Chronological changes of hearing in pediatric patients with large vestibular aqueduct syndrome

Hearing loss trajectory and prediction model for children with enlarged vestibular aqueduct

PURPOSE

To explore how hearing changes over time and the characteristics associated with progressive hearing loss in children with enlarged vestibular aqueduct (EVA), and develop a prediction model for anticipation of hearing progression probability.

METHODS

A retrospective analysis was conducted on 48 children (92 ears) diagnosed with EVA. A total of 314 audiograms were included in the analysis of hearing loss trajectories using linear mixed-effects model. Progressive hearing loss was defined based on the difference between the initial and final hearing threshold. All participants had underwent one or two gene detection methods, including deafness gene screening and SLC26A4 whole coding exon sequencing.

RESULTS

The pure-tone thresholds (PTTs) at frequencies of 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz and the average are expected to increase by 0.34, 0.49, 0.54, 0.57, and 0.55 dB HL per each additional month. Age and genotypes have an interactive effect on PTT at frequencies of 500 Hz, 1000 Hz, and the average. The hazard ratio for the genotype without SLC26A4 c.919-2 A > G mutation was 4.91 (95 % confidence interval 1.76-13.7, P < 0.01). This prediction model fitted using age, initial average PTT, midpoint size of vestibular aqueduct, incomplete partition type II, and genotypes of SLC26A4 showed strong consistency and differentiation.

CONCLUSION

These findings reveal that the PTT would deteriorate over time in patients with EVA. The hearing threshold at high frequency and genotype without c.919-2 A > G heterozygous mutation deteriorated relatively fast. Genotype is an important predictive factor and the nomogram helps to predict progressive hearing loss.

Enlarged vestibular aqueduct as a cause of postneonatal deafness

INTRODUCTION

The enlarged vestibular aqueduct (EVA) is the most frequent malformation of the inner ear associated with sensorineural hearing loss (5-15%). It exists when the diameter in imaging tests is greater than 1.5 mm at its midpoint. The association between hearing loss and EVA has been described in a syndromic and non-syndromic manner. It can appear as a familial or isolated form and the audiological profile is highly variable. The gene responsible for sensorineural hearing loss associated with EVA is located in the same region described for Pendred syndrome, where the SCL26A4 gene is located.

OBJECTIVE

To describe a series of children diagnosed with EVA in order to study their clinical and audiological characteristics, as well as the associated genetic and vestibular alterations.

METHOD

Retrospective study of data collection of children diagnosed with EVA, from April 2014 to February 2023.

RESULTS

Of the 17 cases, 12 were male and 5 were female. 5 of them were unilateral and 12 bilateral. In 5 cases, a cranial traumatism triggered the hearing loss. Genetic alterations were detected in 3 cases: 2 mutations in the SCL26A4 gene and 1 mutation in the MCT1 gene. 13 patients (76.5%) were rehabilitated with hearing aids and 9 of them required cochlear implantation.

DISCUSSION

The clinical importance of AVD lies in the fact that it is a frequent finding in the context of postneonatal hearing loss. It is convenient to have a high suspicion to diagnose it with imaging tests, to monitor its evolution, and to rehabilitate early.

A New Methodology for Evaluation of Large Vestibular Aqueduct in CT and MRI Images

HYPOTHESIS

Development of a new method for large vestibular aqueduct (LVA)/large endolymphatic sac anomaly (LESA) assessment using magnetic resonance imaging (MRI) and computed tomography (CT)/cone beam CT (CBCT) images. The secondary objective was to compare both modalities.

BACKGROUND

The gold standard for LVA diagnosis is the analysis of CT images using Valvassori and Clemis or Cincinnati criteria. The previous studies showed inconclusive results regarding the correlation between audiological and radiological data.

METHODS

Retrospective analysis of radiological images from 173 patients (315 ears), who were diagnosed with LVA/LESA based on CT/CBCT and/or MRI images of the temporal bone. The images obtained using both techniques were used to measure the following dimensions of vestibular aqueduct (VA)/endolymphatic duct (ED)/intraosseous endolymphatic sac (ES): width of the opening, length, and width at external aperture. In MRI images, the maximal contact diameters of the extraosseous or intraosseous ES and dura mater were measured as well.

RESULTS

LVA has been reported to be bilateral in 82% (142 patients) and unilateral in 18% (31 patients) of cases. Comparison of MRI and CT/CBCT measurements showed a moderate correlation (0.64) in external aperture, a moderate correlation (0.57) in the width of the VA opening, and a weak correlation (0.34) in length measurements (p < 0.05).

CONCLUSION

We developed a new method to identify the heterogeneous pathology of LVA/LESA using reconstruction along the VA/ED/intraosseous ES axis, three measurements on two planes, and focus on the maximal contact diameter between the extraosseous or intraosseous ES and dura mater.

