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Background: Mutations in Wolfram syndrome 1 ( WFS1 ) cause Wolfram syndrome and autosomal dominant non-syndromic hearing loss DFNA6/14/38. To date, more than 300 pathogenic variants of WFS1 have been identified. Generally, the audiological phenotype of Wolfram syndrome or DFNA6/14/38 is characterized by low-frequency hearing loss; however, this phenotype is largely variable. Hence, there is a need to better understand the diversity in audiological and vestibular profiles associated with WFS1 variants, as this can have significant implications for diagnosis and management. This study aims to investigate the clinical characteristics, audiological phenotypes, and vestibular function in patients with DFNA6/14/38. Methods: Whole-exome or targeted deafness gene panel sequencing was performed to confirm the pathogenic variants in patients with genetic hearing loss. Results: We identified nine independent families with affected individuals who carried a heterozygous pathogenic variant of WFS1 . The onset of hearing loss varied from the first to the fifth decade. On a pure-tone audiogram, hearing loss was symmetrical, and the severity ranged from mild to severe. Notably, either both low-frequency and high-frequency or all-frequency-specific hearing loss was observed. However, hearing loss was non-progressive in all types. In addition, vestibular impairment was identified in patients with DFNA6/14/38, indicating that impaired WFS1 may also affect the vestibular organs. Conclusions: Diverse audiological and vestibular profiles were observed in patients with pathogenic variants of WFS1. These findings highlight the importance of comprehensive audiological and vestibular assessments in patients with WFS1 mutations for accurate diagnosis and management.

KCNQ4 is a voltage-gated K + channel was reported to distribute over the basolateral surface of type 1 vestibular hair cell and/or inner surface of calyx and heminode of the vestibular nerve connected to the type 1 vestibular hair cells of the inner ear. However, the precise localization of KCNQ4 is still controversial and little is known about the vestibular phenotypes caused by KCNQ4 dysfunction or the specific role of KCNQ4 in the vestibular organs. To investigate the role of KCNQ4 in the vestibular organ, 6-g hypergravity stimulation for 24 h, which represents excessive mechanical stimulation of the sensory epithelium, was applied to p.W277S Kcnq4 transgenic mice. KCNQ4 was detected on the inner surface of calyx of the vestibular afferent in transmission electron microscope images with immunogold labelling. Vestibular function decrease was more severe in the Kcnq4 p.W277S/p.W277S mice than in the Kcnq4 +/+ and Kcnq4 +/p.W277S mice after the stimulation. The vestibular function loss was resulted from the loss of type 1 vestibular hair cells, which was possibly caused by increased depolarization duration. Retigabine, a KCNQ activator, prevented hypergravity-induced vestibular dysfunction and hair cell loss. Patients with KCNQ4 mutations also showed abnormal clinical vestibular function tests. These findings suggest that KCNQ4 plays an essential role in calyx and afferent of type 1 vestibular hair cell preserving vestibular function against excessive mechanical stimulation., (© 2024. The Author(s).)

Background: The vestibular phenotypes of patients with genetic hearing loss are poorly understood. Methods: we performed genetic testing including exome sequencing and vestibular function tests to investigate vestibular phenotypes and functions in patients with genetic hearing loss. Results: Among 627 patients, 143 (22.8%) had vestibular symptoms. Genetic variations were confirmed in 45 (31.5%) of the 143 patients. Nineteen deafness genes were linked with vestibular symptoms; the most frequent genes in autosomal dominant and recessive individuals were COCH and SLC26A4 , respectively. Vestibular symptoms were mostly of the vertigo type, recurrent, and persisted for hours in the genetically confirmed and unconfirmed groups. Decreased vestibular function in the caloric test, video head impulse test, cervical vestibular-evoked myogenic potential, and ocular vestibular-evoked myogenic potential was observed in 42.0%, 16.3%, 57.8%, and 85.0% of the patients, respectively. The caloric test revealed a significantly higher incidence of abnormal results in autosomal recessive individuals than in autosomal dominant individuals ( p = 0.011). The genes, including SLC26A4 , COCH , KCNQ4 , MYH9 , NLRP3 , EYA4 , MYO7A , MYO15A , and MYH9 , were heterogeneously associated with abnormalities in the vestibular function test. Conclusions: In conclusion, diverse vestibular symptoms are commonly concomitant with genetic hearing loss and are easily overlooked.

Objective: To investigate the safety and efficacy of a novel active transcutaneous bone conduction implant (BCI) device for patients with single-sided deafness (SSD)., Study Design: Prospective cohort study., Setting: Tertiary referral hospitals., Methods: This prospective multicenter study was conducted at 15 institutions nationwide. Thirty adult (aged ≥19 years) SSD patients were recruited. They underwent implantation of an active transcutaneous BCI device (Bonebridge BCI602). Objective outcomes included aided pure-tone thresholds, aided speech discrimination scores (SDSs), and the Hearing in Noise Test (HINT) and sound localization test results. The Bern Benefit in Single-Sided Deafness (BBSS) questionnaire, the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire, and the Tinnitus Handicap Inventory (THI) were used to measure subjective benefits., Results: The mean aided pure-tone threshold was 34.2 (11.3), mean (SD), dB HL at 500 to 4000 Hz. The mean total BBSS score was 27.5 (13.8). All APHAB questionnaire domain scores showed significant improvements: ease of communication, 33.6 (23.2) versus 22.6 (21.3), P = .025; reverberation, 44.8 (16.6) versus 32.8 (15.9), P = .002; background noise, 55.5 (23.6) versus 35.2 (18.1), P < .001; and aversiveness, 36.7 (22.8) versus 25.8 (21.4), P = .028. Moreover, the THI scores were significantly reduced [47.4 (30.1) versus 31.1 (27.0), P = .003]. Congenital SSD was a significant factor of subjective benefit (-11.643; 95% confidence interval: -21.946 to -1.340)., Conclusion: The BCI602 active transcutaneous BCI device can provide functional hearing gain without any adverse effects and is a feasible option for acquired SSD patients with long-term deafness., (© 2023 American Academy of Otolaryngology-Head and Neck Surgery Foundation.)

