This study aimed to investigate auditory brainstem response (ABR) findings across subgroups of inner ear anomalies and to compare the ABR profiles in cases with cochlear nerve deficiency (CND). A total of 189 ears from 109 individuals with various inner ear anomalies were evaluated. Radiological findings were used to classify each ear into specific anomaly subgroups and to assess cochlear nerve status. ABR outcomes were then analyzed accordingly. CND was consistently observed in complete labyrinthine aplasia, rudimentary otocyst, cochlear aplasia, and common cavity malformations, with absent ABR wave V and cochlear microphonic (CM) responses. Cochlear hypoplasia and incomplete partition subtypes showed variable ABR and CM responses. In cochlear aperture anomalies, CND was consistently observed, with absent wave V but detectable CM of variable latency. Wave V responses differed significantly between normal and CND ears (p < 0.001), whereas CM responses did not (p = 0.055). This study delineates ABR characteristics specific to inner ear anomaly subgroups and highlights the influence of CND on ABR outcomes. The findings underscore the potential of detailed ABR analysis to serve as a valuable tool for guiding auditory rehabilitation decisions and emphasize its relevance in shaping future clinical practice guidelines.

To examine the histopathologic features of inner ear malformations (IEMs) and their implications for cochlear implant (CI) surgery, focusing on neural tissue preservation and electrode selection. Retrospective histopathologic case series analysis. Tertiary academic center. Twenty-three temporal bones (ears) with IEMs were identified, from which 7 representative cases (some bilateral, some unilateral), including 2 incomplete partition type I (IP-I), 1 IP-II, 1 IP-III, and 3 cochlear hypoplasia cases are described in detail. None. Microscopic assessment of cochlear structures relevant to CI surgery, including modiolar development, neural tissue presence and location, spiral ganglion cell distribution, and interscalar septum integrity. Neural tissue was present in malformed cochleae despite the absence of bony structures in several cases. IP-I specimens demonstrated spiral ganglion cells predominantly in the internal auditory canal fundus. IP-II and IP-III cases showed unprotected neural tissue in the cochlear center. Cochlear hypoplasia cases exhibited variable neural development, ranging from well-developed to hypoplastic cochlear nerves and reduced spiral ganglion cells. Histopathologic findings suggest that lateral wall electrodes may be preferable for many IEM cases to avoid damage to unprotected neural tissue. Electrode selection should be individualized based on the type of malformation, particularly considering compressed or shortened arrays in cases of cochlear hypoplasia. Neural tissue preservation despite bony malformation supports the potential for successful CI outcomes in IEM cases when appropriate surgical techniques and electrode choices are employed.

The vestibular aqueduct (VA) is a bony channel that houses the endolymphatic duct, linking the inner ear to the endolymphatic sac located in the posterior cranial fossa. The VA plays a crucial role in the metabolism and pressure buffer of the inner ear, and its enlargement can result in hearing impairment and balance disorders. The human VA often shows anatomical variations and even imaging can be difficult to appreciate, so clinicians need more data on the normal anatomy of VA for better understanding of radiological evaluation of enlarged VA. Enlarged vestibular adequate syndrome (EVAS) is reported to be one of the commonest anomalies of the inner ear associated with sensorineural hearing loss, although the exact mechanism of such loss is unclear. The EVAS can cause progressive sensorineural hearing loss (SNHL), in addition to sudden SNHL, conductive hearing loss, and mixed hearing loss. Mutations in a gene called SLC26A4 (formerly known as the PDS gene) are the primary cause of EVA and hearing loss. EVAS can be isolated or associated with cochlear malformation such as incomplete partition. There are no established criteria for diagnosis of EVAS. With advancement in imaging techniques, this VA and its anomalies are gaining greater interest among clinicians in recent years. High resolution computed tomography (HRCT) of temporal bone or MRI are helpful for the diagnosis of EVAS, with comparison to the adjacent posterior semicircular canal.

