Transient Abnormalities in Masking Tuning Curve in Early Progressive Hearing Loss Mouse Model

Damage to cochlear outer hair cells (OHCs) usually affects frequency selectivity in proportion to hearing threshold increase. However, the current clinical heuristics that attributes poor hearing performance despite near-normal auditory sensitivity to auditory neuropathy or “hidden” synaptopathy overlooks possible underlying OHC impairment. Here, we document the part played by OHCs in influencing suprathreshold auditory performance in the presence of noise in a mouse model of progressive hair cell degeneration, the CD1 strain, at postnatal day 18–30 stages when high-frequency auditory thresholds remained near-normal. Nonetheless, total loss of high-frequency distortion product otoacoustic emissions pointed to nonfunctioning basal OHCs. This “discordant profile” came with a huge low-frequency shift of masking tuning curves that plot the level of interfering sound necessary to mask the response to a probe tone, against interfering frequency. Histology revealed intense OHC hair bundle abnormalities in the basal cochlea uncharacteristically associated with OHC survival and preserved coupling with the tectorial membrane. This pattern dismisses the superficial diagnosis of “hidden” neuropathy while underpinning a disorganization of cochlear frequency mapping with optimistic high-frequency auditory thresholds perhaps because responses to high frequencies are apically shifted. The audiometric advantage of frequency transposition is offset by enhanced masking by low-frequency sounds, a finding essential for guiding rehabilitation.

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High Frequency of AIFM1 Variants and Phenotype Progression of Auditory Neuropathy in a Chinese Population

Neural Plasticity ◽

10.1155/2020/5625768 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Hongyang Wang ◽

Dan Bing ◽

Jin Li ◽

Linyi Xie ◽

Fen Xiong ◽

...

Keyword(s):

High Frequency ◽

Late Onset ◽

Hearing Threshold ◽

Low Frequency ◽

Auditory Neuropathy ◽

Recessive Inheritance ◽

Speech Discrimination ◽

Inheritance Pattern ◽

Dominant Inheritance

To decipher the genotype-phenotype correlation of auditory neuropathy (AN) caused by AIFM1 variations, as well as the phenotype progression of these patients, exploring the potential molecular pathogenic mechanism of AN. A total of 36 families of individuals with AN (50 cases) with AIFM1 variations were recruited and identified by Sanger sequencing or next-generation sequencing; the participants included 30 patients from 16 reported families and 20 new cases. We found that AIFM1-positive cases accounted for 18.6% of late-onset AN cases. Of the 50 AN patients with AIFM1 variants, 45 were male and 5 were female. The hotspot variation of this gene was p.Leu344Phe, accounting for 36.1%. A total of 19 AIFM1 variants were reported in this study, including 7 novel ones. A follow-up study was performed on 30 previously reported AIFM1-positive subjects, 16 follow-up cases (53.3%) were included in this study, and follow-up periods were recorded from 1 to 23 years with average 9.75±9.89 years. There was no hearing threshold increase during the short-term follow-up period (1-10 years), but the low-frequency and high-frequency hearing thresholds showed a significant increase with the prolongation of follow-up time. The speech discrimination score progressed gradually and significantly along with the course of the disease and showed a more serious decline, which was disproportionately worse than the pure tone threshold. In addition to the X-linked recessive inheritance pattern, the X-linked dominant inheritance pattern is also observed in AIFM1-related AN and affects females. In conclusion, we confirmed that AIFM1 is the primary related gene among late-onset AN cases, and the most common recurrent variant is p.Leu344Phe. Except for the X-linked recessive inheritance pattern, the X-linked dominant inheritance pattern is another probability of AIFM1-related AN, with females affected. Phenotypical features of AIFM1-related AN suggested that auditory dyssynchrony progressively worsened over time.

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Hearing Thresholds Changes after MRI 1.5T of Head and Neck

Radiology Research and Practice ◽

10.1155/2019/8756579 ◽

2019 ◽

Vol 2019 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

Maryam Bahaloo ◽

Mohammad Hossein Davari ◽

Mohammad Sobhan ◽

Seyyed Jalil Mirmohammadi ◽

Mohammad Taghi Jalalian ◽

...

Keyword(s):

Head And Neck ◽

High Frequency ◽

Repeated Measures ◽

Hearing Threshold ◽

Significant Shift ◽

Auditory Thresholds ◽

Hearing Thresholds ◽

High Frequency Audiometry ◽

Significant Difference ◽

Before And After

Introduction. Exposure to high intensity noise produced by MRI is a cause for concern. This study was conducted to determine the temporary and permanent effects of exposure to noise created by performing MRI on the hearing threshold of the subjects using conventional and extended high frequency audiometry. Methods. This semiexperimental study was performed on 35 patients referred to Shahid Rahnemoun Hospital for head and neck MRI due to different clinical conditions. The hearing threshold of patients was measured before, immediately after, and 24 hours after performing 1.5 Tesla MRI using conventional and extended high frequency audiometry. SPSS version 18 was used to compare the mean hearing thresholds before and after MRI using paired T test and repeated measures analysis. Results. Comparison of auditory thresholds in conventional and extended high frequencies before and immediately after MRI showed a significant shift at 4 KHz (P = 0.008 and P = 0.08 for right and left ears), 6 KHz (P = 0.03 and P = 0.01 for right and left ears), and 14 KHz (P =0.03 and P = 0.31 for right and left ears). However, there was no significant difference between audiometric thresholds before and 24 hours after MRI. Conclusion. Noise due to 1.5 Tesla MRI can only cause transient threshold shift.

