Cochlear Dead Regions in Sporadic Unilateral Vestibular Schwannomas Using the Threshold-Equalizing Noise Test

2019 ◽  
Vol 24 (6) ◽  
pp. 271-278
Author(s):  
Hayoung Byun ◽  
Yang-Sun Cho ◽  
Sung Hwa Hong ◽  
Il Joon Moon
Keyword(s):  
Hearing Loss ◽  
Pure Tone ◽  
Spiral Ganglion ◽  
Tumor Location ◽  
Common Symptom ◽  
Low Frequencies ◽  
Hearing Thresholds ◽  
Ganglion Neurons ◽  
Cochlear Dead Regions

Background: Vestibular schwannoma (VS) is a benign intracranial neoplasm originating in the Schwann cells of the vestibular nerve. Despite its origin, the most common symptom is sensorineural hearing loss which is presented in more than 90% of patients. The underlying pathophysiology of this hearing loss has not been fully understood. Objective: To assess the in vivo function of cochlear inner hair cells and spiral ganglion neurons in VS, cochlear dead regions (DRs) were evaluated via the threshold-equalizing noise (TEN) test in untreated VS patients. Method: Untreated patients diagnosed with sporadic unilateral VS and normal contralesional hearing were enrolled from July 2011 to June 2016. Audiometric evaluation including TEN tests were performed. Based on the magnetic resonance findings, characteristics of individual tumors were assessed. Results: The average pure-tone threshold (word recognition score [WRS]) of 23 enrolled patients was 42.7 dB (76.1%). Nineteen DRs (11.8% of 161 tested frequencies) were found in 8 patients (34.8% of enrolled cases). Among the intracanalicular (IAC) tumors, 6 out of 10 ears (60%) carried DRs, while 2 of 13 (15.4%) showed DRs among the cerebellopontine angle (CPA) lesions (p = 0.039). Pure-tone thresholds and WRS were not different between the two groups. Logistic regression analysis showed that the tumor location, IAC versus CPA, was significantly associated with DRs (p = 0.041, Nagelkerke R2 = 0.471), whereas age, sex, tumor size, distance from the tumor to the cochlea, T2-weighted hypointensity on the MRI and pure-tone thresholds showed no significance. Conclusions: Cochlear DRs are detected in hearing losses associated with unilateral sporadic VS using the TEN test. Individual DRs were detected variously in high, mid, or low frequencies. In our preliminary data, IAC tumors showed a higher number of DRs than CPA tumors despite similar average hearing thresholds. Further studies including longitudinal follow-up of hearing as well as change in DRs may provide useful information about VS patients.

scholarly journals Exacerbated age-related hearing loss in mice lacking the p43 mitochondrial T3 receptor

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Corentin Affortit ◽  
François Casas ◽  
Sabine Ladrech ◽  
Jean-Charles Ceccato ◽  
Jérôme Bourien ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Spiral Ganglion ◽  
Electrophysiological Recording ◽  
Mitochondrial Activity ◽  
P53 Expression ◽  
Age Related ◽  
Hearing Function ◽  
Ganglion Neurons ◽  
Age Related Hearing Loss

Abstract Background Age-related hearing loss (ARHL), also known as presbycusis, is the most common sensory impairment seen in elderly people. However, the cochlear aging process does not affect people uniformly, suggesting that both genetic and environmental (e.g., noise, ototoxic drugs) factors and their interaction may influence the onset and severity of ARHL. Considering the potential links between thyroid hormone, mitochondrial activity, and hearing, here, we probed the role of p43, a N-terminally truncated and ligand-binding form of the nuclear receptor TRα1, in hearing function and in the maintenance of hearing during aging in p43−/− mice through complementary approaches, including in vivo electrophysiological recording, ultrastructural assessments, biochemistry, and molecular biology. Results We found that the p43−/− mice exhibit no obvious hearing loss in juvenile stages, but that these mice developed a premature, and more severe, ARHL resulting from the loss of cochlear sensory outer and inner hair cells and degeneration of spiral ganglion neurons. Exacerbated ARHL in p43−/− mice was associated with the early occurrence of a drastic fall of SIRT1 expression, together with an imbalance between pro-apoptotic Bax, p53 expression, and anti-apoptotic Bcl2 expression, as well as an increase in mitochondrial dysfunction, oxidative stress, and inflammatory process. Finally, p43−/− mice were also more vulnerable to noise-induced hearing loss. Conclusions These results demonstrate for the first time a requirement for p43 in the maintenance of hearing during aging and highlight the need to probe the potential link between human THRA gene polymorphisms and/or mutations and accelerated age-related deafness or some adult-onset syndromic deafness.

