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The aim of this study was to determine and classify inner ear abnormalities in patients who had cochlear implants because of congenital sensorineural hearing loss using preoperative temporal bone computed tomography and magnetic resonance imaging. Patients in the otolaryngology department who had cochlear implants because of congenital sensorineural hearing loss between January 2011 and December 2013 were included in the study. There were 167 male and 133 female patients, a total of 300. All of the patients were evaluated with 4-detector-row computed tomography and 1.5 Tesla magnetic resonance imaging. Inner ear abnormalities were found in 136 of 600 ears (20.3%). There were six ears with incomplete partition-II (4.4%), five ears with incomplete partition-I (3.6%), two ears with Michel deformity (1.4%), two ears with cochlear hypoplasia (1.4%), two ears with cochlear otosclerosis (1.4%), and one ear with common cavity deformity (0.7%). Dilatation of the internal acoustic canal was found in 42 ears (30.9%); also, 21 ears with cochlear nerve aplasia/hypoplasia (15.4%), 5 ears with internal acoustic canal aplasia, and 1 ear with internal acoustic canal hypoplasia (0.73%) were detected. There were 10 ears with posterior semicircular canal (7.3%), 10 ears with lateral semicircular canal (7.4%), 8 ears with superior semicircular canal aplasia/hypoplasia (5.9%), and 8 ears with lateral semicircular canal-vestibular dysplasia. An enlarged vestibular aqueduct was found in 16 ears (11.7%). High jugular bulbs were found in 21 ears; however, this variation was not considered to be an inner ear abnormality. Computed tomography and magnetic resonance imaging are essential for the evaluation, determination, and classification of inner ear abnormalities in patients with congenital sensorineural hearing loss who are candidates for cochlear implant operations. Also, these radiological instruments aid in determining contraindications and predicting intraoperative difficulties. Computed tomography and magnetic resonance imaging findings for these patients should be evaluated by an experienced radiologist before the operation.

Objectives: The aim of this study was to assess the outcomes of cochlear implantation in children with inner ear malformations (IEMs). Methods: A retrospective review of 212 children who received implants from September 1994 to May 2004 was performed. Forty-six of them had radiologic evidence of IEMs. The preoperative evaluations, intraoperative findings, postoperative complications, and performance outcomes were analyzed. For the comparative analysis of performance outcomes, the children with IEMs were matched and compared with children with a normal inner ear who had received implants. Statistical analysis was performed with a repeated-measures analysis of variance. Results: All of the children were studied with computed tomography and magnetic resonance imaging. Three-dimensional volume rendering of magnetic resonance images was performed in cases that were difficult to interpret because of structural complexity. The operative findings included aberrant facial nerves in 2 children and cerebrospinal fluid gushers in 22 children. Intraoperative fluoroscopic examination was performed to evaluate electrode placement. There were no serious postoperative complications. All children with IEMs achieved open-set speech perception abilities, except for the children with a narrow internal auditory canal (IAC), and showed progressive improvement of their speech perception abilities over time. There were no statistically significant differences in performance measured by the Common Phrases test between the 2 groups. Although the repeated-measures analysis of variance indicated that children with IEMs performed more poorly than those with a normal inner ear on the Phonetically Balanced Kindergarten test for phonemes, statistical significance was not found at 2 years after implantation. The children with a narrow IAC benefited from the implantation and used the device every day, although their speech perception abilities were limited. Conclusions: The results of the present study show that cochlear implantation can be performed relatively safely in deaf children with IEMs and that they receive considerable benefit from their implants. Substantial benefit can be expected from implantation in children with most kinds of IEMs, except for a narrow IAC, which is often associated with limited results.

Estimation of cochlear length is gaining attention in the field of cochlear implants (CIs), mainly for selecting of CI electrode lengths. The currently available tools to estimate the cochlear duct length (CDL) are only valid for normal inner anatomy. However, inner ear malformation (IEM) types are associated with different degrees of cystic apices, limiting the application of CDL equations of normal anatomy inner ear. Therefore, this study aimed to understand the degree to which the outer wall (OW) is observed in different malformation types and to formulate mathematical equations to estimate the OW length (OWL) from cochlear parameters, namely the basal turn diameter (A-value) and width (B-value). Three-dimensional (3D) segmentation of promontory and fluid parts of the inner ear was performed to understand the extent to which the OW is visible to measure the OWL manually. Enlarged vestibular aqueduct syndrome (EVAS) was diagnosed in 37 ears, which consistently showed the extent of the OW to an angular depth of 540°, beyond which the cystic apex starts. Incomplete partition (IP) type I was observed in 30 ears, with the OW extending to only 360° of angular depth. IP type II was observed in 35 ears, with the OW extending to 450° of angular depth. IP type III was identified in 24 ears, with the OW observed for 540° of angular depth. Cavity-type malformations were observed in 36 ears, and circumference was measured in the axial view. A strong positive linear correlation was observed between the manually measured OWL and cochlear parameters for all malformation types analyzed. A multiple linear regression model was applied to formulate mathematical equations, which was further used to create a software application for estimating OWLs in IEM types, using cochlear parameters as inputs.