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The ultrastructural distribution of prestin in outer hair cells: a post-embedding immunogold investigation of low-frequency and high-frequency regions of the rat cochlea

European Journal of Neuroscience ◽

10.1111/j.1460-9568.2010.07182.x ◽

2010 ◽

Vol 31 (9) ◽

pp. 1595-1605 ◽

Cited By ~ 29

Author(s):

Shanthini Mahendrasingam ◽

Maryline Beurg ◽

Robert Fettiplace ◽

Carole M. Hackney

Keyword(s):

Hair Cells ◽

High Frequency ◽

Low Frequency ◽

Outer Hair Cells ◽

Rat Cochlea

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Prestin Expression in Cochlea of Bats Using Different Echolocation Systems

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.620.248 ◽

2014 ◽

Vol 620 ◽

pp. 248-252

Author(s):

Qi Jiu Li ◽

Xian De Zhang ◽

Ting Ting Xu ◽

Jiang Xia Yin

Keyword(s):

Hair Cells ◽

High Frequency ◽

Low Frequency ◽

Motor Protein ◽

Outer Hair Cells ◽

Intracellular Potential ◽

First Time ◽

Unique Ability

Outer hair cells (OHCs) have a unique ability to contract and elongate in response to changes in intracellular potential, and Prestin is the motor protein of the cochlea of the OHCs. It is the first time to invest the Prestin expression in different bat species. To invest Prestin expression in different bat species, which have different frequency, we did the coronal sections’ staining of the cochlea using immunhistochemistry. Experiment was designed to determine if the high-frequency bats’ OHCs have more expression than the low-frequency bats’OHCs. We found that the expression in three species was similar and had no obvious difference. Though the study of bats Prestin evolution suggested that Prestin has accelerating evolution in echolocation bats with high frequency, our we showed that the Prestin expression has nothing to do with the frequency, and the Prestin expression in high-frequency bats and low-frequency bats is similar.

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Role of the Tectorial Membrane Revealed by Otoacoustic Emissions Recorded From Wild-Type and Transgenic TectaΔENT/ΔENT Mice

Journal of Neurophysiology ◽

10.1152/jn.00680.2003 ◽

2004 ◽

Vol 91 (1) ◽

pp. 163-171 ◽

Cited By ~ 22

Author(s):

Andrei N. Lukashkin ◽

Victoria A. Lukashkina ◽

P. Kevin Legan ◽

Guy P. Richardson ◽

Ian J. Russell

Keyword(s):

Otoacoustic Emissions ◽

Low Frequency ◽

Tectorial Membrane ◽

Local Minima ◽

Wild Type ◽

Distortion Product ◽

Growth Functions ◽

In The Wild ◽

Surrounding Fluid

Distortion product otoacoustic emissions (DPOAE) were recorded from wild-type mice and mutant TectaΔ ENT/Δ ENT mice with detached tectorial membranes (TM) under combined ketamine/xylaxine anesthesia. In TectaΔ ENT/Δ ENT mice, DPOAEs could be detected above the noise floor only when the levels of the primary tones exceeded 65 dB SPL. DPOAE amplitude decreased with increasing frequency of the primaries in TectaΔ ENT/Δ ENT mice. This was attributed to hair cell excitation via viscous coupling to the surrounding fluid and not by interaction with the TM as in the wild-type mice. Local minima and corresponding phase transitions in the DPOAE growth functions occurred at higher DPOAE levels in wild-type than in TectaΔ ENT/Δ ENT mice. In less-sensitive TectaΔ ENT/Δ ENT mice, the position of the local minima varied nonsystematically with frequency or no minima were observed. A bell-like dependence of the DPOAE amplitude on the ratio of the primaries was recorded in both wild-type and TectaΔ ENT/Δ ENT mice. However, the pattern of this dependence was different in the wild-type and TectaΔ ENT/Δ ENT mice, an indication that the bell-like shape of the DPOAE was produced by a combination of different mechanisms. A nonlinear low-frequency resonance, revealed by nonmonotonicity of the phase behavior, was seen in the wild-type but not in TectaΔ ENT/Δ ENT mice.

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Minimal basilar membrane motion in low-frequency hearing

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1606317113 ◽

2016 ◽

Vol 113 (30) ◽

pp. E4304-E4310 ◽

Cited By ~ 24

Author(s):

Rebecca L. Warren ◽

Sripriya Ramamoorthy ◽

Nikola Ciganović ◽

Yuan Zhang ◽

Teresa M. Wilson ◽

...

