Age-Related Hearing Loss

Ferroptosis and hearing loss: from molecular mechanisms to therapeutic interventions

Hearing loss profoundly affects social engagement, mental health, cognition, and brain development, with sensorineural hearing loss (SNHL) being a major concern. Linked to ototoxic medications, ageing, and noise exposure, SNHL presents significant treatment challenges, highlighting the need for effective prevention and regeneration strategies. Ferroptosis, a distinct form of cell death featuring iron-dependent lipid peroxidation, has garnered interest due to its potential role in cancer, ageing, and neuronal degeneration, especially hearing loss. The emerging role of ferroptosis as a crucial mediator in SNHL suggests that it may offer a novel therapeutic target for otoprotection. This review aims to summarise the intricate connection between ferroptosis and SNHL, offering a fresh perspective for exploring targeted therapeutic strategies that could potentially mitigate cochlear cells damage and enhance the quality of life for individuals with hearing impairments.

miR‑34a induces apoptosis and pyroptosis in D‑Galactose‑induced aging cochlear hair cells via inhibiting TFAM and promoting mitochondrial dysfunction in vitro and in vivo

Aging of the auditory system causes progressive hearing deficit and affects millions of people; however, the underlying mechanism remains largely unknown. D‑galactose (D‑gal)‑induced aging models were established in vitro using HEI‑OC1 cells and in vivo using C57BL/6 mice to investigate the role of miR‑34a in age‑related hearing loss (ARHL). HEI‑OC1 cells were treated with D‑gal for, while mice received daily intraperitoneal injections of D‑gal for six weeks. Molecular and functional analyses, including reverse transcription‑quantitative PCR, Western blot, flow cytometry, immunofluorescence, and dual‑luciferase reporter assays, were performed to evaluate oxidative stress, mitochondrial dysfunction, apoptosis, and pyroptosis, with miR‑34a inhibitor and DRP1 inhibitor (Mdivi‑1) used to assess their regulatory effects. D‑gal induced hair cell loss by apoptosis and pyroptosis, which was modulated by microRNA (miR)‑34a via mitochondrial dysfunction in vitro and in vivo. Inhibition of mitochondrial transcription factor A (TFAM), which is the target gene of miR‑34a, was involved in the underlying molecular mechanism. miR‑34a mediated apoptosis and pyroptosis in D‑gal‑induced cochlear hair cells via inhibiting TFAM and promoting mitochondrial dysfunction in vitro and in vivo and may serve as a new potential target for future ARHL treatment.

Novel_circ_0004013 targeting miR-29a-3p affects age-related hearing loss in miR-29a mouse model by RNA-seq analysis

Age-related hearing loss (ARHL) is a gradual, symmetrical sensorineural disorder. Exploring the pathogenesis of ARHL from a biological perspective is important for its treatment. In this study, we analyzed the circRNA expression profiles of 2-month-old miR-29a+/+ mice and miR-29a-/- mice by transcriptome sequencing to investigate the role of circRNAs in ARHL. We identified 12 differentially expressed circRNAs in the two groups. Our focus was on circRNAs predicted to regulate miR-29a, with novel_circ_0004013 identified as having a targeted binding relationship with miR-29a-3p. Dual luciferase assays confirmed that miR-29a-3p is a direct target of novel_circ_0004013. Fluorescence in situ hybridization (FISH) was employed to localize the novel_circ_0004013 in HEI-OC1 cells and the cochlea. Novel_circ_0004013 was mainly expressed in the cytoplasm. In the hair cells (HCs) and stria vascularis (SV) regions of miR-29a-/- mice, novel_circ_0004013 expression was higher than the corresponding regions in miR-29a+/+ mice. Furthermore, Western blot assays revealed that levels of oxidative stress and apoptosis were significantly decreased in HEI-OC1 cells following the knockdown of novel_circ_0004013, whereas these levels were significantly increased in HEI-OC1 cells after the knockdown of miR-29a-3p. It was indicated in rescue assays that novel_circ_0004013 expedited oxidative stress and apoptosis of HEI-OC1 cells via modulation on miR-29a-3p. These findings may reveal the important role of novel_circ_0004013 in hearing loss and provide a new perspective and theoretical basis for the molecular mechanism of ARHL.

