CRISPR/Cas9-mediated exon skipping to restore premature translation termination in a DFNB4 mouse model.

SLC26A4 encodes pendrin, a crucial anion exchanger essential for maintaining hearing function. Mutations in SLC26A4, including the prevalent c.919-2 A > G splice-site mutation among East Asian individuals, can disrupt inner ear electrolyte balance, leading to syndromic and non-syndromic hearing loss, such as Pendred syndrome and DFNB4. To explore potential therapeutic strategies, we utilized CRISPR/Cas9-mediated exon skipping to create a Slc26a4∆E8+E9/∆E8+E9 mouse model. We assessed pendrin expression in the inner ear and evaluated vestibular and auditory functions. The Slc26a4∆E8+E9/∆E8+E9 mice demonstrated reframed pendrin in the inner ear and normal vestibular functions, contrasting with severely abnormal vestibular functions observed in the Slc26a4 c.919-2 A > G splicing mutation mouse model. However, despite these molecular achievements, hearing function did not show the expected improvement, consistent with observed pathology, including cochlear hair cell loss and elevated hearing thresholds. Consequently, our findings highlight the necessity for alternative genetic editing strategies to address hearing loss caused by the SLC26A4 c.919-2 A > G mutation.

Hearing Features and Cochlear Implantation Outcomes in Patients With Pathogenic MYO15A Variants: a Multicenter Observational Study.

OBJECTIVES: Recessive variants in the MYO15A gene constitute an important cause of sensorineural hearing impairment (SNHI). However, the clinical features of MYO15A-related SNHI have not been systemically investigated. This study aimed to delineate the hearing features and outcomes in patients with pathogenic MYO15A variants. DESIGN: This study recruited 40 patients with biallelic MYO15A variants from 31 unrelated families. The patients were grouped based on the presence of N-terminal domain variants (N variants). The longitudinal audiological data and for those undergoing cochlear implantation, the auditory and speech performance with cochlear implants, were ascertained and compared between patients with different genotypes. RESULTS: At the first audiometric examination, 32 patients (80.0%) presented with severe to profound SNHI. Patients with at least one allele of the N variant exhibited significantly better hearing levels than those with biallelic non-N variants (78.2 ± 23.9 dBHL and 94.7 ± 22.8 dBHL, respectively) (p = 0.033). Progressive SNHI was observed in 82.4% of patients with non-profound SNHI, in whom the average progression rate of hearing loss was 6.3 ± 4.8 dBHL/year irrespective of the genotypes. Most of the 25 patients who underwent cochlear implantation exhibited favorable auditory and speech performances post-implantation. CONCLUSIONS: The hearing features of patients with biallelic pathogenic MYO15A variants are characterized by severe to profound SNHI, rapid hearing progression, and favorable outcomes with cochlear implants. Periodic auditory monitoring is warranted for these patients to enable early intervention.

Evaluating auditory brainstem response to a level-dependent chirp designed based on derived-band latencies.

The best cochlear-neural delay model for designing a chirp that can produce the largest auditory brainstem response (ABR) has not been established. This study comprised two experiments. Experiment I aimed to estimate the delay model by measuring derived-band ABR latencies at different levels. The results demonstrated that, as the level decreased, the delay between the center frequencies of 0.7 and 5.7 kHz increased. The aim of experiment II was to compare ABRs generated by three stimuli: (1) a level-dependent derived-band (DB)-Chirp, designed based on the model in experiment I; (2) a level-dependent level specific (LS)-Chirp from Kristensen and Elberling [(2012). J. Am. Acad. Audiol. 23, 712-721]; and (3) a click. The results demonstrated that the DB-Chirp produced significantly larger wave V than the LS-Chirp at 45 dB normal hearing level (nHL); however, no differences were observed at other levels. The wave I generated by the DB-Chirp and LS-Chirp were significantly larger than those evoked by the click at 45 and 60 dB nHL and at 30 and 45 dB nHL, respectively; however, at all levels, no differences between these two chirps were observed. The DB-Chirp may be a valuable stimulus for producing ABRs for clinical applications such as assessing cochlear synaptopathy and estimating hearing sensitivity.

Association of hearing loss with land transport accidents: a nationwide population-based study.

