scholarly journals Outer Hair Cell Function is Normal in βV Spectrin Knockout Mice

2021 ◽  
Author(s):  
Michael C. Stankewich ◽  
Jun-Ping Bai ◽  
Paul R. Stabach ◽  
Saaim Khan ◽  
Lei Song ◽  
...  
Keyword(s):  
Hair Cell ◽  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Cell Function ◽  
Auditory Brainstem ◽  
Nerve Fibers ◽  
Outer Hair Cells ◽  
Neuronal Structure ◽  
Efferent Nerve ◽  
Brainstem Response

ABSTRACTReports have proposed a putative role for βV spectrin in outer hair cells (OHCs) of the cochlea. In an ongoing investigation of the role of the cytoskeleton in electromotility, we tested mice with a targeted exon deletion of βV spectrin (Spnb5), and unexpectedly find that Spnb5(-/-) animals’ auditory thresholds are unaffected. Similarly, these mice have normal OHC electromechanical activity (otoacoustic emissions) and non-linear capacitance. Moreover, Spnb5 mRNA is undetectable in the organ of Corti or OHCs. In contrast, magnitudes of auditory brainstem response (ABR) peak 1-amplitudes are significantly reduced. Evidence of a synaptopathy was absent with normal hair cell CtBP-2 counts. In Spnb5(-/-) mice, the number of afferent and efferent nerve fibers is decreased. Taken together, these data establish that βV spectrin is important for hearing, affecting neuronal structure and function. Significantly, these data exclude βV spectrin as functionally important to OHCs as has been previously suggested.

scholarly journals Auditory Brainstem Response Altered in Humans With Noise Exposure Despite Normal Outer Hair Cell Function

2017 ◽  
Vol 38 (1) ◽  
pp. e1-e12 ◽  
Author(s):  
Naomi F. Bramhall ◽  
Dawn Konrad-Martin ◽  
Garnett P. McMillan ◽  
Susan E. Griest
Keyword(s):  
Hair Cell ◽  
Auditory Brainstem Response ◽  
Noise Exposure ◽  
Outer Hair Cell ◽  
Cell Function ◽  
Auditory Brainstem ◽  
Brainstem Response

Acquired auditory neuropathy spectrum disorder after malaria treated with quinine

2020 ◽  
Vol 50 (3) ◽  
pp. 246-248
Author(s):  
Helen Brough
Keyword(s):  
Auditory Nerve ◽  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Cell Function ◽  
Auditory Brainstem ◽  
Auditory Neuropathy ◽  
Spectrum Disorder ◽  
Auditory Neuropathy Spectrum Disorder ◽  
Acoustic Reflexes ◽  
Brainstem Response

Auditory neuropathy spectrum disorder (ANSD) can cause significant hearing impairment; it occurs when there is intact outer hair cell function in the inner ear, with a dyssynchronous neural response, thought to be due to dysfunction of the inner hair cells (IHCs), the synapse of the IHCs and the auditory nerve, or of the auditory nerve itself. This case report describes the onset of ANSD in a Malawian child after severe malaria treated with quinine. Diagnosis of ANSD was made by confirming the presence of otoacoustic emissions, together with the absence of auditory brainstem response and absent acoustic reflexes.

DPOAE-Grams in Patients with Acute Tonal Tinnitus

2005 ◽  
Vol 132 (4) ◽  
pp. 550-553 ◽  
Author(s):  
Haralampos Gouveris ◽  
Jan Maurer ◽  
Wolf Mann
Keyword(s):  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Cell Function ◽  
Hearing Threshold ◽  
Normal Hearing ◽  
Outer Hair Cells ◽  
Controlled Study ◽  
High Frequency Region ◽  
Mean Values ◽  
Distortion Products

OBJECTIVE: To investigate cochlear outer hair cell function in patients with acute tonal tinnitus and normal or near-normal hearing threshold. STUDY DESIGN AND SETTING: Prospective controlled study in an academic tertiary health center. Distortion products of otoacoustic emissions (DPOAE)-grams of 32 ears with acute tonal tinnitus and normal hearing or minimal hearing loss were compared with those of 17 healthy nontinnitus ears. RESULTS: Tinnitus ears exhibited relatively increased amplitudes of DPOAE at high frequencies (4-6.3 kHz) when compared with the group of healthy ears and relatively decreased DPOAE amplitudes at middle frequencies (1650-2400 Hz). Statistically significant ( P < 0.01) increased mean values of DPOAE amplitudes were observed only at a frequency of f2 equal to 4.9 kHz. CONCLUSIONS AND SIGNIFICANCE: These findings suggest an altered functional state of the outer hair cells at a selected high-frequency region of the cochlea in ears with acute tonal tinnitus and normal or near-normal hearing threshold.