scholarly journals Physiopathological Relevance of D-Serine in the Mammalian Cochlea

2021 ◽  
Vol 15 ◽  
Author(s):  
Jing Wang ◽  
Nicolas Serratrice ◽  
Cindy J. Lee ◽  
Florence François ◽  
Jonathan V. Sweedler ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Nmda Receptors ◽  
Guinea Pigs ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Nerve Fibers ◽  
Inner Hair Cell ◽  
Ganglion Neurons

NMDA receptors (NMDARs) populate the complex between inner hair cell (IHC) and spiral ganglion neurons (SGNs) in the developing and mature cochlea. However, in the mature cochlea, activation of NMDARs is thought to mainly occur under pathological conditions such as excitotoxicity. Ototoxic drugs such as aspirin enable cochlear arachidonic-acid-sensitive NMDAR responses, and induced chronic tinnitus was blocked by local application of NMDAR antagonists into the cochlear fluids. We largely ignore if other modulators are also engaged. In the brain, D-serine is the primary physiological co-agonist of synaptic NMDARs. Whether D-serine plays a role in the cochlea had remained unexplored. We now reveal the presence of D-serine and its metabolic enzymes prior to, and at hearing onset, in the sensory and non-neuronal cells of the cochlea of several vertebrate species. In vivo intracochlear perfusion of D-serine in guinea pigs reduces sound-evoked activity of auditory nerve fibers without affecting the receptor potentials, suggesting that D-serine acts specifically on the postsynaptic auditory neurons without altering the functional state of IHC or of the stria vascularis. Indeed, we demonstrate in vitro that agonist-induced activation of NMDARs produces robust calcium responses in rat SGN somata only in the presence of D-serine, but not of glycine. Surprisingly, genetic deletion in mice of serine racemase (SR), the enzyme that catalyzes D-serine, does not affect hearing function, but offers protection against noise-induced permanent hearing loss as measured 3 months after exposure. However, the mechanisms of activation of NMDA receptors in newborn rats may be different from those in adult guinea pigs. Taken together, these results demonstrate for the first time that the neuro-messenger D-serine has a pivotal role in the cochlea by promoting the activation of silent cochlear NMDAR in pathological situations. Thus, D-serine and its signaling pathway may represent a new druggable target for treating sensorineural hearing disorders (i.e., hearing loss, tinnitus).

Hearing recovery from deafness caused by bromate intoxication

2018 ◽  
Vol 132 (11) ◽  
pp. 1039-1041 ◽  
Author(s):  
J Suzuki ◽  
Y Takanashi ◽  
A Koyama ◽  
Y Katori
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Pure Tone ◽  
Pure Tone Audiometry ◽  
Auditory Brainstem ◽  
Sensorineural Hearing ◽  
Auditory Brainstem Responses ◽  
Common Symptom ◽  
Hearing Recovery ◽  
Continuous Haemodiafiltration

AbstractObjectivesSodium bromate is a strong oxidant, and bromate intoxication can cause irreversible severe-to-profound sensorineural hearing loss. This paper reports the first case in the English literature of bromate-induced hearing loss with hearing recovery measured by formal audiological assessment.Case reportA 72-year-old woman was admitted to hospital with complaints of profound hearing loss, nausea, diarrhoea and anuria after bromate ingestion in a suicide attempt. On admission, pure tone audiometry and auditory brainstem responses showed profound bilateral deafness. Under the diagnosis of bromate-induced acute renal failure and sensorineural hearing loss, continuous haemodiafiltration was performed. When dialysis was discontinued, pure tone audiometry and auditory brainstem responses showed partial threshold recovery from profound deafness.ConclusionSevere-to-profound sensorineural hearing loss is a common symptom of bromate intoxication. Bromate-induced hearing loss may be partially treated, and early application of continuous haemodiafiltration might be useful as a treatment for this intractable condition.

