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Bader K, Dalhoff E, Dierkes L, Braun LH, Gummer AW, Zelle D. Reliable Long-Term Serial Evaluation of Cochlear Function Using Pulsed Distortion-Product Otoacoustic Emissions: Analyzing Levels and Pressure Time Courses. Ear Hear 2024:00003446-990000000-00284. [PMID: 38809242 DOI: 10.1097/aud.0000000000001522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
OBJECTIVES To date, there is no international standard on how to use distortion-product otoacoustic emissions (DPOAEs) in serial measurements to accurately detect changes in the function of the cochlear amplifier due, for example, to ototoxic therapies, occupational noise, or the development of regenerative therapies. The use of clinically established standard DPOAE protocols for serial monitoring programs appears to be hampered by multiple factors, including probe placement and calibration effects, signal-processing complexities associated with multiple sites of emission generation as well as suboptimal selection of stimulus parameters. DESIGN Pulsed DPOAEs were measured seven times within 3 months for f2 = 1 to 14 kHz and L2 = 25 to 80 dB SPL in 20 ears of 10 healthy participants with normal hearing (mean age = 32.1 ± 9.7 years). L1 values were computed from individual optimal-path parameters derived from the corresponding individual DPOAE level map in the first test session. Three different DPOAE metrics for evaluating the functional state of the cochlear amplifier were investigated with respect to their test-retest reliability: (1) the interference-free, nonlinear-distortion component level (LOD), (2) the time course of the DPOAE-envelope levels, LDP(t), and (3) the squared, zero-lag correlation coefficient () between the time courses of the DPOAE-envelope pressures, pDP(t), measured in two sessions. The latter two metrics include the two main DPOAE components and their state of interference. RESULTS Collated over all sessions and frequencies, the median absolute difference for LOD was 1.93 dB and for LDP(t) was 2.52 dB; the median of was 0.988. For the low (f2 = 1 to 3 kHz), mid (f2 = 4 to 9 kHz), and high (f2 = 10 to 14 kHz) frequency ranges, the test-retest reliability of LOD increased with increasing signal to noise ratio (SNR). CONCLUSIONS On the basis of the knowledge gained from this study on the test-retest reliability of pulsed DPOAE signals and the current literature, we propose a DPOAE protocol for future serial monitoring applications that takes into account the following factors: (1) separation of DPOAE components, (2) use of individually optimal stimulus parameters, (3) SNR of at least 15 dB, (4) accurate pressure calibration, (5) consideration of frequency- and level-dependent test-retest reliabilities and corresponding reference ranges, and (6) stimulus levels L2 that are as low as possible with sufficient SNR to capture the nonlinear functional state of the cochlear amplifier operating at its highest gain.
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Affiliation(s)
- Katharina Bader
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Linda Dierkes
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Tübingen, Germany
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Lore Helene Braun
- Department of Radiooncology, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Tübingen, Germany
- Earlab GmbH, Tübingen, Germany
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2
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Bader K, Zelle D, Gummer AW, Dalhoff E. [Pulsed DPOAEs in serial measurements : Combined analysis paradigm of simultaneously occurring changes in hearing thresholds and DPOAEs. German version]. HNO 2024:10.1007/s00106-024-01477-0. [PMID: 38801424 DOI: 10.1007/s00106-024-01477-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/29/2024] [Indexed: 05/29/2024]
Abstract
BACKGROUND To date, there is no consensus on how to standardize the assessment of ototoxicity in serial measurements. For the diagnosis of damage to the cochlear amplifier, measurement methods are required that have the highest possible test-retest reliability and validity for detecting persistent damage. Estimated distortion-product thresholds (LEDPT) based on short-pulse distortion-product otoacoustic emission (DPOAE) level maps use individually optimal DPOAE stimulus levels and allow reliable quantitative estimation of cochlea-related hearing loss. MATERIALS AND METHODS Hearing thresholds were estimated objectively using LEDPT and subjectively using modified Békésy tracking audiometry (LTA). Recordings were performed seven times within three months at 14 frequencies (f2 = 1-14 kHz) in 20 ears (PTA4 (0.5-4 kHz) < 20 dB HL). Reconstruction of the DPOAE growth behavior as a function of the stimulus levels L1, L2 was performed on the basis of 21 DPOAE amplitudes. A numerical fit of a nonlinear mathematical function to the three-dimensional DPOAE growth function yielded LEDPT for each stimulus frequency. For the combined analysis, probability distributions of hearing thresholds (LTA, LEDPT), DPOAE levels (LDP), and combinations thereof were determined. RESULTS LTA and LEDPT each exhibited a test-retest reliability with a median of absolute differences (AD) of 3.2 dB and 3.3 dB, respectively. Combining LEDPT, LDP, and LTA into a single parameter yielded a significantly smaller median AD of 2.0 dB. CONCLUSION It is expected that an analysis paradigm based on a combination of LEDPT, suprathreshold LDP, and fine-structure-reduced LTA would achieve higher test performance (sensitivity and specificity), allowing reliable detection of pathological or regenerative changes in the outer hair cells.
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Affiliation(s)
- Katharina Bader
- Klinik für Hals-Nasen-Ohren-Heilkunde, Universitätsklinikum Tübingen, Elfriede-Aulhorn-Straße 5, 72076, Tübingen, Deutschland.
- Sektion für Physiologische Akustik und Kommunikation, Universitäts-HNO-Klinik Tübingen, Tübingen, Deutschland.
| | - Dennis Zelle
- Sektion für Physiologische Akustik und Kommunikation, Universitäts-HNO-Klinik Tübingen, Tübingen, Deutschland
- Earlab GmbH, Tübingen, Deutschland
| | - Anthony W Gummer
- Sektion für Physiologische Akustik und Kommunikation, Universitäts-HNO-Klinik Tübingen, Tübingen, Deutschland
| | - Ernst Dalhoff
- Sektion für Physiologische Akustik und Kommunikation, Universitäts-HNO-Klinik Tübingen, Tübingen, Deutschland
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Moleti A. Optimal Scale-Invariant Wavelet Representation and Filtering of Human Otoacoustic Emissions. J Assoc Res Otolaryngol 2024:10.1007/s10162-024-00943-4. [PMID: 38789824 DOI: 10.1007/s10162-024-00943-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 03/04/2024] [Indexed: 05/26/2024] Open
Abstract
Otoacoustic emissions (OAEs) are generated in the cochlea and recorded in the ear canal either as a time domain waveform or as a collection of complex responses to tones in the frequency domain (Probst et al. J Account Soc Am 89:2027-2067, 1991). They are typically represented either in their original acquisition domain or in its Fourier-conjugated domain. Round-trip excursions to the conjugated domain are often used to perform filtering operations in the computationally simplest way, exploiting the convolution theorem. OAE signals consist of the superposition of backward waves generated in different cochlear regions by different generation mechanisms, over a wide frequency range. The cochlear scaling symmetry (cochlear physics is the same at all frequency scales), which approximately holds in the human cochlea, leaves its fingerprints in the mathematical properties of OAE signals. According to a generally accepted taxonomy (Sher and Guinan Jr, J Acoust Soc Am 105:782-798, 1999), OAEs are generated either by wave-fixed sources, moving with frequency according with the cochlear scaling (as in nonlinear distortion) or by place-fixed sources (as in coherent reflection by roughness). If scaling symmetry holds, the two generation mechanisms yield OAEs with different phase gradient delay: almost null for wave-fixed sources, and long (and scaling as 1/f) for place-fixed sources. Thus, the most effective representation of OAE signals is often that respecting the cochlear scale-invariance, such as the time-frequency domain representation provided by the wavelet transform. In the time-frequency domain, the elaborate spectra or waveforms yielded by the superposition of OAE components from different generation mechanisms assume a much clearer 2-D pattern, with each component localized in a specific and predictable region. The wavelet representation of OAE signals is optimal both for visualization purposes and for designing filters that effectively separate different OAE components, improving both the specificity and the sensitivity of OAE-based applications. Indeed, different OAE components have different physiological meanings, and filtering dramatically improves the signal-to-noise ratio.
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Affiliation(s)
- Arturo Moleti
- Department of Physics and NAST Centre - University of Rome 'Tor Vergata', Rome, Italy.
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4
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Dewey JB, Shera CA. Similar Tuning of Distortion-Product Otoacoustic Emission Ratio Functions and Cochlear Vibrations in Mice. AIP CONFERENCE PROCEEDINGS 2024; 3062:060005. [PMID: 38516507 PMCID: PMC10956552 DOI: 10.1063/5.0195534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
When elicited by two stimulus tones (at frequencies f1 and f2, f2 > f1), the amplitudes of specific distortion-product otoacoustic emission (DPOAE) components exhibit a characteristic bandpass shape as the ratio between f2 and f1 is varied. This bandpass shape has been attributed to various mechanisms including intracochlear resonance, suppression, and wave interference, and has been proposed to be related to cochlear frequency tuning. While human studies suggest modest correlations between psychophysical tuning and the tuning of DPOAE amplitude vs. f2/f1 ratio functions, a relationship between the latter and the tuning of cochlear mechanical responses has yet to be established. This was addressed here through direct comparisons of DPOAEs and cochlear vibrations in wild-type CBA/CaJ mice. DPOAEs were elicited using a fixed-f2, swept-f1 paradigm, and optical coherence tomography was used to measure displacements from cochlear locations with characteristic frequencies near f2. The tuning sharpness of 2f1-f2 DPOAE ratio functions was found to be remarkably similar to that of basilar membrane and/or tectorial membrane responses to single tones, with the tuning sharpness of all responses increasing similarly with decreasing stimulus level. This relationship was observed for f2 frequencies ranging from ~8 to 22 kHz. Intracochlear distortion products did not exhibit a bandpass shape as the f2/f1 ratio was varied, indicating that interference between distortion products traveling to the stapes may be responsible for the tuning of the DPOAE ratio function. While these findings suggest that DPOAE ratio functions could be used to noninvasively infer cochlear tuning, it remains to be determined whether this relationship holds in other species and for lower frequency regions.
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Affiliation(s)
- James B. Dewey
- Caruso Department of Otolaryngology – Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
| | - Christopher A. Shera
- Caruso Department of Otolaryngology – Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA
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Guthrie OW. Noise Stress Abrogates Structure-Specific Endonucleases within the Mammalian Inner Ear. Int J Mol Sci 2024; 25:1749. [PMID: 38339024 PMCID: PMC10855171 DOI: 10.3390/ijms25031749] [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: 11/30/2023] [Revised: 01/19/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
Nucleotide excision repair (NER) is a multistep biochemical process that maintains the integrity of the genome. Unlike other mechanisms that maintain genomic integrity, NER is distinguished by two irreversible nucleolytic events that are executed by the xeroderma pigmentosum group G (XPG) and xeroderma pigmentosum group F (XPF) structure-specific endonucleases. Beyond nucleolysis, XPG and XPF regulate the overall efficiency of NER through various protein-protein interactions. The current experiments evaluated whether an environmental stressor could negatively affect the expression of Xpg (Ercc5: excision repair cross-complementing 5) or Xpf (Ercc4: excision repair cross-complementing 4) in the mammalian cochlea. Ubiquitous background noise was used as an environmental stressor. Gene expression levels for Xpg and Xpf were quantified from the cochlear neurosensory epithelium after noise exposure. Further, nonlinear cochlear signal processing was investigated as a functional consequence of changes in endonuclease expression levels. Exposure to stressful background noise abrogated the expression of both Xpg and Xpf, and these effects were associated with pathological nonlinear signal processing from receptor cells within the mammalian inner ear. Given that exposure to environmental sounds (noise, music, etc.) is ubiquitous in daily life, sound-induced limitations to structure-specific endonucleases might represent an overlooked genomic threat.
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Affiliation(s)
- O'neil W Guthrie
- Cell & Molecular Pathology Laboratory, Department of Communication Sciences and Disorders, Northern Arizona University, Flagstaff, AZ 86011, USA
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6
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Moleti A, Minniti T, Viziano A, Stefani A, Cerroni R, Garasto E, Pierantozzi M, Sisto R. Enhanced suppression of otoacoustic emissions by contralateral stimulation in Parkinson's disease. JASA EXPRESS LETTERS 2023; 3:104401. [PMID: 37787697 DOI: 10.1121/10.0021187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/11/2023] [Indexed: 10/04/2023]
Abstract
Dopamine depletion affects several aspects of hearing function. Previous work [Wu, Yi, Manca, Javaid, Lauer, and Glowatzki, eLife 9, e52419 (2020)] demonstrated the role of dopamine in reducing the firing rates of inner ear cells, which is thought to decrease synaptic excitotoxicity. Thus, a lack of dopamine could indirectly increase acoustic stimulation of medial olivocochlear efferents. To investigate that, here we studied contralateral suppression of distortion product otoacoustic emissions in a population of Parkinsonian patients, compared to an age-matched control group, both audiometrically tested. To rule out activation of the acoustic reflex, middle ear impedance was monitored during testing. The results show significantly stronger contralateral suppression in the patient group.