OBJECTIVE: This study aimed to investigate the association of prior hearing loss with land transport accidents using a nationwide population-based dataset. DESIGN: A case-control study. STUDY SAMPLE: Data for this study were obtained from Taiwan's National Health Insurance Dataset. We retrieved data on 2066 patients who had received a diagnosis of a land transport accident as cases. We used a propensity score-matched method to select 6198 controls. RESULTS: A Chi-squared test revealed that there was a significant difference in the prevalence of prior hearing loss between cases and controls (6.8% vs. 5.6%, p = 0.046). The odds ratio (OR) of prior hearing loss for cases was 1.128 (95% confidence interval [CI]: 1.003 ∼ 1.503) compared to controls. After adjusting for demographic variables and comorbidities, the OR of hearing loss for cases was 1.238 (95% CI: 1.008 ∼ 1.522) that of controls. CONCLUSIONS: Our finding suggests that pre-existing hearing loss may be associated with land transport accidents among adults aged 50 years and older. Further study is needed to elucidate the mechanism(s) through which hearing loss may contribute to land transport accidents and examine how the use of hearing rehabilitation devices, for example, hearing aids impacts the observed associations.

Objective Signal Analysis for Investigating Feasibility of Active Noise Cancellation in Hearing Screening.

With the development of active noise cancellation (ANC) technology, ANC has been used to mitigate the effects of environmental noise on audiometric results. However, objective evaluation methods supporting the accuracy of audiometry for ANC exposure to different levels of noise have not been reported. Accordingly, the audio characteristics of three different ANC headphone models were quantified under different noise conditions and the feasibility of ANC in noisy environments was investigated. Steady (pink noise) and non-steady noise (cafeteria babble noise) were used to simulate noisy environments. We compared the integrity of pure-tone signals obtained from three different ANC headphone models after processing under different noise scenarios and analyzed the degree of ANC signal correlation based on the Pearson correlation coefficient compared to pure-tone signals in quiet. The objective signal correlation results were compared with audiometric screening results to confirm the correspondence. Results revealed that ANC helped mitigate the effects of environmental noise on the measured signal and the combined ANC headset model retained the highest signal integrity. The degree of signal correlation was used as a confidence indicator for the accuracy of hearing screening in noise results. It was found that the ANC technique can be further improved for more complex noisy environments.

Ten-year trends in the incidence of microtia: a nationwide population-based study from Taiwan.

PURPOSE: Few studies have explored population-based incidence rates of microtia using nationwide data. The aim of this study was to analyze the 10-year secular trends in the incidence of microtia and/or anotia in Taiwan from 2008 to 2017 using nationwide population-based data. METHODS: Patient data were retrieved from Taiwan's National Health Insurance Dataset, after identifying 1152 children aged ≤ 1 year with a first-time diagnosis of microtia or anotia between January 2008 and December 2017. The annual microtia-anotia incidence rate was the sum of new microtia-anotia cases in a year divided by total infant population in the year. Furthermore, we used the annual percent change (APC) to study the secular trend in microtia-anotia incidence rate. RESULTS: The annual incidence rate of microtia-anotia averaged across the 10-year period was 57.7 per 100,000 infants (standard deviation = 8.6). The annual incidence rates of microtia and anotia were 53.3 and 4.4 per 100,000 infants, respectively, during this period. Furthermore, female infants had a higher incidence than males (63.3 vs. 52.4 per 100,000). The incidence of microtia-anotia gradually decreased between 2008 and 2017 with an APC of - 5.64% (95% CI - 9.31 ~ - 1.18%, p = 0.004). Since 2011, females had a significantly higher annual incidence rate of microtia-anotia than males. CONCLUSIONS: The incidence of microtia-anotia was 57.7 per 100,000 infants in Taiwan, which declined during the study period 2008-2017. The female-to-male incidence ratio was 1.21:1.

A population-based case-control study of the association between cervical spondylosis and tinnitus.

