To investigate the morphology and dimensions of the vestibular aqueduct on axial, single-oblique and double-oblique computed tomography images.

The computed tomography temporal bone scans of 112 patients were retrospectively evaluated. Midpoint and opercular measurements were performed using axial, single-oblique and double-oblique images. Morphometric analyses were also conducted. The vestibular aqueduct sizes on axial, single-oblique and double-oblique images were compared.

At the midpoint, the mean (± standard deviation) vestibular aqueduct measured 0.61 ± 0.23 mm, 0.74 ± 0.27 mm and 0.82 ± 0.38 mm on axial, single-oblique and double-oblique images, respectively; at the operculum, the vestibular aqueduct measured 0.91 ± 0.30 mm, 1.11 ± 0.45 mm and 1.66 ± 1.07 mm on the respective images. The co-efficients of variation of the vestibular aqueduct measured at the midpoint were 37.4 per cent, 36.5 per cent and 47.5 per cent on axial, single-oblique and double-oblique images, respectively; at the operculum, the measurements were 33.0 per cent, 40.5 per cent and 64.5 per cent. Regarding morphology, the vestibular aqueduct was fissured (33.5 per cent), tubular (64.3 per cent) or invisible (2.2 per cent).

The morphology and dimensions of the vestibular aqueduct were highly variable among axial, single-oblique and double-oblique images.

Histopathological anomalies of inner-ear structures in individuals with Down syndrome have been well documented; however, few studies have examined the radiological features.

A retrospective study was conducted of temporal bone computed tomography images in 38 individuals (75 ears) with Down syndrome to evaluate the prevalence of inner-ear abnormalities and assess vestibular aqueduct widths.

Inner-ear anomalies were identified in 20 of the 38 individuals (52.6 per cent). Seven of the 75 temporal bones (9.3 per cent) were found to have higher than previously reported. A dilated internal auditory canal and vestibule were more common among the present study group, while prior studies have demonstrated internal auditory canal stenosis and decreased vestibule size.

Down syndrome patients exhibit a high prevalence of dysplastic inner-ear features that confer substantial risk of sensorineural hearing loss. Computed tomography is a useful screening aid to detect inner-ear abnormalities, particularly enlarged vestibular aqueducts, which cause preventable sensorineural hearing loss in this population.

To determine the incidence of high jugular bulb in a group of patients with definite Ménière's disease, and to investigate whether the position or size of the jugular bulb is significantly different in the affected ear than in the unaffected ear.

Retrospective review of patient charts, audiograms, and computed tomography scans to determine the position and size of the jugular bulb in the affected and contralateral ears, as well as other abnormalities.

High jugular bulb was found in 57.1 per cent of affected ears. Encroachment of the cochlear and vestibular aqueducts was apparent in 39.3 per cent and 35.7 per cent, respectively, of affected ears. Diverticulum and dehiscence were observed in 28.6 per cent of affected ears. High jugular bulb was significantly associated with encroachment of the cochlear aqueduct (p = 0.003).

The mediolateral and anteroposterior position of the jugular bulb determines encroachment of the surrounding structures. An abnormal position is postulated to contribute to the development of Ménière's disease.

We report the first use in Australia of hyperbaric oxygen therapy for sudden hearing loss following head trauma in a child with large vestibular aqueduct syndrome.

A 12-year-old boy with large vestibular aqueduct syndrome presented with significant hearing loss following head trauma. He was treated with steroids and hyperbaric oxygen therapy, with good improvement of hearing thresholds on audiography. This case represents the first reported use of hyperbaric oxygen therapy for this indication in Australia, following a few previous reports of patients in Japan. We review the literature on management of acute sensorineural hearing loss in large vestibular aqueduct syndrome. The reported case demonstrates a potentially beneficial therapy for a rare condition that usually results in an inevitable decline in hearing.

Hyperbaric oxygen therapy can be tolerated well by children, and may represent a potential treatment for sudden sensorineural hearing loss in patients with large vestibular aqueduct syndrome.

To review the genotype and cochlear implantation outcome of patients with nonsyndromic hearing loss and enlarged vestibular aqueduct.