Evaluation of Hearing and Balance Functions of Patients with Sickle Cell Anemia

2018 ◽  
Vol 23 (2) ◽  
pp. 122-125 ◽  
Author(s):  
Elif Tugba Sarac ◽  
Bilgehan Boke ◽  
Semsettin Okuyucu
Keyword(s):  
Hearing Loss ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Pure Tone ◽  
Mixed Type ◽  
Normal Hearing ◽  
Spontaneous Nystagmus ◽  
Control Group ◽  
Hearing Thresholds ◽  
Significant Difference

Introduction: Sickle cell anemia is a disease characterized by a wide vaso-occlusive incident from micro-vascular incident to muscularactivity. The cochlear function can also get affected by this vaso-occlusion. Objective: It is aimed at determining what kind of effects sickle cell anemia has on hearing and balance system. Methods: This study has been conducted on 46 patients with sickle cell anemia and 45 healthy individuals. For all participants, their pure tone hearing thresholds and videonystagmography (VNG) findings have been determined in 17 frequencies between 125–16.000 Hz. Results: All hearing thresholds between 125 and 16,000 Hz, pure tone averages of patients with sickle cell anemia have been found statistically significant to be higher than the corresponding values in the control group(p < 0.05). The normal hearing rate of patients with sickle cell anemia has been determined to be 71.1% conductive hearing loss (CHL) to be 4.4%, sensorineural hearing loss (SNHL) to be 22.2%, and mixed type hearing loss to be 2.2% in right ear; the normal hearing rate has been determined to be 71.1%, CHL to be 2.2%, SNHL to be 22.2%, and mixed type hearing loss to be 4.4% in left ear. Statistically significant difference has not been found between head shake, spontaneous nystagmus, optokinetic, tracking test batteries, static and dynamic positional tests used in VNG, saccade accuracy and saccade peak velocity, which are saccadic test findings of 2 groups. However, saccadic latency, which is a saccadic test finding, has been determined to be longer in patients with sickle cell anemia in comparison to the control group. Conclusion: While sickle cell anemia causes hearing deficits, it does not have any effect on the central or peripheral vestibular system.

scholarly journals Intrinsically Self-renewing Neuroprogenitors From the A/J Mouse Spiral Ganglion as Virtually Unlimited Source of Mature Auditory Neurons

2020 ◽  
Vol 14 ◽  
Author(s):  
Francis Rousset ◽  
Vivianne B. C. Kokje ◽  
Rebecca Sipione ◽  
Dominik Schmidbauer ◽  
German Nacher-Soler ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Progenitor Cells ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Specific Cell ◽  
Auditory Neurons ◽  
Self Renewal ◽  
Starting Point ◽  
Ganglion Neurons

Nearly 460 million individuals are affected by sensorineural hearing loss (SNHL), one of the most common human sensory disorders. In mammals, hearing loss is permanent due to the lack of efficient regenerative capacity of the sensory epithelia and spiral ganglion neurons (SGN). Sphere-forming progenitor cells can be isolated from the mammalian inner ear and give rise to inner ear specific cell types in vitro. However, the self-renewing capacities of auditory progenitor cells from the sensory and neuronal compartment are limited to few passages, even after adding powerful growth factor cocktails. Here, we provide phenotypical and functional characterization of a new pool of auditory progenitors as sustainable source for sphere-derived auditory neurons. The so-called phoenix auditory neuroprogenitors, isolated from the A/J mouse spiral ganglion, exhibit robust intrinsic self-renewal properties beyond 40 passages. At any passage or freezing–thawing cycle, phoenix spheres can be efficiently differentiated into mature spiral ganglion cells by withdrawing growth factors. The differentiated cells express both neuronal and glial cell phenotypic markers and exhibit similar functional properties as mouse spiral ganglion primary explants and human sphere-derived spiral ganglion cells. In contrast to other rodent models aiming at sustained production of auditory neurons, no genetic transformation of the progenitors is needed. Phoenix spheres therefore represent an interesting starting point to further investigate self-renewal in the mammalian inner ear, which is still far from any clinical application. In the meantime, phoenix spheres already offer an unlimited source of mammalian auditory neurons for high-throughput screens while substantially reducing the numbers of animals needed.