OBJECTIVE: This population-based study aimed to study the association between tinnitus and cervical spondylosis. DESIGN: A case-control study. STUDY SAMPLE: We retrieved data from the Taiwan Longitudinal Health Insurance Database. We identified 2465 patients with tinnitus (cases) and 7395 comparison patients by propensity score matching. Multivariable logistic regressions were conducted to estimate the odds (OR) of a diagnosis of cervical spondylosis preceding the tinnitus diagnosis relative to controls. RESULTS: We found that 1596 (16.19%) of 9860 sample patients had received a diagnosis of cervical spondylosis before the index date, significantly different between the tinnitus group and control group (17.20% vs. 15.85%, p < 0.001). Logistic regression analysis showed an adjusted OR for prior cervical spondylosis of 1.235 for cases vs. controls (95% confidence interval [CI]: 1.088-1.402). Further, the adjusted ORs were 1.246 (95% CI: 1.041-1.491) and 1.356 (95% CI: 1.016-1.811), respectively, among patients aged 45 ∼ 64 and >64 groups. No difference in cervical spondylosis likelihood between cases and controls was found among patients aged 18 ∼ 44 groups. CONCLUSIONS: In conclusion, the study shows a positive association between cervical spondylosis and tinnitus. The findings call for greater awareness among physicians about a possible somatosensory component of cervical spine function which may contribute to tinnitus.

Toward the Pathogenicity of the SLC26A4 p.C565Y Variant Using a Genetically Driven Mouse Model.

Recessive variants of the SLC26A4 gene are globally a common cause of hearing impairment. In the past, cell lines and transgenic mice were widely used to investigate the pathogenicity associated with SLC26A4 variants. However, discrepancies in pathogenicity between humans and cell lines or transgenic mice were documented for some SLC26A4 variants. For instance, the p.C565Y variant, which was reported to be pathogenic in humans, did not exhibit functional pathogenic consequences in cell lines. To address the pathogenicity of p.C565Y, we used a genotype-based approach in which we generated knock-in mice that were heterozygous (Slc26a4+/C565Y), homozygous (Slc26a4C565Y/C565Y), and compound heterozygous (Slc26a4919-2A>G/C565Y) for this variant. Subsequent phenotypic characterization revealed that mice with these genotypes demonstrated normal auditory and vestibular functions, and normal inner-ear morphology and pendrin expression. These findings indicate that the p.C565Y variant is nonpathogenic for mice, and that a single p.C565Y allele is sufficient to maintain normal inner-ear physiology in mice. Our results highlight the differences in pathogenicity associated with certain SLC26A4 variants between transgenic mice and humans, which should be considered when interpreting the results of animal studies for SLC26A4-related deafness.

Generation and pathological characterization of a transgenic mouse model carrying a missense PJVK mutation.

Hearing loss is the most prevalent hereditary sensory disorder in children. Approximately 2 in 1000 infants are affected by genetic hearing loss. The PJVK gene, which encodes the pejvakin protein, has been linked to autosomal recessive non-syndromic hearing loss DFNB59. Previous clinical studies have revealed that PJVK mutations might be associated with a wide spectrum of auditory manifestations, ranging from hearing loss of pure cochlear origin to that involving the retrocochlear central auditory pathway. The phenotypic variety makes the pathogenesis of this disease difficult to determine. Similarly, mouse models carrying different Pjvk defects show phenotypic variability and inconsistency. In this study, we generated a knockin mouse model carrying the c.874G > A (p.G292R) variant to model and investigate the auditory and vestibular phenotypes of DFNB59.

Increased risk of tinnitus following a trigeminal neuralgia diagnosis: a one-year follow-up study.

