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.

Audiologic and temporal bone imaging findings in patients with sensorineural hearing loss and GJB2 mutations.

OBJECTIVES/HYPOTHESIS: Our objectives were to determine genotype-phenotype correlations in patients with sensorineural hearing loss (SNHL) who undergo testing for GJB2 mutations and to examine the relationship of temporal bone anomalies seen on computed tomography (CT) and GJB2 mutations. STUDY DESIGN: We conducted a retrospective review of all children diagnosed with SNHL and who underwent GJB2 testing from 1997 to 2006. RESULTS: Of 840 patients, 146 (17.4%) had mutations. Seventy-six (9.1%) had biallelic GJB2 mutations and 70 (8.3%) had heterozygous mutations. When biallelic mutations were categorized as missense or nonsense mutations, the presence of at least one missense mutation was associated with mild or moderate SNHL. Biallelic nonsense mutations were associated with severe to profound SNHL. Among patients with GJB2 mutations, those with heterozygous mutations (n = 14 [20%]) had a higher rate of asymmetric SNHL loss than those with biallelic mutations (n = 6 [7.9%], P = .03). Those with heterozygous mutations were more likely to experience progression than were those with biallelic mutations, though this difference was only marginally significant (26.5% vs. 12.3%, respectively; P = .06). Patients who were wild type for GJB2 were more likely to have an enlarged vestibular aqueduct (EVA) than were those with biallelic and heterozygous mutations (29% vs. 11.9%, respectively; P = .004). Compared to patients who were wild type, those with biallelic mutations had a significantly lower rate of EVA. CONCLUSIONS: This is the largest single-institution study of pediatric patients with GJB2 mutations and SNHL. The functional consequences of GJB2 mutations correlated with the degree of hearing loss. Patients with M34T mutations and/or mild SNHL had a low risk of progression. Temporal bone anomalies were uncommon in patients with GJB2 mutations.

The large vestibular aqueduct: a new definition based on audiologic and computed tomography correlation.

OBJECTIVE: The study goal was to determine the prevalence and clinical significance of a large vestibular aqueduct (LVA) in children with sensorineural hearing loss (SNHL). STUDY DESIGN AND SETTING: We conducted a retrospective review of a pediatric SNHL database. One hundred seven children with SNHL were selected and their radiographic and audiometric studies were evaluated. Radiographic comparisons were made to a group of children without SNHL. RESULTS: A vestibular aqueduct (VA) larger than the 95th percentile of controls was present in 32% of children with SNHL. Progressive SNHL was more likely to occur in ears with an LVA and the rate of progressive hearing loss was greater than in ears without an LVA. The risk of progressive SNHL increased with increasing VA size as determined by logistic regression analysis. CONCLUSIONS: An LVA is defined as one that is >or=2 mm at the operculum and/or >or=1 mm at the midpoint in children with nonsyndromic SNHL. An LVA appears to be more common than previously reported in children with SNHL. A linear relationship is observed between VA width and progressive SNHL. SIGNIFICANCE: The finding of an LVA in children with SNHL provides diagnostic as well as prognostic information.

The influence of mutations in the SLC26A4 gene on the temporal bone in a population with enlarged vestibular aqueduct.

OBJECTIVE: To correlate genetic and audiometric findings with a detailed radiologic analysis of the temporal bone in patients with enlarged vestibular aqueduct (EVA) to ascertain the contribution of SLC26A4 gene mutations to this phenotype. DESIGN: A retrospective review of patients with EVA identified in a database of pediatric hearing-impaired patients. SETTING: A tertiary care pediatric referral center. PATIENTS: Seventy-one children with EVA and screening results for SLC26A4 mutations. MAIN OUTCOME MEASURES: Genetic screening results, audiometric thresholds, and radiographic temporal bone measurements. RESULTS: Seventy-one children with EVA were screened for SLC26A4 mutations. Mutations were found in 27% of children overall, while only 8% had biallelic mutations. The mean initial pure-tone average (PTA) was 59 dB; the mean final PTA was 67 dB. A bilateral EVA was found in 48 (67%) of the children; a unilateral EVA was found in 23 (33%). Progressive hearing loss (in at least 1 ear) was seen in 29 (41%) of the patients. The strongest genotype-phenotype interaction was seen in children with a bilateral EVA. Among children with SLC26A4 mutations, there was a significantly wider vestibular aqueduct at the midpoint and a wider vestibule width (P < .05) than in children without the mutation. Among patients with a bilateral EVA, children with any SLC26A4 mutation were more likely to have a more severe final PTA (64 dB vs 32 dB), larger midpoint measurement (2.1 vs 1.1 mm), and larger operculum measurement (3.0 vs 2.0 mm) than those without the mutation in their better-hearing ear (P < .05). CONCLUSIONS: In a population of pediatric patients with an EVA and hearing loss, SLC26A4 mutations are a contributor to the phenotype. Our data suggest that other genetic factors also have important contributions to this phenotype. The presence of an abnormal SLC26A4 allele, even in the heterozygous state, was associated with greater enlargement of the vestibular aqueduct, abnormal development of the vestibule, and possibly a stable hearing outcome.

