Tympanometric findings in patients with enlarged vestibular aqueducts

OBJECTIVES: The purpose of this study was to study systematically some relationships between the resonance frequency of the middle-ear transmission system and the volume of the endolymphatic duct and sac in patients with an enlarged vestibular aqueduct (EVA). STUDY DESIGN: Prospective study. METHODS: Thirteen patients (24 ears) with EVA, 17 subjects (29 ears) with normal hearing, and 17 patients (21 ears) with sensorineural hearing loss without EVA served as experimental subjects. Standard pure-tone audiometry, standard clinical tympanometry (using a 226-Hz probe tone), and multifrequency tympanometry were performed on each ear. Magnetic resonance imaging was used to determine the area of the cochlear modiolus and the volume of the endolymphatic duct and sac. RESULTS: The audiometric configurations for most patients sloped downward from the low to the high frequencies. A significant air-bone gap was computed at each of these test frequencies. Multifrequency tympanometry yielded resonance frequencies for the patients with EVA that was significantly lower than those measured for the control subjects. In general, for patients with EVA, the resonance frequency of the middle ear system decreased as the volume of the endolymphatic duct and sac increased. This inverse relation was significant (correlation coefficient = -0.483, P =.0157). However, there was no correlation between resonance frequency and the degree of cochlea modiolar deficiency. CONCLUSIONS: Clinically, our findings suggest that EVA probably should be included in the differential diagnosis for a patient who presents with a moderate to severe mixed hearing loss, a normal tympanogram at 226 Hz, and a resonance frequency that is abnormally low.     

Non-syndromic bilateral enlarged vestibular aqueducts in two siblings

Enlarged vestibular aqueduct is one of the most frequent inner ear malformations with early manifested sensorineural hearing loss. It is often associated with Pendred syndrome. The non-syndromic familial enlarged vestibular aqueduct entity is less described with only a few cases reported in the literature. It is thought to be a varying presentation on the phenotypic spectrum of genetic mutation in the same locus of chromosome 7q31. The familial inheritance has been suspected to be autosomal recessive. In this case report, we present a patient who presented to the clinic with hearing loss after blunt head trauma with a soccer ball. Suspected enlarged vestibular aqueduct was confirmed to be bilateral on CT scan of the temporal bones. Additional inquiry into the family history revealed that her sister also had bilateral sensorineural hearing loss at an early age. Unpredictably, bilateral enlarged vestibular aqueducts were confirmed in the sister with similar imaging modality. The clinical presentation, diagnosis, and treatment strategies are reviewed along with the current literature.     

单纯前庭导水管扩大行人工耳蜗植入患儿临床特征回顾性研究

目的　回顾性研究已行人工耳蜗植入的单纯前庭导水管扩大患者临床资料,研究其发病与植入年龄分布情况、手术并发症、发病诱因,为临床前庭导水管扩大诊疗提供依据。方法　回顾性研究2000年1月～2015年4月345例经颞骨CT诊断为单纯前庭导水管扩大并于北京同仁医院行人工耳蜗植入患儿临床资料,包括发病诱因、发病年龄、语前/语后聋情况、植入前听力水平及助听器使用情况、手术并发症,分析不同年龄段的发病特点、人工耳蜗植入情况、病程与佩戴助听器的关系,并对不同发病诱因进行分类总结。结果　单纯前庭导水管扩大患者发病年龄的中位数为1（0,2）岁,植入年龄的中位数为3.75（2.17,12）岁。大部分病例（276/345例）无明显诱因,有明确家族史者27例 （7.9%）,外伤所致听力下降者14例（4.1%）,感冒后诱发者10例（2.9%）,使用耳毒性药物所致者13例（3.8%）,有麻疹病毒感染史2例（0.6%）,1例为早产儿胆红素脑病所致。术中“井喷”发生率21.16%,无其他并发症。随病程延长佩戴助听器者比例增加,且两者之间具有显著相关性。结论  单纯前庭导水管扩大患者的发病年龄1岁左右,植入年龄3～4岁,病程越长术前曾使用助听器比例越高。此类患者大部分为不明原因听力下降,此外尚有部分是外伤、感冒或使用耳毒性药物所致,所以诊断为前庭导水管扩大的患者要积极避免以上诱因。前庭导水管扩大发病后要及时诊治,听力下降即考虑佩戴助听器,助听器不能补偿时需积极行人工耳蜗植入。     

