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1.
Ear Nose Throat J ; 100(3): NP141-NP146, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31547716

RESUMO

Otitis media with effusion is a common cause of diminished hearing in children younger than 12 years. Hypertrophy of adenoids is one of the commonest etiologies of this condition. It has been mentioned that with increased size of the adenoid tissue, the more likely the incidence of fluid in the middle ear. The aim of this study was to find whether there is a correlation between adenoid size, tympanometric findings, and type of fluid in the middle ear irrespective of disease duration. This is a prospective study done on 100 pediatric patients (12 years and less) presented with chronic otitis media with effusion (COME) and adenoid hypertrophy from July 2015 till July 2017. Cases with tympanometry evidence of COME (B, Cs) and adenoid hypertrophy seen by nasal endoscopy were included. Adenoid size was graded and correlated with the type of tympanometry and type of fluid in the middle ear. Sixty male children and 40 female children were involved. Age ranged from 3 to 12 years with a mean of 7.19 ± 2.489 years. Highly significant relation existed between grade 4 adenoid hypertrophy and mucoid nature of middle ear fluid (P value = .000). There is a highly significant relation between adenoid hypertrophy grade Ⅳ and type B tympanometry. There is a highly significant relation between adenoid size and nature of middle ear fluid irrespective of the duration of complaints, where grade Ⅳ adenoid hypertrophy showed more increase in middle ear effusion viscosity making adenoid size a very important predictor for the tympanometry type and the nature of the fluid in the middle ear.


Assuntos
Testes de Impedância Acústica , Tonsila Faríngea/patologia , Líquidos Labirínticos/química , Otite Média com Derrame/patologia , Criança , Pré-Escolar , Correlação de Dados , Orelha Média/química , Feminino , Humanos , Hipertrofia , Masculino , Omã , Estudos Prospectivos , Viscosidade
2.
Sci Rep ; 10(1): 16564, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-33024221

RESUMO

Our ability to hear through bone conduction (BC) has long been recognized, but the underlying mechanism is poorly understood. Why certain perturbations affect BC hearing is also unclear. An example is BC hyperacusis (hypersensitive BC hearing)-an unnerving symptom experienced by patients with superior canal dehiscence (SCD). We measured BC-evoked sound pressures in scala vestibuli (PSV) and scala tympani (PST) at the basal cochlea in cadaveric human ears, and estimated hearing by the cochlear input drive (PDIFF = PSV - PST) before and after creating an SCD. Consistent with clinical audiograms, SCD increased BC-driven PDIFF below 1 kHz. However, SCD affected the individual scalae pressures in unexpected ways: SCD increased PSV below 1 kHz, but had little effect on PST. These new findings are inconsistent with the inner-ear compression mechanism that some have used to explain BC hyperacusis. We developed a computational BC model based on the inner-ear fluid-inertia mechanism, and the simulated effects of SCD were similar to the experimental findings. This experimental-modeling study suggests that (1) inner-ear fluid inertia is an important mechanism for BC hearing, and (2) SCD facilitates the flow of sound volume velocity through the cochlear partition at low frequencies, resulting in BC hyperacusis.


Assuntos
Audição/fisiologia , Hiperacusia/fisiopatologia , Deiscência do Canal Semicircular/fisiopatologia , Condução Óssea/fisiologia , Cadáver , Cóclea/fisiologia , Humanos , Líquidos Labirínticos/fisiologia , Rampa do Tímpano/fisiologia , Canais Semicirculares/fisiopatologia , Som
3.
Otol Neurotol ; 39(6): 755-764, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29889786

