Observation of the external aperture of the vestibular aqueduct using three-dimensional surface reconstruction imaging

Observation of the external aperture of the vestibular aqueduct was hitherto possible only in cadavers or dry temporal bones; 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.     

Investigation of the external aperture of the vestibular aqueduct in Menière's disease by three-dimensional image analysis.

The width of the external aperture of the vestibular aqueduct was measured in patients with Meniere's disease using three-dimensional images. The width of the aperture on the affected side was significantly smaller compared with that in normal ears or ears with chronic otitis media. Also, the width of the aperture on the opposite (healthy) side in unilateral Meniere's disease was significantly smaller than in these two other groups. These findings suggest that the aqueduct is incompletely developed in patients with Meniere's disease and that this may be related to the pathogenesis of this condition. Also, in unilateral Meniere's disease the opposite ear runs a high risk of eventually developing the disease.     

梅尼埃病听力损失程度和类型对短声诱发的SP/AP比值的影响

目的 :探讨耳蜗电图 (ECoch G)在梅尼埃病诊断中听力损失程度和类型 ,对交替短声诱发的负性总和电位 (SP)与动作电位 (AP)比值 (SP/ AP)的影响。方法 :采用鼓膜电极耳蜗电图描记术 ,对梅尼埃病 90耳 (梅尼埃病组 )和其他原因感音神经性聋 6 0耳 (感音神经性聋组 )及正常听力 5 0耳 (正常对照组 )记录了 AP和 SP各参数 ,对结果进行对照分析。结果 :AP潜伏期 3组差异无显著性 ,AP振幅正常对照组高于梅尼埃病组和感音神经性聋组 (P <0 .0 5 ) ,SP振幅正常对照组高于感音神经性聋组 (P <0 .0 1)而低于梅尼埃病组 (P <0 .0 1)。SP/ AP振幅比值梅尼埃病组 (48.0 9± 14 .38) % ,明显高于感音神经性聋组 (2 0 .0 2± 15 .0 0 ) %和正常对照组 (2 3.85±8.0 5 ) % ,(均 P <0 .0 1)。梅尼埃病组 SP/ AP比值与主观纯音听阈呈正相关 (r =0 .5 6 0 1,P <0 .0 1) ,其异常率为 73%。梅尼埃病不同听力损失组中 ,SP/ AP比值轻度耳聋组低于中度和中重度组 (均 P <0 .0 1) ,后两组差异无显著性意义 (P >0 .0 5 )。低频型低于平坦型 (P <0 .0 5 ) ,高频型和前两型相比差异无显著性意义。结论 :SP/ AP振幅比值异常增大有助于梅尼埃病的临床诊断 ,在一定范围内随听阈提高而增大 ,必须有足够的残余听力才能记录质量好的图形。     

Electrocochleography in the diagnosis of Meniere's disease

This study prospectively analyses electrocochleography (ECoG) recordings obtained from ears demonstrating symptoms highly suggestive of Meniere's disease. Comparison is made with ECoG recording from ears in which the diagnosis of Meniere's is considered unlikely (control ears). Electrocochleograph recordings were made through a transtympanic recording needle, situated in the round window niche. Analysis was made of the 1 kHz tone burst summation potential (SP) and the summation potential:action potential (SP/AP) ratio response to a 90 dB click. All patients were prospectively awarded a Meniere's score based on a 10-point scale, and comparison was made between ears awarded a score of 7 or greater (Meniere's ears; n > 500), and ears awarded a score 3 or less (control ears; n > 900). Results demonstrate a significant difference in the 1 kHz SP response, and the SP/AP ratio, between "control" and "Meniere's" ears. Furthermore, we show that SP negativity is proportional to the amplitude of the AP click response, and in patients producing an AP click amplitude exceeding 10 V, sensitivity of the tone burst test approaches 85%. This study provides further evidence suggesting the useful role of electrocochleography in determining a diagnosis of endolymphatic hydrops. and demonstrates improved sensitivity of the 1 kHz SP response, compared with SP/AP click ratio, in the diagnosis of Meniere's disease.     

Tomography of the vestibular aqueduct in ear disease.

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.     