Introduction: Previous studies have reported that hearing loss (HL) is associated with dementia, although the mechanistic underpinnings remain elusive. This study aimed to evaluate the changes in brain metabolism in patients with HL and different types of dementia., Methods: Patients with cognitive impairment (CI) and HL treated at the university-based memory clinic from May 2016 to October 2021 were included. In total, 108 patients with CI and HL prospectively underwent audiometry, neuropsychological test, magnetic resonance imaging, and 18 F-fluorodeoxyglucose positron emission tomography. Twenty-seven individuals without cognitive impairment and hearing loss were enrolled as a control group. Multivariable regression was performed to evaluate brain regions correlated with each pathology type after adjusting for confounding factors., Results: Multivariable regression analyses revealed that Alzheimer's disease-related CI (ADCI) was associated with hypometabolic changes in the right superior temporal gyrus (STG), right middle temporal gyrus (MTG), and bilateral medial temporal lobe. Lewy body disease-related CI (LBDCI) and vascular CI were associated with hypermetabolic and hypometabolic changes in the ascending auditory pathway, respectively. In the pure ADCI group, the degree of HL was positively associated with abnormal increase of brain metabolism in the right MTG, whereas it was negatively associated with decreased brain metabolism in the right STG in the pure LBDCI group., Conclusion: Each dementia type is associated with distinct changes in brain metabolism in patients with HL., (© 2024 The Authors. Brain and Behavior published by Wiley Periodicals LLC.)

Background: This study aimed to evaluate hearing loss by combining pure tone audiometry (PTA) with subjective hearing level concerning suicidal ideation., Methods: A total of 23,215 individuals from the Korea National Health and Nutrition Examination Survey (KNHANES) between 2009 and 2013 were included. PTA was categorized according to average audiometric threshold levels: normal (≤25 dB), mild (26-40 dB), and moderate-severe (>40 dB). The subjective hearing level was categorized as "no discomfort," "mild discomfort," and "considerable discomfort" for hearing without a hearing aid. Next, we classified hearing loss into nine groups by combining PTA and subjective hearing levels. Suicidal ideation was defined as answering yes to the following question: "Have you ever seriously thought about killing yourself in the past 1 year?" We conducted chi-square tests and multiple logistic regression analyses., Results: Among the 23,215 participants aged ≥19 years (mean age 46.52 years), 3,214 (13%) reported having suicidal ideation. According to PTA, moderate to severe hearing loss was related to suicidal ideation (OR = 1.19, 95 % CI = 1.01-1.41). Subjective hearing loss was associated with suicidal ideation (mild: OR = 1.41, 95 % CI = 1.21-1.65; considerable: OR = 1.57, 95 % CI = 1.20-2.05). Moreover, as the subjective hearing level increased, the ORs of suicidal ideation increased in individuals with moderate to severe hearing loss (mild: OR = 1.52, 95 % CI = 1.24-1.88; considerable: OR = 1.81, 95 % CI = 1.39-2.36)., Limitations: The cross-sectional study limits the interpretation of causal relationships., Conclusions: Subjective hearing loss was more strongly associated with suicidal ideation than hearing loss as measured by PTA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Purpose: To assess the diagnostic potential of whole-exome sequencing (WES) and elucidate the clinical and genetic characteristics of primary ciliary dyskinesia (PCD) in the Korean population., Materials and Methods: Forty-seven patients clinically suspected of having PCD were enrolled at a tertiary medical center. WES was performed in all patients, and seven patients received biopsy of cilia and transmission electron microscopy (TEM)., Results: Overall, PCD was diagnosed in 10 (21.3%) patients: eight by WES (8/47, 17%), four by TEM. Among patients diagnosed as PCD based on TEM results, two patients showed consistent results with WES and TEM of PCD (2/4, 50%). In addition, five patients, who were not included in the final PCD diagnosis group, had variants of unknown significance in PCD-related genes (5/47, 10.6%). The most frequent pathogenic (P)/likely pathogenic (LP) variants were detected in DNAH11 (n=4, 21.1%), DRC1 (n=4, 21.1%), and DNAH5 (n=4, 21.1%). Among the detected 17 P/LP variants in PCD-related genes in this study, 8 (47.1%) were identified as novel variants. Regarding the genotype-phenotype correlation in this study, the authors experienced severe PCD cases caused by the LP/P variants in MCIDAS , DRC1 , and CCDC39 ., Conclusion: Through this study, we were able to confirm the value of WES as one of the diagnostic tools for PCD, which increases with TEM, rather than single gene tests. These results will prove useful to hospitals with limited access to PCD diagnostic testing but with relatively efficient in-house or outsourced access to genetic testing at a pre-symptomatic or early disease stage., Competing Interests: The authors have no potential conflicts of interest to disclose., (© Copyright: Yonsei University College of Medicine 2024.)

