Vestibular symptoms in children with enlarged vestibular aqueduct anomaly

The child who lived: Down syndrome among Neanderthals?

Caregiving for disabled individuals among Neanderthals has been known for a long time, and there is a debate about the implications of this behavior. Some authors believe that caregiving took place between individuals able to reciprocate the favor, while others argue that caregiving was produced by a feeling of compassion related to other highly adaptive prosocial behaviors. The study of children with severe pathologies is particularly interesting, as children have a very limited possibility to reciprocate the assistance. We present the case of a Neanderthal child who suffered from a congenital pathology of the inner ear, probably debilitating, and associated with Down syndrome. This child would have required care for at least 6 years, likely necessitating other group members to assist the mother in childcare.

Evidence of vestibular dysfunction in children with enlarged vestibular aqueduct

OBJECTIVE

To investigate the occurrence and characteristics of balance and vestibular deficits in pediatric patients with enlarged vestibular aqueduct (EVA).

MATERIALS AND METHODS

Retrospective review of 53 children with EVA who underwent a comprehensive vestibular evaluation in our pediatric balance and vestibular program. Laboratory testing included videonystagmography (VNG), rotary chair, video head impulse testing (vHIT), vestibular evoked myogenic potential (VEMP), subjective visual vertical (SVV) and Sensory Organization Test (SOT) in posturography.

RESULTS

The mean age of these children, 31 girls and 22 boys, was 7.1 years (SD = 4.8). Among these 53 children, 16 had unilateral EVA (7 on the left side and 9 on the right side) and 37 had bilateral EVA, in which genetic testing confirmed 5 cases of Pendred syndrome. Abnormal testing results were found in 58% (11/19) on SOT, 67% (32/48) on rotary chair, 55% (48/88 of ears) on VEMP, 30% (8/27) on vHIT, 39% (7/18) on SVV, and 8% (4/53) on VNG.

CONCLUSIONS

Vestibular dysfunction may be a common finding in children with EVA. Clinicians who provide medical care for children with EVA need to be familiar with signs of potential balance and vestibular impairments. Although performing vestibular evaluation on young children with EVA can be difficult, objective testing is important in order to identify any potential vestibular deficit in these pediatric patients so that proper vestibular rehabilitation and balance retraining can be provided.

Vestibular anomalies and dysfunctions in children with inner ear malformations: A narrative review

About 20% of children with congenital hearing loss present malformations of the inner ear. In the past few years much has been understood about the morphology and function of the anterior part of the labyrinth, since hearing loss may have a dramatic effect on the overall development of a child. Nowadays, for most of them, a chance for hearing rehabilitation is available, making hearing loss a treatable condition. The anomalies range from the lack of development of the whole inner ear to specific anomalies of isolated structures. Despite the frequent concomitant involvement of the posterior part of the labyrinth, this part of the inner ear is frequently neglected while discussing its morphology and dysfunction. Even though vestibular and balance function/dysfunction may have a significant impact on the global development of children, very little is known about these specific disorders in patients with inner ear malformations. The aim of this review is to summarize the available literature about vestibular anomalies and dysfunctions in children with inner ear malformations, discussing what is currently known about the topic.

Volumetry improves the assessment of the vestibular aqueduct size in inner ear malformation

OBJECTIVES

Enlarged vestibular aqueduct (EVA) is a common finding associated with inner ear malformations (IEM). However, uniform radiologic definitions for EVA are missing and various 2D-measurement methods to define EVA have been reported. This study evaluates VA volume in different types of IEM and compares 3D-reconstructed VA volume to 2D-measurements.

METHODS

A total of 98 high-resolution CT (HRCT) data sets from temporal bones were analyzed (56 with IEM; [cochlear hypoplasia (CH; n = 18), incomplete partition type I (IPI; n = 12) and type II (IPII; n = 11) and EVA (n = 15)]; 42 controls). VA diameter was measured in axial images. VA volume was analyzed by software-based, semi-automatic segmentation and 3D-reconstruction. Differences in VA volume between the groups and associations between VA volume and VA diameter were assessed. Inter-rater-reliability (IRR) was assessed using the intra-class-correlation-coefficient (ICC).

RESULTS

Larger VA volumes were found in IEM compared to controls. Significant differences in VA volume between patients with EVA and controls (p < 0.001) as well as between IPII and controls (p < 0.001) were found. VA diameter at the midpoint (VA midpoint) and at the operculum (VA operculum) correlated to VA volume in IPI (VA midpoint: r = 0.78, VA operculum: r = 0.91), in CH (VA midpoint: r = 0.59, VA operculum: r = 0.61), in EVA (VA midpoint: r = 0.55, VA operculum: r = 0.66) and in controls (VA midpoint: r = 0.36, VA operculum: r = 0.42). The highest IRR was found for VA volume (ICC = 0.90).

CONCLUSIONS

The VA diameter may be an insufficient estimate of VA volume, since (1) measurement of VA diameter does not reliably correlate with VA volume and (2) VA diameter shows a lower IRR than VA volume. 3D-reconstruction and VA volumetry may add information in diagnosing EVA in cases with or without additional IEM.