Keyword(s):

High Frequency ◽

Music Perception ◽

Basilar Membrane ◽

Stimulus Frequency ◽

Low Frequency ◽

Laser Interferometry ◽

Outer Hair Cells ◽

Sound Stimulation

Low-frequency hearing is critically important for speech and music perception, but no mechanical measurements have previously been available from inner ears with intact low-frequency parts. These regions of the cochlea may function in ways different from the extensively studied high-frequency regions, where the sensory outer hair cells produce force that greatly increases the sound-evoked vibrations of the basilar membrane. We used laser interferometry in vitro and optical coherence tomography in vivo to study the low-frequency part of the guinea pig cochlea, and found that sound stimulation caused motion of a minimal portion of the basilar membrane. Outside the region of peak movement, an exponential decline in motion amplitude occurred across the basilar membrane. The moving region had different dependence on stimulus frequency than the vibrations measured near the mechanosensitive stereocilia. This behavior differs substantially from the behavior found in the extensively studied high-frequency regions of the cochlea.

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Beyond the limits: identifying the high-frequency detectors in the anuran ear

Biology Letters ◽

10.1098/rsbl.2020.0343 ◽

2020 ◽

Vol 16 (7) ◽

pp. 20200343

Author(s):

Ariadna Cobo-Cuan ◽

T. Ulmar Grafe ◽

Peter M. Narins

Keyword(s):

Inner Ear ◽

High Frequency ◽

Otoacoustic Emissions ◽

Sensory System ◽

Low Frequency ◽

Basilar Papilla ◽

High Frequency Ultrasound ◽

Ultrasonic Signals ◽

Distortion Product ◽

Frog Species

Despite the predominance of low-frequency hearing in anuran amphibians, a few frog species have evolved high-frequency communication within certain environmental contexts. Huia cavitympanum is the most remarkable anuran with regard to upper frequency limits; it is the first frog species known to emit exclusively ultrasonic signals. Characteristics of the Distortion Product Otoacoustic Emissions from the amphibian papilla and the basilar papilla were analysed to gain insight into the structures responsible for high-frequency/ultrasound sensitivity. Our results confirm the matching of vocalization spectra and inner ear tuning in this species. Compared to most anurans, H. cavitympanum has a hyperextended hearing range spanning from audible to ultrasonic frequencies, far above the previously established ‘spectral limits’ for the amphibian ear. The exceptional high-frequency sensitivity in the inner ear of H. cavitympanum illustrates the remarkable plasticity of the auditory system and the extent to which evolution can modify a sensory system to adapt it to its environment.

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Functional Parameters of Prestin Are Not Correlated With the Best Hearing Frequency

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.638530 ◽

2021 ◽

Vol 9 ◽

Author(s):

Zhongying Wang ◽

Qingping Ma ◽

Jiawen Lu ◽

Xiaochen Cui ◽

Haifeng Chen ◽

...

Keyword(s):

High Frequency ◽

Low Frequency ◽

Outer Hair Cells ◽

Amino Acid Sequences ◽

Striking Difference ◽

Functional Parameters ◽

Leading Role ◽

Frequency Detection ◽

Whole Cell Patch Clamp ◽

Voltage Dependent

Among the vertebrate lineages with different hearing frequency ranges, humans lie between the low-frequency hearing (1 kHz) of fish and amphibians and the high-frequency hearing (100 kHz) of bats and dolphins. Little is known about the mechanism underlying such a striking difference in the limits of hearing frequency. Prestin, responsible for cochlear amplification and frequency selectivity in mammals, seems to be the only candidate to date. Mammalian prestin is densely expressed in the lateral plasma membrane of the outer hair cells (OHCs) and functions as a voltage-dependent motor protein. To explore the molecular basis for the contribution of prestin in hearing frequency detection, we collected audiogram data from humans, dogs, gerbils, bats, and dolphins because their average hearing frequency rises in steps. We generated stable cell lines transfected with human, dog, gerbil, bat, and dolphin prestins (hPres, dPres, gPres, bPres, and nPres, respectively). The non-linear capacitance (NLC) of different prestins was measured using a whole-cell patch clamp. We found that the Qmax/Clin of bPres and nPres was significantly higher than that of humans. The V1/2 of hPres was more hyperpolarized than that of nPres. The z values of hPres and bPres were higher than that of nPres. We further analyzed the relationship between the high-frequency hearing limit (Fmax) and the functional parameters (V1/2, z, and Qmax/Clin) of NLC among five prestins. Interestingly, no significant correlation was found between the functional parameters and Fmax. Additionally, a comparative study showed that the amino acid sequences and tertiary structures of five prestins were quite similar. There might be a common fundamental mechanism driving the function of prestins. These findings call for a reconsideration of the leading role of prestin in hearing frequency perception. Other intriguing kinetics underlying the hearing frequency response of auditory organs might exist.

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