDTs (better temporal resolution acuity). PLVs were not significantly correlated with CNC word scores measured in any listening condition or the effect of competing background noise presented at a SNR of +10 dB on CNC word scores. In contrast, there was a significant negative correlation between the PLV and the degree of noise effect on CNC word scores for a competing background noise presented at a SNR of +5 dB, where higher PLVs (greater synchrony) correlated with smaller noise effects on CNC word scores. Conclusions This newly developed method can be used to assess peripheral neural synchrony in CI users, a physiological phenomenon that has not been systematically evaluated in electrical hearing. Poorer peripheral neural synchrony leads to lower temporal resolution acuity and is correlated with a larger detrimental effect of competing background noise presented at a SNR of 5 dB on speech perception performance in post-lingually deafened adult CI users.
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Affiliation(s)
- Shuman He
- Department of Otolaryngology – Head and Neck Surgery, The Ohio State University, 915 Olentangy River Road, Columbus, OH 43212
- Department of Audiology, Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, OH 43205
| | - Jeffrey Skidmore
- Department of Otolaryngology – Head and Neck Surgery, The Ohio State University, 915 Olentangy River Road, Columbus, OH 43212
| | - Ian C. Bruce
- Department of Electrical & Computer Engineering, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Jacob J. Oleson
- Department of Biostatistics, The University of Iowa, Iowa City, IA 52242
| | - Yi Yuan
- Department of Otolaryngology – Head and Neck Surgery, The Ohio State University, 915 Olentangy River Road, Columbus, OH 43212
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11
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Charlton PE, Burke K, Kobrina A, Lauer AM, Dent ML. The perception of ultrasonic vocalizations by laboratory mice following intense noise exposures. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:867-878. [PMID: 38310604 PMCID: PMC10838193 DOI: 10.1121/10.0024614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 01/02/2024] [Accepted: 01/11/2024] [Indexed: 02/06/2024]
Abstract
Noise-induced hearing loss interacts with age, sex, and listening conditions to affect individuals' perception of ecologically relevant stimuli like speech. The present experiments assessed the impact of age and sex on vocalization detection by noise-exposed mice trained to detect a downsweep or complex ultrasonic vocalization in quiet or in the presence of a noise background. Daily thresholds before and following intense noise exposure were collected longitudinally and compared across several factors. All mice, regardless of age, sex, listening condition, or stimulus type showed their poorest behavioral sensitivity immediately after the noise exposure. There were varying degrees of recovery over time and across factors. Old-aged mice had greater threshold shifts and less recovery compared to middle-aged mice. Mice had larger threshold shifts and less recovery for downsweeps than for complex vocalizations. Female mice were more sensitive, had smaller post-noise shifts, and had better recovery than males. Thresholds in noise were higher and less variable than thresholds in quiet, but there were comparable shifts and recovery. In mice, as in humans, the perception of ecologically relevant stimuli suffers after an intense noise exposure, and results differ from simple tone detection findings.
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Affiliation(s)
- Payton E Charlton
- Department of Psychology, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| | - Kali Burke
- Department of Psychology, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| | - Anastasiya Kobrina
- Department of Psychology, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| | - Amanda M Lauer
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, Maryland 21287, USA
| | - Micheal L Dent
- Department of Psychology, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
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12
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Xie R, Wang M, Zhang C. Mechanisms of age-related hearing loss at the auditory nerve central synapses and postsynaptic neurons in the cochlear nucleus. Hear Res 2024; 442:108935. [PMID: 38113793 PMCID: PMC10842789 DOI: 10.1016/j.heares.2023.108935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/04/2023] [Accepted: 12/08/2023] [Indexed: 12/21/2023]
Abstract
Sound information is transduced from mechanical vibration to electrical signals in the cochlea, conveyed to and further processed in the brain to form auditory perception. During the process, spiral ganglion neurons (SGNs) are the key cells that connect the peripheral and central auditory systems by receiving information from hair cells in the cochlea and transmitting it to neurons of the cochlear nucleus (CN). Decades of research in the cochlea greatly improved our understanding of SGN function under normal and pathological conditions, especially about the roles of different subtypes of SGNs and their peripheral synapses. However, it remains less clear how SGN central terminals or auditory nerve (AN) synapses connect to CN neurons, and ultimately how peripheral pathology links to structural alterations and functional deficits in the central auditory nervous system. This review discusses recent progress about the morphological and physiological properties of different subtypes of AN synapses and associated postsynaptic CN neurons, their changes during aging, and the potential mechanisms underlying age-related hearing loss.
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Affiliation(s)
- Ruili Xie
- Department of Otolaryngology, The Ohio State University, 420 W 12th Ave, Columbus OH 43210, USA; Department of Neuroscience, The Ohio State University, 420W 12th Ave, Columbus, OH 43210, USA.
| | - Meijian Wang
- Department of Otolaryngology, The Ohio State University, 420 W 12th Ave, Columbus OH 43210, USA
| | - Chuangeng Zhang
- Department of Otolaryngology, The Ohio State University, 420 W 12th Ave, Columbus OH 43210, USA
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13
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Saidia AR, François F, Casas F, Mechaly I, Venteo S, Veechi JT, Ruel J, Puel JL, Wang J. Oxidative Stress Plays an Important Role in Glutamatergic Excitotoxicity-Induced Cochlear Synaptopathy: Implication for Therapeutic Molecules Screening. Antioxidants (Basel) 2024; 13:149. [PMID: 38397748 PMCID: PMC10886292 DOI: 10.3390/antiox13020149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/12/2024] [Accepted: 01/20/2024] [Indexed: 02/25/2024] Open
Abstract
The disruption of the synaptic connection between the sensory inner hair cells (IHCs) and the auditory nerve fiber terminals of the type I spiral ganglion neurons (SGN) has been observed early in several auditory pathologies (e.g., noise-induced or ototoxic drug-induced or age-related hearing loss). It has been suggested that glutamate excitotoxicity may be an inciting element in the degenerative cascade observed in these pathological cochlear conditions. Moreover, oxidative damage induced by free hydroxyl radicals and nitric oxide may dramatically enhance cochlear damage induced by glutamate excitotoxicity. To investigate the underlying molecular mechanisms involved in cochlear excitotoxicity, we examined the molecular basis responsible for kainic acid (KA, a full agonist of AMPA/KA-preferring glutamate receptors)-induced IHC synapse loss and degeneration of the terminals of the type I spiral ganglion afferent neurons using a cochlear explant culture from P3 mouse pups. Our results demonstrated that disruption of the synaptic connection between IHCs and SGNs induced increased levels of oxidative stress, as well as altered both mitochondrial function and neurotrophin signaling pathways. Additionally, the application of exogenous antioxidants and neurotrophins (NT3, BDNF, and small molecule TrkB agonists) clearly increases synaptogenesis. These results suggest that understanding the molecular pathways involved in cochlear excitotoxicity is of crucial importance for the future clinical trials of drug interventions for auditory synaptopathies.
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Affiliation(s)
- Anissa Rym Saidia
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Florence François
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - François Casas
- INRA, UMR 866 Dynamique Musculaire et Métabolisme, 34060 Montpellier, France;
| | - Ilana Mechaly
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Stéphanie Venteo
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Joseph T. Veechi
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Jérôme Ruel
- Centre de Recherche en CardioVasculaire et Nutrition, Aix-Marseille Université-INSERM, 1263-INRAE 1260, 13385 Marseille, France;
| | - Jean-Luc Puel
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Jing Wang
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
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14
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Henry KS, Guo AA, Abrams KS. Normal behavioral discrimination of envelope statistics in budgerigars with kainate-induced cochlear synaptopathy. Hear Res 2024; 441:108927. [PMID: 38096707 PMCID: PMC10775186 DOI: 10.1016/j.heares.2023.108927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/27/2023] [Accepted: 12/04/2023] [Indexed: 12/27/2023]
Abstract
Cochlear synaptopathy is a common pathology in humans associated with aging and potentially sound overexposure. Synaptopathy is widely expected to cause "hidden hearing loss," including difficulty perceiving speech in noise, but support for this hypothesis is controversial. Here in budgerigars (Melopsittacus undulatus), we evaluated the impact of long-term cochlear synaptopathy on behavioral discrimination of Gaussian noise (GN) and low-noise noise (LNN) signals processed to have a flatter envelope. Stimuli had center frequencies of 1-3kHz, 100-Hz bandwidth, and were presented at sensation levels (SLs) from 10 to 30dB. We reasoned that narrowband, low-SL stimuli of this type should minimize spread of excitation across auditory-nerve fibers, and hence might reveal synaptopathy-related defects if they exist. Cochlear synaptopathy was induced without hair-cell injury using kainic acid (KA). Behavioral threshold tracking experiments characterized the minimum stimulus duration above which animals could reliably discriminate between LNN and GN. Budgerigar thresholds for LNN-GN discrimination ranged from 40 to 60ms at 30dB SL, were similar across frequencies, and increased for lower SLs. Notably, animals with long-term 39-77% estimated synaptopathy performed similarly to controls, requiring on average a ∼7.5% shorter stimulus duration (-0.7±1.0dB; mean difference ±SE) for LNN-GN discrimination. Decision-variable correlation analyses of detailed behavioral response patterns showed that individual animals relied on envelope cues to discriminate LNN and GN, with lesser roles of FM and energy cues; no difference was found between KA-exposed and control groups. These results suggest that long-term cochlear synaptopathy does not impair discrimination of low-level signals with different envelope statistics.
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Affiliation(s)
- Kenneth S Henry
- Department of Otolaryngology, University of Rochester, NY 14642, USA; Department of Biomedical Engineering, University of Rochester, Rochester, NY 14642, USA; Department of Neuroscience, University of Rochester, Rochester, NY 14642, USA.
| | - Anna A Guo
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14642, USA
| | - Kristina S Abrams
- Department of Neuroscience, University of Rochester, Rochester, NY 14642, USA
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15
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Han JH, Kim JH, Park GK, Lee HJ. Preserved Gray Matter Volume in the Left Superior Temporal Gyrus Underpins Speech-in-Noise Processing in Middle-Aged Adults. J Int Adv Otol 2024; 20:62-68. [PMID: 38454291 PMCID: PMC10895841 DOI: 10.5152/iao.2024.231241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/05/2023] [Indexed: 03/09/2024] Open
Abstract
BACKGROUND Neuroanatomical evidence suggests that behavioral speech-in-noise (SiN) perception and the underlying cortical structural network are altered by aging, and these aging-induced changes could be initiated during middle age. However, the mechanism behind the relationship between auditory performance and neural substrates of speech perception in middle-aged individuals remains unclear. In this study, we measured the structural volumes of selected neuroanatomical regions involved in speech and hearing processing to establish their association with speech perception ability in middle-aged adults. METHODS Sentence perception in quiet and noisy conditions was behaviorally measured in 2 different age groups: young (20-39 years old) and middle-aged (40-59-year-old) adults. Anatomical magnetic resonance images were taken to assess the gray matter volume of specific parcellated brain areas associated with speech perception. The relationships between these and behavioral auditory performance with age were determined. RESULTS The middle-aged adults showed poorer speech perception in both quiet and noisy conditions than the young adults. Neuroanatomical data revealed that the normalized gray matter volume in the left superior temporal gyrus, which is closely related to acoustic and phonological processing, is associated with behavioral SiN perception in the middle-aged group. In addition, the normalized gray matter volumes in multiple cortical areas seem to decrease with age. CONCLUSION The results indicate that SiN perception in middle-aged adults is closely related to the brain region responsible for lower-level speech processing, which involves the detection and phonemic representation of speech. Nonetheless, the higher-order cortex may also contribute to age-induced changes in auditory performance.
