Article

Relationship of Vestibular Aqueduct and Inner Ear Pressure in M??ni??re???s Disease and the Normal Population

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Abstract

Etiopathogenesis of Ménière's disease has not been resolved. The principal histopathologic finding in this disease is endolymphatic hydrops. The majority of radiologic and histopathologic studies demonstrated a narrow vestibular aqueduct in Ménière's disease. There is no study in the literature investigating the relationship between inner ear pressure and vestibular aqueduct dimensions. Static acoustic compliance is a noninvasive procedure that is thought to measure perilymphatic pressure at the footplate. An increase in mechanical fluid pressure in the inner ear is transmitted to the footplate of the stapes. This causes a reduction in the compliance at the drum. The aim of this study is to investigate the relationship between vestibular aqueduct dimensions and static acoustic compliance in Ménière's disease and the normal population. Prospective study. Forty patients with Ménière's disease and 40 healthy individuals with no otolaryngologic disorders were the subjects of this study. Each group was further divided into two according to static compliance value (normal and low static compliance). In these four groups dimensions of vestibular aqueduct were determined radiologically by high-resolution computerized tomography and correlated with normal and low static acoustic compliance values (normal and high perilymphatic pressure). The results demonstrated that vestibular aqueduct is narrower in patients with Ménière's disease than the normal population. However, there is no relationship between vestibular aqueduct dimensions and inner ear pressure obtained by static acoustic compliance measurements.

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... To verify the hypothesis that increased inner ear pressure causes reduced compliance at the tympanic membrane (TM) and influences TM displacement, recent studies have utilized measurements of static acoustic compliance (SAC) [14][15][16], tympanic membrane displacement (TMD) [17][18][19] and resonant frequency (RF) [20,21]. ...
... The studies by Hall et al. [15] and Levent et al. [16] showed that low static acoustic compliance could be easily observed in patients with Ménière's disease (MD). Yazawa et al. [22] found endolymphatic hydrops in 93% MD patients suggesting an increased inner ear pressure in MD patients. ...
... Yazawa et al. [22] found endolymphatic hydrops in 93% MD patients suggesting an increased inner ear pressure in MD patients. However, a 30% incidence of low static compliance had been observed on normal people and 60% in patients with Ménière's disease in the study of Levent et al. [16], which shows the sensitivity and specificity of the static acoustic compliance to be low. Other studies revealed that tympanic membrane movement was affected by inner ear pressure when it was measured using either microflow [17] or laser Doppler interferometry [18] on human temporal bones. ...
Article
Objective: To investigate middle ear function in children with Large Vestibular Aqueduct Syndrome (LVAS) to explore the feasibility of measuring inner ear pressure using Wideband tympanometry (WBT). Methods: 13 young children with LVAS were recruited. WBT and other audiological measurements i.e., Auditory Steady State Response (ASSR), Auditory Brain Stem Response (ABR), and Distorted Product Otoacoustic Emissions (DPOAE) were performed. Absorbance under ambient and peak pressure were compared with normative data, and analyzed using a one sample t-test. Results: Average absorbance in children with LVAS was significantly lower than normative data under ambient pressure at 1000, 1189, 1296, 2000 Hz and 4000 Hz. Absorbance under peak pressure was also significantly lower at 707, 794, 917, 1000, 1189, 1297, 1498 and 2000 Hz. However, absorbance was higher than standard values above 4000 Hz under ambient and peak pressure. It was also higher under ambient pressure at frequencies below 500 Hz. Conclusion: The special characteristics of middle ear function found in children with Large Vestibular Aqueduct Syndrome (LVAS) indicate that WBT offers a sensitive and non-invasive method to evaluate inner ear pressure indirectly.
... The vestibular aqueduct (VA) is one of the most studied labyrinth structures, with an anatomical and physiological role supposedly important in the genesis of hydrops. It consists of a bony tunnel that contains the duct and part of the endolymphatic sac [1], where the endolymph is absorbed [2]. ...
... Efforts to correlate the radiological visualization and shape of VA with the etiology, diagnosis and treatment of MD have led to confusing and conflicting results. Some authors have described the high incidence of non-radiological visualization and/ or narrowing of VA [2][3][4][5][6][7][8][9][10][11][12][13][14][15] and mastoid with poor pneumatization in patients with MD [4][5][6][13][14][15][16][17][18], however other authors considered these radiological observations as non-specific signs seen in a variety of otological diseases and even in normal ears [19,20]. ...
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Abstract Objectives: To systematize the anatomical study of the vestibular aqueduct using high resolution computed tomography (HRCT) and to evaluate the retrolabyrinthine region in patients with unilateral Ménière’s disease (MD). Methods: The vestibular aqueduct is one of the most studied labyrinth structures in the genesis of endolymphatic hydrops and has a possible anatomic and physiological role in this disease. Twenty patients with unilateral Ménière’s disease and ten normal patients (control group) underwent HRCT of temporal bones. In total 60 ears were analyzed, 20 of them in each of the following groups: GI (ear affected by MD), GII (MD group - ear not affected), GIII (control). The images were analyzed blindly. The vestibular aqueduct was identified and the measurements were acquired in its middle portion and in the external opening. The retrolabyrinth dimension was also measured in these patients. These findings were analyzed and compared between these groups. Results: The vestibular aqueduct was identified in the ears of 95% of GI, 90% of G II and 100% of G III, and measurements of the width of the middle portion and external opening of vestibular aqueduct were analyzed and showed no statistical difference between the three groups. The retrolabyrinthine dimension was similar between groups G I and G II, but significantly higher in G III (G I=G II<G III). Conclusion: It is possible to apply the proposed systematization for the evaluation of the vestibular aqueduct by HRCT. The identification and measurement of vestibular aqueduct width did not show statistically significant differences between affected (GI) and unaffected (GII) ears of patients with Ménière’s disease, nor in relation to the control group (GIII). The retrolabyrinthine dimension was significantly higher in the control group (GIII) compared to that of GI and GII
... Therefore, VA is also putatively regarded as a crucial structure to ensure the circulation between endolymphma and perilympha, which deficiency can impair the nutrition of inner ear cells, the sonic transduction to hairy cells and balance sensation of sensory cells. Clinically, the dilation and constriction of VA cause congenital sensorineural deafness and Meniere disease, respectively (Sennaroglu et al. 2001;Song et al. 2018;B€ achinger et al. 2019). For instance, VA can buffer intracranial pressure by connecting cochlea aqueduct and cerebrospinal fluid, while the buffer capability of an enlarged VA is dramatically decreased (Carlborg and Farmer 1983;Walsh et al. 1999). ...
Article
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Vestibular aqueduct is a precise structure embedded in the temporal bone and plays a key role in the physiological function of inner ear by maintaining the endolymphatic circulation and buffering the impact from intracranial pressure. Although the alterations on the morphology or volume of vestibular aqueduct result in variety of diseases, the approaches of evaluating the condition of vestibular aqueduct are still unsatisfing because the pathological sections utilized for the 3D construction model most likely undergoes morphological changes. In this study, the vestibular aqueduct images obtained by CT scanning were processed by finite element method to construct the 3D model. To assess if this numerical model reflects the actual biomechanical properties of vestibular aqueduct, the fluid-solid coupling calculation was applied to simulate the endolymphatic flow in the vestibular aqueduct. By measuring the dynamics of endolymphatic flow, and the pressure and displacement on round membrane under external pressure, we found the numerical 3D model recapitulated the biomechanical characteristics of the real vestibular aqueduct. In summary, our approach of 3D model construction for vestibular aqueduct will provide a powerful method for the research of vestibular aqueduct-related diseases.
... Conventional 226-Hz tympanometry uses a low-frequency tone to evaluate the changes in mass effect properties of the middle ear, such as ossicular disruption and effusion, but the assessment of stiffness requires the use of higher frequencies [Colletti, 1976]. Sennaroglu et al. [2001] reported low compliance and high impedance in 69% of MD patients and 30% of healthy controls by using conventional tympanometry. ...