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Affiliation(s)
- Arturo Moleti
- Department of Physics, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Triestino Minniti
- Department of Physics, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Andrea Viziano
- Department of Clinical Sciences and Translational Medicine, University of Rome "Tor Vergata," 00133 Rome, Italy
- Department of Systems Medicine, Parkinson's Disease Center, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Alessandro Stefani
- Department of Systems Medicine, Parkinson's Disease Center, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Rocco Cerroni
- Department of Systems Medicine, Parkinson's Disease Center, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Elena Garasto
- Department of Systems Medicine, Parkinson's Disease Center, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Mariangela Pierantozzi
- Department of Systems Medicine, Parkinson's Disease Center, University of Rome "Tor Vergata," 00133 Rome, Italy
| | - Renata Sisto
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Istituto Nazionale per l'Assicurazione Contro gli Infortuni sul Lavoro, 00078 Monte Porzio Catone, Rome, , , , , , , ,
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Sodero AO, Castagna VC, Elorza SD, Gonzalez-Rodulfo SM, Paulazo MA, Ballestero JA, Martin MG, Gomez-Casati ME. Phytosterols reverse antiretroviral-induced hearing loss, with potential implications for cochlear aging. PLoS Biol 2023; 21:e3002257. [PMID: 37619212 PMCID: PMC10449472 DOI: 10.1371/journal.pbio.3002257] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 07/18/2023] [Indexed: 08/26/2023] Open
Abstract
Cholesterol contributes to neuronal membrane integrity, supports membrane protein clustering and function, and facilitates proper signal transduction. Extensive evidence has shown that cholesterol imbalances in the central nervous system occur in aging and in the development of neurodegenerative diseases. In this work, we characterize cholesterol homeostasis in the inner ear of young and aged mice as a new unexplored possibility for the prevention and treatment of hearing loss. Our results show that cholesterol levels in the inner ear are reduced during aging, an effect that is associated with an increased expression of the cholesterol 24-hydroxylase (CYP46A1), the main enzyme responsible for cholesterol turnover in the brain. In addition, we show that pharmacological activation of CYP46A1 with the antiretroviral drug efavirenz reduces the cholesterol content in outer hair cells (OHCs), leading to a decrease in prestin immunolabeling and resulting in an increase in the distortion product otoacoustic emissions (DPOAEs) thresholds. Moreover, dietary supplementation with phytosterols, plant sterols with structure and function similar to cholesterol, was able to rescue the effect of efavirenz administration on the auditory function. Altogether, our findings point towards the importance of cholesterol homeostasis in the inner ear as an innovative therapeutic strategy in preventing and/or delaying hearing loss.
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Affiliation(s)
- Alejandro O. Sodero
- Instituto de Investigaciones Biomédicas, Pontificia Universidad Católica Argentina, Consejo Nacional de Investigaciones Científicas y Técnicas (BIOMED, UCA-CONICET), Buenos Aires, Argentina
| | - Valeria C. Castagna
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas (INGEBI-CONICET), Buenos Aires, Argentina
| | - Setiembre D. Elorza
- Laboratorio de Neurobiología, Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra, Consejo Nacional de Investigaciones Científicas y Técnicas (INIMEC-CONICET-UNC), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Sara M. Gonzalez-Rodulfo
- Instituto de Investigaciones Biomédicas, Pontificia Universidad Católica Argentina, Consejo Nacional de Investigaciones Científicas y Técnicas (BIOMED, UCA-CONICET), Buenos Aires, Argentina
| | - María A. Paulazo
- Instituto de Investigaciones Biomédicas, Pontificia Universidad Católica Argentina, Consejo Nacional de Investigaciones Científicas y Técnicas (BIOMED, UCA-CONICET), Buenos Aires, Argentina
| | - Jimena A. Ballestero
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Mauricio G. Martin
- Laboratorio de Neurobiología, Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra, Consejo Nacional de Investigaciones Científicas y Técnicas (INIMEC-CONICET-UNC), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María Eugenia Gomez-Casati
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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8
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Dewey JB, Shera CA. Bandpass Shape of Distortion-Product Otoacoustic Emission Ratio Functions Reflects Cochlear Frequency Tuning in Normal-Hearing Mice. J Assoc Res Otolaryngol 2023:10.1007/s10162-023-00892-4. [PMID: 37072566 DOI: 10.1007/s10162-023-00892-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 02/02/2023] [Indexed: 04/20/2023] Open
Abstract
The frequency selectivity of the mammalian auditory system is critical for discriminating complex sounds like speech. This selectivity derives from the sharp tuning of the cochlea's mechanical response to sound, which is largely attributed to the amplification of cochlear vibrations by outer hair cells (OHCs). Due to its nonlinearity, the amplification process also leads to the generation of distortion products (DPs), some of which propagate out to the ear canal as DP otoacoustic emissions (DPOAEs). However, the insight that these signals provide about the tuned micro- and macro-mechanics underlying their generation remains unclear. Using optical coherence tomography to measure cochlear vibrations in mice, we show that the cochlea's frequency tuning is reflected in the bandpass shape that is observed in DPOAE amplitudes when the ratio of the two evoking stimulus frequencies is varied (here termed DPOAE "ratio functions"). The tuning sharpness of DPOAE ratio functions and cochlear vibrations co-varied with stimulus level, with a similar quantitative agreement in tuning sharpness observed for both apical and mid-cochlear locations. Measurement of intracochlear DPs revealed that the tuning of the DPOAE ratio functions was not caused by mechanisms that shape DPs locally near where they are generated. Instead, simple model simulations indicate that the bandpass shape is due to a more global wave interference phenomenon. It appears that the filtering of DPOAEs by wave interactions over an extended spatial region allows them to provide a window onto the frequency tuning of single cochlear locations.
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Affiliation(s)
- James B Dewey
- Caruso Department of Otolaryngology - Head and Neck Surgery, University of Southern California, Los Angeles, 90033, CA, USA.
| | - Christopher A Shera
- Caruso Department of Otolaryngology - Head and Neck Surgery, University of Southern California, Los Angeles, 90033, CA, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, 90089, USA
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Paciello F, Ripoli C, Fetoni AR, Grassi C. Redox Imbalance as a Common Pathogenic Factor Linking Hearing Loss and Cognitive Decline. Antioxidants (Basel) 2023; 12:antiox12020332. [PMID: 36829891 PMCID: PMC9952092 DOI: 10.3390/antiox12020332] [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: 12/05/2022] [Revised: 01/23/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023] Open
Abstract
Experimental and clinical data suggest a tight link between hearing and cognitive functions under both physiological and pathological conditions. Indeed, hearing perception requires high-level cognitive processes, and its alterations have been considered a risk factor for cognitive decline. Thus, identifying common pathogenic determinants of hearing loss and neurodegenerative disease is challenging. Here, we focused on redox status imbalance as a possible common pathological mechanism linking hearing and cognitive dysfunctions. Oxidative stress plays a critical role in cochlear damage occurring during aging, as well as in that induced by exogenous factors, including noise. At the same time, increased oxidative stress in medio-temporal brain regions, including the hippocampus, is a hallmark of neurodegenerative disorders like Alzheimer's disease. As such, antioxidant therapy seems to be a promising approach to prevent and/or counteract both sensory and cognitive neurodegeneration. Here, we review experimental evidence suggesting that redox imbalance is a key pathogenetic factor underlying the association between sensorineural hearing loss and neurodegenerative diseases. A greater understanding of the pathophysiological mechanisms shared by these two diseased conditions will hopefully provide relevant information to develop innovative and effective therapeutic strategies.
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Affiliation(s)
- Fabiola Paciello
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Cristian Ripoli
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
- Correspondence: ; Tel.: +39-0630154966
| | - Anna Rita Fetoni
- Unit of Audiology, Department of Neuroscience, Università degli Studi di Napoli Federico II, 80138 Naples, Italy
| | - Claudio Grassi
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
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10
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Dewey JB. Cubic and quadratic distortion products in vibrations of the mouse cochlear apex. JASA EXPRESS LETTERS 2022; 2:114402. [PMID: 36456371 PMCID: PMC9704500 DOI: 10.1121/10.0015244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/03/2022] [Indexed: 06/17/2023]
Abstract
When the ear is stimulated by two tones presented at frequencies f1 and f2, nonlinearity in the cochlea's vibratory response leads to the generation of distortion products (DPs), with the cubic 2f1-f2 DP commonly viewed as the most prominent. While the quadratic f2-f1 DP is also evident in numerous physiological and perceptual studies, its presence in the cochlea's mechanical response has been less well documented. Here, examination of vibratory DPs within the mouse cochlea confirmed that f2-f1 was a significant and sometimes dominant component, whether DPs were measured near their generation site, or after having propagated from more basal locations.
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Affiliation(s)
- James B Dewey
- Caruso Department of Otolaryngology-Head & Neck Surgery, University of Southern California, Los Angeles, California 90033, USA
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Affortit C, Blanc F, Nasr J, Ceccato JC, Markossian S, Guyot R, Puel JL, Flamant F, Wang J. A disease-associated mutation in thyroid hormone receptor α1 causes hearing loss and sensory hair cell patterning defects in mice. Sci Signal 2022; 15:eabj4583. [PMID: 35700264 DOI: 10.1126/scisignal.abj4583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Resistance to thyroid hormone due to mutations in THRA, which encodes the thyroid hormone receptor α (TRα1), shows variable clinical presentation. Mutations affecting TRβ1 and TRβ2 cause deafness in mice and have been associated with deafness in humans. To test whether TRα1 also affects hearing function, we used mice heterozygous for a frameshift mutation in Thra that is similar to human THRA mutations (ThraS1/+ mice) and reduces tissue sensitivity to thyroid hormone. Compared to wild-type littermates, ThraS1/+ mice showed moderate high-frequency sensorineural hearing loss as juveniles and increased age-related hearing loss. Ultrastructural examination revealed aberrant orientation of ~20% of sensory outer hair cells (OHCs), as well as increased numbers of mitochondria with fragmented morphology and autophagic vacuoles in both OHCs and auditory nerve fibers. Molecular dissection of the OHC lateral wall components revealed that the potassium ion channel Kcnq4 was aberrantly targeted to the cytoplasm of mutant OHCs. In addition, mutant cochleae showed increased oxidative stress, autophagy, and mitophagy associated with greater age-related cochlear cell damage, demonstrating that TRα1 is required for proper development of OHCs and for maintenance of OHC function. These findings suggest that patients with THRA mutations may present underdiagnosed, mild hearing loss and may be more susceptible to age-related hearing loss.
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Affiliation(s)
- Corentin Affortit
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Fabian Blanc
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France.,Department of ENT and Head and Neck Surgery, University Hospital of Montpellier, Montpellier, France
| | - Jamal Nasr
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Jean-Charles Ceccato
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Suzy Markossian
- Institut de Génomique Fonctionnelle de Lyon (IGFL), INRAE USC1370, CNRS (UMR5242), ENS, Lyon, France
| | - Romain Guyot
- Institut de Génomique Fonctionnelle de Lyon (IGFL), INRAE USC1370, CNRS (UMR5242), ENS, Lyon, France
| | - Jean-Luc Puel
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Frédéric Flamant
- Institut de Génomique Fonctionnelle de Lyon (IGFL), INRAE USC1370, CNRS (UMR5242), ENS, Lyon, France
| | - Jing Wang
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France.,Department of ENT and Head and Neck Surgery, University Hospital of Montpellier, Montpellier, France
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Giraudet F, Mulliez A, de Resende LM, Beaud L, Benichou T, Brusseau V, Tauveron I, Avan P. Impaired auditory neural performance, another dimension of hearing loss in type-2 diabetes mellitus. DIABETES & METABOLISM 2022; 48:101360. [PMID: 35660525 DOI: 10.1016/j.diabet.2022.101360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
Abstract
AIM to evaluate auditory performance in subjects with poorly controlled type-2 diabetes mellitus, using a simple test battery assessing sensitivity to pure tones and neuronal function. METHODS Enrolled subjects, aged between 23-79 years, reported several auditory dysfunctions. They were tested using pure-tone audiometry, otoacoustic emissions for cochlear-function evaluation, and measurement of middle-ear muscle-reflex thresholds in search of an auditory neuropathy. RESULTS Compared to the standard established for an age-matched normative population, the distribution of averaged pure-tone thresholds in enrolled subjects shifted by about one standard deviation with respect to the normal distribution, in line with past reports of mild sensorineural hearing impairment in diabetes, even though many diabetic subjects fell well within the normative interval of audiometric thresholds. Otoacoustic emissions showed that pure-tone thresholds correctly predicted the status of cochlear sensory cells that, by amplifying sound, ensure normal hearing sensitivity. Whereas the observed hearing losses should not have affected the acoustic levels above which the protective middle-ear muscle reflex is triggered by intense sounds, this reflex was undetectable in around 40% enrolled subjects, a marker of auditory neuropathy. CONCLUSION auditory-neural function should be evaluated to identify diabetic subjects whose hearing is impaired. Simple automatic tests are available for this purpose, for example middle-ear muscle reflex detection, which turns out to be more sensitive than the standard audiogram.