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Affiliation(s)
- Ji-Hye Han
- Laboratory of Brain and Cognitive Sciences for Convergence Medicine, Hallym University, College of Medicine, Anyang, Republic of Korea
- Ear and Interaction Center, Doheun Institute for Digital Innovation in Medicine (D.I.D.I.M.), Hallym University Medical Center, Anyang, South Korea
| | - Ja-Hee Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Hallym University, College of Medicine, Chuncheon, Republic of Korea
| | - Gin-Kyeong Park
- Laboratory of Brain and Cognitive Sciences for Convergence Medicine, Hallym University, College of Medicine, Anyang, Republic of Korea
| | - Hyo-Jeong Lee
- Laboratory of Brain and Cognitive Sciences for Convergence Medicine, Hallym University, College of Medicine, Anyang, Republic of Korea
- Ear and Interaction Center, Doheun Institute for Digital Innovation in Medicine (D.I.D.I.M.), Hallym University Medical Center, Anyang, South Korea
- Department of Otorhinolaryngology-Head and Neck Surgery, Hallym University, College of Medicine, Chuncheon, Republic of Korea
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16
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Liu J, Stohl J, Lopez-Poveda EA, Overath T. Quantifying the Impact of Auditory Deafferentation on Speech Perception. Trends Hear 2024; 28:23312165241227818. [PMID: 38291713 PMCID: PMC10832414 DOI: 10.1177/23312165241227818] [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: 06/05/2023] [Revised: 12/22/2023] [Accepted: 01/05/2024] [Indexed: 02/01/2024] Open
Abstract
The past decade has seen a wealth of research dedicated to determining which and how morphological changes in the auditory periphery contribute to people experiencing hearing difficulties in noise despite having clinically normal audiometric thresholds in quiet. Evidence from animal studies suggests that cochlear synaptopathy in the inner ear might lead to auditory nerve deafferentation, resulting in impoverished signal transmission to the brain. Here, we quantify the likely perceptual consequences of auditory deafferentation in humans via a physiologically inspired encoding-decoding model. The encoding stage simulates the processing of an acoustic input stimulus (e.g., speech) at the auditory periphery, while the decoding stage is trained to optimally regenerate the input stimulus from the simulated auditory nerve firing data. This allowed us to quantify the effect of different degrees of auditory deafferentation by measuring the extent to which the decoded signal supported the identification of speech in quiet and in noise. In a series of experiments, speech perception thresholds in quiet and in noise increased (worsened) significantly as a function of the degree of auditory deafferentation for modeled deafferentation greater than 90%. Importantly, this effect was significantly stronger in a noisy than in a quiet background. The encoding-decoding model thus captured the hallmark symptom of degraded speech perception in noise together with normal speech perception in quiet. As such, the model might function as a quantitative guide to evaluating the degree of auditory deafferentation in human listeners.
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Affiliation(s)
- Jiayue Liu
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - Joshua Stohl
- North American Research Laboratory, MED-EL Corporation, Durham, NC, USA
| | - Enrique A. Lopez-Poveda
- Instituto de Neurociencias de Castilla y Leon, University of Salamanca, Salamanca, Spain
- Departamento de Cirugía, Facultad de Medicina, University of Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Tobias Overath
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
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17
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Colla MDF, Lunardelo PP, Dias FAM. Cochlear synaptopathy and hidden hearing loss: a scoping review. Codas 2023; 36:e20230032. [PMID: 37991055 DOI: 10.1590/2317-1782/20232023032pt] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/10/2023] [Indexed: 11/23/2023] Open
Abstract
PURPOSE To identify the pathophysiological definitions adopted by studies investigating "cochlear synaptopathy" (CS) and "hidden hearing loss" (HHL). RESEARCH STRATEGIES The combination of keywords "Auditory Synaptopathy" or "Neuronal Synaptopathy" or "Hidden Hearing Loss" with "etiology" or "causality" or "diagnosis" was used in the databases EMBASE, Pubmed (MEDLINE), CINAHL (EBSCO), and Web of Science. SELECTION CRITERIA Studies that investigated CS or HHL in humans using behavioral and/or electrophysiological procedures were included. DATA ANALYSIS Data analysis and extraction were performed with regard to terminology, definitions, and population. RESULTS 49 articles were included. Of these, 61.2% used the CS terminology, 34.7% used both terms, and 4.1% used HHL. The most-studied conditions were exposure to noise and tinnitus. CONCLUSION CS terminology was used in most studies, referring to the pathophysiological process of deafferentiation between the cochlear nerve fibers and inner hair cells.
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Affiliation(s)
- Marina de Figueiredo Colla
- Departamento de Fonoaudiologia, Pontifícia Universidade Católica de Minas Gerais - PUC MG - Belo Horizonte (MG), Brasil
| | - Pamela Papile Lunardelo
- Programa de Pós-graduação em Psicobiologia, Universidade de São Paulo de Ribeirão Preto - USP RP - Ribeirão Preto (SP), Brasil
| | - Fernanda Abalen Martins Dias
- Departamento de Fonoaudiologia, Pontifícia Universidade Católica de Minas Gerais - PUC MG - Belo Horizonte (MG), Brasil
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18
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Bramhall NF, Theodoroff SM, McMillan GP, Kampel SD, Buran BN. Associations Between Physiological Correlates of Cochlear Synaptopathy and Tinnitus in a Veteran Population. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2023; 66:4635-4652. [PMID: 37889209 DOI: 10.1044/2023_jslhr-23-00234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
PURPOSE Animal models and human temporal bones indicate that noise exposure is a risk factor for cochlear synaptopathy, a possible etiology of tinnitus. Veterans are exposed to high levels of noise during military service. Therefore, synaptopathy may explain the high rates of noise-induced tinnitus among Veterans. Although synaptopathy cannot be directly evaluated in living humans, animal models indicate that several physiological measures are sensitive to synapse loss, including the auditory brainstem response (ABR), the middle ear muscle reflex (MEMR), and the envelope following response (EFR). The purpose of this study was to determine whether tinnitus is associated with reductions in physiological correlates of synaptopathy that parallel animal studies. METHOD Participants with normal audiograms were grouped according to Veteran status and tinnitus report (Veterans with tinnitus, Veterans without tinnitus, and non-Veteran controls). The effects of being a Veteran with tinnitus on ABR, MEMR, and EFR measurements were independently modeled using Bayesian regression analysis. RESULTS Modeled point estimates of MEMR and EFR magnitude showed reductions for Veterans with tinnitus compared with non-Veterans, with the most evident reduction observed for the EFR. Two different approaches were used to provide context for the Veteran tinnitus effect on the EFR by comparing to age-related reductions in EFR magnitude and synapse numbers observed in previous studies. These analyses suggested that EFR magnitude/synapse counts were reduced in Veterans with tinnitus by roughly the same amount as over 20 years of aging. CONCLUSION These findings suggest that cochlear synaptopathy may contribute to tinnitus perception in noise-exposed Veterans. SUPPLEMENTAL MATERIAL https://doi.org/10.23641/asha.24347761.
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Affiliation(s)
- Naomi F Bramhall
- VA RR&D National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, OR
- Department of Otolaryngology-Head & Neck Surgery, Oregon Health & Science University, Portland
| | - Sarah M Theodoroff
- VA RR&D National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, OR
- Department of Otolaryngology-Head & Neck Surgery, Oregon Health & Science University, Portland
| | - Garnett P McMillan
- VA RR&D National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, OR
| | - Sean D Kampel
- VA RR&D National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, OR
| | - Brad N Buran
- Department of Otolaryngology-Head & Neck Surgery, Oregon Health & Science University, Portland
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19
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Feng M, Zhou X, Hu Y, Zhang J, Yang T, Chen Z, Yuan W. Comprehensive Transcriptomic Profiling of m6A Modification in Age-Related Hearing Loss. Biomolecules 2023; 13:1537. [PMID: 37892219 PMCID: PMC10605720 DOI: 10.3390/biom13101537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/27/2023] [Accepted: 10/07/2023] [Indexed: 10/29/2023] Open
Abstract
Age-related hearing loss (ARHL), also known as presbycusis, is one of the most common neurodegenerative disorders in elderly individuals and has a prevalence of approximately 70-80% among individuals aged 65 and older. As ARHL is an intricate and multifactorial disease, the exact pathogenesis of ARHL is not fully understood. There is evidence that transcriptional dysregulation mediated by epigenetic modifications is widespread in ARHL. However, the potential role of N6-methyladenosine (m6A) modification, as a crucial component of epigenetics, in ARHL progression remains unclear. In this study, we confirmed that the downregulation of m6A modification in cochlear tissues is related to ARHL and found that the expression of the m6A methylation regulators Wilms tumour suppressor-1-associated protein (WTAP), methyltransferase-like 3 (METTL3), ALKB homologous protein 5 (ALKBH5) and fat mass and obesity-associated protein (FTO) is decreased significantly at the mRNA and protein levels in ARHL mice. Then, we used methylated RNA immunoprecipitation sequencing (MeRIP-Seq) and RNA sequencing (RNA-Seq) to identify the differentially m6A-methylated genes in the cochlear tissues of ARHL mice. A total of 3438 genes with differential m6A methylation were identified, of which 1332 genes were m6A-hypermethylated and 2106 genes were m6A-hypomethylated in the ARHL group compared to the control group according to MeRIP-seq. Further joint analysis of RNA-Seq and MeRIP-Seq data showed that 262 genes had significant differences in both mRNA expression and m6A methylation. GO and KEGG analyses indicated that 262 unique genes were enriched mainly in the PI3K-AKT signalling pathway. In conclusion, the results of this study reveal differential m6A methylation patterns in the cochlear tissues of ARHL mice, providing a theoretical basis for further study of the pathogenesis of ARHL and potential therapeutic strategies.