Article
Background: Wide-band tympanometry (WBT) was introduced as a beneficial diagnostic test for Ménière's disease (MD) almost 15 years ago. However, an acute episode of MD has not been evaluated by using WBT yet. Objective: To investigate WBT findings in patients with MD during acute attacks. Method: Thirty definite MD patients with unilateral acute low-tone sensorineural hearing loss and aural fullness, and thirty age- and sex-matched control subjects were enrolled prospectively in a tertiary referral center. Ears were divided into three groups as follows: (1) affected ears of MD patients, (2) contralateral ears of MD patients, (3) control ears. Individuals underwent WBT. The resonance frequency (RF), mean absorbance value, mean low- and high-frequency absorbance values (LF-A and HF-A), and double peak width at 2 kHz of conductance tympanometry (2-kHz PW) were assessed. Results: Seventy percent in group 1, 66.7% in group 2, and 78.3% in group 3 demonstrated double peaks at 2 kHz. The mean 2-kHz PW values were 157.52 ± 79.19, 177.40 ± 79.14, and 139.64 ± 87.501 daPa for groups 1, 2, and 3, respectively. There were no significant differences between groups with respect to 2-kHz PW, RF, absorbance, LF-A, and HF-A. Conclusion: This was the first study that evaluated the effects of acute Ménière attacks on WBT findings. An acute Ménière attack was found to have no significant effect on the 2-kHz PW and other variables measured using WBT.
... Hypoplasia of the vestibular aqueduct already appears in the development of the labyrinth before childhood and might have an impact on the aetiology of MD 92 . Numerous radiographic studies by Sennaroglu et al. have demonstrated that the vestibular aqueduct is significantly narrower in the affected ear in patients with MD than the unaffected ear 93 . Any condition that causes narrowing of the vestibular aqueduct and the production of excess endolymph could result in the same symptom complex as patients with MD 30 . ...
Article
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Ménière's disease, a condition first described in the 1800's, has been an advancing area of clinical interest and scientific research in recent decades. Guidelines published by the American Academy of Otolaryngology - Head and Neck Surgery remained nearly static for almost 20 years, although we have certainly expanded our knowledge of the aetiology of the disease since that time. This review of the literature highlights the breadth and detail of the current theories in understanding the pathophysiology of this enigmatic disease. Histopathological specimens providing evidence of many of the aetiologies are presented as well. We aim to provide a centralised and updated resource regarding current and emerging theories for Ménière's disease. © Copyright by Società Italiana di Otorinolaringologia e Chirurgia Cervico-Facciale.
... Fakat endolenf emilimini bozan ve endolenfin birikmesini sağlayan faktörlerin neler olduğu tam olarak bilinmemektedir. Bugüne kadar öne sürülen nedenler arasında viral enfeksiyonlar, diyet, genetik, vasküler faktörler, iyon dengesindeki değişiklikler, immün mekanizmalar, glikoprotein mekanizmasındaki değişiklikler sayılabilir [8][9][10][11]. Endolenfatik hidropsun sebep mi sonuç mu olduğu konusunda farklı görüşler bulunmaktadır. Paparella ve ark. ...
Article
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Meniere’s disease, also known as idiopathic symptomatic endolymphatic hydrops, is an inner ear disease characterized by spontaneous vertigo attacks, fluctuating hearing loss, ear fullness/pressure sensation and tinnitus. Age of onset is often 50-60 years. History and specific audiometric investigations are used in the diagnosis. As definitive diagnosis is only possible with the histopathological examination, nowadays Meniere's disease is currently placed among the diseases whose diagnosis is difficult. In the majority of patients, treatment is medical and additional psychological support is recommended. Surgical treatment may be considered in patients who don’t respond to medical therapy. In this review, pathogenesis, physiology, symptomatology, diagnosis and treatment of Meniere’s disease will be discussed.
... Several previous human temporal bone and imaging studies have reported similar findings in their Meniere's population (as compared with nondiseased controls), including hypoplasia of the vestibular aqueduct; narrowing of the lumen of the endolymphatic duct; hypodevelopment of Trautmann's triangle; the relationship of the position of the posterior fossa dural plate to the endolymphatic sac; aberrant (lateral) displacement of the lateral venous sinus; and smaller external apertures of the aqueduct. 1,5,6,23,[28][29][30][31][32][33] Given these anatomic differences, high-resolution MRI and CT scans could become valuable diagnostic tools in the evaluation of selected patients, especially those with atypical presentations of Meniere's disease. ...
Article
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Objectives/Hypothesis To measure the volume of the endolymph drainage system in temporal bone specimens with Ménière disease, as compared with specimens with endolymphatic hydrops without vestibular symptoms and with nondiseased specimens Study Design Comparative human temporal bone analysis. Methods We generated three-dimensional models of the vestibular aqueduct, endolymphatic sinus and duct, and intratemporal portion of the endolymphatic sac and calculated the volume of those structures. We also measured the internal and external aperture of the vestibular aqueduct, as well as the opening (if present) of the utriculoendolymphatic (Bast's) valve and compared the measurements in our three study groups. Results The volume of the vestibular aqueduct and of the endolymphatic sinus, duct, and intratemporal endolymphatic sac was significantly lower in the Ménière disease group than in the endolymphatic hydrops group (P <.05). The external aperture of the vestibular aqueduct was also smaller in the Ménière disease group. Bast's valve was open only in some specimens in the Ménière disease group. Conclusions In temporal bones with Ménière disease, the volume of the vestibular aqueduct, endolymphatic duct, and intratemporal endolymphatic sac was lower, and the external aperture of the vestibular aqueduct was smaller as compared with bones from donors who had endolymphatic hydrops without vestibular symptoms and with nondiseased bones. The open status of the Bast's valve in the Ménière disease group could be secondary to higher retrograde endolymph pressures caused by smaller drainage systems. These anatomic findings could correlate with the reason that some patients with hydrops develop clinical symptoms, whereas others do not.
... 40 Ménière's disease has previously been associated with a narrowed VA rather than a large VA. [70][71][72][73][74][75][76] However, in 2009, Spiegel and Lalwani 41 reported a family in which one sibling suffered from LVAS and the other had classic Ménière's disease, a finding that led them to presume the existence of a common primary dysfunction of inner ear fluid homeostasis between LVAS and endolymphatic hydrops. They attributed the determining factor for the presentation as endolymphatic hydrops or as LVAS to differences in inner ear membrane compliance. ...
Article
Large vestibular aqueduct syndrome (LVAS) is one of the most common congenital inner ear malformations. LVAS is generally diagnosed via high-resolution computed tomography (CT) as a vestibular aqueduct midpoint greater than 1.5 mm; however, other criteria have recently been proposed. LVAS can be found in isolation as well as in conjunction with both syndromic and nonsyndromic hereditary hearing loss. The typical presentation of LVAS is that of down-sloping hearing loss, oftentimes accompanied by a conductive component, with progressions in hearing loss occurring either spontaneously or paired with a precipitating event. CT and traditional audiometry including bone conduction testing, tympanometry, and acoustic reflex testing should be considered part of a traditional workup for LVAS. Other clinical tools such as magnetic resonance imaging and vestibular function testing, specifically vestibular evoked myogenic potential (VEMP), also have proven useful in identifying this population. This review presents a clinical case of bilateral LVAS and reviews the common clinical presentation of LVAS including diagnostic guidelines, audiometric configuration, vestibular function testing outcomes, and treatment options.
... The radiographic measurements of the cochlear aqueduct5 or vestibular aqueduct 6 are difficult to perform, and they do not correlate well with endolymphatic pressure and, consequently, with Ménière's disease symptomatology. ...