Early Evidence of Cochlear Damage in a Large Sample of Percussionists

2005 ◽  
Vol 20 (3) ◽  
pp. 135-139
Author(s):  
Jodee A Pride ◽  
David R Cunningham
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Cell Damage ◽  
Normal Hearing ◽  
Outer Hair Cells ◽  
Sensory Loss ◽  
Distortion Product ◽  
Hair Cell Damage

Percussionists can be exposed to intermittent sound stimuli that exceed 145 dB SPL, although damage may occur to the outer hair cells at levels of 120 dB SPL. The present study measured distortion-product otoacoustic emissions (DPOAEs) in a group of 86 normal-hearing percussionists and 39 normal-hearing nonpercussionists. Results indicate that normal-hearing percussionists have lower DPOAE amplitudes than normal-hearing nonpercussionists. DPOAE amplitudes were significantly lower at 6000 Hz in both the left and right ears for percussionists. Percussionists also more frequently had absent DPOAEs, with the greatest differences occurring at 6000 Hz (absent DPOAEs in 25% of percussionists vs 10% of nonpercussionists). When all frequencies are considered as a group, 33% of the percussionists had an absent DPOAE in either ear at some frequency, compared to only 23% of the nonpercussionists. Otoacoustic emissions are more sensitive to outer hair cell damage than pure-tone threshold measurements and can serve as an important measurement of sensory loss (i.e., outer hair cell damage) in musicians before the person perceives the hearing loss. DPOAE monitoring for musicians, along with appropriate education and intervention, might help prevent or minimize music-induced hearing loss.

Contralateral Suppression of Otoacoustic Emissions: An Index of the Function of the Medial Olivocochlear System

1994 ◽  
Vol 110 (1) ◽  
pp. 3-21 ◽  
Author(s):  
Charles I. Berlin ◽  
Linda J. Hood ◽  
Annette Hurley ◽  
Han Wen
Keyword(s):  
Hair Cell ◽  
Middle Ear ◽  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Microstructural Analysis ◽  
Nerve Fibers ◽  
Speech Comprehension ◽  
Unique Type ◽  
Olivocochlear System ◽  
Contralateral Suppression

We can now distinguish, in part, between nerve deafness and hair cell deafness through the use of otoacoustic emissions. We can also assess the efferent system by carefully quantifying the effects of contralateral stimulation on these same otoacoustic emissions. The suppression of transient evoked emissions by continuous contralateral white noise is an ostensibly small effect of 2 or 3 dB when studied over a 20-msec window. However, when subjected to microstructural analysis, the effect can exceed 6 to 8 dB in the zones from 10 to 20 msec after the stimulus has subsided. Temporal and spectral analyses reveal robust effects of contralateral lateral stimulation, although in any given normal subject it may be difficult to separate middle ear effects from efferent effects. Evidence is strong that the efferent effect is mediated in part by cholinergic — primarily nicotinic — receptors in the outer hair cell. However, a unique type of patient, who shows nearly normal pure-tone audiograms and absent ABRs, shows virtually no contralateral suppression of transient evoked emissions. Some other patients, with symptoms of Charcot-Marie-Tooth disease, may paradoxically show extremely poor audiograms, but perfectly normal evoked emissions along with absent contralateral suppression. The ABR, along with middle ear muscle reflexes and masking level differences, are all absent in these patients; we therefore think they have a disorder that desynchronizes most of their primary auditory nerve fibers and thereby disconnects them from any efferent activity or masking cancellation. The existence of such an auditory disorder, characterized by severe dysfunction in speech comprehension — especially when listening in noise—suggests that what appears to be a “central auditory imperception” might stem instead from a systemic peripheral primary neuropathy.

scholarly journals Evaluation of outer hair cells function of non-operated ear after mastoid drilling using distortion-product otoacoustic emissions

2019 ◽  
Vol 5 (3) ◽  
pp. 130-133
Author(s):  
Virender Singh ◽  
◽  
BS Rakesh ◽  
MB Bharathi ◽  
Kota Harish Nag ◽  
...  
Keyword(s):  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Cell Function ◽  
Outer Hair Cells ◽  
Distortion Product Otoacoustic Emissions ◽  
Mechanical Trauma ◽  
Suppurative Otitis Media ◽  
Distortion Product ◽  
Study Materials ◽  
And Gender