Cognitive and metabolic signatures of early and late-onset depression: A comparative study

BACKGROUND

Early-onset depression (EOD) and late-onset depression (LOD) are prevalent subtypes of major depressive disorder (MDD), but the clinical distinction between EOD and LOD remains blurred due to nonspecific symptoms and lack of biomarkers. This study aims to elucidate the characteristics in cognitive function and biochemical metabolism of EOD and LOD, and to identify biological factors influencing age of onset (AOO).

METHODS

Seventy patients with MDD (40 with EOD and 30 with LOD) and sixty-eight age-matched healthy controls (HC) were included in this study. Participants were evaluated for clinical features, cognitive function, and serum trace elements levels. Proton magnetic resonance spectroscopy (1H-MRS) was employed to quantify neurometabolites levels, including N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr).

RESULTS

Patients with LOD experienced more episodes and severe depressive symptoms than those with EOD (p = 0.025, p < 0.001). EOD patients performed significantly worse than LOD patients on social cognition (p = 0.005), while LOD patients performed worse than EOD patients on reasoning and problem solving (p = 0.005). Additionally, LOD patients displayed higher ceruloplasmin (Cp) levels compared to EOD patients (p = 0.004), but no difference was found in neurometabolic levels between EOD and LOD. Multiple linear regression indicated a positive correlation between serum Cp levels and AOO of depression (p < 0.001), while bilateral thalamic NAA/Cr showed a negative correlation with AOO (p = 0.012, p = 0.016).

CONCLUSIONS

Patients with EOD were characterized by social cognition impairments, while patients with LOD were marked by reasoning and problem-solving deficits. Serum Cp levels demonstrated an AOO-related effect and served as a positive predictor for the AOO of depression. Furthermore, a negative correlation has been established between bilateral thalamic NAA/Cr and the AOO of MDD.

LIMITATIONS

The limited sample size and the challenge in distinguishing whether observed results are attributed to age or AOO effects.

Middle-aged CBA/CaJ mice exhibit auditory dysfunction in background noise

Aging is associated with deficits in auditory functioning. Characterization of auditory deficits that originate in middle-age is crucial for understanding the initial age-related functional impairments and the spatio-temporal progression of age-related auditory pathophysiology. Early age-related deficits in auditory processing are evident in difficult listening conditions, such as background noise, before becoming evident in quiet. To investigate the effect of noise on age-related auditory dysfunction, we collected suprathreshold auditory brainstem responses (ABRs) from young, middle-aged, and aged CBA/CaJ mice in quiet and broad-band background noise. We utilized multiple ABR metrics, including phase locking value (PLV), a measure of neural synchrony correlated to speech-in-noise understanding in humans. Despite no differences in auditory processing in quiet between young and middle-aged mice, middle-aged mice exhibited a distinct auditory phenotype from both young and aged mice in background noise conditions. We found that noise significantly decreased amplitude in middle-aged mice more than in young and aged mice. Noise significantly increased latencies for wave I and V in young mice, but only affected wave V in middle-aged mice and did not affect aged latencies. Noise significantly decreased PLV in middle-aged mice to a greater extent than in young mice, but to a lesser extent in aged mice. These results show that middle-aged mice have a distinct, auditory dysfunction phenotype evident in background noise. Our data show that suprathreshold auditory function in noise can identify early age-related hearing loss and can be used as a sensitive tool for detecting auditory dysfunction in normal hearing animal models.

Association of GRM7 Polymorphisms with Bilateral Auditory Regions Glutamate and Coupling with Glutathione in ARHL Patients

This study aimed to investigate the relationship between GRM7 polymorphisms and the levels of glutamate (Glu) and glutathione (GSH) in bilateral auditory regions (ARs) of ARHL patients. Seventy-eight ARHL patients (mean age, 65.94 years ± 3.37 [SD]; 44 men) and 46 normal hearing (NH) controls (mean age, 65.72 years ± 2.32 [SD]; 28 men) were enrolled. Glu and GSH levels in bilateral ARs of all participants were measured and estimated by using magnetic resonance spectroscopy (MRS) and LCModel. In addition, we collected peripheral venous blood samples from all participants for DNA extraction and investigated polymorphisms in the GRM7 gene using TaqMan SNP genotyping. The results showed that Glu and GSH levels in bilateral ARs were significantly lower in GRM7 high-risk group compared with GRM7 low-risk group, regardless of disease status (all pglu < 0.001; all pgsh = 0.001). Furthermore, GRM7 low-risk ARHL group had lower Glu levels in bilateral ARs than GRM7 low-risk NH group, whereas no difference was observed between NH and ARHL groups in high-risk (all pglu < 0.05; all pglu > 0.05). Finally, we found that Glu and GSH levels were positively correlated only in the low-risk NH group (rleft = 0.536 p = 0.007; rright = 0.545 p = 0.006). The glutamatergic dysfunction in ARs may be associated with GRM7 polymorphisms, and redox reactions are involved in regulating the glutamatergic abnormalities. The TT genotype of GRM7 rs11928865 SNP is more vulnerable to damage from the antioxidant and the glutamatergic system.

