Vision and hearing impairment are leading causes of disability, yet nationally representative data in Australia, particularly among Indigenous peoples, are scarce. The Australian Eye and Ear Health Survey aimed to estimate prevalence and risk factors of vision impairment and hearing impairment among Indigenous and non-Indigenous adults aged 50 years and older nationwide. This cross-sectional survey used stratified, multistage, random cluster sampling and was conducted across 30 sites in Australia. Stratification was done by geographical location and by Indigenous status to achieve national representativeness. Participants were systematically assessed for any vision impairment (presenting visual acuity <6/12 in the better eye), and any hearing impairment, and moderate or worse hearing impairment (pure tone average>25 decibels hearing level [dB HL], and >40 dB HL in the better ear), respectively. Door-to-door recruitment was the primary recruitment method. Crude and age-standardised prevalence estimates were calculated. Multivariable logistic regression models identified risk and protective factors. Between Aug 1, 2022, and March 31, 2025, a total of 4519 of 6128 eligible participants were recruited, of whom 617 (13·6%) participants were Indigenous (53·2% [328 participants] female vs 46·8% [289 participants] male; mean age 63·8 [SD 10·6] years) and 3902 (86·4%) participants were non-Indigenous (54·8% [2137 participants] female vs 45·2% [1765 participants] male; mean age 70·5 [9·8] years). The age-standardised prevalence of any vision impairment was 11·1% (95% CI 8·4-14·5) among Indigenous participants, 3·9% (3·3-4·6) among non-Indigenous participants, and 5·2% (4·5-6·0) overall. Any vision impairment was 2·9-times more prevalent among Indigenous than non-Indigenous Australians. The age-standardised prevalences of any hearing impairment, and moderate or worse hearing impairment were 42·8% (95% CI 36·8-49·5) and 14·3% (11·0-18·4) in Indigenous participants; 39·4% (37·3-41·8) and 13·2% (12·0-14·5) in non-Indigenous participants, and 41·7% (39·6-43·9) and 14·2% (13·1-15·5) overall, respectively. Among younger Indigenous participants, moderate or worse hearing impairment was almost three-fold higher than in similarly aged non-Indigenous participants (9·4% [95% CI 5·3-15·8] vs 3·2% [1·8-5·5] among individuals aged 50-59 years), and two-fold higher for Indigenous participants aged 60-69 years (14·3% [9·7-20·4] vs 6·9% [5·4-8·8]). Multivariable-adjusted risk factors in the whole sample were increasing age (both vision impairment and hearing impairment), having diabetes (both), current smoking (hearing impairment), and residence in remote locations (vision impairment). Protective factors were attainment of tertiary education (both), having private health insurance (both), attending an eye examination in the last 12 months (vision impairment), and female sex (hearing impairment). Indigenous status was associated with approximately two to three-fold greater risk of any vision impairment or hearing impairment in age-sex adjusted models, but this effect was no longer statistically significant after adjustment for other covariables. A substantial gap in vision impairment and, to a lesser extent, hearing impairment, persists between Indigenous and non-Indigenous Australians aged 50 years and older. Targeting shared modifiable risk factors and protective factors could reduce this inequity. Australian Government and Macquarie University.
Meniere's disease (MD) presents with vertigo and fluctuating auditory symptoms, linked to endolymphatic edema. Increased antidiuretic hormone levels due to stress suggest that hydration therapy (HT) can suppress this hormone. This study examined hearing outcomes in patients with MD treated with HT and factors influencing hearing fluctuations. The study included 188 participants (45 men and 143 women) with definite MD who were followed for over 4 years with HT (35 mL/kg water daily). Clinical characteristics, hearing thresholds, and hematological findings were analyzed. The average hearing threshold at low frequencies (125, 250, and 500 Hz) was measured at the first examination (pre-HT) and 4 years after HT (post-HT). Factors affecting pre-HT hearing thresholds, changes between pre-HT and post-HT, and factors influencing hearing changes during HT were investigated. Advanced age, male sex, disease duration, high creatinine level, low estimated glomerular filtration rate, and high white blood cell (WBC) counts correlated with poor hearing thresholds. No significant increase was observed in hearing thresholds between pre-HT and post-HT, with 70% showing stable or improved hearing after 4 years. Poor initial hearing threshold, high WBC count (P=.032), and high neutrophil count (P=.0090) were less likely to cause hearing deterioration. Hearing remained stable for over 4 years after HT. High WBC and neutrophil counts correlated with poor prognosis due to stress-related inflammation. Dehydration, elevated WBC counts, and stress may worsen outcomes, suggesting that HT effectively manages MD by stabilizing hearing and reducing stress.