Background: Mutations in mitochondrial DNA (mtDNA) are associated with several genetic disorders, including sensorineural hearing loss. However, the prevalence of mtDNA mutations in a large cohort of Korean patients with hearing loss has not yet been investigated. Thus, this study aimed to investigate the frequency of mtDNA mutations in a cohort of with pre- or post-lingual hearing loss of varying severity., Methods: A total of 711 Korean families involving 1,099 individuals were evaluated. Six mitochondrial variants associated with deafness ( MTRNR1 m.1555A>G, MTTL1 m.3243A>G, MTCO1 m.7444G>A and m.7445A>G, and MTTS1 m.7471dupC and m.7511T>C) were screened using restriction fragment length polymorphism. The prevalence of the six variants was also analyzed in a large control dataset using whole-genome sequencing data from 4,534 Korean individuals with unknown hearing phenotype., Results: Overall, 12 of the 711 (1.7%) patients with hearing loss had mtDNA variants, with 10 patients from independent families positive for the MTRNR1 m.1555A>G mutation and 2 patients positive for the MTCO1 m.7444G>A mutation. The clinical characteristics of patients with the mtDNA variants were characterized by post-lingual progressive hearing loss due to the m.1555A>G variant (9 of 472; 1.9%). In addition, 18/4,534 (0.4%) of the Korean population have mitochondrial variants associated with hearing loss, predominantly the m.1555A>G variant., Conclusion: A significant proportion of Korean patients with hearing loss is affected by the mtDNA variants, with the m.1555A>G variant being the most prevalent. These results clarify the genetic basis of hearing loss in the Korean population and emphasize the need for genetic testing for mtDNA variants., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2023 The Korean Academy of Medical Sciences.)

Suggested several decades ago, the nine-step test is an intuitive test of Eustachian tube function. However, studies employing the nine-step test to assess the results of Eustachian tube balloon dilation (EBD) are limited. We aimed to objectively evaluate the efficacy of EBD in opening failure patients with decreased maximal peak pressure difference (MPD) using the nine-step test. Patients who had MPD values ≤ 13 daPa in the nine-step test were enrolled. The patients were categorized into two groups according to treatment decisions after discussion with a clinician: an EBD group (N = 26) and a medication group (N = 30). One month after treatment, the seven-item Eustachian Tube Dysfunction Questionnaire (ETDQ7) and the nine-step test were administered to all participants and subgroups of symptomatic participants (ETDQ7 > 15). MPD improved (increased) in both the EBD group and the medication group. ETDQ7 values improved (decreased) in the EBD group, but not in the medication group. In subgroup analysis, MPD and ETDQ7 values improved only in the symptomatic EBD group. According to the nine-step test, EBD can normalize 53.8% of decreased MPD. Posttreatment MPD and ETDQ7 scores were significantly better in the EBD group than in the medication group. However, EBD in patients with abnormal nine-step test results seemed less efficacious when the treatment results of the medication group were considered., (© 2023. Springer Nature Limited.)

Genetic hearing loss is the most common hereditary sensorial disorder. Though more than 120 genes associated with deafness have been identified, unveiled causative genes and variants of diverse types of hearing loss remain. Herein, we identified a novel nonsense homozygous variant in CEP250 (c.3511C>T; p.Gln1171Ter) among the family members with progressive moderate sensorineural hearing loss in nonsyndromic autosomal recessive type but without retinal degeneration. CEP250 encodes C-Nap1 protein belonging to the CEP protein family, comprising 30 proteins that play roles in centrosome aggregation and cell cycle progression. The nonsense variant in CEP250 led to the early truncating protein of C-Nap1, which hindered centrosome localization; heterologous expression of CEP250 (c.3511C>T) in NIH3T3 cells within cilia expression condition revealed that the truncating C-Nap1 (p.Gln1171Ter) was not localized at the centrosome but was dispersed in the cytosol. In the murine adult cochlea, Cep250 was expressed in the inner and outer hair cells. Knockout mice of Cep250 showed significant hair cell degeneration and progressive hearing loss in auditory brainstem response. In conclusion, a nonsense variant in CEP250 results in a deficit of centrosome localization and hair cell degeneration in the cochlea, which is associated with the progression of hearing loss in humans and mice.

Purpose: Facial nerve decompression surgery is performed on patients with immediate, complete traumatic facial palsy. However, the clinical advantage of the surgical treatment has weak evidence because of lack of control groups in previous studies. Therefore, this study compared facial function outcomes between the patients who underwent surgery and those who did not. Furthermore, in cases of bilateral traumatic facial palsy, the outcomes of the surgical and nonsurgical sides were also discussed., Methods: A retrospective medical chart review of immediate and severe (House-Brackman [HB] grade V and VI) traumatic facial palsy was conducted. Twenty-five ears from the surgical group and eight ears from the conservative treatment group were enrolled. Among the patients, three with immediate and severe bilateral facial palsy underwent unilateral surgery., Results: The average HB grade after 1-year follow-up was 1.7 in the surgical group and 1.5 in the nonsurgical group. Four patients who have definite facial canal disruption in the imaging study have recovered to HB grades I-III without surgical intervention. In patients with bilateral facial palsy, the nonsurgical side showed the same or better facial functions than the surgical side., Conclusions: Compared with nonsurgical conservative treatment, facial nerve decompression surgery did not show superior outcomes in immediate HB grade V-VI traumatic facial palsy. The clinical advantage of facial nerve decompression is questionable and should be re-evaluated in a prospectively designed study., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Pathogenic variants of KCNQ4 cause symmetrical, late-onset, progressive, high-frequency-affected hearing loss, which eventually involves all frequencies with age. To understand the contribution of KCNQ4 variants to hearing loss, we analyzed whole-exome and genome sequencing data from patients with hearing loss and individuals whose hearing phenotypes were unknown. In KCNQ4, we identified seven missense variants and one deletion variant in 9 hearing loss patients and 14 missense variants in the Korean population with an unknown hearing loss phenotype. The p.R420W and p.R447W variants were found in both cohorts. To investigate the effects of these variants on KCNQ4 function, we performed whole-cell patch clamping and examined their expression levels. Except for p.G435Afs*61, all KCNQ4 variants exhibited normal expression patterns similar to those of wild-type KCNQ4. The p.R331Q, p.R331W, p.G435Afs*61, and p.S691G variants, which were identified in patients with hearing loss, showed a potassium (K + ) current density lower than or similar to that of p.L47P, a previously reported pathogenic variant. The p.S185W and p.R216H variants shifted the activation voltage to hyperpolarized voltages. The channel activity of the p.S185W, p.R216H, p.V672M, and p.S691G KCNQ4 proteins was rescued by the KCNQ activators retigabine or zinc pyrithione, whereas p.G435Afs*61 KCNQ4 proteins were partially rescued by sodium butyrate, a chemical chaperone. Additionally, the structure of the variants predicted using AlphaFold2 showed impaired pore configurations, as did the patch-clamp data. Our findings suggest that KCNQ4 variants may be overlooked in hearing loss that starts in adulthood. Some of these variants are medically treatable; hence, genetic screening for KCNQ4 is important., (© 2023. The Author(s).)