Article
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OBJECTIVE: To evaluate low-frequency masking in the early diagnosis of Ménière's disease. PATIENTS AND METHODS: Thirty-five patients suffering from Ménière's disease were examined. The results were compared with that of 10 patients with normal hearing ears and 40 with noise-damaged ears. All examinations were made by the use of a special instrumentation capable of producing a low-frequency sound signal superimposed with a tone burst. We were able to independently change the amplitudes of the 2 applied signals, as well as the phase lag between them from 0° to 360°. Adjusting the 2 amplitudes and the phase lag, the examined individuals heard 2 sounds, 1 as the masking tone and 1 high-frequency tone superimposed on the low-frequency masking. RESULTS: In normal individuals, the highest masking effect was evident at 250° and the lowest at 360°. A lower masking effect was also evident at 90°. Normal hearing participants had a modulation depth between 20 and 35 dB, while patients with noise damaged ears had an effect about 10 dB and patients with Ménière's disease had one closer to 0 dB. The instru-mentation and method presented in this article show a relatively good clinical diagnostic accuracy because it is capable of diagnosing the basilar membrane stiffness on an almost null modulation depth. Test sensitivity is near 70%. CONCLUSION: The developed instrumentation and method can distinguish and diagnose the early stages and acute recurrences of Ménière's disease. This may lead to a further study of the results of low-frequency masking on the anterior labyrinth in research centers worldwide, in order to reinforce the diagnostic accuracy and strength of this newly developed diagnostic method.
... The vestibular aqueduct (VA) is a small bony canal of labyrinthine capsule linking the medial wall of the vestibule of the inner ear to the posterior part of the petrous temporal bone. It houses the endolymphatic duct and includes part of the endolymphatic sac [1] . ...
Article
Full-text available
OBJECTIVE: To assess the clinical significance of vestibular aqueduct (VA) width measurement on high resolution CT images in pediatric patients with sensorineural hearing loss (SNHL). MATERIALS AND METHODS: 34 pediatric patients with sensorineural hearing loss (Group I) and 42 controls without SNHL (Group II) underwent otorhinolaryngological, otoneurological examinations, full audiological, sinusoidal harmonic acceleration evaluation and high resolution CT scan of temporal bone. VA width was measured at coronal and axial planes (at both midpoint and opercular levels). RESULTS: In control group, vestibular aqueduct mean width was [0.80 and 0.71] at right and left midpoint, [1.6 mm] at opercular level and (1.4 mm at right and 1.5 at left side) on coronal image. Enlarged vestibular aqueduct was in nineteen (55.9%) patients with SNHL. VA mean width was [2.62 and 2.35] at midpoint, [3.31 and 3.27 mm] at opercular level, and (2.8 mm and 3.24) on coronal images at right and left sides respectively. Sinusoidal Harmonic Acceleration (SHA) was abnormal in (47%) of children with SNHL; (68.8%) of them had enlarged VA. CONCLUSION: VA is enlarged; if it exceeded (1.2), (2.1) and (1.5) mm at midpoint, opercular level and on coronal images respectively. Incidence of enlarged vestibular aqueduct is higher with severe to profound hearing loss. Incidence of gain abnormality in rotational testing is common in patients with enlarged vestibular aqueduct. Most children with enlarged vestibular aqueduct have combined audio-vestibular dysfunction
... É um canal ósseo da cápsula labiríntica que vai da parede medial do vestíbulo à superfície dorsal do osso petroso. Contém em seu interior o ducto endolinfático e uma parte do saco endolinfático, onde ocorre a reabsorção da endolinfa (1) . ...
Article
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OBJETIVO: Sistematizar a avaliação do aqueduto vestibular por tomografia computadorizada de alta resolução (TCAR) em pacientes com doença de Ménière unilateral e comparar com um grupo-controle. MATERIAIS E MÉTODOS: Selecionamos 20 pacientes com doença de Ménière unilateral, segundo critérios da Academia Americana de Otorrinolaringologia – Cirurgia de Cabeça e Pescoço, e um grupo-controle composto por dez indivíduos com avaliação auditiva normal, totalizando 60 orelhas, distribuídas igualmente em três grupos: grupo I – doença de Ménière, orelha comprometida; grupo II – doença de Ménière, orelha não-comprometida; grupo III – controle. Submetemos os pacientes à TCAR de ossos temporais. O estudo das imagens foi feito de modo cego, procurando avaliar a visibilidade da porção descendente do aqueduto vestibular. Os dados obtidos foram correlacionados com os respectivos grupos. RESULTADOS: A visualização do aqueduto vestibular foi de 95% no grupo I, 90% no grupo II e 100% no grupo III. CONCLUSÃO: É possível sistematizar a avaliação por TCAR do aqueduto vestibular, com aquisição axial, usando a mesma técnica radiológica, conhecimento anatômico e seguimento seqüencial das estruturas da orelha interna. Com esta sistematização houve alta taxa de visualização do aqueduto vestibular, sem diferença estatisticamente significante entre os grupos.
... Pappas et al. [8] observed that in 29 patients, with large VA syndrome, aging between 4 months and 36 years, the external opening of the vestibular aqueduct presented 0.95 mm of width. Sennaroglu et al. [9] observed that in 40 normal patients, aging between 19 and 60 years, the external opening of the vestibular aqueduct presented 1.5 mm of width. Despite the criteria used, the mean width of the external opening of the vestibular aqueduct presented in this study is not very close to that quoted literature. ...
Article
Objective: In the last two decades, advances in the computerized tomography (CT) field revise the internal and medium ear evaluation. Therefore, the aim of this study is to analyze the morphology and morphometric aspects of the vestibular aqueduct on the basis of computerized tomography images (CTI). Material and method: Computerized tomography images of vestibular aqueducts were acquired from patients (n = 110) with an age range of 1–92 years. Thereafter, from the vestibular aqueducts images a morphometric analysis was performed. Through a computerized image processing system, the vestibular aqueduct measurements comprised of its area, external opening, length and the distance from the vestibular aqueduct to the internal acoustic meatus. Results: The morphology of the vestibular aqueduct may be funnel-shaped, filiform or tubular and the respective proportions were found to be at 44%, 33% and 22% in children and 21.7%, 53.3% and 25% in adults. The morphometric data showed to be of 4.86 mm 2 of area, 2.24 mm of the external opening, 4.73 mm of length and 11.88 mm of the distance from the vestibular aqueduct to the internal acoustic meatus, in children, and in adults it was of 4.93 mm 2 , 2.09 mm, 4.44 mm, and 11.35 mm, respectively. Conclusions: Computerized tomography showed that the vestibular aqueduct presents high morphological variability. The morphometric analysis showed that the differences found between groups of children and adults or between groups of both genders were not statistically significant.
... (3) In the reconstructed 3-dimensional CT images, the external aperture of the VA fenestra in patients with Mé niè re's disease was hypoplastic and significantly smaller than that in normal individuals [22][23][24]. (4) In patients with bilateral Mé niè re's disease, the size of the VA in both ears was significantly smaller than that in the case of normal individuals, which was determined using CT images [23,25,26]. Most of these reports showed that the VA of affected and nonaffected ears in patients with Mé niè re's disease was smaller than that in normal individuals. ...
Article
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Previous studies, in which the vestibular aqueduct (VA) was determined using axial CT, have indicated that the VA sizes in patients with Ménière's disease were smaller than those in the subjects of the control group and that 25-35% of ears with Ménière's disease were "non-visible type." In this study, in addition to obtaining the axial size, we measured the VA size along the vertical plane by using vertical multiplanar reconstruction (MPR) images. The VA size of both ears of patients with unilateral Ménière's disease (n=34) and of subjects of the control group (n=30) was measured by using the vertical MPR and the axial CT images. The VA size was measured along the axial and vertical planes in all subjects. The parameters measured on the axial image of the VA correlated with each other; however, the parameters on the vertical MPR image did not correlate with those on the axial image. Values of parameters in the affected and nonaffected ears with Ménière's disease tended to be smaller than those in the control ear. The external aperture areas of the VA fenestra of the affected and nonaffected ears of patients with Ménière's disease were significantly smaller than that for the control ears. Our findings suggest that the vertical parameters of the VA yield information that is independent of that provided by the axial parameters. In both ears of patients with unilateral Ménière's disease, the VA tended to be thinner than those in the control ear.