Idiopathic sudden sensorineural hearing loss (ISSNHL) is an otologic emergency. While systemic corticosteroids are first-line therapy, intratympanic corticosteroid (ITC) injection has emerged as an important modality. The optimal timing of ITC-as primary therapy, combined initial treatment, or salvage therapy-remains controversial. To critically synthesize current evidence regarding ITC efficacy at different treatment timings and provide evidence-based clinical recommendations. A structured search of PubMed, Embase, and the Cochrane Library was conducted from database inception to December 2025 using terms sudden sensorineural hearing loss, ISSNHL, sudden deafness, intratympanic injection, ITC, intratympanic dexamethasone, and intratympanic methylprednisolone. The search identified 321 records, and additional articles were found in the reference lists of key reviews, meta-analyses, and guidelines. Studies were selected using predefined criteria, prioritizing randomized controlled trials, systematic reviews, meta-analyses, clinical practice guidelines, and relevant observational studies in adults with ISSNHL. Eligible studies evaluated ITC as primary monotherapy, combined initial therapy, or salvage therapy, and reported quantitative audiometric outcomes. Exclusion criteria included non-idiopathic sudden hearing loss, pediatric populations, non-corticosteroid intratympanic therapies, animal or laboratory-only studies, case reports, conference abstracts without full text, duplicate publications, and studies without clinically interpretable hearing outcomes. After screening, 25 studies were included. Salvage ITC provides significant benefit (OR: 6.04; 95% CI: 3.26-11.2; NNT≈3) with Grade A evidence. Combined initial therapy is superior to systemic steroids alone (OR: 2.50; 95% CI: 1.95-3.21), particularly for severe hearing loss. ITC monotherapy is non-inferior to systemic steroids (PTA difference: 2.0 dB). A stratified approach based on treatment timing is recommended. Salvage ITC should be offered to all patients with incomplete recovery. Combined therapy should be considered for patients with severe hearing loss. ITC monotherapy is appropriate when systemic steroids are contraindicated. İdiyopatik ani sensörinöral işitme kaybı (İASİK), acil müdahale gerektiren bir otolojik hastalıktır. Sistemik kortikosteroidler birinci basamak tedavi olarak kabul edilmekle birlikte, intratimpanik kortikosteroid (İTK) enjeksiyonu önemli bir tedavi seçeneği olarak öne çıkmıştır. Ancak İTK’nin primer tedavi, başlangıçta kombine tedavi veya kurtarma (salvage) tedavisi olarak uygulanması açısından en uygun zamanlama hâlen tartışmalıdır. Bu mini derlemenin amacı, İTK tedavisinin farklı uygulama zamanlarındaki etkinliğine ilişkin güncel kanıtları eleştirel biçimde sentezlemek ve kanıta dayalı klinik öneriler sunmaktır. PubMed, Embase ve Cochrane Library veri tabanlarında başlangıç tarihinden Aralık 2025’e kadar; sudden sensorineural hearing loss, idiopathic sudden sensorineural hearing loss, sudden deafness, intratympanic injection, intratympanic corticosteroid, intratympanic dexamethasone ve intratympanic methylprednisolone anahtar sözcükleri kullanılarak yapılandırılmış bir literatür taraması gerçekleştirildi. Tarama sonucunda 321 kayıt elde edildi; ayrıca önemli derlemelerin, meta-analizlerin ve klinik uygulama kılavuzlarının kaynakçaları incelenerek ek çalışmalar belirlendi. Önceden tanımlanmış seçim kriterleri doğrultusunda; randomize kontrollü çalışmalar, sistematik derlemeler, meta-analizler, klinik uygulama kılavuzları ve erişkin idiyopatik ani sensörinöral işitme kaybı hastalarını içeren gözlemsel çalışmalar önceliklendirildi. Dahil edilen çalışmalarda intratimpanik kortikosteroidlerin primer monoterapi, başlangıçta kombine tedavi veya kurtarma tedavisi olarak uygulanması değerlendirilmiş ve nicel odyometrik sonuçlar raporlanmıştı. İdiyopatik olmayan ani işitme kaybı olguları, pediatrik popülasyon, kortikosteroid dışı intratimpanik tedaviler, hayvan veya yalnızca laboratuvar çalışmaları, olgu sunumları, tam metni bulunmayan kongre özetleri, yinelenen yayınlar ve klinik olarak yorumlanabilir işitme sonuçları sunmayan çalışmalar dışlandı. Tarama sonunda 25 çalışma analize dahil edildi. Kurtarma amaçlı intratimpanik kortikosteroid tedavisi anlamlı klinik yarar sağlamaktadır (OR: 6,04; %95 GA: 3,26-11,2; tedavi edilmesi gereken hasta sayısı ≈3) ve bu bulgu A düzeyinde kanıt ile desteklenmektedir. Başlangıçta uygulanan kombine tedavi, yalnızca sistemik kortikosteroid tedavisine göre daha üstün bulunmuştur (OR: 2,50; %95 GA: 1,95-3,21); bu üstünlük özellikle ileri derecede işitme kaybı olan hastalarda belirgindir. İntratimpanik kortikosteroid monoterapisi ise sistemik kortikosteroid tedavisine karşı aşağı kalmamaktadır [saf ses ortalaması farkı: 2,0 dB]. Tedavi zamanlamasına göre basamaklandırılmış bir yaklaşım önerilmektedir. Kurtarma amaçlı intratimpanik kortikosteroid tedavisi, başlangıç tedavisine rağmen tam iyileşme sağlanamayan tüm hastalara sunulmalıdır. Başlangıçta kombine tedavi, özellikle ileri derecede işitme kaybı olan hastalarda düşünülmelidir. Sistemik kortikosteroid kullanımının kontrendike olduğu durumlarda ise intratimpanik kortikosteroid monoterapisi uygun bir tedavi seçeneğidir.