The first hearing aid: are there differences in the expectations of patients treated in the public and private healthcare systems?

INTRODUCTION

One of the treatments for hearing loss (HL) is the use of a Hearing Aid (HA). Evaluating expectations regarding the use of HA provides a broader perspective on HL and allows for the planning and implementation of effective rehabilitation strategies.

OBJECTIVE

To assess and compare the expectations of adults and older adults treated in public and private healthcare services regarding the use of HA.

MATERIALS AND METHODS

This study included 50 patients with HL, with 25 attended in a public health service, and 25 attended in a private service. Participants answered the Expected Consequences of Hearing Aid Ownership (ECHO).

RESULTS

Candidates for HA use exhibited higher expectations regarding Positive Effect, that is, the benefits the device can provide in daily life. In the public service, older patients had higher expectations regarding personal image. In the private healthcare service, a significant positive correlation was observed between the Personal Image subscale and the individual's level of education.

CONCLUSION

It can be concluded that expectations regarding hearing aid use were associated with healthcare service type, age, and education level.

Advancements of ROS-based biomaterials for sensorineural hearing loss therapy

Sensorineural hearing loss (SNHL) represents a substantial global health challenge, primarily driven by oxidative stress-induced damage within the auditory system. Excessive reactive oxygen species (ROS) play a pivotal role in this pathological process, leading to cellular damage and apoptosis of cochlear hair cells, culminating in irreversible hearing impairment. Recent advancements have introduced ROS-scavenging biomaterials as innovative, multifunctional platforms capable of mitigating oxidative stress. This comprehensive review systematically explores the mechanisms of ROS-mediated oxidative stress in SNHL, emphasizing etiological factors such as aging, acoustic trauma, and ototoxic medication exposure. Furthermore, it examines the therapeutic potential of ROS-scavenging biomaterials, positioning them as promising nanomedicines for targeted antioxidant intervention. By critically assessing recent advances in biomaterial design and functionality, this review thoroughly evaluates their translational potential for clinical applications. It also addresses the challenges and limitations of ROS-neutralizing strategies, while highlighting the transformative potential of these biomaterials in developing novel SNHL treatment modalities. This review advocates for continued research and development to integrate ROS-scavenging biomaterials into future clinical practice, aiming to address the unmet needs in SNHL management and potentially revolutionize the treatment landscape for this pervasive health issue.

Advancing precision ear medicine: leveraging animal models for disease insights and therapeutic innovations

Gene therapy offers significant promise for treating inner ear disorders, but its clinical translation requires robust preclinical validation, often reliant on animal models. This review examines the role of these models in advancing gene therapeutics for inherited inner ear disorders, focusing on successes, challenges, and treatment solutions. By providing a precise understanding of disease mechanisms, these models offer a versatile preclinical platform that is essential for assessing and validating therapies. Successful gene supplementation and editing have shown potential in restoring hearing and balance functions and preventing their decline. However, challenges such as limitations in gene delivery methods, surgical access, immune responses, and discrepancies in disease manifestation between animal models and humans hinder clinical translation. Current efforts are dedicated to developing innovative strategies aimed at enhancing the efficiency of gene delivery, overcoming physical barriers such as the blood-labyrinth barrier, improving target specificity, and maximizing therapeutic efficacy while minimizing adverse immune responses. Diverse gene supplementation and editing strategies, along with evolving technologies, hold promise for maximizing therapeutic outcomes using disease relevant models. The future of inner ear gene therapeutics will hinge on personalized therapies and team science fueling interdisciplinary collaborations among researchers, clinicians, companies, and regulatory agencies to expedite the translation from bench to bedside and unlock the immense potential of precision medicine in the inner ear.

