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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.

Background: There are few studies focused on vestibular symptoms and function of the children with LVAS., Objectives: This study aimed to find the characteristics of air and bone-conducted VEMPs among children with LVAS, and to investigate the relationship between VEMPs and vestibular symptoms., Material and Methods: A total of 44 children with LVAS and 10 healthy children were recruited as the case group and control group. Air and bone-conducted VEMP were performed to the participants., Results: For air-conducted measurement, there was elevated amplitude of cVEMP in case group than control group. There was no significant difference at oVEMP parameters between the case group and control group. For bone-conducted measurement, significantly longer P1 latency and shorter P1-N1 latency of cVEMP were observed among the case group; there were a series of changes in oVEMP parameters among the case group. Logistic regression model revealed that air-conducted oVEMP asymmetric ratio was valuable to predict vestibular symptoms' development among the kids with LVAS., Conclusion: Asymmetric ratio of oVEMP could be used as one predictor of developing vestibular symptoms of the children with LVAS. Applying bone-conducted VEMP as one alternative parameter of vestibular syndrome is novel and will certainly remain an area of continued investigation.

Sopite syndrome, centered around the drowsiness, lethargy, and irritability associated with motion sickness, can be induced by exposure to low-frequency motion. It is known that the vestibular apparatus plays an important role in the pathogenesis of motion sickness, which features several autonomic responses, and we have previously documented increased vestibular modulation of skin sympathetic nerve activity (SSNA) and an increase in skin blood flow associated with nausea. Here, we assessed whether imperceptibly slow sinusoidal motion, sufficient to induce sopite syndrome but not nausea, also modulates SSNA and skin blood flow. Participants were seated upright and exposed to a randomized set of sinusoidal linear accelerations, ranging from 0.03 Hz at 0.5 mG to 0.2 Hz at 5 mG, via a motorized platform. At all frequencies vestibular modulation was greater than the cardiac modulation of SSNA, but cardiac modulation and skin blood flow were both significantly lower during the motion than at baseline. We conclude that sopite syndrome is associated with a marked modulation of sympathetic outflow to the skin and cutaneous vasoconstriction. NEW & NOTEWORTHY Little is known about the autonomic consequences of sopite syndrome-the drowsiness that can be induced by low-amplitude cyclic motion. We recorded skin sympathetic nerve activity (SSNA) in seated participants exposed to slow sinusoidal linear acceleration (0.03-0.2 Hz), which preferentially activates hair cells in the utricular part of the otolithic organs, at amplitudes that generated no sensations of motion. At all frequencies, there was a clear vestibular modulation of SSNA and cutaneous vasoconstriction.

Objectives: We aimed to investigate the relationship between grades of hearing loss and the presence of acoustically evoked short latency negative response (ASNR) in children with large vestibular aqueduct syndrome (LVAS), so as to enhance the reference value of ASNR for the diagnosis of LVAS in children., Methods: Two hundred sixteen ears from 108 patients (aged 4-90 months) diagnosed with bilateral LVAS, with slight to profound hearing loss, were enrolled in the present study from January 2012 to December 2018. All of the cases were diagnosed with LVAS according to high-resolution computed tomography (HRCT) or magnetic resonance imaging (MRI) scans of the inner ears. The auditory brain stem response (ABR) tests were performed on these subjects with click stimulus (ck-ABR), and the ASNRs were detected based on the method recommended by previous studies. The degree of hearing loss for each ear was classified by the estimated pure-tone average (PTA) thresholds, which were calculated according to the ck-ABR thresholds., Results: ASNRs were present in 40.7% (88/216) ears during ck-ABR tests. Both thresholds of ABR (Z = 2.977, p = 0.003) and estimated PTA (Z = 2.977, p = 0.003) were significantly higher in the ASNR absent group than in the ASNR present group. The frequency of not profound hearing impairment (≤80 dB HL) was much higher in the ASNR present group (44/88; 50%) than in the ASNR absent group (40/128; 31.3%) (χ 2  = 7.714, p = 0.005). The results of the logistic regression model, adjusted by cases' age and gender, showed that compared with those ears with profound hearing impairment (>80 dB HL), the not profound impaired ears were associated with a 2.48-fold increased odds of recording ASNR presence in the ck-ABR test [odds ratio (OR) = 2.48, 95% confidence interval (CI): 1.38-4.46, p = 0.003]., Conclusions: Grades of hearing loss affect the presence of ASNR in children with LVAS, and manifesting as cases with not profound hearing impairment showed increased odds of recording ASNR in the ck-ABR test. Furthermore, more studies should be performed imperatively to determine the diagnosis value of ASNR in children with LVAS., (Copyright © 2020. Published by Elsevier B.V.)

Background: numerous researches on the pathological mechanism of Enlarged Vestibular Aqueduct (EVA) syndrome mainly focuses on the genetic characteristics of SLC26A4 gene and the function of its encoding protein, Pendrin. One of the limitations with these explanations is that it does not explain why cerebrospinal fluid pressure can affect clinical manifestations., Objectives: To establish a new approach to explain the clinical manifestations of EVA syndrome with biomechanical method., Material and Methods: 108 cases of EVA syndrome who received cochlear implantation were analyzed retrospectively. A cochlear model was built to reflect the differences of the structure in EVA syndrome with or without Mondini malformation. The CFD software was used to simulate and display the differences in mechanical pathogenic factors to which the model was subjected., Results: EVA syndrome patients with Mondini malformation suffer more mechanical damage from the cerebrospinal fluid pressure due to their structural reason and their symptoms appear earlier and progress faster., Conclusions: Biomechanics is an important aspect of pathological mechanism of EVA syndrome, and it provides a new angle for clinical decision-making.

Enlarged vestibular aqueduct (EVA) is the most frequent inner ear abnormality found on computed tomography in children with sensorineural hearing loss. The effects EVA abnormalities have on electrocochleography (ECochG) are unknown. Positive deflections in summation potential evoked by tone bursts were observed in 3/5 subjects, while a large negative deflection, similar to endolymphatic hydrops (EH), was observed for 2/5 subjects. The presence of an enlarged summation potential, with and without a compound action potential, was observed in response to a broadband click stimulus. Results suggest likely effects of a third window on ECochG responses and presence of EH in EVA., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Purpose The goal of this study was to evaluate differences in the electrode-neuron interface as a function of hearing loss etiology in pediatric cochlear implant (CI) listeners with enlarged vestibular aqueduct (EVA) syndrome and in those with autosomal recessive connexin-26 mutations (DFNB1). Method Fifteen implanted ears (9 participants, 5 ears with EVA, 10 ears with DFNB1) were assessed. Single-channel auditory detection thresholds were measured using broad and spatially focused electrode configurations (steered quadrupolar; focusing coefficients = 0 and 0.9). Cochlear resistivity estimates were obtained via electrode impedances and electrical field imaging. Between-group differences were evaluated using linear mixed-effects models. Results Children with EVA had significantly higher auditory detection thresholds than children with DFNB1, irrespective of electrode configuration. Between-group differences in thresholds were more pronounced on apical electrodes than on basal electrodes. In the apex, electrode impedances and electrical field imaging values were higher for children with EVA than for those with DFNB1. Conclusions The electrode-neuron interface differs between pediatric CI listeners with DFNB1 and those with EVA. It is possible that optimal clinical interventions may depend, in part, on hearing loss etiology. Future investigations with large samples should investigate individualized CI programming strategies for listeners with EVA and DFNB1.