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Affiliation(s)
- Fabrice Giraudet
- Laboratoire de Biophysique Neurosensorielle, INSERM, Université Clermont Auvergne, Clermont-Ferrand, France; Laboratoire d'Expertise Auditive, AUDIKA, Clermont-Ferrand, France.
| | - Aurélien Mulliez
- Direction de la Recherche Clinique et de l'Innovation, CHU, Clermont-Ferrand, France.
| | - Luciana Macedo de Resende
- Laboratoire de Biophysique Neurosensorielle, INSERM, Université Clermont Auvergne, Clermont-Ferrand, France.
| | - Ludivine Beaud
- Laboratoire de Biophysique Neurosensorielle, INSERM, Université Clermont Auvergne, Clermont-Ferrand, France.
| | - Thomas Benichou
- Service Endocrinologie Diabète et Maladies Métaboliques, CHU, Clermont-Ferrand, France.
| | - Valentin Brusseau
- Service Endocrinologie Diabète et Maladies Métaboliques, CHU, Clermont-Ferrand, France.
| | - Igor Tauveron
- Service Endocrinologie Diabète et Maladies Métaboliques, CHU, Clermont-Ferrand, France; Laboratoire Génétique Reproduction Développement, INSERM, Université Clermont Auvergne.
| | - Paul Avan
- Laboratoire de Biophysique Neurosensorielle, INSERM, Université Clermont Auvergne, Clermont-Ferrand, France; Institut de l'Audition, Institut Pasteur, INSERM, Paris.
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13
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Thipmaungprom Y, Prawanta E, Leelasiriwong W, Thammachoti P, Roongthumskul Y. Intermodulation distortions from an array of active nonlinear oscillators. CHAOS (WOODBURY, N.Y.) 2021; 31:123106. [PMID: 34972317 DOI: 10.1063/5.0063678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/08/2021] [Indexed: 06/14/2023]
Abstract
Coupling is critical in nonlinear dynamical systems. It affects the stabilities of individual oscillators as well as the characteristics of their response to external forces. In the auditory system, the mechanical coupling between sensory hair cells has been proposed as a mechanism that enhances the inner ear's sensitivity and frequency discrimination. While extensive studies investigate the effects of coupling on the detection of a sinusoidal signal, the role of coupling underlying the response to a complex tone remains elusive. In this study, we measured the acoustic intermodulation distortions (IMDs) produced by the inner ears of two frog species stimulated simultaneously by two pure tones. The distortion intensity level displayed multiple peaks across stimulus frequencies, in contrast to the generic response from a single nonlinear oscillator. The multiple-peaked pattern was altered upon varying the stimulus intensity or an application of a perturbation tone near the distortion frequency. Numerical results of IMDs from a chain of coupled active nonlinear oscillators driven by two sinusoidal forces reveal the effects of coupling on the variation profile of the distortion amplitude. When the multiple-peaked pattern is observed, the chain's motion at the distortion frequency displays both a progressive wave and a standing wave. The latter arises due to coupling and is responsible for the multiple-peaked pattern. Our results illustrate the significance of mechanical coupling between active hair cells in the generation of auditory distortions, as a mechanism underlying the formation of in vivo standing waves of distortion signals.
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Affiliation(s)
- Yanathip Thipmaungprom
- Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Ekkanat Prawanta
- Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Wisit Leelasiriwong
- Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Panupong Thammachoti
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Yuttana Roongthumskul
- Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
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14
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Sisto R, Belardinelli D, Moleti A. Fluid focusing and viscosity allow high gain and stability of the cochlear response. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 150:4283. [PMID: 34972263 DOI: 10.1121/10.0008940] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 11/11/2021] [Indexed: 06/14/2023]
Abstract
This paper discusses the role of two-dimensional (2-D)/three-dimensional (3-D) cochlear fluid hydrodynamics in the generation of the large nonlinear dynamical range of the basilar membrane (BM) and pressure response, in the decoupling between cochlear gain and tuning, and in the dynamic stabilization of the high-gain BM response in the peak region. The large and closely correlated dependence on stimulus level of the BM velocity and fluid pressure gain [Dong, W., and Olson, E. S. (2013). Biophys. J. 105(4), 1067-1078] is consistent with a physiologically oriented schematization of the outer hair cell (OHC) mechanism if two hydrodynamic effects are accounted for: amplification of the differential pressure associated with a focusing phenomenon, and viscous damping at the BM-fluid interface. The predictions of the analytical 2-D Wentzel-Kramers-Brillouin (WKB) approach are compared to solutions of a 3-D finite element model, showing that these hydrodynamic phenomena yield stable high-gain response in the peak region and a smooth transition among models with different effectiveness of the active mechanism, mimicking the cochlear nonlinear response over a wide stimulus level range. This study explains how an effectively anti-damping nonlinear outer hair cells (OHC) force may yield large BM and pressure dynamical ranges along with an almost level-independent admittance.
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Affiliation(s)
- Renata Sisto
- INAIL, Department of Medicine, Epidemiology and Hygiene, Monte Porzio Catone (RM), Italy
| | - Daniele Belardinelli
- INAIL, Department of Medicine, Epidemiology and Hygiene, Monte Porzio Catone (RM), Italy
| | - Arturo Moleti
- Physics Department, University of Rome Tor Vergata, Rome, Italy
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15
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He W, Ren T. The origin of mechanical harmonic distortion within the organ of Corti in living gerbil cochleae. Commun Biol 2021; 4:1008. [PMID: 34433876 PMCID: PMC8387486 DOI: 10.1038/s42003-021-02540-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 08/11/2021] [Indexed: 11/09/2022] Open
Abstract
Although auditory harmonic distortion has been demonstrated psychophysically in humans and electrophysiologically in experimental animals, the cellular origin of the mechanical harmonic distortion remains unclear. To demonstrate the outer hair cell-generated harmonics within the organ of Corti, we measured sub-nanometer vibrations of the reticular lamina from the apical ends of the outer hair cells in living gerbil cochleae using a custom-built heterodyne low-coherence interferometer. The harmonics in the reticular lamina vibration are significantly larger and have broader spectra and shorter latencies than those in the basilar membrane vibration. The latency of the second harmonic is significantly greater than that of the fundamental at low stimulus frequencies. These data indicate that the mechanical harmonics are generated by the outer hair cells over a broad cochlear region and propagate from the generation sites to their own best-frequency locations.
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Affiliation(s)
- Wenxuan He
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, USA
| | - Tianying Ren
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, USA.
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16
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Abstract
Congenital hearing loss is the most common birth defect, estimated to affect 2-3 in every 1000 births. Currently there is no cure for hearing loss. Treatment options are limited to hearing aids for mild and moderate cases, and cochlear implants for severe and profound hearing loss. Here we provide a literature overview of the environmental and genetic causes of congenital hearing loss, common animal models and methods used for hearing research, as well as recent advances towards developing therapies to treat congenital deafness. © 2021 The Authors.
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Affiliation(s)
- Justine M Renauld
- Department of Otolaryngology, Head & Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Martin L Basch
- Department of Otolaryngology, Head & Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Department of Genetics and Genome Sciences, Case Western Reserve School of Medicine, Cleveland, Ohio.,Department of Biology, Case Western Reserve University, Cleveland, Ohio.,Department of Otolaryngology, Head & Neck Surgery, University Hospitals, Cleveland, Ohio
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17
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Ballesteros A, Fitzgerald TS, Swartz KJ. Expression of a membrane-targeted fluorescent reporter disrupts auditory hair cell mechanoelectrical transduction and causes profound deafness. Hear Res 2021; 404:108212. [PMID: 33667877 PMCID: PMC8035305 DOI: 10.1016/j.heares.2021.108212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 02/11/2021] [Accepted: 02/13/2021] [Indexed: 11/22/2022]
Abstract
The reporter mT/mG mice expressing a membrane-targeted fluorescent protein are becoming widely used to study the auditory and vestibular system due to its versatility. Here we show that high expression levels of the fluorescent mtdTomato reporter affect the function of the sensory hair cells and the auditory performance of mT/mG transgenic mice. Auditory brainstem responses and distortion product otoacoustic emissions revealed that adult mT/mG homozygous mice are profoundly deaf, whereas heterozygous mice present high frequency loss. We explore whether this line would be useful for studying and visualizing the membrane of auditory hair cells by airyscan super-resolution confocal microscopy. Membrane localization of the reporter was observed in hair cells of the cochlea, facilitating imaging of both cell bodies and stereocilia bundles without altering cellular architecture or the expression of the integral membrane motor protein prestin. Remarkably, hair cells from mT/mG homozygous mice failed to uptake the FM1-43 dye and to locate TMC1 at the stereocilia, indicating defective mechanotransduction machinery. Our work emphasizes that precautions must be considered when working with reporter mice and highlights the potential role of the cellular membrane in maintaining functional hair cells and ensuring proper hearing.
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Affiliation(s)
- Angela Ballesteros
- Molecular Physiology and Biophysics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Tracy S Fitzgerald
- Mouse Auditory Testing Core, National Institute on Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, United States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
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18
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Bader K, Dierkes L, Braun LH, Gummer AW, Dalhoff E, Zelle D. Test-retest reliability of distortion-product thresholds compared to behavioral auditory thresholds. Hear Res 2021; 406:108232. [PMID: 33984603 DOI: 10.1016/j.heares.2021.108232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/15/2021] [Accepted: 03/24/2021] [Indexed: 10/21/2022]
Abstract
When referred to baseline measures, serial monitoring of pure-tone behavioral thresholds and distortion-product otoacoustic emissions (DPOAEs) can be used to detect the progression of cochlear damage. Semi-logarithmic DPOAE input-output (I/O) functions enable the computation of estimated distortion-product thresholds (EDPTs) by means of linear regression, a metric that provides a quantitative estimate of hearing loss due to cochlear-amplifier degradation. DPOAE wave interference and a suboptimal choice of stimulus levels limit the accuracy of EDPTs. This work identifies the test-retest reliability of EDPTs derived from short-pulse DPOAE level maps (EDPTLM), a method that circumvents limitations associated with both wave interference and suboptimal choice of stimulus levels. The test-retest reliability was compared to that of EDPTs derived from semi-logarithmic I/O functions (EDPTI/O) and that of behavioral thresholds acquired with pure-tone audiometry (PTA) and modified Békésy tracking audiometry (TA) to provide a foundation for identifying and interpreting significant threshold shifts. The DPOAE-based auditory thresholds (EDPTLM and EDPTI/O) and behavioral thresholds (PTA and TA) were recorded seven times within three months at 14 frequencies with f2 = 1-14 kHz in 20 ears from ten subjects with normal hearing (4PTA0.5-4kHz < 20 dB HL). To obtain EDPTLM, short-pulse DPOAEs were recorded using 21 L1,L2 pairs. Reconstruction of DPOAE growth behavior as a function of L1 and L2 using nonlinear curve fitting enabled the derivation of EDPTLM for each frequency. Test-retest reliability was determined using three different approaches: 1) centered thresholds, 2) average threshold differences, and 3) average absolute threshold differences, between each possible test session (N = 21). Test-retest reliability based on centered thresholds and average threshold differences showed no statistically significant difference between EDPTLM, EDPTI/O, PTA, and TA for the pooled analysis incorporating all stimulus frequencies. Average absolute threshold differences presented small but significant differences in test-retest reliability with median values of 3.00 dB for PTA, 3.20 dB for TA, 3.34 dB for EDPTLM, and 3.51 dB for EDPTI/O. A considerable frequency dependence of test-retest reliability was found; namely, the highest test-retest reliability was for EDPTLM at f2 = 11 - 14 kHz. Otherwise, at lower frequencies, the highest test-retest reliability was for TA at f2 =1 - 2 kHz. Overall, the test-retest reliability of EDPTLM was better than that of EDPTI/O and was similar to that for behavioral thresholds. Hence, deriving EDPTLM from individual level maps is a promising and sensitive method for objectively monitoring the state of the cochlea. Furthermore, the detection of an equidirectional threshold change at a single frequency in both EDPTLM and TA might allow reducing the threshold shift as indication of a follow-up examination from the clinical standard of 10 dB down to 5 dB. This stricter indicator might be beneficial when monitoring cochlear damage, for example ototoxicity, in the presence of (remnant) cochlear amplification at baseline.
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Affiliation(s)
- Katharina Bader
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Linda Dierkes
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Lore Helene Braun
- Department of Radiooncology, Eberhard-Karls-University Tübingen, Hoppe-Seyler-Straße 3, 72076 Tübingen, Germany; Current address: Department of Radiooncology, Marienhospital Stuttgart, Böheimstraße 37, 70199 Stuttgart, Germany
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany; Current address: Redwave Medical GmbH, Hans-Knöll-Str. 6, 07745 Jena, Germany
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19
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Wilson US, Browning-Kamins J, Durante AS, Boothalingam S, Moleti A, Sisto R, Dhar S. Cochlear tuning estimates from level ratio functions of distortion product otoacoustic emissions. Int J Audiol 2021; 60:890-899. [PMID: 33612052 DOI: 10.1080/14992027.2021.1886352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Objective: Distortion product otoacoustic emission (DPOAE) levels plotted as a function of stimulus frequency ratio demonstrate a bandpass shape. This bandpass shape is narrower at higher frequencies compared to lower frequencies and thus has been thought to be related to cochlear mechanical tuning.Design: However, the frequency- and level-dependence of these functions above 8 kHz is largely unknown. Furthermore, how tuning estimates from these functions are related to behavioural tuning is not fully understood.Study Sample: From experiment 1, we report DPOAE level ratio functions (LRF) from seven normal-hearing, young-adults for f2 = 0.75-16 kHz and two stimulus levels of 62/52 and 52/37 dB FPL. We found that LRFs became narrower as a function of increasing frequency and decreasing level.Results: Tuning estimates from these functions increased as expected from 1-8 kHz. In experiment 2, we compared tuning estimates from DPOAE LRF to behavioural tuning in 24 normal-hearing, young adults for 1 and 4 kHz and found that behavioural tuning generally predicted DPOAE LRF estimated tuning.Conclusions: Our findings suggest that DPOAE LRFs generally reflect the tuning profile consistent with basilar membrane, neural, and behavioural tuning. However, further investigations are warranted to fully determine the use of DPOAE LRF as a clinical measure of cochlear tuning.