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Affiliation(s)
- Menglong Feng
- Chongqing Medical University, Chongqing 400016, China
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
- Department of Otolaryngology & Head and Neck, Chongqing General Hospital, Chongqing 401147, China
| | - Xiaoqing Zhou
- Department of Otolaryngology & Head and Neck, Chongqing General Hospital, Chongqing 401147, China
| | - Yaqin Hu
- Department of Otolaryngology & Head and Neck, Chongqing General Hospital, Chongqing 401147, China
| | - Juhong Zhang
- Department of Otolaryngology & Head and Neck, Chongqing General Hospital, Chongqing 401147, China
| | - Ting Yang
- Chongqing Medical University, Chongqing 400016, China
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
- Department of Otolaryngology & Head and Neck, Chongqing General Hospital, Chongqing 401147, China
| | - Zhiji Chen
- Department of Otolaryngology & Head and Neck, Chongqing General Hospital, Chongqing 401147, China
| | - Wei Yuan
- Chongqing Medical University, Chongqing 400016, China
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
- Department of Otolaryngology & Head and Neck, Chongqing General Hospital, Chongqing 401147, China
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20
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Liebscher T, Hornung J, Hoppe U. Electrically evoked compound action potentials in cochlear implant users with preoperative residual hearing. Front Hum Neurosci 2023; 17:1125747. [PMID: 37850038 PMCID: PMC10577430 DOI: 10.3389/fnhum.2023.1125747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 09/08/2023] [Indexed: 10/19/2023] Open
Abstract
Introduction Residual hearing in cochlear implant (CI) candidates requires the functional integrity of the nerve in particular regions of the cochlea. Nerve activity can be elicited as electrically evoked compound action potentials (ECAP) after cochlear implantation. We hypothesize that ECAP thresholds depend on preoperative residual hearing ability. Materials and methods In a retrospective study, we analyzed 84 adult cochlear implant users who had received a Nucleus® CI632 Slim Modiolar Electrode and who preoperatively had had residual hearing. Inclusion criteria were severe to profound hearing loss with preoperative measurable hearing in the ear to receive the implant, postlingual hearing loss, German as native language and correct placement of the electrode, inserted completely into the scala tympani. Electrically evoked compound action potential (ECAP) was recorded intraoperatively. The angular insertion was measured for each electrode contact from postoperative computed tomography to estimate the corresponding spiral ganglion frequency. Pure-tone audiometry and allocated ECAP thresholds were tested to investigate possible correlation. Results The average of hearing thresholds, tested at 0.5, 1, 2, and 4 kHz (4FPTA) was 82 ± 18 (range 47-129) dB HL. The success rate for recording ECAP thresholds was 96.9%. For all comparable pure-tone frequencies (1, 2, 4, and 8 kHz), there was significant correlation between preoperative hearing levels and intraoperative ECAP thresholds (p < 0.001). Higher hearing thresholds are associated with increased ECAP thresholds. Conclusion In CI candidates with adequate residual hearing, intraoperative electrophysiological measurement records lower thresholds. This outcome may be explained by the neural survival density of the peripheral system, with less neural degeneration.
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Affiliation(s)
- Tim Liebscher
- ENT-Clinic, Department of Audiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
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21
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Wang Y, Abrams KS, Youngman M, Henry KS. Histological Correlates of Auditory Nerve Injury from Kainic Acid in the Budgerigar (Melopsittacus undulatus). J Assoc Res Otolaryngol 2023; 24:473-485. [PMID: 37798548 PMCID: PMC10695905 DOI: 10.1007/s10162-023-00910-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/11/2023] [Indexed: 10/07/2023] Open
Abstract
PURPOSE Loss of auditory nerve afferent synapses with cochlear hair cells, called cochlear synaptopathy, is a common pathology in humans caused by aging and noise overexposure. The perceptual consequences of synaptopathy in isolation from other cochlear pathologies are still unclear. Animal models provide an effective approach to resolve uncertainty regarding the physiological and perceptual consequences of auditory nerve loss, because neural lesions can be induced and readily quantified. The budgerigar, a parakeet species, has recently emerged as an animal model for synaptopathy studies based on its capacity for vocal learning and ability to behaviorally discriminate simple and complex sounds with acuity similar to humans. Kainic acid infusions in the budgerigar produce a profound reduction of compound auditory nerve responses, including wave I of the auditory brainstem response, without impacting physiological hair cell measures. These results suggest selective auditory nerve damage. However, histological correlates of neural injury from kainic acid are still lacking. METHODS We quantified the histological effects caused by intracochlear infusion of kainic acid (1 mM; 2.5 µL), and evaluated correlations between the histological and physiological assessments of auditory nerve status. RESULTS Kainic acid infusion in budgerigars produced pronounced loss of neural auditory nerve soma (60% on average) in the cochlear ganglion, and of peripheral axons, at time points 2 or more months following injury. The hair cell epithelium was unaffected by kainic acid. Neural loss was significantly correlated with reduction of compound auditory nerve responses and auditory brainstem response wave I. CONCLUSION Compound auditory nerve responses and wave I provide a useful index of cochlear synaptopathy in this animal model.
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Affiliation(s)
- Yingxuan Wang
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14642, USA
| | - Kristina S Abrams
- Department of Neuroscience, University of Rochester, Rochester, NY 14642, USA
| | - Margaret Youngman
- Department of Otolaryngology, University of Rochester, Rochester, NY 14642, USA
| | - Kenneth S Henry
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14642, USA.
- Department of Neuroscience, University of Rochester, Rochester, NY 14642, USA.
- Department of Otolaryngology, University of Rochester, Rochester, NY 14642, USA.
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22
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Swords C, Geerardyn A, Zhu M, O'Malley JT, Wu P, Arenberg JG, Podury A, Brassett C, Bance M, Quesnel AM. Incomplete Partition Type II Cochlear Malformations: Delineating the Three-Dimensional Structure from Digitized Human Histopathological Specimens. Otol Neurotol 2023; 44:881-889. [PMID: 37621122 PMCID: PMC10803064 DOI: 10.1097/mao.0000000000003999] [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: 08/26/2023]
Abstract
HYPOTHESIS There are clinically relevant differences in scalae anatomy and spiral ganglion neuron (SGN) quantity between incomplete partition type II (IP-II) and normal cochleae. BACKGROUND IP-II is a commonly implanted cochlear malformation. Detailed knowledge of intracochlear three-dimensional (3D) morphology may assist with cochlear implant (CI) electrode selection/design and enable optimization of audiologic programming based on SGN maps. METHODS IP-II (n = 11) human temporal bone histological specimens were identified from the National Institute on Deafness and Other Communication Disorders National Temporal Bone Registry and digitized. The cochlear duct, scalae, and surgically relevant anatomy were reconstructed in 3D. A machine learning algorithm was applied to map the location and number of SGNs. RESULTS 3D scalae morphology of the basal turn was normal. Scala tympani (ST) remained isolated for 540 degrees before fusing with scala vestibuli. Mean ST volume reduced below 1 mm 2 after the first 340 degrees. Scala media was a distinct endolymphatic compartment throughout; mean ± standard deviation cochlear duct length was 28 ± 3 mm. SGNs were reduced compared with age-matched norms (mean, 48%; range, 5-90%). In some cases, SGNs failed to ascend Rosenthal's canal, remaining in an abnormal basalward modiolar location. Two forms of IP-II were seen: type A and type B. A majority (98-100%) of SGNs were located in the basal modiolus in type B IP-II, compared with 76 to 85% in type A. CONCLUSION Hallmark features of IP-II cochleae include the following: 1) fusion of the ST and scala vestibuli at a mean of 540 degrees, 2) highly variable and overall reduced SGN quantity compared with normative controls, and 3) abnormal SGN distribution with cell bodies failing to ascend Rosenthal's canal.
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Affiliation(s)
| | | | | | | | | | | | | | - Cecilia Brassett
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Manohar Bance
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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23
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Wu PZ, O'Malley JT, Liberman MC. Neural Degeneration in Normal-Aging Human Cochleas: Machine-Learning Counts and 3D Mapping in Archival Sections. J Assoc Res Otolaryngol 2023; 24:499-511. [PMID: 37957485 PMCID: PMC10695900 DOI: 10.1007/s10162-023-00909-y] [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: 01/12/2023] [Accepted: 09/03/2023] [Indexed: 11/15/2023] Open
Abstract
Quantifying the survival patterns of spiral ganglion cells (SGCs), the cell bodies of auditory-nerve fibers, is critical to studies of sensorineural hearing loss, especially in human temporal bones. The classic method of manual counting is tedious, and, although stereology approaches can be faster, they can only be used to estimate total cell numbers per cochlea. Here, a machine-learning algorithm that automatically identifies, counts, and maps the SGCs in digitized images of semi-serial human temporal-bone sections not only speeds the analysis, with no loss of accuracy, but also allows 3D visualization of the SGCs and fine-grained mapping to cochlear frequency. Applying the algorithm to 62 normal-aging human ears shows significantly faster degeneration of SGCs in the basal than the apical half of the cochlea. Comparison to fiber counts in the same ears shows that the fraction of surviving SGCs lacking a peripheral axon steadily increases with age, reaching more than 50% in the apical cochlea and almost 66% in basal regions.
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Affiliation(s)
- Pei-Zhe Wu
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114-3096, USA.
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02115, USA.
| | - Jennifer T O'Malley
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114-3096, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02115, USA
| | - M Charles Liberman
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114-3096, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02115, USA
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24
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Castelli V, d'Angelo M, Zazzeroni F, Vecchiotti D, Alesse E, Capece D, Brandolini L, Cattani F, Aramini A, Allegretti M, Cimini A. Intranasal delivery of NGF rescues hearing impairment in aged SAMP8 mice. Cell Death Dis 2023; 14:605. [PMID: 37704645 PMCID: PMC10499813 DOI: 10.1038/s41419-023-06100-8] [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: 06/19/2023] [Revised: 08/11/2023] [Accepted: 08/21/2023] [Indexed: 09/15/2023]
Abstract
Hearing loss impacts the quality of life and affects communication resulting in social isolation and reduced well-being. Despite its impact on society and economy, no therapies for age-related hearing loss are available so far. Loss of mechanosensory hair cells of the cochlea is a common event of hearing loss in humans. Studies performed in birds demonstrating that they can be replaced following the proliferation and transdifferentiation of supporting cells, strongly pointed out on HCs regeneration as the main focus of research aimed at hearing regeneration. Neurotrophins are growth factors involved in neuronal survival, development, differentiation, and plasticity. NGF has been involved in the interplay between auditory receptors and efferent innervation in the cochlea during development. During embryo development, both NGF and its receptors are highly expressed in the inner ears. It has been reported that NGF is implicated in the differentiation of auditory gangliar and hair cells. Thus, it has been proposed that NGF administration can decrease neuronal damage and prevent hearing loss. The main obstacle to the development of hearing impairment therapy is that efficient means of delivery for selected drugs to the cochlea are missing. Herein, in this study NGF was administered by the intranasal route. The first part of the study was focused on a biodistribution study, which showed the effective delivery in the cochlea; while the second part was focused on analyzing the potential therapeutic effect of NGF in senescence-accelerated prone strain 8 mice. Interestingly, intranasal administration of NGF resulted protective in counteracting hearing impairment in SAMP8 mice, ameliorating hearing performances (analyzed by auditory brainstem responses and distortion product otoacoustic emission) and hair cells morphology (analyzed by microscopy analysis). The results obtained were encouraging indicating that the neurotrophin NGF was efficiently delivered to the inner ear and that it was effective in counteracting hearing loss.
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Affiliation(s)
- Vanessa Castelli
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
| | - Michele d'Angelo
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
| | - Francesca Zazzeroni
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy.
| | - Davide Vecchiotti
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Edoardo Alesse
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Daria Capece
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | | | - Franca Cattani
- Dompé Farmaceutici Spa, Via Campo di Pile 1, L'Aquila, Italy
| | - Andrea Aramini
- Dompé Farmaceutici Spa, Via Campo di Pile 1, L'Aquila, Italy
| | | | - Annamaria Cimini
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
- Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Temple University, Philadelphia, PA, USA.