Congenital hearing loss is one of the prevalent birth defects, with approximately 60% of cases attributed to genetic factors. Genetic hearing loss is broadly classified into syndromic and non-syndromic forms, with non-syndromic hearing loss accounting for 70% of cases. MYO15A mutations are known to cause autosomal recessive non-syndromic hearing loss (ARNSHL), while MT-RNR1 mutations follow a maternal inheritance pattern and are linked to aminoglycoside-induced hearing loss. In this study, a family with diverse manifestations of non-syndromic hearing loss was investigated, including aminoglycoside-induced, congenital profound, and post-lingual profound hearing loss. Through whole exome sequencing, distinct genetic etiologies responsible for hearing loss in affected family members were identified. This is the first report to document the co-occurrence of a compound heterozygous MYO15A mutation alongside an MT-RNR1 mutation within a pedigree. Additionally, it is the first observation of both a homozygous MYO15A c.6956+9C>G mutation and compound heterozygous MYO15A mutations (c.[6956+9C>G]+[4898T>C]) in ARNSHL. These findings broaden the genotype-phenotype spectrum of MYO15A and highlight the critical role of genetic diagnosis in managing hearing loss.
One of the fundamental features of age-related hearing loss is difficulty discriminating signals in the presence of background noise, a functional deficit that may be related to the loss of auditory efferent neurons. We hypothesize that the central degeneration of olivocochlear (OC) efferent neurons results from prolonged lack of afferent input. We investigated the time-course of central degeneration of medial (MOC) and lateral (LOC) OC efferent neurons in genetic mouse models that exhibit hearing loss during development. Tests to verify cochlear function were combined with anatomical and morphological quantification of somatic number, morphology, and location of OC neurons to investigate differences over time in mouse strains with developmental hearing abnormalities. Neuronal tract tracing methods were employed to label OC neurons in 1-, 3-, and 6-month-old CBA/CaH mice with normal hearing; DBA/2J mice with progressive, high frequency hearing loss; and homozygous Shaker2-/- mice with congenital deafness. Deaf Shaker2-/- animals exhibited a striking age-related decrease in numbers of both LOCs and MOCs, and MOC loss appeared to progress in a tonotopic manner. No OC loss was observed in DBA/2J mice, even after progressive elevation of low frequency auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) thresholds. In early life, numbers of OC efferent numbers can appear 'normal' in the complete absence of acoustic input. The retention of these neurons is not affected by late onset high-frequency hearing loss and may indicate functional plasticity of auditory brainstem feedback circuitry when afferent input is retained.
Dental, vision, and hearing impairments are among the most prevalent long-term conditions affecting older adults, contributing to late-life disability and reducing quality of life. Early detection and prevention may reduce avoidable emergency hospitalizations and health system costs while enhancing well-being. Despite this, integrated service delivery across these sensory and oral health domains remains limited, especially in community care settings. This systematic review aimed to synthesize evidence on integrated workforce models involving dental, vision, and hearing professionals within community care settings for older adults. A mixed-method systematic review was conducted using a comprehensive three-step search strategy across MEDLINE, CINAHL, Web of Science, Embase, and Scopus spanning January 2010 to December 2024, and updated in October 2025. In all, 798 articles were identified, with 14 meeting inclusion criteria for convergent integrated synthesis. Included studies involved adults aged 60+ or with samples containing at least 50% older adults, examining community-based models where dental, vision, or hearing personnel collaborated with at least one other health or welfare provider. Critical appraisal and data synthesis followed the Joanna Briggs Institute methodology. Of the 14 studies (5 qualitative, 6 mixed methods, 3 quantitative), 9 focused on dental, 3 on vision, and 2 on hearing workforce models. Studies were primarily from the United States (n=8), Australia (n=2), the Netherlands (n=2), Germany (n=1), and Norway (n=1). Two workforce model types emerged inductively: profession-led models (n=10), characterized by leadership and care coordination, and led by a dental, vision or hearing expert, and collaborative-led models (n=4), featuring shared leadership and an extended skill mix. Profession-led models emphasized clinical interventions; collaborative-led models prioritized health promotion and prevention. Reported outcomes primarily related to service delivery, workforce processes, and patient experiences, including patient satisfaction. Evidence of clinical effectiveness outcomes was limited, and studies varied substantially in design, context and outcome measures. Integrated workforce models in dental, vision, and hearing for older adults in community care show promise in improving care delivery processes and patient-reported outcomes. However, the current evidence base is limited and heterogenous, with few robust evaluations of clinical effectiveness. As such, these models need to undergo further rigorous research to assess their effectiveness, scalability, and context-specific implementation.
