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Background/Objectives: A heterozygous mutation in the WFS1 gene is responsible for autosomal dominant non-syndromic hearing loss (DFNA6/14/38) and Wolfram-like syndrome, which is characterized by bilateral sensorineural hearing loss with optic atrophy and/or diabetes mellitus. However, detailed clinical features for the patients with the heterozygous p.A684V variant remain unknown. Methods: We report the clinical details of 14 cases with a heterozygous p.A684V variant in the WFS1 gene identified from target resequencing analysis of 63 previously reported deafness genes by next-generation sequencing of 15,684 hearing loss patients (mean age 27.5 ± 23.1 years old, 6574 male, 8612 female and 498 for whom information was unavailable). Results: Among the 14 patients from 13 families with the p.A684V variant, nine were sporadic cases. In addition, we confirmed de novo occurrence of this variant in seven families. This result strongly supports the notion that this variant was located on a mutational hotspot. When comparing previously reported cases of autosomal dominant WFS1 gene-associated hearing loss, most of the patients in this study showed severe-to-profound bilateral sensorineural hearing loss (genotype–phenotype correlation). Two patients had optic atrophy, while the others did not have any other complications. Conclusions: The identified heterozygous p.A684V variant appears to be a hotspot mutation and likely to cause severe-to-profound hearing loss in early childhood. Cochlear implantation is considered favorable in cases of hearing impairment due to this variant. [ABSTRACT FROM AUTHOR]

To achieve better speech performance following cochlear implantation (CI), measuring the patient's cochlear duct length (CDL) and determining the appropriate length of the CI array are important. To investigate the CDL in CI patients after using the OTOPLAN software preoperatively and compare the results of angular insertion depth (AID) estimation by OTOPLAN and postoperative radiography. The study included 105 Japanese CI patients with normal cochleae. We measured the CDL using OTOPLAN and the position of the tip channel of the electrode for each selected electrode array, and estimated the AID using the software. The mean CDL was 35.1 ± 1.6 mm. Preoperatively, the mean estimated AID was 580.3 ± 57.8°. Postoperative radiography revealed a mean AID of 583.0 ± 56.7°, demonstrating a strong linear correlation between the two measurements (R2 = 0.635). Our findings revealed that CDL varies widely, which is consistent with previous studies. To achieve better speech perception, surgeons should select the appropriate length of CI electrode array based on the individual's CDL. Preoperative measurement of each CDL by OTOPLAN, which is clinically feasible and comparable to postoperative evaluation, can be used to ensure selection of the appropriate electrode array length. [ABSTRACT FROM AUTHOR]

A number of genes are reportedly responsible for hereditary hearing loss, which accounts for over 50% of all congenital hearing loss cases. Recent advances in genetic testing have enabled the identification of pathogenic variants in many cases, and systems have been developed to provide personalized treatment based on etiology. Gene therapy is expected to become an unprecedented curative treatment. Several reports have demonstrated the successful use of cochlear gene therapy to restore auditory function in mouse models of genetic deafness; however, many hurdles remain to its clinical application in humans. Herein, we focus on the frequency of deafness genes in patients with congenital and late‐onset progressive hearing loss and discuss the following points regarding which genes need to be targeted to efficiently proceed with clinical application: (a) which cells' genes are expressed within the cochlea, (b) whether gene transfer to the targeted cells is possible using vectors such as adeno‐associated virus, (c) what phenotype of hearing loss in patients is exhibited, and (d) whether mouse models exist to verify the effectiveness of treatment. Moreover, at the start of clinical application, gene therapy in combination with cochlear implantation may be useful for cases of progressive hearing loss. [ABSTRACT FROM AUTHOR]

Usher syndrome (USH) typically leads to deaf-blindness, requiring the provision of extensive education and rehabilitation services. Therefore, investigating the prevalence is crucial to requests for proper government support for USH patients. The aim was to perform a nationwide epidemiologic survey of USH in Japan to estimate the prevalence of USH and reveal the relative frequency and characteristics of the three USH subtypes. To estimate the number of USH patients visiting hospitals over a 1-year period, 1,628 hospitals were randomly selected from all Departments of Otorhinolaryngology and Ophthalmology in Japan. Subsequently, we collected data regarding the clinical characteristics of each patient treated and the results of genetic testing, if performed. We found that the prevalence of USH was at least 0.4 per 100,000 population. The frequency of clinical subtypes and causal genes for USH were consistent with previous reports. Also, we demonstrated the feasibility of genetic counseling for USH patients based on the results of genetic testing. USH is a rare disease, but requires social support due to the severity of symptoms. To minimize these issues, understanding the clinical characteristics and performing comprehensive genetic testing could allow early and accurate diagnosis as well as medical intervention. [ABSTRACT FROM AUTHOR]

Background: Electric-acoustic stimulation (EAS) has emerged as a standard treatment for patients with high-frequency hearing loss. EAS is usually performed with shorter electrodes of 16–24 mm in length. As most EAS recipients gradually lose residual acoustic hearing in the implanted ear over time, EAS with longer electrodes without causing significant intra-cochlear damage might be ideal. Objective: The aim of this study was to investigate hearing preservation (HP) results after EAS surgery with longer electrodes. Methods: Ten patients (11 ears) with partial deafness that met the indications for EAS with a MED-EL FLEX28 electrode were included in this study. Auditory thresholds before and at 6 months after activation were examined. Results: In 100% of cases, HP was comfortably achieved, indicating that all patients could utilize acoustic amplification combined with electric stimulation. Conclusion: EAS with longer electrodes can offer broader cochlear coverage, resulting in natural frequency matching in comparison with shorter electrodes, even in EAS cases. The combination of advanced surgical techniques and flexible, long, straight electrodes permits deep insertion that reaches the apical region with little or no insertion trauma. [ABSTRACT FROM AUTHOR]

Background: Recent advances in less-invasive surgery and electrode design allow for a high degree of hearing preservation (HP) after cochlear implantation (CI), although residual hearing still deteriorates in some patients. To date, the factors predictive of preserving residual hearing remain a controversial topic. Objective: The aim of this study was to investigate the predictive factors, including the etiology of hearing loss (HL) as a patient-related factor, influencing residual HP after CI. Methods: Forty-four patients (50 ears, 41 families) with residual acoustic hearing who underwent CI were included. Auditory thresholds before and at 6 months after initial activation were measured. Genetic testing was performed to identify the responsible genes for HL. Results: We identified the cause of HL in 21 families (51.2%). HP was marginally correlated with age at implantation, while it was independent of pre-operative low-frequency hearing thresholds, cochlear duct length, and electrode length. We found that patients who had pathogenic variants in the CDH23, MYO7A, or MYO15A gene showed statistically better HP scores compared with patients with HL due to other causes (p =.002). Conclusions: Identification of the etiology of HL using genetic testing is likely to facilitate the prediction of HP after implant surgery. [ABSTRACT FROM AUTHOR]