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Haggerty RA, Hutson KA, Riggs WJ, Brown KD, Pillsbury HC, Adunka OF, Buchman CA, Fitzpatrick DC. Assessment of cochlear synaptopathy by electrocochleography to low frequencies in a preclinical model and human subjects. Front Neurol 2023; 14:1104574. [PMID: 37483448 PMCID: PMC10361575 DOI: 10.3389/fneur.2023.1104574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 06/19/2023] [Indexed: 07/25/2023] Open
Abstract
Cochlear synaptopathy is the loss of synapses between the inner hair cells and the auditory nerve despite survival of sensory hair cells. The findings of extensive cochlear synaptopathy in animals after moderate noise exposures challenged the long-held view that hair cells are the cochlear elements most sensitive to insults that lead to hearing loss. However, cochlear synaptopathy has been difficult to identify in humans. We applied novel algorithms to determine hair cell and neural contributions to electrocochleographic (ECochG) recordings from the round window of animal and human subjects. Gerbils with normal hearing provided training and test sets for a deep learning algorithm to detect the presence of neural responses to low frequency sounds, and an analytic model was used to quantify the proportion of neural and hair cell contributions to the ECochG response. The capacity to detect cochlear synaptopathy was validated in normal hearing and noise-exposed animals by using neurotoxins to reduce or eliminate the neural contributions. When the analytical methods were applied to human surgical subjects with access to the round window, the neural contribution resembled the partial cochlear synaptopathy present after neurotoxin application in animals. This result demonstrates the presence of viable hair cells not connected to auditory nerve fibers in human subjects with substantial hearing loss and indicates that efforts to regenerate nerve fibers may find a ready cochlear substrate for innervation and resumption of function.
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Affiliation(s)
- Raymond A. Haggerty
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kendall A. Hutson
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - William J. Riggs
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
| | - Kevin D. Brown
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- University of North Carolina School of Medicine, Chapel Hill, NC, United States
| | - Harold C. Pillsbury
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- University of North Carolina School of Medicine, Chapel Hill, NC, United States
| | - Oliver F. Adunka
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
| | - Craig A. Buchman
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, United States
| | - Douglas C. Fitzpatrick
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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26
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Lang H, Noble KV, Barth JL, Rumschlag JA, Jenkins TR, Storm SL, Eckert MA, Dubno JR, Schulte BA. The Stria Vascularis in Mice and Humans Is an Early Site of Age-Related Cochlear Degeneration, Macrophage Dysfunction, and Inflammation. J Neurosci 2023; 43:5057-5075. [PMID: 37268417 PMCID: PMC10324995 DOI: 10.1523/jneurosci.2234-22.2023] [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: 12/05/2022] [Revised: 04/19/2023] [Accepted: 05/25/2023] [Indexed: 06/04/2023] Open
Abstract
Age-related hearing loss, or presbyacusis, is a common degenerative disorder affecting communication and quality of life for millions of older adults. Multiple pathophysiologic manifestations, along with many cellular and molecular alterations, have been linked to presbyacusis; however, the initial events and causal factors have not been clearly established. Comparisons of the transcriptome in the lateral wall (LW) with other cochlear regions in a mouse model (of both sexes) of "normal" age-related hearing loss revealed that early pathophysiological alterations in the stria vascularis (SV) are associated with increased macrophage activation and a molecular signature indicative of inflammaging, a common form of immune dysfunction. Structure-function correlation analyses in mice across the lifespan showed that the age-dependent increase in macrophage activation in the stria vascularis is associated with a decline in auditory sensitivity. High-resolution imaging analysis of macrophage activation in middle-aged and aged mouse and human cochleas, along with transcriptomic analysis of age-dependent changes in mouse cochlear macrophage gene expression, support the hypothesis that aberrant macrophage activity is an important contributor to age-dependent strial dysfunction, cochlear pathology, and hearing loss. Thus, this study highlights the SV as a primary site of age-related cochlear degeneration and aberrant macrophage activity and dysregulation of the immune system as early indicators of age-related cochlear pathology and hearing loss. Importantly, novel new imaging methods described here now provide a means to analyze human temporal bones in a way that had not previously been feasible and thereby represent a significant new tool for otopathological evaluation.SIGNIFICANCE STATEMENT Age-related hearing loss is a common neurodegenerative disorder affecting communication and quality of life. Current interventions (primarily hearing aids and cochlear implants) offer imperfect and often unsuccessful therapeutic outcomes. Identification of early pathology and causal factors is crucial for the development of new treatments and early diagnostic tests. Here, we find that the SV, a nonsensory component of the cochlea, is an early site of structural and functional pathology in mice and humans that is characterized by aberrant immune cell activity. We also establish a new technique for evaluating cochleas from human temporal bones, an important but understudied area of research because of a lack of well-preserved human specimens and difficult tissue preparation and processing approaches.
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Affiliation(s)
- Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kenyaria V Noble
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Jeremy L Barth
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Jeffrey A Rumschlag
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Tyreek R Jenkins
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Shelby L Storm
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Mark A Eckert
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Judy R Dubno
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Bradley A Schulte
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
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27
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Aedo-Sanchez C, Oliveros J, Aranguiz C, Muñoz C, Lazo-Maturana C, Aguilar-Vidal E. Subclinical hearing loss associated with aging. J Otol 2023; 18:111-117. [PMID: 37497327 PMCID: PMC10366586 DOI: 10.1016/j.joto.2023.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 05/09/2023] [Accepted: 05/15/2023] [Indexed: 07/28/2023] Open
Abstract
Objective Contribute to clarifying the existence of subclinical hearing deficits associated with aging. Design In this work, we study and compare the auditory perceptual and electrophysiological performance of normal-hearing young and adult subjects (tonal audiometry, high-frequency tone threshold, a triplet of digits in noise, and click-evoked auditory brainstem response). Study sample 45 normal hearing volunteers were evaluated and divided into two groups according to age. 27 subjects were included in the "young group" (mean 22.1 years), and 18 subjects (mean 42.22 years) were included in the "adult group." Results In the perceptual tests, the adult group presented significantly worse tonal thresholds in the high frequencies (12 and 16 kHz) and worse performance in the digit triplet tests in noise. In the electrophysiological test using the auditory brainstem response technique, the adult group presented significantly lower I and V wave amplitudes and higher V wave latencies at the supra-threshold level. At the threshold level, we observed a significantly higher latency in wave V in the adult group. In addition, in the partial correlation analysis, controlling for the hearing level, we observed a relationship (negative) between age and speech in noise performance and high-frequency thresholds. No significant association was observed between age and the auditory brainstem response. Conclusion The results are compatible with subclinical hearing loss associated with aging.
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Affiliation(s)
- Cristian Aedo-Sanchez
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Chile
| | - José Oliveros
- Escuela de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Chile
| | - Constanza Aranguiz
- Escuela de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Chile
| | - Camila Muñoz
- Escuela de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Chile
| | - Claudia Lazo-Maturana
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Chile
| | - Enzo Aguilar-Vidal
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Chile
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28
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Hockley A, Cassinotti LR, Selesko M, Corfas G, Shore SE. Cochlear synaptopathy impairs suprathreshold tone-in-noise coding in the cochlear nucleus. J Physiol 2023; 601:2991-3006. [PMID: 37212296 PMCID: PMC10374284 DOI: 10.1113/jp284452] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 05/16/2023] [Indexed: 05/23/2023] Open
Abstract
Hearing impairment without threshold elevations can occur when there is damage to high-threshold auditory nerve fibre synapses with cochlear inner hair cells. Instead, cochlear synaptopathy produces suprathreshold deficits, especially in older patients, which affect conversational speech. Given that listening in noise at suprathreshold levels presents significant challenges to the ageing population, we examined the effects of synaptopathy on tone-in-noise coding on the central recipients of auditory nerve fibres, i.e. the cochlear nucleus neurons. To induce synaptopathy, guinea pigs received a unilateral sound overexposure to the left ears. A separate group received sham exposures. At 4 weeks post-exposure, thresholds had recovered but reduced auditory brainstem response wave 1 amplitudes and auditory nerve synapse loss remained on the left side. Single-unit responses were recorded from several cell types in the ventral cochlear nucleus to pure-tone and noise stimuli. Receptive fields and rate-level functions in the presence of continuous broadband noise were examined. The synaptopathy-inducing noise exposure did not affect mean unit tone-in-noise thresholds, nor the tone-in-noise thresholds in each animal, demonstrating equivalent tone-in-noise detection thresholds to sham animals. However, synaptopathy reduced single-unit responses to suprathreshold tones in the presence of background noise, particularly in the cochlear nucleus small cells. These data demonstrate that suprathreshold tone-in-noise deficits following cochlear synaptopathy are evident in the first neural station of the auditory brain, the cochlear nucleus neurons, and provide a potential target for assessment and treatment of listening-in-noise deficits in humans. KEY POINTS: Recording from multiple central auditory neurons can determine tone-in-noise deficits in animals with quantified cochlear synapse damage. Using this technique, we found that tone-in-noise thresholds are not altered by cochlear synaptopathy, whereas coding of suprathreshold tones-in-noise is disrupted. Suprathreshold deficits occur in small cells and primary-like neurons of the cochlear nucleus. These data provide important insights into the mechanisms underlying difficulties associated with hearing in noisy environments.
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Affiliation(s)
- A Hockley
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI, USA
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
| | - L R Cassinotti
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI, USA
| | - M Selesko
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI, USA
| | - G Corfas
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI, USA
| | - S E Shore
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
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29
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Tan SL, Chen YF, Liu CY, Chu KC, Li PC. Shortened neural conduction time in young adults with tinnitus as revealed by chirp-evoked auditory brainstem response. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:2178. [PMID: 37092912 DOI: 10.1121/10.0017789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 03/23/2023] [Indexed: 05/03/2023]
Abstract
Tinnitus is generally considered to be caused by neuroplastic changes in the central nervous system, triggered by a loss of input from the damaged peripheral system; however, conflicting results on auditory brainstem responses (ABRs) to clicks have been reported previously in humans with tinnitus. This study aimed to compare the effect of tinnitus on ABRs to chirps with those to clicks in normal-hearing young adults with tinnitus. The results showed that the tinnitus group had no significantly poorer hearing thresholds (0.25-16 kHz), click-evoked otoacoustic emissions (1-16 kHz), and speech perception in noise (SPIN) than the control group. Although chirps evoked significantly larger wave I and V amplitudes than clicks, people with tinnitus had no significantly smaller wave I amplitudes for either stimulus. Nevertheless, adults with tinnitus exhibited significantly smaller interpeak interval (IPI) between waves I and V for chirps (IPI-chirp) but not for clicks. In addition, the IPI-chirp correlated significantly with the SPIN for individuals with tinnitus when the signal-to-noise ratio was low. The present results suggest that the chirp-evoked ABR may be a valuable clinical tool for objectively assessing the SPIN in individuals with tinnitus. Further studies should be conducted to investigate possible etiologies of tinnitus.