RESUMO

HYPOTHESIS: Insertion of cochlear implant electrodes generates transient pressure spikes within the vestibular labyrinth equivalent to high-intensity acoustic stimuli. BACKGROUND: Though cochlear implant (CI) surgery is regarded as having low risk of impacting the vestibular system, several studies have documented changes in vestibular function after implantation. The mechanism of these changes is not understood. We have previously established that large, potentially damaging pressure transients can be generated in the cochlea during electrode insertion, but whether pressure transients occur within the vestibular labyrinth has yet to be determined. Here, we quantify the exposure of the vestibular system to potentially damaging pressure transients during CI surgery. METHODS: Five human cadaveric heads were prepared with an extended facial recess and implanted sequentially with eight different CI electrode styles via a round window approach. Fiber-optic sensors measured intralabyrinthine pressures in scala vestibuli, scala tympani, and the lateral semicircular canal during insertions. RESULTS: Electrode insertion produced a range of high-intensity pressure spikes simultaneously in the cochlea and lateral semicircular canal with all electrodes tested. Pressure transients recorded were found to be significantly higher in the vestibular labyrinth than the cochlea and occurred at peak levels known to cause acoustic trauma. CONCLUSION: Insertion of CI electrodes can produce transients in intralabyrinthine fluid pressure levels equivalent to high-intensity, impulsive acoustic stimuli. Results from this investigation affirm the importance of atraumatic surgical techniques and suggest that in addition to the cochlea, the vestibular system is potentially exposed to damaging fluid pressure waves during cochlear implantation.


Assuntos
Implante Coclear/efeitos adversos , Líquidos Labirínticos , Canais Semicirculares/fisiopatologia , Vestíbulo do Labirinto/fisiopatologia , Cadáver , Cóclea/cirurgia , Implante Coclear/métodos , Implantes Cocleares , Humanos , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/fisiopatologia , Pressão/efeitos adversos
4.
Auris Nasus Larynx ; 45(5): 1116-1120, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29680680

RESUMO

The present case was a 38-year-old male who presented with progressive hearing loss, resulting in profound bilateral hearing loss. He had a past history of childhood medulloblastoma, which was treated with posterior fossa craniotomy and radiotherapy. A ventriculoperitoneal (VP) shunt was put in place to manage the hydrocephalus. Cochlear implantation (CI) was carried out on his right ear by a standard procedure. At CI activation, the electric impedance of the electrode was very high, and computed tomography revealed that there was no area of liquid density, suggesting depletion of the perilymph in the cochlea and vestibule. Eight months later, the impedance improved gradually, and the cochlea was filled with perilymph. Consequently, one of the causes of the pneumolabyrinth in the present case was that a scarred stenotic cochlear canaliculus secondary to surgery or radiation therapy might have prevented the CSF from filling the scala. In addition, it is also possible that the VP shunt might have altered the CSF pressure, leading to depletion of the perilymph.


Assuntos
Impedância Elétrica , Perda Auditiva Bilateral/reabilitação , Doenças do Labirinto/fisiopatologia , Perilinfa , Complicações Pós-Operatórias/fisiopatologia , Vestíbulo do Labirinto , Adulto , Neoplasias Cerebelares/complicações , Neoplasias Cerebelares/terapia , Implante Coclear , Constrição Patológica/complicações , Craniotomia , Perda Auditiva Bilateral/complicações , Humanos , Hidrocefalia/etiologia , Hidrocefalia/cirurgia , Doenças do Labirinto/etiologia , Líquidos Labirínticos , Masculino , Meduloblastoma/complicações , Meduloblastoma/terapia , Procedimentos Neurocirúrgicos , Complicações Pós-Operatórias/etiologia , Radioterapia , Tomografia Computadorizada por Raios X , Derivação Ventriculoperitoneal
5.
Auris Nasus Larynx ; 45(1): 165-169, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28017492

RESUMO

Superior canal dehiscence is a pathologic condition of the otic capsule acting as aberrant window of the inner ear. It results in reduction of inner ear impedance and in abnormal exposure of the labyrinthine neuroepithelium to the action of the surrounding structures. The sum of these phenomena leads to the onset of typical cochleo-vestibular symptoms and signs. Among them, pulsatile tinnitus has been attributed to a direct transmission of intracranial vascular activities to labyrinthine fluids. We present the first video-otoscopic documentation of spontaneous pulse-synchronous movements of the tympanic membrane in two patients with superior canal dehiscence. Pulsating eardrum may represent an additional sign of third-mobile window lesion.