Clinical Implication of Caloric and Video Head Impulse Tests for Patients With Enlarged Vestibular Aqueduct Presenting With Vertigo

Background: By examining the clinical features and results of video head impulse test (vHIT) and caloric tests in patients with enlarged vestibular aqueduct (EVA) presenting with vertigo, we aimed to investigate the function of angular vestibulo-ocular reflex (VOR) and its clinical implications.

Methods: Nine patients with EVA manifesting with vertigo were enrolled. The medical history, audiological examination, imaging, and the results of the caloric test and the vHIT were analyzed.

Results: Of the nine patients with EVA (eight bilateral and one unilateral case), five were pediatric cases. All 17 ears exhibited sensorineural hearing loss (SNHL). Enlarged vestibular aqueduct patients can present with recurrent (seven cases) or single (two cases) vertigo attack, trauma-induced (two cases), or spontaneous (seven cases) vertigo. Diminished caloric responses were observed in 77.8% (7/9) of the patients (four cases unilaterally and three bilaterally), while unilateral abnormal vHIT results in 11.1% (1/9) patients. Abnormal caloric and normal horizontal vHIT responses were found in 66.7% (6/9) of EVA patients.

Conclusions: Vestibular manifestations in EVA are diverse. Enlarged vestibular aqueduct patients with vertigo can present with a reduced caloric response and normal horizontal vHIT, and this pattern of angular VOR impairment was also found in other hydropic ear diseases.

Systematic Review on Vestibular Symptoms in Patients With Enlarged Vestibular Aqueducts

OBJECTIVE

Enlarged vestibular aqueduct (EVA) is a congenital condition that can lead to various outcomes in pediatric patients including hearing loss and vestibular dysfunction. Our goal was to critically appraise the literature on the proportion of patients with EVA who report vestibular dysfunction, determine relevant risk factors for the development of these symptoms, and describe vestibular tests and interventions used to improve outcomes.

METHODS

A systematic review was performed in accordance with the PRISMA guidelines. We queried the EMBASE, Ovid Medline, and Cochrane Library databases for relevant literature. Studies were included if they had n > 10, reported vestibular symptoms or vestibular function testing in patients with EVA, and were published in English. Nonhuman studies, systematic reviews, and review articles were excluded.

RESULTS

Of 808 identified studies, 20 met inclusion criteria. Subjective vestibular symptoms included dizziness, episodic vertigo, and imbalance. Seventeen studies reported subjective vestibular symptoms, ranging from 2% to 71% of patients between studies. Seventeen studies performed some form of vestibular function test, including physical exam maneuvers (Dix-Hallpike), caloric testing, electronystagmography, and vestibular evoked myogenic potentials. Of those who had vestibular function testing, 7% to 92% had an abnormal result. Two studies identified head trauma as a risk factor. One study successfully treated patients with BPPV using the Epley maneuver, but other vestibular symptoms were not targeted with treatment.

CONCLUSION

The degree to which vestibular symptoms impact patients with EVA varies significantly. Performing vestibular function testing may help identify asymptomatic patients with vestibular dysfunction. Future studies should target improving treatment of vestibular symptoms in EVA patients. Laryngoscope, 2021.

Genetic architecture and phenotypic landscape of SLC26A4-related hearing loss

Mutations of coding regions and splice sites of SLC26A4 cause Pendred syndrome and nonsyndromic recessive hearing loss DFNB4. SLC26A4 encodes pendrin, a transmembrane exchanger of anions and bases. The mutant SLC26A4 phenotype is characterized by inner ear malformations, including an enlarged vestibular aqueduct (EVA), incomplete cochlear partition type II and modiolar hypoplasia, progressive and fluctuating hearing loss, and vestibular dysfunction. A thyroid iodine organification defect can lead to multinodular goiter and distinguishes Pendred syndrome from DFNB4. Pendred syndrome and DFNB4 are each inherited as an autosomal recessive trait caused by biallelic mutations of SLC26A4 (M2). However, there are some EVA patients with only one detectable mutant allele (M1) of SLC26A4. In most European-Caucasian M1 patients, there is a haplotype that consists of 12 variants upstream of SLC26A4, called CEVA (Caucasian EVA), which acts as a pathogenic recessive allele in trans to mutations affecting the coding regions or splice sites of SLC26A4. This combination of an M1 genotype with the CEVA haplotype is associated with a less severe phenotype than the M2 genotype. The phenotype in EVA patients with no mutant alleles of SLC26A4 (M0) has a very low recurrence probability and is likely to be caused by other factors.

Absence of Endolymphatic Sac Ion Transport Proteins in Large Vestibular Aqueduct Syndrome-A Human Temporal Bone Study

HYPOTHESIS

Epithelial ion transport pathologies of the endolymphatic sac (ES) are associated with large vestibular aqueduct syndrome (LVAS).