Fluid-solid coupling model and biological features of large vestibular aqueduct syndrome

Objective: Computed tomography (CT) images of the temporal bone of large vestibular aqueduct syndrome (LVAS) patients were used to establish 3D numerical models based on the structure of the inner ear, which are, in turn, used to construct inner ear fluid-solid coupling models. The physiological features and pathophysiology of LVAS were analyzed from a biomechanical perspective using finite element analysis. Methods: CT images of the temporal bone were collected from five children attending the Second Hospital of Dalian Medical University in 2022. The CT images were used to build 3D models of the inner ear containing the vestibular aqueduct (VA) by Mimics and Geomagic software, and round window membrane models and fluid-solid coupling models were built by ANSYS software to perform fluid-solid coupling analysis. Results: By applying different pressure loads, the deformation of the round window membranes occurred, and their trend was basically the same as that of the load. The deformation and stress of the round window membranes increased with the increase in load. Under the same load, the deformation and stress of the round window membranes increased with the expansion of the midpoint width of the VA. Conclusion: CT images of the temporal bone used clinically could establish a complete 3D numerical model of the inner ear containing VA. Fluctuations in cerebrospinal fluid pressure could affect inner ear pressure, and VA had a limiting effect on the pressure from cerebrospinal fluid. The larger the VA, the smaller the limiting effect on the pressure.

Vestibular Loss in Children Affected by LVAS and IP2 Malformation and Operated with Cochlear Implant

This is a single center cohort study regarding the prevalence of vestibular loss in hearing impaired children affected by large vestibular aqueduct syndrome (LVAS) with incomplete cochlear partition malformation type II (IP2), fitted with cochlear implant (CI). Twenty-seven children received CI operations at 0.4-13 years on one or both ears and tested for vestibular loss with head impulse test, video head impulse test, mini ice-water test and cervical VEMP. Vestibular loss was found in 19% of operated ears and in 13.9% of non-operated ears. The difference was not statistically significant and was not significantly modified by age at implantation, age at testing, sex, presence of SLC26A4 gene mutation or bilaterality. However, the presence of anatomic anomalies at the level of the vestibulum or semicircular canals was significantly associated with a higher incidence of vestibular loss in CI operated children but not in those non-operated. No other factors, such as the surgical access, the electrode type, the presence of Gusher perioperatively, or post-operative vertigo modified significantly the prevalence of vestibular loss. In conclusion, LVAS/IP2 appears to be the major determinant of vestibular loss in these children, with a less obvious impact of CI, excluding the cases with vestibulum/canal anomalies: this group might have a higher risk for vestibular loss after CI surgery.

Classifying the Large Vestibular Aqueduct: Morphometry to Audiometry

OBJECTIVE

Large vestibular aqueduct (LVA) is the most common inner ear dysplasia identified in patients with hearing loss. Our objective was to systematically quantify LVA morphologies and correlate imaging findings with established audiometric outcomes.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

Patients with large vestibular aqueduct identified radiographically, with or without hearing loss.

INTERVENTIONS

Diagnostic only.

MAIN OUTCOME MEASURES

Vestibular aqueduct (VA) width at midpoint, width at external aperture, and length were measured on cross-sectional imaging. Morphology was classified as type I (borderline), type II (tubular), or type III (funneled). Audiometric endpoints included air/bone conduction, pure tone averages, and air-bone gaps at 250 and 500 Hz. Statistical associations were evaluated using linear regression models, adjusted for age at first audiogram and sex.

RESULTS

One hundred seventeen patients (197 ears) were included, with mean age at first audiogram of 22.2 years (standard deviation, 21.7 yr). Imaging features associated with poor audiometric outcomes were increasing VA width at midpoint and external aperture, decreasing VA length, dilated extraosseous endolymphatic sac, cochleovestibular malformations, and increasing VA type (III > II > I).

CONCLUSIONS

Quantitative LVA measurements and a standardized morphologic classification system aid in prediction of early audiometric endpoints.

Cochlear Implantation in Children with Enlarged Vestibular Aqueduct: A Systematic Review of Surgical Implications and Outcomes

OBJECTIVES

This study investigated age at implantation, improvement in hearing and speech perception outcomes, as well as surgical complications in pediatric cochlear implant recipients with Pendred Syndrome (PS) or non-syndromic enlarged vestibular aqueduct (NSEVA).

DESIGN

A systematic review of the literature between 1984 and 2021 was performed. Two independent reviewers performed abstract and full-text screening using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The inclusion criteria were: English language, cochlear implant, age at implantation available, age <18 years, PS, Mondini malformation, and enlarged vestibular aqueduct. Full-text analysis was completed using the National Institute of Health assessment tool for case series and case-control studies. Studies were also graded according to the Oxford Centre for Evidence-Based Medicine grading system.

RESULTS

In total, 198 studies were identified and screened, and 55 studies were included for analysis. Audiological outcomes were available in 46 studies, and the four-frequency pure-tone audiogram average improved by 60 to 78 dB HL due to cochlear implantation. Auditory performance and speech intelligibility scores increased by 44%. The overall average implantation age was 60 months. The implantation age was 21 months lower in the studies where individuals were implanted after the year 2000 compared with those implanted before the year 2000. Perilymph gusher/oozing was the most common surgical incident reported, occurring in 187 of 1572 implantations.

CONCLUSIONS

In children with PS/NSEVA, cochlear implantation improves pure-tone average by 60 to 78 dB HL and capacity of auditory performance/speech intelligibility by 44%. The implantation age for these children has decreased during the last two decades but is still somewhat higher than reported for unselected pediatric cochlear implantation. Perilymph gusher/oozing is the most common surgical complication.

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.