Partial absence of the posterior semicircular canal in Alagille syndrome: CT findings.

We report a case of bilateral partial absence of the posterior semicircular canals (with normal lateral semicircular canals) imaged with CT in a patient with Alagille syndrome. Similar histologic findings have been reported in the pathology literature. This association has been previously reported only for Waardenburg syndrome in the imaging literature. We review the imaging findings and embryology of the semicircular canals, and suggest that this abnormality is specific to patients with Alagille or Waardenburg syndrome.

Audiometric, clinical and educational outcomes in a pediatric symptomatic congenital cytomegalovirus (CMV) population with sensorineural hearing loss.

OBJECTIVE: To correlate audiometric findings and outcomes with the clinical, radiological and educational findings in a symptomatic congenital cytomegalovirus (CMV) population with sensorineural hearing loss. METHODS: A retrospective review of data from 21 symptomatic congenital CMV patients identified in a pediatric hearing impaired database of 1500 patients. Clinical data, audiometric thresholds and outcomes, radiographic abnormalities, communication and educational achievements were used as outcome measures. RESULTS: Twenty-one patients were identified with symptomatic congenital CMV infection at birth; 5 with unilateral hearing loss and 16 with bilateral hearing loss. The median initial pure-tone average (PTA) for the 21 subjects was 86 dB and the median final PTA was 100 dB. Progression of hearing loss was seen in 9 patients (43%). Neurological and radiological sequelae of symptomatic CMV infection were seen in 81% of affected patients. Children with neurological dysfunction were significantly more likely to rely on special education (p = 0.045). There was a significant correlation between the severity of the initial PTA and the development of a progressive hearing loss (p = 0.0058). Initial hearing thresholds were significantly better in those children with a history of jaundice (p = 0.002), hepatosplenomegaly (HSM) (p = 0.022) and cerebral palsy (CP) (p = 0.013). There was a significant correlation between a less severe final PTA and the presence of CP (p = 0.005). A history of mental retardation in children was significantly associated with poorer communication skills (p = 0.043). CONCLUSIONS: The severity of neurological manifestations in congenital symptomatic CMV infection was positively correlated with the need for total and manual communication and the reliance on special education. Statistical associations between clinical findings such as hepatic dysfunction, CP and hearing level were identified however plausible mechanisms explaining these associations remain ambiguous and are discussed in the context of this complex population of children with congenital symptomatic CMV.

Development of an interactive model for teaching emergency pediatric radiography: preliminary report.

PURPOSE: The authors describe the development of an interactive digital teaching module designed to help prepare residents to diagnose emergency pediatric radiology cases. METHODS: Cases were identified using the authors' own dictation search software. Cases were selected that depicted common conditions that had been misdiagnosed by the radiology resident who had first interpreted them clinically. Normal cases involving similar anatomic regions were also collected. Images from these cases were captured from the picture archiving and communication system. "Hotspots" were superimposed on abnormalities to highlight them. Example dictations were captured. A simple user interface was developed for the teaching module, and a database was built to log all user responses. RESULTS: The system has been well received at the authors' institution. It has been incorporated into the standard orientation for all incoming residents. Residents' diagnostic performance has subjectively improved since the module was launched. CONCLUSIONS: The module is interactive, easy to use, and subjectively improves incoming residents' diagnostic accuracy. A prospective, controlled study assessing its impact on short-term and long-term diagnostic performance is under way.

The cochlear cleft.

BACKGROUND AND PURPOSE: Recent advances in the display of medical images permit the routine study of temporal bone CT images at high magnification. We noted an unfamiliar structure, which we now call the "cochlear cleft," in the otic capsule. To our knowledge, this report represents the first description of this structure in the medical imaging literature. METHODS: Temporal bone CT performed in 100 pediatric patients without sensorineural hearing loss were examined for the presence of cochlear clefts. Incidence of cochlear clefts as well as the relationship between age and incidence was examined. RESULTS: Cochlear clefts were present in 41% of the subjects. Incidence decreased with age. CONCLUSION: We describe a cleft in the otic capsule that is frequently seen on magnified images of temporal bone CT studies in children. The cleft may be the fissula ante fenestram.