Audiometry as a predictive proxy for balance dysfunction

Dizziness and vertigo are common complaints, often linked to inner ear or neurological issues. Although inner ear houses both the cochlea and vestibule, the relationship between hearing loss and vertigo is still a longstanding controversy. Here, we probed systematic audiometry and vestibular function on 1115 patients, attending consultation for dizziness and vertigo. Peripheral vestibular pathologies accounted for 49.3% of the diagnoses, while 41.1% were attributed to central pathologies. Principal component analysis identified six distinct audiometric phenotypes, which were then correlated with vestibular test outcomes. Caloric irrigation results demonstrated a correlation with hearing loss in the more affected ear. Rotatory chair testing was associated with overall hearing loss. Head impulse testing revealed that lateral and posterior semicircular canal function were age-dependent and correlated with high-frequency hearing loss. Notably, anterior semicircular canal function was independent of both audiometric phenotypes and age. We subsequently analyzed the distribution of audiometric phenotypes across diagnostic categories. Vestibular migraine (15.5% of the cohort) primarily affected younger women with normal hearing. Bilateral vestibulopathy (16.7% of the cohort), benign paroxysmal positional vertigo (9.7%), and dementia (2.2%) were more frequently observed in older patients and those with hearing loss. Ménière's disease (4%) and vestibular neuritis/labyrinthitis (3.9%) were associated with younger patients and unilateral or asymmetrical hearing loss. Our findings suggest that audiometric assessments can provide predictive insights into vestibular dysfunction. These audiometric phenotypes represent valuable tools for refining diagnoses and facilitating personalized management of patients with balance disorders.

Identifying educational interventions aimed at improving communication with older adults with age-related hearing loss: a scoping review and thematic analysis

OBJECTIVE

This scoping review summarises existing interventions aimed at educating individuals without hearing loss to enhance their communication with older adults experiencing age-related hearing loss (ARHL).

DESIGN

Data collection employed a systematic search approach as per the guidelines of Arksey & O'Malley, and followed the PRISMA-ScR guidelines.

STUDY SELECTION

A structured search was conducted involving four research databases from 2000 to 2023, with additional grey literature searching. Original papers written in English, reporting the design and implementation of educational interventions targeting communication with older adults with ARHL, were included. Reflexive thematic analysis was used to identify themes related to intervention type and methodology, and key findings.

RESULTS

13 eligible intervention studies were identified and summarised. Four main themes were described: (1) education and communication skills training; (2) mode of intervention delivery; (3) appropriateness of the intervention and satisfaction among participants; (4) transforming attitudes on hearing loss for better relationships and emotional well-being.

CONCLUSIONS

The link between hearing loss and diminished quality of life in older adults with ARHL highlights the importance of ongoing development of innovative educational programmes targeting effective communication in diverse settings, including clinical environments.

Heavy metal biomarkers and their impact on hearing loss risk: a machine learning framework analysis

Background

Exposure to heavy metals has been implicated in adverse auditory health outcomes, yet the precise relationships between heavy metal biomarkers and hearing status remain underexplored. This study leverages a machine learning framework to investigate these associations, offering a novel approach to understanding the interplay between environmental exposures and hearing loss.

Methods

We conducted a retrospective cross-sectional analysis using data from the 2012-2018 National Health and Nutrition Examination Survey (NHANES), encompassing 2,772 participants after applying exclusion criteria. Demographic, clinical, and heavy metal biomarker data (e.g., blood lead and cadmium levels) were analyzed as features, with hearing loss status-defined as a pure-tone average threshold exceeding 25 dB HL across 500, 1,000, 2000, and 4,000 Hz in the better ear-serving as the binary outcome. Multiple machine learning algorithms, including Random Forest, XGBoost, Gradient Boosting, Logistic Regression, CatBoost, and MLP, were optimized and evaluated. Model performance was assessed using accuracy, area under the curve (AUC), sensitivity, and specificity, while SHAP (SHapley Additive exPlanations) elucidated feature contributions.