[Correlation of temporal bone HRCT, SLC26A4 gene and hearing loss in enlarged vestibular aqueduct]

Objective:To explore the correlation between high-resolution computed tomography（HRCT） of temporal bones, SLC26A4 gene mutation and hearing loss in patients with enlarged vestibular aqueduct（EVA）. Methods:The medical records of 257 subjects hospitalized for moderate to severe sensorineural hearing loss in the Department of Otolaryngology Head and Neck Surgery, Hainan General Hospital between May 2018 to 2021 were retrospectively reviewed. All included cases received audiological examination, HRCT scanning of temporal bones and SLC26A4 gene sequencing. According to the Valvassori standard, cases with the diameter from the common peduncle of the semicircular canal to the midpoint of the outer orifice of the vestibular aqueduct（MP） over 1.5 mm, or the diameter of the outer orifice of the vestibular aqueduct（OP） more than 2.0 mm were diagnosed as EVA. There were 22 cases（44 ears） of EVA in the study, aged between 6 months to 17 years old. Based on the hearing changes at birth and during growth, 18 ears of which were classified into the stable hearing group, while the other 26 ears in the unstable group. Moreover, all involved cases were grouped by MP（1.5 to <3.0 mm and ≥3.0 mm） and OP（2.0 to <4.0 mm and ≥4.0 mm）. SPSS 25.0 software was applied in the study. The correlation between hearing loss and MP and OP was analyzed. The results of HRCT of temporal bones and SLC26A4 gene sequencing were compared as well. Results:Though the size of MP and OP was not statistically different between the stable and hearing groups in EVA ears（P>0.05）, it was significantly correlated with the severity of hearing loss（P<0.05）. Of the 22 EVA patients diagnosed by HRCT, 21 were positive for SLC26A4 gene mutation. The positive rate of EVA by SLC26A4 gene sequencing was highly consistent with HRCT（Kappa=0.975）. Conclusion:The size of MP and OP in EVA patients was related to the degree of hearing loss, but not to the stable nature of hearing loss. Temporal bone HRCT scanning and SLC26A4 gene sequencing are highly consistent in the diagnosis of EVA. The latter has no radiation and can be combined with hearing screening for early diagnosis of EVA.

A case of Landau-Kleffner syndrome with SLC26A4-related hearing impairment

Background

Landau-Kleffner syndrome (LKS) is an acquired aphasia and electroencephalogram (EEG) abnormalities mainly in temporoparietal areas. SLC26A4 mutations can cause hearing loss associated with enlarged vestibular aqueduct (EVA).

Case presentations

We report a case of LKS in a 5-year-old boy with non-syndromic EVA due to homozygous mutations of c.919-2A>G (IVS7-2A>G) in SLC26A4. He had normal language development before 2 years old. At the age of 2.5 years, he was admitted to the hospital due to remarkable language delay, and diagnosed with hearing loss with EVA. The seizures started at 4.4 years of age and EEG recording showed electrical status epilepticus during sleep (ESES) with a posterior-temporal predominance. He received cochlear implantation in the right ear at 4.7 years of age, which improved his hearing and language skills. The nocturnal focal motor seizures recurred at 4.9 years of age. Then a remarkable inability to respond to calls and reduction in spontaneous speech were noticed. He was treated with methylprednisolone at 5 years old, which controlled the seizures, suppressed ESES, and remarkably improved the language ability. The absence of seizures maintained until the last follow-up at 5.3 years of age, with further improvements in EEG recording and language ability.

Conclusions

The co-existence of LKS and hearing loss caused by SLC26A4 mutations increases the difficulty of LKS diagnosis, especially in the presence of hearing loss and impaired language skills. EEG discharges predominantly in temporoparietal areas, the occurrence of ESES, and language improvement after antiepileptic medications are potential indicators for LKS diagnosis.

Characteristics of electrically evoked auditory brainstem response in children with large vestibular aqueduct syndrome after cochlear implantation

BACKGROUND

The vestibular aqueduct (VA) width may affect the auditory conduction pathway of large vestibular aqueduct syndrome (LVAS) children.

OBJECTIVE

Analyzing the electrically evoked auditory brainstem response (EABR) after cochlear implantation (CI) in severe to profound sensorineural hearing loss (SNHL) children with LVAS.

MATERIALS AND METHODS

Fifty-four children with SNHL who received CI were selected, including 21 children with LVAS and 33 children without inner ear malformations (IEMs). The VA width was measured in LVAS children. The post-operative EABRs were recorded in all children.

RESULTS

For the LVAS group, the VA width was positively correlated with wave III (eIII) latency of EABR at the No. 2 electrode (E2), E5, E8, and E11, the VA width was positively correlated with wave V (eV) latency of EABR at E2, E5, E8, and E11. Only the eV latency of E2 showed a significant difference between the two groups.

CONCLUSION AND SIGNIFICANCE

SNHL children with LVAS and no IEMs have similar conduction of the auditory pathway. In the LVAS group, the conduction of the auditory pathway becomes better with the decrease of VA width. Rational use of post-operative EABRs and the measurement of anatomical parameters can effectively assess the development of part auditory pathways in LVAS children, which may be helpful in predicting post-operative speech and hearing recovery.

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.