Hair cells of the mammalian cochlea are specialized mechanosensory cells that convert mechanical stimuli into electrical signals to initiate the neuronal responses that lead to the perception of sound. The mechanoelectrical transduction (MET) machinery of cochlear hair cells is a multimeric protein complex that consists of the pore forming subunits of the MET channel and several essential accessory subunits that are crucial to regulate channel function and render the channel mechanically sensitive. Mutations have been discovered in the genes that encode all known components of the MET machinery. These mutations cause hearing loss with or without vestibular dysfunction. Some mutations also affect other tissues such as the retina. In this brief review, we will summarize gene mutations that affect the MET machinery of hair cells and how the study of the affected genes has illuminated our understanding of the physiological role of the encoded proteins.

Objectives: Despite growing interest in the genetic contribution to cochlear implant (CI) outcomes, only a few studies with limited samples have examined the association of CI outcomes with genetic etiologies. We analyzed CI outcomes using known predictors and genetic testing results to obtain a comprehensive understanding of the impact of genetic etiologies., Design: We retrospectively reviewed the medical records and images of patients who underwent cochlear implantation and genetic testing at a single tertiary medical institution, between May 2008 and December 2020. After excluding those whose speech test results were unavailable, and those in whom the implant was removed due to complications, such as infection or device failure, 203 patients were included in this study. The participants were categorized into adult (≥19 years), child (2-18 years), and infant (<24 months) groups. Outcomes were measured based on categories of auditory perception, monosyllable, disyllable, and sentence scores. For the infant group, the Infant-Toddler Meaningful Auditory Integration Scale score was used., Results: Among the 203 participants, a causative genetic variant was identified in 117 (57.6%) individuals. The presence of a causative variant was significantly associated with better CI outcomes in the infant group (β = 0.23; 95% confidence interval, 0.01 to 0.47; p = 0.044), but not in the child and adult groups. In the genetically confirmed patients without cochlear malformation, genetic variants involving the spiral ganglion was a poor prognostic factor in the child group (β = -57.24; 95% confidence interval, -90.63 to -23.75; p = 0.004)., Conclusions: The presence of known genetic etiology of hearing loss was associated with better CI outcomes in the infant group, but not in the child and adult groups. A neural-type genetic variant was a poor prognostic factor in the genetically diagnosed child subgroup without cochlear malformation. Careful genetic counseling should be performed before cochlear implantation., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Although the cleft palate is regarded as a contraindication for Eustachian tube ballooning, the presence of submucosal cleft palate may be overlooked while diagnosing Eustachian tube dysfunction. Therefore, we aimed to determine the incidence of the presence of a hard palate bony notch and vomer defect, which indicate the presence of submucosal cleft palate in patients with Eustachian tube dysfunction. In the Eustachian tube dysfunction group (n = 28), 4 patients (14.3%) exhibited a hard palate bony notch and a concurrent vomer defect. Three of them exhibited the presence of occult submucosal cleft palate, which had not been diagnosed previously. None of the control group (n = 39) showed any of these findings. The hard palate length of patients in the Eustachian tube dysfunction group was significantly lesser than that of those in the control group (34.2 ± 5.6 mm vs. 37.2 ± 2.1 mm, P = 0.016). Patients with Eustachian tube dysfunction have a high incidence of submucosal cleft palate and its occult variant, which are challenging to diagnose without any preexisting suspicion. Clinicians should evaluate the hard palate and vomer to exclude the presence of occult submucosal cleft palate while diagnosing Eustachian tube dysfunction., (© 2022. The Author(s).)

Ski-slope hearing loss (HL), which refers to increased auditory threshold at high frequencies, is common in adults. However, genetic contributions to this post-lingual HL remain largely unknown. Here, we prospectively investigated deafness-associated and novel candidate genes causing ski-slope HL. We analyzed 192 families with post-lingual HL via gene panel and/or exome sequencing. With an overall molecular diagnostic rate of 35.4% (68/192) in post-lingual HL, ski-slope HL showed a lower diagnostic rate (30.7%) compared with other conditions (40.7%). In patients who showed HL onset before the age of 40, genetic diagnostic probability was significantly lower for ski-slope HL than for other conditions. Further analysis of 51 genetically undiagnosed patients in the ski-slope HL group identified three variants in delta-like ligand 1 (DLL1), a Notch ligand, which presented in vitro gain-of-function effects on Notch downstream signaling. In conclusion, genetic diagnostic rates in post-lingual HL varied according to audiogram patterns with age-of-onset as a confounding factor. DLL1 was identified as a candidate gene causing ski-slope HL., (© 2021. The Author(s).)