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Affiliation(s)
- See Ling Tan
- Department of Speech-Language Pathology and Audiology, National Taipei University of Nursing and Health Sciences, Number 365, Mingde Road, Beitou District, Taipei City 112303, Taiwan
| | - Yu-Fu Chen
- Department of Speech-Language Pathology and Audiology, National Taipei University of Nursing and Health Sciences, Number 365, Mingde Road, Beitou District, Taipei City 112303, Taiwan
| | - Chieh-Yu Liu
- Department of Health Care Management, National Taipei University of Nursing and Health Sciences, Number 365, Mingde Road, Beitou District, Taipei City 112303, Taiwan
| | - Kuo-Chung Chu
- Department of Information Management, National Taipei University of Nursing and Health Sciences, Number 365, Mingde Road, Beitou District, Taipei City 112303, Taiwan
| | - Pei-Chun Li
- Department of Audiology and Speech-Language Pathology, MacKay Medical College, Number 46, Section 3, Zhongzheng Road, Sanzhi District, New Taipei City 25245, Taiwan
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30
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Brennan MA, Svec A, Farhadi A, Maxwell BN, Carney LH. Inherent envelope fluctuations in forward masking: Effects of age and hearing loss. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:1994. [PMID: 37092921 PMCID: PMC10071988 DOI: 10.1121/10.0017724] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 05/03/2023]
Abstract
Forward masking is generally greater for Gaussian noise (GN) than for low-fluctuation noise maskers, i.e., GN disruption. Because the minimal hearing loss that is associated with older age may affect GN disruption differently than more significant hearing loss, the current study explored the contribution of minimal hearing loss associated with older age to GN disruption. GN disruption was measured using three masker-signal delays (25, 75, and 150 ms) for three adult groups: younger participants with normal hearing (NH), older participants with minimal hearing loss, and older participants with sensorineural hearing loss. The role of underlying mechanisms was tested using a computational model for midbrain neurons. The primary result suggests that older listeners with mild threshold elevations that typically occur with age may be more susceptible to the deleterious effects of masker envelope fluctuations than younger listeners with NH. Results from the computational model indicate that there may be a larger influence of efferent feedback and saturation of inner hair cells on forward masking and GN disruption than previously considered.
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Affiliation(s)
- Marc A Brennan
- University of Nebraska-Lincoln, Lincoln, Nebraska 68583, USA
| | - Adam Svec
- San José State University, San Jose, California 95192, USA
| | - Afagh Farhadi
- University of Rochester, Rochester, New York 14642, USA
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Nisha KV, Uppunda AK, Konadath S. Effects of Maturation and Chronological Aging on Auditory Spatial Processing: A Cross-Sectional Study Across Life Span. Am J Audiol 2023; 32:119-134. [PMID: 36548963 DOI: 10.1044/2022_aja-22-00113] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE The primary aim of the research was to document spatial acuity changes across the life span using a battery of psychoacoustical and perceptual tests. The secondary aim was to identify the optimal metric for measuring spatial processing changes across the life span (ages 10-70 years). DESIGN AND STUDY SAMPLE A cross-sectional study comprising 115 participants with clinically normal hearing was conducted. Purposive sampling was adopted to recruit participants in the study, who were divided into six groups based on their chronological age. METHOD Temporal, intensity, spectral, and composite correlates of spatial acuity were assessed using psychoacoustic measures and perceptual questionnaires. The temporal (interaural time difference [ITD]) and intensity correlates (interaural level difference [ILD]) of spatial perception were obtained using a MATLAB (v 2020a), whereas the composite correlate (virtual auditory space identification scores [VASIs]) and perceptual ratings of spatial processing were measured using Paradigm software and speech spatial and qualities in Kannada (SSQ-K). RESULTS Results across all tests (multivariate analyses variance: 6 age groups × 4 tests, followed by post hoc tests) consistently demonstrate poor ITD and ILD thresholds and overall lower spatial accuracy (VASI, SSQ-K) with increasing age. Discriminant function analyses (DFAs) revealed that VASI had a higher predictive power in capturing age-related changes in auditory spatial processing. The group segregation on spatial performance in DFA became evident after 50 years. CONCLUSION This study provides evidence of gradual change in all three correlates of spatial processing, with statistically demonstrable deficits appearing from fourth decade of life on VASI and fifth decade of life on binaural processing.
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Affiliation(s)
| | - Ajith Kumar Uppunda
- Department of Audiology, All India Institute of Speech and Hearing, Manasagangothri, Mysuru
| | - Sreeraj Konadath
- Department of Audiology, All India Institute of Speech and Hearing, Manasagangothri, Mysuru
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Papesh MA, Fowler L, Pesa SR, Frederick MT. Functional Hearing Difficulties in Veterans: Retrospective Chart Review of Auditory Processing Assessments in the VA Health Care System. Am J Audiol 2023; 32:101-118. [PMID: 36599099 DOI: 10.1044/2022_aja-22-00117] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PURPOSE Approximately 23 million Americans might have functional hearing difficulties (FHDs) that are not well explained by their audiometric thresholds. Clinical management of patients with FHDs is the subject of considerable debate, with few evidence-based guidelines to direct patient care. A better understanding of the characteristics of patients who seek help for FHDs, as well as current audiological management practices, is needed to direct research efforts to the areas greatest opportunity for advancement of clinical care. METHOD A retrospective chart review was conducted examining the medical records of a random sample of 100 Veterans who underwent auditory processing assessments across the VA Health Care System between 2008 and 2020. RESULTS Patients were young to middle-age, often with previous traumatic brain injury or blast exposure. Mental health, sleep, and pain disorders were common. No consistent relationships emerged between specific patient factors and domains of auditory processing deficits. Low-gain hearing aids were provided to 35 patients, 69% of whom continued wearing their hearing aids for at least 2 years. CONCLUSION Future research should address the potential overlap in symptoms and treatment for comorbid health conditions and FHDs, as well as the conditions underlying successful hearing aid use in this patient population.
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Affiliation(s)
- Melissa A Papesh
- VA RR&D National Center for Rehabilitative Auditory Research, VA Portland Health Care System, OR
- Department of Otolaryngology - Head and Neck Surgery, Oregon Health and Science University, Portland
| | - Lora Fowler
- Department of Communication Sciences and Disorders, Idaho State University, Pocatello
| | - Stephanie R Pesa
- VA Portland Audiology and Speech and Language Pathology Service, VA Portland Health Care System, OR
| | - Melissa T Frederick
- VA RR&D National Center for Rehabilitative Auditory Research, VA Portland Health Care System, OR
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Millet B, Snapp HA, Rajguru SM, Schaefer Solle N. Prevalence of Hearing Loss and Perceptions of Hearing Health and Protection among Florida Firefighters. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3826. [PMID: 36900832 PMCID: PMC10001319 DOI: 10.3390/ijerph20053826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/05/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
Firefighters are exposed to extensive hazardous noise while on the job, both during routine tasks at the station and when responding to calls. However, little is known about firefighters' occupational noise hazards. This study employed mixed methods, including focus groups, a survey, and audiometric testing, to identify sources of noise in the firefighters' work environment, determine hearing protective strategies, discern firefighters' perceptions of occupational noise exposure and impacts to their health, and quantify the prevalence of hearing loss among South Florida firefighters. A total of 6 senior officers served in an expert panel, 12 participated in focus groups, 300 completed the survey, and 214 received audiometric tests. Most firefighters were unaware of the risk and their departments' policies, and did not participate in hearing protection practices and avoided using hearing protection devices, which they believed impede team communication and situational awareness. Nearly 30% of participating firefighters showed mild to profound hearing loss, a prevalence that is considerably worse than expected by normal aging alone. Educating firefighters about noise-induced hearing loss early in their careers may have significant health implications for their future. These findings provide insights for developing technologies and programs to mitigate the effects of noise exposure in the firefighting population.
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Affiliation(s)
- Barbara Millet
- Department of Interactive Media, University of Miami, Miami, FL 33136, USA
| | - Hillary A. Snapp
- Department of Otolaryngology, University of Miami, Miami, FL 33136, USA
| | - Suhrud M. Rajguru
- Department of Otolaryngology, University of Miami, Miami, FL 33136, USA
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL 33136, USA
- RestorEar Devices LLC, Bozeman, MT 59715, USA
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Perugia E, Marmel F, Kluk K. Feasibility of Diagnosing Dead Regions Using Auditory Steady-State Responses to an Exponentially Amplitude Modulated Tone in Threshold Equalizing Notched Noise, Assessed Using Normal-Hearing Participants. Trends Hear 2023; 27:23312165231173234. [PMID: 37384583 PMCID: PMC10336760 DOI: 10.1177/23312165231173234] [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: 12/15/2021] [Revised: 04/11/2023] [Accepted: 04/14/2023] [Indexed: 07/01/2023] Open
Abstract
The aim of this study was to assess feasibility of using electrophysiological auditory steady-state response (ASSR) masking for detecting dead regions (DRs). Fifteen normally hearing adults were tested using behavioral and electrophysiological tasks. In the electrophysiological task, ASSRs were recorded to a 2 kHz exponentially amplitude-modulated tone (AM2) presented within a notched threshold equalizing noise (TEN) whose center frequency (CFNOTCH) varied. We hypothesized that, in the absence of DRs, ASSR amplitudes would be largest for CFNOTCH at/or near the signal frequency. In the presence of a DR at the signal frequency, the largest ASSR amplitude would occur at a frequency (fmax) far away from the signal frequency. The AM2 and the TEN were presented at 60 and 75 dB SPL, respectively. In the behavioral task, for the same maskers as above, the masker level at which an AM and a pure tone could just be distinguished, denoted AM2ML, was determined, for low (10 dB above absolute AM2 threshold) and high (60 dB SPL) signal levels. We also hypothesized that the value of fmax would be similar for both techniques. The ASSR fmax values obtained from grand average ASSR amplitudes, but not from individual amplitudes, were consistent with our hypotheses. The agreement between the behavioral fmax and ASSR fmax was poor. The within-session ASSR-amplitude repeatability was good for AM2 alone, but poor for AM2 in notched TEN. The ASSR-amplitude variability between and within participants seems to be a major roadblock to developing our approach into an effective DR detection method.
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Affiliation(s)
- Emanuele Perugia
- Manchester Centre for Audiology and Deafness, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Frederic Marmel
- Manchester Centre for Audiology and Deafness, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Karolina Kluk
- Manchester Centre for Audiology and Deafness, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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Van Der Biest H, Keshishzadeh S, Keppler H, Dhooge I, Verhulst S. Envelope following responses for hearing diagnosis: Robustness and methodological considerations. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:191. [PMID: 36732231 DOI: 10.1121/10.0016807] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
Recent studies have found that envelope following responses (EFRs) are a marker of age-related and noise- or ototoxic-induced cochlear synaptopathy (CS) in research animals. Whereas the cochlear injury can be well controlled in animal research studies, humans may have an unknown mixture of sensorineural hearing loss [SNHL; e.g., inner- or outer-hair-cell (OHC) damage or CS] that cannot be teased apart in a standard hearing evaluation. Hence, a direct translation of EFR markers of CS to a differential CS diagnosis in humans might be compromised by the influence of SNHL subtypes and differences in recording modalities between research animals and humans. To quantify the robustness of EFR markers for use in human studies, this study investigates the impact of methodological considerations related to electrode montage, stimulus characteristics, and presentation, as well as analysis method on human-recorded EFR markers. The main focus is on rectangularly modulated pure-tone stimuli to evoke the EFR based on a recent auditory modelling study that showed that the EFR was least affected by OHC damage and most sensitive to CS in this stimulus configuration. The outcomes of this study can help guide future clinical implementations of electroencephalography-based SNHL diagnostic tests.