Cochlear Implantation in Pediatric Patients With Enlarged Vestibular Aqueduct: A Systematic Review

OBJECTIVE(S)

To describe cochlear implantation (CI) outcomes, with speech perception, auditory, language, and parent-reported auditory and speech behaviors, in children with an enlarged vestibular aqueduct (EVA) and incomplete partition type 2 (IP-II) and compare to control children without inner ear malformations (IEMs) and to determine cerebrospinal fluid gusher rates and effect on outcomes.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

MEDLINE, Embase, Cochrane, and CINAHL databases were searched from inception to February 2020. Studies reporting relevant outcomes in children with EVA or EVA + IP-II and controls without IEMs undergoing CI were included. Mean differences in speech perception, auditory, and language scores between cases and controls were meta-analyzed. Gusher rates were determined by proportion meta-analyses.

RESULTS

Of 214 identified articles, 42 met inclusion criteria, evaluating 775 cases and 2,191 controls. Of -cases, 578 (74.6%) had EVA and 197 (25.4%) had EVA + IP-II. Cases showed a significant improvement in speech perception, auditory and language performance, comparable to controls. Parent-reported auditory and speech production behaviors outcomes were positive among cases and comparable to controls. Pooled gusher proportions in EVA and EVA + IP-II cases were 27.7% (95% CI: 17.6-39.1) and 48.6% (95% CI: 28.6-69.0), respectively, with a proportion difference of 20.9% (95% CI: 11.0-30.1). Gusher occurrence did not impact speech perception or language outcomes.

CONCLUSION

Outcomes in children with EVA or EVA + IP-II undergoing CI are favorable and largely comparable to outcomes in children with hearing loss undergoing CI without IEMs. Intraoperative gusher is more prevalent among children with EVA + IP-II as compared to iEVA. Gusher does not influence speech perception and language development outcomes.

LEVEL OF EVIDENCE

NA Laryngoscope, 2021.

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.

The Natural History of Hearing Loss in Pendred Syndrome and Non-Syndromic Enlarged Vestibular Aqueduct

INTRODUCTION

The aim was to investigate the progress of hearing loss over time in a cohort of pendred syndrome and non-syndromic enlarged vestibular aqueduct (PS/NSEVA) with one or two confirmed pathogenic variations in SLC26A4.

STUDY DESIGN

Retrospective cohort study.

SUBJECTS AND METHODS

At our tertiary referral center, a retrospective search of all patients with enlarged vestibular aqueduct, hearing loss and SLC26A4 mutations yielded 103 individuals by March 2017, 96 of whom had records of hearing levels; both an early audiometry and the latest between 3 and 668 months follow-up. Pure-tone average (PTA; average of thresholds at 0.5, 1, 2 and 4 kHz) was calculated for both ears at time 1 and time 2. Neonatal screening results were retrieved.

RESULTS

Eighty-seven (87) individuals had biallelic (M2) and 16 had monoallelic alterations (M1) in their SLC26A4. On average, the PTA progressed to 80 dB HL by the age of 6 years for the entire cohort, and 3.2 years for the biallelic (M2) affected individuals. 25% of the cohort was screened in the neonatal screening program; of these 42% had "passed" at least monaurally. Audiometric profiles related to age show faster deterioration in high frequencies than in low frequencies.

CONCLUSION

In patients with PS/NSEVA and SLC26A4 mutations, the average hearing loss progresses to 80 dB HL by the age of 6 years. For biallelic (M2) affected individuals it was 3.2 years. Although hearing levels reached severe to profound during childhood, almost 1/2 had passed neonatal hearing screening, at least monaurally, emphasizing the need for close follow-up.

Speech development after cochlear implantation in infants with isolated large vestibular aqueduct syndrome

Background: Few studies on speech performance of children after cochlear implantation (CI) described isolated large vestibular aqueduct syndrome (LVAS). Objective: To investigate speech developmental trajectories of infants with LVAS after CI, and to compare with those who have structurally normal inner ears. Materials and methods: 1112 infants with congenital severe to profound hearing loss participated in this study. 150 infants in group A were diagnosed with LVAS, 962 infants in group B with structurally normal inner ear. The speech performance was assessed via the Meaningful Use of Speech Scale (MUSS). The evaluations were performed pre-implant, 1, 3, 6, 9, 12, 24, 36, 48 and 60 months after CI. Results: The mean scores of the MUSS improved over a 5-year period after implantation in both groups A and B. The LVAS group presented similar speech developmental trajectory to the non-LVAS group at each assessment interval, except pre-operation. There were significant differences in mean scores between vocalizing behavior and oral communication skills, clarification skills of infants in both two groups. Conclusions and significance: Speech performance of infants with LVAS developed rapidly after CI and was similar to infants with structurally normal inner ear. For infants with isolated LVAS, CI had a significant effect and should be recommended as a therapeutic option.

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.

Sex-specific enlarged vestibular aqueduct morphology and audiometry

OBJECTIVE

Enlargement of the vestibular aqueduct (EVA) is one of the most common congenital malformations in pediatric patients presenting with sensorineural or mixed hearing loss. The relationship between vestibular aqueduct (VA) morphology and hearing loss across sex is not well characterized. This study assesses VA morphology and frequency-specific hearing thresholds with sex as the primary predictor of interest.

MATERIALS AND METHODS

A retrospective, longitudinal, and repeated-measures study was used. 47 patients at an academic tertiary care center with hearing loss and a record of CT scan of the internal auditory canal were candidates, and included upon meeting EVA criteria after confirmatory measurements of vestibular aqueduct midpoint and operculum widths. Audiometric measures included pure-tone average and frequency-specific thresholds.