During the follow-up of recurrent pneumonia in a 9-month-old girl, rhinorrhea with discharge of a positional and intermittent nature was discovered. Radiological assessment was requested to detect any skull base openings and cerebrospinal fluid (CSF) leakage. T2-weighted MR cisternography showed bilateral inner ear dysplasia, communication of the internal auditory canal with the vestibule, and effusion in the right middle ear. Intrathecal contrast-enhanced MR cisternography revealed a CSF fistula from the right internal auditory canal to the Eustachian tube. The patient was operated upon on the right side, and the presence of a CSF leak near the oval window was confirmed. No adverse effects were seen during the short-term and long-term follow-up. Diagnosing this case required special attention, careful examination, and relevant investigations to find the site of CSF leakage in this patient with bilateral inner ear dysplasia.

Identification of the inner ear malformation types from radiographs is a complex process. We hypothesize that each inner ear anatomical type has a uniqueness in its appearance in radiographs. The outer contour of the inner ear was captured from the mid-modiolar section, perpendicular to the oblique-coronal plane, from which the A-value was determined from CT scans with different inner ear anatomical types. The mean A-value of normal anatomy (NA) and enlarged vestibular aqueduct syndrome (EVAS) anatomical types was greater than for Incomplete Partition (IP) type I, II, III and cochlear hypoplasia. The outer contour of the cochlear portion within the mid-modiolar section of NA and EVAS resembles the side view of Aladdin’s lamp; IP type I resembles the side-view of the Sphinx pyramid and type II a Pomeranian dog’s face. The steep spiraling cochlear turns of IP type III resemble an Auger screw tip. Drawing a line parallel to the posterior margin of internal auditory canal (IAC) in axial-view, bisecting the cavity into cochlear and vestibular portions, identifies common-cavity; whereas a cavity that falls under the straight-line leaving no cochlear portion identifies cochlear aplasia. An atlas of the outer contour of seventy-eight inner ears was created for the identification of the inner malformation types precisely.

Sensory hair cells and their associated non-sensory supporting cells in the inner ear are fundamental for hearing and balance. They arise from a common progenitor 1 , but little is known about the molecular events specifying this cell lineage. We recently identified two allelic mouse mutants, light coat and circling ( Lcc ) and yellow submarine ( Ysb ), that show hearing and balance impairment 2 . Lcc / Lcc mice are completely deaf, whereas Ysb / Ysb mice are severely hearing impaired 2 . We report here that inner ears of Lcc / Lcc mice fail to establish a prosensory domain and neither hair cells nor supporting cells differentiate, resulting in a severe inner ear malformation, whereas the sensory epithelium of Ysb / Ysb mice shows abnormal development with disorganized and fewer hair cells. These phenotypes are due to the absence (in Lcc mutants) or reduced expression (in Ysb mutants) of the transcription factor SOX2, specifically within the developing inner ear. SOX2 continues to be expressed in the inner ears of mice lacking Math1 (also known as Atoh1 and HATH1 ), a gene essential for hair cell differentiation, whereas Math1 expression is absent in Lcc mutants, suggesting that Sox2 acts upstream of Math1 .

Objective Identify the prevalence of syndromes in a cohort of patients who underwent cochlear implantation, to report on the presence of inner and middle ear malformations and highlight the surgical difficulties encountered. Study design Observational, retrospective study. Setting Tertiary referral children’s hospital pediatric cochlear implant program. Material & methods An IRB-approved retrospective chart review of children undergoing cochlear implantation at a tertiary academic medical center, from 2018 to 2023. Preoperative imaging data of syndromic patients in that cohort with special attention to the presence of inner ear or middle ear malformations were collected. Abnormal intraoperative findings and difficulties reported by the surgeons were also noted. Results 1024 children were unilaterally implanted for bilateral profound hearing loss. There were 45 cases diagnosed with associated syndromes (4.3%). The commonest syndromes were Jervell and Lange Nielsen (JLN) syndrome followed by Waardenberg syndrome (WS), in a prevalence of 34% and 32% respectively. These syndromes had no associated inner ear malformations (IEM). Less common syndromes included Branchio-oto-renal (BOR) syndrome, CHARGE association and Treacher Collins syndrome, 3 cases each, and keratosis icthyosis deafness syndrome (KID), Usher syndrome and Albino, 2 cases each and an H syndrome case. There were 9 cases (20%) with IEM, with 6 cases of perilymph gusher. Two cases had middle ear anomalies and one case had a facial nerve course abnormality. The outcome of these cases was similar to non-syndromic cases. Conclusion Children with syndromic HL should be dealt with on a case by case scenario to diagnose inner and middle ear malformations. Additional disabilities can affect the rehabilitation procedures. All children with congenital hearing loss should undergo pediatric, cardiologic, ophthalmologic and nephrologic examination in order to exclude the syndromic etiology of hearing loss.