Extratympanic electrocochleography: diagnostic and predictive value

OBJECTIVE: To define the clinical value of extratympanic electrocochleography (ECoG) in the diagnosis of Meniere's disease. STUDY DESIGN: Retrospective case review. SETTING: An otology/neurotology referral center. PATIENTS: A group of 252 patients with symptoms consistent with Meniere's disease and 20 normal-hearing control subjects. INTERVENTION: All patients underwent audiologic testing and extratympanic ECoG at the time of initial evaluation and, when possible, following treatment. MAIN OUTCOME MEASURES: Audiologic thresholds and summating and action potential ratios (SP:AP). RESULTS: Patients were classified into definite, probable, possible, and bilateral Meniere's disease groups according to American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guidelines. The definite Meniere's group demonstrated an elevated SP:AP ratio in 74% of cases, the possible Meniere's group in 64%, and the bilateral group demonstrated elevated ratios in both ears in 66%. Contralateral ears produced elevated ratios in 42% for unilateral cases, whereas 40% of these ears reported at least one contralateral symptom. All 40 control ears were normal (SP:AP > or = 0.50). Results statistically correlated (p = 0.004) with the Meniere's staging system set forth in the 1995 AAO-HNS guidelines. No correlation was found between ECoG results and disease duration. Although 72% of the 86 follow-up patients reported complete or substantial vertigo control, changes from initial ECoG results did not specifically correlate to vertigo, tinnitus, or aural fullness improvement. CONCLUSIONS: Extratympanic ECoG can be useful in the diagnosis of Meniere's disease, lending promise to possible cases where objective audiologic data are lacking. Each testing center should study its own results to establish meaningful parameters and confidence levels.     

Clinical analysis of 95 patients with large vestibular aqueduct syndrome]

OBJECTIVE: To investigate the occurrence, genetic inheritance, and hearing loss conditions of large vestibular aqueduct syndrome (LVAS), and to measure the width of external aperture of vestibular aqueduct (VA) of LVAS, and to analyze the relationship between the hearing loss and the width of external aperture. METHODS: A retrospective review was conducted by the history, auditory, and vestibular function examinations in 95 patients (190 ears) of LVAS. The width of VA was measured by CT scanning criterion of each LVAS patients in the past 10 years (from 1992 to 2002). RESULTS: In 95 patients, there were male 65 cases and female 30 cases. The male cases was more than the females by a ratio of 2.2:1. Twelve cases (12.6%) would have familial genetic history. The average of the consult age was 7.6 years (range from 1.2 to 39 years). The most patients were misdiagnosed, the hearing deterioration originated from mild head trauma in 21 cases (22.1%), the hearing loss after common cold in 13 cases (13.6%). Nine cases (9.5%) misdiagnosed as sudden hearing loss, 5 cases (5.3%) as ototoxic hearing loss of Aminoglycoside antibiotic. The profound hearing loss was found in 172 ears (92.4%). The average width of external aperture of LVAS was 7.5 mm +/- 1.2 mm (mean +/- s, 77 cases, 154 ears). The level of hearing loss did not proportional to the width of VA. The hearing impairment could be derived from protein-rich endolymph refluxed into the cochlear and vestibule. CONCLUSION: The LVAS is distinct clinical entity characterized by fluctuate and progressive SNHL. The diagnosis depends upon the CT scan and MR image. If the hearing fluctuated and subsequently improved, the children were kept under conservation treatment. If the significantly decreased of hearing effected school performance, the cochlear implant might be considered.     

利用螺旋CT三维图像对梅尼埃病患者前庭小管外口的研究

目的 通过螺旋CT三维重建技术观察梅尼埃病患者前庭小管外口，研究其宽度的大小与该病发生的内在联系。方法 分别观察比较梅尼埃病患者和正常受试者。对颞骨岩部范围进行容积扫描，采用后颅窝内面观、表面法进行三维重建。在三维方向上旋转切割后图像，直接测量前庭小管外口最大直径。结果 所有受试者三维图像上前庭小管外口均显示清晰，梅尼埃病患者前庭小管外口宽度与正常耳组间的差异具有非常显著性意义。单侧梅尼埃病患者病耳与非病耳前庭小管外口宽度的差异无显著性意义。结论 前庭小管发育不良为梅尼埃病的病理解剖学基础，并且常常累及双耳。     

Analysis of growth model in vestibular aqueduct during human fetal development]