This phenotype-genotype study aimed to investigate the extent of audioprofile variability related to cochlin major domains and to identify potential ethnic-specific differences associated with COCH-related hearing loss. Eight Korean families (26 cases) were diagnosed with COCH-related hearing loss by exome sequencing. Audiometric test results were combined with those from nine published East Asian families (20 cases) and compared with those from 38 European-descent families (277 cases). Audioprofiles were created by grouping audiometric test results into age ranges by age at testing and then averaging hearing loss thresholds by frequency within age ranges. The functional impact of the identified variants was assessed in vitro by examining the intracellular trafficking, secretion, and cleavage of cochlin. In both East Asian and European-descent families segregating COCH-related hearing loss, deafness-associated variants in non-LCCL domains of cochlin were associated with hearing loss that was more severe earlier in life than hearing loss caused by variants in the LCCL domain. Consistent with this phenotypic difference, functional studies demonstrated distinct pathogenic mechanisms for COCH variants in a domain-dependent manner; specifically, a cytotoxic effect was observed for the p.Phe230Leu variant, which is located in the vWFA1 domain. No ethnic-specific differences in hearing loss progression were observed, except for those attributable to an overrepresentation of presymptomatic cases in the European-descent cohort., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: COVID-19 often causes respiratory symptoms, making otolaryngology offices one of the most susceptible places for community transmission of the virus. Thus, telemedicine may benefit both patients and physicians., Objective: This study aims to explore the feasibility of telemedicine for the diagnosis of all otologic disease types., Methods: A total of 177 patients were prospectively enrolled, and the patient's clinical manifestations with otoendoscopic images were written in the electrical medical records. Asynchronous diagnoses were made for each patient to assess Top-1 and Top-2 accuracy, and we selected 20 cases to conduct a survey among four different otolaryngologists to assess the accuracy, interrater agreement, and diagnostic speed. We also constructed an experimental automated diagnosis system and assessed Top-1 accuracy and diagnostic speed., Results: Asynchronous diagnosis showed Top-1 and Top-2 accuracies of 77.40% and 86.44%, respectively. In the selected 20 cases, the Top-2 accuracy of the four otolaryngologists was on average 91.25% (SD 7.50%), with an almost perfect agreement between them (Cohen kappa=0.91). The automated diagnostic model system showed 69.50% Top-1 accuracy. Otolaryngologists could diagnose an average of 1.55 (SD 0.48) patients per minute, while the machine learning model was capable of diagnosing on average 667.90 (SD 8.3) patients per minute., Conclusions: Asynchronous telemedicine in otology is feasible owing to the reasonable Top-2 accuracy when assessed by experienced otolaryngologists. Moreover, enhanced diagnostic speed while sustaining the accuracy shows the possibility of optimizing medical resources to provide expertise in areas short of physicians., (©Dongchul Cha, Seung Ho Shin, Jungghi Kim, Tae Seong Eo, Gina Na, Seonghoon Bae, Jinsei Jung, Sung Huhn Kim, In Seok Moon, Jaeyoung Choi, Yu Rang Park. Originally published in JMIR Medical Informatics (http://medinform.jmir.org), 19.10.2020.)

Many anion channels, frequently referred as Cl - channels, are permeable to different anions in addition to Cl - . As the second-most abundant anion in the human body, HCO 3 - permeation via anion channels has many important physiological roles. In addition to its classical role as an intracellular pH regulator, HCO 3 - also controls the activity and stability of dissolved proteins in bodily fluids such as saliva, pancreatic juice, intestinal fluid, and airway surface liquid. Moreover, HCO 3 - permeation through these channels affects membrane potentials that are the driving forces for transmembrane transport of solutes and water in epithelia and affect neuronal excitability in nervous tissue. Consequently, aberrant HCO 3 - transport via anion channels causes a number of human diseases in respiratory, gastrointestinal, genitourinary, and neuronal systems. Notably, recent studies have shown that the HCO 3 - permeabilities of several anion channels are not fixed and can be altered by cellular stimuli, findings which may have both physiological and pathophysiological significance. In this review, we summarize recent progress in understanding the molecular mechanisms and the physiological roles of HCO 3 - permeation through anion channels. We hope that the present discussions can stimulate further research into this very important topic, which will provide the basis for human disorders associated with aberrant HCO 3 - transport.

Outer hair cells (OHCs) play an essential role in hearing by acting as a nonlinear amplifier which helps the cochlea detect sounds with high sensitivity and accuracy. This nonlinear sound processing generates distortion products, which can be measured as distortion-product otoacoustic emissions (DPOAEs). The OHC stereocilia that respond to sound vibrations are connected by three kinds of extracellular links: tip links that connect the taller stereocilia to shorter ones and convey force to the mechanoelectrical transduction channels, tectorial membrane-attachment crowns (TM-ACs) that connect the tallest stereocilia to one another and to the overlying TM, and horizontal top connectors (HTCs) that link adjacent stereocilia. While the tip links have been extensively studied, the roles that the other two types of links play in hearing are much less clear, largely because of a lack of suitable animal models. Here, while analyzing genetic combinations of tubby mice, we encountered models missing both HTCs and TM-ACs or HTCs alone. We found that the tubby mutation causes loss of both HTCs and TM-ACs due to a mislocalization of stereocilin, which results in OHC dysfunction leading to severe hearing loss. Intriguingly, the addition of the modifier allele modifier of tubby hearing 1 in tubby mice selectively rescues the TM-ACs but not the HTCs. Hearing is significantly rescued in these mice with robust DPOAE production, indicating an essential role of the TM-ACs but not the HTCs in normal OHC function. In contrast, the HTCs are required for the resistance of hearing to damage caused by noise stress., Competing Interests: The authors declare no competing interest.