BACKGROUND: Tinnitus due to hyperactivity across neuronal ensembles along the auditory pathway is reported. We hypothesized that trigeminal neuralgia patients may subsequently suffer from tinnitus. Using nationwide, population-based data and a retrospective cohort study design, we investigated the risk of tinnitus within 1 year following trigeminal neuralgia. METHODS: We used the Taiwan National Health Insurance Research Dataset, a claims database, to identify all patients diagnosed with trigeminal neuralgia from January 2001 to December 2014, 12,587 patients. From the remaining patients, we identified 12,587 comparison patients without trigeminal neuralgia by propensity score matching, using sex, age, monthly income, geographic region, residential urbanization level, and tinnitus-relevant comorbidities (hyperlipidemia, diabetes, coronary heart disease, hypertension, cervical spondylosis, temporomandibular joint disorders and injury to head and neck and index year). All study patients (n = 25,174) were tracked for a one-year period to identify those with a subsequent diagnosis of tinnitus over 1-year follow-up. RESULTS: Among total 25,174 sample patients, the incidence of tinnitus was 18.21 per 100 person-years (95% CI = 17.66 ~ 18.77), the rate being 23.57 (95% CI = 22.68 ~ 24.49) among patients with trigeminal neuralgia and 13.17 (95% CI = 12.53 ~ 13.84) among comparison patients. Furthermore, the adjusted Cox proportional hazard ratio for tinnitus in the trigeminal neuralgia group was 1.68 (95% CI = 1.58 ~ 1.80) relative to the comparison cohort. CONCLUSIONS: We found a significantly increased risk of tinnitus within 1 year of trigeminal neuralgia diagnosis compared to those without the diagnosis. Further studies in other countries and ethnicities are needed to explore the relationship between trigeminal neuralgia and subsequent tinnitus.

Correction to: Increased risk of tinnitus following a trigeminal neuralgia diagnosis: a one-year follow-up study.

An amendment to this paper has been published and can be accessed via the original article.

Increasing the expression level of ChR2 enhances the optogenetic excitability of cochlear neurons.

Optogenetics comprise a promising alternative to electrical stimulation for characterization of neural circuits and for the next generation of neural prostheses. Optogenetic stimulation relies on expression of photosensitive microbial proteins in animal cells to initiate a flow of ions into the cells in response to visible light. Here, we generated a novel transgenic mouse model in which we studied the optogenetic activation of spiral ganglion neurons, the primary afferent neurons of the auditory system, and showed a strong optogenetic response, with a similar amplitude as the acoustically evoked response. A twofold increase in the level of channelrhodopsin expression significantly increased the photosensitivity at both the single cell and organismal levels but also partially compromised the native electrophysiological properties of the neurons. The importance of channelrhodopsin expression level to optogenetic stimulation, revealed by these quantitative measurements, will be significant for the characterization of neural circuitry and for the use of optogenetics in neural prostheses.NEW & NOTEWORTHY This study reveals a dose-response relationship between channelrhodopsin expression and optogenetic excitation. Both single cell and organismal responses depend on the expression level of the heterologous protein. Expression level of the opsin is thus an important variable in determining the outcome of an optogenetic experiment. These results are key to the implementation of neural prostheses based on optogenetics, such as next generation cochlear implants, which would use light to elicit a neural response to sound.

Consensus interpretation of the p.Met34Thr and p.Val37Ile variants in GJB2 by the ClinGen Hearing Loss Expert Panel.

PURPOSE: Pathogenic variants in GJB2 are the most common cause of autosomal recessive sensorineural hearing loss. The classification of c.101T>C/p.Met34Thr and c.109G>A/p.Val37Ile in GJB2 are controversial. Therefore, an expert consensus is required for the interpretation of these two variants. METHODS: The ClinGen Hearing Loss Expert Panel collected published data and shared unpublished information from contributing laboratories and clinics regarding the two variants. Functional, computational, allelic, and segregation data were also obtained. Case-control statistical analyses were performed. RESULTS: The panel reviewed the synthesized information, and classified the p.Met34Thr and p.Val37Ile variants utilizing professional variant interpretation guidelines and professional judgment. We found that p.Met34Thr and p.Val37Ile are significantly overrepresented in hearing loss patients, compared with population controls. Individuals homozygous or compound heterozygous for p.Met34Thr or p.Val37Ile typically manifest mild to moderate hearing loss. Several other types of evidence also support pathogenic roles for these two variants. CONCLUSION: Resolving controversies in variant classification requires coordinated effort among a panel of international multi-institutional experts to share data, standardize classification guidelines, review evidence, and reach a consensus. We concluded that p.Met34Thr and p.Val37Ile variants in GJB2 are pathogenic for autosomal recessive nonsyndromic hearing loss with variable expressivity and incomplete penetrance.

A case-control study of the association between sialolithiasis and osteoporosis.