OBJECTIVE: To characterize the growth of the developing vestibular aqueduct in order to gain a better understanding of the possible origins of enlarged vestibular aqueduct. METHODS: Serial sections from 32 temporal bones for every other week from human embryos ranging in age from 6 to 38 weeks were studied with 3DMed medical image analysis software. The internal, external aperture, midpoint diameter and length vestibular aqueduct were analyzed with regression analysis to obtain a growth curve. RESULTS: The internal aperture of vestibular aqueduct was began to form at 6 weeks' gestation. It grew to reach the posterior surface of the petrous bone in the posterior cranial fossa by 10 weeks' gestation. All width parameter mean value in our embryos nerve reached the maximum average width in the adult. Statistical analysis showed that the vestibular aqueduct grew in a nonlinear continuous fashion and instability trend throughout embryonic life, except length parameter. CONCLUSION: The vestibular aqueduct grows in a nonlinear fashion throughout embryonic life. The widest aqueduct measured in embryonic life does not reach the maximum average width in the adult. These results suggest that it would be possible for vestibular aqueduct to develop postnatally.     

A clinical study of electrocochleography in Menière's disease

Electrocochleography (ECochG) of 168 ears with definite Meniere's disease was studied. The results were compared with recordings from 29 normal ears and 444 ears with other types of sensorineural hearing loss. It is shown that the SP/AP ratio is much more useful than SP amplitude for detecting endolymphatic hydrops. There was little difference in the mean values of SP/AP from those proposed by many other investigators; the mean values all being near 0.25. From 0.30 to 0.40 of SP/AP was considered adequate as the upper limit. Following intravenous administration of glycerol, a significant decrease in SP/AP was found in 21 Meniere's ears. However, there was no change of SP/AP after oral administration of glycerol and isosorbide. This difference may be due to the fact that a larger oral than intravenous administration is necessary to affect SP/AP. Although a postoperative decrease of 10% or more in SP/AP was observed in 5 patients, 10 patients followed up for 2 years or more after surgery did not show a statistically significant change of SP/AP and pure tone threshold. ECochG should be repeatedly recorded to be useful as a monitor for the presence of hydrops. It is discussed whether biochemical or mechanical changes in endolymph may cause a decrease in SP/AP after the use of dehydrating agents and endolymphatic sac surgery.     

双侧大前庭导水管综合征7例报告

目的：探讨双耳均为大前庭导水管综合征病例的ＣＴ和听力改变特征。方法：对７例经高分辨率ＣＴ证实为双耳大前庭导水管综合征病例的导水管管径和听阈改变进行分析。结果：ＣＴ示扩大的前庭导水管的管径两耳不对称,管径较大侧耳的听力损失重,差异有显著性意义（Ｐ〈０．０５）。结论：测量前庭导水管的管径对估计听力损失的程度和预后有重要意义。     

Unilateral Meniere's disease: is the contralateral ear normal?

Certain investigations in patients with unilateral Meniere's disease may on occasion show abnormalities in the completely symptomless contralateral ear. These tests include transtympanic electrocochleography, the acetazolamide cochlear hydration test, vestibular aqueduct tomography, and caloric testing. Eventually these ears may well become symptomatic. Previous studies have shown that otoadmittance changes are a sensitive indicator of glycerol-induced intracochlear pressure alterations in hydropic ears, but do not occur in patients without Meniere's disease. Otoadmittance parameters were evaluated in the asymptomatic ears of 73 consecutive patients with unilateral Meniere's disease. Satisfactory traces and adequate dehydration were achieved in fifty-nine. A significant change in the maximum conductance, similar to that often seen in symptomatic hydropic ears, was found in twenty-four cases (40.7%). The presence of functional abnormalities in well over one-third of asymptomatic ears means that they cannot be used as controls in clinical research studies. Furthermore, recognition of contralateral latent hydrops at the initial otologic assessment may modify the subsequent treatment strategy.     

耳蜗电图在梅尼埃病诊断中的价值

迄今尚缺乏诊断梅尼埃病的敏感且特异的客观试验，７０年代以来，若干研究探讨了耳蜗电图（Ｅｌｅｃｔｒｏｃｏｃｈｌｅｏｇｒａｍ，ＥＣｏｃｈＧ）在梅尼埃病诊断中的价值，认为典型的改变是－ＳＰ异常增大，导致－ＳＰ／ＡＰ比值增高，以及－ＳＰ－ＡＰ复合波形异常增宽。各家报告－ＳＰ／ＡＰ诊断梅尼埃病阳性率从３２％至８７％．本文报告了９７例１００耳梅尼埃病鼓室内法检测的耳蜗电图结果，４９例－ＳＰ／ＡＰ比值异常增高，阳性率４９％；波型异常增宽１７耳，总阳性率６６％．眼震电图检测的阳性率６１％．耳蜗电图和眼震电图改变一致的４３耳，二者总阳性率为８４％。对各家阳性率不一致的原因作了分析。认为耳蜗电图－ＳＰ／ＡＰ比值诊断梅尼埃病的敏感性不如文献报告的那么乐观，在目前尚无更敏感更特异的诊断手段的情况下，耳蜗电图和眼震电图在梅尼埃病的诊断中起着相互印证和相互补充的作用。     