Twenty-one Chinese children with nonsyndromic hearing loss and enlarged vestibular aqueduct underwent genetic examination. A DNA microarray was used to screen for the IVS7-2A>G and H723R mutations. Any DNA samples with one or none of the two mutant alleles were sequenced to detect other mutations in the SLC26A4 and FOXI1 genes.

Twelve SLC26A4 mutations were detected, including three novel mutations. The most common mutations detected were IVS7-2A>G and H723R. Twelve patients received cochlear implants, and subsequently demonstrated excellent speech perception.

Three novel mutations were detected in Chinese patients with nonsyndromic hearing loss and enlarged vestibular aqueduct. The SLC26A4 mutation spectrum in the Chinese population is similar to that in other East Asian populations. Cochlear implantation is a safe and effective treatment in patients with enlarged vestibular aqueduct.

To demonstrate the need for computed tomography imaging of the temporal bone before considering revision stapes surgery in patients with recurrent or residual conductive hearing loss.

We report the case of a high-riding jugular bulb with an associated jugular bulb diverticulum, which was dehiscent towards the vestibular aqueduct, in a patient with confirmed otosclerosis who did not experience hearing improvement after stapedotomy.

This case demonstrates the usefulness of temporal bone computed tomography in the evaluation of patients with otosclerosis in whom stapedotomy has not improved hearing. In such patients, revision surgery to address residual hearing loss would eventually prove unnecessary and avoidable.

To demonstrate the need for computed tomography imaging of the temporal bone in patients clinically suspected of otosclerosis who present with atypical symptoms or audiological findings.

We present two patients with bilateral conductive hearing loss and suspected otosclerosis in whom third mobile window lesions were revealed. The first patient had bilateral large vestibular aqueducts and bilateral fenestral otosclerotic foci. Computed tomography imaging of the second case revealed bilateral superior semicircular canal dehiscence and bilateral cochlear clefts, mimicking an otosclerotic focus in the fissula ante fenestram.

Differentiating third mobile window lesions from otosclerosis as the cause of a conductive hearing loss is essential before considering stapes surgery, as such treatment would be unnecessary and potentially harmful.

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.

Case report and review of the world literature concerning large vestibular aqueduct syndrome and endolymphatic hydrops.

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.

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.

The objective of this study was to identify a pattern of signs, symptoms and neuroradiological findings which would assist investigation of vestibular function (especially otolith function) in a group of adult patients with anatomical alterations of the endolymphatic aqueduct and sac.

Fifteen subjects affected by volumetric abnormalities of the vestibular aqueduct were selected from a cohort of patients referred to a tertiary referral neurotological centre between 1 January 2004 and 30 June 2006. All patients underwent accurate clinical history-taking and were evaluated using a standardised set of bedside and instrumental neurotological tests (i.e. audiometry, auditory brainstem response and vestibular evoked myogenic potentials). After these tests, each patient underwent computed tomography and magnetic resonance imaging in order to accurately evaluate the middle ear, labyrinthine capsule and internal auditory canals. These evaluations confirmed clinical suspicion of volumetric abnormalities of the vestibular aqueduct and endolymphatic sac.

All the patients with a defined volumetric alteration in the region of the vestibular aqueduct and endolympatic sac reported a typical pattern of symptoms and signs. The most obvious and frequent symptoms in these patients were migraine-related vertigo (using the Neuhauser criteria, 10 of 15, 66.6 per cent), ‘motion sickness’ (12 of 15, 80 per cent), oscillopsia (nine of 15, 60 per cent) and dizziness (14 of 15, 93.3 per cent). Clinical examination results for the selected patients allowed some useful speculative conclusions. During neurotological evaluation, two instrumental methodologies were especially useful diagnostically: vestibular evoked myogenic potentials of the neck, and the mastoid vibration test at 100 Hz.

Dysfunction of the vestibular aqueduct is suggested by symptomatology characterised by: migraine-related vertigo, unstable or recurring oscillopsia, lowering of the vestibular evoked myogenic potential threshold, hypoacusis, anamnestic report of motion sickness, and nystagmus induced by mastoid vibration and head-shaking. Computed tomography and magnetic resonance imaging are needed in order to confirm clinical suspicions.