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., (Copyright © 2019. Published by Elsevier B.V.)

In an attempt to develop an animal model of immune mediated Meniere's disease, we have injected lipopolysaccharide (LPS) directly into scala media of guinea pigs and monitored functional and morphological changes over a period of 6 weeks. Depending on the concentration of LPS, changes ranged from moderate-to-severe hearing loss and endolymphatic hydrops with minimal cellular infiltrate or fibrosis, to dense cellular infiltration that filled the scalae. Interestingly, higher concentrations of LPS not only induced severe cellular infiltration, hydrops, and hearing loss, but also a substantial enlargement of the endolymphatic duct and sac. Moreover, LPS injections into perilymph failed to induce hydrops, yet still resulted in cellular infiltration and fibrosis in the cochlea. This suggests that chronic hydrops resulting from an immune challenge of the cochlea may not be due to blockage of the endolymphatic duct and sac, restricting fluid absorption. Furthermore, injecting antigen into endolymph may produce chronic immune-mediated hydrops, and provide a more promising animal model of Meniere's, although animals did not display signs of vestibular dysfunction, and the hearing loss was relatively severe., (Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.)

Objective: To describe the results of a thorough evaluation in a large series of patients with an enlarged vestibular aqueduct (EVA), focusing on vestibular manifestations with etiological considerations., Study Design: Retrospective chart review of patients with EVA., Setting: Tertiary referral center., Patients: A total of 22 EVA patients with a median age of 8 years (6 mo-35 yr) who underwent both audiovestibular and radiologic examinations., Main Outcome Measures: Patient demographics, radiologic findings, audiologic results, vestibular symptoms, findings of neurotologic examinations, and laboratory evaluations were collected and analyzed. Standard descriptive statistics were used to summarize patient characteristics. Subjects who had a history of vertigo attack were categorized as "vestibulopathy group," while subjects without any history of vertigo as "non-vestibulopathy group.", Results: Of the 41 ears included, 37 (90.2%) had hearing loss on initial audiometric evaluations. Among the 22 patients, 14 (63.6%) complained of dizziness. Of the 14 vertiginous patients, seven had recurrent episodes, five had a history of single attack, and two presented with postural imbalances. There were no significant differences between vestibulopathy and non-vestibulopathy groups with regard to the relationship between the development of vestibular symptoms and aqueductal size, hearing threshold, or age at first visit. Four of the 22 (18.2%) patients developed secondary benign paroxysmal positional vertigo (BPPV) and all patients complained of simultaneous decreases in hearing., Conclusions: Our results demonstrate that patients may develop vestibular symptoms during their clinical course, and all patients with an enlarged vestibular aqueduct should be cautioned regarding the potential development of vestibular pathology. Moreover, the non-negligible incidence of secondary BPPV mandates positional tests when evaluating EVA patients with vertigo.

Background: This paper discusses a special kind of a sensory illusion-the Giant Hand illusion-that was experienced during an exercise on a flight simulator equipped with a VR headset. In the first part we describe spatial disorientation and the function of the vestibular apparatus during flight and its consequences. In this part, the sensory illusion simulator used for the experiment is mentioned. In the second part we describe the simulator and test flight. In the third part we discuss data retrieved during simulator flights that are important for explaining the Giant Hand illusion., Case Report: A well-trained pilot experienced the Giant Hand illusion while executing instrument flight rules flight on a simulator. The Giant Hand illusion was detected from the simulation data and confirmed by the pilot afterward., Discussion: The Giant Hand illusion is a rare type of sensory illusion. The pilot falsely evaluated the situation as a malfunction of the aircraft controls. If the pilot had not been informed by the operator that he might have been influenced by the illusion, he would probably have crashed the simulated aircraft. An unrecognized Giant Hand illusion during a flight can lead to fatal consequences. This case report shows the symptoms and data that can be used for early recognition of this type of illusion.Frantis P, Petru A. The Giant Hand illusion experienced on a simulator. Aerosp Med Hum Perform. 2018; 89(6):557-562.

Hearing of eyeball movements has been reported in superior semicircular canal dehiscence (SSCD), but not hearing of eyelid movements. Our main objective was to report the hearing of eyeball and/or eyelid movements in unilateral SSCD. Our secondary objective was to access its specificity to SSCD and discuss the underlying mechanism. Six patients with SSCD who could hear their eyeball and/or eyelid movements were retrospectively reviewed. With the aim of comparisons, eight patients with an enlarged vestibular aqueduct (EVA), who share the same mechanism of an abnormal third window, were questioned on their ability to hear their eyeball and/or eyelid movements. Three patients with SSCD could hear both their eyeball and eyelid movements as a soft low-pitch friction sound. Two patients with SSCD could hear only their eyelid movements, one of whom after the surgery of a traumatic chronic subdural hematoma. The latter remarked that every gently tapping on the skin covering the burr-hole was heard in his dehiscent ear as the sound produced when banging on a drum, in keeping with a direct transmission of the sound to the inner ear via the cerebrospinal fluid. One patient with SSCD, who could hear only his eyeball movements, had other disabling symptoms deserving operation through a middle fossa approach with an immediate relief of his symptoms. None of the eight patients with EVA could hear his/her eyeball or eyelid movements. Hearing of eyeball and/or eyelid movements is highly suggestive of a SSCD and do not seem to occur in EVA. In case of radiological SSCD, clinicians should search for hearing of eyeball and/or eyelid movements providing arguments for a symptomatic dehiscence. The underlying mechanism is discussed particularly the role of a cerebrospinal fluid transmission.

Background and Objectives: Patients with SCL26A4 mutations presenting with Mondini deformity and enlarged vestibular aqueduct (EVA) tend to have comparable residual hearing. Although cochlear implantation (CI) produces good results in this group, deterioration of residual hearing can be an adverse event after surgery due to accompanying cochlear malformation and perilymph leakage during cochleostomy. The purpose of this study was to investigate if CI in patients with SCL26A4 mutations via the round window (RW) approach could achieve preservation of residual hearing, and to evaluate their speech reception with electroacoustic stimulation (EAS)., Subjects and Methods: This is a retrospective chart review of eight patients with bilateral EVA, who were bi-allelic patients with SCL26A4 mutations. CI was performed in all patients by a single surgeon using the RW approach. Audiological results were compared before and after implantation., Results: Additional hearing loss after CI was less than 10 dBHL in five out of eight patients. Average hearing deterioration after CI was 8.75 dB (range, 0-26). Six out of eight patients used EAS mode after CI. The acoustic stimulation frequency ranged from 271 to 438 Hz. Patients showed better speech recognition in quiet and in noise using EAS mode compared with electrical stimulation alone., Conclusions: Preservation of residual hearing could be achieved after CI in patients with the SLC26A4 mutation via the RW approach. For successful preservation of residual hearing, application of newly-developed soft electrode and meticulous surgical is necessary. Our study showed that patients with the SLC26A4 mutation can be good candidates for EAS surgery.