Aim: To analyze the effect of acoustic and mechanical trauma of drilling on the outer hair cell function of the non operated ear using distortion-product otoacoustic emissions (DPOAE’s) after mastoidectomy and its relation with the duration of drilling, age, and gender of the patient along with duration and permanency of the effects. Study Design: Observational study. Materials and Methods: Screening DPOAE’s were recorded preoperatively, immediate postoperative period, one hour postoperatively, 1st and 7th postoperative days in the normal ear in 94 patients who underwent tympanomastoidectomy for unilateral chronic suppurative otitis media (CSOM). DPOAE’s were measured using Neuro-audio-screener (Neurosoft Inc.) at 1.5 KHz, 2.1 KHz, 3.3 KHz, and 4.2 KHz. If DPOAE’s were absent preoperatively, the patients were not evaluated further and patients who had absent DPOAE’s post-operatively were successively followed till DPOAE’s were regained. Results: Of the 94 patients included, in 62 patients DPOAE’s were present preoperatively. Out of these 62, in 30 patients DPOAE’s were absent immediate postoperatively. On repeat testing, DPOAE’s were absent in 20 patients after 1 hour and in 8 patients after 1 day. On re-evaluation of these 8 patients after 1 week all of them had regained the DPOAE’s. In terms of duration of drilling, 66.6% patients in immediate post operative period, 90% patients in 1-hour post operative and 100 % patients on post operative day 1, having absent DPOAE’s had drilling time more than 60 minutes. Patients more than 30 years of age are affected more, but there is no preponderance for any gender. Conclusion: Nonoperated ear does have the effect of acoustic and mechanical trauma by vibration transmitted from another side during drilling of the operative ear mastoid bone. This effect is temporary and depends on the duration of drilling also.

scholarly journals Deletion of Oncomodulin Gives Rise to Early Progressive Cochlear Dysfunction in C57 and CBA Mice

2021 ◽  
Vol 13 ◽  
Author(s):  
Leslie K. Climer ◽  
Aubrey J. Hornak ◽  
Kaitlin Murtha ◽  
Yang Yang ◽  
Andrew M. Cox ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Cell Function ◽  
Otoacoustic Emission ◽  
Cell Types ◽  
Auditory Brainstem ◽  
Outer Hair Cells ◽  
Distortion Product Otoacoustic Emission ◽  
Distortion Product ◽  
Age Related ◽  
Brainstem Response

Ca2+ signaling is a major contributor to sensory hair cell function in the cochlea. Oncomodulin (OCM) is a Ca2+ binding protein (CaBP) preferentially expressed in outer hair cells (OHCs) of the cochlea and few other specialized cell types. Here, we expand on our previous reports and show that OCM delays hearing loss in mice of two different genetic backgrounds: CBA/CaJ and C57Bl/6J. In both backgrounds, genetic disruption of Ocm leads to early progressive hearing loss as measured by auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE). In both strains, loss of Ocm reduced hearing across lifetime (hearing span) by more than 50% relative to wild type (WT). Even though the two WT strains have very different hearing spans, OCM plays a considerable and similar role within their genetic environment to regulate hearing function. The accelerated age-related hearing loss (ARHL) of the Ocm KO illustrates the importance of Ca2+ signaling in maintaining hearing health. Manipulation of OCM and Ca2+ signaling may reveal important clues to the systems of function/dysfunction that lead to ARHL.

scholarly journals The Impacts of Noise Exposure on the Middle Ear Muscle Reflex in a Veteran Population

2021 ◽  
Author(s):  
Naomi Bramhall ◽  
Kelly M. Reavis ◽  
M. Patrick Feeney ◽  
Sean Kampel
Keyword(s):  
Animal Models ◽  
Middle Ear ◽  
Noise Exposure ◽  
Outer Hair Cell ◽  
Auditory Brainstem ◽  
Nerve Fibers ◽  
Intensity Level ◽  
Physiological Indicators ◽  
Brainstem Response ◽  
Muscle Reflex

Noise-induced cochlear synaptopathy, the loss of the synaptic connections between inner hair cells and afferent auditory nerve fibers, has been demonstrated in multiple animal models, including non-human primates. However, given that synaptopathy can only be confirmed with post-mortem temporal bone analysis, it has been difficult to determine whether noise-induced synaptopathy occurs in humans. Human studies of noise-induced synaptopathy using physiological indicators identified in animal models (auditory brainstem response [ABR] wave I amplitude, the envelope following response [EFR], and the middle ear muscle reflex [MEMR]) have yielded mixed findings. Differences in the population studied may have contributed to the differing results. For example, due to differences in the intensity level of the noise exposure, noise-induced synaptopathy may be easier to detect in a military Veteran population than in populations with recreational noise exposure. We previously demonstrated a reduction in ABR wave I amplitude and EFR magnitude for young Veterans with normal audiograms reporting high levels of noise exposure compared to non-Veteran controls. In this report, we expand on the previous analysis in the same population to determine if MEMR magnitude is similarly reduced. The results of the statistical analysis, although not conventionally statistically significant, suggest a reduction in mean MEMR magnitude for Veterans reporting high noise exposure compared with non-Veteran controls. In addition, the MEMR appears relatively insensitive to subclinical outer hair cell dysfunction and is not well correlated with ABR and EFR measurements. When combined with our previous ABR and EFR findings in the same population, these results suggest that noise-induced synaptopathy occurs in humans. In addition, the findings indicate that the MEMR may be a good candidate for non-invasive diagnosis of cochlear synaptopathy/deafferentation and that the MEMR may reflect the integrity of different neural populations than the ABR and EFR.

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