Vestibular-evoked myogenic potentials in three patients with large vestibular aqueduct

Sheykholeslami, Kianoush; Schmerber, S.; Kermany, Mohammad Habiby; Kaga, Kimitaka

doi:10.1016/s0378-5955(04)00018-8

Cited by 74 publications

(55 citation statements)

References 25 publications

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“…These various noninvasive tests are helpful in the differential diagnosis of conductive hearing losses, including the diagnostic separation of middle ear causes from inner ear causes of an air-bone gap. [16][17][18][19][20][21][22][23][24][25][26][27] Our results support the idea that the large VA causes an air-bone gap by acting as a mobile third window within the inner ear. We believe that the large VA affects both air conduction and bone conduction, but in a different manner for each pathway.…”

Section: Introductionsupporting

confidence: 83%

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: Introductionsupporting

confidence: 83%

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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“…Furthermore, the presence of bilateral hearing loss in 20% of patients with unilateral EVA and a unilateral hearing loss in 36% of patients with bilateral EVA is proof that structural changes of the temporal bone are not invariably the cause of hearing loss (Fig. 3) (Jackler and De La Cruz 1989;Sheykholeslami et al 2004). As a correlate, these data mean that one proposed mechanism for hearing loss-reXux of hyperosmolar endolymph from the endolymphatic sac and duct into the cochlea-cannot be invariably true (Jackler and De La Cruz 1989), which may explain why endolymphatic sac shunt procedures do not improve hearing (Valvassori and Clemis 1978).…”

Section: Discussionmentioning

confidence: 90%

Genotype–phenotype correlations for SLC26A4-related deafness

et al. 2007

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Pendred syndrome (PS) and non-syndromic enlarged vestibular aqueduct (EVA) are two recessive disorders characterized by the association of sensorineural hearing loss (SNHL) with inner ear malformations that range from isolated EVA to Mondini Dysplasia, a complex malformation that includes a cochlear dysplasia and EVA. Mutations in the SLC26A4 gene, coding for the protein pendrin, have been implicated in the pathophysiology of both disorders. In order to determine whether SLC26A4 genotypes can be correlated to the complexity and severity of the phenotypes, we ascertained 1,506 deaf patients. Inner ear abnormalities were present in 474 patients (32%). Mutation screening of SLC26A4 detected two mutations in 16% of patients, one mutation in 19% of patients and zero mutation in 65% of patients. When the distribution of SLC26A4 genotypes was compared across phenotypes, a statistically significant difference was found between PS patients and non-syndromic EVA-Mondini patients (P = 0.005), as well as between EVA patients and Mondini patients (P = 0.0003). There was a correlation between phenotypic complexity of inner ear malformations and genetic heterogeneity--PS patients have the most severe phenotype and the most homogeneous etiology while EVA patients have the least severe phenotype and the most heterogeneous etiology. For all patients, variability in the degree of hearing loss is seen across genotypes implicating other genetic and/or environmental factors in the pathogenesis of the PS-Mondini-EVA disease spectrum.

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“…38,39 At Massachusetts Eye and Ear Infirmary, 98 patients (165 ears) with EVAS were included in the teaching file from 2000 to 2011. Sixty of 165 ears (36%) demonstrated associated cochleovestibular malformations.…”

Section: -33mentioning

confidence: 99%

Spectrum of Third Window Abnormalities: Semicircular Canal Dehiscence and Beyond

Moonis

Halpin

et al. 2016

AJNR Am J Neuroradiol

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SUMMARY:Third window abnormalities are defects in the integrity of the bony structure of the inner ear, classically producing sound-/ pressure-induced vertigo (Tullio and Hennebert signs) and/or a low-frequency air-bone gap by audiometry. Specific anatomic defects include semicircular canal dehiscence, perilabyrinthine fistula, enlarged vestibular aqueduct, dehiscence of the scala vestibuli side of the cochlea, X-linked stapes gusher, and bone dyscrasias. We discuss these various entities and provide key examples from our institutional teaching file with a discussion of symptomatology, temporal bone CT, audiometry, and vestibular-evoked myogenic potentials.ABBREVIATIONS: EVAS ϭ enlarged vestibular aqueduct syndrome; SSCCD ϭ superior semicircular canal dehiscence

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Vestibular-evoked myogenic potentials in three patients with large vestibular aqueduct

Cited by 74 publications

References 25 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

Genotype–phenotype correlations for SLC26A4-related deafness

Spectrum of Third Window Abnormalities: Semicircular Canal Dehiscence and Beyond

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