Objective: To analyze and summarize the effect of bilateral large vestibular aqueducts in peripheral vestibular organ function., Methods: Eighteen patients with bilateral large vestibular aqueduct syndrome (LVAS; Study Group) and 18 healthy volunteers (Control Group) were investigated using audiometry, caloric test, sensory organization test (SOT), and vestibular-evoked myogenic potential (VEMP) tests., Results: All 18 patients (36 ears) exhibited sensorineural hearing loss. For cervical VEMP (cVEMP), the Study Group showed lower thresholds (Study Group vs., Control Group: 71.4vs. 75.3dBnHL; p=0.006), N1 latencies (24.1vs. 25.2ms; p=0.026) and shorter P1 (15.3vs. 16.6ms; p=0.003), and higher amplitudes (400.7vs. 247.2µV; p<0.001) than the Control Group. For ocular VEMP (oVEMP), the Study Group had lower thresholds (79.3vs. 81.8dBnHL; p=0.046) and higher amplitudes (40.6vs. 14.4µV; p<0.001) than the Control Group. Fourteen of 16 patients (87.5%) who completed caloric tests had abnormal results, and 10 of 18 patients (55.6%) exhibited abnormal results in SOTs., Conclusions: The hyperfunction of vestibular test in otolithic organs and the hypofunction of vestibular test in semicircular canals, as well as the dysfunction in the balance test were demonstrated in patients with LVAS., Significance: Our findings can help clinicians gain a better understanding of the characteristics of vestibular organ function in patients with LVAS, which can facilitate optimal targeted treatment., (Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: To document the clinical features and associated pure-tone audiometry data in patients with enlargement of the vestibular aqueduct (EVA), and to identify risk factors for fluctuating hearing loss (HL) and vertigo/dizziness in EVA patients., Methods: In this nationwide survey in Japan, a first survey sheet was mailed to 662 board-certified otolaryngology departments to identify the ones treating EVA patients. A second survey sheet, which contained solicited clinical information and the results of the hearing tests, was mailed to all facilities that reported treating EVA cases. We analyzed clinical information, including age at the time of the most recent evaluation, gender, EVA side, age at onset, initial symptoms, precipitating factors, and etiology from survey responses, and assessed 4-frequency (500, 1000, 2000, and 4000Hz) pure-tone average (PTA) from accompanying pure-tone audiometry data. A multivariate logistic regression analysis was utilized to identify the possible risk factors for fluctuating HL and vertigo/dizziness., Results: In total, 513 hospitals (response rate, 77.5%) responded to the first survey, and 113 reported treating patients with EVA. Seventy-nine out of the 113 hospitals (response rate 69.9%) responded to the second survey, and the data of 380 EVA patients were registered and analyzed. Of the 380 patients, 221 (58.2%) were female, suggesting female preponderance. The patient age ranged from 0 to 73 years (mean, 16.7 years; median, 13 years; interquartile range, 6-24 years). EVA was bilateral in 91.1% of the patients (346/380). The most prevalent initial symptom was HL (341/380), followed by vertigo/dizziness/imbalance (34/380). Sudden HL occurred secondary to head trauma in 5.3% of the patients and upper respiratory infection in 5.0%. Pure-tone audiometry showed profound HL (PTA >91dB) in 316 (52.0%) of the 608 ears in the 304 patients tested, and asymmetric HL, defined as >10dB, in 147 (48.4%) of the 304 patients. The mean PTA was 83.7dB (median, 91.3dB; interquartile range, 71.3-103.8dB), and the severity in PTA did not correlate with age. Multivariate logistic regression identified age ≥10 years (compared to age of 0-9 years), bilateral HL (compared to unilateral HL/normal hearing), a history of head trauma, and Pendred syndrome (compared to the other EVA-associated disorders) as significant risk factors for fluctuating HL and/or vertigo/dizziness., Conclusion: The present nationwide survey of 380 EVA patients provided a more precise description of the clinical features, including risk factors for fluctuating HL and vertigo/dizziness., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Objective: To identify the disease-related SLC26A4 mutants in a Chinese Han pedigree associated with Enlarged vestibular aqueduct (EVA)., Methods: EVA diagnosis was based on the family history, clinical examinations, systematically audiometric evaluations, high-resolution computed tomography (HRCT) of the temporal bone, and magnetic resonance imaging (MRI) of inner ear. Sanger sequencing and mutation analysis of the SLC26A4 gene were performed in all members of this family to identify the disease-related SLC26A4 mutants. Mutations in the SLC26A4 gene were compared with 200 ethnically matched control persons to exclude common polymorphism., Results: All members in this family were negative for systemic and thyroid diseases. There were three subjects (I-2, II-2 and II-3) with bilateral sensorineural deafness since childhood. Temporal bone HRCT scans and inner ear MRI showed bilateral enlarged vestibular aqueduct with Mondini malformation in II-2 and II-3. A novel SLC26A4 splice-site mutation c.1001 + 5G > C was identified in compound heterozygosity with the mutation c.919-2A > G in the proband and in II-2. This novel compound heterozygote of two splice site mutations was not found in 200 normal hearing Chinese Han controls., Conclusions: A novel splice site mutation of c.1001 + 5G > C was identified, and the novel compound heterozygote of two splice site mutations, c.1001 + 5G > C and c.919-2A > G, in the SLC26A4 gene has been linked to hearing impairment in EVA patients., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Objectives/hypothesis: To establish the prevalence of abnormal vestibular test findings in children with enlarged vestibular aqueduct (EVA) and determine if these findings correlate with clinical symptoms, radiographic findings (EVA size and laterality), audiometric findings, and genetic testing in these patients., Study Design: Prospective cohort., Methods: Patients 3 to 12 years of age with hearing loss and imaging findings consistent with EVA treated at our tertiary care institution were sequentially enrolled from 2009 to 2011. The following six outcome measurements were analyzed: audiometric findings, EVA laterality, temporal bone measurements, genetic testing, vestibular testing (cervical-evoked myogenic potentials, posturography, rotational chair, and calorics), and vestibular symptoms., Results: Twenty-seven patients with EVA (mean age 9.2 years, 48% female) were enrolled in and completed the study. Vertigo was reported in six patients. Twenty-four of 27 (89%) had at least one abnormal vestibular test result. Midpoint and operculum size correlated with directional preponderance (P = .042 and P = .032, respectively). Also, high-frequency pure tone average (HFPTA) correlated with unilateral weakness (P = .002). Walking at a later age correlated with abnormal posturography results. There was no correlation between EVA laterality and vestibular test findings., Conclusion: We found a high rate of vestibular pathology in children with EVA; however, the prevalence of abnormal vestibular test findings in this patient population was not correlated with vestibular symptoms. Enlarged vestibular aqueduct size, HFPTA, and walking at a later age were correlated with abnormal vestibular test findings. In view of these results, it may be prudent to consider vestibular testing in children with these clinical characteristics., Level of Evidence: 2b. Laryngoscope, 126:2344-2350, 2016., (© 2016 The American Laryngological, Rhinological and Otological Society, Inc.)

Objectives/hypothesis: Pathologic third window lesions, such as superior semicircular canal dehiscence syndrome (SCDS) or large vestibular aqueduct syndrome (LVAS), cause several auditory and vestibular symptoms, which might affect perilymphatic pressure and induce endolymphatic hydrops (EH). In this study, the existence of EH in subjects with SCDS or LVAS was investigated using contrast-enhanced magnetic resonance imaging (MRI)., Study Design: Case series at university hospital., Methods: Seventeen ears from nine subjects who were diagnosed as having SCDS (five ears from three cases) or LVAS (12 ears from six cases) were studied. Ears were evaluated by 3-T MRI performed 4 hours after intravenous injection of gadodiamide hydrate. Imaging data concerning the degree of EH in the cochlea and the vestibule were compared with clinical symptoms and hearing levels for all ears., Results: All ears showed air-bone gaps at low frequencies on pure tone audiometry. None of the subjects with SCDS had episodes of acute sensorineural hearing loss (SNHL) or vestibular symptoms, except for one patient who complained of head vibration induced by loud noise. Conversely, five of six subjects with LVAS had episodes of acute SNHL or vestibular symptoms. Four of five ears with SCDS showed severe EH in the cochlea, and two ears showed mild EH in the vestibule. All ears with LVAS showed mild to severe EH in both the cochlea and vestibule., Conclusions: The present study demonstrated the existence of EH in ears with pathologic third window lesions, which might affect patients' auditory or vestibular symptoms., Level of Evidence: 4 Laryngoscope, 126:1446-1450, 2016., (© 2015 The American Laryngological, Rhinological and Otological Society, Inc.)