Purpose We reviewed the genotypes and the imaging appearances of cochleae in CHARGE patients from two large tertiary centres and analysed the observed cochlear anomalies, providing detailed anatomical description and a grading system. The goal was to gain insight into the spectrum of cochlear anomalies in CHARGE syndrome, and thus, in the role of the CHD7 gene in otic vesicle development. Methods We retrospectively reviewed CT and/or MR imaging of CHARGE patients referred to our institutions between 2005 and 2022. Cochlear morphology was analysed and, when abnormal, divided into 3 groups in order of progressive severity. Other radiological findings in the temporal bone were also recorded. Comparison with the existing classification system of cochlear malformation was also attempted. Results Cochlear morphology in our CHARGE cohort ranged from normal to extreme hypoplasia. The most common phenotype was cochlear hypoplasia in which the basal turn was relatively preserved, and the upper turns were underdeveloped. All patients in the cohort had absent or markedly hypoplastic semicircular canals and small, misshapen vestibules. Aside from a stenotic cochlear aperture (fossette) being associated with a hypoplastic or absent cochlear nerve, there was no consistent relationship between cochlear nerve status (normal, hypoplasia, or aplasia) and cochlear morphology. Conclusion Cochlear morphology in CHARGE syndrome is variable. Whenever the cochlea was abnormal, it was almost invariably hypoplastic. This may shed light on the role of CHD7 in cochlear development. Accurate morphological description of the cochlea contributes to proper clinical diagnosis and is important for planning surgical treatment options.

Purpose A narrow bony internal auditory canal (IAC) may be associated with a hypoplastic cochlear nerve and poorer hearing performances after cochlear implantation. However, definitions for a narrow IAC vary widely and commonly, qualitative grading or two-dimensional measures are used to characterize a narrow IAC. We aimed to refine the definition of a narrow IAC by determining IAC volume in both control patients and patients with inner ear malformations (IEMs). Methods In this multicentric study, we included high-resolution CT (HRCT) scans of 128 temporal bones (85 with IEMs: cochlear aplasia, n  = 11; common cavity, n  = 2; cochlear hypoplasia type, n  = 19; incomplete partition type I/III, n  = 8/8; Mondini malformation, n  = 16; enlarged vestibular aqueduct syndrome, n  = 19; 45 controls). The IAC diameter was measured in the axial plane and the IAC volume was measured by semi-automatic segmentation and three-dimensional reconstruction. Results In controls, the mean IAC diameter was 5.5 mm (SD 1.1 mm) and the mean IAC volume was 175.3 mm 3 (SD 52.6 mm 3 ). Statistically significant differences in IAC volumes were found in cochlear aplasia (68.3 mm 3 , p  < 0.0001), IPI (107.4 mm 3 , p  = 0.04), and IPIII (277.5 mm 3 , p  = 0.0004 mm 3 ). Inter-rater reliability was higher in IAC volume than in IAC diameter (intraclass correlation coefficient 0.92 vs. 0.77). Conclusions Volumetric measurement of IAC in cases of IEMs reduces measurement variability and may add to classifying IEMs. Since a hypoplastic IAC can be associated with a hypoplastic cochlear nerve and sensorineural hearing loss, radiologic assessment of the IAC is crucial in patients with severe sensorineural hearing loss undergoing cochlear implantation.

Objectives Inner ear malformations (IEMs) may result in differences in outcomes of cochlear implant user. These differences could be observed in both behavioral and objective tests. eCAP is the most common used objective test in cochlear implants and have different presence rate in cochlear implant users with and without IEMs. This study aims to evaluate eCAP results from CI user with and without IEMs through different recoding methods; amplitude growth function, spreads of excitation and refractory recovery. Methods There were 42 CI users (20 IEM&22 normal) above five-years old and with at least one year experience. Three different eCAP measurement was conducted at several intracochlear electrodes. Presence rate, threshold levels and amplitude were compared between groups. Results For Amplitude growth function measurement, when the percentage of detected eCAP thresholds was analyzed between groups, there was a significant difference only for basal electrode and no significant difference for apical and middle electrodes. Similarly, the presence rate of RecF-eCAP for both groups were in a downward trend from apical to basal. However, there was no significant difference in AGF-eCAP and RecF-eCAP amplitudes between groups for the cochlea’s apical, middle and basal region. Although the presence rate of SOE-eCAP was lower for IEM group, there was no significant difference in ECAP amplitudes for all maskers. Conclusions It could be inferred that even though the observable eCAP rate differed between these two groups when the observable eCAP was recorded, the IEM group produced eCAP with similar amplitudes to normal cochlea group.