BACKGROUND

LVAS is defined by the pathognomonic features of a widened bony vestibular aqueduct (VA) and an enlarged ES. The underlying cause of its associated cochleovestibular symptoms remains elusive. Disturbances in epithelial ion transport in the enlarged ES, affecting inner ear fluid regulation, were proposed as a possible pathophysiology. However, although respective epithelial ion transport pathologies have been demonstrated in the enlarged ES from transgenic LVAS mouse models, these pathologies have not been investigated in human LVAS cases.

METHODS

Histological and immunohistochemical analysis of the enlarged ES epithelium in postmortem temporal bones from two individuals with a clinical diagnosis of LVAS.

RESULTS

The enlarged ES epithelium demonstrated an overall atypical epithelial differentiation and a lack of the immunolocalization of signature ion transport proteins. Notably, in both cases, a rudimentary branch of the ES with a typically differentiated ES epithelium was present.

CONCLUSIONS

The described cellular and molecular pathologies of the enlarged ES in humans provide evidence of epithelial transport pathology as one potential cause of cochleovestibular symptoms in LVAS. The present findings also emphasize the clinical relevance of already established LVAS mouse models.

Air and bone-conducted vestibular evoked myogenic potentials in children with large vestibular aqueduct syndrome

BACKGROUND

There are few studies focused on vestibular symptoms and function of the children with LVAS.

OBJECTIVES

This study aimed to find the characteristics of air and bone-conducted VEMPs among children with LVAS, and to investigate the relationship between VEMPs and vestibular symptoms.

MATERIAL AND METHODS

A total of 44 children with LVAS and 10 healthy children were recruited as the case group and control group. Air and bone-conducted VEMP were performed to the participants.

RESULTS

For air-conducted measurement, there was elevated amplitude of cVEMP in case group than control group. There was no significant difference at oVEMP parameters between the case group and control group. For bone-conducted measurement, significantly longer P1 latency and shorter P1-N1 latency of cVEMP were observed among the case group; there were a series of changes in oVEMP parameters among the case group. Logistic regression model revealed that air-conducted oVEMP asymmetric ratio was valuable to predict vestibular symptoms' development among the kids with LVAS.

CONCLUSION

Asymmetric ratio of oVEMP could be used as one predictor of developing vestibular symptoms of the children with LVAS. Applying bone-conducted VEMP as one alternative parameter of vestibular syndrome is novel and will certainly remain an area of continued investigation.

[Enlarged vestibular aqueduct syndrome-dehiscence syndromes-honeycomb mastoid : Pathophysiology and evidence for clinical differentiation]

BACKGROUND

Differential diagnosis of dizziness with hearing loss requires standardized procedures for detection and classification of rare congenital and acquired malformations of the petrous part of the temporal bone.

OBJECTIVE

The aim of this study was to present the physiology and pathophysiology of endolymphatic and perilymphatic pressure regulation, diagnostic guidelines, and aspects of prognosis and treatment.

MATERIALS AND METHODS

Relevant publications and guidelines were evaluated and own cases are reported.

RESULTS

Enlarged vestibular aqueduct (EVA) is the most frequently observed malformation of the inner ear, which leads to increased internal hydrostatic pressure and cochleovestibular dysfunction. Non-syndromic and syndromic forms, e.g., Pendred syndrome, are known. Other pressure-relevant malformations are semicircular canal dehiscence syndrome (SCDS) and enlargement of the cochlear aqueduct. There are currently no treatment options for EVAS and enlarged cochlear aqueduct. Pendred syndrome generally requires treatment with cochlea implants (CI) in early childhood. Dizziness and autophony in patients with SCDS syndrome can be effectively treated by semicircular canal occlusion and coverage.

CONCLUSION

Complaints in non-syndromic EVA and SCD syndrome are mainly caused by exposure of the inner ear to provoked and spontaneous pressure increases. Deafness and vestibular dysfunction in syndromic EVA (i.e., Pendred syndrome, branchiootorenal syndrome) are caused by malformation of the cochlea, genetic maldevelopment of the hair cells, and pressure effects.

Enlarged vestibular aqueduct and Mondini Malformation: audiological, clinical, radiologic and genetic features

PURPOSE

When referring to enlarged vestibular aqueduct (EVA) we should differentiate between nonsyndromic enlarged vestibular aqueduct (NSEVA) and Pendred Syndrome (PDS), a disease continuum associated with pathogenic sequence variants of Pendrin's Gene (SLC26A4) in about half of the cases. The study was aimed to analyse the clinical and audiological features of a monocentric cohort of Caucasian patients with NSEVA/PDS, their genetic assessment and morphological inner ear features.

METHODS

We retrospectively reviewed the audiologic, genetic and anamnestic data of 66 patients with NSEVA/PDS followed by our audiology service.