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Affiliation(s)
- Heleen Van Der Biest
- Hearing Technology at Wireless, Acoustics, Environment and Expert Systems, Department of Information Technology, Ghent, Belgium
| | - Sarineh Keshishzadeh
- Hearing Technology at Wireless, Acoustics, Environment and Expert Systems, Department of Information Technology, Ghent, Belgium
| | - Hannah Keppler
- Department of Rehabilitation Sciences-Audiology, Ghent University, Ghent, Belgium
| | - Ingeborg Dhooge
- Department of Head and Skin, Ghent University, Ghent, Belgium
| | - Sarah Verhulst
- Hearing Technology at Wireless, Acoustics, Environment and Expert Systems, Department of Information Technology, Ghent, Belgium
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Gómez-Álvarez M, Johannesen PT, Coelho-de-Sousa SL, Klump GM, Lopez-Poveda EA. The Relative Contribution of Cochlear Synaptopathy and Reduced Inhibition to Age-Related Hearing Impairment for People With Normal Audiograms. Trends Hear 2023; 27:23312165231213191. [PMID: 37956654 PMCID: PMC10644751 DOI: 10.1177/23312165231213191] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
Older people often show auditory temporal processing deficits and speech-in-noise intelligibility difficulties even when their audiogram is clinically normal. The causes of such problems remain unclear. Some studies have suggested that for people with normal audiograms, age-related hearing impairments may be due to a cognitive decline, while others have suggested that they may be caused by cochlear synaptopathy. Here, we explore an alternative hypothesis, namely that age-related hearing deficits are associated with decreased inhibition. For human adults (N = 30) selected to cover a reasonably wide age range (25-59 years), with normal audiograms and normal cognitive function, we measured speech reception thresholds in noise (SRTNs) for disyllabic words, gap detection thresholds (GDTs), and frequency modulation detection thresholds (FMDTs). We also measured the rate of growth (slope) of auditory brainstem response wave-I amplitude with increasing level as an indirect indicator of cochlear synaptopathy, and the interference inhibition score in the Stroop color and word test (SCWT) as a proxy for inhibition. As expected, performance in the auditory tasks worsened (SRTNs, GDTs, and FMDTs increased), and wave-I slope and SCWT inhibition scores decreased with ageing. Importantly, SRTNs, GDTs, and FMDTs were not related to wave-I slope but worsened with decreasing SCWT inhibition. Furthermore, after partialling out the effect of SCWT inhibition, age was no longer related to SRTNs or GDTs and became less strongly related to FMDTs. Altogether, results suggest that for people with normal audiograms, age-related deficits in auditory temporal processing and speech-in-noise intelligibility are mediated by decreased inhibition rather than cochlear synaptopathy.
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Affiliation(s)
- Marcelo Gómez-Álvarez
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Peter T. Johannesen
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Sónia L. Coelho-de-Sousa
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Georg M. Klump
- Department of Neuroscience and Cluster of Excellence “Hearing4all”, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Enrique A. Lopez-Poveda
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
- Departamento de Cirugía, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain
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Modeling temporal information encoding by the population of fibers in the healthy and synaptopathic auditory nerve. Hear Res 2022; 426:108621. [PMID: 36182814 DOI: 10.1016/j.heares.2022.108621] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 09/16/2022] [Accepted: 09/20/2022] [Indexed: 11/23/2022]
Abstract
We report a theoretical study aimed at investigating the impact of cochlear synapse loss (synaptopathy) on the encoding of the envelope (ENV) and temporal fine structure (TFS) of sounds by the population of auditory nerve fibers. A computational model was used to simulate auditory-nerve spike trains evoked by sinusoidally amplitude-modulated (AM) tones at 10 Hz with various carrier frequencies and levels. The model included 16 cochlear channels with characteristic frequencies (CFs) from 250 Hz to 8 kHz. Each channel was innervated by 3, 4 and 10 fibers with low (LSR), medium (MSR), and high spontaneous rates (HSR), respectively. For each channel, spike trains were collapsed into three separate 'population' post-stimulus time histograms (PSTHs), one per fiber type. Information theory was applied to reconstruct the stimulus waveform, ENV, and TFS from one or more PSTHs in a mathematically optimal way. The quality of the reconstruction was regarded as an estimate of the information present in the used PSTHs. Various synaptopathy scenarios were simulated by removing fibers of specific types and/or cochlear regions before stimulus reconstruction. We found that the TFS was predominantly encoded by HSR fibers at all stimulus carrier frequencies and levels. The encoding of the ENV was more complex. At lower levels, the ENV was predominantly encoded by HSR fibers with CFs near the stimulus carrier frequency. At higher levels, the ENV was equally well or better encoded by HSR fibers with CFs different from the AM carrier frequency as by LSR fibers with CFs at the carrier frequency. Altogether, findings suggest that a healthy population of HSR fibers (i.e., including fibers with CFs around and remote from the AM carrier frequency) might be sufficient to encode the ENV and TFS over a wide range of stimulus levels. Findings are discussed regarding their relevance for diagnosing synaptopathy using non-invasive ENV- and TFS-based measures.
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Comparison of response properties of the electrically stimulated auditory nerve reported in human listeners and in animal models. Hear Res 2022; 426:108643. [PMID: 36343534 PMCID: PMC9986845 DOI: 10.1016/j.heares.2022.108643] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/29/2022] [Accepted: 10/20/2022] [Indexed: 11/04/2022]
Abstract
Cochlear implants (CIs) provide acoustic information to implanted patients by electrically stimulating nearby auditory nerve fibers (ANFs) which then transmit the information to higher-level neural structures for further processing and interpretation. Computational models that simulate ANF responses to CI stimuli enable the exploration of the mechanisms underlying CI performance beyond the capacity of in vivo experimentation alone. However, all ANF models developed to date utilize to some extent anatomical/morphometric data, biophysical properties and/or physiological data measured in non-human animal models. This review compares response properties of the electrically stimulated auditory nerve (AN) in human listeners and different mammalian models. Properties of AN responses to single pulse stimulation, paired-pulse stimulation, and pulse-train stimulation are presented. While some AN response properties are similar between human listeners and animal models (e.g., increased AN sensitivity to single pulse stimuli with long interphase gaps), there are some significant differences. For example, the AN of most animal models is typically more sensitive to cathodic stimulation while the AN of human listeners is generally more sensitive to anodic stimulation. Additionally, there are substantial differences in the speed of recovery from neural adaptation between animal models and human listeners. Therefore, results from animal models cannot be simply translated to human listeners. Recognizing the differences in responses of the AN to electrical stimulation between humans and other mammals is an important step for creating ANF models that are more applicable to various human CI patient populations.
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Bommakanti KK, Iyer JS, Sagi V, Brown A, Ma X, Gonzales M, Stankovic KM. Reversible contrast enhancement for visualization of human temporal bones using micro computed tomography. Front Surg 2022; 9:952348. [PMID: 36268215 PMCID: PMC9577409 DOI: 10.3389/fsurg.2022.952348] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 09/08/2022] [Indexed: 11/13/2022] Open
Abstract
Sensorineural hearing loss (SNHL), which typically arises from the inner ear, is the most common sensory deficit worldwide. The traditional method for studying pathophysiology underlying human SNHL involves histological processing of the inner ear from temporal bones collected during autopsy. Histopathological analysis is destructive and limits future use of a given specimen. Non-destructive strategies for the study of the inner ear are urgently needed to fully leverage the utility of each specimen because access to human temporal bones is increasingly difficult and these precious specimens are required to uncover disease mechanisms and to enable development of new devices. We highlight the potential of reversible iodine staining for micro-computed tomography imaging of the human inner ear. This approach provides reversible, high-resolution visualization of intracochlear structures and is becoming more rapid and accessible.
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Affiliation(s)
- Krishna K. Bommakanti
- Department of Head / Neck Surgery, University of California Los Angeles, Los Angeles, CA, United States,Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
| | - Janani S. Iyer
- Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States,Department of Otolaryngology, Harvard Medical School, Boston, MA, United States,Program in Speech and Hearing Bioscience and Technology, Harvard University Graduate School of Arts and Sciences, Cambridge, MA, United States
| | - Varun Sagi
- Department of Otolaryngology – Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States,University of Minnesota Medical School, Minneapolis, MN, United States
| | - Alyssa Brown
- Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
| | - Xiaojie Ma
- Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States,Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
| | - Marissa Gonzales
- Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
| | - Konstantina M. Stankovic
- Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States,Department of Otolaryngology, Harvard Medical School, Boston, MA, United States,Department of Otolaryngology – Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States,Correspondence: Konstantina M. Stankovic
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40
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Pinsonnault-Skvarenina A, Soucy W, Noël J, Doucet F, Lévesque É, Fuente A, Leroux T. Supra-threshold deficits in normal hearing military recruits exposed to impulse noise. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:2419. [PMID: 36319241 DOI: 10.1121/10.0014829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
The aim of this study was to determine the effect of impulse noise exposure on various proxy measures of cochlear synaptopathy in young military recruits. A total of 27 military recruits with exposure to firearm and artillery noise and 13 non exposed participants were recruited. All presented with normal hearing thresholds and the presence of distortion product otoacoustic emissions (DPOAEs). The Noise Exposure Structured Interview (NESI) was used to quantify noise exposure. Speech perception in noise (SPiN), equivalent rectangular bandwidth (ERB) of auditory filters, auditory brainstem response wave I amplitude, wave I amplitude growth function, wave I/V amplitude ratio, wave V latency, wave V latency shift with ipsilateral noise, and the summating potential/action potential ratio of the electrocochleography were measured. In military participants, SPiN was worse, ERB at 4 kHz was larger, wave I amplitude at 75 dBnHL was reduced, and wave V latency was delayed. However, no significant correlations were observed between NESI and auditory measures, once multiplicity of tests was controlled for. These results suggest that military recruits may exhibit supra-threshold deficits, despite presenting with normal hearing thresholds and presence of DPOAEs. Future studies should include a measure of auditory filters in their test battery.
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Affiliation(s)
| | - William Soucy
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Jonathan Noël
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Félicia Doucet
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Élise Lévesque
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Adrian Fuente
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Tony Leroux
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
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Tinnemore AR, Montero L, Gordon-Salant S, Goupell MJ. The recognition of time-compressed speech as a function of age in listeners with cochlear implants or normal hearing. Front Aging Neurosci 2022; 14:887581. [PMID: 36247992 PMCID: PMC9557069 DOI: 10.3389/fnagi.2022.887581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Speech recognition is diminished when a listener has an auditory temporal processing deficit. Such deficits occur in listeners over 65 years old with normal hearing (NH) and with age-related hearing loss, but their source is still unclear. These deficits may be especially apparent when speech occurs at a rapid rate and when a listener is mostly reliant on temporal information to recognize speech, such as when listening with a cochlear implant (CI) or to vocoded speech (a CI simulation). Assessment of the auditory temporal processing abilities of adults with CIs across a wide range of ages should better reveal central or cognitive sources of age-related deficits with rapid speech because CI stimulation bypasses much of the cochlear encoding that is affected by age-related peripheral hearing loss. This study used time-compressed speech at four different degrees of time compression (0, 20, 40, and 60%) to challenge the auditory temporal processing abilities of younger, middle-aged, and older listeners with CIs or with NH. Listeners with NH were presented vocoded speech at four degrees of spectral resolution (unprocessed, 16, 8, and 4 channels). Results showed an interaction between age and degree of time compression. The reduction in speech recognition associated with faster rates of speech was greater for older adults than younger adults. The performance of the middle-aged listeners was more similar to that of the older listeners than to that of the younger listeners, especially at higher degrees of time compression. A measure of cognitive processing speed did not predict the effects of time compression. These results suggest that central auditory changes related to the aging process are at least partially responsible for the auditory temporal processing deficits seen in older listeners, rather than solely peripheral age-related changes.