OBJECTIVE: The purpose of this study was to evaluate the association between osteoporosis and salivary gland stone using a population-based claims database. DESIGN: A case-control design. SETTING: Taiwan. PARTICIPANTS: We retrieved the sample for this case-control study from the Taiwan "Longitudinal Health Insurance Database 2005." All 557 patients aged 40 years or older with a diagnosis of sialolithiasis were cases, and 1671 matched controls (without sialolithiasis) were selected. SUBJECTS AND METHODS: We used the chi-square test to explore differences between cases and controls on socio-demographic characteristics. Furthermore, conditional logistic regressions were used to examine the association of sialolithiasis with previously diagnosed osteoporosis. RESULTS: Of 2228 sampled patients, 171 (7.68%) had ever been previously diagnosed with osteoporosis; 58 (10.41%) among cases and 113 (6.76%) among controls (P = 0.005). Conditional logistic regression analysis found that the odds ratio (OR) of prior osteoporosis for cases was 1.79 (95% confidence interval [CI]: 1.24-2.59, P = 0.002) relative to controls after adjusting for urbanisation and the selected medical co-morbidities. Furthermore, we found that among patients aged ≥65 years, the adjusted OR of prior osteoporosis for cases was 1.89 (95% CI = 1.02-3.51). No significant relationship was observed among patients aged <65 years old. CONCLUSION: This study demonstrates an association between sialolithiasis and osteoporosis. Although the finding warrants further investigation, the results call for more awareness of the possible concurrence of osteoporosis among physicians and patients with salivary gland stones.

Destabilization of Atoh1 by E3 Ubiquitin Ligase Huwe1 and Casein Kinase 1 Is Essential for Normal Sensory Hair Cell Development.

Proneural basic helix-loop-helix transcription factor, Atoh1, plays a key role in the development of sensory hair cells. We show here that the level of Atoh1 must be accurately controlled by degradation of the protein in addition to the regulation of Atoh1 gene expression to achieve normal cellular patterning during development of the cochlear sensory epithelium. The stability of Atoh1 was regulated by the ubiquitin proteasome system through the action of Huwe1, a HECT-domain, E3 ubiquitin ligase. An interaction between Huwe1 and Atoh1 could be visualized by a proximity ligation assay and was confirmed by co-immunoprecipitation and mass spectrometry. Transfer of a lysine 48-linked polyubiquitin chain to Atoh1 by Huwe1 could be demonstrated both in intact cells and in a cell-free system, and proteasome inhibition or Huwe1 silencing increased Atoh1 levels. The interaction with Huwe1 and polyubiquitylation were blocked by disruption of casein kinase 1 (CK1) activity, and mass spectrometry and mutational analysis identified serine 334 as an important phosphorylation site for Atoh1 ubiquitylation and subsequent degradation. Phosphorylation by CK1 thus targeted the protein for degradation. Development of an extra row of inner hair cells in the cochlea and an approximate doubling in the number of afferent synapses was observed after embryonic or early postnatal deletion of Huwe1 in cochlear-supporting cells, and hair cells died in the early postnatal period when Huwe1 was knocked out in the developing cochlea. These data indicate that the regulation of Atoh1 by the ubiquitin proteasome pathway is necessary for hair cell fate determination and survival.

Increased prevalence of peripheral vestibular disorder among patients with Fabry disease.

BACKGROUND: Although peripheral vestibular disorder is a non-fatal complication of Fabry disease, fatalities have been reported in some case reports and case series. To date, no studies have examined the relative risk of peripheral vestibular disorder in patients with Fabry disease compared to the general population without the condition. Due to the high prevalence of Fabry disease in East Asia and the potential shared pathogenic pathways between Fabry disease and vasculopathy, we conducted a study using a nationwide population-based dataset to compare the prevalence of peripheral vestibular disorder between patients with Fabry disease and matched comparison patients. METHODS: Data was sourced from Taiwan's Longitudinal Health Insurance Database 2010. this study consists of 11,668 sampled patients, 2917 study patients with Fabry disease and 8751 propensity-score-matching comparison patients. We conducted multiple logistic regression analysis to study the association between peripheral vestibular disorder and Fabry disease. RESULTS: The study identified notable differences in the prevalence of various vestibular disorders between the study and comparison groups. Specifically, there was a 7.2% increased prevalence of peripheral vestibular disorder in the study group (28.3%) compared to the comparison group (20.9%), Meniere's disease (5.4% vs. 3.7%), benign paroxysmal positional vertigo (5.1% vs. 3.3%), and other/ unspecified peripheral vestibular dizziness (15.6% vs. 11.8%) (all p < 0.001). The odds ratios for PVD, MD, BPPV, and other PVD were 1.44 (95% CI = 1.29-1.60), 1.50 (95% CI = 1.23-1.83), 1.59 (95% CI = 1.30-1.95), and 1.40 (95% CI = 1.24-1.58), respectively, among the Fabry disease group relative to the comparison group after adjusting for age, monthly income, geographic location, urbanization level, hyperlipidemia, diabetes, coronary heart disease, and hypertension. CONCLUSION: This study found that patients with Fabry disease had increased prevalence of peripheral vestibular disorder.