ObjectiveTo investigate the clinical characteristics and postoperative speech development in children with incomplete partition type III (IPIII) cochlear malformation.MethodsA retrospective analysis was conducted on 6 patients (12 ears) diagnosed with IPIII cochlear malformation, all patients underwent preoperative high-resolution CT (HRCT), middle ear and cranial MRI, and audiological evaluations. Intraoperative cochlear imaging was performed to confirm electrode placement, there was also 1 types of comparison: IP III patients with matched CI patients without inner ear malformations, questionnaires were used to evaluate auditory and speech perceptionResultsAll 6 patients were male, with 3 undergoing bilateral cochlear implantation and 3 undergoing unilateral implantation (1 left, 2 right). The surgical age ranged from 8 months to 12 years, with a median age of 17 months. HRCT findings in all 12 ears (100%) showed a grossly normal cochlear shape with bony cochlear partitions present but an absent modiolus. Ten ears (10/12; 83.3%) exhibited enlarged internal auditory canals (6.13 ± 0.395 mm), 9 ears (9/12; 75%) had profound sensorineural hearing loss, 4 ears (4/12; 33.3%) showed significant vestibular dilation with a cystic appearance, and 4 ears (4/12; 33.3%) had enlarged vestibular aqueducts. All patients had normal auditory nerve development (100%). intraoperative neural response telemetry (NRT) responses were successfully elicited in all cases, and all patients experienced gusher phenomenon (6/6; 100%). Intraoperative cochlear imaging preliminarily confirmed electrode placement. Follow-up ranged from 3 months to 1 year, with preoperative CAP scores 0.83 ± 0.41 and postoperative CAP scores 6 ± 1.55, p<0.05. In Speech Intelligibility Rating (SIR) questionnaires, CI patients without inner ear malformations outperformed IP III patients, while there was no significant difference in other questionnaires.ConclusionIPIII cochlear malformation is more common in male patients and is often associated with profound to severe sensorineural hearing loss. Cochlear implantation for IP-III malformation leads to significant auditory-speech improvement in early stage and can result in varying degrees of oral competence.

Cochlear implantation (CI) has been shown to be feasible and beneficial in patients with inner ear malformations (IEMs); however, incomplete partition type III (IP-III) malformations are rarely considered. In this scoping review, we evaluate the benefit of CI in patients with the relatively rare IP-III malformation. A review in accordance with PRISMA was performed. A search of MEDLINE, EMBASE, Cochrane CENTRAL, CINAHL, and Web of Science was performed. Cohort studies, case studies, and conference abstracts evaluating complications or outcomes of CI in patients with confirmed IP-III malformation were included. Our search identified a total of 40 studies after screening 1060 articles. Twenty-five studies (62.5%) reported CSF gusher as an intraoperative complication for a total of 120/122 patients (98.4%) in these studies. The most reported audiologic outcomes were speech perception testing with 10 studies, Categories of Auditory Performance (CAP) scores with 9 studies, and Speech Intelligibility Rating (SIR) with 8 studies. All 4 studies that directly compared IP-III malformation to other malformations using these outcome measures concluded that performance was statistically similar to at least one other malformation (100%). When compared with children with normal ears, only one-sixth of studies (16.7%) reported statistically similar results in IP-III malformation. CSF gusher is an expected intraoperative complication of CI in patients with IP-III. Expectations regarding performance with CI in the setting of IP-III malformations should be tempered. Nonetheless, CI remains a viable option in patients with IP-III malformations with auditory outcomes comparable to those seen in other IEMs.

Background/Objectives: Cochlear implantation (CI) has been shown to be effective in children with inner ear malformations (IEMs). However, outcomes vary with malformation type and anatomical complexity. Advances in radiological classification may improve the understanding of such variability to better guide patient counseling. We aimed to assess one-year post-implant auditory outcomes in children with IEMs using radiology-based classifications, and to explore genetic and perinatal predictors. We also propose a preliminary severity score derived from the INCAV system. Methods: Out of 303 pediatric CI recipients assessed at a tertiary center, we retrospectively analyzed 41 children (82 ears) diagnosed with IEMs. Malformations were categorized with the Sennaroğlu system and re-coded using INCAV, from which a severity score was derived. Postoperative outcomes were assessed in 56 implanted ears, including pure-tone average (PTA), word recognition score (WRS), and post-surgical complications. Statistical analyses included Spearman’s correlation, linear regression, and exploratory discriminant MANOVA. Results: The most frequent malformation was enlarged vestibular aqueduct (33%), followed by incomplete partition type II (22%). CI was performed in 56 malformed ears with a complication rate of 10.7%. PTA and WRS correlated with the INCAV-derived severity score, with higher severity linked to poorer thresholds and lower WRS. Linear regression showed severity explained ~20% of PTA variance, with outcomes more frequently impaired in ears with scores > 3. Exploratory analysis revealed inter-subject variability, with partial separation of mild versus moderate/severe groups mainly driven by PTA and WRS. Conclusions: CI in pediatric IEMs is safe and consistently improves hearing thresholds. PTA was the most robust predictor of performance, while the INCAV-derived severity score, though exploratory, may provide additional value for anatomical stratification, prognostic counseling, and rehabilitation planning.