A case of bilateral enlarged vestibular aqueducts and unilateral hearing loss at birth

Screening of newborn hearing is nowadays widespread, and as many as 3.4% of all screened infants are found to have unilateral hearing loss. However, we, as clinicians and parents, usually dismiss the severity of unilateral hearing loss in pediatric patients. Recently, we experienced the case of unilateral hearing loss since birth in a 2-year-old girl who was finally found to have bilateral enlarged vestibular aqueducts when the disorder progressed to bilateral hearing loss. Proper evaluation of the cause of hearing loss, including imaging studies of the inner ear, and consecutive hearing evaluations should be mandatory in children with unilateral sensorineural hearing loss, due to the possibility of progression of hearing loss bilaterally.     

Cochlear implantation in patients with enlarged vestibular aqueduct. A case series with literature review

Objectives: To report our institutional experience of the management of patients with enlarged vestibular aqueduct (EVA) and compare it to the literature.

Methods: We carried out a retrospective review of patients’ records from 1993 to 2015. The age, sex, associated malformations, relevant past medical history, genetic screening results, possible surgical incident, implant model and duration of follow- up, outcome in terms of Categories of Auditory Performance (CAP scores), and integration or resuming mainstream school or work were recorded.

Results: We had 11 patients (six boys and five girls) with EVA who underwent cochlear implant surgery in our center during the 22-year study period, out of a total of 827 implanted (1.3%). The mean age at surgery was 8.9 years ranging from 0.6 to 35 years. EVA was bilateral in 10 cases, isolated anatomical finding in seven cases, and associated with other malformations in four. Cochlear implantation was bilateral in five cases and unilateral in six. The mean follow- up duration was 48.3 months (range: 3–120). No postoperative complication was observed and all the patients could regain a serviceable hearing, attending normal school and working normally.

Conclusion: EVA is frequently observed in the deaf population without an identifiable cause. The hearing loss is usually progressive and may result in cochlear implantation which has proved its efficiency in rehabilitating EVA patients.     

前庭导水管扩大患者SLC26A4单等位基因突变研究

 前庭导水管扩大（enlarged vestibular aqueduct, EVA）多为常染色体隐性遗传。研究表明SLC26A4基因突变是导致EVA的主要致病因素,有的EVA患者即使进行SLC26A4基因测序也未能发现双等位基因突变,对于只携带一个突变位点的患者该如何解析呢？为明确SLC26A4单等位基因突变EVA的致病因素,国内外学者开展了大量研究,提示EVA是一种复杂的疾病,涉及SLC26A4、FOXI1和KCNJ10等多个遗传基因。此外,还有可能与环境因素共同致病。本文就EVA患者SLC26A4单等位基因突变的研究进展进行综述。     

前庭水管扩大患儿纯音听力特征性表现——低频骨气导差

目的：分析前庭水管扩大（EVA）患儿行纯音测听检查时出现低频骨气导差的比例,探讨纯音测听检查辅助临床诊断EVA的意义。方法：所有患儿均经小儿行为测听或纯音测听、声导抗检查,并行颞骨CT扫描或耳蜗磁共振水成像检查了解中耳及内耳的发育情况。结果：声导抗检查：78例（154耳）中耳鼓室声导抗曲线均为A型,其中单纯A型126耳,As型25耳,Ad型3耳;15耳引出声反射。纯音测听检查：在250Hz处,126耳（81．8oA）存在骨气导差,按听力损失程度分类：轻度1耳,中度12耳,中重度18耳,重度38耳,极重度57耳;在500Hz处,102耳（66．2％）存在骨气导差,按听力损失程度分类：轻度0耳,中度9耳,中重度17耳．重度35耳,极重度41耳。结论：进行纯音测听检查时,在中耳功能正常（中耳声导抗鼓室图为A型）情况下,若发现明显的低频骨气导差,可有66．2％～81．8％的概率提示患儿存在EVA。     

Long-term follow-up of hearing loss in children and young adults with enlarged vestibular aqueducts: relationship to radiologic findings and Pendred syndrome diagnosis