Inner ear bone malformations are one cause of profound sensorineural hearing loss. This investigation focused on those affecting the posterior labyrinth, especially enlarged vestibular aqueduct syndrome, which is associated with fluctuating and progressive hearing loss. The objectives of this study were to analyze the behavior of the electrical stimulation, auditory functionality and linguistic development in patients with inner ear malformations involving the posterior labyrinth. The study included ten patients undergoing cochlear implantation (cases: five with enlarged vestibular aqueduct, two with vestibular aqueduct stenosis/aplasia, and three with semicircular canal disorders). Post-implantation, data were gathered on the electrical stimulation threshold and maximum comfort levels and on the number of functioning electrodes. Evaluation of Auditory Responses to Speech (EARS) subtests were used to assess auditory functionality and language acquisition at 6, 12, and 24 months post-implantation. Results were compared with findings in a control group of 28 cochlear implantation patients without these malformations. No significant differences were found between case and control groups in electrical stimulation parameters; auditory functionality subtest scores were lower in cases than controls, although the difference was only statistically significant for some subtests. In conclusion, cochlear implantation patients with posterior labyrinth bone malformations and profound hearing loss, including those with enlarged vestibular aqueduct syndrome, showed no significant difference in electrical stimulation threshold with controls. Although some auditory functionality test results were lower in cases than in controls, cochlear implantation appears to be beneficial for all patients with these malformations.

Objectives/hypothesis: To describe the clinical experience and characterize the outcomes of cochlear implantation (CI) in children with isolated enlarged vestibular aqueduct (IEVA) as compared to children with enlarged vestibular aqueduct (EVA) associated with other bony labyrinth abnormalities., Study Design: Single, tertiary care, institutional retrospective review over 2 decades., Methods: The clinical course and outcomes of 55 children with EVA undergoing CI between 1991 and 2013 were reviewed. Test measures included open and closed set speech perception tests, and various speech and language measures., Results: In 18 children (32.7%), IEVA was the only defect present. In 33 children (60%), EVA occurred concomitantly with incomplete partition type 2 (IP 2) bilaterally, and three children with incomplete partition type 1 bilaterally. Ninety-two percent (51 of 55) occurred bilaterally and had matching bony defects. Mean age of CI was 73.4 months. A statistically significant defect-related and linguistic-status pattern was noted, impacting the timing of implantation: IEVA = 112.8 months, IP 2 = 58.4 months (P < .001), prelingual deafness = 53.8 months, postlingual deafness = 110.8 months (P < .001). Controlling for implant age and hearing loss severity, IEVA children demonstrated superior performance on speech perception tests (8.2 to 20.3 point differences), though statistical significance was inconsistent (P = .01-.40. Performance was also superior in speech and language tests, though statistical significance was never reached (2.9-13.9 point differences; P = .14-.69)., Conclusions: Children with hearing loss secondary to EVA respond meaningfully to cochlear implantation. However, the severity of temporal bone anomalies in these children has clinical relevance., Level of Evidence: 4., (© 2015 The American Laryngological, Rhinological and Otological Society, Inc.)

Objectives: The aim of this study was to assess if large vestibular aqueduct syndrome (LVAS), with the increase in perilymphatic pressure, affects impedance changes over time with different types of Cochlear(®) implant electrode arrays Contour, Straight, and CI 422. To report speech perception outcomes for these cochlear implant recipients., Methods: Retrospective case review of impedance levels and categories of auditory performance. Impedance data were collected at switch on, 1 month, 3, 6, 12, and 24 months after cochlear implantation and compared with control (non-LVAS cochlear implant recipient) data for each array type. Forty-seven patients with exclusive LVAS and no other vestibulocochlear abnormalities or other identifiable cause of deafness were eligible for inclusion in the study., Results: In LVAS patients, there was a significant difference in impedance between the three types of device (P < 0.0001). Time since switch on was associated with a decrease in impedance for all three devices (P < 0.0001). The mean impedance reduced between switch on and 1 month and remained relatively constant thereafter. Sound variation with softening of sounds was seen in four CI 422 (Straight Research Array) recipients due to ongoing fluctuations in electrode compliance., Discussion: For all three array types, there was no significant difference in the mean impedance between the LVAS patients and controls over the first 12 months. In keeping with previous studies cochlear implant recipients with LVAS hear very well through the cochlear implant.

Conclusion: This study suggests that jugular bulb-vestibular aqueduct dehiscence (JBVAD) does not affect the hearing or balance functions of the inner ear., Objectives: Since JBVAD may cause impairment of the inner ear and induce hearing loss, tinnitus, and vertigo, this study was to investigate the effect of JBVAD on hearing and balance., Method: Patients undergoing temporal bone computed tomography (TBCT) scans from May 2013 to December 2013 at a tertiary referral hospital were reviewed. The topographic relationship between the jugular bulb (JB) and the vestibular aqueduct was assessed. The findings were classified as normal when there was always a bony structure between the two structures and as dehiscent when the bony coverage separating the two structures was absent. Clinical data were collected via electronic records and clinical follow-up., Results: A total of 1313 out of 8325 patients were diagnosed with a HJB. Forty-six patients showed JBVAD. The prevalence of dehiscence was 0.6% in patients undergoing temporal bone CT scans and 3.5% in patients with HJB. Of the 46 patients with JBVAD, 23 (50%) had sensorineural hearing loss, three (6.5%) had tinnitus, and two (4.3%) had vertigo. The correlation between JBVAD and these clinical symptoms did not achieve statistical significance.

Objectives: (1) To report the speech perception and intelligibility results of Mandarin-speaking patients with large vestibular aqueduct syndrome (LVAS) after cochlear implantation (CI); (2) to compare their performance with a group of CI users without LVAS; (3) to understand the effects of age at implantation and duration of implant use on the CI outcomes. The obtained data may be used to guide decisions about CI candidacy and surgical timing., Methods: Forty-two patients with LVAS participating in this study were divided into two groups: the early group received CI before 5 years of age and the late group after 5. Open-set speech perception tests (on Mandarin tones, words and sentences) were administered one year after implantation and at the most recent follow-up visit. Categories of auditory perception (CAP) and Speech Intelligibility Rating (SIR) scale scores were also obtained., Results: The patients with LVAS with more than 5 years of implant use (18 cases) achieved a mean score higher than 80% on the most recent speech perception tests and reached the highest level on the CAP/SIR scales. The early group developed speech perception and intelligibility steadily over time, while the late group had a rapid improvement during the first year after implantation. The two groups, regardless of their age at implantation, reached a similar performance level at the most recent follow-up visit., Conclusion: High levels of speech performance are reached after 5 years of implant use in patients with LVAS. These patients do not necessarily need to wait until their hearing thresholds are higher than 90 dB HL or PB word score lower than 40% to receive CI. They can do it "earlier" when their speech perception and/or speech intelligibility do not reach the performance level suggested in this study.