Cochlear implantation (CI) is the state-of-the-art treatment option for sensorineural hearing loss condition including patients with congenital inner ear malformations. Recently our centre started treating children with CI who were diagnosed with inner ear malformations. Objectives of this retrospective study are to create three-dimensional (3D) model of malformed inner ears, identification of cochlear nerve bundle from pre-operative images, visualize electrode placement inside the cochlear portion from post-operative images, and evaluate hearing benefits post-operatively received from CI. Slicer software was used to 3D segment the inner ear and the electrode from the pre-, and post of CT scans. Using the same software, cross-section of internal auditory canal (IAC) was navigated to visualize the presence or absence of cochlear nerve. Speech intelligibility rating (SIR) and pure tone average (PTA) thresholds were evaluated for the benefits received from CI. Our database showed a total of 12 children radiologically diagnosed with inner ear malformation and out of which 19 ears were treated with MED-EL CI devices. Enlarged vestibular aqueduct (EVA, incomplete partition (IP) types I, and II, cochlear hypoplasia (CH), cochlear aperture stenosis, common cavity (CA) were the different malformation types found in this cohort. Intra-operative gusher was observed in EVA and IP type II malformation types. Higher SIR scores and lower PTA thresholds were seen for less severe malformation types and vice-versa. Severity of malformation have a negative effect on the hearing outcomes with CI. MRI is an important tool in the identification of cochlear nerve bundle in subjects diagnosed with malformed inner ear anatomies.

Response to: Morphometric measurements of the incomplete partition type II (IP-II) cochlea and implications on cochlear implantation.

Inner ear malformations (IEMs) represent unique challenges in cochlear implantation, potentially influencing electrode placement during surgery and neural responsiveness. Thus, electrically evoked cortical auditory potentials (eCAEPs) were suggested to be performed as objective measures of higher-level auditory perception at the cortical level in assessing cochlear implant (CI) outcomes in this complex population. This study aims to evaluate preliminary findings of P1 latency in eCAEPs among CI recipients with several types of IEMs at different positions of electrodes, that is, apical, medial, and basal regions. A cohort of five CI recipients with IEMs was evaluated using postoperative eCAEPs recordings, and P1 latency was analyzed at different positions of electrodes. The mean age of the subjects was 14.01 ± 5.51 years, with common cavity malformations, incomplete partition type I (IP-I), incomplete partition type II (IP-II), and enlarged vestibular aqueduct. Early data suggest P1 responses were generally present in all IEM cases in this cohort, with the mean of P1 latency for the electrode at apical, medial, and basal regions of 108.2 ± 13.4, 124.0 ± 23.6, and 140.0 ± 41.5 ms, respectively. These findings may reflect differential cortical response across IEM types at multiple CI electrode locations.

Background: Congenital inner ear malformations (IEM) pose a challenge during cochlear implantation (CI) in terms of increased risk of surgical complications and uncertainty of outcomes. This case series presents the surgical complications encountered and outcomes of CI in those children with inner ear anomalies. Aims: (1) To examine the intraoperative findings and surgical complications in children with inner ear abnormalities undergoing CI and (2) to examine the reported speech perception outcomes in these children, postoperatively using the categories of auditory performance (CAP) scores, and speech intelligibility rating. Settings and Design: A retrospective study was conducted over a period of 2 years at a tertiary care center, involving three patients with IEMs who underwent CI. Subjects and Methods: Intraoperative complications encountered and their management alongside evaluation of surgical outcomes were analyzed. Results: Two children had incomplete partition type II, and one child was found to have a common cavity according to Sennaroglu classification. Intraoperative problems, such as facial nerve palsy and cerebrospinal fluid gusher, were few of the main difficulties faced. Nonetheless, following postoperative rehabilitation, all IEM patients demonstrated a notable increase in their verbal and auditory abilities. Conclusions: Children with IEMs may benefit from auditory rehabilitation with cochlear implants. A multidisciplinary approach aiding in definitive diagnosis, surgical planning, and postoperative rehabilitation is recommended for positive outcomes.