... Pappas et al. [8] observed that in 29 patients, with large VA syndrome, aging between 4 months and 36 years, the external opening of the vestibular aqueduct presented 0.95 mm of width. Sennaroglu et al. [9] observed that in 40 normal patients, aging between 19 and 60 years, the external opening of the vestibular aqueduct presented 1.5 mm of width. Despite the criteria used, the mean width of the external opening of the vestibular aqueduct presented in this study is not very close to that quoted literature. ...
Article
In the last two decades, advances in the computerized tomography (CT) field revise the internal and medium ear evaluation. Therefore, the aim of this study is to analyze the morphology and morphometric aspects of the vestibular aqueduct on the basis of computerized tomography images (CTI). Computerized tomography images of vestibular aqueducts were acquired from patients (n=110) with an age range of 1-92 years. Thereafter, from the vestibular aqueducts images a morphometric analysis was performed. Through a computerized image processing system, the vestibular aqueduct measurements comprised of its area, external opening, length and the distance from the vestibular aqueduct to the internal acoustic meatus. The morphology of the vestibular aqueduct may be funnel-shaped, filiform or tubular and the respective proportions were found to be at 44%, 33% and 22% in children and 21.7%, 53.3% and 25% in adults. The morphometric data showed to be of 4.86 mm(2) of area, 2.24 mm of the external opening, 4.73 mm of length and 11.88 mm of the distance from the vestibular aqueduct to the internal acoustic meatus, in children, and in adults it was of 4.93 mm(2), 2.09 mm, 4.44 mm, and 11.35 mm, respectively. Computerized tomography showed that the vestibular aqueduct presents high morphological variability. The morphometric analysis showed that the differences found between groups of children and adults or between groups of both genders were not statistically significant.
Article
Full-text available
Objective: Computed tomography (CT) images of the temporal bone of large vestibular aqueduct syndrome (LVAS) patients were used to establish 3D numerical models based on the structure of the inner ear, which are, in turn, used to construct inner ear fluid-solid coupling models. The physiological features and pathophysiology of LVAS were analyzed from a biomechanical perspective using finite element analysis. Methods: CT images of the temporal bone were collected from five children attending the Second Hospital of Dalian Medical University in 2022. The CT images were used to build 3D models of the inner ear containing the vestibular aqueduct (VA) by Mimics and Geomagic software, and round window membrane models and fluid-solid coupling models were built by ANSYS software to perform fluid-solid coupling analysis. Results: By applying different pressure loads, the deformation of the round window membranes occurred, and their trend was basically the same as that of the load. The deformation and stress of the round window membranes increased with the increase in load. Under the same load, the deformation and stress of the round window membranes increased with the expansion of the midpoint width of the VA. Conclusion: CT images of the temporal bone used clinically could establish a complete 3D numerical model of the inner ear containing VA. Fluctuations in cerebrospinal fluid pressure could affect inner ear pressure, and VA had a limiting effect on the pressure from cerebrospinal fluid. The larger the VA, the smaller the limiting effect on the pressure.
Article
Objective: Large vestibular aqueduct syndrome (LVAS) is one of the etiology of hearing loss. Clinically, we observed that the VA size of patients with idiopathic sudden sensorineural hearing loss (ISSNHL) did not meet the diagnostic criteria of VA enlargement, but there were individual variations. Through this study, we want to understand the VA development and explore its risk for suffering from ISSNHL. Methods: 74 patients with ISSNHL were retrospectively reviewed in our department from June 2018 to September 2021. Meanwhile, 57 people with no ear diseases were randomly selected as the control group. All their clinical information were systematically collected. The axial thin-slice CT images of temporal bone were used to observe and measure the VA in ISSNHL and controls. ISSNHL were classified as different types and grades according to pure tone audiometry and the degree of hearing loss, respectively. Logistic regression analysis was adopted to evaluate the risk factors of different types and grades of ISSNHL. Results: The operculum morphology could be funnel-shaped, tubular and invisible, but they had no statistical difference in the morbidity of ISSNHL. The operculum width of the affected sides in the case group was significantly wider than that of the matched sides in the control group (0.84±0.35mm vs 0.68±0.34mm, p=0.009), but the midpoint width had no statistical difference (p=0.447). The operculum width was an independent risk factor for the total hearing loss type (p=0.036, OR=4.49, 95% CI=1.10-18.29), moderate (p=0.013, OR=17.62, 95% CI=1.82-170.95) and profound (p=0.031, OR=4.50, 95% CI=1.14-17.67) grade of ISSNHL. Hypertension was an independent risk factor for the severe grade (p=0.004, OR=12.44, 95% CI=2.19-70.64) of ISSNHL. Both the operculum width (p=0.048, OR=7.14, 95% CI=1.02-50.26) and hypertension (p=0.014, OR=6.73, 95% CI=1.46-30.97) were the risk factors for the flat type of ISSNHL. The midpoint width of the VA, gender, age, diabetes mellitus, hyperlipidemia, and plasma fibrinogen concentration had no significant effect on the risk for suffering from ISSNHL. Conclusion: The development of the VA operculum is a risk factor for some types and grades of ISSNHL. Hypertension remained a risk factor for ISSNHL.
Article
Objective: To determine the relationship between radiographic temporal bone anatomy of patients with Menière's disease in medically and surgically managed populations versus controls. Study design: Retrospective chart review. Setting: Two tertiary referral centers. Patients: Adults older than 18 years with Menière's disease treated with endolymphatic sac decompression (ESD) or medical management (non-ESD) versus controls. Interventions: Magnetic resonance imaging and computed tomography imaging studies of the temporal bones were reviewed by blinded radiologists. Main outcome measures: Radiographic temporal bone dimensions were measured in Menière's disease and control patients. Age, sex, symptoms, audiogram data, academy classification of Menière's disease, and follow-up were recorded. Statistical analysis was performed to compare outcome measures across groups and demographics. Results: A total of 90 imaging studies were reviewed (ESD = 22; non-ESD = 30; control = 38). ESD and non-ESD groups had similar pure-tone averages (33.9 ± 20.6 versus 41.6 ± 22.6 dB HL; p = 0.21) and frequency of definite Menière's disease (59.1% versus 53.3%; p = 0.68). There was no significant trend between groups for any measurement. One nonsignificant trend existed in mean vestibule length, increasing from the control (5.45 ± 0.54 mm), non-ESD (5.80 ± 0.97 mm), and ESD (5.94 ± 0.81 mm) group. In a combined Menière's group, mean vestibule length was significantly greater than controls (5.86 ± 0.89 versus 5.45 ± 0.54 mm; p = 0.008) and mean vestibule width significantly less (2.99 ± 0.46 versus 3.19 ± 0.39 mm; p = 0.024). Conclusion: Medical and surgical Menière's patients were similar utilizing academy classification. There was no significant trend between medical and surgical Menière's patients versus controls for any measurement. In a combined Menière's group, the longer and narrower vestibule anatomy may suggest an anatomical basis for endolymphatic hydrops.
Article
Background: The pathogenesis of Meniere disease (MD) has not been fully understood. According to the widely accepted theory, imbalances due to overproduction and/or impaired absorption of endolymph may cause endolymphatic hydrops, which is the hallmark pathological finding in MD. Some developmental temporal bone abnormalities may impair endolymph circulation and absorption, and these abnormalities could be a part of MD pathophysiology. However, structural features of the temporal bone cannot explain MD pathophysiology definitively. The authors aimed to determine the length and width of the endolymphatic duct (ED) along with jugular bulb (JB) abnormalities in MD patients and normal controls using high-resolution computed tomography, and to discuss the results supporting and opposing endolymphatic hydrops based on the data obtained. Methods: Thirty-six ears of 18 patients with unilateral MD and 34 ears of 17 normal subjects were enrolled. Jugular bulb abnormalities and ED dimensions were evaluated in 3 groups: affected and unaffected ears of MD patients, and healthy controls. The ED dimensions and JB abnormalities were evaluated with high-resolution computed tomography. Results: The ED was found to be significantly shorter and narrower in the affected ears of the MD patients than in the healthy control group. In addition, more JB abnormalities were detected in the affected ears of the MD patients than in the healthy control group. However, there was no difference between the affected and unaffected ears of the MD patients. Conclusion: Structural ED abnormalities and JB abnormalities may be predisposing factors for the development of Meniere disease, but cannot fully explain MD pathophysiology.