Assuntos
Canais Semicirculares/anormalidades , Zumbido/fisiopatologia , Idoso , Feminino , Humanos , Líquidos Labirínticos/fisiologia , Pessoa de Meia-Idade , Otoscopia , Canais Semicirculares/patologia , Canais Semicirculares/fisiopatologia , Zumbido/diagnóstico por imagem , Zumbido/etiologia , Aqueduto Vestibular/anormalidades , Vestíbulo do Labirinto
6.
Sci Rep ; 6: 19475, 2016 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-26792556

RESUMO

Since the discovery of otoacoustic emissions and outer hair cell (OHC) motility, the fundamental question of whether the cochlea produces mechanical power remains controversial. In the present work, direct calculations are performed on power loss due to fluid viscosity and power generated by the OHCs. A three-dimensional box model of the mouse cochlea is used with a feed-forward/feed-backward approximation representing the organ of Corti cytoarchitecture. The model is fit to in vivo basilar membrane motion with one free parameter for the OHCs. The calculations predict that the total power output from the three rows of OHCs can be over three orders of magnitude greater than the acoustic input power at 10 dB sound pressure level (SPL). While previous work shows that the power gain, or the negative damping, diminishes with intensity, we show explicitly based on our model that OHC power output increases and saturates with SPL. The total OHC power output is about 2 pW at 80 dB SPL, with a maximum of about 10 fW per OHC.


Assuntos
Potenciais Microfônicos da Cóclea , Células Ciliadas Auditivas Externas/fisiologia , Líquidos Labirínticos , Modelos Biológicos , Algoritmos , Líquidos Labirínticos/química , Órgão Espiral/citologia , Órgão Espiral/fisiologia
7.
Hear Res ; 340: 135-143, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-26657096

RESUMO

Five different pathways are often suggested as important for bone conducted (BC) sound: (1) sound pressure in the ear canal, (2) inertia of the middle ear ossicles, (3) inertia of the inner ear fluid, (4) compression of the inner ear space, and (5) pressure transmission from the skull interior. The relative importance of these pathways was investigated with an acoustic-impedance model of the inner ear. The model incorporated data of BC generated ear canal sound pressure, middle ear ossicle motion, cochlear promontory vibration, and intracranial sound pressure. With BC stimulation at the mastoid, the inner ear inertia dominated the excitation of the cochlea but inner ear compression and middle ear inertia were within 10 dB for almost the entire frequency range of 0.1-10 kHz. Ear canal sound pressure gave little contribution at the low and high frequencies, but was around 15 dB below the total contribution at the mid frequencies. Intracranial sound pressure gave responses similar to the others at low frequencies, but decreased with frequency to a level of 55 dB below the total contribution at 10 kHz. When the BC inner ear model was evaluated against AC stimulation at threshold levels, the results were close up to approximately 4 kHz but deviated significantly at higher frequencies.


Assuntos
Limiar Auditivo/fisiologia , Condução Óssea/fisiologia , Cóclea/fisiologia , Ossículos da Orelha/fisiologia , Estimulação Acústica , Percepção Auditiva , Simulação por Computador , Meato Acústico Externo/fisiologia , Orelha Média/fisiologia , Humanos , Líquidos Labirínticos , Pressão , Crânio/fisiologia , Som , Vibração
8.
Acta Otolaryngol ; 135(12): 1219-24, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26327567

RESUMO

CONCLUSIONS: Hydrostatic positive pressure and vasoconstrictor acidified the cochlear fluids, whereas the vasodilator made the fluids alkaline. CBF might play a role in regulating cochlea fluid pH. OBJECTIVES: Cochlea fluid pH is highly dependent on the HCO3(-)/CO2 buffer system. Cochlear blood flow (CBF) supplies O2 and removes CO2. It is speculated that cochlear blood flow changes might affect the balance of the HCO3(-)/CO2 buffer system in the cochlea. It is known that the elevation of inner ear pressure decreases the CBF, and local application of vasodilating or vasoconstricting agents directly to the cochlea changes the CBF. The purpose of this study was to elucidate the effect of positive hydrostatic inner ear pressure and application of a vasodilator and vasoconstrictor of cochlear vessels on the pH of the endolymph and perilymph. METHODS: The authors performed animal physiological experiments on 30 guinea pigs. Hydrostatic positive pressure was infused through a glass capillary tube inserted into the scala tympani of the basal turn. The vasodilator, nitric oxide donor (sodium nitroprusside; SNP), and the vasoconstrictor, bupivacaine, were placed topically onto the round window of the guinea pig cochlea. Endolymph pH (pHe) and endocochlear potential (EP) were monitored by double-barreled ion-selective microelectrodes in the second turn of the guinea pig cochlea. During the topical application study, scala vestibuli perilymph pH (pHv) was also measured simultaneously in the second turn. RESULTS: The application of hydrostatic positive pressure caused a decrease in pHe and EP. Positive perilymphatic pressure caused the endolymph to become acidic pressure-dependently. Application of 3.0% SNP evoked an increase in both the pHe and pHv, following by a gradual recovery to baseline levels. On the other hand, 0.5% bupivacaine caused a decrease in both the pHe and pHv. The EP during topical application showed slight, non-significant changes.


