Steroid treatment of hearing loss in enlarged vestibular aqueduct anomaly

Hearing loss patterns in enlarged vestibular aqueduct syndrome: Do fluctuations have clinical significance?

OBJECTIVES

To reveal hearing loss patterns in patients with enlarged vestibular aqueduct (EVA) syndrome according to demographic and clinical characteristics.

METHODS

A retrospective, longitudinal study design was utilized to identify patients with EVA. Ears of patients were categorized into one of four cohorts: progressive fluctuating, progressive non-fluctuating, stable fluctuating, and stable non-fluctuating patterns. Pairwise and group comparisons were performed with non-parametric tests to assess vestibular aqueduct (VA) morphology, clinical, and demographic variables between hearing loss pattern cohorts. Rates of hearing loss in the subgroups were determined utilizing a mixed linear effects model.

RESULTS

44 patients (25 female, 19 male, median diagnosis age: 8.06 years) met inclusion criteria. 16 individuals demonstrated unilateral EVA and 29 had bilateral EVA, resulting in 74 total ears with EVA. Amongst the four cohorts, differences in operculum widths amongst groups were statistically significant (p = 0.049) while VA midpoint widths were not (p = 0.522). Progressive hearing loss ears without fluctuations demonstrated a 3.20 dB per year (p < 0.001) progression while progressive hearing loss ears with fluctuations reported a rate of 3.52 dB loss per year (p < 0.001).

CONCLUSION

Hearing fluctuations occur similarly in EVA patients with stable and progressive hearing loss. With the exception of increased rates of hearing loss progression for fluctuating progressive hearing loss patients, vestibular aqueduct morphology, demographic, and clinical characteristics commonly reported are likely not strong predictors for whether patients will or will not experience fluctuating patterns of hearing loss.

Retrospective Review of Midpoint Vestibular Aqueduct Size in the 45° Oblique (Pöschl) Plane and Correlation with Hearing Loss in Patients with Enlarged Vestibular Aqueduct

BACKGROUND AND PURPOSE

Vestibular aqueduct measurements in the 45° oblique (Pöschl) plane provide a reliable depiction of the vestibular aqueduct; however, adoption among clinicians attempting to counsel patients has been limited due to the lack of correlation with audiologic measures. This study aimed to determine the correlation between midpoint vestibular aqueduct measurements in the Pöschl plane in patients with an enlarged vestibular aqueduct with repeat audiologic measures.

MATERIALS AND METHODS

Two radiologists independently measured the midpoint vestibular aqueduct diameter in the Pöschl plane reformatted from CT images in 54 pediatric patients (77 ears; mean age at first audiogram, 5 years) with an enlarged vestibular aqueduct. Four hundred nineteen audiograms were reviewed, with a median of 6 audiograms per patient (range, 3-17; mean time between first and last audiograms, 97.4 months). The correlation between midpoint vestibular aqueduct size and repeat audiologic measures (pure tone average, speech-reception threshold, and word recognition score) using a linear mixed-effects model was determined.

RESULTS

The mean midpoint vestibular aqueduct size was 1.78 mm (range, 0.81-3.46 mm). There was excellent interobserver reliability with intraclass correlation coefficients for the 2 readers measuring 0.92 (P < .001). Each millimeter increase in vestibular aqueduct size was associated with an increase of 10.5 dB (P = .006) in the pure tone average, an increase of 14.0 dB (P = .002) in the speech-reception threshold, and a decrease in the word recognition score by 10.5% (P = .05).

CONCLUSIONS

Midpoint vestibular aqueduct measurements in the Pöschl plane are highly reproducible and demonstrate a significant correlation with audiologic data in this longitudinal study with repeat measures. These data may be helpful for clinicians who are counseling patients with an enlarged vestibular aqueduct using measurements obtained in the Pöschl plane.