This study aims to assess the diagnostic value of the acoustically evoked short latency negative response (ASNR) during the auditory brainstem response (ABR) test for enlarged vestibular aqueduct (EVA). The ABR test was performed on 175 subjects with severe and profound hearing loss from July 2008 to August 2011. Patients were submitted to high-resolution computed tomography scans for the temporal bone of the inner ear, and were diagnosed with EVA (EVA group; n = 24 cases, 46 ears), no inner ear deformity (no deformity group; n = 136 cases, 272 ears), or other inner ear deformity (other deformities group; n = 15 cases, 29 ears). The prevalence of ASNR was 26/46 ears (56.52 %) in the EVA group, 10/272 ears (3.67 %) in the no deformity group, and 3/29 ears (10.34 %) in the other deformities group. The rate of ASNR in the EVA group was higher than that in other groups (p < 0.05). The rate of ASNR is positively correlated with EVA. Therefore, the recording of ASNRs could be a valuable method for discovering EVA.

Mutations of SLC26A4 are a common cause of human hearing loss associated with enlargement of the vestibular aqueduct. SLC26A4 encodes pendrin, an anion exchanger expressed in a variety of epithelial cells in the cochlea, the vestibular labyrinth and the endolymphatic sac. Slc26a4 (Δ/Δ) mice are devoid of pendrin and develop a severe enlargement of the membranous labyrinth, fail to acquire hearing and balance, and thereby provide a model for the human phenotype. Here, we generated a transgenic mouse line that expresses human SLC26A4 controlled by the promoter of ATP6V1B1. Crossing this transgene into the Slc26a4 (Δ/Δ) line restored protein expression of pendrin in the endolymphatic sac without inducing detectable expression in the cochlea or the vestibular sensory organs. The transgene prevented abnormal enlargement of the membranous labyrinth, restored a normal endocochlear potential, normal pH gradients between endolymph and perilymph in the cochlea, normal otoconia formation in the vestibular labyrinth and normal sensory functions of hearing and balance. Our study demonstrates that restoration of pendrin to the endolymphatic sac is sufficient to restore normal inner ear function. This finding in conjunction with our previous report that pendrin expression is required for embryonic development but not for the maintenance of hearing opens the prospect that a spatially and temporally limited therapy will restore normal hearing in human patients carrying a variety of mutations of SLC26A4., Competing Interests: The authors have declared that no competing interests exist.

Objective: The aim of this study was to describe audiological and radiological characteristics, and other secondary aspects, in a family carrying a T961G mutation in the 12S rRNA mitochondrial gene., Design: Case report., Study Sample: Six members of a family participated in an audiological evaluation that included pure-tone audiometry, immittance tests, auditory brainstem responses (ABR), and otoacoustic emissions (OAE). The radiological evaluation was conducted through temporal bone CT scans using a Toshiba 16 channels Aquilon Spirale. Neuropsychiatric evaluation was also administered., Results: Three participants were diagnosed with severe sensorineural hearing loss of cochlear origin and cochlear malformations visible in CT scans. One participant had a mild mixed-hearing loss and no cochlear malformations. Two participants had normal audiological and radiological findings., Conclusions: We believe our study can provide helpful insight on the clinical findings of a rare mutation, of which few data have been presented in literature.

Objective: To demonstrate the value of recording air-conducted ocular Vestibular Evoked Myogenic Potentials (oVEMP) in a patient with bilaterally enlarged vestibular aqueducts., Design: Cervical VEMP and oVEMP were recorded from a patient presenting with bilateral hearing loss and imbalance, attributable to large vestibular aqueduct syndrome. The stimuli were air-conducted tone bursts at octave frequencies from 250 to 2000 Hz. Amplitudes and thresholds were measured and compared with the normal response range of 32 healthy control subjects., Results: oVEMP reflexes demonstrated pathologically increased amplitudes and reduced thresholds for low-frequency tone bursts. Cervical VEMP amplitudes and thresholds were within normal limits for both ears across all frequencies of stimulation., Conclusions: This study is the first to describe the augmentation of AC oVEMPs in an adult with large vestibular aqueduct syndrome.

Conclusions: Enlarged vestibular aqueduct (EVA) may precipitate secondary benign paroxysmal positional vertigo (BPPV), especially in pediatric populations, as well as paretic dysfunction of the vestibular end organ., Objectives: EVA is characterized by the early onset of sudden or progressive sensorineural hearing loss with or without vestibular dysfunction. However, vestibular dysfunction in patients with EVA has not been described as frequently as hearing loss, and an association with BPPV has not been previously reported. By reviewing the cochleo-vestibular status of three children and two young adults with EVA who had been diagnosed with BPPV, characteristic features of BPPV in EVA patients were investigated and possible pathogenetic mechanisms are speculated., Methods: A retrospective review of medical records was conducted for five patients with EVA who presented with BPPV from January 2004 to July 2009. Clinical courses, characteristics of vertigo and audiovestibular laboratory findings were reviewed., Results: Among 26 patients with radiologically confirmed EVA, 5 (19.2%) exhibited positional nystagmus compatible with BPPV through Dix-Hallpike and head-roll tests. Hearing loss usually accompanied BPPV attacks, and BPPV was recurrent in three patients. Multiple semicircular canals were frequently involved in each episode, and different canals were also involved in recurrent cases. Canalith repositioning procedures were usually successful without difficulty.

Enlargement of the vestibular aqueduct (EVA) is one of the most common inner ear malformations associated with sensorineural hearing loss in children. The delayed onset and progressive nature of this phenotype offer a window of opportunity to prevent or retard progression of hearing loss. EVA is not the direct cause of hearing loss in these patients, but rather is a radiologic marker for some underlying pathogenetic defect. Mutations of the SLC26A4 gene are a common cause of EVA. Studies of an Slc26a4 knockout mouse demonstrate that acidification and enlargement of the scala media are early events in the pathogenesis of deafness. The enlargement is driven by fluid secretion in the vestibular labyrinth and a failure of fluid absorption in the embryonic endolymphatic sac. Elucidating the mechanism of hearing loss may offer clues to potential therapeutic strategies., (Published by Elsevier B.V.)

Mutations in human SLC26A4 are a common cause of hearing loss associated with enlarged vestibular aqueducts (EVA). SLC26A4 encodes pendrin, an anion-base exchanger expressed in inner ear epithelial cells that secretes HCO3- into endolymph. Studies of Slc26a4-null mice indicate that pendrin is essential for inner ear development, but have not revealed whether pendrin is specifically necessary for homeostasis. Slc26a4-null mice are profoundly deaf, with severe inner ear malformations and degenerative changes that do not model the less severe human phenotype. Here, we describe studies in which we generated a binary transgenic mouse line in which Slc26a4 expression could be induced with doxycycline. The transgenes were crossed onto the Slc26a4-null background so that all functional pendrin was derived from the transgenes. Varying the temporal expression of Slc26a4 revealed that E16.5 to P2 was the critical interval in which pendrin was required for acquisition of normal hearing. Lack of pendrin during this period led to endolymphatic acidification, loss of the endocochlear potential, and failure to acquire normal hearing. Doxycycline initiation at E18.5 or discontinuation at E17.5 resulted in partial hearing loss approximating the human EVA auditory phenotype. These data collectively provide mechanistic insight into hearing loss caused by SLC26A4 mutations and establish a model for further studies of EVA-associated hearing loss.