RESULTS

SLC26A4 mutations was significantly correlated with the presence of PDS rather than NSEVA (p < 0.019), with the expression of inner ear malformations (p < 0.001) and with different severity of hearing loss (p = 0.001). Furthermore, patients with PDS showed significantly worse pure tone audiometry (PTA) than patients with NSEVA (p = 0.001). Anatomically normal ears presented significantly better PTA than ears associated with Mondini Malformation or isolated EVA (p < 0.001), but no statistically significative differences have been observed in PTA between patients with Mondini Malformation and isolated EVA.

CONCLUSION

NSEVA/PDS must be investigated in all the congenital hearing loss, but also in progressive, late onset, stepwise forms. Even mixed or fluctuating hearing loss may constitute a sign of a NSEVA/PDS pathology. Our findings can confirm the important role of SLC26A4 mutations in determining the phenotype of isolated EVA/PDS, both for the type/degree of the malformation, the hearing impairment and the association with thyroid dysfunction.

Torticollis in children with enlarged vestibular aqueducts

OBJECTIVES

To evaluate the association between torticollis and enlarged vestibular aqueduct (EVA).

METHODS

An online/phone survey was administered to parents of 133 children diagnosed with the following disorders: EVA, GJB2 (Connexin 26) mutations associated congenital hearing loss and epistaxis (control). The survey included questions regarding symptoms of torticollis, vertigo, and hearing loss.

RESULTS

Patients with EVA had a 10-fold greater odds of having torticollis than controls (31% vs. 4%; OR = 10.6; 95% CI: 2.9, 39.2). No patients with GJB2 had a reported history of torticollis. Torticollis preceded the diagnosis of hearing loss in most (87%) patients with EVA who had a reported history of torticollis. EVA patients were more likely to have reported motor delay than controls (40% vs. 15%; p = 0.002). EVA patients with prior torticollis (80%; 12/15) were more likely to have balance impairment than EVA patients without prior torticollis (12%; 4/33; p < 0.001). Twelve patients had a reported history of paroxysmal torticollis, all of whom had EVA.

CONCLUSION

Torticollis in infants may be a marker of EVA. Infants with torticollis should be monitored closely for hearing loss and motor delay, especially when the torticollis is paroxysmal.

Fluctuating Sensorineural Hearing Loss

BACKGROUND

Several otologic conditions can present with fluctuating sensorineural hearing loss, including Ménière's disease, autoimmune inner ear disease, and enlarged vestibular aqueduct. Although these 3 etiologies vary greatly, distinguishing between these conditions at initial presentation can be challenging. Furthermore, initial treatment of these conditions is often similar. In this review, we discuss historical and current perspectives on diagnosis and treatment of these conditions.

SUMMARY

A literature search was performed regarding fluctuating hearing loss, and current treatment of these etiologies of fluctuating hearing loss was summarized. Immediate measures at the onset of acute hearing loss include corticosteroid therapy, while preventative and chronic therapies, which can limit disease severity and frequency, vary based on the specific condition treated. Key Messages: Fluctuating hearing loss can represent a range of pathologies, but the precise etiology may not be clear at initial presentation. Timely treatment and long-term follow-up, along with appropriate diagnostics, are necessary to optimize long-term hearing.

Functional Testing of SLC26A4 Variants-Clinical and Molecular Analysis of a Cohort with Enlarged Vestibular Aqueduct from Austria

The prevalence and spectrum of sequence alterations in the SLC26A4 gene, which codes for the anion exchanger pendrin, are population-specific and account for at least 50% of cases of non-syndromic hearing loss associated with an enlarged vestibular aqueduct. A cohort of nineteen patients from Austria with hearing loss and a radiological alteration of the vestibular aqueduct underwent Sanger sequencing of SLC26A4 and GJB2, coding for connexin 26. The pathogenicity of sequence alterations detected was assessed by determining ion transport and molecular features of the corresponding SLC26A4 protein variants. In this group, four uncharacterized sequence alterations within the SLC26A4 coding region were found. Three of these lead to protein variants with abnormal functional and molecular features, while one should be considered with no pathogenic potential. Pathogenic SLC26A4 sequence alterations were only found in 12% of patients. SLC26A4 sequence alterations commonly found in other Caucasian populations were not detected. This survey represents the first study on the prevalence and spectrum of SLC26A4 sequence alterations in an Austrian cohort and further suggests that genetic testing should always be integrated with functional characterization and determination of the molecular features of protein variants in order to unequivocally identify or exclude a causal link between genotype and phenotype.

Position of the Internal Aperture of Vestibular Aqueduct in Patients With Enlarged Vestibular Aqueduct

OBJECTIVE

To investigate the position of the internal aperture of vestibular aqueduct and its relationship to hearing level in patients with enlarged vestibular aqueduct (EVA).

METHODS

The size of the common crus and the position of the internal aperture of vestibular aqueduct were compared among control subjects, EVA patients with and without other inner ear malformations. Auditory steady-state response thresholds were compared between EVA patients with different positions of internal apertures.