OBJECTIVE: To describe the long-term audiologic findings in pediatric patients with enlarged vestibular aqueducts (EVAs). The relationship between the hearing loss (HL) and the dimensions of the EVA, enlarged endolymphatic duct (EED), or enlarged endolymphatic sac (EES) was also investigated. The influence of a Pendred syndrome (PS) diagnosis on the audiologic phenotype was also examined. STUDY DESIGN: Retrospective analysis of case notes and imaging records, including measurement of the dimensions of the EVA, EED, and EES. SETTING: Tertiary referral center. PATIENTS: Twenty-seven patients (21 female, 6 male) had an EVA in at least one ear. Eighty-five percent had bilateral enlargements. Median age at onset of follow-up was 5.0 years, and median follow-up was 9.7 years. MAIN OUTCOME MEASURES: Hearing thresholds at the start and end of follow-up, rate of progression of HL, history of sudden drops in hearing. RESULTS:: All ears with an EVA had HL. Average HL at the start and end of follow-up was severe. Thirty-seven percent of patients had progressive HL, and 33% reported sudden drops in hearing. Progression was significantly associated with a history of sudden drops. PS patients had worse hearing at the end of follow-up as compared with nonsyndromic patients. There was no evidence of a relationship between the dimensions of the EVA, EED, or EES and the severity or progression of HL. CONCLUSIONS: Patients with EVAs should be advised to avoid known trigger factors for sudden drops in hearing (e.g., minor head trauma). A diagnosis of PS may be associated with a worse audiologic prognosis.     

CT多平面重组在大前庭水管综合征诊断中的应用

目的探讨CT多平面重组（mulitiplanar reformation，MPR）在大前庭水管综合征诊断中的应用价值。方法选取31例前庭水管扩大患者轴位扫描原始图像、利用原始图像获取对称性轴位MPR图像及前庭水管最大显示MPR图像，比较三种图像中前庭水管的显示情况。结果轴位扫描图像显示前庭水管左右对称3例（9．68％），两种经MPR处理后图像均显示前庭水管左右对称；原始扫描图像前庭水管长肢全程显示24例，未全程显示不能进行前庭水管经线测量7例；30例患者前庭水管最大显示MPR图像上可全程显示前庭水管长肢并进行测量。结论前庭水管最大显示MPR图像能对称显示双侧前庭水管全程显示前庭水管长肢，对前庭水管扩大的准确测量具有重要意义。     

SLC26A4 p.Thr410Met homozygous mutation in a patient with a cystic cochlea and an enlarged vestibular aqueduct showing characteristic features of incomplete partition type I and II

Mutations of SLC26A4 are associated with incomplete partition type II (IP-II) and isolated enlargement of the vestibular aqueduct (EVA). We experienced a congenitally deaf 6-year-old boy with a rare p.Thr410Met homozygous mutation in SLC26A4 who underwent bilateral cochlear implantation. He had bilateral inner ear malformation, in which the dilated vestibule and EVA were identical to those in IP-II, but the cochlea lacking a bony modiolus resembled that in incomplete partition type I. These results suggest that homozygous mutations in SLC26A4 are always associated with EVA, while the severity of cochlear malformation may vary depending on the type of SLC26A4 mutation.     

Common clinical features of children with enlarged vestibular aqueduct and Mondini dysplasia

OBJECTIVES/HYPOTHESIS: The purpose of the study was to investigate the etiological factors and the audiological data of different types of inner ear malformations, which the authors thought might be helpful in elucidating the inter-relation among malformations and shedding light on pathogenesis. STUDY DESIGN: Retrospective study from 1998 to 2002 at a tertiary care university hospital. METHODS: One hundred sixty consecutive children with a total of 302 affected ears undergoing high-resolution computed tomography of the temporal bone for sensorineural hearing loss were enrolled. The image results were correlated with causes and origins, hearing loss patterns, hearing levels, and audiogram configurations. RESULTS: Inner ear malformation was present in 114 (38%) ears. The most common malformations were enlarged vestibular aqueduct, incomplete partition of cochlea (Mondini dysplasia), large vestibule, and semicircular canal dysplasia, presenting either as isolated finding or in combination. Eighty-four (74%) ears had abnormalities confined to these four malformations; only 30 (26%) ears showed other malformations. Patients with complex of enlarged vestibular aqueduct, Mondini dysplasia, large vestibule, and semicircular canal dysplasia (EMVS complex) demonstrated a significantly higher incidence of fluctuating hearing loss (93%) and a better hearing level compared with those with other malformations. Homogeneity in audiological features among these four malformations was also disclosed. CONCLUSION: The authors identified a distinct clinical entity, the EMVS complex, which is characterized by fluctuating hearing loss and a better hearing level. The authors proposed that malformations belonging to this complex result from a common pathogenetic mechanism.     