Background: Mutations in SLC26A4 cause Pendred syndrome (hearing loss with goiter) or DFNB4 (non-syndromic hearing loss with inner ear malformation, such as enlarged vestibular aqueduct or Mondini deformity). The relationship between mutations in SLC26A4 and Mondini deformity without enlarged vestibular aqueduct has not been studied in any Chinese deaf population. The purpose of this study was to assess whether mutations in the SLC26A4 gene cause Mondini deformity without an enlarged vestibular aqueduct (isolated Mondini deformity) in a Chinese population., Methods: In total, 144 patients with sensorineural hearing loss were included and subjected to high-resolution temporal bone CT. Among them, 28 patients with isolated Mondini dysplasia (MD group), 50 patients with enlarged vestibular aqueduct with Mondini dysplasia (EVA with MD group), 50 patients with enlarged vestibular aqueduct without Mondini dysplasia (EVA group), and 16 patients with other types of inner ear malformations (IEM group) were identified. The coding exons of SLC26A4 were analyzed in all subjects., Results: DNA sequence analysis of SLC26A4 was performed in all 144 patients. In the different groups, the detection rate of the SLC26A4 mutation differed. In the isolated MD group, only one single allelic mutation in SLC26A4 was found in one patient (1/28, 3.6%). In the EVA with MD group, biallelic and monoallelic SLC26A4 mutations were identified in 46 patients (46/50, 92.0%) and three patients (3/50, 6.0%), respectively. Also, in the EVA group, biallelic and monoallelic SLC26A4 mutations were identified in 46 patients (46/50, 92.0%) and three patients (3/50, 6.0%), respectively. These percentages were identical to those in the EVA plus MD group. Only two patients carried monoallelic mutations of the SLC26A4 gene in the IEM group (2/16, 12.5%). There were significant differences in the frequency of SLC26A4 mutation among the groups (P<0.001). The detection rate of SLC26A4 mutation in the isolated MD group was significantly lower than in the EVA group (with or without MD; P<0.001), and there was no significant difference in the detection rate of SLC26A4 between the MD group and IEM group (P>0.5)., Conclusion: Although mutations in the SLC26A4 gene were frequently found in Chinese EVA patients with and without MD, there was no evidence to show a relationship between isolated MD and the SLC26A4 gene in the Chinese population examined. Hearing impairment in patients with isolated MD may be caused by factors other than mutations in the SLC26A4 gene.

Objectives: To review the controversial aspects of the enlarged vestibular aqueduct syndrome., Study Design: Contemporary review., Methods: A literature search using the terms "enlarged vestibular aqueduct and large vestibular aqueduct" were used to generate the articles for review in this article., Results: The enlarged vestibular aqueduct is a condition causing variable auditory and vestibular dysfunction. Although it has been 32 years since Valvasorri and Clemis recognized the clinical importance of the enlarged vestibular aqueduct, many controversial aspects of the diagnosis remain. The topics reviewed in this discussion are as follows: size criteria for radiographic diagnosis, precipitating factors for hearing loss, corticosteroid treatment and sac surgery, conductive component to hearing loss, natural progression of hearing loss, correlations between aqueduct size and hearing loss, genetics, vestibular symptoms, and theories regarding mechanisms behind the symptoms., Conclusion: The enlarged vestibular aqueduct remains a controversial entity with variable presentation, progression, and prognosis., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.)

Objective: To present the theory that large vestibular aqueduct syndrome (i.e. the recognised existence of an enlarged vestibular aqueduct with progressive sensorineural hearing loss) and endolymphatic hydrops are due to a common primary dysfunction of inner-ear fluid homeostasis., Method: Case report and review of the world literature concerning large vestibular aqueduct syndrome and endolymphatic hydrops., Results: We report a family in which one sibling suffered from large vestibular aqueduct syndrome while the other had classic Ménière's disease. This suggests that large vestibular aqueduct syndrome and endolymphatic hydrops, in some cases, may be due to a common primary dysfunction of inner-ear fluid homeostasis., Conclusion: To our knowledge, this is the first report in the world literature to postulate that variation in the relative compliance of inner-ear membranes could be the factor that determines the manifestation of the disorder as either endolymphatic hydrops or large vestibular aqueduct syndrome.

Objective: To assess the effect of inner ear pressure on middle ear impedance in patients with large vestibular aqueduct syndrome (LVAS)., Methods: Data from admittance tympanometry and multifrequency tympanometry on 8 LVAS patients and control subjects were studied., Results: 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., Conclusion: 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.

Objective: 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., Review Methods: 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., Conclusion: 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.

Objectives: The goal of this study was to characterize the signal intensity (SI) pattern in the endolymphatic duct/sac from T2-weighted spin echo magnetic resonance (MR) images and T2*-weighted 3-dimensional (3-D) constructive interference in steady state (CISS) MR images that were obtained from a homogenous group of patients with an enlarged vestibular aqueduct (EVA) associated with SLC264 (PDS) mutations., Study Design: A retrospective study., Setting: Tertiary referral center., Patients: Eleven subjects (22 ears), with at least 1 SLC26A4 mutation and bilateral EVA confirmed by temporal bone computed tomography, were enrolled., Intervention: The MR images of 22 ears were reviewed retrospectively., Main Outcome Measures: The SI of the endolymphatic sac (ES) from 2 sequences were compared and reviewed. The presence of anomalies of the vestibule were also evaluated. In addition, the caloric test results were also reviewed to characterize the vestibular function in a subset of our cohort (12 ears)., Results: T2*-weighted 3-D CISS MR images revealed a more variable SI in the enlarged endolymphatic system than did the T2-weighted images. There was a hierarchy for the order of SI loss from the endolymphatic system on the T2*-weighted 3-D CISS MR images. There were 3 cases where the SI loss from the intraosseous ES, on the T2*-weighted 3-D CISS images, was associated with an abnormal caloric response., Conclusion: The SI of the ES observed on T2*-weighted 3-D CISS images of EVA patients, with SLC26A4 mutations, showed a distinctive pattern, and the results from this study suggest a potential role for the MR imaging in providing physicians with better information about the functional status of the inner ear.

Children with permanent unilateral or mild bilateral hearing loss have been a focus of concern by audiologists, educators, and physicians for at least 2 decades. These children are known to be at risk for psychoeducational difficulties. However, despite this concern, little has been learned about the causative factors of these hearing losses and how those factors might be contributing to child development. This review of known causes of permanent unilateral and mild bilateral hearing loss in children is meant to draw attention to the importance of the search for etiologic factors. That is, the identification of the hearing loss should not signal the end of the diagnostic process but, rather, the beginning of a search for causation. With the combined efforts of audiologists, otolaryngologists, pediatricians, geneticists, and other medical professionals, we may enhance our understanding of the primary causes of unilateral and mild bilateral hearing loss and, perhaps, create links between causative factors and psychosocial and psychoeducational outcomes.