We aimed to determine whether computed tomography (CT)-based radiomic features of the inner ear can distinguish the affected side from the contralateral normal-hearing side in patients with idiopathic sudden sensorineural hearing loss (ISSNHL) using a fully automated three-dimensional (3D) segmentation model. Deep learning-based inner ear segmentation followed by radiomics was hypothesized to reveal subtle structural differences associated with ISSNHL. This retrospective study included 318 patients who underwent 420 temporal bone CT scans. An independent test set consisted of 42 inner ear volumes from 21 patients with unilateral ISSNHL, including affected and contralateral normal-hearing sides. Inner ear structures were manually annotated by experienced otologists. A SwinUNETR-based 3D segmentation model was trained using an 8:1:1 dataset split with on-the-fly augmentation. Segmentation performance was evaluated using the Dice similarity coefficient(DSC), Intersection over Union (IoU), accuracy, precision, recall, and F1-score. A total of 1316 radiomic features were extracted from the automatically generated segmentation masks using PyRadiomics, encompassing original, wavelet, and Laplacian of Gaussian (LoG) derived feature classes. Group differences between the ISSNHL-affected and normal-hearing sides were assessed using Welch's t-test or the Mann-Whitney U test, with false discovery rate (FDR) correction applied. The segmentation model demonstrated high and stable performance, with comparable accuracy for ISSNHL-affected and normal-hearing sides. No significant differences were observed in radiomic features between the groups after correction. Principal component analysis and uniform manifold approximation and projection revealed no distinct clustering; the nine shape features with the lowest p-value features exhibited overlapping distributions. CT-based morphological radiomic features did not identify measurable structural differences between the affected and contralateral sides in ISSNHL, supporting the functional or microstructural nature of its underlying pathophysiology. Although automated 3D segmentation using SwinUNETR achieved highly accurate inner ear delineation, CT-derived radiomics demonstrated limited discriminatory value for ISSNHL. Alternative imaging biomarkers, functional imaging approaches, or deep learning-based representation features may be necessary for etiological assessment or prognostication.
Sensorineural hearing loss is influenced by multiple factors, with occupational noise exposure being the key contributor. Dental personnel are routinely exposed to high-frequency sounds from clinical instruments. Although average clinic noise levels are typically below the 85 dBA threshold, cumulative exposure and high peak levels may increase the risk of noise-induced hearing loss (NIHL). This study assessed the workplace noise characteristics, prevalence, and risk factors for NIHL among dental personnel. This cross-sectional study was conducted with 184 staff members at a university dental hospital. Data collection included questionnaires, otoscopic examinations, pure-tone audiometry, and workplace noise measurements. Hearing loss was identified in 30.4% of the participants. Individuals over 30 years of age and those who consumed tobacco and/or alcohol had significantly higher risks (odds ratio = 2.93, 5.81, and 3.21, respectively), whereas caffeine consumption showed a protective association. Technical and maintenance staffs were exposed to higher peak and high-frequency noise than clinical or administrative staff, with 8-h time-weighted averages ranging from 64.3 to 68.9 dBA-all below occupational noise exposure limits. Occupational noise exposure and lifestyle factors contributed to NIHL among dental personnel. Preventive strategies should integrate engineering controls to reduce peak noise alongside health promotion targeting modifiable risks such as tobacco and alcohol use. Early detection and implementation of hearing preservation strategies are essential to reduce the prevalence of NIHL in dental professionals.