Improving patient care: the use of a digital teaching file to enhance clinicians' access to the intellectual capital of interdepartmental conferences.

OBJECTIVE: We describe a simple method for creating teaching cases from clinical data, radiologic images, surgical images, and images from pathologic slides that are presented at tumor board conferences. CONCLUSION: The resulting interdisciplinary case files are of educational value both during and after conference presentations and can be used by clinicians to gather appropriate historical, laboratory, imaging, surgical, and pathologic data on their patients. This system improves the efficiency and accuracy in gathering patient histories when care is transferred among clinics, the emergency department, and wards.

Temporal bone abnormalities associated with hearing loss in Waardenburg syndrome.

OBJECTIVES/HYPOTHESIS: The objectives were to correlate audiometric thresholds with radiological findings and to determine the prevalence of inner ear radiological abnormalities in patients with hearing loss and Waardenburg syndrome. STUDY DESIGN: The study was a retrospective review of patients with Waardenburg syndrome identified in a pediatric hearing-impaired population and human genetics clinic. METHODS: Nine children with Waardenburg syndrome were identified. Eighty-nine children without sensorineural hearing loss served as control subjects. Clinical data, audiometric thresholds, and radiographic temporal bone measurements in these children were analyzed. RESULTS: Seven children were identified with hearing loss and Waardenburg syndrome. Four children had Waardenburg syndrome type 1, and three children had Waardenburg syndrome type 2. The overall prevalence of hearing loss in the total study population with Waardenburg syndrome was 78%. The mean pure-tone average was 99 dB. All of the children had sensorineural hearing loss. The hearing outcome was stable in 86% of the children. Twelve temporal bones were available for radiological analysis by computed tomography. Enlargement of the vestibular aqueduct was found in 50% of the CT scans. There was a significant difference in measurements of vestibular aqueduct width at the midpoint between the patients with Waardenburg syndrome and the control group (P <.05). There were also significant differences in the measurements of the vestibule (P =.0484), internal auditory canal (P =.0092), and modiolus (P =.0045) between the children with Waardenburg syndrome and the control group. CONCLUSION: A profound sensorineural hearing loss was characteristic of the study population with Waardenburg syndrome. Overall, 100% of patients with hearing loss and Waardenburg syndrome had temporal bone anomalies on at least one measurement of their inner ear, and 50% had an enlargement of the vestibular aqueduct at the midpoint. As shown by computed tomography, enlargement of the vestibular aqueduct and the upper vestibule, narrowing of the internal auditory canal porus, and hypoplasia of the modiolus are features of Waardenburg syndrome.

Enlarged vestibular aqueduct syndrome in the pediatric population.

OBJECTIVE: To correlate clinical and audiometric findings with the radiologic appearance in patients with enlarged vestibular aqueduct.DESIGN A retrospective review of data from enlarged vestibular aqueduct patients identified in a pediatric hearing-impaired database of 1,200 patients. SETTING A tertiary care pediatric referral center. PATIENTS: Subjects were included for study with a radiographic diagnosis of enlarged vestibular aqueducts in at least one ear by a pediatric neuroradiologist. MAIN OUTCOME MEASURES: Audiometric evaluations and radiographic temporal bone measurements. RESULTS: Seventy-seven patients were identified with an enlarged vestibular aqueduct with a male-to-female ratio of 1:1.5. Patients were followed for a mean of 34 months (range, 0-179 months). Hearing loss was bilateral in 87% of cases. Vestibular symptoms were present in only three (4%) of the patients. Three patients (4%) suffered a sudden decrease in hearing after mild head trauma. Borderline enlargement of the vestibular aqueduct was associated with varying degrees of sensorineural hearing loss. Ninety-seven percent (64 of 66) of ears in control subjects with no sensorineural hearing loss had normal vestibular aqueduct measurements at the midpoint and operculum. Overall, the audiogram remained stable in 51% of ears, fluctuated in 28%, and progressively worsened in 21%. Measurements of the vestibular aqueduct at the midpoint and the operculum did not correlate with the audiometric threshold or the audiogram configuration. However, mean vestibular aqueduct size at the operculum was significantly larger in those with a progressive loss when compared with those with a fluctuating or stable hearing outcome. CONCLUSIONS: Overall, audiometric thresholds remained generally stable, with sudden deterioration of hearing after head trauma seen in only three male patients. Progression of hearing loss after head trauma was not a significant finding in our patient population. Vestibular aqueduct opercular size alone showed a direct correlation with the audiometric outcome. Borderline enlarged vestibular aqueduct measurements appear to be associated with sensorineural hearing loss.