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Affiliation(s)
- Uzma Shaheen Wilson
- Roxelyn and Richard Pepper Department of Communication Sciences & Disorders, Northwestern University, Evanston, IL, USA
| | - Jenna Browning-Kamins
- Roxelyn and Richard Pepper Department of Communication Sciences & Disorders, Northwestern University, Evanston, IL, USA
| | | | | | - Arturo Moleti
- Physics Department, University of Roma Tor Vergata, Rome, Italy
| | | | - Sumitrajit Dhar
- Roxelyn and Richard Pepper Department of Communication Sciences & Disorders, Northwestern University, Evanston, IL, USA.,Knowles Hearing Center, Northwestern University, Evanston, IL, USA
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20
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Lin X, Meenderink SWF, Stomackin G, Jung TT, Martin GK, Dong W. Forward and Reverse Middle Ear Transmission in Gerbil with a Normal or Spontaneously Healed Tympanic Membrane. J Assoc Res Otolaryngol 2021; 22:261-274. [PMID: 33591494 DOI: 10.1007/s10162-020-00779-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/19/2020] [Indexed: 11/25/2022] Open
Abstract
Tympanic membranes (TM) that have healed spontaneously after perforation present abnormalities in their structural and mechanical properties; i.e., they are thickened and abnormally dense. These changes result in a deterioration of middle ear (ME) sound transmission, which is clinically presented as a conductive hearing loss (CHL). To fully understand the ME sound transmission under TM pathological conditions, we created a gerbil model with a controlled 50% pars tensa perforation, which was left to heal spontaneously for up to 4 weeks (TM perforations had fully sealed after 2 weeks). After the recovery period, the ME sound transmission, both in the forward and reverse directions, was directly measured with two-tone stimulation. Measurements were performed at the input, the ossicular chain, and output of the ME system, i.e., at the TM, umbo, and scala vestibuli (SV) next to the stapes. We found that variations in ME transmission in forward and reverse directions were not symmetric. In the forward direction, the ME pressure gain decreased in a frequency-dependent manner, with smaller loss (within 10 dB) at low frequencies and more dramatic loss at high frequency regions. The loss pattern was mainly from the less efficient acoustical to mechanical coupling between the TM and umbo, with little changes along the ossicular chain. In the reverse direction, the variations in these ears are relatively smaller. Our results provide detailed functional observations that explain CHL seen in clinical patients with abnormal TM, e.g., caused by otitis media, that have healed spontaneously after perforation or post-tympanoplasty, especially at high frequencies. In addition, our data demonstrate that changes in distortion product otoacoustic emissions (DPOAEs) result from altered ME transmission in both the forward and reverse direction by a reduction of the effective stimulus levels and less efficient transfer of DPs from the ME into the ear canal. This confirms that DPOAEs can be used to assess both the health of the cochlea and the middle ear.
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Affiliation(s)
- Xiaohui Lin
- VA Loma Linda Healthcare System, Loma Linda, CA, 92374, USA
| | | | | | - Timothy T Jung
- VA Loma Linda Healthcare System, Loma Linda, CA, 92374, USA.,Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA, 92350, USA
| | - Glen K Martin
- VA Loma Linda Healthcare System, Loma Linda, CA, 92374, USA.,Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA, 92350, USA
| | - Wei Dong
- VA Loma Linda Healthcare System, Loma Linda, CA, 92374, USA. .,Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA, 92350, USA.
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21
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Sisto R, Moleti A. Low-passed outer hair cell response and apical-basal transition in a nonlinear transmission-line cochlear model. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:1296. [PMID: 33639784 DOI: 10.1121/10.0003569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
The low-pass characteristic of the outer hair cell (OHC) voltage response to mechanical stimulation could be considered a serious problem for cochlear models aiming at explaining high-frequency active amplification by introducing instantaneous nonlinear terms because active gain would dramatically decrease at high frequency. Evidence from experimental studies by Nam and Fettiplace [(2012). PloS One 7, e50572] suggests that the local cutoff frequency significantly increases approaching the cochlear base, somehow mitigating this problem. In this study, low-pass filtering of an internal force term, derived from a physiologically plausible OHC schematization by Lu, Zhak, Dallos, and Sarpeshkar [(2006). Hear. Res. 214, 45-67] is included in a simple one-dimensional (1-D) two-degrees-of-freedom transmission-line model by Sisto, Shera, Altoè, and Moleti [(2019). J. Acoust. Soc. Am. 146, 1685-1695] The frequency dependence of the low-pass filter phase-shift naturally yields a transition from sharp tuning and wide dynamical gain range in the basal cochlea to low tuning and poor dynamical range in the apical region. On the other hand, the frequency-dependent attenuation of low-pass filtering makes it more difficult to obtain the high gain (40-50 dB) of the basal basilar membrane response that is experimentally measured in mammals at low stimulus levels. Pressure focusing in the short-wave resonant region, which is not accounted for in this 1-D model, may help in acquiring the additional gain necessary to match the experimental data.
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Affiliation(s)
- Renata Sisto
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Istituto Nazionale per l'Assicurazione contro gli Infortuni sul Lavoro, Via di Fontana Candida, 1, 00078 Monte Porzio Catone, Rome, Italy
| | - Arturo Moleti
- Physics Department, University of Roma Tor Vergata, Via della Ricerca Scientifica, 1, 00133 Rome, Italy
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22
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Waqas M, Us-Salam I, Bibi Z, Wang Y, Li H, Zhu Z, He S. Stem Cell-Based Therapeutic Approaches to Restore Sensorineural Hearing Loss in Mammals. Neural Plast 2020; 2020:8829660. [PMID: 32802037 PMCID: PMC7416290 DOI: 10.1155/2020/8829660] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/01/2020] [Accepted: 07/03/2020] [Indexed: 12/13/2022] Open
Abstract
The hair cells that reside in the cochlear sensory epithelium are the fundamental sensory structures responsible for understanding the mechanical sound waves evoked in the environment. The intense damage to these sensory structures may result in permanent hearing loss. The present strategies to rehabilitate the hearing function include either hearing aids or cochlear implants that may recover the hearing capability of deaf patients to a limited extent. Therefore, much attention has been paid on developing regenerative therapies to regenerate/replace the lost hair cells to treat the damaged cochlear sensory epithelium. The stem cell therapy is a promising approach to develop the functional hair cells and neuronal cells from endogenous and exogenous stem cell pool to recover hearing loss. In this review, we specifically discuss the potential of different kinds of stem cells that hold the potential to restore sensorineural hearing loss in mammals and comprehensively explain the current therapeutic applications of stem cells in both the human and mouse inner ear to regenerate/replace the lost hair cells and spiral ganglion neurons.
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Affiliation(s)
- Muhammad Waqas
- Department of Biotechnology, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal Campus, Karachi, Pakistan
- Department of Otolaryngology Head and Neck, Nanjing Tongren Hospital, School of Medicine, Southeast University, Nanjing 211102, China
| | - Iram Us-Salam
- Department of Biotechnology, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal Campus, Karachi, Pakistan
| | - Zainab Bibi
- Department of Biotechnology, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal Campus, Karachi, Pakistan
| | - Yunfeng Wang
- ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai 200031, China
| | - He Li
- Department of Otolaryngology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou City, 325000 Zhejiang Province, China
| | - Zhongshou Zhu
- Department of Otolaryngology, Ningde Municipal Hospital Affiliated of Fujian Medical University (Ningde Institute of Otolaryngology), Ningde, Fujian 352100, China
| | - Shuangba He
- Department of Otolaryngology Head and Neck, Nanjing Tongren Hospital, School of Medicine, Southeast University, Nanjing 211102, China
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23
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Wang K, Tang D, Ma J, Sun S. Auditory Neural Plasticity in Tinnitus Mechanisms and Management. Neural Plast 2020; 2020:7438461. [PMID: 32684922 PMCID: PMC7349625 DOI: 10.1155/2020/7438461] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/15/2020] [Accepted: 06/20/2020] [Indexed: 11/24/2022] Open
Abstract
Tinnitus, which is the perception of sound in the absence of a corresponding external acoustic stimulus, including change of hearing and neural plasticity, has become an increasingly important ailment affecting the daily life of a considerable proportion of the population and causing significant burdens for both the affected individuals and society as a whole. Here, we briefly review the epidemiology and classification of tinnitus, and the currently available treatments are discussed in terms of the available evidence for their mechanisms and efficacy. The conclusion drawn from the available evidence is that there is no specific medication for tinnitus treatment at present, and tinnitus management might provide better solutions. Therapeutic interventions for tinnitus should be based on a comprehensive understanding of the etiology and features of individual cases of tinnitus, and more high quality and large-scale research studies are urgently needed to develop more efficacious medications.
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Affiliation(s)
- Kunkun Wang
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200031, China
| | - Dongmei Tang
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200031, China
| | - Jiaoyao Ma
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200031, China
| | - Shan Sun
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200031, China
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Distinct roles of stereociliary links in the nonlinear sound processing and noise resistance of cochlear outer hair cells. Proc Natl Acad Sci U S A 2020; 117:11109-11117. [PMID: 32358189 DOI: 10.1073/pnas.1920229117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Outer hair cells (OHCs) play an essential role in hearing by acting as a nonlinear amplifier which helps the cochlea detect sounds with high sensitivity and accuracy. This nonlinear sound processing generates distortion products, which can be measured as distortion-product otoacoustic emissions (DPOAEs). The OHC stereocilia that respond to sound vibrations are connected by three kinds of extracellular links: tip links that connect the taller stereocilia to shorter ones and convey force to the mechanoelectrical transduction channels, tectorial membrane-attachment crowns (TM-ACs) that connect the tallest stereocilia to one another and to the overlying TM, and horizontal top connectors (HTCs) that link adjacent stereocilia. While the tip links have been extensively studied, the roles that the other two types of links play in hearing are much less clear, largely because of a lack of suitable animal models. Here, while analyzing genetic combinations of tubby mice, we encountered models missing both HTCs and TM-ACs or HTCs alone. We found that the tubby mutation causes loss of both HTCs and TM-ACs due to a mislocalization of stereocilin, which results in OHC dysfunction leading to severe hearing loss. Intriguingly, the addition of the modifier allele modifier of tubby hearing 1 in tubby mice selectively rescues the TM-ACs but not the HTCs. Hearing is significantly rescued in these mice with robust DPOAE production, indicating an essential role of the TM-ACs but not the HTCs in normal OHC function. In contrast, the HTCs are required for the resistance of hearing to damage caused by noise stress.
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Zelle D, Bader K, Dierkes L, Gummer AW, Dalhoff E. Derivation of input-output functions from distortion-product otoacoustic emission level maps. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:3169. [PMID: 32486784 DOI: 10.1121/10.0001142] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
Distortion-product otoacoustic emissions (DPOAEs) emerge from the cochlea when elicited with two tones of frequencies f1 and f2. DPOAEs mainly consist of two components, a nonlinear-distortion and a coherent-reflection component. Input-output (I/O) functions of DPOAE pressure at the cubic difference frequency, fDP=2f1-f2, enable the computation of estimated distortion-product thresholds (EDPTs), offering a noninvasive approach to estimate auditory thresholds. However, wave interference between the DPOAE components and suboptimal stimulus-level pairs reduces the accuracy of EDPTs. Here, the amplitude P of the nonlinear-distortion component is extracted from short-pulse DPOAE time signals. DPOAE level maps representing the growth behavior of P in L1,L2 space are recorded for 21 stimulus-level pairs and 14 frequencies with f2=1 to 14 kHz (f2/f1=1.2) from 20 ears. Reproducing DPOAE growth behavior using a least-squares fit approach enables the derivation of ridge-based I/O functions from model level maps. Objective evaluation criteria assess the fit results and provide EDPTs, which correlate significantly with auditory thresholds (p < 0.001). In conclusion, I/O functions derived from model level maps provide EDPTs with high precision but without the need of predefined optimal stimulus-level pairs.