疏波和密波短声诱发的动作电位潜伏期差对梅尼埃病的诊 …

OBJECTIVE: To study the value of condensation and rarefaction clicks evoked action potential (AP) latency difference (LD) in diagnosis of Meniere's disease. METHODS: AP was recorded with ECochG in controls (50 ears) and patients with Meniere's disease(90 ears) and sensorineural hearing loss(SNHL) of other origins(60 ears). LD was calculated and analyzed. RESULTS: LD in patients with Meniere's disease was (0.30 +/- 0.15) ms, which was significantly larger than that of controls(0.18 +/- 0.07) ms and of patients with SNHL of other origins(0.20 +/- 0.10) ms (P < 0.01). In the group of Meniere's disease, LD in patients with the mild and moderate hearing impairment was larger than those with severe hearing loss(P < 0.01) and LD in patients with low tone or high tone auditory sensation curve was larger than those with flat auditory sensation curve(P < 0.01). Positive rate was 4/60(6.7%) in other SNHL patients and 58/90(64.0%) in Meniere's disease group respectively. CONCLUSION: The increase in condensation and rarefaction click evoked AP latency difference can be an objective parameter in diagnosis of Meniere's disease.     

Significance of tomography in Meniere's disease: visualization and morphology of the vestibular aqueduct

The revival of endolymphatic sac surgery has led to many investigations in Meniere's disease, including lateral tomography of the vestibular aqueduct. Contrary to recent literature, we found no difference in the presence and morphology of the vestibular aqueduct when assessed radiologically in a group of Meniere's patients and a control group. Our assessment of this information in regard to etiology and treatment of Meniere's disease is presented.     

Three-dimensional analysis of 61 human endolymphatic ducts and sacs in ears with and without Menière's disease

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.     

前庭诱发肌源性电位结合纯音测听在大前庭水管综合征患者的临床应用

目的 通过记录、分析大前庭水管综合征（LVAS）患者的前庭诱发的肌源性电位(VEMP) 和纯音测听（PTA）状况,了解其球囊及前庭下神经功能和纯音听力特征,探讨其在LVAS患者的临床应用及意义。方法 对22例（42耳）LVAS患者行内耳高分辨率CT扫描、纯音测听和VEMP检查,对检查结果结合其临床症状进行总结、分析。结果 双侧短声刺激42患耳中25耳（占59.5%）VEMP表现为高振幅和（或）低阈值;42患耳纯音测听有30耳（占71.4%）表现为低中频（2KHz以下）存在明显气骨导差的混合性聋。VEMP低阈值组,前庭水管内径平均值为（4.30±0.53）mm,纯音听力低中频平均气骨导差值为（36±17）dB HL, 19耳主观听力易受外界原因或发热致颅内压改变而波动;VEMP非低阈值组前庭水管内径平均值为（2.80±0.67）mm,纯音听力低中频平均气骨导差值为（32±15）dB HL,4耳主观听力易受外界原因或发热致颅内压改变而波动。结论 VEMP阈值较低者,其前庭水管平均内径值较大,主观听力也易受外界原因或发热致颅内压增高的改变而波动。而纯音听力损失程度与前庭水管内径平均值无相关性,与VEMP振幅的大小及阈值的高低亦无相关性。     