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Affiliation(s)
- Anna R. Tinnemore
- Neuroscience and Cognitive Science Program, University of Maryland, College Park, College Park, MD, United States
- Department of Hearing and Speech Sciences, University of Maryland, College Park, College Park, MD, United States
- *Correspondence: Anna R. Tinnemore,
| | - Lauren Montero
- Department of Hearing and Speech Sciences, University of Maryland, College Park, College Park, MD, United States
| | - Sandra Gordon-Salant
- Neuroscience and Cognitive Science Program, University of Maryland, College Park, College Park, MD, United States
- Department of Hearing and Speech Sciences, University of Maryland, College Park, College Park, MD, United States
| | - Matthew J. Goupell
- Neuroscience and Cognitive Science Program, University of Maryland, College Park, College Park, MD, United States
- Department of Hearing and Speech Sciences, University of Maryland, College Park, College Park, MD, United States
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Tarawneh HY, Jayakody DM, Sohrabi HR, Martins RN, Mulders WH. Understanding the Relationship Between Age-Related Hearing Loss and Alzheimer’s Disease: A Narrative Review. J Alzheimers Dis Rep 2022; 6:539-556. [PMID: 36275417 PMCID: PMC9535607 DOI: 10.3233/adr-220035] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 08/16/2022] [Indexed: 12/02/2022] Open
Abstract
Evidence suggests that hearing loss (HL), even at mild levels, increases the long-term risk of cognitive decline and incident dementia. Hearing loss is one of the modifiable risk factors for dementia, with approximately 4 million of the 50 million cases of dementia worldwide possibly attributed to untreated HL. This paper describes four possible mechanisms that have been suggested for the relationship between age-related hearing loss (ARHL) and Alzheimer’s disease (AD), which is the most common form of dementia. The first mechanism suggests mitochondrial dysfunction and altered signal pathways due to aging as a possible link between ARHL and AD. The second mechanism proposes that sensory degradation in hearing impaired people could explain the relationship between ARHL and AD. The occupation of cognitive resource (third) mechanism indicates that the association between ARHL and AD is a result of increased cognitive processing that is required to compensate for the degraded sensory input. The fourth mechanism is an expansion of the third mechanism, i.e., the function and structure interaction involves both cognitive resource occupation (neural activity) and AD pathology as the link between ARHL and AD. Exploring the specific mechanisms that provide the link between ARHL and AD has the potential to lead to innovative ideas for the diagnosis, prevention, and/or treatment of AD. This paper also provides insight into the current evidence for the use of hearing treatments as a possible treatment/prevention for AD, and if auditory assessments could provide an avenue for early detection of cognitive impairment associated with AD.
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Affiliation(s)
- Hadeel Y. Tarawneh
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia
- Ear Science Institute Australia, Subiaco, WA, Australia
| | - Dona M.P. Jayakody
- Ear Science Institute Australia, Subiaco, WA, Australia
- Centre of Ear Science, Medical School, The University of Western Australia, Crawley, WA, Australia
| | - Hamid R. Sohrabi
- Centre for Healthy Ageing, College of Science, Health, Engineering and Education, Murdoch University, WA, Australia
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, NSW, Australia
| | - Ralph N. Martins
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, NSW, Australia
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Kaf WA, Turntine M, Jamos A, Smurzynski J. Examining the Profile of Noise-Induced Cochlear Synaptopathy Using iPhone Health App Data and Cochlear and Brainstem Electrophysiological Responses to Fast Clicks Rates. Semin Hear 2022; 43:197-222. [PMID: 36313044 PMCID: PMC9605806 DOI: 10.1055/s-0042-1756164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Little is known about objective classifying of noise exposure risk levels in personal listening device (PLD) users and electrophysiologic evidence of cochlear synaptopathy at very fast click rates. The aim of the study was to objectively classify noise exposure risk using iPhone Health app and identify signs of cochlear synaptopathy using behavioral and electrophysiologic measures. Thirty normal-hearing females (aged 18-26 years) were grouped based on their iPhone Health app's 6-month listening level and noise exposure data into low-risk and high-risk groups. They were assessed using a questionnaire, extended high-frequency (EHF) audiometry, QuickSIN test, distortion-product otoacoustic emission (DPOAE), and simultaneous recording of electrocochleography (ECochG) and auditory brainstem response (ABR) at three click rates (19.5/s, 97.7/s, 234.4/s). A series of ANOVAs and independent samples t -test were conducted for group comparison. Both groups had within-normal EHF hearing thresholds and DPOAEs. However, the high-risk participants were over twice as likely to suffer from tinnitus, had abnormally large summating potential to action potential amplitude and area ratios at fast rates, and had slightly smaller waves I and V amplitudes. The high-risk group demonstrated a profile of behavioral and objective signs of cochlear synaptopathy based on ECochG and ABR recordings at fast click rates. The findings in this study suggest that the iPhone Health app may be a useful tool for further investigation into cochlear synaptopathy in PLD users.
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Affiliation(s)
- Wafaa A. Kaf
- Department of Communication Sciences and Disorders, Missouri State University, Springfield, Missouri
| | - Madison Turntine
- Department of Communication Sciences and Disorders, Missouri State University, Springfield, Missouri
| | - Abdullah Jamos
- Department of Communication Sciences and Disorders, Missouri State University, Springfield, Missouri
| | - Jacek Smurzynski
- Department of Audiology and Speech-Language Pathology, East Tennessee State University, Johnson City, Tennessee
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Rumschlag JA, McClaskey CM, Dias JW, Kerouac LB, Noble KV, Panganiban C, Lang H, Harris KC. Age-related central gain with degraded neural synchrony in the auditory brainstem of mice and humans. Neurobiol Aging 2022; 115:50-59. [PMID: 35468552 PMCID: PMC9153923 DOI: 10.1016/j.neurobiolaging.2022.03.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/18/2022] [Accepted: 03/19/2022] [Indexed: 12/22/2022]
Abstract
Aging is associated with auditory nerve (AN) functional deficits and decreased inhibition in the central auditory system, amplifying central responses in a process referred to here as central gain. Although central gain increases response amplitudes, central gain may not restore disrupted response timing. In this translational study, we measured responses putatively generated by the AN and auditory midbrain in younger and older mice and humans. We hypothesized that older mice and humans exhibit increased central gain without an improvement in inter-trial synchrony in the midbrain. Our data demonstrated greater age-related deficits in AN response amplitudes than auditory midbrain response amplitudes, as shown by significant interactions between inferred neural generator and age group, indicating increased central gain in auditory midbrain. However, synchrony decreases with age in both the AN and midbrain responses. These results reveal age-related increases in central gain without concomitant improvements in synchrony, consistent with those predictions based on decreases in inhibition. Persistent decreases in synchrony may contribute to auditory processing deficits in older mice and humans.
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Affiliation(s)
- Jeffrey A Rumschlag
- Department of Otolaryngology-Head & Neck Surgery, Medical University of South Carolina, Charleston, SC, USA.
| | - Carolyn M McClaskey
- Department of Otolaryngology-Head & Neck Surgery, Medical University of South Carolina, Charleston, SC, USA
| | - James W Dias
- Department of Otolaryngology-Head & Neck Surgery, Medical University of South Carolina, Charleston, SC, USA
| | - Lilyana B Kerouac
- Department of Otolaryngology-Head & Neck Surgery, Medical University of South Carolina, Charleston, SC, USA
| | - Kenyaria V Noble
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA
| | | | - Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Kelly C Harris
- Department of Otolaryngology-Head & Neck Surgery, Medical University of South Carolina, Charleston, SC, USA
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Shehabi AM, Prendergast G, Plack CJ. The Relative and Combined Effects of Noise Exposure and Aging on Auditory Peripheral Neural Deafferentation: A Narrative Review. Front Aging Neurosci 2022; 14:877588. [PMID: 35813954 PMCID: PMC9260498 DOI: 10.3389/fnagi.2022.877588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/30/2022] [Indexed: 11/13/2022] Open
Abstract
Animal studies have shown that noise exposure and aging cause a reduction in the number of synapses between low and medium spontaneous rate auditory nerve fibers and inner hair cells before outer hair cell deterioration. This noise-induced and age-related cochlear synaptopathy (CS) is hypothesized to compromise speech recognition at moderate-to-high suprathreshold levels in humans. This paper evaluates the evidence on the relative and combined effects of noise exposure and aging on CS, in both animals and humans, using histopathological and proxy measures. In animal studies, noise exposure seems to result in a higher proportion of CS (up to 70% synapse loss) compared to aging (up to 48% synapse loss). Following noise exposure, older animals, depending on their species, seem to either exhibit significant or little further synapse loss compared to their younger counterparts. In humans, temporal bone studies suggest a possible age- and noise-related auditory nerve fiber loss. Based on the animal data obtained from different species, we predict that noise exposure may accelerate age-related CS to at least some extent in humans. In animals, noise-induced and age-related CS in separation have been consistently associated with a decreased amplitude of wave 1 of the auditory brainstem response, reduced middle ear muscle reflex strength, and degraded temporal processing as demonstrated by lower amplitudes of the envelope following response. In humans, the individual effects of noise exposure and aging do not seem to translate clearly into deficits in electrophysiological, middle ear muscle reflex, and behavioral measures of CS. Moreover, the evidence on the combined effects of noise exposure and aging on peripheral neural deafferentation in humans using electrophysiological and behavioral measures is even more sparse and inconclusive. Further research is necessary to establish the individual and combined effects of CS in humans using temporal bone, objective, and behavioral measures.
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Affiliation(s)
- Adnan M. Shehabi
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
- Department of Audiology and Speech Therapy, Birzeit University, Birzeit, Palestine
| | - Garreth Prendergast
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
| | - Christopher J. Plack
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
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Le Prell CG. Prevention of Noise-Induced Hearing Loss Using Investigational Medicines for the Inner Ear: Previous Trial Outcomes Should Inform Future Trial Design. Antioxid Redox Signal 2022; 36:1171-1202. [PMID: 34346254 PMCID: PMC9221155 DOI: 10.1089/ars.2021.0166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 07/25/2021] [Indexed: 11/13/2022]
Abstract
Significance: Noise-induced hearing loss (NIHL) is an important public health issue resulting in decreased quality of life for affected individuals, and significant costs to employers and governmental agencies. Recent Advances: Advances in the mechanistic understanding of NIHL have prompted a growing number of proposed, in-progress, and completed clinical trials for possible protections against NIHL via antioxidants and other drug agents. Thirty-one clinical trials evaluating prevention of either temporary or permanent NIHL were identified and are reviewed. Critical Issues: This review revealed little consistency in the noise-exposed populations in which drugs are evaluated or the primary outcomes used to measure NIHL prevention. Changes in pure-tone thresholds were the most common primary outcomes; specific threshold metrics included both average hearing loss and incidence of significant hearing loss. Changes in otoacoustic emission (OAE) amplitude were relatively common secondary outcomes. Extended high-frequency (EHF) hearing and speech-in-noise perception are commonly adversely affected by noise exposure but are not consistently included in clinical trials assessing prevention of NIHL. Future Directions: Multiple criteria are available for monitoring NIHL, but the specific criterion to be used to define clinically significant otoprotection remains a topic of discussion. Audiogram-based primary outcome measures can be combined with secondary outcomes, including OAE amplitude, EHF hearing, speech-in-noise testing, tinnitus surveys, and patient-reported outcomes. Standardization of test protocols for the above primary and secondary outcomes, and associated reporting criterion for each, would facilitate clinical trial design and comparison of results across investigational drug agents. Antioxid. Redox Signal. 36, 1171-1202.