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Affiliation(s)
- Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Katharina Bader
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn- Straße 5, 72076 Tübingen, Germany
| | - Linda Dierkes
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn- Straße 5, 72076 Tübingen, Germany
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
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Two-tone distortion in reticular lamina vibration of the living cochlea. Commun Biol 2020; 3:35. [PMID: 31965040 PMCID: PMC6972885 DOI: 10.1038/s42003-020-0762-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/06/2020] [Indexed: 11/09/2022] Open
Abstract
It has been demonstrated that isolated auditory sensory cells, outer hair cells, can generate distortion products at low frequencies. It remains unknown, however, whether or not motile outer hair cells are able to generate two-tone distortion at high frequencies in living cochleae under the mechanical loads caused by surounding tissues and fluids. By measuring sub-nanometer vibration directly from the apical ends of outer hair cells using a custom-built heterodyne low-coherence interferometer, here we show outer hair cell-generated two-tone distortion in reticular lamina motion in the living cochlea. Reticular-lamina distortion is significantly greater and occurs at a broader frequency range than that of the basilar membrane. Contrary to expectations, our results indicate that motile outer hair cells are capable of generating two-tone distortion in vivo not only at the locations tuned to primary tones but also at a broad region basal to these locations. Ren et al. used an in house heterodyne low-coherence interferometer to measure sub-nanometer vibrations, a proxy for distortion products, in living cochleae of gerbils. They were able to locate the generation source of the outer hair cell in the reticular lamina versus the basilar membrane in vivo.
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Duron J, Monconduit L, Avan P. Auditory Brainstem Changes in Timing may Underlie Hyperacusis in a Salicylate-induced Acute Rat Model. Neuroscience 2019; 426:129-140. [PMID: 31846750 DOI: 10.1016/j.neuroscience.2019.11.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 11/23/2019] [Accepted: 11/25/2019] [Indexed: 10/25/2022]
Abstract
Hyperacusis, an exaggerated, sometimes painful perception of loudness even for soft sounds, is a poorly understood distressing condition. While the involvement of modified gain of central auditory neurons and the influence of nonauditory brain regions are well-documented, the issue of where in the auditory system these abnormalities arise remains open, particularly when hyperacusis comes without sensorineural hearing loss. Here we used acute intraperitoneal administration of sodium salicylate (150 mg/kg) in rats, enough to produce > 10-dB decrease in acoustic startle threshold with mild hearing loss at low frequencies (<10 kHz). Anesthesia, necessary for middle-ear-reflex (MEMR) threshold measurements, abolished the olivocochlear efferent reflex but not the MEMR acting on frequencies < 10 kHz, and its mean threshold increased from 55 dB SPL in controls to 80 dB SPL in salicylate-treated animals 60-90 minutes after injection, with an about 3-dB increase in acoustic energy reaching the cochlea. The mean latencies of auditory brainstem-evoked responses (ABR) conspicuously decreased after salicylate, by 0.25 millisecond at 6 kHz at every level, a frequency-dependent effect absent above 12 kHz. A generic model of loudness based upon cross-frequency coincidence detection predicts that with such timing changes, a transient sound may seem as loud at <40 dB SPL as it does in controls at >60 dB SPL. Candidate circuits able to act at the same time on the startle reflex, the MEMR and ABRs may be serotoninergic, as salicylate is known to increase brain serotonin and 5-HT neurons participate in MEMR and ABR circuits.
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Affiliation(s)
- Julie Duron
- School of Medicine, University Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France; UMR INSERM 1107, School of Medicine, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France; Audioconsulting, Audition Conseil, 16 rue Blatin, 63000 Clermont-Ferrand, France.
| | - Lénaic Monconduit
- School of Dentistry, University Clermont Auvergne, 2 Rue de Braga, 63100 Clermont-Ferrand, France; UMR INSERM 1107, School of Medicine, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France.
| | - Paul Avan
- School of Medicine, University Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France; UMR INSERM 1107, School of Medicine, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France; Centre Jean Perrin, 30 rue Montalembert, 63000 Clermont-Ferrand, France.
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28
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Richardson GP, Petit C. Hair-Bundle Links: Genetics as the Gateway to Function. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033142. [PMID: 30617060 DOI: 10.1101/cshperspect.a033142] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Up to five distinct cell-surface specializations interconnect the stereocilia and the kinocilium of the mature hair bundle in some species: kinocilial links, tip links, top connectors, shaft connectors, and ankle links. In developing hair bundles, transient lateral links are prominent. Mutations in genes encoding proteins associated with these links cause Usher deafness/blindness syndrome or nonsyndromic (isolated) forms of human hereditary deafness, and mice with constitutive or conditional alleles of these genes have provided considerable insight into the molecular composition and function of the different links. We describe the structure of these links and review evidence showing CDH23 and PCDH15 are components of the tip, kinocilial, and transient-lateral links, that stereocilin (STRC) and protein tyrosine phosphatase (PTPRQ) are associated with top and shaft connectors, respectively, and that USH2A and ADGRV1 are associated with the ankle links. Whereas tip links are required for mechanoelectrical transduction, all link proteins play key roles in the normal development and/or the maintenance of hair bundle structure and function. Recent crystallographic and single-particle analyses of PCDH15 and CDH23 provide insight as to how the structure of tip link may contribute to the elastic element predicted to lie in series with the hair cell's mechanoelectrical transducer channel.
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Affiliation(s)
- Guy P Richardson
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom
| | - Christine Petit
- Institut Pasteur, 75724 Paris Cedex 15, France.,Collège de France, 75231 Paris Cedex 05, France
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Otogelin, otogelin-like, and stereocilin form links connecting outer hair cell stereocilia to each other and the tectorial membrane. Proc Natl Acad Sci U S A 2019; 116:25948-25957. [PMID: 31776257 DOI: 10.1073/pnas.1902781116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The function of outer hair cells (OHCs), the mechanical actuators of the cochlea, involves the anchoring of their tallest stereocilia in the tectorial membrane (TM), an acellular structure overlying the sensory epithelium. Otogelin and otogelin-like are TM proteins related to secreted epithelial mucins. Defects in either cause the DFNB18B and DFNB84B genetic forms of deafness, respectively, both characterized by congenital mild-to-moderate hearing impairment. We show here that mutant mice lacking otogelin or otogelin-like have a marked OHC dysfunction, with almost no acoustic distortion products despite the persistence of some mechanoelectrical transduction. In both mutants, these cells lack the horizontal top connectors, which are fibrous links joining adjacent stereocilia, and the TM-attachment crowns coupling the tallest stereocilia to the TM. These defects are consistent with the previously unrecognized presence of otogelin and otogelin-like in the OHC hair bundle. The defective hair bundle cohesiveness and the absence of stereociliary imprints in the TM observed in these mice have also been observed in mutant mice lacking stereocilin, a model of the DFNB16 genetic form of deafness, also characterized by congenital mild-to-moderate hearing impairment. We show that the localizations of stereocilin, otogelin, and otogelin-like in the hair bundle are interdependent, indicating that these proteins interact to form the horizontal top connectors and the TM-attachment crowns. We therefore suggest that these 2 OHC-specific structures have shared mechanical properties mediating reaction forces to sound-induced shearing motion and contributing to the coordinated displacement of stereocilia.
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Roberts B, Neitzel RL. Noise exposure limit for children in recreational settings: Review of available evidence. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3922. [PMID: 31795717 DOI: 10.1121/1.5132540] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
It is universally recognized that prolonged exposure to high levels of non-impulsive noise will lead to noise-induced hearing loss. These high levels of noise have traditionally been found in an occupational setting, but exposure to high levels of noise is increasingly common in recreational settings. There is currently no established acceptable risk of hearing loss in children. This review assumed that the most appropriate exposure limit for recreational noise exposure in children would be developed to protect 99% of children from hearing loss exceeding 5 dB at the 4 kHz audiometric test frequency after 18 years of noise exposure. Using the ISO 1999:2013 model for predicting hearing loss, it was estimated that noise exposure equivalent to an 8-h average exposure (LEX) of 82 dBA would result in about 4.2 dB or less of hearing loss in 99% of children after 18 years of exposure. The 8-h LEX was reduced to 80 dB to include a 2 dB margin of safety. This 8-h LEX of 80 dBA is estimated to result in 2.1 dB or less of hearing loss in 99% of children after 18 years of exposure. This is equivalent to 75 dBA as a 24-h equivalent continuous average sound level.
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Affiliation(s)
- Benjamin Roberts
- Cardno ChemRisk, 30 North LaSalle Suite 3910, Chicago, Illinois 60602, USA
| | - Richard L Neitzel
- Department of Environmental Health Sciences, University of Michigan, School of Public Health, Ann Arbor, Michigan 48109, USA
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Helmstaedter V, Lenarz T, Erfurt P, Kral A, Baumhoff P. The Summating Potential Is a Reliable Marker of Electrode Position in Electrocochleography: Cochlear Implant as a Theragnostic Probe. Ear Hear 2019; 39:687-700. [PMID: 29251689 DOI: 10.1097/aud.0000000000000526] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE For the increasing number of cochlear implantations in subjects with residual hearing, hearing preservation, and thus the prevention of implantation trauma, is crucial. A method for monitoring the intracochlear position of a cochlear implant (CI) and early indication of imminent cochlear trauma would help to assist the surgeon to achieve this goal. The aim of this study was to evaluate the reliability of the different electric components recorded by an intracochlear electrocochleography (ECochG) as markers for the cochleotopic position of a CI. The measurements were made directly from the CI, combining intrasurgical diagnostics with the therapeutical use of the CI, thus, turning the CI into a "theragnostic probe." DESIGN Intracochlear ECochGs were measured in 10 Dunkin Hartley guinea pigs of either sex, with normal auditory brainstem response thresholds. All subjects were fully implanted (4 to 5 mm) with a custom six contact CI. The ECochG was recorded simultaneously from all six contacts with monopolar configuration (retroauricular reference electrode). The gross ECochG signal was filtered off-line to separate three of its main components: compound action potential, cochlear microphonic, and summating potential (SP). Additionally, five cochleae were harvested and histologically processed to access the spatial position of the CI contacts. Both ECochG data and histological reconstructions of the electrode position were fitted with the Greenwood function to verify the reliability of the deduced cochleotopic position of the CI. RESULTS SPs could be used as suitable markers for the frequency position of the recording electrode with an accuracy of ±1/4 octave in the functioning cochlea, verified by histology. Cochlear microphonics showed a dependency on electrode position but were less reliable as positional markers. Compound action potentials were not suitable for CI position information but were sensitive to "cochlear health" (e.g., insertion trauma). CONCLUSIONS SPs directly recorded from the contacts of a CI during surgery can be used to access the intracochlear frequency position of the CI. Using SP monitoring, implantation may be stopped before penetrating functioning cochlear regions. If the technique was similarly effective in humans, it could prevent implantation trauma and increase hearing preservation during CI surgery. Diagnostic hardware and software for recording biological signals with a CI without filter limitations might be a valuable add-on to the portfolios of CI manufacturers.
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Affiliation(s)
- Victor Helmstaedter
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany.,Cluster of Excellence "Hearing 4 All" (DFG EXC 1077), Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany.,Cluster of Excellence "Hearing 4 All" (DFG EXC 1077), Hannover, Germany
| | - Peter Erfurt
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Andrej Kral
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany.,Cluster of Excellence "Hearing 4 All" (DFG EXC 1077), Hannover, Germany.,Department of Experimental Otology & Institute of AudioNeuroTechnology (VIANNA), Hannover, Germany
| | - Peter Baumhoff
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany.,Department of Experimental Otology & Institute of AudioNeuroTechnology (VIANNA), Hannover, Germany
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32
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Zelle D, Dalhoff E, Gummer AW. Objective audiometry with DPOAEs : New findings for generation mechanisms and clinical applications. HNO 2019; 65:122-129. [PMID: 28470484 PMCID: PMC5554278 DOI: 10.1007/s00106-016-0267-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background Distortion product otoacoustic emissions (DPOAEs) and transient-evoked otoacoustic emissions (TEOAEs) are sound waves generated as byproducts of the cochlear amplifier. These are measurable in the auditory canal and represent an objective method for diagnosing functional disorders of the inner ear. Conventional DPOAE and TEOAE methods permit detection of hearing impairment, but with less than desirable accuracy. Objective By accounting for DPOAE generation mechanisms, the aim is to improve the accuracy of inner-ear diagnosis. Methods DPOAEs consist of two components, which emerge at different positions along the cochlea and which may cause artifacts due to mutual interference. Here, the two components are separated in the time domain using short stimulus pulses. Optimized stimulus levels facilitate the acquisition of DPOAEs with maximum amplitudes. DPOAE and Békésy audiograms were recorded from 41 subjects in a clinically relevant frequency range of 1.5–6 kHz. Results The short stimulus pulses allowed artifact-free measurement of DPOAEs. Semilogarithmic input–output functions yielded estimated distortion product thresholds, which were significantly correlated with the subjectively acquired Békésy thresholds. In addition, they allowed detection of hearing impairment from 20 dB HL, with 95% sensitivity and only a 5% false-positive rate. This accuracy was achieved with a measurement time of about 1–2 min per frequency. Conclusion Compared to conventional DPOAE and TEOAE methods, separation of DPOAE components using short-pulse DPOAEs in combination with optimized stimulus parameters considerably enhances the accuracy of DPOAEs for diagnosing impairment of the cochlear amplifier.