Assuntos
Bupivacaína/administração & dosagem , Cóclea/fisiologia , Potenciais Microfônicos da Cóclea/efeitos dos fármacos , Líquidos Labirínticos/química , Nitroprussiato/administração & dosagem , Anestésicos Locais/administração & dosagem , Animais , Cóclea/efeitos dos fármacos , Potenciais Evocados Auditivos/efeitos dos fármacos , Cobaias , Concentração de Íons de Hidrogênio , Doadores de Óxido Nítrico/administração & dosagem , Pressão , Janela da Cóclea
9.
Otol Neurotol ; 36(8): 1328-30, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26134936

RESUMO

OBJECTIVES: The aim of this study was to determine the prevalence of cochlear obliteration after labyrinthectomy. STUDY DESIGN: Retrospective review of medical records. SETTING: Tertiary referral center. PATIENTS: Sixty-five patients who had previously undergone resection of an acoustic neuroma through a translabyrinthine approach. INTERVENTION: The magnetic resonance studies were analyzed as part of the routine surveillance after tumor resection. MAIN OUTCOME MEASURE: To determine whether the cochlear lumen remained fluid filled. RESULTS: Sixty-five cochleas were examined. Forty-four cochleas were patent and, of the remaining 21, 9 were obliterated and 12 were partially obliterated. The average length of follow-up for the patent, partially obliterated, and obliterated cochlea groups was 47, 29, and 77 months, respectively. CONCLUSION: Obliteration of the cochlea, either partially or completely, occurs in approximately one-third of patients. Time elapsed after labyrinthectomy did not seem to be a predictor of cochlear obliteration.


Assuntos
Cóclea/lesões , Implante Coclear/métodos , Orelha Interna/cirurgia , Procedimentos Cirúrgicos Otológicos/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Líquidos Labirínticos , Imageamento por Ressonância Magnética , Masculino , Doença de Meniere/cirurgia , Pessoa de Meia-Idade , Neurofibromatose 2/cirurgia , Neuroma Acústico/cirurgia , Prevalência , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
10.
J Laryngol Otol ; 129(1): 11-5, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25482388

RESUMO

OBJECTIVE: Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging has been used to detect alterations in the composition of inner-ear fluid. This study investigated the association between hearing level and the signal intensity of pre- and post-contrast three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging in patients with sudden-onset sensorineural hearing loss. METHOD: Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging was performed in 18 patients with sudden-onset sensorineural hearing loss: 12 patients with mild-to-moderate sensorineural hearing loss (baseline hearing levels of 60 dB or less) and 6 patients with severe-to-profound sensorineural hearing loss (baseline hearing levels of more than 60 dB). RESULTS: High-intensity signals in the inner ear were observed in two of the six patients (33 per cent) with severe-to-profound sensorineural hearing loss, but not in those with mild-to-moderate sensorineural hearing loss (mid-p test, p = 0.049). These signals were observed on magnetic resonance imaging scans 6 or 18 days after sensorineural hearing loss onset. CONCLUSION: The results indicate that three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging is not a useful tool for detecting inner-ear abnormalities in patients with mild sensorineural hearing loss.


Assuntos
Limiar Auditivo/fisiologia , Orelha Interna/fisiopatologia , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Súbita/diagnóstico , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Audiometria , Cóclea/fisiopatologia , Meios de Contraste , Feminino , Perda Auditiva Neurossensorial/fisiopatologia , Perda Auditiva Súbita/fisiopatologia , Humanos , Líquidos Labirínticos , Masculino , Pessoa de Meia-Idade
11.
Hear Res ; 329: 41-51, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25528492