RESULTS

Of the 47 patients (23 female and 24 male), 79 total ears were affected by EVA; the median age at diagnosis was 6.60 years. After comparing morphological measurements between sexes, ears from female patients were observed to have a greater average operculum width (3.25 vs. 2.70 mm for males, p = 0.006) and a greater average VA midpoint width (2.80 vs. 1.90 mm for males, p = 0.004). After adjusting for morphology, male patients' ears had pure-tone average thresholds 17.6 dB greater than female patients' ears (95% CI, 3.8 to 31.3 dB).

CONCLUSIONS

Though females seem to have greater enlargement of the vestibular aqueduct, this difference does not extend to hearing loss. Therefore, our results indicate that criteria for EVA diagnoses may benefit from re-evaluation. Further exploration into morphological and audiometric discrepancies across sex may help inform both clinician and patient expectations.

Hearing loss in unilateral and bilateral enlarged vestibular aqueduct syndrome

OBJECTIVE

To investigate any meaningful differences in hearing between patients with unilateral and bilateral enlarged vestibular aqueduct (EVA). EVA is a common radiological finding in children presenting with hearing loss. We hope to provide insight into the pathogenesis of EVA and provide further guidelines for unilateral EVA management. We hypothesized that hearing loss in unilateral EVA would be similar to that seen in bilateral EVA.

METHODS

A longitudinal retrospective study design was used. Three measures of hearing, pure tone average (PTA) word recognition score (WRS) and speech awareness threshold (SAT) and radiologic morphologies were tested for difference across unilateral versus bilateral ear EVA status. Linear mixed effects models were used to identify differences while accounting for time and multiple measurements per ear.

RESULTS

Using Cincinnati criteria, 89 ears fit inclusion criteria, 75 of which were from patients with bilateral EVA compared to 14 ears from patients with unilateral EVA. No significant differences across bilateral status were observed in audiological measurements. Models showed that speech recognition threshold (SRT) (p = 0.925), word recognition score (WRS)(p = 0.521) and pure tone average (PTA) of air and bone conduction from 250 to 4000 Hz (p = 0.281-0.933) were not statistically different with respect to bilateral status. Wilcoxon rank-sum tests showed no statistical difference in vestibular aqueduct width or operculum size (VA)(p = 0.234, p = 0.623). Each year after the first audiogram was associated with significantly greater SRT (p = 0.003) decreased WRS (0.014) and increased PTA (0.003.). Greater midpoint width was associated with significantly lower SRT (p = 0.004) WRS (<0.001) and PTA (<0.001.) CONCLUSION: Our results indicate no statistically significant difference in hearing ability with respect to bilateral EVA status, suggesting that unilateral EVA patients require close follow-up. Our results also demonstrate the progressive nature of EVA and a relationship between VA midpoint width and hearing loss severity.

Validation of the Chinese Sound Test: Auditory Performance of Hearing Aid Users

PURPOSE

The Chinese Sound Test (Hung, Lin, Tsai, & Lee, 2016) has been recently developed as a modified version of the Ling Six-Sound Test (Ling, 2012). By incorporating Chinese speech sounds, this test should be able to estimate whether the listener can hear across the Chinese speech spectrum. To establish the clinical validity of the test, this study examined the relationship between the aided audiometric thresholds and the distance thresholds.

METHOD

Sixty children with bilateral hearing aids were recruited. The aided sound-field thresholds at 250, 500, 1000, 2000, 4000, and 6000 Hz were compared with the distance thresholds of six sounds, /u, ə, a, i, tɕʰ, and s/, which encompass the entire Chinese speech frequency range from low to high.

RESULTS

Partial correlation and stepwise regression analyses revealed that the Chinese testing sounds are frequency specific and that the audibility of each sound could be predicted by a specific frequency threshold.

CONCLUSIONS

The results confirm the validity of the Chinese Sound Test, indicating that the testing sounds can be reliably used to assess the perception of frequency-specific information. Crucially, these data also demonstrate that the Chinese Sound Test is a useful tool to identify red flags of poor auditory access in daily environment to monitor device malfunctions and possible hearing fluctuations.

Vestibular Aqueduct Midpoint Width and Hearing Loss in Patients With an Enlarged Vestibular Aqueduct

Importance

Elucidating the relationship between vestibular aqueduct size and hearing loss progression may inform the prognosis and counseling of patients who have an enlarged vestibular aqueduct (EVA).

Objectives

To examine the association between vestibular aqueduct size and repeated measures of hearing loss.

Design, Setting, and Participants

For this retrospective medical record review, 52 patients with a diagnosis of hearing loss and radiologic diagnosis of EVA according to the Valvassori criterion were included. All available speech reception threshold and word recognition score data was retrieved; mixed-effects models were constructed where vestibular aqueduct size, age at diagnosis of hearing loss, and time since diagnosis of hearing loss were used to predict repeated measures of hearing ability. This study was performed at an academic tertiary care center.

Exposures

Variable vestibular aqueduct size, age at first audiogram, length of time after first audiogram.

Main Outcomes and Measures

Speech reception threshold (dB) and word recognition score (%) during routine audiogram.