EVA patients exhibit distinct audiometric patterns and genetic variants based on their inner ear morphology. The higher prevalence of biallelic SLC26A4 mutations in IP-II & EVA children suggests a stronger genetic component in this phenotype, potentially influencing clinical management strategies. • The genetic and clinical characteristics of patients with enlarged vestibular aqueduct (EVA) have been studied. However, its manifestations in completely deaf children in China, especially those with or without incomplete partition type II (IP-II), are not yet fully understood. • Isolated enlarged vestibular aqueduct (IEVA) patients demonstrated lower hearing thresholds but higher air-bone gap (ABG) rates compared to IP-II with EVA (IP-II & EVA) cases. The SLC26A4 c.919-2A > G mutation emerged as predominant, with biallelic mutations occurring more frequently in IP-II & EVA cases. These findings may guide clinical management strategies for affected children.

ABSTRACTObjectiveTo clinically validate manual measurement of cochlear length from pre‐operative image of cochlea with post‐operative image of cochlear implant (CI) electrode.MethodsTemporal bone computer tomography (CT) scans of 23 ears were available for this pilot study. The inner ear was three‐dimensionally (3D) segmented, and cochlea length was manually measured for preferred angular depth depending on inner ear anatomical types for CI electrode length selection. Post‐operative CT scans were made available for electrode reconstruction to measure electrode length inside the cochlea to validate pre‐operative measurement of cochlear length.ResultsNormal anatomy (NA) inner ear was identified in 11 ears, enlarged vestibular aqueduct syndrome (EVAS) in 4 ears, incomplete partition (IP) type I in 2 ears, cochlear hypoplasia (CH) in 5 ears, and otosclerosis in 1 ear. Cochlear length was measured for 650° of angular depth in NA ears, 540° in EVAS and otosclerosis, 360° in IP type I, and for available angular depth depending on the development of the cochlea in CH type. Based on the cochlea length measured, a closely matching electrode length was chosen for implantation from 1 CI manufacturer. Partial insertion was seen in 2 NA ears, 1 otosclerosis ear, and 1 CH ear, whereas full insertion of the chosen electrode was achieved in the remaining 19 ears.ConclusionManual measurement of cochlea length from 3D image of cochlea is a practical way of choosing electrode length for preferred angular insertion depth depending on the cochlea anatomy.Level of EvidenceBetween level 2 and 3.

Cochlear implants (CIs) are effective interventions for treating severe-to-profound sensorineural hearing loss. In patients with complex inner ear anatomy due to conditions such as incomplete partition type II (IP-II) and enlarged vestibular aqueduct, they present unique challenges, increasing the risk of surgical and postoperative complications, including facial nerve stimulation (FNS), cerebrospinal fluid leaks, and vestibular dysfunction. The 32 year-old subject of this case study presented with IP-II and experienced persistent FNS, dizziness, and declining CI performance despite an initial revision surgery and appropriate programming strategies of her processor. Interdisciplinary collaboration between audiology, neurotology, and speech-language pathology helped to identify and address contributing factors to the patient's symptoms. After strategic programming adjustments, including pulse width modification and electrode management in conjunction with aural rehabilitation sessions, the patient's speech perception scores and CI quality of life metrics improved markedly over time, as did her confidence and engagement in social and professional settings. This case highlights a challenging example of CI performance issues in the setting of IP-II and aims to examine how CI programming, in response to anatomical and surgical difficulties, affects patient outcomes in cases involving inner ear malformations.