Age-related hearing loss (ARHL), or presbycusis, is a very common sensory disorder resulting from cumulative exposure to environmental factors, biological aging and a significant genetic component. Although most cases of ARHL result from the combined influence of numerous low-effect variants, the increasing number of monogenic forms has shown the importance of rare, highly penetrant mutations in ARHL. Advances in whole-exome and whole-genome sequencing have strengthened the evidence for monogenic contributions, identifying deleterious variants consistent with dominant, recessive, or mitochondrial inheritance patterns. These monogenic cases provide valuable insights into the molecular mechanisms underlying cochlear aging and the vulnerability of sensory cells. To date, several genes have been clearly identified as responsible for familial or sporadic late-onset hearing loss, including KCNQ4, GRHL2, ILDR1, EYA4, MYO6, MYO7A, TECTA, WFS1, CDH23, and TMC1. Mutations in these genes affect diverse biological pathways such as potassium recycling, epithelial integrity, transcriptional regulation, mechanotransduction, extracellular matrix stability, and hair cell maintenance-functions that are fundamental to the long-term preservation of hearing. It is important to note that there is a growing overlap between the genes involved in Mendelian deafness and the susceptibility loci identified in ARHL, suggesting the existence of common molecular mechanisms between early-onset hereditary deafness and some forms of progressive ARHL. Furthermore, new data highlight the role of epigenetic regulation, mitochondrial dysfunction, cochlear synaptopathy, and non-coding RNAs in hearing loss. Despite major advances, several challenges remain, including phenotypic heterogeneity, limited representation of non-European populations, and a lack of consistency in the reproducibility of results across studies. Distinguishing between subtypes of ARHL characterized by audiometry-including sensory, neural and synaptopathic, metabolic forms, will likely be essential for improving genetic analyses and precision medicine approaches. Moreover, although polygenic risk scores (PRS) represent a promising strategy for risk prediction, their clinical applicability remains limited. Overall, the integration of monogenic, polygenic, environmental, and epigenetic data will be essential for understanding the complex genetic architecture of ARHL and for developing future personalized therapeutic interventions.
These Philippine clinical practice guidelines (CPG) were developed to guide healthcare professionals on screening for hearing disorders among apparently healthy children and adult Filipinos. Following the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to CPG development recommended in the Department of Health Manual, the Task Force Steering Committee developed four key questions. The evidence review experts reviewed existing CPGs and appraised and summarized evidence. The multisectoral consensus panel reviewed the evidence summaries and developed recommendations during the en banc meeting. Three independent stakeholders reviewed the draft guidelines on the content, clarity, acceptability, applicability, and feasibility of the recommendations. Their feedback was taken into consideration by the steering committee before finalizing the CPG. This CPG provides 10 recommendations based on four prioritized questions in the screening for hearing and vestibular disorders among apparently healthy children (from prenatal to school age) and adults. The consensus panel recommended the screening for hearing and vestibular disorders in certain population groups, based on the available evidence, the burden of disease, the cost of the confirmatory testing, and its applicability to the population.
Refractory sudden sensorineural hearing loss (RSSNHL) remains a therapeutic challenge with limited effective treatment options. Human umbilical cord mesenchymal stem cell-derived small extracellular vesicles (hucMSC-sEVs) have demonstrated otoprotective and regenerative potential in preclinical studies. This Phase 1 trial evaluated the safety of intratympanic hucMSC-sEVs in patients with RSSNHL. This single-center, open-label, single-arm clinical study enrolled RSSNHL patients between June and September 2025 (ChiCTR2500103765). Participants received intratympanic hucMSC-sEVs for five consecutive days across four dose cohorts, ranging from 8 × 10⁸ to 1 × 10¹¹ particles/mL. Follow-up assessments were conducted at 1, 2, 4, and 8 weeks after treatment, during which adverse events (AEs) were recorded, and hearing outcomes were evaluated. Twelve of the thirteen enrolled patients completed the 8-week follow-up. Intratympanic administration of hucMSC-sEVs was well tolerated across all dose levels, with no dose-limited toxicity or serious AEs. The most common AEs were ear pain (5/12), ear fullness (3/12), and transient dizziness (2/12), all characteristic of intratympanic injection and resolving without intervention. In this Phase 1 study, intratympanic hucMSC-sEVs were well tolerated and showed preliminary signals of hearing improvement. Responses were observed only in patients receiving lower dose levels (8 × 10⁸ and 4 × 10⁹ particles/mL) and in those treated within a shorter disease window (≤ 22 days). These exploratory findings require confirmation in larger controlled trials. Trial Registration This study was registered on June 5,2025, at Chinese Clinical Trial Registry (ChiCTR2500103765).