Article
The objective of the present study was to evaluate the cochlear aqueduct (CA) in Meniere's disease (MD) and to disclose radiological differences of CA between MD and non-MD patients by means of high-resolution computed tomography (HRCT) and high-resolution magnetic resonance imaging (HRMRI). Radiological data of 86 ears of MD patients which were separated into 52 ears of diseased side group (MD-D group) and 34 ears of contralateral non-affected side group of unilateral MD (MD-ND group), 27 ears of patients with sensorineural hearing loss (SNHL group) and 56 ears of patients with somatoform dizziness and normal hearing (control group) were analyzed retrospectively. The bony type of CA, the bony length of CA, and the bony width of CA medial orifice was measured in HRCT. The visibility of CA in HRMRI was scored. Fluid length in CA and fluid width in medial orifice were measured in HRMRI. Data were compared between MD-D, MD-ND, SNHL, and control group. There were no significant differences in the bony type of CA, bony length of CA, bony width of CA medial orifice, and fluid width of CA medial orifice between MD-D, MD-ND, SNHL and control group (p > 0.05). However, CA fluid length of MD-D (5.13 ± 1.88 mm) and of MD-ND group (5.44 ± 1.81 mm) was significantly shorter than fluid length of SNHL (6.90 ± 1.55 mm) (p < 0.001, p = 0.001) and of control group (7.43 ± 1.24 mm) (p < 0.001, p < 0.001). The ratio between CA fluid length and CA bony length was the smallest in MD-D group (0.403; p = 0.009). CA bony dimensions of affected ears of MD are normal, but CA fluid length is decreased.
Article
Selected patients with Meniere's disease (MD) show an improvement of disability from vertigo after transtympanic ventilation tube insertion, although an effect on vestibular function is not seen if ipsilateral middle ear pressure lower than -50 daPa is used as a selection criterion. Transtympanic ventilation tube insertion as a treatment option for MD has been reported but its results have been controversial. So far, no investigations on vestibular function in patients with MD after tube insertion have been carried out. Twenty-two patients with unilateral MD who were intractable to medical treatment and who had an ipsilateral middle ear pressure lower than -50 daPa received a transtympanic ventilation tube. Vestibular evoked myogenic potentials (VEMPs) and sinusoidal harmonic acceleration (SHA) testing were recorded pre- and postoperatively and were compared. Most patients (68.2%) reported an improvement of vertigo. Before surgery 63.6% of patients did not show VEMPs, whereas vestibulo-collic reflexes were measured in 36.4% of all cases compared with 68.2% of patients without and 31.8% with recorded VEMPs after surgery. No statistically different findings in gain and phase lag of SHA testing were seen postoperatively compared to preoperative findings.
Article
There exist 3 communication routes between the intracranial space and the inner ear, the vestibular aqueduct, the cochlear aqueduct, and the internal auditory canal. They possess a key role in inner ear pressure regulation and fluid homeostasis and are related to inner ear diseases. Relevant literature was reviewed, and the current knowledge of the anatomy, physiologic importance, and relations to inner ear diseases were described. Pathologic communication routes such as semicircular canal dehiscence syndrome were highlighted as well. Abnormalities in all 3 communication routes may predispose or be the cause of distinct inner ear pathologic condition and involved in other cochlear and vestibular syndromes, in which their role is not completely clear. The increasing knowledge of the underlying mechanisms encourages promising approaches for possible intervention in the future.
Article
To assess the effect of inner ear pressure on middle ear impedance in patients with large vestibular aqueduct syndrome (LVAS). Data from admittance tympanometry and multifrequency tympanometry on 8 LVAS patients and control subjects were studied. Static acoustic compliance (SAC) values for the ears with stable sensorineural hearing loss (SNHL) were within the limits of the mean values of control groups except for two ears. The resonance frequency (RF) values of the ears with stable SNHL were lower than the mean values of control groups except for three ears. SAC values for the two ears with fluctuating SNHL were lower and the RF values were higher than the mean values of control groups. Decreased SAC values and increased RF values found in the ears with fluctuating SNHL might be an indirect indicator of increased inner ear pressure, while low RF values in the ears with stable SNHL might reflect the decreased inner ear impedance.
Article
The purpose of the study was to obtain reference values for the sizes of anatomical structures of the inner ear on computed tomography (CT) images and to compare these values with those obtained from patients with Menière's disease. CT images of the temporal bone of 67 patients without inner ear pathology and 53 patients with Menière's disease have been evaluated. CT was performed in the sequential mode (1-mm slice thickness, 120 kV, 125 mA). Anatomical structures, such as the length and the width of the cochlea and of the vestibule, the height of the basal turn, the length and the width of the cochlear, the vestibular and the singular aqueduct and the internal auditory meatus and the diameter of the semicircular canals, were measured, using a dedicated postprocessing workstation. Reference values from the control group could be obtained. In the patients with Menière's disease, the length and the width of the vestibular aqueduct were smaller, compared with the values from the control group. The values obtained from the control group can serve as reference values for adult patients. The different sizes of anatomical structures of the control group and of patients suffering from Menière's disease suggest that functional impairment might be related to subtle morphological changes.
Article
Full-text available
The acoustic impedance at the eardrum and the cochlear microphonic potential at constant sound pressure level at the eardrum were measured in anesthetized cats and rabbits. It was found that the inverse of the impedance (admittance) and the cochlear microphonic potential at constant sound pressure are proportional over a large frequency range. In addition, the effects of opening of the middle-ear cavities and of variation of the air pressure in the cavity, as well as of activity of the middle-ear muscles were studied. In further experiments, the impedance of the eardrum itself and of the middle ear with the cochlea disconnected was measured.
Article
A model study on human temporal bones was performed. A microflow method was used in order to assess the possibility of making indirect recordings of changes in the inner ear pressures. Changes in the peri-lymphatic pressure were recorded as displacements of the tympanic membrane, the stapedius reflex being artificially elicited by forces applied briefly to the stapedius tendon. Changes in the perilymphatic pressures in the range of ±15 cm H2O affected the position of the tympanic membrane and the “stapedius reflex response”. The microflow method used seems suitable for the clinical recording of changes in the intralabyrinthine pressure.
