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Svobodová V, Profant O, Syka J, Tóthová D, Bureš Z. The Influence of Asymmetric Hearing Loss on Peripheral and Central Auditory Processing Abilities in Patients With Vestibular Schwannoma. Ear Hear 2024:00003446-990000000-00311. [PMID: 39004787 DOI: 10.1097/aud.0000000000001555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
OBJECTIVES Asymmetric or unilateral hearing loss (AHL) may cause irreversible changes in the processing of acoustic signals in the auditory system. We aim to provide a comprehensive view of the auditory processing abilities for subjects with acquired AHL, and to examine the influence of AHL on speech perception under difficult conditions, and on auditory temporal and intensity processing. DESIGN We examined peripheral and central auditory functions for 25 subjects with AHL resulting from vestibular schwannoma, and compared them to those from 24 normal-hearing controls that were matched with the AHL subjects in mean age and hearing thresholds in the healthy ear. Besides the basic hearing threshold assessment, the tests comprised the detection of tones and gaps in a continuous noise, comprehension of speech in babble noise, binaural interactions, difference limen of intensity, and detection of frequency modulation. For the AHL subjects, the selected tests were performed separately for the healthy and diseased ear. RESULTS We observed that binaural speech comprehension, gap detection, and frequency modulation detection abilities were dominated by the healthy ear and were comparable for both groups. The AHL subjects were less sensitive to interaural delays, however, they exhibited a higher sensitivity to sound level, as indicated by lower difference limen of intensity and a higher sensitivity to interaural intensity difference. Correlations between the individual test scores indicated that speech comprehension by the AHL subjects was associated with different auditory processing mechanisms than for the control subjects. CONCLUSIONS The data suggest that AHL influences both peripheral and central auditory processing abilities and that speech comprehension under difficult conditions relies on different mechanisms for the AHL subjects than for normal-hearing controls.
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Affiliation(s)
- Veronika Svobodová
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Prague 4, Czech Republic
- Department of Otorhinolaryngology and Head and Neck Surgery, First Faculty of Medicine, University Hospital Motol, Charles University in Prague, Prague 5, Czech Republic
| | - Oliver Profant
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Prague 4, Czech Republic
- Department of Otorhinolaryngology, Third Faculty of Medicine, University Hospital Královské Vinohrady, Charles University in Prague, Prague 10, Czech Republic
| | - Josef Syka
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Prague 4, Czech Republic
- Department of Cognitive Systems and Neurosciences, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Prague 6, Czech Republic
| | - Diana Tóthová
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Prague 4, Czech Republic
- Department of Otorhinolaryngology and Head and Neck Surgery, First Faculty of Medicine, University Hospital Motol, Charles University in Prague, Prague 5, Czech Republic
| | - Zbyněk Bureš
- Department of Otorhinolaryngology, Third Faculty of Medicine, University Hospital Královské Vinohrady, Charles University in Prague, Prague 10, Czech Republic
- Department of Technical Studies, College of Polytechnics Jihlava, Jihlava, Czech Republic
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Patro C, Monfiletto A, Singer A, Srinivasan NK, Mishra SK. Midlife Speech Perception Deficits: Impact of Extended High-Frequency Hearing, Peripheral Neural Function, and Cognitive Abilities. Ear Hear 2024:00003446-990000000-00269. [PMID: 38556645 DOI: 10.1097/aud.0000000000001504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
OBJECTIVES The objectives of the present study were to investigate the effects of age-related changes in extended high-frequency (EHF) hearing, peripheral neural function, working memory, and executive function on speech perception deficits in middle-aged individuals with clinically normal hearing. DESIGN We administered a comprehensive assessment battery to 37 participants spanning the age range of 20 to 56 years. This battery encompassed various evaluations, including standard and EHF pure-tone audiometry, ranging from 0.25 to 16 kHz. In addition, we conducted auditory brainstem response assessments with varying stimulation rates and levels, a spatial release from masking (SRM) task, and cognitive evaluations that involved the Trail Making test (TMT) for assessing executive function and the Abbreviated Reading Span test (ARST) for measuring working memory. RESULTS The results indicated a decline in hearing sensitivities at EHFs and an increase in completion times for the TMT with age. In addition, as age increased, there was a corresponding decrease in the amount of SRM. The declines in SRM were associated with age-related declines in hearing sensitivity at EHFs and TMT performance. While we observed an age-related decline in wave I responses, this decline was primarily driven by age-related reductions in EHF thresholds. In addition, the results obtained using the ARST did not show an age-related decline. Neither the auditory brainstem response results nor ARST scores were correlated with the amount of SRM. CONCLUSIONS These findings suggest that speech perception deficits in middle age are primarily linked to declines in EHF hearing and executive function, rather than cochlear synaptopathy or working memory.