Inner-Ear Disorders Presenting with Air-Bone Gaps: A Review

Air-bone gaps (ABGs) are commonly found in patients with conductive or mixed hearing loss generally due to outer- and/or middle-ear diseases such as otitis externa, tympanic membrane perforation, interruption or fixation of the ossicular chain, and chronic suppurative otitis media. ABGs can also be found in correlation with inner-ear disorders, such as endolymphatic hydrops, enlarged vestibular aqueduct syndrome, semicircular canal dehiscence, gusher syndrome, cochlear dehiscence, and Paget disease's as well cerebral vascular anomalies including dural arteriovenous fistula. The typical clinical presentation of inner-ear conditions or cerebral vascular anomalies causing ABGs includes audiological and vestibular symptoms like vertigo, oscillopsia, dizziness, imbalance, spinning sensation, pulsatile or continuous tinnitus, hyperacusis, autophony, auricular fullness, Tullio's phenomenon, and Hennebert's sign. Establishing a definitive diagnosis of the underlying condition in patients presenting with an ABG is often challenging to do and, in many patients, the condition may remain undefined. Results from an accurate clinical, audiological, and vestibular evaluation can be suggestive for the underlying condition; however, radiological assessment by computed tomography and/or magnetic resonance imaging is mandatory to confirm any diagnostic suspicion. In this review, we describe and discuss the most recent updates available regarding the clinical presentation and diagnostic workup of inner-ear conditions that may present together with ABGs.

Enlarged Vestibular Aqueduct Syndrome: Sudden Hearing Loss in a Child with a Cerebral Shunt

Enlarged vestibular aqueduct syndrome (EVAS) is the most common congenital ear anomaly that causes sensorineural hearing loss in children and may predispose a child to sudden hearing loss from sudden pressure changes or minor head trauma. We report a case of a 4-year-old boy with a history of a ventriculoperitoneal shunt and migraines who presented to the emergency department with parental and child care provider reports of acute hearing loss, without a history of trauma, infection, or hardware malfunction, who was diagnosed with bilateral EVAS. Diagnosis of EVAS occurs with specific temporal bone imaging with either high-resolution, thin-cut computed tomography or magnetic resonance imaging scans. Enlarged vestibular aqueduct syndrome is typically refractory to medical treatment and often results in hearing loss that is too severe to benefit from amplification, requiring cochlear implantation.

Developmental changes of ENaC expression and function in the inner ear of pendrin knock-out mice as a perspective on the development of endolymphatic hydrops

Pendrin mutations cause enlarged vestibular aqueducts and various degrees of sensorineural hearing loss. The selective abolition of pendrin causes dilation of the membranous labyrinth known as endolymphatic hydrops, loss of the endocochlear potential, and consequently loss of hearing function. Because Na+ transport is one of the most important driving forces for fluid transport, the epithelial Na+ channel (ENaC) is believed to play an important role in fluid volume regulation in the inner ear. Therefore, the dysfunction of Na+ transport through ENaC by the acidification of endolymph in Pendred syndrome is one of the potential causes of endolymphatic hydrops. We investigated the changes of ENaC expression and function during the development of the pendrin knock-out mouse. In the cochlea, the expression of β and γENaC was significantly increased at P56 in Pds-/- mice compared with Pds+/+ mice. In the vestibule, the expression of βENaC was significantly increased at P56, and γENaC expression significantly increased from P6 to P56 in Pds-/- mice. The ENaC-dependent trans-epithelial current was not significantly different between Pds+/+ and Pds-/- mice in Reissner's membrane or the saccular extramacular roof epithelium at P0, but the current was significantly increased in Pds-/- mice at P56 compared with Pds+/+ mice. These findings indicate that the expression and function of ENaC were enhanced in Pds-/- mice after the development of endolymphatic hydrops as a compensatory mechanism. This result provides insight into the role of Na+ transport in the development and regulation of endolymphatic hydrops due to pendrin mutations.

Cochlear abnormalities associated with enlarged vestibular aqueduct anomaly

OBJECTIVES

The objective of this study is to examine the correlation between enlarged vestibular aqueduct (EVA) anomaly and other inner ear anomalies such as cochlear dysplasia, vestibulocochlear dysplasia and modiolar hypoplasia.

METHODS

Retrospective chart review, with institutional review board approval, of patients with EVA who received treatment at Primary Children's Medical Center or University Hospital at the University of Utah, between 1997 and 2006. Review of radiographs was done to evaluate for the presence of EVA and other inner ear anomalies.

RESULTS

Twenty patients (40 ears) were included in the study, 17 patients had bilateral EVA and three patients had unilateral EVA. There were 10 females and 10 males. The average age of all patients at the time of initial diagnosis was 1.7 years (0-6 years). Thirty-seven ears were shown to have EVA (92.5%). Of those ears with EVA, 29 (78.4%) had one or more inner ear anomalies. Twenty-three (62.2%) ears had cochlear dysplasia, six (16.2%) had vestibulocochlear dysplasia, and 18 (48.7%) had modiolar hypoplasia.

CONCLUSIONS

Using small field of view, thin section CT and/or MR imaging, cochleovestibular abnormalities are commonly identified in association with EVA.