Electrocochleography in patients with Meniere's disease

OBJECTIVE: The objective of this study was to evaluate the role of electrocochleography (ECoG) in the diagnosis of Meniere's disease. STUDY DESIGN: This study is a retrospective case review. METHODS: Patients undergoing ECoG for Meniere's disease between 1995 and 2003 were identified and segregated as having definite , probable , or possible Meniere's disease according to the 1995 American Academy of Otolaryngology-Head and Neck Surgery guidelines for Meniere's disease classification. Those determined to have probable and possible Meniere's disease were then combined to form a less-than-definite group for statistical analysis. Electrocochleography summating potential (SP)/action potential (AP) ratios were determined, and ratios greater than 0.4 were considered abnormal. The 2 groups were then compared to assess for any correlation between ECoG with the 1995 American Academy of Otolaryngology-Head and Neck Surgery Meniere's disease classification. RESULTS: Sixty patients with definite Meniere's disease and 37 with less-than-definite Meniere's disease were identified. Overall, 59.8% had abnormally elevated SP/AP ratios. Of those with definite Meniere's disease, 66.7% had abnormally elevated SP/AP ratios, whereas of those with less-than-definite Meniere's disease, 52.7% had abnormal ECoGs ( P = .069). CONCLUSIONS: A significant difference in ECoG results was not seen between the definite and less-than-definite Meniere's disease groups. Furthermore, approximately 30% of those with definite Meniere's disease would not be classified as having Meniere's disease based on ECoG results. Because of its lack of sensitivity, ECoG should not play a decisive role in determining the presence or absence of Meniere's disease.     

Major and minor temporal bone abnormalities in children with and without congenital sensorineural hearing loss

OBJECTIVE: To determine the extent of correlation between sensorineural hearing loss (SNHL) and abnormal temporal bone anatomy in children. DESIGN: Axial and coronal high-resolution computed tomographic scans of the temporal bones of 247 children (494 ears) aged 2 months to 15 years with and without SNHL were blindly reviewed. The presence or absence of mild or severe cochlear dysplasias, vestibular dysplasias, and an enlarged vestibular aqueduct (VA) were recorded. The width of the VA was measured. The height, width, and length of the internal auditory canal (IAC) were measured, and abnormalities were described as narrow, widened, or bulbous. Clinical information was then reviewed to determine the presence or absence of a congenital syndrome and/or SNHL, and historical factors that might be responsible for SNHL. MAIN OUTCOME MEASURE: The relationship between radiographic findings and SNHL. RESULTS: One hundred thirteen patients (185 ears) had SNHL. Significant abnormal temporal bone anatomy in children with vs without SNHL included major cochlear and vestibular dysplasias (17% vs 0%; P<.001), enlarged VA (>2 mm) (5% vs 0%; P<.001), and narrow IAC (< or =2 mm) (4% vs 1%; P=.03). The average IAC width (4.85 vs 5.02 mm), height (4.39 vs 4.62 mm), and length (11.22 vs 11.44 mm) were not statistically different between children with vs without SNHL. In children with vs without SNHL, neither a widened (0.5% vs 3.6%) nor a bulbous (9% vs 8%) IAC was seen more often in children with SNHL. In ears with SNHL, the presence of a congenital syndrome significantly increased the risk of cochlear and vestibular abnormalities of the temporal bone (45% vs 14%; P<.001), including IAC abnormalities (30% vs 2%;P<.001), which overall were more commonly seen in children with (20%) vs without (3%) a congenital syndrome regardless of the presence of SNHL. No children with an enlarged VA had a congenital syndrome. CONCLUSIONS: Well-established temporal bone abnormalities such as cochlear and vestibular abnormalities and a grossly enlarged vestibular aqueduct are significantly found in children with SNHL. A narrow IAC is found more often in children with vs without SNHL. No significant correlation is found between SNHL and radiographic findings of a widened or bulbous IAC. In children with a congenital syndrome, more IAC abnormalities were seen, regardless of the presence of SNHL. In children with SNHL, the presence of a congenital syndrome increases the likelihood of a cochlear or vestibular abnormality.     

大前庭水管综合征与波动性听力损失

目的 分析波动性听力损失在大前庭水管综合征（large vestibular aqueduct syndrome,LVAS）中的特征。方法 总结LVAS13例（23耳）的临床资料，对其波动性听力损失的机理、LVAS诊断及治疗作一讨论。结果 LVAS13例（23耳）中双侧10例，单侧3例，平均年龄7.9岁。多幼年起病，呈缓慢进行性听力减退，波动性突然加重12耳，并伴发作性眩晕3例。6例有提重物、运动、乘飞机、感冒史。3例有遗传性家庭史。纯音听力多呈高频下降型感音神经性聋。眼震电图12耳6耳一侧半规管麻痹。高分辨率CT显示大前庭水管扩大2.5-8mm，有的深达前庭总脚。结论 LAVS多于幼年时出现缓慢进行性听力减退，可伴波动性突发性听力下降、眩晕，常与增加颅内压的活动有关，故应注意预防和避免。