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.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8249639 | PMC |
| http://dx.doi.org/10.1038/s41598-021-93099-7 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Frequency dependence and harmonic distortion of stapes displacement and intracochlear pressure in response to very high level sounds.
Hear Res
November 2024
Department of Otolaryngology, University of Colorado School of Medicine, University of Colorado Anschutz Medical Campus, 12631 E 17th Ave. MS B205, Aurora, CO 80045, USA; Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA.
Previous reports have suggested that intracochlear pressures (P) measured at the base of the cochlea increase directly proportionally with stapes displacement (D) in response to moderately high (<130 dB SPL) level sounds. Consistent with this assumption, we have reported that for low frequency sounds (<1 kHz), stapes displacement and intracochlear pressures increase linearly with sound pressure level (SPL) for moderately high levels (<130 dB SPL), but saturate at higher exposure levels (>130 dB SPL). However, the magnitudes of each response were found to be frequency dependent, thus the relationship between D and P may vary at higher frequencies or higher levels.
View Article and Find Full Text PDFElectrocochleography-Based Tonotopic Map: I. Place Coding of the Human Cochlea With Hearing Loss.
Ear Hear
December 2024
Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA.
Article Synopsis
- - The study aims to map the tonotopy (frequency organization) of the human cochlea in vivo using cochlear implant electrodes, addressing challenges of past research that relied on cadaver and animal models.
- - Fifty patients with hearing loss underwent cochlear implantation, where their responses to sound stimuli were recorded to analyze how sound intensity and an artificial "third window" influence the tonotopic map.
- - Results showed notable deviations from the expected Greenwood model in the frequency-position function, especially at higher sound levels, indicating complexities in how the cochlea processes sound intensity.
Similar Tuning of Distortion-Product Otoacoustic Emission Ratio Functions and Cochlear Vibrations in Mice.
AIP Conf Proc
February 2024
Caruso Department of Otolaryngology - Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA.
When elicited by two stimulus tones (at frequencies and , > ), the amplitudes of specific distortion-product otoacoustic emission (DPOAE) components exhibit a characteristic bandpass shape as the ratio between and 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.
View Article and Find Full Text PDFClassification of Acoustic Hearing Preservation After Cochlear Implantation Using Electrocochleography.
Trends Hear
December 2023
Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
The objective to preserve residual hearing during cochlear implantation has recently led to the use of intracochlear electrocochleography (ECochG) as an intraoperative monitoring tool. Currently, a decrease in the amplitude of the difference between responses to alternating-polarity stimuli (DIF response), predominantly reflecting the hair cell response, is used for providing feedback. Including other ECochG response components, such as phase changes and harmonic distortions, could improve the accuracy of surgical feedback.
View Article and Find Full Text PDFUsing x-ray micro computed tomography to quantify intracochlear fibrosis after cochlear implantation in a Guinea pig model.
Heliyon
September 2023
Institute for Respiratory Health, University of Western Australia, Nedlands, WA 6009, Australia.
Cochlear implants (CIs) allow individuals with profound hearing loss to understand speech and perceive sounds. However, not all patients obtain the full benefits that CIs can provide and the cause of this disparity is not fully understood. One possible factor for the variability in outcomes after cochlear implantation, is the development of fibrotic scar tissue around the implanted electrode.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!