RESUMO

Bone conduction (BC) hearing relies on sound vibration transmission in the skull bone. Several clinical findings indicate that in the human, the skull vibration of the inner ear dominates the response for BC sound. Two phenomena transform the vibrations of the skull surrounding the inner ear to an excitation of the basilar membrane, (1) inertia of the inner ear fluid and (2) compression and expansion of the inner ear space. The relative importance of these two contributors were investigated using an impedance lumped element model. By dividing the motion of the inner ear boundary in common and differential motion it was found that the common motion dominated at frequencies below 7 kHz but above this frequency differential motion was greatest. When these motions were used to excite the model it was found that for the normal ear, the fluid inertia response was up to 20 dB greater than the compression response. This changed in the pathological ear where, for example, otosclerosis of the stapes depressed the fluid inertia response and improved the compression response so that inner ear compression dominated BC hearing at frequencies above 400 Hz. The model was also able to predict experimental and clinical findings of BC sensitivity in the literature, for example the so called Carhart notch in otosclerosis, increased BC sensitivity in superior semicircular canal dehiscence, and altered BC sensitivity following a vestibular fenestration and RW atresia.


Assuntos
Condução Óssea/fisiologia , Orelha Interna/fisiologia , Modelos Biológicos , Fenômenos Biomecânicos , Cóclea/fisiologia , Impedância Elétrica , Humanos , Líquidos Labirínticos/fisiologia , Janela do Vestíbulo/fisiologia , Janela da Cóclea/fisiologia , Vibração
12.
Rep Prog Phys ; 77(7): 076601, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25006839

RESUMO

Most sounds of interest consist of complex, time-dependent admixtures of tones of diverse frequencies and variable amplitudes. To detect and process these signals, the ear employs a highly nonlinear, adaptive, real-time spectral analyzer: the cochlea. Sound excites vibration of the eardrum and the three miniscule bones of the middle ear, the last of which acts as a piston to initiate oscillatory pressure changes within the liquid-filled chambers of the cochlea. The basilar membrane, an elastic band spiraling along the cochlea between two of these chambers, responds to these pressures by conducting a largely independent traveling wave for each frequency component of the input. Because the basilar membrane is graded in mass and stiffness along its length, however, each traveling wave grows in magnitude and decreases in wavelength until it peaks at a specific, frequency-dependent position: low frequencies propagate to the cochlear apex, whereas high frequencies culminate at the base. The oscillations of the basilar membrane deflect hair bundles, the mechanically sensitive organelles of the ear's sensory receptors, the hair cells. As mechanically sensitive ion channels open and close, each hair cell responds with an electrical signal that is chemically transmitted to an afferent nerve fiber and thence into the brain. In addition to transducing mechanical inputs, hair cells amplify them by two means. Channel gating endows a hair bundle with negative stiffness, an instability that interacts with the motor protein myosin-1c to produce a mechanical amplifier and oscillator. Acting through the piezoelectric membrane protein prestin, electrical responses also cause outer hair cells to elongate and shorten, thus pumping energy into the basilar membrane's movements. The two forms of motility constitute an active process that amplifies mechanical inputs, sharpens frequency discrimination, and confers a compressive nonlinearity on responsiveness. These features arise because the active process operates near a Hopf bifurcation, the generic properties of which explain several key features of hearing. Moreover, when the gain of the active process rises sufficiently in ultraquiet circumstances, the system traverses the bifurcation and even a normal ear actually emits sound. The remarkable properties of hearing thus stem from the propagation of traveling waves on a nonlinear and excitable medium.


Assuntos
Membrana Basilar/fisiologia , Células Ciliadas Auditivas/fisiologia , Audição/fisiologia , Líquidos Labirínticos/fisiologia , Mecanotransdução Celular/fisiologia , Modelos Biológicos , Animais , Orelha Interna/fisiologia , Humanos , Reologia/métodos , Estresse Mecânico , Viscosidade
13.
Hear Res ; 298: 93-103, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23296212