To analyze histopathological factors contributing to recurrent meningitis in patients with inner ear malformations (IEMs) through examination of two cases from the archives of an otopathology laboratory. Two cases with documented IEMs and a history of recurrent meningitis were analyzed from archived human temporal bone specimens in July 2024. Histopathological examination and analysis of temporal bone specimens to identify anatomical defects and infection pathways. Identifying specific anatomical defects and pathways contributing to recurrent meningitis in IEM cases. Case 1 demonstrated an incomplete partition type I (IP-I) malformation with a stapes footplate fistula, which provided a direct pathway for infection from the middle ear to the inner ear spaces. Case 2 revealed an incomplete partition type III (IP-III) malformation with a deficient otic capsule, presenting multiple potential routes for infection spread due to irregular erosion and minimal bone barrier between middle and inner ear spaces. Both cases resulted in fatal meningitis despite medical intervention. Recurrent meningitis in IEMs can occur through different pathophysiological mechanisms: either through a discrete stapes footplate fistula or via a deficient otic capsule with multiple potential infection pathways. Management strategies should be tailored to the specific anatomical defect, with surgical intervention focusing on defect repair in stapes footplate fistulas and consideration of subtotal petrosectomy in cases of deficient otic capsule. Vaccination and careful selection of surgical procedures are crucial preventive measures. IV.

To investigate the molecular findings and long-term outcomes of cochlear implantation (CI) in a relatively large cohort of patients with incomplete partition type-III malformation (IP-III), and to analyze the correlation between genotype and CI outcomes. Cross-sectional (genomic) and retrospective cohort (auditory and speech outcomes with CI) study. Tertiary referral center. Children diagnosed with IP-III who underwent CI at a tertiary referral center were enrolled. Comprehensive genetic analyses were performed for each participant. Postoperative auditory and speech abilities with CI were retrospectively analyzed. Correlations between different mutation types and CI outcomes were analyzed. Nineteen children from 17 families were included. All participants had genetic variations, with seven novel variants on the POU3F4 exon and four novel copy number variations (CNVs) on Xq21.1. Most children showed great auditory and speech improvement after long-term rehabilitation with CI, but their speech recognition rates varied considerably. Children with variants affecting amino acid sequences of POU domains showed better preimplantation performance and older age of implantation, but their long-term auditory and speech abilities were comparable to those with complete loss of POU domains. Children with CNVs upstream of POU3F4 had greatly improved auditory and speech abilities, whereas those with large deletions showed only some improvement in sound detection ability. This study expands the mutation spectrum of POU3F4 and provides initial evidence for potential associations between genetic variations and CI outcomes in children with IP-III malformation. III.

Response to Letter to Editor for "Morphometric Measurements of the Incomplete Partition Type II (IP-II) Cochlea and Implications on Cochlear Implantation".

To investigate comorbidities and severity correlations among inner ear malformations (IEMs) classifications and analyze subtype characteristics to optimize preoperative evaluation and cochlear implantation (CI) strategies. Retrospective multicenter data from Hubei Province were analyzed for 336 children with IEMs who received unilateral CI (2012-2020). IEMs were classified and graded using Sennaroğlu and Adibelli criteria, and data visualization tools were used to assess subtypes, comorbidities, and severity correlations. Among pediatric candidates for CI with IEMs, isolated enlarged vestibular aqueduct, isolated incomplete partition type II, and multiple malformations were the 3 most common subtypes, accounting for 80.7% of cases. Vestibular aqueduct malformation (VAM) primarily occurred as an isolated condition, whereas internal auditory canal malformation (IACM), cochlear nerve malformation (CNM), cochlear malformation (CM), and vestibular and semicircular canal malformation (VSCM) tended to coexist, exhibiting significant co-occurrence patterns. Severity analysis revealed a positive correlation between the severity of IACM and CNM (r = .13, P = .015), as well as between CM and VSCM (r = .17, P < .001). Additionally, VAM severity was significantly negatively correlated with the severity of IACM, CNM, CM, and VSCM (r = -.39, -.21, -.38, and -.30, respectively; P < .001). This study elucidated a detailed analysis of the subtype characteristics and comorbid relationships of IEMs in pediatric candidates for CI. Furthermore, it identified significant correlations between the severity levels of different malformation types. These insights contribute to refining preoperative evaluation protocols and tailoring treatment strategies for CI candidates.