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Affiliation(s)
- D Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076, Tübingen, Germany
| | - E Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076, Tübingen, Germany
| | - A W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076, Tübingen, Germany.
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Cartagena-Rivera AX, Le Gal S, Richards K, Verpy E, Chadwick RS. Cochlear outer hair cell horizontal top connectors mediate mature stereocilia bundle mechanics. SCIENCE ADVANCES 2019; 5:eaat9934. [PMID: 30801007 PMCID: PMC6382404 DOI: 10.1126/sciadv.aat9934] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 01/10/2019] [Indexed: 05/23/2023]
Abstract
Outer hair cell (OHC) stereocilia bundle deflection opens mechanoelectrical transduction channels at the tips of the stereocilia from the middle and short rows, while bundle cohesion is maintained owing to the presence of horizontal top connectors. Here, we used a quantitative noncontact atomic force microscopy method to investigate stereocilia bundle stiffness and damping, when stimulated at acoustic frequencies and nanometer distances from the bundle. Stereocilia bundle mechanics were determined in stereocilin-deficient mice lacking top connectors and with detached tectorial membrane (Strc -/-/Tecta -/- double knockout) and heterozygous littermate controls (Strc +/-/Tecta -/-). A substantial decrease in bundle stiffness and damping by ~60 and ~74% on postnatal days P13 to P15 was observed when top connectors were absent. Additionally, we followed bundle mechanics during OHC top connectors development between P9 and P15 and quantified the observed increase in OHC bundle stiffness and damping in Strc +/-/Tecta -/- mice while no significant change was detected in Strc -/-/Tecta -/- animals.
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Affiliation(s)
- Alexander X. Cartagena-Rivera
- Section on Auditory Mechanics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sébastien Le Gal
- Unité de Génétique et Physiologie de l’Audition, Institut Pasteur, 75015 Paris, France
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), 75015 Paris, France
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Complexité du Vivant, 75005 Paris, France
| | - Kerianne Richards
- Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elisabeth Verpy
- Unité de Génétique et Physiologie de l’Audition, Institut Pasteur, 75015 Paris, France
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), 75015 Paris, France
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Complexité du Vivant, 75005 Paris, France
| | - Richard S. Chadwick
- Section on Auditory Mechanics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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A mechanoelectrical mechanism for detection of sound envelopes in the hearing organ. Nat Commun 2018; 9:4175. [PMID: 30302006 PMCID: PMC6177430 DOI: 10.1038/s41467-018-06725-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 09/21/2018] [Indexed: 11/22/2022] Open
Abstract
To understand speech, the slowly varying outline, or envelope, of the acoustic stimulus is used to distinguish words. A small amount of information about the envelope is sufficient for speech recognition, but the mechanism used by the auditory system to extract the envelope is not known. Several different theories have been proposed, including envelope detection by auditory nerve dendrites as well as various mechanisms involving the sensory hair cells. We used recordings from human and animal inner ears to show that the dominant mechanism for envelope detection is distortion introduced by mechanoelectrical transduction channels. This electrical distortion, which is not apparent in the sound-evoked vibrations of the basilar membrane, tracks the envelope, excites the auditory nerve, and transmits information about the shape of the envelope to the brain. The sound envelope is important for speech perception. Here, the authors look at mechanisms by which the sound envelope is encoded, finding that it arises from distortion produced by mechanoelectrical transduction channels. Surprisingly, the envelope is not present in basilar membrane vibrations.
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Abstract
Sensorineural hearing impairment is the most common sensory disorder and a major health and socio-economic issue in industrialized countries. It is primarily due to the degeneration of mechanosensory hair cells and spiral ganglion neurons in the cochlea via complex pathophysiological mechanisms. These occur following acute and/or chronic exposure to harmful extrinsic (e.g., ototoxic drugs, noise...) and intrinsic (e.g., aging, genetic) causative factors. No clinical therapies currently exist to rescue the dying sensorineural cells or regenerate these cells once lost. Recent studies have, however, provided renewed hope, with insights into the therapeutic targets allowing the prevention and treatment of ototoxic drug- and noise-induced, age-related hearing loss as well as cochlear cell degeneration. Moreover, genetic routes involving the replacement or corrective editing of mutant sequences or defected genes are showing promise, as are cell-replacement therapies to repair damaged cells for the future restoration of hearing in deaf people. This review begins by recapitulating our current understanding of the molecular pathways that underlie cochlear sensorineural damage, as well as the survival signaling pathways that can provide endogenous protection and tissue rescue. It then guides the reader through to the recent discoveries in pharmacological, gene and cell therapy research towards hearing protection and restoration as well as their potential clinical application.
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Affiliation(s)
- Jing Wang
- INSERM UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; and University of Montpellier, Montpellier, France
| | - Jean-Luc Puel
- INSERM UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; and University of Montpellier, Montpellier, France
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Tamás LT, Lundberg YW, Büki B. Vergence increases the gain of the human angular vestibulo-ocular reflex during peripheral hyposensitivity elicited by cold thermal irrigation. J Vestib Res 2018; 27:265-270. [PMID: 29400687 DOI: 10.3233/ves-170629] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND When viewing a far target, the gain of the horizontal vestibulo-ocular reflex (VOR) is around 1.0, but when viewing a near target there is an increased response. It has been shown that while this convergence-mediated modulation is unaffected by canal plugging and clinically practical transmastoid galvanic stimulation, it is eliminated by a partial peripheral gentamicin lesion. OBJECTIVE The aim of this study was to determine if convergence increases the gain during peripheral hyposensitivity elicited by cold thermal irrigation. METHODS The high frequency VOR gain was measured using video head impulse testing immediately after the cold caloric stimulus in 9 healthy human subjects with the lateral semicircular canals oriented approximately earth-vertical. RESULTS Before caloric irrigation, near viewing (15 cm) increased the average VOR gain by 28% (from 1 to 1.28). Cold (24°C) water irrigation of the right ear decreased the gain to 0.66 (far viewing) and 0.82 (near viewing) (22% difference). Although vergence also increased the gain for impulses to the left to the same degree before caloric stimulus, the caloric irrigation itself (applied to the right ear) did not influence the gain for contralateral impulses. CONCLUSION In our experiments vergence increased the gain of the human angular VOR during peripheral hyposensitivity elicited by cold thermal irrigation. These results suggest that cold irrigation does not abolish the function of the nonlinear/phasic vestibular afferent pathway.
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Affiliation(s)
- László T Tamás
- Department of Otolaryngology, Petz Aladár Teaching Hospital, 9023 Győr, Vasváry Pál u. 2-4., Hungary
| | - Yunxia W Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, NE, USA
| | - Béla Büki
- Department of Otolaryngology, Karl Landsteiner University Hospital Krems, Krems an der Donau, Austria
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Wolter S, Möhrle D, Schmidt H, Pfeiffer S, Zelle D, Eckert P, Krämer M, Feil R, Pilz PKD, Knipper M, Rüttiger L. GC-B Deficient Mice With Axon Bifurcation Loss Exhibit Compromised Auditory Processing. Front Neural Circuits 2018; 12:65. [PMID: 30275816 PMCID: PMC6152484 DOI: 10.3389/fncir.2018.00065] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/02/2018] [Indexed: 12/20/2022] Open
Abstract
Sensory axon T-like branching (bifurcation) in neurons from dorsal root ganglia and cranial sensory ganglia depends on the molecular signaling cascade involving the secreted factor C-type natriuretic peptide, the natriuretic peptide receptor guanylyl cyclase B (GC-B; also known as Npr2) and cGMP-dependent protein kinase I (cGKI, also known as PKGI). The bifurcation of cranial nerves is suggested to be important for information processing by second-order neurons in the hindbrain or spinal cord. Indeed, mice with a spontaneous GC-B loss of function mutation (Npr2cn/cn ) display an impaired bifurcation of auditory nerve (AN) fibers. However, these mice did not show any obvious sign of impaired basal hearing. Here, we demonstrate that mice with a targeted inactivation of the GC-B gene (Npr2 lacZ/lacZ , GC-B KO mice) show an elevation of audiometric thresholds. In the inner ear, the cochlear hair cells in GC-B KO mice were nevertheless similar to those from wild type mice, justified by the typical expression of functionally relevant marker proteins. However, efferent cholinergic feedback to inner and outer hair cells was reduced in GC-B KO mice, linked to very likely reduced rapid efferent feedback. Sound-evoked AN responses of GC-B KO mice were elevated, a feature that is known to occur when the efferent axo-dendritic feedback on AN is compromised. Furthermore, late sound-evoked brainstem responses were significantly delayed in GC-B KO mice. This delay in sound response was accompanied by a weaker sensitivity of the auditory steady state response to amplitude-modulated sound stimuli. Finally, the acoustic startle response (ASR) - one of the fastest auditory responses - and the prepulse inhibition of the ASR indicated significant changes in temporal precision of auditory processing. These findings suggest that GC-B-controlled axon bifurcation of spiral ganglion neurons is important for proper activation of second-order neurons in the hindbrain and is a prerequisite for proper temporal auditory processing likely by establishing accurate efferent top-down control circuits. These data hypothesize that the bifurcation pattern of cranial nerves is important to shape spatial and temporal information processing for sensory feedback control.
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Affiliation(s)
- Steffen Wolter
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Dorit Möhrle
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Sylvia Pfeiffer
- Department of Animal Physiology, University of Tübingen, Tübingen, Germany
| | - Dennis Zelle
- Department of Otolaryngology, Head and Neck Surgery, Physiological Acoustics and Communication, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Philipp Eckert
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Michael Krämer
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Robert Feil
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Peter K D Pilz
- Department of Animal Physiology, University of Tübingen, Tübingen, Germany
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
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Avan P, Normand H, Giraudet F, Gerenton G, Denise P. Noninvasive in-ear monitoring of intracranial pressure during microgravity in parabolic flights. J Appl Physiol (1985) 2018; 125:353-361. [PMID: 29722618 DOI: 10.1152/japplphysiol.00032.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Among possible causes of visual impairment or headache experienced by astronauts in microgravity or postflight and that hamper their performance, elevated intracranial pressure (ICP) has been invoked but never measured for lack of noninvasive methods. The goal of this work was to test two noninvasive methods of ICP monitoring using in-ear detectors of ICP-dependent auditory responses, acoustic and electric, in acute microgravity afforded by parabolic flights. The devices detecting these responses were handheld tablets routinely used in otolaryngology for hearing diagnosis, which were customized for ICP extraction and serviceable by unskilled operators. These methods had been previously validated against invasive ICP measurements in neurosurgery patients. The two methods concurred in their estimation of ICP changes with microgravity, i.e., 11.0 ± 7.7 mmHg for the acoustic method ( n = 7 subjects with valid results out of 30, auditory responses being masked by excessive in-flight noise in 23 subjects) and 11.3 ± 10.6 mmHg for the electric method ( n = 10 subjects with valid results out of 10 tested despite the in-flight noise). These results agree with recent publications using invasive access to cerebrospinal fluid in parabolic flights and suggest that acute microgravity has a moderate average effect on ICP, similar to body tilt from upright to supine, yet with some subjects undergoing large effects whereas others seem immune. The electric in-ear method would be suitable for ICP monitoring in circumstances and with subjects such that invasive measurements are excluded. NEW & NOTEWORTHY In-ear detectors of intracranial pressure-dependent auditory responses allow intracranial pressure to be monitored noninvasively during acute microgravity. The average pressure increase during 20-s long sessions in microgravity is 11 mmHg, comparable with an effect of body tilt. However, intersubject variability is large, with subjects who repeatedly experience from nothing to twice the average effect. A systematic in-flight use would allow the relationship between space adaptation syndrome and ICP to be established or dismissed.