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Affiliation(s)
- Colleen G. Le Prell
- Department of Speech, Language, and Hearing Science, University of Texas at Dallas, Richardson, Texas, USA
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Shehabi AM, Prendergast G, Guest H, Plack CJ. The Effect of Lifetime Noise Exposure and Aging on Speech-Perception-in-Noise Ability and Self-Reported Hearing Symptoms: An Online Study. Front Aging Neurosci 2022; 14:890010. [PMID: 35711902 PMCID: PMC9195834 DOI: 10.3389/fnagi.2022.890010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 04/28/2022] [Indexed: 12/03/2022] Open
Abstract
Animal research shows that aging and excessive noise exposure damage cochlear outer hair cells, inner hair cells, and the synapses connecting inner hair cells with the auditory nerve. This may translate into auditory symptoms such as difficulty understanding speech in noise, tinnitus, and hyperacusis. The current study, using a novel online approach, assessed and quantified the effects of lifetime noise exposure and aging on (i) speech-perception-in-noise (SPiN) thresholds, (ii) self-reported hearing ability, and (iii) the presence of tinnitus. Secondary aims involved documenting the effects of lifetime noise exposure and aging on tinnitus handicap and the severity of hyperacusis. Two hundred and ninety-four adults with no past diagnosis of hearing or memory impairments were recruited online. Participants were assigned into two groups: 217 "young" (age range: 18-35 years, females: 151) and 77 "older" (age range: 50-70 years, females: 50). Participants completed a set of online instruments including an otologic health and demographic questionnaire, a dementia screening tool, forward and backward digit span tests, a noise exposure questionnaire, the Khalfa hyperacusis questionnaire, the short-form of the Speech, Spatial, and Qualities of Hearing scale, the Tinnitus Handicap Inventory, a digits-in-noise test, and a Coordinate Response Measure speech-perception test. Analyses controlled for sex and cognitive function as reflected by the digit span. A detailed protocol was pre-registered, to guard against "p-hacking" of this extensive dataset. Lifetime noise exposure did not predict SPiN thresholds, self-reported hearing ability, or the presence of tinnitus in either age group. Exploratory analyses showed that worse hyperacusis scores, and a greater prevalence of tinnitus, were associated significantly with high lifetime noise exposure in the young, but not in the older group. Age was a significant predictor of SPiN thresholds and the presence of tinnitus, but not of self-reported hearing ability, tinnitus handicap, or severity of hyperacusis. Consistent with several lab studies, our online-derived data suggest that older adults with no diagnosis of hearing impairment have a poorer SPiN ability and a higher risk of tinnitus than their younger counterparts. Moreover, lifetime noise exposure may increase the risk of tinnitus and the severity of hyperacusis in young adults with no diagnosis of hearing impairment.
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Affiliation(s)
- Adnan M. Shehabi
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
- Department of Audiology and Speech Therapy, Birzeit University, Birzeit, Palestine
| | - Garreth Prendergast
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
| | - Hannah Guest
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
| | - Christopher J. Plack
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
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Eggink MC, Frijns JHM, Sagers JE, O'Malley JT, Liberman MC, Stankovic KM. Human vestibular schwannoma reduces density of auditory nerve fibers in the osseous spiral lamina. Hear Res 2022; 418:108458. [PMID: 35334332 PMCID: PMC11181009 DOI: 10.1016/j.heares.2022.108458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 02/05/2022] [Indexed: 12/24/2022]
Abstract
Hearing loss in patients with vestibular schwannoma (VS) is commonly attributed to mechanical compression of the auditory nerve, though recent studies suggest that this retrocochlear pathology may be augmented by cochlear damage. Although VS-associated loss of inner hair cells, outer hair cells, and spiral ganglion cells has been reported, it is unclear to what extent auditory-nerve peripheral axons are damaged in VS patients. Understanding the degree of damage VSs cause to auditory nerve fibers (ANFs) is important for accurately modeling clinical outcomes of cochlear implantation, which is a therapeutic option to rehabilitate hearing in VS-affected ears. A retrospective analysis of human temporal-bone histopathology was performed on archival specimens from the Massachusetts Eye and Ear collection. Seven patients met our inclusion criteria based on the presence of sporadic, unilateral, untreated VS. Tangential sections of five cochlear regions were stained with hematoxylin and eosin, and adjacent sections were stained to visualize myelinated ANFs and efferent fibers. Following confocal microscopy, peripheral axons of ANFs within the osseous spiral lamina were quantified manually, where feasible, and with a "pixel counting" method, applicable to all sections. ANF density was substantially reduced on the VS side compared to the unaffected contralateral side. In the upper basal turn, a significant difference between the VS side and unaffected contralateral side was found using both counting methods, corresponding to the region tuned to 2000 Hz. Even spiral ganglion cells (SGCs) contralateral to VS were affected by the tumor as the majority of contralateral SGC counts were below average for age. This observation provides histological insight into the clinical observation that unilateral vestibular schwannomas pose a long-term risk of progression of hearing loss in the contralateral ear as well. Our pixel counting method for ANF quantification in the osseous spiral lamina is applicable to other pathologies involving sensorineural hearing loss. Future research is needed to classify ANFs into morphological categories, accurately predict their electrical properties, and use this knowledge to inform optimal cochlear implant programming strategies.
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Affiliation(s)
- Maura C Eggink
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA; Department of Otorhinolaryngology, Leiden University Medical Center, Leiden, the Netherlands; Department of Otorhinolaryngology, Amsterdam UMC, location Academic Medical Center, University of Amsterdam, the Netherlands
| | - Johan H M Frijns
- Department of Otorhinolaryngology, Leiden University Medical Center, Leiden, the Netherlands; The Leiden Institute for Brain and Cognition, Leiden, the Netherlands
| | - Jessica E Sagers
- Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA
| | - Jennifer T O'Malley
- Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA
| | - M Charles Liberman
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA
| | - Konstantina M Stankovic
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories and Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA; Department of Otolaryngology, Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA.
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Ding Y, Liang Y, Cao C, Zhang Y, Hu M. Relationships Among Temporal Fine Structure Sensitivity, Transient Storage Capacity, and Ultra-High Frequency Hearing Thresholds in Tinnitus Patients and Normal Adults of Different Ages. Front Aging Neurosci 2022; 14:869708. [PMID: 35557835 PMCID: PMC9087330 DOI: 10.3389/fnagi.2022.869708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/05/2022] [Indexed: 11/22/2022] Open
Abstract
Background Elderlies and tinnitus patients often find it challenging to process acoustic signals in noisy environments. The sensitivity to temporal fine structure (TFS), the transient storage capacity for TFS, and the ultra-high frequency (UHF) thresholds are all associated with aging-related damage, evidenced by speech-in-noise perception deficits. In the present study, we aimed to investigate the relationships among TFS sensitivity, transient storage capacity, and UHF thresholds in tinnitus patients and normal adults of different ages. Methods In the present study, 38 tinnitus patients (age ranging from 21 to 65) and 23 non-tinnitus adults (age ranging from 22 to 56) were enrolled, and some of their auditory indicators were examined, including the TFS-adaptive frequency (TFS-AF), break in interaural correlation (BIAC) delay threshold, and UHF thresholds. Results We found no significant difference in TFS-AF thresholds and BIAC delay thresholds between the tinnitus group and normal group, while their relationships with age were more evident in the tinnitus group. Moreover, these two tests were only significantly correlated in the tinnitus group. UHF thresholds were significantly correlated with TFS-AF thresholds only in the tinnitus group, suggesting that the UHF hearing was positively associated with the TFS sensitivity. Conclusion These findings indicated that the influencing factors, such as tinnitus and UHF thresholds, should be fully considered when examining age-related hearing decline, because the combination of tinnitus and poor UHF hearing might play a role in affecting hearing ability, such as TFS sensitivity.
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Affiliation(s)
- Yu Ding
- Division of Sports Science and Physical Education, Tsinghua University, Beijing, China
| | - Yibo Liang
- Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Tianjin, China
- Institute of Otolaryngology of Tianjin, Tianjin, China
- Key Laboratory of Auditory Speech and Balance Medicine, Tianjin, China
- Key Clinical Discipline of Tianjin (Otolaryngology), Tianjin, China
- Otolaryngology Clinical Quality Control Centre, Tianjin, China
| | - Chunmei Cao
- Division of Sports Science and Physical Education, Tsinghua University, Beijing, China
| | - Yueqi Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Tianjin, China
- Institute of Otolaryngology of Tianjin, Tianjin, China
- Key Laboratory of Auditory Speech and Balance Medicine, Tianjin, China
- Key Clinical Discipline of Tianjin (Otolaryngology), Tianjin, China
- Otolaryngology Clinical Quality Control Centre, Tianjin, China
| | - Ming Hu
- Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Tianjin, China
- Institute of Otolaryngology of Tianjin, Tianjin, China
- Key Laboratory of Auditory Speech and Balance Medicine, Tianjin, China
- Key Clinical Discipline of Tianjin (Otolaryngology), Tianjin, China
- Otolaryngology Clinical Quality Control Centre, Tianjin, China
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50
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Seicol BJ, Lin S, Xie R. Age-Related Hearing Loss Is Accompanied by Chronic Inflammation in the Cochlea and the Cochlear Nucleus. Front Aging Neurosci 2022; 14:846804. [PMID: 35418849 PMCID: PMC8995794 DOI: 10.3389/fnagi.2022.846804] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 03/07/2022] [Indexed: 12/24/2022] Open
Abstract
Age-related hearing loss (ARHL) is a major hearing impairment characterized by pathological changes in both the peripheral and central auditory systems. Low-grade inflammation was observed in the cochlea of deceased human subjects with ARHL and animal models of early onset ARHL, which suggests that inflammation contributes to the development of ARHL. However, it remains elusive how chronic inflammation progresses during normal aging in the cochlea, and especially the accompanying changes of neuroinflammation in the central auditory system. To address this, we investigated chronic inflammation in both the cochlea and the cochlear nucleus (CN) of CBA/CaJ mice, an inbred mouse strain that undergoes normal aging and develops human, like-late-onset ARHL. Using immunohistochemistry, confocal microscopy, and quantitative image processing, we measured the accumulation and activation of macrophages in the cochlea and microglia in the CN using their shared markers: ionized calcium binding adaptor molecule 1 (Iba1) and CD68-a marker of phagocytic activity. We found progressive increases in the area covered by Iba1-labeled macrophages and enhanced CD68 staining in the osseous spiral lamina of the cochlea that correlated with elevated ABR threshold across the lifespan. During the process, we further identified significant increases in microglial activation and C1q deposition in the CN, indicating increased neuroinflammation and complement activation in the central auditory system. Our study suggests that during normal aging, chronic inflammation occurs in both the peripheral and the central auditory system, which may contribute in coordination to the development of ARHL.
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Affiliation(s)
- Benjamin J. Seicol
- Department of Otolaryngology—Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
- Department of Neuroscience, The Ohio State University, Columbus, OH, United States
| | - Shengyin Lin
- Department of Otolaryngology—Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
| | - Ruili Xie
- Department of Otolaryngology—Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
- Department of Neuroscience, The Ohio State University, Columbus, OH, United States
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