RESULTS

The common crus in EVA patients was shorter than in control subjects (p < 0.05). The internal aperture of the vestibular aqueduct opened solely into the common crus in control subjects, simultaneously into the common crus and vestibule in almost 45% of EVA patients, solely into the common crus, and the vestibule in almost 30 and 25% of EVA patients, respectively. Auditory steady-state response thresholds at 2000 and 4000 Hz were higher in EVA patients whose internal apertures of vestibular aqueducts opened simultaneously into the common crus and vestibule than in those whose internal apertures opened solely into the common crus.

CONCLUSION

The common crus is shorter in EVA patients than in control subjects. The internal aperture of the vestibular aqueduct opens solely into the common crus in control subjects. It opens simultaneously into the common crus and vestibule in almost half of the EVA patients. The EVA patients whose internal apertures of vestibular aqueducts open solely into the common crus may have better hearing than those whose internal apertures open simultaneously into the common crus and vestibule.

Congenital hearing loss

Congenital hearing loss (hearing loss that is present at birth) is one of the most prevalent chronic conditions in children. In the majority of developed countries, neonatal hearing screening programmes enable early detection; early intervention will prevent delays in speech and language development and has long-lasting beneficial effects on social and emotional development and quality of life. A diagnosis of hearing loss is usually followed by a search for an underlying aetiology. Congenital hearing loss might be attributed to environmental and prenatal factors, which prevail in low-income settings; congenital infections, particularly cytomegalovirus infection, are also a common risk factor for hearing loss. Genetic causes probably account for the majority of cases in developed countries; mutations can affect any component of the hearing pathway, in particular, inner ear homeostasis (endolymph production and maintenance) and mechano-electrical transduction (the conversion of a mechanical stimulus into electrochemical activity). Once the underlying cause of hearing loss is established, it might direct therapeutic decision making and guide prevention and (genetic) counselling. Management options include specific antimicrobial therapies, surgical treatment of craniofacial abnormalities and implantable or non-implantable hearing devices. An improved understanding of the pathophysiology and molecular mechanisms that underlie hearing loss and increased awareness of recent advances in genetic testing will promote the development of new treatment and screening strategies.

Vestibular pathology in children with enlarged vestibular aqueduct

OBJECTIVES/HYPOTHESIS

To establish the prevalence of abnormal vestibular test findings in children with enlarged vestibular aqueduct (EVA) and determine if these findings correlate with clinical symptoms, radiographic findings (EVA size and laterality), audiometric findings, and genetic testing in these patients.

STUDY DESIGN

Prospective cohort.

METHODS

Patients 3 to 12 years of age with hearing loss and imaging findings consistent with EVA treated at our tertiary care institution were sequentially enrolled from 2009 to 2011. The following six outcome measurements were analyzed: audiometric findings, EVA laterality, temporal bone measurements, genetic testing, vestibular testing (cervical-evoked myogenic potentials, posturography, rotational chair, and calorics), and vestibular symptoms.

RESULTS

Twenty-seven patients with EVA (mean age 9.2 years, 48% female) were enrolled in and completed the study. Vertigo was reported in six patients. Twenty-four of 27 (89%) had at least one abnormal vestibular test result. Midpoint and operculum size correlated with directional preponderance (P = .042 and P = .032, respectively). Also, high-frequency pure tone average (HFPTA) correlated with unilateral weakness (P = .002). Walking at a later age correlated with abnormal posturography results. There was no correlation between EVA laterality and vestibular test findings.

CONCLUSION

We found a high rate of vestibular pathology in children with EVA; however, the prevalence of abnormal vestibular test findings in this patient population was not correlated with vestibular symptoms. Enlarged vestibular aqueduct size, HFPTA, and walking at a later age were correlated with abnormal vestibular test findings. In view of these results, it may be prudent to consider vestibular testing in children with these clinical characteristics.

LEVEL OF EVIDENCE

2b. Laryngoscope, 126:2344-2350, 2016.

Evaluation of the radiological criteria to diagnose large vestibular aqueduct syndrome

OBJECTIVE

The main objective of the current work is to increase the sensitivity of the radiological diagnosis of the large vestibular aqueduct syndrome (LVAS). The specific aims were to compare between the two famous criteria to diagnose large vestibular aqueduct (LVA), (i.e., Valvassori and Cincinnati), to correlate between vestibular aqueduct (VA) measurements in the axial view and those in 45° oblique reformate in children with LVAS, and to define radiological criteria to diagnose LVA in the 45° oblique reformate.

METHODS

The study group included 61 children with LVAS according to Cincinnati criteria (greater than 0.9mm at the midpoint or greater than 1.9mm at the operculum in the axial view). All participants were subjected to full Audiological evaluation and CT scanning in axial plane. The axial data were then transferred to workstation for post-processing with 3D reformatting software (Baxara 3D) in order to obtain the 45° oblique reformates. VA measurements were done at 4 points: midpoint and operculum in both the axial plane and the 45° oblique reformate.