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Affiliation(s)
- Paul Avan
- UMR INSERM 1107, Neurosensory Biophysics, School of Medicine, Université Clermont Auvergne , Clermont-Ferrand , France.,Centre Jean Perrin , Clermont-Ferrand , France
| | - Hervé Normand
- Normandie University, UNICAEN, INSERM, COMETE 14000, Caen , France
| | - Fabrice Giraudet
- UMR INSERM 1107, Neurosensory Biophysics, School of Medicine, Université Clermont Auvergne , Clermont-Ferrand , France
| | - Grégory Gerenton
- UMR INSERM 1107, Neurosensory Biophysics, School of Medicine, Université Clermont Auvergne , Clermont-Ferrand , France
| | - Pierre Denise
- Normandie University, UNICAEN, INSERM, COMETE 14000, Caen , France
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Soliman SE, D'Silva CN, Dimaras H, Dzneladze I, Chan H, Gallie BL. Clinical and genetic associations for carboplatin-related ototoxicity in children treated for retinoblastoma: A retrospective noncomparative single-institute experience. Pediatr Blood Cancer 2018; 65:e26931. [PMID: 29350448 DOI: 10.1002/pbc.26931] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 11/22/2017] [Accepted: 11/24/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND Children with retinoblastoma treated with carboplatin chemotherapy risk moderate to severe, irreversible hearing loss. Based on published evidence, we hypothesized that ototoxicity risk is associated with clinical parameters and variants in candidate genes in drug metabolism pathways (methyltransferases [thiopurine S-methyltransferase, TPMT] and [catechol-O-methyltransferase, COMT], and drug transporter ABCC3). PROCEDURE We retrospectively reviewed clinical records of patients with retinoblastoma treated with carboplatin chemotherapy regarding age (at diagnosis and chemotherapy initiation), chemotherapy sessions (cycles number, drug doses, and cumulative carboplatin dose), and hearing loss (defined as ototoxicity ≥grade 2 by at least one classification system). Blood samples were genotyped for genetic variants in TPMT (rs12201199, rs1800460), COMT (rs4646316, rs9332377), and ABCC3 (rs1051640) by quantitative PCR and confirmed by allele-specific PCR. Univariate statistical tests, receiver-operating characteristic analysis, and Kaplan-Meier curves were used to examine the association between hearing loss, clinical factors, and variants in candidate genes. RESULTS Audiometric data and stored DNA were available for 71 patients with retinoblastoma (88% carried an RB1 pathogenic variant allele). Median carboplatin cumulative dose was 1,400 mg/m2 (260-5,148 mg/m2 ). Ototoxicity occurred in 18 patients (25%), strongly associated with age at diagnosis (P = 0.01) and age at chemotherapy initiation (OR = 4.99, P = 0.008). The highest likelihood ratio of hearing loss was associated with chemotherapy initiation <4.25 months of age. Ototoxicity was not associated with any tested genetic variants. CONCLUSIONS We observed a 25% prevalence of ototoxicity in patients with retinoblastoma treated with carboplatin, higher than previously published. Age at chemotherapy initiation was associated with carboplatin-induced ototoxicity, with children <4.25 months of age at highest risk.
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Affiliation(s)
- Sameh E Soliman
- Faculty of Medicine, Department of Ophthalmology, University of Alexandria, Alexandria, Egypt.,Department of Ophthalmology and Vision Science, Hospital for Sick Children, Toronto, Canada
| | - Crystal N D'Silva
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Helen Dimaras
- Department of Ophthalmology and Vision Science, Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Canada.,Child Health Evaluative Sciences Program, SickKids Research Institute, Toronto, Canada.,Division of Clinical Public Health, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - Irakli Dzneladze
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Helen Chan
- Division of Haematology/Oncology, Hospital for Sick Children, Toronto, Canada
| | - Brenda L Gallie
- Department of Ophthalmology and Vision Science, Hospital for Sick Children, Toronto, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada.,Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Canada
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Contralateral Suppression of DPOAEs in Mice after Ouabain Treatment. Neural Plast 2018; 2018:6890613. [PMID: 29849563 PMCID: PMC5914095 DOI: 10.1155/2018/6890613] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/25/2018] [Accepted: 02/27/2018] [Indexed: 12/26/2022] Open
Abstract
Medial olivocochlear (MOC) efferent feedback is suggested to protect the ear from acoustic injury and to increase its ability to discriminate sounds against a noisy background. We investigated whether type II spiral ganglion neurons participate in the contralateral suppression of the MOC reflex. The application of ouabain to the round window of the mouse cochlea selectively induced the apoptosis of the type I spiral ganglion neurons, left the peripherin-immunopositive type II spiral ganglion neurons intact, and did not affect outer hairs, as evidenced by the maintenance of the distorted product otoacoustic emissions (DPOAEs). With the ouabain treatment, the threshold of the auditory brainstem response increased significantly and the amplitude of wave I decreased significantly in the ouabain-treated ears, consistent with the loss of type I neurons. Contralateral suppression was measured as reduction in the amplitude of the 2f1−f2 DPOAEs when noise was presented to the opposite ear. Despite the loss of all the type I spiral ganglion neurons, virtually, the amplitude of the contralateral suppression was not significantly different from the control when the suppressor noise was delivered to the treated cochlea. These results are consistent with the type II spiral ganglion neurons providing the sensory input driving contralateral suppression of the MOC reflex.
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Lourenço B, Madero B, Tringali S, Dubernard X, Khalil T, Chays A, Bazin A, Mom T, Avan P. Non-invasive intraoperative monitoring of cochlear function by cochlear microphonics during cerebellopontine-angle surgery. Eur Arch Otorhinolaryngol 2017; 275:59-69. [PMID: 29080147 DOI: 10.1007/s00405-017-4780-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 10/12/2017] [Indexed: 11/28/2022]
Abstract
In vestibular-schwannoma (VS) surgery, hearing-preservation rate remains low. Besides damage to the cochlear nerve, intraoperative cochlear ischemia is a potential cause of hearing loss. Here, we used non-invasive cochlear microphonic (CM) recordings to detect the cochlear vascular events of VS surgery. Continuous intraoperative CM monitoring, in response to 80-95 dB SPL, 1-kHz tone-bursts, was performed in two samples of patients undergoing retrosigmoid cerebellopontine-angle surgery: one for VS (n = 31) and one for vestibular neurectomy or vasculo-neural conflict causing intractable trigeminal neuralgia, harmless to hearing (n = 19, control group). Preoperative and postoperative hearings were compared as a function of intraoperative CM changes and their chronology. Monitoring was possible throughout except for a few tens of seconds when drilling or suction noises occurred. Four patterns of CM time course were identified, eventless, fluctuating, abrupt or progressive decrease. Only the VS group displayed the last two patterns, mainly during internal-auditory-canal drilling and the ensuing tumor dissection, always with postoperative loss of hearing as an end result. Conversely, eventless and fluctuating CM patterns could be associated with postoperative hearing loss when the cochlear nerve had been reportedly damaged, an event that CM is not meant to detect. Cochlear ischemia is a frequent event in VS surgery that leads to deafness. The findings that CM decrease raised no false alarm, and that CM fluctuations, insignificant in control cases, were easily spotted, suggest that CM intraoperative monitoring is a sensitive tool that could profitably guide VS surgery.
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Affiliation(s)
- Blandine Lourenço
- INSERM, Laboratory of Neurosensory Biophysics, Université Clermont Auvergne, 63000, Clermont-Ferrand, France.,Department of Otolaryngology Head Neck Surgery, University Hospital, Clermont-Ferrand, France.,Centre Jean Perrin, Clermont-Ferrand, France
| | - Béatriz Madero
- INSERM, Laboratory of Neurosensory Biophysics, Université Clermont Auvergne, 63000, Clermont-Ferrand, France.,Department of Otolaryngology Head Neck Surgery, University Hospital, Reims, France.,Centre Jean Perrin, Clermont-Ferrand, France
| | - Stéphane Tringali
- Department of Otolaryngology Head Neck Surgery, University Hospital, Lyon, France
| | - Xavier Dubernard
- Department of Otolaryngology Head Neck Surgery, University Hospital, Reims, France
| | - Toufic Khalil
- Department of Neurosurgery, University Hospital, Clermont-Ferrand, France
| | - André Chays
- Department of Otolaryngology Head Neck Surgery, University Hospital, Reims, France
| | - Arnaud Bazin
- Department of Neurosurgery, University Hospital, Reims, France
| | - Thierry Mom
- INSERM, Laboratory of Neurosensory Biophysics, Université Clermont Auvergne, 63000, Clermont-Ferrand, France.,Department of Otolaryngology Head Neck Surgery, University Hospital, Clermont-Ferrand, France
| | - Paul Avan
- INSERM, Laboratory of Neurosensory Biophysics, Université Clermont Auvergne, 63000, Clermont-Ferrand, France. .,Centre Jean Perrin, Clermont-Ferrand, France.
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Burwood GWS, Russell IJ, Lukashkin AN. Rippling pattern of distortion product otoacoustic emissions evoked by high-frequency primaries in guinea pigs. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:855. [PMID: 28863551 DOI: 10.1121/1.4998584] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The origin of ripples in distortion product otoacoustic emission (DPOAE) amplitude which appear at specific DPOAE frequencies during f1 tone sweeps using fixed high frequency f2 (>20 kHz) in guinea pigs is investigated. The peaks of the ripples, or local DPOAE amplitude maxima, are separated by approximately half octave intervals and are accompanied by phase oscillations. The local maxima appear at the same frequencies in DPOAEs of different order and velocity responses of the stapes and do not shift with increasing levels of the primaries. A suppressor tone had little effect on the frequencies of the maxima, but partially suppressed DPOAE amplitude when it was placed close to the f2 frequencies. These findings agree with earlier observations that the maxima occur at the same DPOAE frequencies, which are independent of the f2 and the primary ratio, and thus are likely to be associated with DPOAE propagation mechanisms. Furthermore, the separation of the local maxima by approximately half an octave may suggest that the maxima are due to interference of the travelling waves along the basilar membrane at the frequency of the DPOAE. It is suggested that the rippling pattern appears because of interaction between DPOAE reverse travelling waves with standing waves formed in the cochlea.
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Affiliation(s)
- George W S Burwood
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, United Kingdom
| | - Ian J Russell
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, United Kingdom
| | - Andrei N Lukashkin
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, United Kingdom
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Race N, Lai J, Shi R, Bartlett EL. Differences in postinjury auditory system pathophysiology after mild blast and nonblast acute acoustic trauma. J Neurophysiol 2017; 118:782-799. [PMID: 28275059 PMCID: PMC5539456 DOI: 10.1152/jn.00710.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 01/05/2023] Open
Abstract
Hearing difficulties are the most commonly reported disabilities among veterans. Blast exposures during explosive events likely play a role, given their propensity to directly damage both peripheral (PAS) and central auditory system (CAS) components. Postblast PAS pathophysiology has been well documented in both clinical case reports and laboratory investigations. In contrast, blast-induced CAS dysfunction remains understudied but has been hypothesized to contribute to an array of common veteran behavioral complaints, including learning, memory, communication, and emotional regulation. This investigation compared the effects of acute blast and nonblast acoustic impulse trauma in adult male Sprague-Dawley rats. An array of audiometric tests were utilized, including distortion product otoacoustic emissions (DPOAE), auditory brain stem responses (ABR), middle latency responses (MLR), and envelope following responses (EFRs). Generally, more severe and persistent postinjury central auditory processing (CAP) deficits were observed in blast-exposed animals throughout the auditory neuraxis, spanning from the cochlea to the cortex. DPOAE and ABR results captured cochlear and auditory nerve/brain stem deficits, respectively. EFRs demonstrated temporal processing impairments suggestive of functional damage to regions in the auditory brain stem and the inferior colliculus. MLRs captured thalamocortical transmission and cortical activation impairments. Taken together, the results suggest blast-induced CAS dysfunction may play a complementary pathophysiological role to maladaptive neuroplasticity of PAS origin. Even mild blasts can produce lasting hearing impairments that can be assessed with noninvasive electrophysiology, allowing these measurements to serve as simple, effective diagnostics.NEW & NOTEWORTHY Blasts exposures often produce hearing difficulties. Although cochlear damage typically occurs, the downstream effects on central auditory processing are less clear. Moreover, outcomes were compared between individuals exposed to the blast pressure wave vs. those who experienced the blast noise without the pressure wave. It was found that a single blast exposure produced changes at all stages of the ascending auditory path at least 4 wk postblast, whereas blast noise alone produced largely transient changes.
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Affiliation(s)
- Nicholas Race
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
- School of Medicine, Indiana University, Indianapolis, Indiana
| | - Jesyin Lai
- Purdue University Inderdisciplinary Life Science (PULSe) Program, Purdue University, West Lafayette, Indiana; and
| | - Riyi Shi
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
- Purdue University Inderdisciplinary Life Science (PULSe) Program, Purdue University, West Lafayette, Indiana; and
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana
| | - Edward L Bartlett
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana;
- Purdue University Inderdisciplinary Life Science (PULSe) Program, Purdue University, West Lafayette, Indiana; and
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Auditory cortex interneuron development requires cadherins operating hair-cell mechanoelectrical transduction. Proc Natl Acad Sci U S A 2017; 114:7765-7774. [PMID: 28705869 DOI: 10.1073/pnas.1703408114] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Many genetic forms of congenital deafness affect the sound reception antenna of cochlear sensory cells, the hair bundle. The resulting sensory deprivation jeopardizes auditory cortex (AC) maturation. Early prosthetic intervention should revive this process. Nevertheless, this view assumes that no intrinsic AC deficits coexist with the cochlear ones, a possibility as yet unexplored. We show here that many GABAergic interneurons, from their generation in the medial ganglionic eminence up to their settlement in the AC, express two cadherin-related (cdhr) proteins, cdhr23 and cdhr15, that form the hair bundle tip links gating the mechanoelectrical transduction channels. Mutant mice lacking either protein showed a major decrease in the number of parvalbumin interneurons specifically in the AC, and displayed audiogenic reflex seizures. Cdhr15- and Cdhr23-expressing interneuron precursors in Cdhr23-/- and Cdhr15-/- mouse embryos, respectively, failed to enter the embryonic cortex and were scattered throughout the subpallium, consistent with the cell polarity abnormalities we observed in vitro. In the absence of adhesion G protein-coupled receptor V1 (adgrv1), another hair bundle link protein, the entry of Cdhr23- and Cdhr15-expressing interneuron precursors into the embryonic cortex was also impaired. Our results demonstrate that a population of newborn interneurons is endowed with specific cdhr proteins necessary for these cells to reach the developing AC. We suggest that an "early adhesion code" targets populations of interneuron precursors to restricted neocortical regions belonging to the same functional area. These findings open up new perspectives for auditory rehabilitation and cortical therapies in patients.