Backgraoud & Aims: Aberrant epithelial bicarbonate (HCO 3 - ) secretion caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is associated with several diseases including cystic fibrosis and pancreatitis. Dynamically regulated ion channel activity and anion selectivity of CFTR by kinases sensitive to intracellular chloride concentration ([Cl - ] i ) play an important role in epithelial HCO 3 - secretion. However, the molecular mechanisms of how [Cl - ] i -dependent mechanisms regulate CFTR are unknown., Methods: We examined the mechanisms of the CFTR HCO 3 - channel regulation by [Cl - ] i -sensitive kinases using an integrated electrophysiological, molecular, and computational approach including whole-cell, outside-out, and inside-out patch clamp recordings and molecular dissection of WNK1 and CFTR proteins. In addition, we analyzed the effects of pancreatitis-causing CFTR mutations on the WNK1-mediated regulation of CFTR., Results: Among the WNK1, SPAK, and OSR1 kinases that constitute a [Cl - ] i -sensitive kinase cascade, the expression of WNK1 alone was sufficient to increase the CFTR bicarbonate permeability (P HCO3 /P Cl ) and conductance (G HCO3 ) in patch clamp recordings. Molecular dissection of the WNK1 domains revealed that the WNK1 kinase domain is responsible for CFTR P HCO3 /P Cl regulation by direct association with CFTR, while the surrounding N-terminal regions mediate the [Cl - ] i -sensitivity of WNK1. Furthermore, the pancreatitis-causing R74Q and R75Q mutations in the elbow helix 1 of CFTR hampered WNK1-CFTR physical associations and reduced WNK1-mediated CFTR P HCO3 /P Cl regulation., Conclusion: The CFTR HCO 3 - channel activity is regulated by [Cl - ] i and a WNK1-dependent mechanism. Our results provide new insights into the regulation of the ion selectivity of CFTR and the pathogenesis of CFTR-related disorders., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Late-onset, down-sloping sensorineural hearing loss has many genetic and nongenetic etiologies, but the proportion of this commonly encountered type of hearing loss attributable to genetic causes is not well known. In this study, the authors performed genetic analysis using next-generation sequencing techniques in patients showing late-onset, down-sloping sensorineural hearing loss with preserved low-frequency hearing, and investigated the clinical implications of the variants identified., Design: From a cohort of patients with hearing loss at a tertiary referral hospital, 18 unrelated probands with down-sloping sensorineural hearing loss of late onset were included in this study. Down-sloping hearing loss was defined as a mean low-frequency threshold at 250 Hz and 500 Hz less than or equal to 40 dB HL and a mean high-frequency threshold at 1, 2, and 4 kHz greater than 40 dB HL. The authors performed whole-exome sequencing and segregation analysis to identify the genetic causes and evaluated the outcomes of auditory rehabilitation in the patients., Results: There were nine simplex and nine multiplex families included, in which the causative variants were found in six of 18 probands, demonstrating a detection rate of 33.3%. Various types of variants, including five novel and three known variants, were detected in the MYH14, MYH9, USH2A, COL11A2, and TMPRSS3 genes. The outcome of cochlear and middle ear implants in patients identified with pathogenic variants was satisfactory. There was no statistically significant difference between pathogenic variant-positive and pathogenic variant-negative groups in terms of onset age, family history of hearing loss, pure-tone threshold, or speech discrimination scores., Conclusions: The proportion of patients with late-onset, down-sloping hearing loss identified with potentially causative variants was unexpectedly high. Identification of the causative variants will offer insights on hearing loss progression and prognosis regarding various modes of auditory rehabilitation, as well as possible concomitant syndromic features.

Objective: To investigate differences in the clinical features of bilateral Menière's disease (BMD) with early and late bilateral involvement., Study Design: A retrospective case-comparison study., Setting: Tertiary referral center., Patients: In total, 25 patients with definite BMD were enrolled. Patients with bilateral involvement with a transition interval shorter than 1 month were considered to have synchronous BMD, whereas the others had metachronous BMD., Interventions: We investigated differences in prognosis as defined by changes in the number of vertigo attacks after treatment, demographics, comorbidities, and inner ear function according to the transition interval from unilateral to bilateral involvement., Main Outcome Measure: We investigated other appropriate cut-off values in the interval from first- to second-ear involvement to predict poor prognosis., Results: Receiver operating characteristic curve analysis revealed that a cut-off value of < 18-month interval exhibited maximum sensitivity and specificity for predicting poor prognosis. According to this value, we categorized patients into the early bilateral involvement group (EBIG, < 18 months' interval) and the late bilateral involvement group (LBIG, ≥ 18 months' interval). Patients with synchronous BMD and patients in the EBIG group exhibited poorer prognosis compared with patients with metachronous BMD and those in LBIG (p = 0.011 and p ≤ 0.001). Demographics, hearing threshold, vestibular deficit, and comorbidities were not significantly different between the two groups (p > 0.05). None of the patients exhibited systemic autoimmune disease., Conclusion: BMD with early bilateral progression exhibited poorer prognosis compared with late bilateral progression.

The His723Arg (H723R) mutation in SLC26A4 , encoding pendrin, is the most prevalent mutation in East Asia, resulting in DFNB4, an autosomal recessive type of genetic hearing loss. Although the main pathological mechanism of H723R was identified as a protein-folding defect in pendrin, there is still no curative treatment for associated hearing loss. Here, we show that H723R-pendrin expression and activity are rescued by activation of the chaperonin DNAJC14. In vitro , DNAJC14 was activated via Japanese encephalitis virus (JEV) inoculation, and toxin-attenuated JEV rescued the surface expression and anion exchange activity of H723R-pendrin. Human H723R-pendrin transgenic mice (hH723R Tg) were established in a mouse slc26a4 knockout background, in which only hH723R-pendrin was expressed in the inner ear (Pax2-Cre dependent) to mimic human DFNB4 pathology. Crossing hH723R Tg with DNAJC14-overexpressing mice resulted in reduced cochlear hydrops and more preserved outer hair cells in the cochlea compared to those in hH723R Tg mice. Furthermore, the stria vascularis and spiral ligament were thicker and KCNJ10 expression was increased with DNAJC14 overexpression; however, hearing function and enlarged endolymphatic hydrops were not recovered. These results indicate that DNAJC14 overexpression ameliorates the cochlear degeneration caused by misfolded pendrin and might be a potential therapeutic target for DFNB4., (© 2019 The Authors.)

