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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.

Unlabelled: In 1978 Valvassori and Clemis have reported that enlarged vestibular aqueduct can cause progressive perceptive hearing loss and finally deafness., Aim: Analysis of CT scans of patients with cochlear implants. Analysis of radiological data of 120 implanted patients was performed. CT examinations were performed during qualification to cochlear implantation. Most of the CT scans were performed using high resolution computed tomography (HRCT). A special attention was paid to patients with progressive perceptive hearing loss and CT of two patients with "gusher" during CI surgery. In one case (6-years old girl with bilateral profound perceptive hearing loss diagnosed in 2nd year of age) an enlarged vestibular aqueduct was found radiologically. In the second case (16 years old girl with progressive perceptive hearing loss since 1st year of age) no enlarged vestibular aqueduct was detected. Diagnostics and treatment of enlarged vestibular aqueduct syndrome are presented.

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.

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

Large vestibular aqueduct syndrome (LVAS) is a common inner ear anomaly responsible for some unusual vestibular and audiological symptoms. The gross appearance of CT scan of the inner ear is generally normal. However, precise measurement of the inner ear components reveals abnormal dimensions, which may account for accompanying auditory or vestibular dysfunction. It has been reported that sudden increase in cerebrospinal fluid pressure can cause further deterioration of hearing due to transmission of pressure to the inner ear through the enlarged vestibular aqueduct. However, vestibular function is not often studied. In this report, audiovestibular function of 10 patients with large vestibular aqueducts was analysed and compared with the severity of the radiological deformity. The literature was reviewed and typical findings were discussed to emphasize varying aspects of audiovestibular function. It was found that some patients with LVAS have some spontaneous or provoked vestibular disturbance such as vertigo after watching revolving objects. The mean value of electronystagmographic abnormality in patients with hearing loss is greater than in patients with normal hearing. However, there is no statistical correlation between the level of hearing loss, electronystagmographic abnormality and severity of radiological deformity.

The objective of this study was to investigate the effects of endolymphatic sac obliteration for stabilization of progressive hearing loss in patients with the large vestibular aqueduct syndrome. This was a retrospective case review conducted at a private neurootologic office in a metropolitan area. Seven ears in six patients were subjected to surgery for obliteration of the endolymphatic sac in an effort to stabilize progressive hearing loss associated with the large vestibular aqueduct syndrome. The study population was composed of four boys and two girls 4-17 years of age. The large vestibular aqueduct was unilateral in two patients and bilateral in four patients. All seven ears demonstrated progressive sensorineural hearing loss preoperatively. Surgical tissue obliteration was performed via a transmastoid approach in seven ears. The main outcome measure was comparison of pre- and postoperative hearing levels and stability. Magnetic resonance imaging also was performed in all cases at least 6 months postoperatively to determine patency of the endolymphatic sac and vestibular aqueduct. Six of seven ears maintained stable hearing during the follow-up period, which ranged from 6 months to 6 years (mean 3.2 years). One patient showed continued progression of hearing loss postoperatively. All seven ears demonstrated continued obliteration on postoperative imaging studies. Surgical obliteration of the endolymphatic sac may stabilize hearing in patients with the large vestibular aqueduct syndrome and progressive hearing loss. These results support the theory of pressure or fluid reflux into the labyrinth as a cause of progressive hearing loss in these patients.

The large vestibular aqueduct (LVA) syndrome is a congenital malformation that predisposes the patient ultimately to a loss of hearing and possible continuing vestibular disorder. If the LVA patient is diagnosed, it typically is not until later life, when he/she exhibits profound sensorineural hearing loss. To better understand this disorder and to bring it to the attention of audiologists, we provide a brief tutorial of LVA and present three case studies that illustrate the syndrome.

The vein of the vestibular aqueduct in the gerbil runs along the lateral side of the endolymphatic duct, deviates from this course to enter the middle ear cavity, and connects with the lateral sinus. In 20 animals, the vein of the vestibular aqueduct was obliterated by drilling from the middle ear side. Histopathology of these specimens after 2 months' survival revealed consistent sensory cell atrophy in the posterior canal cristae, frequent loss of sensory cells in a small superior portion of the macula sacculi and in the basal end of the cochlea, and fibrosis and osteogenesis in the three semicircular canals. The endolymphatic sacs contained colloidal substances in some specimens which were otherwise normal. Endolymphatic hydrops was absent except in some specimens which showed additional surgical damage to the endolymphatic sac and canals. The blocked vein re-opened occasionally and connected with the vessel formed in new bone from which it attached to the lateral sinus. The sensory cell degeneration and canal fibrosis reflects the pattern of blood drainage by the vein of the vestibular aqueduct. Vascular disorder in the vestibular labyrinth initiates vestibular symptoms; however, it will not produce endolymphatic hydrops unless function of the endolymphatic sac is impaired.

In order to investigate the characteristics of plain radiography of Ménière's disease, the degree of the pneumatization and the distance between the sigmoid plate and the bony wall of the vestibule in Schüller's view were examined in patients with unilateral and bilateral Ménière's disease, non-Ménière vertiginous disease and healthy subjects. There was no difference of the degree of pneumatization and the distance among the patients with Ménière's disease, the non-Ménière inner ear disease group and in healthy subjects. The distance of the unaffected ear was significantly shorter in patients showing a shorter distance of the affected ear. There was no relationship between the distance and age of onset of the disease, and duration of the disease. Therefore, it is concluded that the dysfunction of endolymphatic sac does not always reflect poor mastoid pneumatization and/or shorter distance in the plain radiography and that other etiological mechanisms such as autoimmune disease should be considered in some patients having evidence of endolymphatic hydrops.

Over 250 reports concerning or related to Meniere's disease, published in English from 1978 through 1982, are summarized. Reports have been classified into the categories of incidence of occurrence, analysis and reporting results, pathophysiology, etiologic theories, diagnostic methods, medical management, and surgical procedures. Major emphases in reporting from 1978 though 1982 have been in the areas of pathophysiologic studies, expansion of diagnostic procedures, and the use of sac decompression and neurectomy procedures. This literature review reveals the continuing disagreement regarding the pathophysiology of Meniere's disease and the resultant continued controversies in its management.