Results

The CatBoost model demonstrated the strongest performance, achieving an accuracy of 74.9% and an AUC of 0.792 on test data. Age, education level, gender, and blood levels of lead and cadmium emerged as the most significant features associated with hearing loss, as determined by SHAP analysis. These findings highlight key correlates of hearing impairment within the study population.

Conclusion

This study underscores the utility of a machine learning framework in identifying associations between heavy metal biomarkers and hearing loss in a nationally representative sample. While not designed to forecast hearing loss over time, our findings suggest potential clinical relevance for identifying individuals with elevated heavy metal exposure who may warrant further audiometric evaluation. This work lays a foundation for future longitudinal studies to explore these relationships more comprehensively.

Senolytic treatment alleviates cochlear senescence and delays age-related hearing loss in C57BL/6J mice

BACKGROUND

Age-related hearing loss (ARHL) is a prevalent sensory deficit that significantly affects quality of life in older individuals. Cellular senescence contributes to various age-related degenerative disorders. However, its effect on ARHL remains unclear.

PURPOSE

The aim of this study was to explore the therapeutic potential of senolytics in attenuating cochlear senescence and delaying the progression of ARHL.

METHODS

The senolytic drugs dasatinib and quercetin (D + Q) were used to target senescent cells at different stages of ARHL in C57BL/6J mice. The impact of D + Q treatment on ARHL progression and cochlear degeneration was also assessed. Additionally, the protective effects of D + Q treatment were evaluated in HEI-OC1 auditory cells and cochlear explants. Transcriptomic analysis was conducted on cochlear explants subjected to different treatments.

RESULTS

D + Q treatment at an early stage of ARHL significantly delayed ARHL progression and alleviated cochlear degeneration in male and female C57BL/6J mice. Treatment of mice with normal hearing also mitigated age-related hair cell loss. In HEI-OC1 auditory cells, D + Q treatment exerted protective effects by alleviating the senescence-associated secretory phenotype (SASP). Transcriptomic analysis of cochlear explants revealed that downregulation of inflammatory cytokines and chemokines was involved in the beneficial effects of D + Q treatment against cellular senescence. Mechanistically, D + Q treatment alleviated hair cell senescence via binding to NF-κB and inhibiting its activity.

CONCLUSION

Senolytics may offer a novel therapeutic strategy for attenuating cochlear senescence and slowing the progression of ARHL.

Exploring the bioactive ingredients of three traditional Chinese medicine formulas against age-related hearing loss through network pharmacology and experimental validation

Traditional Chinese medicine (TCM) formulas, including the Er-Long-Zuo-Ci pill, Tong-Qiao-Er-Long pill, and Er-Long pill, have long been utilized in China for managing age-related hearing loss (ARHL). However, the specific bioactive compounds, pharmacological targets, and underlying mechanisms remain elusive. This study aims to find the shared bioactive ingredients among these three formulas, uncover the molecular pathways they regulate, and identify potential therapeutic targets for ARHL. Furthermore, it seeks to validate the efficacy of these major components through both in vivo and in vitro experiments. Common bioactive ingredients were extracted from the TCMSP database, and their putative target proteins were predicted using the Swiss Target Prediction database. ARHL-related target proteins were collected from GeneCards and OMIM databases. Our approach involved constructing drug-target networks and drug-disease-specific protein-protein interaction networks and conducting clustering, topological property analyses, and functional annotation through GO and KEGG enrichment analysis. Molecular docking analysis was utilized to delineate interaction mechanisms between major bioactive ingredients and key target proteins. Finally, in vivo and in vitro experiments involving ABR recording, immunofluorescent staining, HE staining, and quantitative PCR were conducted to validate the treatment effects of flavonoids on the declining auditory function in DBA/2 J mice. We identified 11 common chemical compounds across the three formulas and their associated 276 putative targets. Additionally, 3350 ARHL-related targets were compiled. As an intersection of the putative targets of the common compounds and ARHL-related proteins, 145 shared targets were determined. Functional enrichment analysis indicated that these compounds may modulate various biological processes, including cell proliferation, apoptosis, inflammatory response, and synaptic connections. Notably, potential targets such as TNFα, MAPK1, SRC, AKT, EGFR, ESR1, and AR were implicated. Flavonoids emerged as major bioactive components against ARHL based on target numbers, with molecular docking demonstrating diverse interaction models between these flavonoids and protein targets. Furthermore, baicalin could mitigate the age-related cochlear damage and hearing loss of DBA/2 J mice through its multi-target and multi-pathway mechanism, involving anti-inflammation, modulation of sex hormone-related pathways, and activation of potassium channels. This study offers an integrated network pharmacology approach, validated by in vivo and in vitro experiments, shedding light on the potential mechanisms, major active components, and therapeutic targets of TCM formulas for treating ARHL.