Delineating the hearing loss in children with enlarged vestibular aqueduct

Objective/Hypothesis: To explore the clinical characteristics and audiologic outcomes in children with enlarged vestibular aqueduct (EVA). Study Design: Retrospective study in a pediatric tertiary care facility. Methods: A total of 54 cases (82 ears) of children with EVA were identified with complete records, including otologic evaluation, imaging studies, and audiologic assessments. The diagnosis of EVA was confirmed by computerized tomography scan/magnetic resonance imaging of the temporal bone. Hearing status was assessed using behavioral testing or auditory brainstem response (ABR). Tympanometry, acoustic reflex, and vestibular evoked myogenic potential (VEMP) testing were also performed when appropriate. Results: Fifty‐two percent of our EVA cases showed bilateral involvement, and 43% of all ears with EVA also had cochlear malformations, such as Mondini dysplasia. Sensorineural HL was initially diagnosed in 16 ears (20% of the total) with EVA whereas conductive or mixed HL was found in 66 ears (80% of the total). Further review of all EVA cases with sensorineural HL showed lack of proper bone conduction testing, so air‐bone gaps were missed. Despite air‐bone gaps in EVA ears, middle ear pressure and mobility were usually normal, along with present acoustic reflexes. VEMP responses were present with abnormally low thresholds. Conclusions: Air‐bone gap(s) can be found in most ears with EVA if both air and bone conduction thresholds are properly tested. Normal tympanometry, presence of acoustic reflex and low threshold VEMP responses suggest that the air‐bone gap in EVA is due to an inner ear anomaly, similar to the “third” labyrinthine window syndrome.     

64排螺旋CT多平面重建和容积再现图像在面中部复杂骨折中的临床应用

目的：探讨64排螺旋CT多平面重建（MPR）及容积再现（VR）图像在面中部复杂骨折中的临床应用价值。方法：对46例面中部复杂骨折患者进行64排螺旋CT薄层扫描,容积数据传送到工作站进行MPR和VR三维成像。结果：46例面中部366处骨折,MPR图像对面中部各部位骨折的显示率为100％;VR图像对颧骨、颧弓、下颌骨骨折的显示率为100％,对上颌骨骨折的显示率为94．3％、眼眶骨折为93．2％、筛骨骨折为13．0％、蝶骨骨折为55．6%,平均显示率为86．3％。VR图像能够通过图像旋转、切割等功能从不同方向观察骨折的位置、范围、骨碎块的移位,了解骨折线的走行及外伤所致的畸形情况。结论：MPR结合VR成像对面中部骨折的诊断治疗具有很高的临床应用价值。64排螺旋CT图像能提高对深部纲微骨折的显示．     

Hemorrhage in the endolymphatic sac: a cause of hearing fluctuation in enlarged vestibular aqueduct

Objective

Most of the patients with enlarged vestibular aqueduct (EVA) experience sudden hearing deterioration, but the exact mechanism is unclear. We analyzed magnetic resonance (MR) images and the cellular components of endolymph obtained from the endolymphatic sac in patients with EVA, in order to demonstrate the cause of sudden hearing loss.

Methods

A total of 25 patients (50 ears) with EVA, who had severe to profound hearing loss, were included in this retrospective clinical study. MR examinations were performed by a 3.0-T MR system using an 8-channel sensitivity-encoding head coil. We analyzed endolymphatic fluid harvested from the endolymphatic sac during cochlear implantations in four patients.

Results

The area of low signal intensity in the endolymphatic sac was observed on T2-weighted MR images for 15 of 50 ears. This area was observed more frequently in patients who experienced recent sudden hearing loss (10/12, 83%) than those with stable hearing (5/38, 13%)(Fisher's exact test, p < 0.001). In addition, this area showed high signal intensity on fluid attenuated inversion recovery images. Cytologic analysis of the aspirated endolymph from the endolymphatic sac in the patients with this area revealed many erythrocytes.

Conclusion

Our data suggests that hemorrhage in the endolymphatic sac could be a cause of sudden hearing deterioration in patients with EVA.     

人工耳蜗植入术治疗大前庭水管综合征16例临床分析

探讨大前庭水管综合征（LVAS）的发病机制、听力学检查、防治措施。