Association of Peripheral Vestibular Disorder with Diabetes: A Population-Based Study.

BACKGROUND: This study aimed to investigate the association of peripheral vestibular disorders with type 1 and type 2 diabetes using a population-based dataset. METHODS: The data for this study were obtained from Taiwan's Longitudinal Health Insurance Database 2010. The sample consisted of 150,916 patients who were newly diagnosed with peripheral vestibular disorders as cases and 452,748 propensity-score-matching controls without peripheral vestibular disorders. We utilized multivariate logistic regression models to quantitatively evaluate the association between peripheral vestibular disorders and diabetes while considering factors such as sex, age, geographic location, monthly income, urbanization level of the patient's residence, coronary heart disease, hypertension, and hyperlipidemia. RESULTS: The chi-squared test indicates that diabetes was more common in the peripheral vestibular disorder group compared to controls (20.6% vs. 15.1%, p < 0.001). Of all sampled patients, the adjusted odds ratio for diabetes was 1.597 (95% CI = 1.570~1.623) for those with peripheral vestibular disorders when compared to controls, while patients with Ménière's disease, benign paroxysmal positional vertigo, unilateral vestibulopathy, and other peripheral vestibular disorders had respective adjusted odds ratios of diabetes at 1.566 (95% CI = 1.498~1.638), 1.677 (95% CI = 1.603~1.755), 1.592 (95% CI = 1.504~1.685), and 1.588 (95% CI = l.555~1.621) in comparison to controls. CONCLUSIONS: Our research has revealed an association between diabetes and an increased susceptibility to peripheral vestibular disorders.

Association of Young-Onset Dementia with Pre-Existing Peripheral Vestibular Disorders.

Background: The relationship between young-onset dementia and peripheral vestibular disorders remained largely unknown although this association was observed in the older population. Objective: This case-control study aims to investigate the association of young-onset dementia with a pre-existing diagnosis of peripheral vestibular disorders using a population-based data from Taiwan's Longitudinal Health Insurance Database 2010. Methods: This study included 989 patients with young-onset dementia and 2967 propensity-score-matching controls. Differences in baseline characteristic between patients with young-onset dementia and controls were investigated using chi-square tests or t-tests. Multiple logistic regression models were employed to assess the association of young-onset dementia (outcome) with pre-existing peripheral vestibular disorders (predictor). Results: Compared to patients without young-onset dementia, those affected by this condition exhibited a statistically significantly higher rate of peripheral vestibular disorders (18.3% versus 8.2%, p < 0.001). Furthermore, our analysis found notable between-group disparities in the rates of Meniere's Disease (3.5% versus 2.0%, p= 0.015), benign paroxysmal positional vertigo (2.4% versus 1.1%, p= 0.006), and vestibular neuritis (2.4% versus 1.1%, p= 0.003). Multiple logistic regression analysis showed that the presence of prior peripheral vestibular disorders increased the odds of young-onset dementia [2.603 (95% CI = 2.105∼3.220)] after adjusting for age, sex, monthly income, geographic location, urbanization level, hyperlipidemia, diabetes, coronary heart disease, hearing loss, and hypertension. Conclusions: The study findings demonstrate a notable association between young-onset dementia and pre-existing peripheral vestibular disorders, suggesting that vestibular malfunction could play a role in the development of young-onset dementia.