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Zelle D, Lorenz L, Thiericke JP, Gummer AW, Dalhoff E. Input-output functions of the nonlinear-distortion component of distortion-product otoacoustic emissions in normal and hearing-impaired human ears. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 141:3203. [PMID: 28599560 PMCID: PMC5426960 DOI: 10.1121/1.4982923] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Distortion-product otoacoustic emissions (DPOAEs) arise in the cochlea in response to two tones with frequencies f1 and f2 and mainly consist of two components, a nonlinear-distortion and a coherent-reflection component. Wave interference between these components limits the accuracy of DPOAEs when evaluating the function of the cochlea with conventional continuous stimulus tones. Here, DPOAE components are separated in the time domain from DPOAE signals elicited with short stimulus pulses. The extracted nonlinear-distortion components are used to derive estimated distortion-product thresholds (EDPTs) from semi-logarithmic input-output (I/O) functions for 20 normal-hearing and 21 hearing-impaired subjects. I/O functions were measured with frequency-specific stimulus levels at eight frequencies f2 = 1,…, 8 kHz (f2/f1 = 1.2). For comparison, DPOAEs were also elicited with continuous primary tones. Both acquisition paradigms yielded EDPTs, which significantly correlated with behavioral thresholds (p < 0.001) and enabled derivation of estimated hearing thresholds (EHTs) from EDPTs using a linear regression relationship. DPOAE-component separation in the time domain significantly reduced the standard deviation of EHTs compared to that derived from continuous DPOAEs (p < 0.01). In conclusion, using frequency-specific stimulus levels and DPOAE-component separation increases the reliability of DPOAE I/O functions for assessing cochlear function and estimating behavioral thresholds.
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Affiliation(s)
- Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Lisa Lorenz
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - John P Thiericke
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
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Giraudet F, Longeras F, Mulliez A, Thalamy A, Pereira B, Avan P, Sakka L. Noninvasive detection of alarming intracranial pressure changes by auditory monitoring in early management of brain injury: a prospective invasive versus noninvasive study. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2017; 21:35. [PMID: 28219399 PMCID: PMC5319090 DOI: 10.1186/s13054-017-1616-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/24/2017] [Indexed: 11/10/2022]
Abstract
BACKGROUND In brain-injured patients intracranial pressure (ICP) is monitored invasively by a ventricular or intraparenchymal transducer. The procedure requires specific expertise and exposes the patient to complications such as malposition, hemorrhage or infection. As inner-ear fluid compartments are connected to the cerebrospinal fluid space, ICP changes elicit subtle changes in the physiology of the inner ear. Notably, we previously demonstrated that the phase of cochlear microphonic potential (CM) generated by sound stimuli rotates with ICP. The aim of our study was to validate the monitoring of CM as a noninvasive method to follow ICP. METHODS Non-invasive measure of CM-phase was compared to ICP recorded invasively in a prospective series of patients with acute brain injury managed in a neuro-intensive care unit. The study focused on patients with varying ICP and normal middle-ear function. RESULTS In the 24 patients with less than 4 days of endotracheal ventilation and whose ICP fluctuated (50-hour data), we demonstrated close correlation between CM-phase rotation and ICP (average 1.26 degrees/mmHg). As a binary classifier, CM phase changes of 7-10 degrees signaled 7.5-mmHg ICP increases with a sensitivity of 83% and 19% fallout. CONCLUSION Reference methods to measure ICP require the surgical placement of a pressure transducer. Noninvasive CM-based monitoring of ICP might be beneficial to early management of brain-injured patients with initially preserved consciousness and to the diagnosis of neurological conditions, whenever invasive monitoring cannot be performed. TRIAL REGISTRATION ClinicalTrials.gov NCT01685476 , registered on 30 August 2012.
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Affiliation(s)
- Fabrice Giraudet
- University Clermont Auvergne, Laboratory of Neurosensory Biophysics, UMR INSERM 1107, Clermont-Ferrand, France
| | - François Longeras
- Department of Anesthesiology and Intensive Care, University Hospital, rue Montalembert, Clermont-Ferrand, 63000, France
| | - Aurélien Mulliez
- Department of Biostatistics, University Hospital, PO Box 69, Clermont-Ferrand, 63003, France
| | - Aurélie Thalamy
- Department of Clinical Research and Innovation, University Hospital, PO Box 69, Clermont-Ferrand, 63003, France
| | - Bruno Pereira
- Department of Biostatistics, University Hospital, PO Box 69, Clermont-Ferrand, 63003, France
| | - Paul Avan
- University Clermont Auvergne, Laboratory of Neurosensory Biophysics, UMR INSERM 1107, Clermont-Ferrand, France. .,Centre Jean Perrin, 30 rue Montalembert, Clermont-Ferrand, 63000, France. .,School of Medicine, 28 Place Henri Dunant, Clermont-Ferrand, 63000, France.
| | - Laurent Sakka
- University Clermont Auvergne, Laboratory of Neurosensory Biophysics, UMR INSERM 1107, Clermont-Ferrand, France
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Dong W. Simultaneous Intracochlear Pressure Measurements from Two Cochlear Locations: Propagation of Distortion Products in Gerbil. J Assoc Res Otolaryngol 2016; 18:209-225. [PMID: 27909837 DOI: 10.1007/s10162-016-0602-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 10/31/2016] [Indexed: 11/30/2022] Open
Abstract
Sound energy propagates in the cochlea through a forward-traveling or slow wave supported by the cochlear partition and fluid inertia. Additionally, cochlear models support traveling wave propagation in the reverse direction as the expected mechanism for conveying otoacoustic emissions out of the cochlea. Recently, however, this hypothesis has been questioned, casting doubt on the process by which otoacoustic emissions travel back out through the cochlea. The proposed alternative reverse travel path for emissions is directly through the fluids of the cochlea as a compression pressure in the form of a fast wave. In the present study, a custom-made micro-pressure sensor was used in vivo in the gerbil cochlea to map two-tone-evoked pressure responses at distinct longitudinal and vertical locations in both the scala tympani and scala vestibuli. Analyses of the magnitude and phase of intracochlear pressure responses at the primary tone and distortion product frequencies were used to distinguish between fast and slow waves in both the forward- and reverse-propagation directions. Results demonstrated that distortion products may travel in both forward and reverse directions post-generation and the existence of both traveling and compression waves. The forward-traveling component appeared to duplicate the process of any external tone, tuned to the local characteristic-frequency place, as it increased compressively and nonlinearly with primary-tone levels. A compression wave was evidenced at frequencies above the cutoff of the recording site. In the opposite direction, a reverse-traveling wave played the major role in driving the stapes reversely and contributed to the distortion product otoacoustic emission. The compression wave may also play a role in reverse propagation when distortion products are generated at a region close to the stapes.
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Affiliation(s)
- Wei Dong
- Research Service (151), VA Loma Linda Healthcare System, 11201 Benton St, Loma Linda, CA, 92357, USA. .,Department of Otolaryngology--Head & Neck Surgery, Loma Linda University Health, 11234 Anderson St, Loma Linda, CA, 92354, USA.
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Comparing Distortion Product Otoacoustic Emissions to Intracochlear Distortion Products Inferred from a Noninvasive Assay. J Assoc Res Otolaryngol 2016; 17:271-87. [PMID: 27229002 DOI: 10.1007/s10162-016-0552-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 01/12/2016] [Indexed: 10/21/2022] Open
Abstract
The behavior of intracochlear distortion products (iDPs) was inferred by interacting a probe tone (f3) with the iDP of interest to produce a "secondary" distortion product otoacoustic emission termed DPOAE(2ry). Measures of the DPOAE(2ry) were then used to deduce the properties of the iDP. This approach was used in alert rabbits and anesthetized gerbils to compare ear-canal 2f1-f2 and 2f2-f1 DPOAE f2/f1 ratio functions, level/phase (L/P) maps, and interference-response areas (IRAs) to their simultaneously collected DPOAE(2ry) counterparts. These same measures were also collected in a human volunteer to demonstrate similarities with their laboratory animal counterparts and their potential applicability to humans. Results showed that DPOAEs and inferred iDPs evidenced distinct behaviors and properties. That is, DPOAE ratio functions elicited by low-level primaries peaked around an f2/f1 = 1.21 or 1.25, depending on species, while the corresponding inferred iDP ratio functions peaked at f2/f1 ratios of ~1. Additionally, L/P maps showed rapid phase variation with DPOAE frequency (fdp) for the narrow-ratio 2f1-f2 and all 2f2-f1 DPOAEs, while the corresponding DPOAE(2ry) measures evidenced relatively constant phases. Common features of narrow-ratio DPOAE IRAs, such as large enhancements for interference tones (ITs) presented above f2, were not present in DPOAE(2ry) IRAs. Finally, based on prior experiments in gerbils, the behavior of the iDP directly measured in intracochlear pressure was compared to the iDP inferred from the DPOAE(2ry) and found to be similar. Together, these findings are consistent with the notion that under certain conditions, ear-canal DPOAEs provide poor representations of iDPs and thus support a "beamforming" hypothesis. According to this concept, distributed emission components directed toward the ear canal from the f2 and basal to f2 regions can be of differing phases and thus cancel, while these same components directed toward fdp add in phase.
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Sakka L, Chomicki A, Gabrillargues J, Khalil T, Chazal J, Avan P. Validation of a noninvasive test routinely used in otology for the diagnosis of cerebrospinal fluid shunt malfunction in patients with normal pressure hydrocephalus. J Neurosurg 2016; 124:342-9. [DOI: 10.3171/2015.1.jns142142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
Ventriculoperitoneal shunting is the first-line treatment for normal pressure hydrocephalus. Noninvasive auditory tests based on recorded otoacoustic emissions were assessed, as currently used for universal neonatal hearing screenings, for the diagnosis of cerebrospinal fluid shunt malfunction. The test was designed based on previous works, which demonstrated that an intracranial pressure change induces a proportional, characteristic, otoacoustic-emission phase shift.
METHODS
Forty-four patients with normal pressure hydrocephalus (23 idiopathic and 21 secondary cases) were included in this prospective observational study. The male:female sex ratio was 1.44, the age range was 21–87 years (mean age 64.3 years), and the range of the follow-up period was 1–3 years (mean 20 months). Patients were implanted with a Sophy SU8 adjustable-pressure valve as the ventriculoperitoneal shunt. The phase shifts of otoacoustic emissions in response to body tilt were measured preoperatively, immediately postoperatively, and at 3–6 months, 7–15 months, 16–24 months, and more than 24 months postoperatively. Three groups were enrolled: Group 1, 19 patients who required no valve opening-pressure adjustment; Group 2, 18 patients who required valve opening-pressure adjustments; and Group 3, 7 patients who required valve replacement.
RESULTS
In Group 1, phase shift, which was positive before surgery, became steadily negative after surgery and during the follow-up. In Group 2, phase shift, which was positive before surgery, became negative immediately after surgery and increasingly negative after a decrease in the valve-opening pressure. In Group 3, phase shift was positive in 6 cases and slightly negative in 1 case before revision, but after revision phase shift became significantly negative in all cases.
CONCLUSIONS
Otoacoustic emissions noninvasively reflect cerebrospinal fluid shunt function and are impacted by valve-opening pressure adjustments. Otoacoustic emissions consistently diagnosed shunt malfunction and predicted the need for surgical revision. The authors’ diagnostic test, which can be repeated without risk or discomfort by an unskilled operator, may address the crucial need of detecting valve dysfunction in patients with poor clinical outcome after shunt surgery.
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Affiliation(s)
- Laurent Sakka
- 1Service de Neurochirurgie, Hôpital Gabriel Montpied, Centre Hospitalier Universitaire de Clermont-Ferrand
- 2Equipe IGCNC, EA 7282, ISIT, UMR 6284, CNRS, Université d’Auvergne
| | - Alexandre Chomicki
- 4Laboratoire de Biophysique Sensorielle, Faculté de Médecine, Université d’Auvergne; and
| | - Jean Gabrillargues
- 3Service de Neuroradiologie, Hôpital Gabriel Montpied, Centre Hospitalier Universitaire de Clermont-Ferrand
| | - Toufic Khalil
- 1Service de Neurochirurgie, Hôpital Gabriel Montpied, Centre Hospitalier Universitaire de Clermont-Ferrand
- 2Equipe IGCNC, EA 7282, ISIT, UMR 6284, CNRS, Université d’Auvergne
| | - Jean Chazal
- 1Service de Neurochirurgie, Hôpital Gabriel Montpied, Centre Hospitalier Universitaire de Clermont-Ferrand
- 2Equipe IGCNC, EA 7282, ISIT, UMR 6284, CNRS, Université d’Auvergne
| | - Paul Avan
- 4Laboratoire de Biophysique Sensorielle, Faculté de Médecine, Université d’Auvergne; and
- 5Biophysique Médicale, Centre Jean Perrin, Clermont-Ferrand, France
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