RESUMO

In animals, hearing loss resulting from cochlear mechanosensory cell damage can be mitigated by antioxidants such as d-methionine (d-met) and acetyl-l-carnitine (ALCAR). The systemic routes of administration of these compounds, that must of necessity transit trough the cochlear fluids, may affect the antioxidant levels in the cochlea and the resulting oto-protective effect. In this study, we analyzed the pharmacokinetics of [(14)C]d-met in the cochlea and four other tissues after intratracheal (IT), intranasal (IN), and oral by gavage (OG) administration and compared it to intravenous administration (IV). We then analyzed the effect of these four routes on the antioxidant content of the cochlear fluids after d-met or ALCAR administration, by liquid chromatography/mass spectrometry. Our results showed that the concentration of methionine and ALCAR in cochlear fluids significantly increased after their respective systemic administration. Interestingly, d-met administration also contributed to an increase of ALCAR. Our results also showed that the delivery routes differently affected the bioavailability of administered [(14)C]d-met as well as the concentrations of methionine, ALCAR and the ratio of oxidized to reduced glutathione. Overall, pulmonary delivery via IT administration achieved high concentrations of methionine, ALCAR, and oxidative-related metabolites in cochlear fluids, in some cases surpassing IV administration, while IN route appeared to be the least efficacious. To our knowledge, this is the first report of the direct measurements of antioxidant levels in cochlear fluids after their systemic administration. This report also demonstrates the validity of the pulmonary administration of antioxidants and highlights the different contributions of d-met and ALCAR allowing to further investigate their impact on oxidative stress in the cochlear microenvironment.


Assuntos
Acetilcarnitina/administração & dosagem , Acetilcarnitina/farmacocinética , Antioxidantes/administração & dosagem , Antioxidantes/farmacocinética , Glutationa/metabolismo , Líquidos Labirínticos/metabolismo , Metionina/administração & dosagem , Metionina/farmacocinética , Administração por Inalação , Administração Intranasal , Administração Oral , Animais , Disponibilidade Biológica , Biotransformação , Cromatografia Líquida de Alta Pressão , Endolinfa/metabolismo , Injeções Intravenosas , Masculino , Espectrometria de Massas , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Perilinfa/metabolismo , Ratos , Ratos Sprague-Dawley
14.
Vestn Otorinolaringol ; (5): 27-30, 2012.
Artigo em Russo | MEDLINE | ID: mdl-23250521

RESUMO

The objective of the present study was to analyse anatomical features of the middle ear in the premature infants of different gestational age. Materials from 100 still-born and live-born babies (200 temporal bones) were available for the investigation. The study has revealed a number of distinctive clinical and morphological peculiarities in the structure of tympanic membranes in both the prematurely born infants depending on the gestational age and in the full-term babies. The fluid from the tympanic cavity was found to contain human beta-chorionic gonadotropin.


Assuntos
Desenvolvimento Infantil/fisiologia , Gonadotropina Coriônica Humana Subunidade beta/metabolismo , Orelha Média , Idade Gestacional , Osso Temporal , Anatomia Regional/métodos , Orelha Média/crescimento & desenvolvimento , Orelha Média/metabolismo , Orelha Média/patologia , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Líquidos Labirínticos/metabolismo , Masculino , Osso Temporal/crescimento & desenvolvimento , Osso Temporal/patologia , Membrana Timpânica/crescimento & desenvolvimento , Membrana Timpânica/patologia
15.
J Laryngol Otol ; 126(6): 586-93, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22643203

RESUMO

OBJECTIVES: (1) To study the prevalence and characteristics of large endolymphatic sac internal compartments on thin-section T2- and T2*-weighted magnetic resonance imaging, and to relate these to other large endolymphatic sac magnetic resonance imaging features, and (2) to correlate the compartment imaging features, endolymphatic sac size and labyrinthine anomalies with the patients' clinical and audiological data. METHOD: Magnetic resonance imaging studies for 38 patients with large endolymphatic sac anomalies were retrospectively reviewed in a tertiary referral centre. Endolymphatic sac compartment presence, morphology and imaging signal were assessed. Endolymphatic sac size and labyrinthine anomalies were also recorded. Endolymphatic sac compartments and other imaging features were correlated with clinical and audiological data. RESULTS: Compartments were present in 57 per cent of the imaged endolymphatic sacs, but their presence alone did not correlate with other imaging features or clinical data. The endolymphatic sac : internal auditory meatus signal ratio was associated with a history of sudden or fluctuating hearing loss. Hearing loss correlated with opercular and extraosseous endolymphatic sac size measurements. A larger midpoint intraosseous endolymphatic sac size was associated with clear fluid loss at cochlear implantation. CONCLUSION: The magnetic resonance imaging characteristics of large endolymphatic sac compartments have been defined. The endolymphatic sac size and distal compartment signal should be recorded, as these provide prognostic information and assist the planning of appropriate interventions.