Results

Overall, 52 patients were identified (29 females [56%] and 23 males [44%]; median age at all recorded audiograms, 7.8 years) with a total of 74 ears affected by EVA. Median (range) vestibular aqueduct size was 2.15 (1.5-5.9) mm, and a median (range) of 5 (1-18) tests were available for each patient. Each millimeter increase in vestibular aqueduct size above 1.5 mm was associated with an increase of 17.5 dB in speech reception threshold (95% CI, 7.2 to 27.9 dB) and a decrease of 21% in word recognition score (95% CI, -33.3 to -8.0 dB). For each extra year after a patient's first audiogram, there was an increase of 1.5 dB in speech recognition threshold (95% CI, 0.22 to 3.0 dB) and a decrease of 1.7% in word recognition score (95% CI, -3.08 to -0.22 dB).

Conclusions and Relevance

Hearing loss in patients with an EVA is likely influenced by vestibular aqueduct midpoint width. When considering hearing loss prognosis, vestibular aqueduct midpoint width may be useful for the clinician who counsels patients affected by EVA.

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.

Progressive Hearing Loss and Head Trauma in Enlarged Vestibular Aqueduct

Objective

Enlarged vestibular aqueduct is the most common radiographically identified cause of congenital sensorineural hearing loss and is frequently progressive. Imaging is often ordered during the workup of children with congenital sensorineural hearing loss in part to identify enlarged vestibular aqueduct given concern for progression with head trauma. However, this association has not been systematically evaluated. We aimed to determine the rate of progression and association with head trauma in individuals with enlarged vestibular aqueduct.

Data Sources

Systematic review of primary studies identified through PubMed, Embase, Cochrane, and Web of Science.

Review Methods

Meta-analysis was performed on patient-level data describing enlarged vestibular aqueduct, progressive sensorineural hearing loss, and head trauma extracted from articles identified on systematic review according to PRISMA guidelines.

Results

Twenty-three studies (1115 ears with enlarged vestibular aqueduct) met inclusion criteria. Progressive sensorineural hearing loss was found in 39.6% of ears, with trauma-associated progression in 12%. Limited case-control data show no difference in the incidence of progression between patients with and without head trauma.

Conclusions

Long-term progressive sensorineural hearing loss is common in enlarged vestibular aqueduct, but its association with head trauma is not strongly supported.

Enlarged vestibular aqueduct in congenital non-syndromic sensorineural hearing loss in egypt

To estimate the frequency of isolated enlarged vestibular aqueduct (EVA) in patients with non-syndromic sensorineural hearing loss (SNHL) in an Egyptian population sample and to correlate its size with the degree of hearing loss. The study group comprised 16 patients (32 ears) suffering from non-syndromic SNHL since childhood. After a complete basic audiological evaluation, all patients were submitted to non contrast CT scan of the petrous bone in both axial & coronal planes. Vestibular aqueduct (VA) was measured at two points (midpoint & operculum) on right & left sides. The study group was divided according to VA size into three groups: group A, B and C. Group A included 6 ears (4 patients) with EVA, group B included 11 ears (7 patients) with borderline EVA and group C included 15 ears (9 patients) with normal VA size. There were no statistically significant differences between the three groups as regards laterality, degree of hearing loss and audiometric configuration. There was no correlation between VA midpoint & operculum and different variables (age and average pure tone thresholds). However, a significant correlation between VA midpoint & operculum was found. EVA was diagnosed in 6 out of 32 ears (18.75%) in the study sample. EVA size was not related to the degree of hearing loss or configuration. Despite the insignificant findings, moderate and high frequency sloping SNHL were considered the most common findings seen in patients with EVA.

Timing of surgical intervention with cochlear implant in patients with large vestibular aqueduct syndrome

Objectives

(1) To report the speech perception and intelligibility results of Mandarin-speaking patients with large vestibular aqueduct syndrome (LVAS) after cochlear implantation (CI); (2) to compare their performance with a group of CI users without LVAS; (3) to understand the effects of age at implantation and duration of implant use on the CI outcomes. The obtained data may be used to guide decisions about CI candidacy and surgical timing.

Methods

Forty-two patients with LVAS participating in this study were divided into two groups: the early group received CI before 5 years of age and the late group after 5. Open-set speech perception tests (on Mandarin tones, words and sentences) were administered one year after implantation and at the most recent follow-up visit. Categories of auditory perception (CAP) and Speech Intelligibility Rating (SIR) scale scores were also obtained.

Results

The patients with LVAS with more than 5 years of implant use (18 cases) achieved a mean score higher than 80% on the most recent speech perception tests and reached the highest level on the CAP/SIR scales. The early group developed speech perception and intelligibility steadily over time, while the late group had a rapid improvement during the first year after implantation. The two groups, regardless of their age at implantation, reached a similar performance level at the most recent follow-up visit.

Conclusion

High levels of speech performance are reached after 5 years of implant use in patients with LVAS. These patients do not necessarily need to wait until their hearing thresholds are higher than 90 dB HL or PB word score lower than 40% to receive CI. They can do it “earlier” when their speech perception and/or speech intelligibility do not reach the performance level suggested in this study.

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.

The relationship between vestibular aqueduct diameter and sensorineural hearing loss is linear: a review and meta-analysis of large case series

INTRODUCTION

Inner ear homeostasis is dependent on the vestibular aqueduct and its content, the endolymphatic duct. Narrow and enlarged vestibular aqueducts have both been associated with hearing loss in Ménière's and large vestibular aqueduct syndromes. This review investigated the correlation between vestibular aqueduct diameter and pure tone average, and the effect of measurement site (i.e. the midpoint or the external aperture).