Noise-induced hearing loss and blood factors: results from a comprehensive cross-sectional study in Iran

BACKGROUND

Noise-induced hearing loss (NIHL) is a common occupational hazard and a leading cause of hearing impairment among industrial workers. Previous studies have primarily focused on the association between physiological parameters and excessive noise exposure (above 85 dB). This study investigates the impact of sound exposure below the permissible limit (between 82 and 85 dB) on blood factors and hearing loss.

METHODS

This cross-sectional analytical study examined 8946 male facility technicians from various industries in Iran, who were exposed to sound levels between 82 and 85 decibels (action limit) over a period of one year. The study examined various blood factors, including complete blood cell count (CBC), blood group (BG), fasting blood glucose (FBS), lipid factors such as triglycerides (TG) and cholesterol (Chol), and also blood pressure (BP). Additionally, the hearing status of participants was evaluated using pure tone audiometry for both ears.

RESULTS

The results indicated that age, work experience, SBP, FBS, Chol, Hb, Plt, and Hct were the main factors influencing hearing loss. FBS showed the highest impact on workers' hearing loss, accounting for 36.70% of the variance. Furthermore, Hb and PLT followed with weights of 19.10% and 12.4%, respectively. However, no significant relationship was observed concerning the blood group type.

CONCLUSION

Exposure to noise levels below the permissible limit can lead to hearing loss in individuals. Moreover, FBS, Hb, and PLT were identified as blood factors affecting hearing loss in people. Understanding this will provide the basis for future guidelines on how to care for these workers.

Temporal trends in prevalence and years of life lived with disability for hearing loss in China from 1990 to 2021: an analysis of the global burden of disease study 2021

Background

Hearing loss (HL) poses a serious threat to the health and quality of life of Chinese population. This study analyzes the burden of HL in China from 1990 to 2021 and projects future trends in next 15 years.

Methods

Data derived from the Global Burden of Disease (GBD) 2021 study were utilized. The join-point regression model was employed to calculate the average annual percentage change (AAPC) in the prevalence and years of life lived with disability (YLDs) of HL. Age-period-cohort analysis was conducted to assess age, period and cohort effects. Decomposition analysis was performed to analyze the impacts of aging, population and epidemiological change. ARIMA model was utilized for forecasting the burden of HL from 2022 to 2036.

Results

From 1990 to 2021, the number of prevalence and YLDs of HL in China rose by 125.06 and 135.13%, with an average annual percentage change of 0.19 and 0.28% for age-standardized rate (ASR) of prevalence and YLDs, respectively. Age-period-cohort analysis indicated that the risks associated with ASR of prevalence and YLDs for HL increased with age. The period effects on the ASRs of prevalence and YLDs were generally increasing (relative risk [RR] 0.98-1.06 and 0.96-1.05). Cohort effects on the risk also rising (RR 0.90-1.41 and 0.83-1.26). Aging growth accounted for the largest proportion of the increase of the number of prevalence and YLDs (68.62 and 66.39%, respectively). The prevalence and YLDs rates are expected to stabilize from 2022 to 2036, while the age-standardized prevalence rate remains above 20%. The number of people suffering from HL will reach 573.8 million, while the number of YLDs will reach 16 million.

Conclusion

The prevalent cases of HL have risen dramatically in China over the past 32 years, which expected to continue to grow by 2036, additional interventions such as enhancing primary hearing care services and boosting screening rates for HL are essential to alleviate the burden of HL, especially in the older adult population.