The pathogenesis of age-related hearing loss (ARHL) remains incompletely understood. The blood labyrinth barrier (BLB) play a crucial role in maintaining cochlear homeostasis, yet in the stria vascularis (SV) of aged C57BL/6J mice, pericytes (PCs) undergo migration, potentially increasing BLB permeability and contributing to vascular leakage, which may exacerbate ARHL. The underlying molecular mechanisms, however, remain elusive. Studies have suggested gender disparities in auditory function linked to estrogen levels, with G1, an activator of the estrogen membrane receptor GPER, capable of activating large-conductance calcium-activated potassium channels (BKCa). Our previous research has indicated a decline in BKCa channel expression on pericytes with aging. Our study aimed to investigate whether G1 protects against ARHL by modulating BKCa channels in aged cochlear pericytes, thereby influencing pericyte migration. In vivo experiments revealed reduced BKCa channel expression in cochlear SV pericytes of aged mice, which was upregulated following G1 administration, accompanied by improved hearing and decreased BLB permeability. In vitro, G1 increased BKCa channel expression in pericytes and diminished their migratory capacity. Further investigation uncovered a close association between aged pericyte migration and both the BKCa channel and the MEK/ERK signaling pathway. These findings provide experimental evidence to elucidate he impact of estrogen on auditory function and offer novel targets and strategies for preventing and treating ARHL.
This study was aimed at evaluating the potential otoprotective effects of resveratrol (Changsha Huir Biological-Tech) on noise-induced hearing loss (NIHL) in a Wistar rat model. The study employed a randomized controlled design. The noise used for stimulation was white noise, centered at a frequency of 4000 Hz (3564-4490 Hz), with an intensity of 100 dB SPL, for a period of 10 consecutive days at 8 h/day. Thirty rats were randomly assigned to three groups: a control nonexposed-to-noise group (n = 10) that received a vehicle solution of DMSO (dimethyl sulfoxide) (Sigma-Aldrich), a noise-exposed study group (n = 10) that received a vehicle solution of DMSO, and a resveratrol study group that was exposed to noise and received 10 mg/kg/day of resveratrol. All groups underwent distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) assessments at three time points: initial examination (D0), examination after 10 consecutive days of noise exposure (D15), and examination after 15 days of acoustic rest (D30). Histological evaluations were conducted on cochlear tissues after euthanasia. Statistical analyses were performed using Prism software to determine differences between groups and across time points. The amplitude values, signal-to-noise ratios of DPOAE, ABR thresholds, and cochlear morphology between the experimental and control groups were significantly different from each other. The findings suggest that resveratrol exerts a partial otoprotective effect, possibly delaying the onset of NIHL. However, further research, particularly molecular research, is needed to better understand its therapeutic mechanism and its specific impact on auditory metabolic processes.
To investigate whether zinc deficiency is associated with tinnitus severity in patients with chronic idiopathic tinnitus and normal hearing. This prospective, cross-sectional study included 107 patients with chronic idiopathic tinnitus and normal hearing selected from 409 patients evaluated at the tinnitus clinic between January 2021 and December 2023. Serum zinc levels, Tinnitus Handicap Inventory (THI) scores, and tinnitus loudness matching tests were assessed. Zinc deficiency was defined as serum zinc <66 μg/dL. Of 107 patients, 22 (20.6%) had zinc deficiency. Zinc-deficient patients showed significantly higher total THI scores (48.09 ± 25.95 vs. 36.28 ± 21.91, P=.032) and functional component scores (19.09 ± 11.87 vs. 13.13 ± 9.68, P=.016). Correlation analysis revealed negative correlations between continuous serum zinc levels and all THI components, though none reached statistical significance. Objective tinnitus loudness did not differ significantly between groups. Zinc deficiency is associated with greater tinnitus severity in patients with normal hearing, particularly affecting functional aspects of daily life. Screening for zinc deficiency and targeted supplementation might offer a potential therapeutic approach for this specific patient population.
Tinnitus is a known long-term health effect of noise exposure. Whether susceptible genotypes predispose noise-exposed workers to tinnitus remains unclear. This study investigated the interactive effects of noise exposure, auditory function, and glutathione S-transferase (GST) gene polymorphisms on tinnitus risk. We conducted a cross-sectional study among steelworkers. Participants underwent audiological testing to assess hearing levels and were surveyed for tinnitus. Blood samples were genotyped for GSTM1 and GSTT1 deletion polymorphisms using polymerase chain reaction. Multivariable logistic regression was used to evaluate associations between tinnitus and pure-tone audiometry (PTA), distortion product otoacoustic emission (DPOAE), and GST genotypes while controlling for age and other covariates. Among 239 male steelworkers (mean age ± SD: 48.29 ± 7.6 years), 27% reported tinnitus. Cumulative noise exposure and thresholds at low- and high-frequency PTA were significantly associated with tinnitus (adjusted odds ratio (OR) = 1.03, 1.06, and 1.04, 95% confidence interval (CI) = [1.00,1.06], [1.02,1.11], and [1.02,1.06], p = 0.045, 0.002, <0.001, respectively). Although neither DPOAE nor GSTM1 nor GSTT1 genotypes showed a significant effect on tinnitus, we observed a significant interaction between low-frequency PTA and the GSTM1 genotype (p = 0.03). Specifically, compared with workers with non-null GSTM1 genes, workers with the GSTM1-null genotype were significantly more susceptible to low-frequency PTA-associated tinnitus (OR = 1.02 and 1.13, 95% CI = [0.96,1.08] and [1.06,1.22], respectively). The interactive effect of auditory functional status and antioxidant gene polymorphisms suggests that hair cell damage and oxidative stress in the cochlea both contribute to tinnitus development.