Article
Das Ziel der klinischen Anwendung der TMD-Technik (tympanic membrane displacement technique) ist es, nicht-invasiv intracochleäre Druckveränderungen zu erfassen. Deshalb werden in der vorliegenden Arbeit die im anfallsfreien Intervall zu erhebenden TMD-Meßwerte (± Vm, mittlere Trommelfellauslenkung) von Patienten mit M. Ménière, fluktuierender Tieftonschwerhörigkeit bzw. rezidivierenden, peripher-vestibulären Schwindelattacken beschrieben. Die Ménière-Patienten in Frühstadien der Erkrankung wiesen zwischen den Anfällen statistisch nicht-signifikante Unterschiede in der mittleren Trommelfellauslenkung (± Vm) als erfaßter TMD-Meßparamter im Vergleich zu ohrgesunden Kontrollen auf. Erst nach mehreren Jahren Erkrankungsdauer und einem Hörverlust größer als 30 dB pantonal zeigt sich ein signifikanter Unterschied zu altersrelationierten Kontrollen, der durch eine Negativierung von Vm (Zunahme von - Vm) gekennzeichnet ist und Zeichen einer intracochleären Druckerhöhung zu sein scheint. Damit geht ein - durch Lagerungsproben während der Messung - nachweisbarer, funktioneller Verschluß des Aquaeductus Cochleae, d.h. des Verbindungsweges zwischen Perilymph- und Liquorraum, einher. Einen Patienten konnten wir vor, während und nach einem akuten Ménière-Anfall als Zufallsbefund untersuchen. Der Verlauf der TMD-Registrierung zeigt an, dass (ausgehend von Vm = + 30 nl, gemessen im anfallsfreien Intervall) am erkrankten Ohr eine intracochleäre Druckzunahme (max. Vm = - 138 nl, 40 min nach Einsetzen des akuten Anfalls) auftrat, die sich jedoch bereits vor Ende des Anfalls bei noch bestehenden Schwindelbeschwerden dem Ausgangswert nahezu angeglichen hatte (Vm = + 19 nl). Das gesunde Ohr zeigte während des Anfalls keine Veränderungen der TMD-Meßwerte. Auffällige Veränderungen ließen sich auch beim Glyzerol-(Klockhoff-) Test nachweisen, dem 6 Patienten mit einem klassischen M. Ménière unterzogen wurden. In enger zeitlicher Kopplung (15 min nach Einnahme) erkennt man mit der Verbesserung des Hörvermögens im Reintonaudiogramm bei positivem Testausfall auch ein Nachlassen des intracochleären Druckes (zunehmende Positivierung von Vm), das statistisch signifikant unterschiedliche TMD-Meßwerte (± Vm) zwischen erkranktem und gesundem Ohr beim Patienten ergab. Die TMD-Methode eignet sich nach unseren Erfahrungen zur differentialdiagnostischen Abklärung von Schwindelbeschwerden bzw. unklaren Tieftonhörstörungen im Rahmen der neurootologischen und audiologischen Diagnostik. Summary The tympanic membrane displacement technique (TMD) is aimed at evaluating intracochlear and intracranial pressure changes non-invasively. Therefore, the present paper describes the findings in patients with Ménière's disease where an increase in volume of the endolymphatic spaces is discussed. It should be investigated to which extent a change in the intracochlear pressure corresponds to different stages of the disease. It could be described that the intracochlear pressure does change over a certain period of persisting Ménière's, but that there is no extensive increase in intracochlear pressure between the attacks. The glycerol test as well as the acute attack (case report on one patient) are, however, characterised by distinct patterns. The same holds true for the late-stage Ménière's. It could be demonstrated that the functional patency of the cochlear aquaeduct in patients with long-term Ménière's history is reduced. This finding is surprising and should be investigated further. In essence, the TMD technique enables to better characterise Ménière patients, but it should not be a tool of routine diagnosis of the disease. In some audiological patients, it can also be beneficially applied (10).
Article
Über den Aquaeductus Cochleae stehen die intrakraniellen Flüssigkeitsräume in direkter Verbindung mit der Perilymphe des Innenohres und über die Reissner'sche Membran auch mit der Endolymphe. Veränderungen des intrakraniellen Druckes können über den Aquaeductus Cochleae auf die Innenohrflüssigkeiten übertragen werden. Neuerdings steht der von R. Marchbanks entwickelte „Tympanic Membrane Displacement Analyser (TDA)” zur Verfügung, ein Meßsystem, mit dem nach Angaben des Entwicklers auf nicht-invasivem Weg, durch Messung der bei der Auslösung eines Stapediusreflexes entstehenden Trommelfellbewegungen, Druckveränderungen in den intrakraniellen und intracochleären Flüssigkeitsräumen erfaßt werden können. Es werden die Meßergebnisse von 20 Normalpersonen im Vergleich zu 29 Patienten mit einseitigen Innenohrerkrankungen vorgestellt. Es konnten keine Unterschiede der Meßergebnisse zwischen Patienten mit M. Ménière, Patienten mit Hörsturz und Normalpersonen festgestellt werden. Summary Intracranial pressure is transmitted to the perilymph of the cochlea via the cochlear aquaeduet and via Reissner's membrane to the endolymph. The “Tympanic Membrane Displacement Analyser (TDA)” is a new device that may be a useful non-invasive method to show intracranial and intracochlear pressure changes indirectly measured by tympanic membrane displacement during stapedial reflex contraction. The TDA was utilised in 20 normal persons and in 29 patients with unilateral diseases of the inner ear. No significant differences in the tympanic membrane displacement were found between patients with sensorineural hearing loss, patients with Ménière's disease, and normal persons.
Article
• A controversy exists concerning whether or not roentgenographic narrowing or nonvisualization of the vestibular aqueduct is a specific sign for Meniere's disease. Of 190 ears that were evaluated, abnormal aqueducts were seen in 42.9% of ears with Meniere's disease, 45.4% of contralateral, noninvolved ears from patients with Meniere's disease, 41.3% of ears with diseases other than Meniere's disease, 30.4% of ears with no disease, and 51.6% of normal ears. Narrowing or nonvisualization of the vestibular aqueduct is a nonspecific roentgenographic sign that is seen in diseased, as well as in normal ears, and should not be used to make a diagnosis of Meniere's disease. Indications for polytomography in Meniere's disease include (1) preoperative evaluation of the aqueduct prior to endolymphatic shunt procedures and (2) exclusion of acoustic neurinomas or other organic causes of vertigo. (Arch Otolaryngol 105:91-98, 1979)
Article
In this study an electroacoustic impedance bridge and an X–Y recorder were used to measure maximum compliance (Cm) in 53 patients symptomatic of Meniere's disease in only one ear. Various parameters of Meniere's disease were investigated by comparing Cm values between ears. The parameters which were investigated included: (1) Meniere's disease; (2) the symptom of fullness; (3) the length of disease; and (4) the degree of hearing loss. The data were interpreted as demonstrating that there were differences in Cm which were indicative and consistent with what would be expected for mechanical changes in the inner ear associated with Meniere's disease.
Article
An attempt is made to demonstrate that 3 symptoms found in patients with endolymphatic hydrops can be explained merely on the basis of cochlear hydrodynamics: the low frequency hearing loss, diplacusis, and the occurrence of even harmonic distortion. Given the structural make up of the inner ear, these are the events that must happen when the endolymphatic perilymphatic fluid balance is altered. At least the low frequency response changes were observed in animal experiments using the cochlear microphonic responses as an indicator. As for the 3 remaining symptoms, loss of speech discrimination, recruitment, and tinnitus, it is believed that the combination of distortion, low frequency hearing loss, and tinnitus may well affect the understanding of speech, although distortion as such has little effect upon speech intelligibility, as experiments at the Harvard psychoacoustic laboratory indicated many years ago. Finally, tinnitus and recruitment are phenomena that cannot be explained on the basis of the cochlear membrane phenomena described. Their causes must be sought in hair cell malfunction, possibly mediated by the endolymphatic perilymphatic pressure difference. The upper poles of the hair cells face endolymph, whereas their bodies in the spaces of Nuell are exposed to perilymph, as the basilar membrane is not a barrier for fluid exchange. As with all the other symptoms, these are transient and can therefore not be regarded as actual sensorineural phenomena.
Article
High resolution transverse axial CT encompassing the lateral semicircular canal was used to study the visualization of the vestibular aqueduct and to measure the minimum distance between the posterior semicircular canal and the posterior petrous surface (P-P distance) in Meniere's disease and chronic otitis media. The results indicate that the development of the bone between the posterior semicircular canal and the posterior petrous surface, which usually contains the endolymphatic sac, is significantly poorer in affected ears than in nonaffected ears in unilateral Meniere's disease, and much poorer than in chronic otitis media.
Article
We used light microscopy and computerized graphic reconstruction techniques to examine the endolymphatic duct and sac in 20 pairs of bones from patients with Menière's disease and 21 bones from controls. The diameters of the endolymphatic duct and the proximal portion of the vestibular aqueduct were significantly smaller in Menière's disease ears than in controls. Graphic reconstructions showed the Menière's sacs to be smaller and to have fewer tubular epithelial structures in the intraosseous portion than in the control ears. The median volume of the sac in the Menière's disease side was substantially lower than in the contralateral ear. The width of the external aperture of the vestibular aqueduct was significantly smaller in Menière's disease ears than in controls. These findings indicate that the size not only of the vestibular aqueduct but also of the sac is reduced in Menière's disease. The results may suggest that the endolymphatic sac is pathologically changed in Menière's disease and that a reduced resorptive capacity of a small endolymphatic sac could result in endolymphatic hydrops.