The vestibular aqueduct is a bony canal related to the bony labyrinth of the inner ear and represents the non-sensory components of the endolymph-filled, closed, membranous labyrinth. The association of congenital sensorineural hearing loss with a large or enlarged vestibular aqueduct is well known as the large vestibular aqueduct syndrome (LVAS). The enlarged VA (EVA) comprises abnormalities not only in the structure of the inner ear, but also in the physiology of the auditory and vestibular systems. The clinical picture of this clinical entity is variable [Yetiser S, Kertment M, Ozkaptan Y. Vestibular disturbance in patients with Large Vestibular Aqueduct Syndrome (LVAS). Acta Otolaryngol (StochK) 1999;119: 641-646]. Signs and symptoms of the auditory impairment are more commonly described in the literature: hearing loss ranges from mild to profound, arising from fluctuating to stepwise progressive or sudden. Vestibular disturbances, ranging from mild imbalance to episodic vertigo, are rarely described in the literature. Benign paroxysmal positional vertigo (BPPV) is a labyrinthine disorder with a typical behavior: intense crises of rotational vertigo induced by postural changes of the head, with short duration and usually good responsiveness to rehabilitative maneuvers. These maneuvers are effective in about 80% of patients with BPPV. BPPV often recurs. About 1/3 of patients have a recurrence in the first year after treatment, and by five years, about half of all patients have a recurrence. Vestibular aqueduct has been demonstrated by conventional tomography and computed tomography (CT), however, CT scans cannot show the membranous labyrinth itself. On MR images it is not the vestibular aqueduct that is visualized but its contents, the endolymphatic duct and sac, and can show the abnormalities of the fluid spaces related to the membranous labyrinth. It is proposed that recurrent benign paroxysmal positional vertigo (BPPV) is related with volumetric abnormalities of vestibular aqueduct. This verifiable hypothesis tries to define this rapport and explore new diagnostic and therapeutic possibilities.

Objectives: Patients with large vestibular aqueduct syndrome (LVAS) often demonstrate an air-bone gap at the low frequencies on audiometric testing. The mechanism causing such a gap has not been well elucidated. We investigated middle ear sound transmission in patients with LVAS, and present a hypothesis to explain the air-bone gap., Methods: Observations were made on 8 ears from 5 individuals with LVAS. The diagnosis of LVAS was made by computed tomography in all cases. Investigations included standard audiometry and measurements of umbo velocity by laser Doppler vibrometry (LDV) in all cases, as well as tympanometry, acoustic reflex testing, vestibular evoked myogenic potential (VEMP) testing, distortion product otoacoustic emission (DPOAE) testing, and middle ear exploration in some ears., Results: One ear with LVAS had anacusis. The other 7 ears demonstrated air-bone gaps at the low frequencies, with mean gaps of 51 dB at 250 Hz, 31 dB at 500 Hz, and 12 dB at 1,000 Hz. In these 7 ears with air-bone gaps, LDV showed the umbo velocity to be normal or high normal in all 7; tympanometry was normal in all 6 ears tested; acoustic reflexes were present in 3 of the 4 ears tested; VEMP responses were present in all 3 ears tested; DPOAEs were present in 1 of the 2 ears tested, and exploratory tympanotomy in 1 case showed a normal middle ear. The above data suggest that an air-bone gap in LVAS is not due to disease in the middle ear. The data are consistent with the hypothesis that a large vestibular aqueduct introduces a third mobile window into the inner ear, which can produce an air-bone gap by 1) shunting air-conducted sound away from the cochlea, thus elevating air conduction thresholds, and 2) increasing the difference in impedance between the scala vestibuli side and the scala tympani side of the cochlear partition during bone conduction testing, thus improving thresholds for bone-conducted sound., Conclusions: We conclude that LVAS can present with an air-bone gap that can mimic middle ear disease. Diagnostic testing using acoustic reflexes, VEMPs, DPOAEs, and LDV can help to identify a non-middle ear source for such a gap, thereby avoiding negative middle ear exploration. A large vestibular aqueduct may act as a third mobile window in the inner ear, resulting in an air-bone gap at low frequencies.

Objective: To investigate and compare the usefulness of preoperative magnetic resonance (MR) imaging and high-resolution temporal bone computed tomography (HRCT) in pediatric cochlear implant candidates., Study Design: Prospective., Setting: Tertiary referral center., Patients: A cohort of 92 pediatric patients with profound hearing. Inclusion criteria were MR, computed tomography, and cochlear implantation. INTERVENTION., Diagnostic: All patients had preoperative imaging of the petrous temporal bone (HRCT, T2-weighted fast spin echo, axial 3D Fast Imaging Employing Steady-state Acquisition [FIESTA] MR) and brain (Fast Fluid-attenuated Inversion-recovery [FLAIR] MR)., Main Outcome Measure(s): Overall prevalence of inner ear dysplasias in this population and comparison of detection rates between HRCT, T2 Fast Spin Echo (FSE), and FIESTA MR sequences., Results: Radiological abnormalities were observed in 32 and 59% of MR and HRCT temporal bone, respectively. Synchronous intracranial findings were noted in 40% on brain MR. Common vestibulocochlear nerve was observed in 3% ears and directed side of implantation. Consistent discrepancies noted on HRCT were inability to diagnose early obliterative labyrinthitis and presence of the cochlear nerve in the internal auditory canal. With respect to MR, enlarged vestibular aqueducts and narrow cochlear nerve canals were consistently under identified., Conclusion: Dual-modality imaging with HRCT and MR of petrous bone and MR brain in the precochlear implant pediatric population detects abnormalities related to deafness, which would not otherwise be found using either modality alone. There is overlap between the imaging modalities in the type of abnormalities detected, and we present a case for selective use of HRCT within a diagnostic algorithm, using the patient risk factors we have identified.

Objectives: : The objectives of this study were to identify SIX1 gene mutations in a patient with branchio-oto syndrome (BO) and to clarify the relationship between SIX1 mutation and enlargement of the vestibular aqueduct (EVA)., Methods: : A genetic study and retrospective chart review for a patient in whom EYA1 mutation had already been excluded was conducted. We studied a Japanese patient who had autosomal-dominant mixed hearing loss, a unilateral ear pit and unilateral EVA, and who was previously diagnosed as having BO. We searched for SIX1 and SLC26A4 mutations using polymerase chain reaction and direct gene sequencing., Results: : The patient carried a heterozygous A-->G mutation at nucleotide 386 within exon 1 of SIX1 that resulted in substitution of a cysteine for a tyrosine at codon 129 (Y129C) of the gene product. Y129C is a previously identified SIX1 mutation and was not detected in any of our 164 control chromosomes. No SLC26A4 mutations were identified., Conclusion: : Y129C mutation in SIX1 may cause EVA as well as BO.

Recessive mutations of PDS gene are the common causes of Pendred syndrome and non-syndromic hearing loss associated with temporal bone abnormalities ranging from isolated enlargement of the vestibular aqueduct (EVA) to Mondini dysplasia. In this study we evaluate the relationship between EVA and Mondini dysplasia in 10 prelingual deaf patients and PDS gene mutation. One of three mutations, IVS7-2A-->G, IVS16-6G-->A or IVS15+5G-->A, was identified in the PDS gene in each patient. In family studies of four probands with the IVS7-2A-->G mutation, we found that this mutation was inherited from the same mutant alleles of parental origin. The effect of IVS7-2A-->G mutation on PDS gene expression was determined by reverse transcription and polymerase chain reaction (RT-PCR). Sequencing of the RT-PCR products revealed that the PDS transcripts from the allele with IVS7-2A-->G mutation lose the entire exon 8, resulting in a joining of exons 7 and 9. Deletion of the exon 8 results in frameshift and premature termination of translation. Haplotype analysis showed a significant haplotype shared among the family members carrying IVS7-2A-->G mutation, suggesting that they may be derived from a common ancestor. Our results provide evidence that hearing loss with EVA and Mondini dysplasia may be caused by splice-site mutation in the PDS gene.