Objective: To evaluate the clinical feasibility and auditory benefits of hearing rehabilitation using electroacoustic stimulation (EAS) after cochlear implantation (CI) and to identify the predictive factors for successful EAS rehabilitation in children with limited low-frequency hearing., Study Design: Retrospective case review., Setting: Tertiary referral hospital., Patients: Seventeen children (21 ears) under the age of 15 years with residual low-frequency hearing who underwent CI using hearing preservation techniques., Intervention: Patients underwent CI using hearing preservation techniques, and the postoperative audiograms were obtained to evaluate the hearing preservation rate. EAS rehabilitation was applied in patients with successful low-frequency hearing preservation., Outcome Measures: Improvements in speech perception in both quiet and noise conditions were compared between the EAS mode and the CI-only mode. The predictive factors for successful EAS rehabilitation in children were analyzed., Results: Functional low-frequency residual hearing less than or equal to 85 dB at 250 and 500 Hz was achieved postoperatively in six of 21 ears, and successful EAS rehabilitation was possible in nine of 21 ears. Better speech perception scores were observed in quiet conditions using the EAS mode compared with the CI-only mode, although the difference did not reach statistical significance. Significantly, better scores were observed in noise conditions with the EAS mode compared with the CI-only mode. Postoperative low-frequency pure-tone average was the only significant predictive factor of successful EAS rehabilitation., Conclusion: CI surgery using hearing preservation techniques with EAS rehabilitation should be performed in children, even in patients with limited residual hearing, to improve auditory outcomes.

Objectives: The aims of the study are to identify the limitations of the current newborn hearing screening (NHS) programs and provide recommendations for better protocols., Study Design: Retrospective analysis., Setting: Tertiary referral center., Patients: The study participants were 185 children who received cochlear implants (CIs) at ≤5 years of age., Interventions: Therapeutic and rehabilitative., Main Outcome Measures: The results of NHS, screening tools used, age, and hearing thresholds at which hearing loss was confirmed, causes of the hearing loss, age of CI insertion, aided pure-tone audiogram findings, and language development level were analyzed., Results: NHS data was available for 109 children, and 24 patients (22.0%) had passed NHS for both ears. Hearing loss was confirmed considerably later in children who had passed NHS than in children who were referred for further evaluation (p < 0.01). The most common cause for hearing loss in the NHS-pass group was SLC26A4 mutations (41.7%). Patients in the NHS-pass group received CIs considerably later than those in the NHS-referred group (p < 0.01). Among patients with SLC26A4 mutations, the language development level was significantly lower in the NHS-pass group than in the NHS-referred group (p < 0.01)., Conclusions: Careful counseling regarding NHS results is necessary for parents to understand that the absence of hearing loss at birth does not mean that the child will not develop hearing loss later in life. Genetic testing for SLC26A4 mutations may be necessary in regions with a high incidence of these mutations, such as East Asia.

Objective: Delayed facial palsy has been reported following various types of otologic surgery. However, the exact characteristics of this disease have not been fully elucidated because of its low incidence. This study analyzed case series studies on delayed facial palsy to increase the sample size and outline credible disease characteristics., Data Sources: PubMed, Embase, and Cochrane Library databases were searched on October 10, 2018., Study Selection: Delayed facial palsy case series covered in English in which the intervention was typical tympanoplasty, mastoidectomy, stapedectomy, or cochlear implantation including a statement of sample size., Data Extraction: Evaluated according to the Joanna Briggs Institute Critical Appraisal Checklist for Case Series., Data Synthesis: Fourteen case series studies were included. Incidence rate, onset time, prognosis were evaluated with meta-analysis. Etiology and treatment were discussed with systematic review., Conclusions: The overall incidence rate of delayed facial palsy after middle ear surgery was 0.65%; however, it differed depending on the type of surgery. The mean onset time of facial palsy was 8.47 ± 3.98 days after surgery, and 95.3% of the patients completely recovered. The disease seems to have multiple etiologies. Facial palsy occurring 2 to 20 days after surgery is suggested to be considered delayed facial palsy.

KCNQ4 is frequently mutated in autosomal dominant non-syndromic hearing loss (NSHL), a typically late-onset, initially high-frequency loss that progresses over time (DFNA2). Most KCNQ4 mutations linked to hearing loss are clustered around the pore region of the protein and lead to loss of KCNQ4-mediated potassium currents. To understand the contribution of KCNQ4 variants to NSHL, we surveyed public databases and found 17 loss-of-function and six missense KCNQ4 variants affecting amino acids around the pore region. The missense variants have not been reported as pathogenic and are present at a low frequency (minor allele frequency < 0.0005) in the population. We examined the functional impact of these variants, which, interestingly, induced a reduction in potassium channel activity without altering expression or trafficking of the channel protein, being functionally similar to DFNA2-associated KCNQ4 mutations. Therefore, these variants may be risk factors for late-onset hearing loss, and individuals harboring any one of these variants may develop hearing loss during adulthood. Reduced channel activity could be rescued by KCNQ activators, suggesting the possibility of medical intervention. These findings indicate that KCNQ4 variants may contribute more to late-onset NSHL than expected, and therefore, genetic screening for this gene is important for the prevention and treatment of NSHL.

In the inner ear, endolymph fluid surrounds the organ of Corti, which is important for auditory function; notably, even slight environmental changes mediated by trauma or infection can have significant consequences. However, it is unclear how the immune response is modulated in these tissues. Here, we report the local immune surveillance role of cleaved cochlin LCCL (Limulus factor C, Cochlin, and Lgl1) during Pseudomonas aeruginosa infection in the cochlea. Upon infection, the LCCL domain is cleaved from cochlin and secreted into the perilymph. This cleaved fragment sequesters infiltrating bacteria in the scala tympani and subsequently recruits resident immune cells to eliminate the bacteria. Importantly, hearing loss in a cochlin knockout mouse model is remedied by treatment with a cochlin LCCL peptide. These findings suggest cleaved cochlin LCCL constitutes a critical factor in innate immunity and auditory function and may be a potential therapeutic target to treat chronic otitis media-induced hearing loss., (Copyright © 2019 Elsevier Inc. All rights reserved.)