Article
Observation of the external aperture of the vestibular aqueduct was hitherto possible only in cadavers or dry temporal hones; however, by applying three-dimensional surface reconstruction imaging, it is now possible to observe solid-looking images of this structure in living humans. When the width of the external aperture of the vestibular aqueduct was measured in 58 people, it was found to be significantly narrower in the affected ears of patients with Meniere’s disease than in normal ears. © The American Laryngological, Rhinological & Otological Society, Inc.
Article
The coexistence of otosclerosis and endolymphatic hydrops in the temporal bone have been described; however, the mechanism for the development of endolymphatic hydrops in otosclerosis remains unknown. Among 128 temporal bones with otosclerosis, involvement of the vestibular aqueduct by otosclerosis was observed in four temporal bones from two patients. In all four, the vestibular aqueduct was filled with active otosclerotic foci; the lumen of the endolymphatic duct and sac was narrowed as a result of fibrosis, and endolymphatic hydrops, more severe in the pars inferior than the pars superior, was observed. Collapse of the ductus reuniens and dilated saccule was seen in three temporal bones. Our study indicates that otosclerotic obstruction of the vestibular aqueduct may create a disturbance of the outflow and/or absorption of endolymph, leading to the development of endolymphatic hydrops and Meniere's disease, thus supporting the theory of longitudinal flow of endolymph.
Article
The patency of the cochlear aqueduct is a key factor in intra-cochlear hydromechanics. If patent, the cerebrospinal fluid (CSF) provides the reference pressure for the perilymph and also to a large extent the endolymph, since Reissner's membrane can only withstand a relatively small pressure differential. The aqueduct often becomes sealed as a natural process of ageing. In this instance the reference pressure is from a source, its position unknown, within the boundaries of the cochlea itself. Relatively large and rapid changes in the cerebrospinal fluid pressure may result from everyday events such as coughing (ca. 175 mm saline) and sneezing (ca. 250 mm saline). The resistive nature of the cochlear aqueduct and the mechanical compliance of the cochlear windows are probably important factors in limiting the amount of stress, and therefore possible damage, which may occur to the cochlea and cochlear windows for a given pressure change within the CSF system. A narrow aqueduct and compliant cochlear windows reduce the risk of structural damage. In practice, this should mean that the risk of structural damage will be increased by any process which reduces the compliance of one or both of the cochlear windows, for example, extremes of middle ear pressure perhaps brought about by Eustachian tube dysfunction or rapid barometric pressure changes. Techniques are now available which provide non-invasive indirect measures of perilymphatic pressure and CSF-perilymphatic pressure transfer. The tympanic membrane displacement measurement technique has been used to provide reliable measures of perilymphatic pressure and CSF-perilymphatic pressure transfer on an individual subject basis.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
From a series of patients undergoing routine radiographic examination, 112 temporal bones with a high jugular fossa were selected. Among these, 43 jugular bulb diverticula were found. The structures affected by a high fossa or diverticulum were recorded and correlated to the clinical symptoms of the patient. The vestibule was suspected to be affected in five patients. Two of these patients had tinnitus and vertigo, and three had hearing loss. In one of the latter the hearing loss was most marked in the supine position. The cochlea was close to the fossa in three patients, all of whom had tinnitus. Four patients had a defect of the posterior semicircular canal. One of them lost his hearing after a severe fit of coughing, became unsteady and showed signs of a fistula. The internal acoustic meatus and the mastoid portion of the facial canal were affected in two and four patients, respectively, who had no recorded symptoms. Twelve of 34 patients with Menière's disease and a high jugular fossa on the side of the diseased ear had a dehiscence of the vestibular aqueduct caused by the fossa or diverticulum, compared with nine of 58 patients in the unselected material. For comparison and demonstration of topographic relationships, 58 casts of unselected radiographed temporal bone specimens with high jugular fossae or diverticula were investigated. In patients with a high jugular fossa or jugular bulb diverticulum, tomographic assessment may be of value.
Article
The primary histologic correlate of Menière's disease is endolymphatic hydrops. From this, many investigators have postulated the existence of endolymphatic hypertension, although there have been no measurements published to substantiate this concept. Seventy guinea pigs, surgically treated with right endolymphatic duct obstruction, were later assessed by use of a micro-electrode technique that measured their endolabyrinthine hydrostatic pressures. For 21 of these animals, the pressures of both scala tympani (Pst) and scala media (Psm) of both ears of each animal were successfully measured. Similar measurements were made in a control group of 25 guinea pigs that had not undergone any previous surgery. For normal ears--as well as those with hydrops-pressure differences between perilymph and endolymph (Psm - Pst) varied around 0 +/- 2.0 mm Hg. When only the right (obstructed) ears were considered, there appeared to be a slight, relative pressure elevation (p less than 0.05) in scala media during the first 7 days after endolymphatic duct obstruction-and in those ears with EP, less than 70 mV. The magnitude of this pressure difference that can be attributed to the state of endolymphatic hydrops-and not to natural variability-is calculated (within 95% confidence limits) to be less than 0.5 mm Hg.
Article
Histological evaluations were made of the degree of pneumatization and thickness of the petrous bone surrounding the vestibular aqueduct, and of the relationships of these parameters to the condition of the vestibular aqueduct in 27 temporal bones with idiopathic endolymphatic hydrops from individuals with Meniere's disease. The results were compared with those from the same parameters in 79 control temporal bones without endolymphatic hydrops from individuals who had no premortem history of otologic disease. Pneumatization of the temporal bones of patients with Meniere's disease was in most cases less than that of control temporal bones; this difference was statistically significant. Poor pneumatization of the temporal bones of individuals with Meniere's disease appeared to be closely associated with hypoplasia of the vestibular aqueduct, an anatomical feature of many individuals with Meniere's disease. However, no statistically significant difference could be found between the thickness of the petrous bone in the periaqueductal region in bones of patients with Meniere's disease and this parameter in control bones.
Article
Meniere's disease (idiopathic endolymphatic hydrops) was studied in human temporal bone histology sections. Measurements were made of the area, length, width, angle, position, and external aperture of the vestibular aqueduct in 27 temporal bones of individuals with this disease. These measurements were compared with measurements of the same parameters in 88 normal temporal bones. It was found that small vestibular aqueducts were more often observed in the temporal bones of patients with Meniere's disease than in temporal bones from individuals without this disorder. The difference in size of the vestibular aqueduct in bones with hydrops and normal bones was statistically significant.
Article
Multidirectional and computerized tomography have been used for the radiographic assessment of the vestibular aqueduct in Meniere's disease. The results of studies performed by us and/or other authors indicate that there is a statistically significant difference in the size of the vestibular aqueduct between the Meniere's and control groups (in Meniere's disease the vestibular aqueduct is often narrowed or obliterated); and that periaqueductal pneumatization is often decreased or absent in ears affected by Meniere's disease. Recent histological studies performed on temporal bones of patients with Meniere's disease have confirmed these radiographic observations.
Article
The purpose of this study was to investigate the anatomy of the vestibular aqueduct (VA) and rugose portion (RP) of the endolymphatic sac. Serial horizontal sections of 79 normal temporal bones of individuals aged 20 to 102 years were used. Medial view graphic reconstruction of the VA was performed for each specimen to determine the area, length, angle and position of the VA. The relationship between the width of the VA and the area of the VA, and the relationship between the degree of development of the VA and the degree of development of the temporal bone (periaqueductal pneumatization and the otic capsule in the periaqueductal region) were also investigated. Measurements of the RP were also made and further histological study of the RP was performed on 30 selected specimens. We found that 1) the VA in adult temporal bone varies in size and can be classified as hypoplastic, normoplastic, or hyperplastic; 2) many of the VAs in each group have similar sizes, although they vary in length, angle, or position; 3) all or most of the RP was located within the VA in all but one specimen, which had a hypoplastic VA (in this specimen more than half of the entire RP extended into the posterior cranial fossa); 4) the histology of the RP was characteristic in each type of VA; and 5) the degree of development of the VA seems to correlate with the degree of development of the otic capsule in the periaqueductal region.
