Long‐Term Follow‐up of Hearing Loss in Children and Young Adults With Enlarged Vestibular Aqueducts: Relationship to Radiologic Findings and Pendred Syndrome Diagnosis

Colvin, Ian B.; Beale, Timothy; Harrop‐Griffiths, Katherine

doi:10.1097/01.mlg.0000240908.88759.fe

Cited by 77 publications

(81 citation statements)

References 27 publications

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“…An air-bone gap at the low frequencies has been reported to occur in 15% to 100% of patients with LVAS by various authors. [1][2][3][4][5][6][7][8][9][10] The mechanism of an air-bone gap in LVAS remains unclear. Some investigators have suspected fixation, loosening, or discontinuity of the ossicles.…”

Section: Introductionmentioning

confidence: 99%

Clinical Investigation and Mechanism of Air-Bone Gaps in Large Vestibular Aqueduct Syndrome

Merchant

Nakajima²,

Halpin³

et al. 2007

Ann Otol Rhinol Laryngol

133

100

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Objectives-Patients with large vestibular aqueduct syndrome (LVAS) often demonstrate an airbone 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 airbone gap at low frequencies.

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Section: Introductionmentioning

confidence: 99%

Clinical Investigation and Mechanism of Air-Bone Gaps in Large Vestibular Aqueduct Syndrome

Merchant

Nakajima²,

Halpin³

et al. 2007

Ann Otol Rhinol Laryngol

133

100

View full text Add to dashboard Cite

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“…21 Our data concur with previous studies in which measures of signal intensity within the endolymphatic sac did not shown a correlation with the degree of hearing loss. 5 We were particularly interested in the possibility that the presence and occasional rupture of a compartment, with reflux of accumulated debris and metabolites, could be associated with the well-described episodes of sudden or fluctuating hearing loss and vertigo. Sudden hearing loss may be triggered by coryzal illness, trauma, exercise and aeroplane travel, 5 and associated variations in pressure could result in septation rupture and fluid leakage.…”

Section: Discussionmentioning

confidence: 99%

“…endolymphatic sac size, endolymphatic sac T2-weighted magnetic resonance imaging (MRI) signal, and associated labyrinthine anomalies) with patients' audiological findings; however, results have been inconsistent. 4,5,8,9 There have also been limited reports of the presence of internal compartments within large endolymphatic sacs, demonstrated on MRI scans. 4,10,11 However, their significance and their impact on our understanding of the associated hearing loss have not been systematically explored.…”

Section: Introductionmentioning

confidence: 99%

“…4 Alternatively, cerebrospinal fluid pressure fluctuations may be transmitted to the inner ear by the patent endolymphatic sac, resulting in endolymphatic hydrops, perilymphatic fistula or rupture of the cochlear membranes. 1,5 Alternatively, it has been proposed that cerebrospinal fluid pressure is transmitted into the labyrinth through an associated deficient modiolus, or that hearing loss is directly due to such concurrent inner ear anomalies. [5][6][7] There have been attempts to correlate specific anatomical features (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…1,5 Alternatively, it has been proposed that cerebrospinal fluid pressure is transmitted into the labyrinth through an associated deficient modiolus, or that hearing loss is directly due to such concurrent inner ear anomalies. [5][6][7] There have been attempts to correlate specific anatomical features (e.g. endolymphatic sac size, endolymphatic sac T2-weighted magnetic resonance imaging (MRI) signal, and associated labyrinthine anomalies) with patients' audiological findings; however, results have been inconsistent.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic resonance imaging features of large endolymphatic sac compartments: audiological and clinical correlates

et al. 2012

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Objectives: (1) To study the prevalence and characteristics of large endolymphatic sac internal compartments on thin-section T2-and T2*-weighted magnetic resonance imaging, and to relate these to other large endolymphatic sac magnetic resonance imaging features, and (2) to correlate the compartment imaging features, endolymphatic sac size and labyrinthine anomalies with the patients' clinical and audiological data.Method: Magnetic resonance imaging studies for 38 patients with large endolymphatic sac anomalies were retrospectively reviewed in a tertiary referral centre. Endolymphatic sac compartment presence, morphology and imaging signal were assessed. Endolymphatic sac size and labyrinthine anomalies were also recorded. Endolymphatic sac compartments and other imaging features were correlated with clinical and audiological data.Results: Compartments were present in 57 per cent of the imaged endolymphatic sacs, but their presence alone did not correlate with other imaging features or clinical data. The endolymphatic sac : internal auditory meatus signal ratio was associated with a history of sudden or fluctuating hearing loss. Hearing loss correlated with opercular and extraosseous endolymphatic sac size measurements. A larger midpoint intraosseous endolymphatic sac size was associated with clear fluid loss at cochlear implantation.Conclusion: The magnetic resonance imaging characteristics of large endolymphatic sac compartments have been defined. The endolymphatic sac size and distal compartment signal should be recorded, as these provide prognostic information and assist the planning of appropriate interventions.Key words: Hearing Loss; Endolymphatic Sac; Anatomy; Magnetic Resonance IntroductionThe large endolymphatic sac anomaly is a congenital abnormality which results in acquired hearing loss. It is one of the most frequent malformations of the inner ear recognisable on imaging studies.

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SLC26A4 genotype, but not cochlear radiologic structure, is correlated with hearing loss in ears with an enlarged vestibular aqueduct

et al. 2009

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Objectives/Hypothesis Identify correlations among SLC26A4 genotype, cochlear structural anomalies, and hearing loss associated with enlargement of the vestibular aqueduct (EVA). Study Design Prospective cohort survey, National Institutes of Health, Clinical Center, a federal biomedical research facility. Methods 83 individuals, 11 months to 59 years of age, with EVA in at least one ear. Correlations among pure-tone hearing thresholds, number of mutant SLC26A4 alleles, and the presence of cochlear anomalies detected by computed tomography or magnetic resonance imaging. Results Linear mixed-effect model indicates significantly poorer hearing in ears with EVA from individuals with two mutant alleles of SLC26A4 than in those with EVA and a single mutant allele (p = .012) or no mutant alleles (p = .007) in this gene. There was no detectable relationship between degree of hearing loss and the presence of structural cochlear anomalies. Conclusions The number of mutant alleles of SLC26A4, but not the presence of cochlear anomalies, has a significant association with severity of hearing loss in ears with EVA. This information will be useful for prognostic counseling of patients and families with EVA.

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Long‐Term Follow‐up of Hearing Loss in Children and Young Adults With Enlarged Vestibular Aqueducts: Relationship to Radiologic Findings and Pendred Syndrome Diagnosis

Abstract: Patients with EVAs should be advised to avoid known trigger factors for sudden drops in hearing (e.g., minor head trauma). A diagnosis of PS may be associated with a worse audiologic prognosis.

Cited by 77 publications

References 27 publications

Clinical Investigation and Mechanism of Air-Bone Gaps in Large Vestibular Aqueduct Syndrome

Clinical Investigation and Mechanism of Air-Bone Gaps in Large Vestibular Aqueduct Syndrome

Magnetic resonance imaging features of large endolymphatic sac compartments: audiological and clinical correlates

SLC26A4 genotype, but not cochlear radiologic structure, is correlated with hearing loss in ears with an enlarged vestibular aqueduct

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