As the number of genes identified for linkage to hearing loss has been increasing and more public databases have become available, we aimed to systematically evaluate all variants reported for nonsyndromic hearing loss (NSHL) based on their allele frequencies (AFs) in the general population. Among the 3,549 variants in 97 NSHL genes reported as pathogenic/likely pathogenic in ClinVar and HGMD, 1,618 were found in public databases (gnomAD, ExAC, EVS, and 1000G). To evaluate the pathogenicity of these variants, we employed AF thresholds and NSHL-optimized ACMG guidelines. AF thresholds were determined using a high-resolution variant frequency framework and Hardy-Weinberg equilibrium calculation: 0.6% and 0.1% for recessive and dominant genes, respectively. Filtering AFs of variants linked to NSHL were obtained based on AFs reported in gnomAD and ExAC. We found that 48 variants in 23 genes had filtering AFs above the suggested thresholds and assumed that these variants might be benign based on their filtering AFs. 47 variants, except for one notorious high-frequency GJB2 mutation (c.109G > A; p.Val37Ile), were confirmed to be benign/likely benign by the NSHL-optimized ACMG guidelines. The proposed systematic approach will aid in precise evaluation of NSHL variant pathogenicity in the context of filtering AFs, AF thresholds, and NSHL-specific ACMG guidelines, thus improving NSHL diagnostics.

OTOG was identified as a nonsyndrmoic hearing loss gene in 2012 in two families with nonprogressive mild-to-moderate hearing loss. However, no further literature have this gene for nonsyndromic hearing loss. Furthermore, it is still unclear whether vestibular impairment is involved or not in patients with mutations in OTOG. This study presents a validated second report for homozygous causative mutations in OTOG of mild hearing loss. Whole exome sequencing (WES) was performed in a five-year-old male proband with mild hearing loss. The analysis of WES revealed a homozygous truncating mutation (c.330C > G; p.Tyr110*) in OTOG. The identified novel mutation, p.Tyr110*, leads to a null allele based on the fact that early truncated protein contains no functional domain of otogelin. While defects in otogelin previously reported to result in hearing loss and vestibular dysfunction, p.Tyr110* only caused nonsydromic and nonprogressive hearing loss without any vestibular impairment, indicating that vestibular phenotype would be variable. Given that mild hearing loss is not easy to be detected early, mutations of OTOG may be more prevalent than reported. Therefore, genetic evaluation for OTOG should be considered in children with mild hearing loss with/without vestibular dysfunction., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

The endolymphatic sac (ES) is a cystic structure of the inner ear connected to the cochlea and vestibule, which plays a role in regulating ion homeostasis in inner ear fluid. Disruption of ion homeostasis can cause inner ear disorders with hearing loss and dizziness, such as Meniere's disease. Herein, we found, for the first time, functional evidence for the involvement of β 1 - and β 2 -adrenergic receptors in apical electrogenic ion transport by human ES epithelium by using electrophysiological/pharmacological and molecular biological methods, which were dependent on K + and Cl - ion transport. The apical electrogenic transport was absent or very weak in ES epithelia of patients with Meniere's disease. These results suggested that adrenergic stimulation via β 1 - and β 2 -adrenergic receptors in the human ES was involved in regulation of inner ear fluid ion homeostasis and impairment of this response could be a pathological mechanism of Meniere's disease., Competing Interests: The authors declare no competing financial interests.

The endolymphatic sac (ES) is a cystic organ that is a part of the inner ear and is connected to the cochlea and vestibule. The ES is thought to be involved in inner ear ion homeostasis and fluid volume regulation for the maintenance of hearing and balance function. Many ion channels, transporters, and exchangers have been identified in the ES luminal epithelium, mainly in animal studies, but there has been no functional study investigating ion transport using human ES tissue. We designed the first functional experiments on electrogenic transport in human ES and investigated the contribution of K(+) channels in the electrogenic transport, which has been rarely identified, even in animal studies, using electrophysiological/pharmacological and molecular biological methods. As a result, we identified functional and molecular evidence for the essential participation of K(+) channels in the electrogenic transport of human ES epithelium. The identified K(+) channels involved in the electrogenic transport were KCNN2, KCNJ14, KCNK2, and KCNK6, and the K(+) transports via those channels are thought to play an important role in the maintenance of the unique ionic milieu of the inner ear fluid.

Transepithelial bicarbonate secretion plays a key role in the maintenance of fluid and protein secretion from epithelial cells and the protection of the epithelial cell surface from various pathogens. Epithelial bicarbonate secretion is mainly under the control of cAMP and calcium signaling. While the physiological roles and molecular mechanisms of cAMP-induced bicarbonate secretion are relatively well defined, those induced by calcium signaling remain poorly understood in most epithelia. The present review summarizes the current status of knowledge on the role of calcium signaling in epithelial bicarbonate secretion. Specifically, this review introduces how cytosolic calcium signaling can increase bicarbonate secretion by regulating membrane transport proteins and how it synergizes with cAMP-induced mechanisms in epithelial cells. In addition, tissue-specific variations in the pancreas, salivary glands, intestines, bile ducts, and airways are discussed. We hope that the present report will stimulate further research into this important topic. These studies will provide the basis for future medicines for a wide spectrum of epithelial disorders including cystic fibrosis, Sjögren's syndrome, and chronic pancreatitis., (Copyright © 2014 Elsevier Ltd. All rights reserved.)