Assuntos
Implante Coclear , Saco Endolinfático/patologia , Perda Auditiva Súbita/patologia , Imageamento por Ressonância Magnética/métodos , Adolescente , Adulto , Idoso , Audiometria de Tons Puros , Criança , Pré-Escolar , Progressão da Doença , Saco Endolinfático/anormalidades , Feminino , Perda Auditiva Súbita/diagnóstico , Perda Auditiva Súbita/fisiopatologia , Humanos , Processamento de Imagem Assistida por Computador , Lactente , Líquidos Labirínticos/química , Líquidos Labirínticos/metabolismo , Masculino , Pessoa de Meia-Idade , Prognóstico , Reprodutibilidade dos Testes , Estudos Retrospectivos , Estatísticas não Paramétricas , Adulto Jovem
16.
Eur Arch Otorhinolaryngol ; 269(7): 1755-8, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22045302

RESUMO

Since inner ear hair cells are mechano-electric transducers the control of hydrostatic pressure in the inner ear is crucial. Most studies analyzing dynamics and regulation of inner ear hydrostatic pressure performed pressure measurements in the cochlea. The present study is the first one reporting about absolute hydrostatic pressure values in the labyrinth. Hydrostatic pressure of the endolymphatic system was recorded in all three semicircular canals. Mean pressure values were 4.06 cmH(2)O ± 0.61 in the posterior, 3.36 cmH(2)O ± 0.94 in the anterior and 3.85 cmH(2)O ± 1.38 in the lateral semicircular canal. Overall hydrostatic pressure in the vestibular organ was 3.76 cmH(2)O ± 0.36. Endolymphatic hydrostatic pressure in all three semicircular canals is the same (p = 0.310). With regard to known endolymphatic pressure values in the cochlea from past studies vestibular pressure values are comparable to cochlear values. Until now it is not known whether the reuniens duct and the Bast's valve which are the narrowest passages in the endolymphatic system are open or closed. Present data show that most likely the endolymphatic system is a functionally open entity.


Assuntos
Deslocamentos de Líquidos Corporais/fisiologia , Pressão Hidrostática , Líquidos Labirínticos/fisiologia , Vestíbulo do Labirinto/fisiologia , Animais , Cóclea/fisiologia , Cobaias , Hidrodinâmica , Valores de Referência , Canais Semicirculares/fisiologia
17.
J Laryngol Otol ; 126(2): 136-41, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22152636

RESUMO

The newly developed use of magnetic resonance imaging of the human inner ear, on a 3 Tesla scanner with intratympanically administered gadolinium, can now reliably distinguish perilymph from endolymph and visually confirm the presence or absence of endolymphatic hydrops. Transtympanic tone burst electrocochleography is an established, and under-utilised evoked response electrophysiological test for hydrops, but it relies on a symptom score to indicate the likelihood of hydrops being present. The current diagnostic criteria for Ménière's disease make no allowance for any in vivo test, making diagnostic errors likely. In this small pilot study of three patients undergoing tone burst electrocochleography, subsequent magnetic resonance imaging confirmed or excluded the hydrops that the electrocochleography predicted. Magnetic resonance imaging of the inner ear is a safe technique that can be performed in conjunction with imaging of the VIIIth cranial nerves. As this report comprised only three patients in a pilot study, rigorous clinical studies are required to define the possible role of magnetic resonance imaging in the diagnosis of Ménière's disease.


Assuntos
Audiometria de Resposta Evocada/métodos , Hidropisia Endolinfática/diagnóstico , Imageamento por Ressonância Magnética/métodos , Doença de Meniere/diagnóstico , Adulto , Idoso de 80 Anos ou mais , Meios de Contraste/administração & dosagem , Erros de Diagnóstico , Orelha Interna , Feminino , Perda Auditiva Neurossensorial/diagnóstico , Humanos , Líquidos Labirínticos , Masculino , Meglumina/administração & dosagem , Meglumina/análogos & derivados , Pessoa de Meia-Idade , Compostos Organometálicos/administração & dosagem , Projetos Piloto , Vertigem/diagnóstico
18.
J Acoust Soc Am ; 130(3): 1441-51, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21895085