scholarly journals Functional Roles of High-Affinity Glutamate Transporters in Cochlear Afferent Synaptic Transmission in the Mouse

2010 ◽  
Vol 103 (5) ◽  
pp. 2581-2586 ◽  
Author(s):  
Zhiqiang Chen ◽  
Sharon G. Kujawa ◽  
William F. Sewell
Keyword(s):  
Hearing Loss ◽  
Otoacoustic Emissions ◽  
Excitatory Amino Acid ◽  
Spiral Ganglion ◽  
Glutamate Transporter ◽  
Glutamate Transporters ◽  
Acoustic Stimulation ◽  
Noise Induced Hearing Loss ◽  
Glutamate Transporter 1 ◽  
Ganglion Neurons

In the cochlea, afferent transmission between inner hair cells and auditory neurons is mediated by glutamate receptors. Glutamate transporters located near the synapse and in spiral ganglion neurons are thought to maintain low synaptic levels of glutamate. We analyzed three glutamate transporter blockers for their ability to alter the effects of glutamate, exogenously applied to the synapse via perfusion of the scala tympani of the mouse, and compared that action to their ability to alter the effects of intense acoustic stimulation. Threo-beta-benzyloxyaspartate (TBOA) is a broad-spectrum glutamate transporter antagonist, affecting all three transporters [glutamate/aspartate transporter (GLAST), glutamate transporter-1 (GLT1), and excitatory amino acid carrier 1 (EAAC1)]. l-serine- O-sulfate (SOS) blocks both GLAST and EAAC1 without effect on GLT1. Dihydrokainate (DHK) is selective for GLT1. Infusion of glutamate (10 μM for 220 min), TBOA (200 μM for 220 min), or SOS (100 μM for 180 min) alone did not alter auditory neural thresholds. When infused together with glutamate, TBOA and SOS produced significant neural threshold shifts, leaving otoacoustic emissions intact. In addition, both TBOA and SOS exacerbated noise-induced hearing loss by producing larger neural threshold shifts and delaying recovery. DHK did not alter glutamate- or noise-induced hearing loss. The evidence points to a major role for GLAST, both in protecting the synapse from exposure to excess extracellular glutamate and in attenuating hearing loss due to acoustic overstimulation.

scholarly journals Spatiotemporal Developmental Upregulation of Prestin Correlates With the Severity and Location of Cyclodextrin-Induced Outer Hair Cell Loss and Hearing Loss

2021 ◽  
Vol 9 ◽  
Author(s):  
Dalian Ding ◽  
Haiyan Jiang ◽  
Senthilvelan Manohar ◽  
Xiaopeng Liu ◽  
Li Li ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hair Cells ◽  
Auditory Nerve ◽  
High Frequency ◽  
Spiral Ganglion ◽  
Low Frequency ◽  
Nerve Fibers ◽  
Spiral Ganglion Neurons ◽  
Auditory Nerve Fibers ◽  
Ganglion Neurons

2-Hyroxypropyl-beta-cyclodextrin (HPβCD) is being used to treat Niemann-Pick C1, a fatal neurodegenerative disease caused by abnormal cholesterol metabolism. HPβCD slows disease progression, but unfortunately causes severe, rapid onset hearing loss by destroying the outer hair cells (OHC). HPβCD-induced damage is believed to be related to the expression of prestin in OHCs. Because prestin is postnatally upregulated from the cochlear base toward the apex, we hypothesized that HPβCD ototoxicity would spread from the high-frequency base toward the low-frequency apex of the cochlea. Consistent with this hypothesis, cochlear hearing impairments and OHC loss rapidly spread from the high-frequency base toward the low-frequency apex of the cochlea when HPβCD administration shifted from postnatal day 3 (P3) to P28. HPβCD-induced histopathologies were initially confined to the OHCs, but between 4- and 6-weeks post-treatment, there was an unexpected, rapid and massive expansion of the lesion to include most inner hair cells (IHC), pillar cells (PC), peripheral auditory nerve fibers, and spiral ganglion neurons at location where OHCs were missing. The magnitude and spatial extent of HPβCD-induced OHC death was tightly correlated with the postnatal day when HPβCD was administered which coincided with the spatiotemporal upregulation of prestin in OHCs. A second, massive wave of degeneration involving IHCs, PC, auditory nerve fibers and spiral ganglion neurons abruptly emerged 4–6 weeks post-HPβCD treatment. This secondary wave of degeneration combined with the initial OHC loss results in a profound, irreversible hearing loss.