MATERIALS AND METHODS

A systematic review of the literature and meta-analysis of large case series published on the Allied and Complementary Medicine, British Nursing Index, Cumulative Index to Nursing and Allied Health, Embase, Health Business Elite, Health Management Information Consortium, Medline, PsycInfo and PubMed databases. References and personal books were also scrutinised.

RESULTS

A linear relationship between vestibular aqueduct diameter and hearing loss was observed, with a projected increase of 6 dBHL per unit of vestibular aqueduct diameter (95 per cent confidence interval, 2-10; p = 0.003). This relationship was independent of measurement site.

DISCUSSION

This dose-dependent or linear relationship supports the role of flow and/or pressure change as aetiological factors in the pathogenesis of hearing loss, as per Poiseuille's law. This aetiological association is strengthened by the fact that the observed relationship is independent of measurement site.

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

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

Eighty-three individuals, 11 months to 59 years of age, with EVA in at least one ear were studied. 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 were examined.

RESULTS

Linear mixed-effects model indicated significantly poorer hearing in ears with EVA in 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.

[Large endolymphatic duct and sac syndrome (LEDS) : part I: analysis of imaging findings]

OBJECTIVE

Large endolymphatic duct and sac (LEDS) syndrome is the most common radiologically detectable form of inner ear malformation (IEM) associated with sensorineural hearing loss (SNHL). Nevertheless, it is relatively unknown in the German-speaking countries.

METHODS

Among all patients referred from ear, nose, and throat specialists to the radiology department with clinically suspected IEM between 1994 and 2003, we identified the cases of LEDS. The retrospective study included clinical records, high-resolution computed tomography, and magnetic resonance imaging.

RESULTS

Of 169 patients, 17 (median age 12 years; 12 females) showed LEDS. A total of 28 ears were affected. Ten patients (6%; 15 ears) had isolated LEDS, while seven patients showed additional IEM (4%; 13 ears). The most frequent of these was dysplastic vestibule (13/13 ears), followed by Mondini deformity (10/13 ears) and dilated semicircular canals (7/13 ears). Three of 13 ears revealed severe IEM of the cochlea, vestibule, and semicircular canals. No correlation could be demonstrated between the severity of morphological changes and the degree of SNHL.

CONCLUSION

LEDS may be an underestimated cause of SNHL. Imaging is necessary for a confident diagnosis.

[Large endolymphatic duct and sac syndrome : part 2: clinical manifestations]

OBJECTIVE

The aim of this study was to clarify the clinical course of large endolymphatic duct and sac syndrome (LEDS). Although LEDS is the most common form of radiologically detectable inner ear malformation associated with sensorineural hearing loss (SNHL), it is relatively unknown in the German-speaking countries. We hoped to derive useful pointers for clinical care.

METHODS

We evaluated the clinical audiometric records and imaging findings of 169 patients with clinically suspected inner ear malformation seen between 1994 and 2003. Following identification of all LEDS cases, we serially investigated the anamnestic and functional data with regard to severity and course.

RESULTS

Among 169 patients, 17 (median age 12 years; 12 females) showed LEDS. A total of 28 ears were affected. Clinically, most cases were of prelingual or perilingual onset and displayed steady or fluctuatingly progressive severe SNHL with emphasis on the high frequencies or deafness. Episodes of sudden hearing loss were relatively frequent. No correlation could be demonstrated between the severity of morphological changes and the degree of SNHL.

CONCLUSION

Progression of SNHL and episodes of sudden hearing loss were seen mainly in late childhood or adolescence. This should be taken into account when informing and advising patients and planning therapy.

Analysis of the SLC26A4 gene in patients with Pendred syndrome in Taiwan

Pendred syndrome (PS) is an autosomal recessive disease that is characterized by congenital sensorineural hearing loss, goiter, and a partial iodine organification defect. In this study, we characterized the thyroid status and identified mutations in the SLC26A4 gene in Chinese subjects with PS. We evaluated 7 unrelated Chinese subjects who had PS. Biochemical analysis, formal audiogram, ultrasonography of the thyroid gland, perchlorate discharge test, computerized tomography scan of the vestibular aqueducts, and DNA sequence analysis of SLC26A4 were performed. Levels of thyroid hormones were essentially normal in all patients: 2 patients had goiters and/or elevated serum thyroglobulin levels, whereas 2 other patients had positive thyroid antibodies and a positive perchlorate discharge test. We identified SLC26A4 gene mutations in 6 of 7 probands and their affected relatives. The affected subjects in family I was compound heterozygous for 2 missense mutations: a mutation in exon 9 (1079C>T) that resulted in the replacement of alanine by valine at codon 360 (A360V) and a mutation in exon 19 (2168A>G) that resulted in the replacement of histidine by arginine at codon 723 (H723R). The affected subjects in families II and III all were homozygous for a mutation in intron 7. The probands IV and V were compound heterozygotes for the mutation in intron 7 and in exon 19, and the proband VI was compound heterozygous for the intron 7 mutation and a missense mutation in exon 12 (1343C>T) that resulted in the replacement of serine by leucine at codon 448 (S448L). One novel mutation was identified (A360V). We identified biallelic mutations in the SLC26A4 gene in 6 of 7 probands with PS in Taiwan, including a novel missense mutation. The mild thyroid dysfunction in these patients suggests that PS should be considered in all patients with congenital or early-onset hearing impairment.