RESULTS

Only 81% of ears of children with LVAS (99 ears) fit Valvassori criterion (i.e., larger than 1.5mm at midpoint), while 19% (23 ears) of them were missed. There were statistically significant correlations among the diameters of the VA in the axial view (both in the midpoint and operculum) and their counterparts in the 45° oblique reformate. Values equal to or greater than 1.2mm in the midpoint and 1.3mm in the operculum are proposed to be the criteria to diagnose LVA in the 45° oblique reformate. Finally, no significant correlations were found between the degree of hearing loss and VA diameters at the axial or 45° oblique reformate.

CONCLUSION

Cincinnati criteria are more sensitive than Valvassori criterin in the diagnosis of LVAS. We recommend the application of Cincinnati criteria instead of Valvassori criteria in order not miss cases with LVAS. Measurement of VA in the 45° oblique reformate is a reliable method to diagnose LVA. Criteria to diagnose LVA in the 45° oblique reformate were proposed.

Optimizing CT for the evaluation of vestibular aqueduct enlargement: Inter-rater reproducibility and predictive value of reformatted CT measurements

Enlarged vestibular aqueduct (EVA), the most frequent identifiable cause of congenital hearing loss, is evaluated with high-definition multi-detector CT in the axial plane. Our purpose was to determine which reformatted CT measurements are most reproducible. Seven multiplanar reformatted images were created for each of the 64 temporal bones in patients with EVA. Intraclass correlation coefficients (ICC) were used to assess inter-observer variability, and both linear regression and ROC analyses were used to compare the measurements with severity of hearing loss, as assessed by pure tone audiometry. All seven measurements had excellent inter-observer variability, with average-measure ICC ranging from 0.92 to 0.98. There was no statistically significant correlation between the radiologic degree of aqueduct enlargement and severity of hearing loss using any of the seven measurements; ROC analyses revealed areas under the curves ranging from 0.57 to 0.73. Optimal accuracy was obtained with a threshold of 1.75 mm as measured at the aqueductal aperture in the Pöschl plane, with sensitivity of 0.75 and specificity of 0.63. Although the radiologic measurement may not serve as a reliable tool for assessing severity of EVA, Pöschl plane reformatting has proven to be better than conventional axial acquisition plane for identifying patients with clinically significant hearing loss.

The effect of jugular bulb-vestibular aqueduct dehiscence on hearing and balance

CONCLUSION

This study suggests that jugular bulb-vestibular aqueduct dehiscence (JBVAD) does not affect the hearing or balance functions of the inner ear.

OBJECTIVES

Since JBVAD may cause impairment of the inner ear and induce hearing loss, tinnitus, and vertigo, this study was to investigate the effect of JBVAD on hearing and balance.

METHOD

Patients undergoing temporal bone computed tomography (TBCT) scans from May 2013 to December 2013 at a tertiary referral hospital were reviewed. The topographic relationship between the jugular bulb (JB) and the vestibular aqueduct was assessed. The findings were classified as normal when there was always a bony structure between the two structures and as dehiscent when the bony coverage separating the two structures was absent. Clinical data were collected via electronic records and clinical follow-up.

RESULTS

A total of 1313 out of 8325 patients were diagnosed with a HJB. Forty-six patients showed JBVAD. The prevalence of dehiscence was 0.6% in patients undergoing temporal bone CT scans and 3.5% in patients with HJB. Of the 46 patients with JBVAD, 23 (50%) had sensorineural hearing loss, three (6.5%) had tinnitus, and two (4.3%) had vertigo. The correlation between JBVAD and these clinical symptoms did not achieve statistical significance.

Vestibular Dysfunction in Patients with Enlarged Vestibular Aqueduct

OBJECTIVE

Enlarged vestibular aqueduct (EVA) is the most common inner ear malformation. While a strong correlative relationship between EVA and hearing loss is well established, its association with vestibular dysfunction is less well understood. In this study, we examine the effects of EVA on the vestibular system in patients with EVA.

STUDY DESIGN

Prospective, cross-sectional study of a cohort ascertained between 1999 and 2013.

SETTING

National Institutes of Health Clinical Center, a federal biomedical research facility.

SUBJECTS AND METHODS

In total, 106 patients with unilateral or bilateral EVA, defined as a midpoint diameter greater than 1.5 mm, were referred or self-referred to participate in a study of the clinical and molecular aspects of EVA. Clinical history was ascertained with respect to the presence or absence of various vestibular signs and symptoms and history of head trauma. Videonystagmography (VNG), cervical vestibular evoked myogenic potential (cVEMP), and rotational vestibular testing (RVT) were performed to assess the vestibular function.

RESULTS

Of the patients with EVA, 45% had vestibular signs and symptoms, and 44% of tested patients had abnormal VNG test results. An increased number of vestibular signs and symptoms was correlated with the presence of bilateral EVA (P = .008) and a history of head injury (P < .001). Abnormal VNG results also correlated with a history of head injury (P = .018).

CONCLUSION

Vestibular dysfunction is common in patients with EVA. However, not all patients with vestibular signs and symptoms have abnormal vestibular test results. Clinicians should be aware of the high prevalence of vestibular dysfunction in patients with EVA.