Nutritional Supplements for Healthy Aging: A Critical Analysis Review

Background: Healthy aging is defined as survival to advanced age while retaining autonomy in activities of daily living, high societal participation, and good quality of life. Sarcopenia, insomnia, cognitive impairment, and changes in sensation can be key hinderances to healthy aging, but nutritional supplements may abate their impact. As research advances, an updated review on their efficacy on age-related conditions is warranted. Results: Sarcopenia can be mitigated through proper protein intake, supplements like creatine, and in certain situations Branched-Chain Amino Acids and Vitamin D, in adults over 65. Melatonin supplementation has moderate evidence for improving sleep, while valerian root lacks evidence. Magnesium, tart cherry, and kiwifruits have shown promising impacts on sleep in limited articles. Magnesium, Vitamin D, and B vitamin supplementation have been shown to improve cognition in those with mild cognitive impairment and Alzheimer's disease but require further study prior to recommendation. The Age-Related Eye Disease Study supplement combination is routinely recommended to reduce risk of progression to advance stages of age-related macular degeneration. Alpha-Lipoic Acid and Folate have been investigated for their roles in mitigating age-related hearing losses. Conclusions: Nutritional supplements and lifestyle changes may mitigate disabilities across multiple domains of age-related illnesses and promote healthy aging.

Effects of cochlear implantation on gait performance in adults with hearing impairment: A systematic review

BACKGROUND

Previous systematic reviews evaluated the effect of hearing interventions on static and dynamic stability and found several positive effects of hearing interventions. Despite numerous reviews on hearing interventions and balance, the impact of cochlear implantation on gait and fall risk remains unclear.

OBJECTIVE

This systematic review examines the effects of cochlear implantation on gait performance in adults with hearing loss.

METHODS

A comprehensive literature search was conducted in PubMed, Web of Science, and Scopus, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The PEDro scale assessed the methodological quality, risk of bias, and study design of included articles.

RESULTS

Seven studies met the inclusion criteria. Five focused solely on cochlear implantation, while two included both cochlear implants (CIs) and hearing aids. Methodological inconsistencies were evident in measurement approaches and follow-up durations, leading to variable outcomes. Short-term follow-up post-implantation showed no improvement or even worsened gait outcomes. However, a longer follow-up of three months post-implantation indicated partial improvements in specific gait measures like Tandem Walk speed, though not in comfortable walking speed. Cross-sectional studies comparing on-off CI conditions revealed no significant differences in gait outcomes.

CONCLUSIONS

Improvements in gait due to cochlear implantation require at least three months to manifest. The variability in study methodologies complicates understanding the full impact of cochlear implantation on gait. Given that only seven, methodologically inconsistent articles were found, it is necessary to conduct additional research to understand the relationship between hearing, gait and fall risk and to specifically include longer post-CI monitoring periods.

RONIN/HCF1-TFEB Axis Protects Against D-Galactose-Induced Cochlear Hair Cell Senescence Through Autophagy Activation

Age-related hearing loss is characterized by senescent inner ear hair cells (HCs) and reduced autophagy. Despite the improved understanding of these processes, detailed molecular mechanisms underlying cochlear HC senescence remain unclear. Transcription Factor EB (TFEB), a key regulator of genes associated with autophagy and lysosomes, crucially affects aging-related illnesses. However, intricate regulatory networks that influence TFEB activity remain to be thoroughly elucidated. The findings revealed that RONIN (THAP11), through its interaction with host cell factor C1 (HCF1/HCFC1), modulated the transcriptional activity of Tfeb, thus contributing to the mitigation (D-galatactose [D-gal]) senescent HC loss. Specifically, RONIN overexpression improved autophagy levels and lysosomal activity and attenuated changes associated with the senescence of HCs triggered by D-gal. These findings highlight the possibility of using RONIN as a viable therapeutic target to ameliorate presbycusis by enhancing the TFEB function.

Noise exposure, hearing loss and cognitive impairment: a cross-sectional study based on an occupational health surveillance cohort in China

Background

High-intensity noise is associated with noise-induced hearing loss (NIHL). There is also evidence that noise exposure is related to cognitive impairment. This research aimed to analyze the associations and potential pathways of cumulative noise exposure (CNE), hearing loss and cognitive impairment.

Methods

A total of 560 research subjects were included in this research from May 2021 to April 2022 in western China. The demographic features, occupational features, and CNE were investigated and examined. Hearing loss was evaluated according to the National standard GB/T 7583-1987 of China. The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were used to assess cognitive function. Structural equation modeling (SEM) was used to analyze the potential pathways and specific effect sizes of CNE, hearing loss and cognitive impairment.