Residential altitude has been proposed as a potential determinant of auditory function, but evidence from long-term high-altitude residents remains limited. This cross-sectional study included 187 plateau residents aged ≤50 years undergoing health examination at the Affiliated Hospital of Qinghai University. Participants were classified into lower- (2,200-2,499 m, n = 79), middle- (2,500-3,499 m, n = 51), and higher-altitude (≥3,500 m, n = 57) strata according to long-term residential altitude. Mean bilateral thresholds at 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, and 8 kHz, together with LM-PTA and HF-PTA, were compared across groups. Complementary Kruskal-Wallis analyses, minimally and fully adjusted models, continuous-altitude analyses, exploratory quadratic-term analysis for PTA at 8 kHz, and repeated-measures ANCOVA were performed. Unadjusted analyses showed more pronounced between-group differences at higher frequencies, with statistically significant differences for HF-PTA, PTA at 4 kHz, PTA at 8 kHz, and LM-PTA. Continuous-altitude models did not support a stable linear trend. In the fully adjusted model, altitude-stratified effects were no longer statistically significant for HF-PTA, PTA at 4 kHz, or LM-PTA, but remained statistically significant for PTA at 8 kHz (p = 0.032). Bonferroni-corrected comparisons showed that only the difference in PTA at 8 kHz between the lower- and middle-altitude strata remained statistically significant. The fully adjusted repeated-measures ANCOVA did not show a statistically significant Frequency × altitude group interaction. Hearing-threshold differences across residential altitude strata were more apparent at higher frequencies in unadjusted analyses; after adjustment for age, sex, and other clinical factors, the most robust independent altitude-stratified association remained at 8 kHz.
The cochlear microphonic (CM) primarily reflects the composite receptor potential of outer hair cells (OHCs), providing an objective assessment of OHC mechanoelectrical transduction (MET) capacity. However, systematic studies on CM in basic research remain scarce, and baseline CM values for CBA/CaJ mice have not yet been established. Moreover, whether CM can functionally differentiate between auditory neuropathy (AN) and noise-induced hearing loss (NIHL) has not been systematically addressed. This study aimed to establish normative CM reference values for CBA/CaJ mice and to explore the utility of CM as an objective electrophysiological tool for assessing OHC function across different pathophysiological conditions. CM was recorded from the round window in three mouse models: wild-type (WT) CBA/CaJ mice (1, 2, and 7 months), Aifm1 p.R450Q knock-in AN mice, and NIHL models of permanent threshold shift (PTS) and temporary threshold shift (TTS). Input-output (I/O) nonlinearity and frequency-specific were analyzed. In WT mice, CM amplitude exhibited an approximately linear relationship with stimulus intensity at levels ≤90dB SPL. When the intensity exceeded 90dB SPL, the amplitude saturated and subsequently declined, demonstrating nonlinear characteristics under high-intensity stimulation. Compared to 1- and 2-month-old WT mice, CM amplitude was reduced at 7 months of age. In AN mouse models, CM waveforms remained generally normal, but amplitude increased at 1 month and declined by 7 months. In noise-exposed mice, CM amplitude significantly decreased in the PTS group, while only a slight reduction was observed in the TTS group. This study establishes normative CM values for CBA/CaJ mice and demonstrates that CM profiling provides a functional differentiation between AN and two types of NIHL. These findings support CM as a robust, objective tool for assessing OHC function in murine models and encourage broader implementation of CM testing in both preclinical research and clinical diagnostics.
Diabetic retinopathy is a well-recognized microvascular complication of diabetes mellitus; however, diabetes-associated auditory dysfunction remains less well characterized, particularly with respect to its longitudinal progression. In this study, we performed a cross-sectional assessment of ocular and auditory function in Zucker diabetic fatty (ZDF) rats and examined their relationships with chronic hyperglycemia. Forty male ZDF (fa/fa) rats and thirty-two age-matched control rats (fa/-) were evaluated at 12, 20, 28, and 36 weeks of age. Ocular changes were assessed using slit-lamp microscopy and fluorescein fundus angiography, while auditory function was evaluated using auditory brainstem response (ABR) testing across frequencies from 4 to 32 kHz. Fasting blood glucose levels were monitored throughout the study. ZDF rats developed sustained hyperglycemia from 12 weeks of age onward. Elevated ABR thresholds were first observed at high frequencies (32 kHz) at 12 weeks, followed by progressive involvement of mid frequencies (16 and 24 kHz) at 20 weeks and all tested frequencies (4-32 kHz) at 28-36 weeks. Retinal vascular leakage and cataract formation increased with disease duration. Fasting blood glucose levels showed strong positive associations with ABR thresholds across all frequencies (r = 0.72-0.85, P < 0.01) and with cataract severity. These findings show that chronic hyperglycemia in ZDF rats is accompanied by progressive auditory and ocular dysfunction, providing longitudinal functional evidence of multisystem sensory impairment in a diabetic animal model.