Nystagmus in Enlarged Vestibular Aqueduct: A Case Series

Enlarged vestibular aqueduct (EVA) is one of the commonly identified congenital temporal bone abnormalities associated with sensorineural hearing loss. Hearing loss may be unilateral or bilateral, and typically presents at birth or in early childhood. Vestibular symptoms have been reported in up to 50% of affected individuals, and may be delayed in onset until adulthood. The details of nystagmus in patients with EVA have not been previously reported.

The objectives were to describe the clinical history, vestibular test findings and nystagmus seen in a case series of patients with enlarged vestibular aqueduct anomaly.

Chart review, included computed tomography temporal bones, infrared nystagmography with positional and positioning testing, caloric testing, rotary chair and vibration testing.

Clinical history and nystagmus varied among the five patients in this series. All patients were initially presumed to have benign paroxysmal positional vertigo, but repositioning treatments were not effective, prompting referral, further testing and evaluation. In three patients with longstanding vestibular complaints, positional nystagmus was consistently present. One patient had distinct recurrent severe episodes of positional nystagmus. Nystagmus was unidirectional and horizontal. In one case horizontal nystagmus was consistently reproducible with seated head turn to the affected side, and reached 48 d/s. Nystagmus associated with enlarged vestibular aqueduct is often positional, and can be confused with benign paroxysmal positional vertigo. Unexplained vestibular symptoms in patients with unilateral or bilateral sensorineural hearing loss should prompt diagnostic consideration of EVA.

Significance of unilateral enlarged vestibular aqueduct

OBJECTIVES/HYPOTHESIS

To describe the clinical phenotype of pediatric patients with unilateral enlarged vestibular aqueduct (EVA) and then to compare the findings to two clinically related phenotypes: bilateral EVA and unilateral hearing loss without EVA. In view of clinical observations and previously published data, we hypothesized that patients with unilateral EVA would have a much higher rate of contralateral hearing loss than patients with unilateral hearing loss without EVA.

STUDY DESIGN

Retrospective cohort study.

METHODS

Patients with unilateral or bilateral EVA were identified from a database of children with sensorineural hearing loss who were seen at a tertiary care institution between 1998 and 2010. Those with imaging findings consistent with well-established EVA criteria were identified. A comparative group of patients with unilateral hearing loss without EVA was also identified. The following specific outcome measurements were analyzed: 1) hearing loss phenotype, 2) laterality of EVA and hearing loss, 3) midpoint and operculum vestibular aqueduct measurements, and 4) genetic test results.

RESULTS

Of the 144 patients who met our inclusion criteria, 74 (51.4%) had unilateral EVA. There was a strong correlation between the presence of hearing loss and ears with EVA. Fifty-five percent of patients with unilateral EVA had hearing loss in the contralateral ear; in most of these patients, the hearing loss was bilateral. Contralateral hearing loss occurred in only 6% of patients with unilateral hearing loss without EVA. No significant differences were found in temporal bone measurements between the ears of patients with unilateral EVA and ipsilateral hearing loss and all ears with EVA and normal hearing (P = .4). There was no difference in the rate of hearing loss progression in patients with unilateral EVA between ears with or without EVA (16 of 48 [33.3%] vs. 9 of 27 [33.3%], respectively; P = 1.0). There was no difference in the rate of hearing loss progression in patients with bilateral and unilateral EVA (41 of 89 ears [46.1%] vs. 25 of 75 ears [33.3%], respectively; P = .1); however, both EVA groups had higher rates of progression compared to patients with unilateral hearing loss without EVA. There was a strong correlation between the presence of hearing loss at 250 Hz and the risk of more severe hearing loss and progressive hearing loss. Patients with bilateral EVA and SLC26A4 mutations had a higher rate of progression than patients who had no mutations (P = .02). No patients with unilateral EVA had Pendred syndrome.

CONCLUSIONS

Children with unilateral EVA have a significant risk of hearing loss progression. Hearing loss in the ear contralateral to the EVA is common, suggesting that unilateral EVA is a bilateral process despite an initial unilateral imaging finding. In contrast to bilateral EVA, unilateral EVA is not associated with Pendred syndrome and may have a different etiology. Temporal bone measurements, hearing loss severity, and hearing loss at 250 Hz were all correlated with the risk of progressive hearing loss. Clinicians should become knowledgeable regarding the implications of this disease process so that families can be counseled appropriately.

Enlarged vestibular aqueduct may precipitate benign paroxysmal positional vertigo in children

CONCLUSIONS

Enlarged vestibular aqueduct (EVA) may precipitate secondary benign paroxysmal positional vertigo (BPPV), especially in pediatric populations, as well as paretic dysfunction of the vestibular end organ.

OBJECTIVES

EVA is characterized by the early onset of sudden or progressive sensorineural hearing loss with or without vestibular dysfunction. However, vestibular dysfunction in patients with EVA has not been described as frequently as hearing loss, and an association with BPPV has not been previously reported. By reviewing the cochleo-vestibular status of three children and two young adults with EVA who had been diagnosed with BPPV, characteristic features of BPPV in EVA patients were investigated and possible pathogenetic mechanisms are speculated.