Article
Perilymph hypertension has been shown to produce hearing loss in animal experiments and in at least two clinical situations: chronic cerebrospinal fluid (CSF) elevation and oval window “gushers.” Idiopathic perilymph hypertension may be a factor in other otologic conditions as well. The indirect measurement of increased cochlear pressure is discussed and a plea made for otolaryngologists and audiologists to consider such measurements in inner ear disease of obscure etiology in order to validate the concept that increased cochlear pressure is associated with ear disease other than Ménière's.
Article
Intracranial pressure is transmitted to the perilymph of the cochlea via the cochlear aquaeduct and via Reissner's membrane to the endolymph. The "Tympanic Membrane Displacement Analyser (TDA)" is a new device that may be a useful non-invasive method to show intracranial and intracochlear pressure changes indirectly measured by tympanic membrane displacement during stapedial reflex contraction. The TDA was utilised in 20 normal persons and in 29 patients with unilateral diseases of the inner ear. No significant differences in the tympanic membrane displacement were found between patients with sensorineural hearing loss, patients with Ménière's disease, and normal persons.
Article
The tympanic membrane displacement technique (TMD) is aimed at evaluating intracochlear and intracranial pressure changes non-invasively. Therefore, the present paper describes the findings in patients with Ménière's disease where an increase in volume of the endolymphatic spaces is discussed. It should be investigated to which extent a change in the intracochlear pressure corresponds to different stages of the disease. It could be described that the intracochlear pressure does change over a certain period of persisting Ménière's, but that there is no extensive increase in intracochlear pressure between the attacks. The glycerol test as well as the acute attack (case report on one patient) are, however, characterised by distinct patterns. The same holds true for the late-stage Ménière's. It could be demonstrated that the functional patency of the cochlear aquaeduct in patients with long-term Ménière's history is reduced. This finding is surprising and should be investigated further. In essence, the TMD technique enables to better characterise Ménière patients, but it should not be a tool of routine diagnosis of the disease. In some audiological patients, it can also be beneficially applied (10).
Article
The present study summarizes the experimental findings obtained on the pressure in the inner ear fluids and on the effects of pressure changes on cochlear function in the guinea pig. Two types of pressures have to be distinguished in the inner ear fluid compartments: (i) hydrostatic fluid pressure and (ii) superimposed hydrodynamic high frequency (> 100 Hz) sound pressure oscillations. Hydrostatic pressure in the inner ear fluids in guinea pigs is in the order of 200 Pa (2 cm H2O) and shows slow (< 5 Hz) respiratory and pulsatory oscillations as well as considerable physiological variations in the range of -100 to +700 Pa. In normal ears, hydrostatic pressure in the perilymph equals pressure in the endolymph, and pressure changes applied to one compartment are immediately transmitted to the other one. A high compliance of Reissner's membrane seems to be the cause of this endolymphatic-perilymphatic pressure equalization. In experimental endolymphatic hydrops, a unique animal model for Meniere's disease, endolymphatic pressure is higher (100 Pa and above) than perilymphatic pressure. These pressure gradients occur only in late stages of hydrops, probably when Reissner's membrane has lost its high compliance after long standing distension. Positive endolymphatic-perilymphatic pressure gradients are secondary to and not the primary cause of hydrops formation. Changes of hydrostatic pressure do not affect auditory function as long as they stay in the physiological range. This includes the sudden loss of positive inner ear pressure that occurs in perilymph fistulas. The rationale for surgical repair of perilymph fistulas in patients in order to restore the hearing function thus becomes questionable. Other aspects of surgical repair, however, as e.g. prevention of labyrinthitis due to permanently open fistula, could not be investigated in this model, because in guinea pigs even large fistulas heal spontaneously within a few days. In experimental endolymphatic hydrops, deterioration of auditory thresholds was partially correlated to the presence of positive endolymphatic-perilymphatic pressure gradients. A change in pressure, however, occurred later than the first deterioration in auditory function. Therefore positive endo-perilymphatic pressure gradients may contribute to, but are not the only cause of hearing impairment.
Article
The external aperture width of the vestibular aqueduct was measured in living subjects of various ages, with normal and diseased ears. Measurements were made from 3-dimensional reconstruction of CT images, and the developmental process was studied. The following results were obtained. i) In Menière's disease the external aperture was hypoplastic and its width significantly smaller than that in normal individuals and those with chronic otitis media, including children. ii) There were no significant differences between normal ears and ears with chronic otitis media in either adults or children. The development of external aperture was completed in childhood. iii) In Menière's disease, hypoplasia evidently begins before childhood, which suggests that congenital factors are involved in the pathology of this disease.
Article
Variations in the size and shape of the human vestibular aqueduct were evaluated in 118 plastic casts of unselected specimens of human temporal bones. They were examined by conventional radiography and by high resolution CT. The degree of the mastoid and perilabyrinthine pneumatization was defined and classified into 3 types. The dimensions of the peripheral portion of the aqueduct were found to be related to the extent of the perilabyrinthine pneumatization.
Article
The MMS-10 Tympanic Displacement Analyser in a new device to measure the perilymphatic pressure in humans. This instrument was used in 25 patients with Menière's disease (28 affected ears) and a group of 50 young normal hearing subjects. No significant differences were found in perilymphatic pressure measurements between the groups. Although measurement parameters showed large inter-individual variation, the intra-individual correlation was good. In patients with Menière's disease, no relationship was found between perilymphatic pressure, hearing threshold, blood pressure, gender or age.
Article
Lateral polytomography of the vestibular aqueduct by computed radiography was carried out in 30 normal subjects and 25 patients with Meniere's disease, 14 of whom had bilateral involvement. The vestibular aqueduct could be identified clearly not only in normal subjects but also in patients with Menière's disease. Normal vestibular aqueducts were funnel-shaped or tubular, and the width of the external aperture was 6.0 mm on average. In contrast, a hypoplastic vestibular aqueduct with a narrow external aperture was often observed in patients with Menière's disease. Especially, in affected ears of patients with unilateral Menière's disease, the external aperture was very narrow; its mean width was 2.2 mm. In these cases, the most common radiographic configuration of the vestibular aqueduct was filiform. Meanwhile bilateral Menière's disease had a relatively wide external aperture compared with that of unilateral Menière's disease, although a hypoplastic vestibular aqueduct was also observed in patients with bilateral Menière's disease. As to the distribution of radiographic configuration types, bilateral Menière's disease had almost the same distribution as in normal ears. From these results, it was concluded that a hypoplastic development of the vestibular aqueduct was based on the etiology of Menière's disease, but general factors as well as a hypoplastic vestibular aqueduct seem to be responsible for bilateral involvement.
Article
A high jugular bulb (JB) is thought to affect structures of the inner ear and possibly cause symptoms there, but clear histological findings of an anatomical relationship between a high JB and the inner ear have not yet been described. We surveyed horizontal sections of 1,591 temporal bones from the collection of the Otopathology Laboratory at the University of Minnesota in Minneapolis, Minnesota, defining a high JB as a JB extending above the inferior margin of the basal cochlear turn. In 65 specimens (16%), we found a high JB with its vascular wall obviously thinner than that of a low JB. Bony resorption was occasionally observed around high JBs. Sixteen specimens showed a bony deshiscence between the JB and the endolymphatic sac. Clinical charts showed no obvious symptoms associated with a high JB. Our findings suggest that the JB may have potential to expand upward postnatally. Although our study confirmed occasional bony dehiscence between the JB and the endolymphatic sac, JBs with this involvement may have only a minor effect on function in the inner ear.
Introduction to acoustic imped-ance
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Analysis of some auditory characteristics In: Handbook of Mechanical Psychology
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Dimensional anatomy of the vestibular aqueduct and the endolymphatic sac (rugous portion) in human temporal bones
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