Background: Cochlear implantation in children with congenital ear malformations presents unique perioperative challenges due to anatomical variations. Comprehensive perioperative care is essential for optimal outcomes, yet literature on nursing management for these complex cases remains limited. Objective: To document the perioperative nursing approach for cochlear implantation in a pediatric patient with congenital ear malformation and establish evidence-based protocols for similar cases. Case: A 9-year-old child diagnosed with bilateral profound sensorineural hearing loss with Mondini malformation (incomplete partition) underwent left cochlear implantation. The patient had previously undergone right cochlear implantation two years prior with successful outcomes. Perioperative management included comprehensive preoperative assessment with special attention to craniofacial anomalies, intraoperative monitoring for cerebrospinal fluid leakage and facial nerve function, and postoperative care focusing on pain management, infection prevention, and family education. Despite anatomical challenges, the procedure was successfully completed with 10 of 12 electrodes functioning properly, and the patient was discharged on postoperative day two without complications. Conclusion: Successful cochlear implantation in children with congenital ear malformations requires a multidisciplinary approach with specialized perioperative nursing care. This case demonstrates that with proper preoperative planning, intraoperative vigilance, and comprehensive postoperative management, good functional outcomes can be achieved despite complex anatomical challenges. Standardized protocols for perioperative care in these cases can significantly improve patient safety and surgical outcomes.

Incomplete partition type II (IP-II) is one of the most common inner ear malformations that necessitates cochlear implantation. It is characterized by a cystic cochlear apex resulting from the coalescence of middle and apical turns due to modiolar hypoplasia and distal interscalar septal defect. Radiologic diagnosis of IP-II anomaly could be difficult with equivocal changes in tiny labyrinthine structures, especially with inexperienced observers. In our study, we aimed to determine pertinent quantitative radioanatomical measurements of inner ear structures (lateral interscalar notch angle, lateral interscalar notch depth, and lateral height) that may contribute to the diagnosis of IP-II anomaly using temporal bone high-resolution computed tomography (HRCT). Our study was a retrospective case-control study approved by the institutional review board. We retrospectively reviewed temporal bone HRCT examinations for the preoperative assessment of cochlear implantation of patients with sensorineural hearing loss (SNHL), using the diagnosis code of IP-II anomaly. Patients with SNHL and a radiologic diagnosis of IP-II anomaly according to the Sennaroglu classification were recruited. Thirty-four SNHL patients with IP-II anomaly (66 ears) and 24 patients without SNHL (48 ears) who underwent temporal CT imaging for inflammatory conditions or trauma not involving labyrinthine structures were included in the study. The lateral interscalar notch angle, lateral interscalar notch depth, and lateral height were independently measured by 2 observers (a senior head and neck radiologist and a novice radiologist). The parameters measured in patient and control groups were compared using the Mann-Whitney U test, and interobserver reliability was calculated. Lateral interscalar notch angle and lateral height values were found to be significantly larger, while lateral interscalar notch depth value was significantly smaller in the IP-II group ( P <0.05). The agreement between the observers in all measurements, evaluated separately in IP-II and control groups, was excellent ( P <0.05). The cutoff values for determining the IP-II anomaly were found to be consistent between the 2 observers, with high sensitivity and specificity. CT measurements of inner ear structures in SNHL could help to diagnose IP-II anomalies, especially in patients with equivocal audiological and radiologic findings. This study validates CT measurements in the evaluation of IP-II anomaly conducted by histologic specimens and MRI in previous studies. Lateral cochlear measurements with an angle of >130 degrees, a depth of ≤0.35mm, and a height of >3.15mm could support the diagnosis of the IP-II anomaly. These measurements are also reproducible.

Fraction division is considered one of the most difficult concepts in learning fractions. This study aims to investigate students’ understanding of fraction division through a partition division conceptualization, utilizing their understanding of fractions as parts of a whole. To achieve this, we designed a hypothetical learning trajectory, in which students engaged with incomplete partition task. This article reports on a two-week design research intervention involving 21 fifth-grade students. The students’ written works, transcripts of teaching experiment recordings, and observational notes were retrospectively analyzed to examine the hypothetical learning trajectory. The study revealed that the students’ primary challenge was recognizing the correct whole during the teaching experiment. This study suggests that incorporating a stronger focus on proportional reasoning and varying fraction sizes in instructional approaches may help address this obstacle.