METHODS

A retrospective review of medical records was conducted for five patients with EVA who presented with BPPV from January 2004 to July 2009. Clinical courses, characteristics of vertigo and audiovestibular laboratory findings were reviewed.

RESULTS

Among 26 patients with radiologically confirmed EVA, 5 (19.2%) exhibited positional nystagmus compatible with BPPV through Dix-Hallpike and head-roll tests. Hearing loss usually accompanied BPPV attacks, and BPPV was recurrent in three patients. Multiple semicircular canals were frequently involved in each episode, and different canals were also involved in recurrent cases. Canalith repositioning procedures were usually successful without difficulty.

[Vestibular examination of children with alterations in balance (II): results by pathologies]

We review the findings of vestibular examinations in children according to disease. Just as in adults, the dizziness can be classified following a physiopathological scheme.

BMP/SMAD signaling regulates the cell behaviors that drive the initial dorsal-specific regional morphogenesis of the otocyst

During development of the otocyst, regional morphogenesis establishes a dorsal vestibular chamber and a ventral auditory chamber, which collectively constitute the membranous labyrinth of the inner ear. We identified the earliest morphogenetic event heralding the formation of the vestibular chamber, a rapid thinning and expansion of the dorsolateral wall of the otocyst, and showed that this process is generated by changes in otocyst cell shape from columnar to squamous, as opposed to changes in other cell behaviors, such as localized changes in cell proliferation or cell death. Moreover, we showed that thinning and expansion of the dorsolateral otocyst is regulated by BMP/SMAD signaling, which is both sufficient and necessary for localized thinning and expansion. Finally, we showed that BMP/SMAD signaling causes fragmentation of E-cadherin in the dorsolateral otocyst, occurring concomitantly with cell shape change, suggesting that BMP/SMAD signaling regulates cell-cell adhesion during the initial morphogenesis of the otocyst epithelium. Collectively, our results show that BMP signaling via SMADs regulates the cell behaviors that drive the initial dorsal-specific morphogenesis of the otocyst, providing new information about how regional morphogenesis of a complex organ rudiment, the developing membranous labyrinth, is initiated.

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.

Steroid treatment of hearing loss in enlarged vestibular aqueduct anomaly

OBJECTIVE

1. Determine whether corticosteroid therapy improves hearing thresholds of patients with enlarged vestibular aqueduct (EVA) anomaly. 2. Determine sample size for a future prospective study.

METHODS

Retrospective chart review hearing loss in EVA patients comparing patients treated with corticosteroids and untreated patients.

RESULTS

Eighty percent (n=5) of patients treated with steroids for hearing loss demonstrated audiometric improvement, compared to 14.3% of patients (n=7) not treated. The pure tone average improved by 17.7dB in the steroid treated group. A prospective, placebo-controlled trial would need between 19 and 45 patients in each group, treatment versus no-treatment, to achieve statistical significance.

CONCLUSION

Patients with EVA who develop hearing loss have a high rate of hearing improvement when treated with corticosteroid therapy. The hearing improvement appears to be better than spontaneous recovery.

Síndrome do aqueduto vestibular alargado: uma causa de disacusia neurossensorial

TEMA: a síndrome do aqueduto vestibular alargado (SAVA) é caracterizada pelo alargamento do aqueduto vestibular associada a disacusia. O grau da perda auditiva é variável, podendo ser flutuante, progressiva ou súbita. Sintomas vestibulares podem estar presentes. O diagnóstico é realizado por exames de imagem. OBJETIVO: relatar um caso de SAVA. MÉTODO: lactente, gênero feminino, realizou tomografia computadorizada de ouvidos e exames de audição. RESULTADO: constatou-se alargamento do aqueduto vestibular maior que 1,5mm de diâmetro e perda auditiva neurossensorial à direita. CONCLUSÃO: com a avaliação auditiva precoce é possível o diagnóstico da disacusia, mesmo em crianças com disacusias unilaterais. Embora a literatura consultada mostre que o diagnóstico da SAVA ocorra tardiamente, no presente caso, o diagnóstico etiológico foi possibilitado pela tomografia computadorizada.

Pediatric vestibulopathy and pseudovestibulopathy: differential diagnosis and management

PURPOSE OF REVIEW

Evaluation of children with vestibular complaints may be challenging. The approach to these patients is often quite different than the approach to adults with similar complaints. This review will discuss the evaluation of pediatric vestibular disease with an emphasis on recent evidence in the literature

RECENT FINDINGS

Recent evidence has elucidated the most common etiologies of vertigo in children, documented the utility and feasibility of objective diagnostic testing such as electronystagmography and vestibular evoked myogenic potentials in this population, and demonstrated the efficacy of new therapies such as rizatriptan for the treatment of migraine in children.

SUMMARY

An evidence-based approach to the evaluation of pediatric vestibular dysfunction may improve diagnostic yield and facilitate timely initiation of appropriate therapy.