scholarly journals Η συμβολή των ωτοακουστικών εκπομπών στη μελέτη της κοχλιακής λειτουργίας σε ασθενείς με υποθυρεοειδισμό

2013 ◽  
Author(s):  
Βασίλειος Ψαλτάκος
Keyword(s):  
Hearing Loss ◽  
Hearing Impairment ◽  
Otoacoustic Emissions ◽  
Pure Tone ◽  
Pure Tone Audiometry ◽  
Otoacoustic Emission ◽  
Upper Respiratory Tract ◽  
Anatomic Site ◽  
Cochlear Function ◽  
Hearing Thresholds

Although several reports exist concerning the occurrence of hearing loss in patients withdisorders of thyroid function, there are still several unsettled issues, such as theincidence and the severity of hearing impairment, the anatomic site of the auditorypathway involved, and the possible pathogenetic mechanisms. Both congenitalhypothyroidism and environmentally based iodine deficiency are established causes ofhearing loss in humans and rodents. Congenital thyroid deficiency in humans can resultin a profound, hearing deficit, which may be prevented by early hormonal replacementtreatment in infants with hypothyroidism. However, the effect of acute or chronichypothyroidism in adults has not been adequately studied, and most information hasbeen obtained from animal experiments, whereas research in humans has been basicallybased on behavioral audiometry. The use of otoacoustic emissions may provide moreinsight into the hearing function of these patients than pure-tone audiometry, since it isconsidered as a sensitive test of the cochlear status. The aim of this study was toevaluate the hearing in a group of patients with acute hypothyroidism, using bothconventional audiometry and transiently evoked otoacoustic emissions (TEOAEs). Material and methods:A group of 52 patients with thyroid carcinoma who underwent total thyroidectomy wasstudied prospectively, All patients were examined before surgery and 6-8 weekspostoperatively. During this period there was no replacement with levothyroxine and themagnitude of thyroxin depletion was monitored by serum thyroid-stimulating hormone levels. On preoperative encounter with each patient, a detailed questionnaire of historyof hearing loss, tinnitus, vertigo, previous ear infections, noise exposure, medications,and recent upper respiratory tract infection was completed. Patients were excluded ifthey were older than 50 years, in order to avoid the phenomenon of presbycusis, or ifthey had a history of cochleovestibular, vascular or neurologic disease, or any other riskfactor for hearing impairment. Pure-tone audiometry, tympanometry and transientlyevoked otoacoustic emissions were performed. A group of healthy volunteers of similarage and sex were used for comparison.Results:(1) Tympanograms were normal, either on initial testing (75%) or on repeat testing(25%).(2) Audiometry showed elevation of all postoperative hearing thresholds, whereas thethresholds varied significantly across frequency.(3) TEOAE testing showed response signal to noise ratios lower in the postoperativesession (hypothyroid state) than in the preoperative session on all measured frequencies.(4) Emission levels varied significantly across frequency, with maximum responseobserved at 2 kHz.(5) Comparison of significant pure-tone and otoacoustic emission shifts for individualears showed more ears affected in otoacoustic emission testing, indicating subclinicalcochlear involvement.(6) Comparison of hearing thresholds and otoacoustic emission levels between patientsand controls showed significant differences on postoperative testing. Conclusions:Acute hypothyroidism in adults causes elevation of hearing thresholds and reducedotoacoustic emissions. The effect on otoacoustic emissions is greater, indicatingsubclinical damage of the cochlear function.

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