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Affiliation(s)
- Chhayakanta Patro
- Department of Speech Language Pathology & Audiology, Towson University, Towson, Maryland, USA
| | - Angela Monfiletto
- Department of Speech Language Pathology & Audiology, Towson University, Towson, Maryland, USA
| | - Aviya Singer
- Department of Speech Language Pathology & Audiology, Towson University, Towson, Maryland, USA
| | - Nirmal Kumar Srinivasan
- Department of Speech Language Pathology & Audiology, Towson University, Towson, Maryland, USA
| | - Srikanta Kumar Mishra
- Department of Speech, Language and Hearing Sciences, The University of Texas at Austin, Austin, Texas, USA
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Bovee S, Klump GM, Pyott SJ, Sielaff C, Köppl C. Cochlear Ribbon Synapses in Aged Gerbils. Int J Mol Sci 2024; 25:2738. [PMID: 38473985 DOI: 10.3390/ijms25052738] [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: 12/30/2023] [Revised: 02/15/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
In mammalian hearing, type-I afferent auditory nerve fibers comprise the basis of the afferent auditory pathway. They are connected to inner hair cells of the cochlea via specialized ribbon synapses. Auditory nerve fibers of different physiological types differ subtly in their synaptic location and morphology. Low-spontaneous-rate auditory nerve fibers typically connect on the modiolar side of the inner hair cell, while high-spontaneous-rate fibers are typically found on the pillar side. In aging and noise-damaged ears, this fine-tuned balance between auditory nerve fiber populations can be disrupted and the functional consequences are currently unclear. Here, using immunofluorescent labeling of presynaptic ribbons and postsynaptic glutamate receptor patches, we investigated changes in synaptic morphology at three different tonotopic locations along the cochlea of aging gerbils compared to those of young adults. Quiet-aged gerbils showed about 20% loss of afferent ribbon synapses. While the loss was random at apical, low-frequency cochlear locations, at the basal, high-frequency location it almost exclusively affected the modiolar-located synapses. The subtle differences in volumes of pre- and postsynaptic elements located on the inner hair cell's modiolar versus pillar side were unaffected by age. This is consistent with known physiology and suggests a predominant, age-related loss in the low-spontaneous-rate auditory nerve population in the cochlear base, but not the apex.
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Affiliation(s)
- Sonny Bovee
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| | - Georg M Klump
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Cluster of Excellence "Hearing4all", Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| | - Sonja J Pyott
- Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
| | - Charlotte Sielaff
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), 30625 Hannover, Germany
| | - Christine Köppl
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Cluster of Excellence "Hearing4all", Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
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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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Bramhall NF, McMillan GP. Perceptual Consequences of Cochlear Deafferentation in Humans. Trends Hear 2024; 28:23312165241239541. [PMID: 38738337 DOI: 10.1177/23312165241239541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024] Open
Abstract
Cochlear synaptopathy, a form of cochlear deafferentation, has been demonstrated in a number of animal species, including non-human primates. Both age and noise exposure contribute to synaptopathy in animal models, indicating that it may be a common type of auditory dysfunction in humans. Temporal bone and auditory physiological data suggest that age and occupational/military noise exposure also lead to synaptopathy in humans. The predicted perceptual consequences of synaptopathy include tinnitus, hyperacusis, and difficulty with speech-in-noise perception. However, confirming the perceptual impacts of this form of cochlear deafferentation presents a particular challenge because synaptopathy can only be confirmed through post-mortem temporal bone analysis and auditory perception is difficult to evaluate in animals. Animal data suggest that deafferentation leads to increased central gain, signs of tinnitus and abnormal loudness perception, and deficits in temporal processing and signal-in-noise detection. If equivalent changes occur in humans following deafferentation, this would be expected to increase the likelihood of developing tinnitus, hyperacusis, and difficulty with speech-in-noise perception. Physiological data from humans is consistent with the hypothesis that deafferentation is associated with increased central gain and a greater likelihood of tinnitus perception, while human data on the relationship between deafferentation and hyperacusis is extremely limited. Many human studies have investigated the relationship between physiological correlates of deafferentation and difficulty with speech-in-noise perception, with mixed findings. A non-linear relationship between deafferentation and speech perception may have contributed to the mixed results. When differences in sample characteristics and study measurements are considered, the findings may be more consistent.
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Affiliation(s)
- Naomi F Bramhall
- VA National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, Portland, OR, USA
- Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, OR, USA
| | - Garnett P McMillan
- VA National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, Portland, OR, USA
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