Assigning individuals with hearing impairment to auditory profiles can support a better understanding of the causes and consequences of hearing loss and facilitate profile-based hearing-aid fitting. However, the factors influencing auditory profile generation remain insufficiently understood, and existing profiling frameworks have rarely been compared systematically. This study therefore investigated the impact of two key factors-the clustering method and the number of profiles-on auditory profile generation. In addition, eight established auditory profiling frameworks were systematically reviewed and compared using intrinsic statistical measures and manifold learning techniques. Frameworks were evaluated with respect to internal consistency (i.e., grouping similar individuals) and cluster separation (i.e., clear differentiation between groups). To ensure comparability, all analyses were conducted on a common open-access dataset, the extended Oldenburg Hearing Health Record (OHHR), comprising 1,127 participants (mean age = 67.2 years, SD = 12.0). Results showed that both the clustering method and the chosen number of profiles substantially influenced the resulting auditory profiles. Among purely audiogram-based approaches, the Bisgaard auditory profiles demonstrated the strongest clustering performance, whereas audiometric phenotypes performed worst. Among frameworks incorporating supra-threshold information in addition to the audiogram, the Hearing4All auditory profiles achieved the lowest normalized Davies-Bouldin (DB) score, while the BEAR auditory profiles performed better on the other intrinsic measures. In conclusion, separability should be considered a primary criterion in auditory profile generation, as it directly determines how meaningfully different profiles can be distinguished in practice. Manifold learning and intrinsic measures enable systematic comparisons of auditory profiling frameworks and identify the Hearing4All auditory profile as a promising approach for future research.
Lassa fever vaccine trials are hampered by knowledge gaps on disease incidence, at-risk populations, sequelae, and transmission risks. We aimed to estimate symptomatic Lassa virus infection incidence in endemic areas and determine community Lassa fever case fatality risk (CFR), malaria co-infection, hearing loss in survivors, and household risk factors. The Enable 1.0 Lassa Research Study was a prospective, multisite, cohort study conducted in 111 rural communities across Benin, Liberia, Nigeria, and Sierra Leone, with documented Lassa fever transmission. Households were identified using country-specific random sampling approaches, and eligible household members aged at least 2 years were invited to participate following community engagement and informed consent. Eligibility required participants to be afebrile at enrolment, resident in the community for at least 6 months, intending to remain for the study duration, and able and willing to comply with study procedures. Participants were monitored for suspected Lassa fever symptoms over 18-30 months. The blood samples of people with suspected Lassa fever were evaluated for Lassa virus by RT-PCR and malaria by rapid diagnostic test. The hearing status of people who survived Lassa fever was tested at the hospital before discharge and 4 months later. Crude Lassa fever incidence rates (IRs) and rate ratios (IRRs) were estimated using Poisson regressions. Household risk factors were analysed using mixed-effect logistic models. Between Nov 30, 2020 and Nov 20, 2023, among 20 131 participants, 8183 people with suspected Lassa fever were evaluated, revealing 39 people with Lassa fever, representing an overall Lassa fever IR of 1·27 people with Lassa fever per 1000 person-years (95% CI 0·88-1·84). Lassa fever risk was higher in children aged 2-17 years than in adults (adjusted IRR 1·96, 95% CI 1·04-3·72) but did not differ by sex. CFR was 13% (five of 39). 27 (69%) of 39 people with Lassa fever had malaria co-infection, nine (32%) of 28 had hearing loss at discharge, and 14 (48%) of 29 had hearing loss 4 months after discharge. No household-level characteristics were significantly associated with Lassa fever. Symptomatic Lassa virus infection occurs infrequently in West Africa, meaning large vaccine trials are required to measure efficacy. Trials should target children, who are at higher risk of Lassa fever, alongside the further development of targeted school-based health education and household-level risk communication programmes in endemic communities. The high prevalences of malaria co-infection and hearing loss after infection warrant further exploration in future trials and reinforce the need for integrated community fever management strategies that include Lassa fever as a differential diagnosis. The Coalition for Epidemic Preparedness Innovations.