RESUMO

A discrete model of cochlear mechanics is introduced that includes a full, three-dimensional, description of fluid coupling. This formulation allows the fluid coupling and basilar membrane dynamics to be analyzed separately and then coupled together with a simple piece of linear algebra. The fluid coupling is initially analyzed using a wavenumber formulation and is separated into one component due to one-dimensional fluid coupling and one comprising all the other contributions. Using the theory of acoustic waves in a duct, however, these two components of the pressure can also be associated with a far field, due to the plane wave, and a near field, due to the evanescent, higher order, modes. The near field components are then seen as one of a number of sources of additional longitudinal coupling in the cochlea. The effects of non-uniformity and asymmetry in the fluid chamber areas can also be taken into account, to predict both the pressure difference between the chambers and the mean pressure. This allows the calculation, for example, of the effect of a short cochlear implant on the coupled response of the cochlea.


Assuntos
Cóclea/fisiologia , Mecanotransdução Celular , Modelos Biológicos , Animais , Membrana Basilar/fisiologia , Implantes Cocleares , Análise de Fourier , Humanos , Líquidos Labirínticos/fisiologia , Modelos Lineares , Pressão
19.
Artigo em Chinês | MEDLINE | ID: mdl-20627054

RESUMO

OBJECTIVE: To visualize the endolymph in Meniere's disease by applying for non-invasive intratympanic gadolinium through eustachian tube and three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D-FLAIR MRI). METHODS: With a 3 Tesla magnetic resonance imaging (MRI) unit, 3D-FLAIR imaging was performed 24 h after intratympanic gadolinium through eustachian tube in seven patients with Meniere's disease. Pure tone test was performed 24 h before and after administered gadolinium. Tympanometry was performed 24 h before, 24 h and 3 months after administered gadolinium. RESULTS: In five patients, the gadolinium could appear in parts of the perilymph inside the inner ear but not in the middle ear and mastoid, moreover, the border between the perilymph and endolymph was visible so that endolymphatic space was clearly shown on 3D-FLAIR imaging. In two patients with endolymphatic hydrops, the perilymphatic space surrounding endolymph was small or disappeared. In two patients, the gadolinium could appear in parts of the middle ear and mastoid but not in the inner ear. No significant changes in pure tone test and tympanometry were noted. CONCLUSIONS: 3D-FLAIR MRI with intratympanic gadolinium through eustachian tube could clearly reveal the visualization of endolymphatic space in Meniere's disease.


Assuntos
Hidropisia Endolinfática/patologia , Imageamento por Ressonância Magnética , Doença de Meniere/patologia , Adulto , Meios de Contraste , Orelha Interna/patologia , Orelha Média/patologia , Feminino , Gadolínio DTPA , Humanos , Imageamento Tridimensional , Líquidos Labirínticos , Masculino , Pessoa de Meia-Idade
20.
J Acoust Soc Am ; 128(6): 3577-84, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21218890

RESUMO

Using conformal mapping, fluid motion inside the cochlear duct is derived from fluid motion in an infinite half plane. The cochlear duct is represented by a two-dimensional half-open box. Motion of the cochlear fluid creates a force acting on the cochlear partition, modeled by damped oscillators. The resulting equation is one-dimensional, more realistic, and can be handled more easily than existing ones derived by the method of images, making it useful for fast computations of physically plausible cochlear responses. Solving the equation of motion numerically, its ability to reproduce the essential features of cochlear partition motion is demonstrated. Because fluid coupling can be changed independently of any other physical parameter in this model, it allows the significance of hydrodynamic coupling of the cochlear partition to itself to be quantitatively studied. For the model parameters chosen, as hydrodynamic coupling is increased, the simple resonant frequency response becomes increasingly asymmetric. The stronger the hydrodynamic coupling is, the slower the velocity of the resulting traveling wave at the low frequency side is. The model's simplicity and straightforward mathematics make it useful for evaluating more complicated models and for education in hydrodynamics and biophysics of hearing.


Assuntos
Cóclea/fisiologia , Líquidos Labirínticos/fisiologia , Mecanotransdução Celular , Modelos Biológicos , Simulação por Computador , Elasticidade , Humanos , Movimento (Física) , Análise Numérica Assistida por Computador , Oscilometria , Pressão , Reologia , Fatores de Tempo , Vibração
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