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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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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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Charaziak KK, Shera CA. Reflection-Source Emissions Evoked with Clicks and Frequency Sweeps: Comparisons Across Levels. J Assoc Res Otolaryngol 2021; 22:641-658. [PMID: 34606020 DOI: 10.1007/s10162-021-00813-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/22/2021] [Indexed: 02/07/2023] Open
Abstract
According to coherent reflection theory, otoacoustic emissions (OAE) evoked with clicks (clicked-evoked, CE) or tones (stimulus frequency, SF) originate via the same mechanism. We test this hypothesis in gerbils by investigating the similarity of CE- and SFOAEs across a wide range of stimulus levels. The results show that OAE transfer functions measured in response to clicks and sweeps have nearly equivalent time-frequency characteristics, particularly at low stimulus levels. At high stimulus levels, the two OAE types are more dissimilar, reflecting the different dynamic properties of the evoking stimulus. At mid to high stimulus levels, time-frequency analysis reveals contributions from at least two OAE source components of varying latencies. Interference between these components explains the emergence of strong spectral microstructure. Time-frequency filtering based on mean basilar-membrane (BM) group delays (τBM) shows that late-latency OAE components (latency ~ 1.6τBM) dominate at low stimulus intensities and exhibit highly compressive growth with increasing stimulus intensity. In contrast, early-latency OAE components (~ 0.7τBM) are small at low stimulus levels but can come to dominate the overall response at higher intensities. Although the properties of long-latency OAEs are consistent with an origin via coherent reflection near the peak of the traveling wave, the generation place and/or mechanisms responsible for the early-latency OAE components warrant further investigation. Because their delay remains in constant proportion to τBM across sound intensity, long-latency OAEs, whether evoked with tones or clicks, can be used to predict characteristics of cochlear processing, such as the sharpness of frequency tuning, even at high stimulus levels.
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Affiliation(s)
- Karolina K Charaziak
- Caruso Department of Otolaryngology, University of Southern California, Los Angeles, CA, USA.
| | - Christopher A Shera
- Caruso Department of Otolaryngology, University of Southern California, Los Angeles, CA, USA.,Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, USA
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Bowling T, Wen H, Meenderink SWF, Dong W, Meaud J. Intracochlear distortion products are broadly generated by outer hair cells but their contributions to otoacoustic emissions are spatially restricted. Sci Rep 2021; 11:13651. [PMID: 34211051 PMCID: PMC8249639 DOI: 10.1038/s41598-021-93099-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/14/2021] [Indexed: 02/06/2023] Open
Abstract
Detection of low-level sounds by the mammalian cochlea requires electromechanical feedback from outer hair cells (OHCs). This feedback arises due to the electromotile response of OHCs, which is driven by the modulation of their receptor potential caused by the stimulation of mechano-sensitive ion channels. Nonlinearity in these channels distorts impinging sounds, creating distortion-products that are detectable in the ear canal as distortion-product otoacoustic emissions (DPOAEs). Ongoing efforts aim to develop DPOAEs, which reflects the ear's health, into diagnostic tools for sensory hearing loss. These efforts are hampered by limited knowledge on the cochlear extent contributing to DPOAEs. Here, we report on intracochlear distortion products (IDPs) in OHC electrical responses and intracochlear fluid pressures. Experiments and simulations with a physiologically motivated cochlear model show that widely generated electrical IDPs lead to mechanical vibrations in a frequency-dependent manner. The local cochlear impedance restricts the region from which IDPs contribute to DPOAEs at low to moderate intensity, which suggests that DPOAEs may be used clinically to provide location-specific information about cochlear damage.
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Affiliation(s)
- Thomas Bowling
- grid.213917.f0000 0001 2097 4943GWW School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA USA
| | - Haiqi Wen
- grid.213917.f0000 0001 2097 4943GWW School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA USA
| | - Sebastiaan W. F. Meenderink
- grid.422066.40000 0001 2195 7301VA Loma Linda Healthcare System, Loma Linda, CA 92357 USA ,grid.429814.2Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA 92350 USA
| | - Wei Dong
- grid.422066.40000 0001 2195 7301VA Loma Linda Healthcare System, Loma Linda, CA 92357 USA ,grid.429814.2Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA 92350 USA
| | - Julien Meaud
- grid.213917.f0000 0001 2097 4943GWW School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, GA USA
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