Objective: Case reports indicate that abnormal location of the jugular bulb (JB) may result with some vestibular and audiological symptoms. The aim of this study is to analyze the correlation between the radiological view of the JB and audiovestibular findings and to clarify its possible role for Meniere-like problems., Method: Fifty-six patients, who had abnormal view of the JB on computerized tomography (CT) were selected to the study in this prospective case review. They were classified in three groups (Group-I; Lateral, Group-II; Intermediate and Group-III; Medial), according to the location of the JB. Patients were subjected to audiogram and vestibular tests (Dix-Hallpike maneuver, fistula test, vestibulospinal tests, electronystagmography (ENG))., Results: JB was compressing on the cochlear aqueduct (CA) in two patients in group-II. Seventeen out of 25 patients in group-III had radiological evidence of obstruction of vestibular aqueduct (VA). 19 patients had neurosensorial and four patients had conductive hearing loss. All of the patients in group-I and nine of the patients in group-II gave normal caloric response to stimulation. Twelve of 19 patients in group-III demonstrated canal paresis ranging from 22 to 80%., Conclusion: Present study points out that there is a high correlation between HJB and vestibular problems in symptomatic cases. In patients who have HJB without classic vertigo attacks subclinical involvement of the vestibular system has been observed on ENG recordings. These findings imply that radiological existence of HJB may be a predisposing factor for Meniere-like complaints.

Objective: To characterize audiometric findings in children with a large vestibular aqueduct (LVA)., Design: Retrospective review., Methods: Audiometric records of children with an isolated LVA, diagnosed by computed tomography of the temporal bone, from 1995 through 1998 were reviewed., Results: Nineteen children had an isolated LVA in one or both ears. In all, 26 ears with an isolated LVA were identified. An LVA was seen in association with another inner ear anomaly in an additional 7 ears. The hearing impairment was sensorineural in 22 ears (85%) with an isolated LVA and mixed in 3 (12%). The hearing was normal in 1 ear. The sensorineural hearing impairment (SNHI) was moderate-severe in 12 ears (46%) and severe-profound in 10 ears (38%). Thirteen (50%) of 26 ears had a downsloping or high-frequency SNHI, and 8 (31%) of 26 ears had a midfrequency-peaked audiogram. Bilateral LVAs were seen in 7 children, 6 of whom had bilateral and asymmetrical SNHI. Of 12 patients with a unilateral LVA, 5 had bilateral SNHI., Conclusions: In this series, the children with LVAs typically had moderate-severe or worse SNHI. An unusual midfrequency-peaked audiogram was present in approximately one third of the study patients. The majority of the patients had a unilateral LVA; however, nearly 50% of the patients with a unilateral LVA had bilateral SNHI. The patients with bilateral LVAs generally had asymmetrical SNHI.

Objectives: To describe the chronologic changes of hearing in patients with large vestibular aqueduct syndrome (LVAS) and identify the prognostic factors., Study Design: A retrospective chart-review study., Methods: Twelve consecutive patients with LVAS were recruited at Taipei Veterans General Hospital between July 1986 and July 2000. The records of serial pure-tone audiogram and high-resolution computer tomography were collected. The chronologic figures of pure-tone average (PTA) were sketched. The investigated variables included sex, laterality and type of hearing loss (HL), size of vestibular aqueduct, and the chronologic changes and configurations of hearing. Data were analyzed statistically., Results: The degree of HL in early childhood was from moderate to profound. The worst hearing could be estimated by the hearing level in early childhood. Sixteen of 24 ears were stable. Bilateral, chronologically stepwise-downhill hearing occurred in only one patient (1/12) during the follow-up period. Chronologically, high-tone hearings were worse than those of low-tone, but fluctuations of high-tone hearing were smaller than those of low-tone. The sizes of vestibular aqueduct were predictive of the density of major depression and its depth., Conclusions: LVAS, a congenital disease, is characterized by fluctuating sensorineural HL. Most hearing at PTA remained stable at least in one ear chronologically. The standard deviation of hearing at 500 Hz was the only prognostic factor for the progression of PTA. An enlarged vestibular aqueduct affects fluctuations of hearing, but the pathogenesis of HL still remains unclear and deserves further investigations.

An enlarged vestibular aqueduct (LVA) is a common congenital inner ear anomaly responsible for some unusual vestibular and audiological symptoms. Most of the cases show bilateral early onset and progressive hearing loss in children. The gross appearance on CT scan of the inner ear is generally normal. However, precise measurements of the inner ear components reveal abnormal dimensions, which may account for the accompanying auditory and vestibular dysfunction. Despite extensive studies on hearing and the vestibular apparatus, saccular function is not studied. To our knowledge this is the first report of saccular malfunction in three patients with LVA by means of vestibular evoked myogenic potentials. Conventional audiograms revealed bilateral severe sensorineural hearing loss in two patients and mixed type hearing loss in one patient. Two of the patients complained about vertigo and dizziness but vestibular assessments of the patients showed normal results. The diagnosis had been made by high-resolution CT scans and MR images of the skull that showed LVA in the absence of other anomalies. The VEMP threshold measured from the ear with LVA in two patients with unilateral enlargement of the vestibular aqueduct was 75-80 dB nHL whereas the threshold from normal ears was 95 dB nHL. The third patient with mixed type hearing loss and bilateral LVA had VEMP responses despite a big air-bone gap in the low frequency range. The VEMP in this patient was greater in amplitude and lower in threshold in the operated ear (the patient had a tympanoplasty which did not improve her hearing). These findings and results of other patients with Tullio phenomenon and superior semicircular canal dehiscence, who also showed lower VEMP threshold, confirmed the theory of a 'third window' that allows volume and pressure displacements, and thus larger deflection of the vestibular sensors, which would cause the vestibular organ to be more responsive to sound and pressure changes.

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.

Objectives: In this investigation, we report the outcomes of 14 adults (age >18 y) and 9 children (age <18 y) with radiographically proven large vestibular aqueduct syndrome (LVAS) who received cochlear implants at Indiana University School of Medicine., Study Design: This is a retrospective case-control study detailing the outcomes of 23 patients with LVAS and 46 control patients implanted with Nucleus (Cochlear Corp., Englewood, CO), Clarion (Advanced Bionics Corp., Sylmar, CA), or Med-El (MED-EL Corp., Innsbruck, Austria) cochlear implants., Methods: Performance data on pure-tone averages, speech detection thresholds, and a variety of auditory and speech recognition tasks from these patients with LVAS were compared with performance data obtained from a matched group of 46 cochlear implant users who did not have LVAS. Specific patient characteristics used in matching included the age of the patient, the age at implant of the patient, and whether the patient was pre- or postlingually deafened. Data for the adult group was analyzed using the Student t test, and data for the pediatric patient group was compared using a chi2 test., Results: The results indicated positive outcomes for both pediatric and adult groups. With both adult and pediatric groups, auditory and speech recognition performance did not differ significantly between those patients with LVAS and control subjects., Conclusions: This study adds further support for the use of cochlear implantation in patients with LVAS. Cochlear implantation is beneficial and can be offered as an eventual treatment of LVAS if hearing loss progresses to profound levels in these patients.