Anomalies of the Middle and Inner Ear

The development of the middle and inner ear highlights the intricacy of embryology. As early as 3 weeks after fertilization, the inner ear begins taking form. This process, along with development of the middle ear, continues throughout gestation. At birth, the middle ear, inner ear, and associated structures are almost adult size. An understanding of the embryologic development of the ear serves as a foundation for evaluating and managing congenital malformations of these structures. The focus of this article is the normal, abnormal, and arrested development of the middle and inner ear, with a clinical emphasis on malformed middle and inner ear structures and a discussion of associated syndromes.

Morphological analysis of the vestibular aqueduct by computerized tomography images

OBJECTIVE

In the last two decades, advances in the computerized tomography (CT) field revise the internal and medium ear evaluation. Therefore, the aim of this study is to analyze the morphology and morphometric aspects of the vestibular aqueduct on the basis of computerized tomography images (CTI).

MATERIAL AND METHOD

Computerized tomography images of vestibular aqueducts were acquired from patients (n=110) with an age range of 1-92 years. Thereafter, from the vestibular aqueducts images a morphometric analysis was performed. Through a computerized image processing system, the vestibular aqueduct measurements comprised of its area, external opening, length and the distance from the vestibular aqueduct to the internal acoustic meatus.

RESULTS

The morphology of the vestibular aqueduct may be funnel-shaped, filiform or tubular and the respective proportions were found to be at 44%, 33% and 22% in children and 21.7%, 53.3% and 25% in adults. The morphometric data showed to be of 4.86 mm(2) of area, 2.24 mm of the external opening, 4.73 mm of length and 11.88 mm of the distance from the vestibular aqueduct to the internal acoustic meatus, in children, and in adults it was of 4.93 mm(2), 2.09 mm, 4.44 mm, and 11.35 mm, respectively.

CONCLUSIONS

Computerized tomography showed that the vestibular aqueduct presents high morphological variability. The morphometric analysis showed that the differences found between groups of children and adults or between groups of both genders were not statistically significant.

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

OBJECTIVE

To describe the long-term audiologic findings in pediatric patients with enlarged vestibular aqueducts (EVAs). The relationship between the hearing loss (HL) and the dimensions of the EVA, enlarged endolymphatic duct (EED), or enlarged endolymphatic sac (EES) was also investigated. The influence of a Pendred syndrome (PS) diagnosis on the audiologic phenotype was also examined.

STUDY DESIGN

Retrospective analysis of case notes and imaging records, including measurement of the dimensions of the EVA, EED, and EES.

SETTING

Tertiary referral center.

PATIENTS

Twenty-seven patients (21 female, 6 male) had an EVA in at least one ear. Eighty-five percent had bilateral enlargements. Median age at onset of follow-up was 5.0 years, and median follow-up was 9.7 years.

MAIN OUTCOME MEASURES

Hearing thresholds at the start and end of follow-up, rate of progression of HL, history of sudden drops in hearing.

RESULTS

: All ears with an EVA had HL. Average HL at the start and end of follow-up was severe. Thirty-seven percent of patients had progressive HL, and 33% reported sudden drops in hearing. Progression was significantly associated with a history of sudden drops. PS patients had worse hearing at the end of follow-up as compared with nonsyndromic patients. There was no evidence of a relationship between the dimensions of the EVA, EED, or EES and the severity or progression of HL.

CONCLUSIONS

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.

Role of 3D CT in the Evaluation of the Temporal Bone

In recent years, three-dimensional (3D) multiplanar reformatted images from conventional cross-sectional computed tomographic (CT) data have been increasingly used to better demonstrate the anatomy and pathologic conditions of various organ systems. Three-dimensional volume-rendered (VR) CT images can aid in understanding the temporal bone, a region of complex anatomy containing multiple small structures within a relatively compact area, which makes evaluation of this region difficult. These images can be rotated in space and dissected in any plane, allowing assessment of the morphologic features of individual structures, including the small ossicles of the middle ear and the intricate components of the inner ear. The use of submillimeter two-dimensional reconstruction from CT data in addition to 3D reformation allows depiction of microanatomic structures such as the osseous spiral lamina and hamulus. Furthermore, 3D VR CT images can be used to evaluate various conditions of the temporal bone, including congenital malformations, vascular anomalies, inflammatory or neoplastic conditions, and trauma. The additional information provided by 3D reformatted images allows a better understanding of temporal bone anatomy and improves the ability to evaluate related disease, thereby helping to optimize surgical planning.

The large vestibular aqueduct--case report and review of the literature

Patients with a large vestibular aqueduct (LVA) suffer from a loss of hearing in childhood at an early onset. An acute loss of hearing can be precipitated by minor head trauma. Until now there seems to be no sufficient therapy for stopping the progression of a loss of hearing. It has been shown that a cochlear implantation is a worthwhile procedure if the patient is almost deaf. We report the case of a patient with a bilateral LVA. A loss of hearing was confirmed at the age of 16 months. Exposure to loud noise triggered an acute progression of the hearing loss. At the age of 18 years, LVA was confirmed radiologically, revealing an enlarged endolymphatic duct and sac in MRI scans and an enlarged vestibular aqueduct in the CT scan. We successfully performed a cochlear implant (MED-EL, Combi 40+ flex). Proceeding from this case report, the paper reviews the literature on LVA.