Results

The mean age of the research subjects was 34.3 (SD, 9.89). Men accounted for 96.4% (540/560) and women accounted for 3.6% (20/560). A total of 62.3% (349/560) held a college degree or above. The regression analysis showed that high dose CNE was related to MMSE (β = -1.069 (-1.539, -0.600)) and MoCA (β = -1.040 (-1.726, -0.355)) scores. The monaural threshold weighted value of the right ear (MTWVR) greater than 40 dB was associated with both MMSE (β = -1.183 (-2.033, -0.333)) and MoCA (β = -1.420 (-2.647, -0.193)) scores. The monaural threshold weighted value of the left ear (MTWVL) greater than 40 dB was also associated with MMSE (β = -1.540 (-2.389, -0.690)) and MoCA (β = -1.685 (-2.915, -0.456)) scores. The SEM result (Model C) showed that the standard effect of CNE- hearing loss path, CNE-MMSE path, and hearing loss-MMSE path were 0.142 (p < 0.001), -0.151 (p < 0.001), and -0.030 (p = 0.376). The Model D showed that the standard effect of CNE- hearing loss path, CNE- MoCA path, and hearing loss- MoCA path were 0.143 (p < 0.001), -0.048 (p = 0.267), and - 0.050 (p = 0.047). The CNE had only a direct effect on the MMSE score. Conversely, the CNE had only an indirect effect on the MoCA score, while hearing loss was borderline associated with MoCA. The total effects of CNE on MMSE and MoCA scores were -0.151 and -0.007, respectively.

Conclusion

Job-related noise exposure is not only associated with NIHL but also with early cognitive impairment in occupational groups. However, there is not enough evidence indicating that NLHL mediates the associations.

Special users with special needs in autonomous vehicles: A systematic review

BACKGROUND

Automated driving offers enjoyable and comfortable trips, though not everyone will find the experience pleasant. Some special populations such as elderly people, individuals with physical or cognitive impairments, and pregnant women face different difficulties in mobility services to conduct their daily activities and, consequently, also in using new technologies like autonomous vehicles.

OBJECTIVE

This study aims to review the specific needs, concerns, and difficulties of special populations when using autonomous vehicles and to highlight the primary issues affecting their acceptance of these technologies.

METHODS

A review of 48 papers was conducted to identify the special needs, concerns, and difficulties faced by various demographic groups, including elderly individuals, people with physical disabilities, and pregnant women, in using or approaching the use of autonomous vehicles.

RESULTS

The review revealed that aging individuals have received more attention by scientific community compared to other disabled populations. Acceptance of autonomous vehicles was identified as the primary issue across all surveyed groups. Safety, comfort, and dependability were also significant concerns, particularly among individuals with special needs.

CONCLUSIONS

This study outlines the unique concerns of various demographic groups using autonomous vehicles, with acceptance highlighted as a common issue. Designing user-friendly interfaces tailored to diverse demographics could enhance acceptance and improve the overall travel experience for those needing constant support.

Single-cell Transcriptomics Unravel Stereocilia Degeneration as a Key Contributor to Age-related Vestibular Dysfunction in Mice and Humans

Age-related vestibular dysfunction (ARVD) is a prevalent, debilitating condition in the elderly. The etiology and molecular mechanisms are poorly understood. We focused on mechanosensitive hair cells (HCs) as they are particularly vulnerable to aging. Using single-cell RNA-seq transcriptomes of young and old mouse vestibular HCs, we show that aging HCs display both universal molecular blueprints, such as genomic instability, mitochondrial dysfunction, and impaired proteostasis, and cell type-specific aging signatures associated with deterioration of hair bundles and mechanotransduction. These signatures are also observed in aged human vestibular HCs, suggesting shared mechanisms. Importantly, morphological and functional analysis revealed that bundle degeneration and vestibular functional decline precede HC loss, highlighting the deterioration of mechanotransduction as a key contributor to ARVD. Furthermore, molecular and cellular changes associated with aging signatures are less pronounced in vestibular HCs than in cochlear HCs, underscoring the different pace of aging between the two mammalian inner ear sensory epithelia.

Contributions and future potential of animal models for geroscience research on sensory systems

Sensory systems mediate our social interactions, food intake, livelihoods, and other essential daily functions. Age-related decline and disease in sensory systems pose a significant challenge to healthy aging. Research on sensory decline in humans is informative but can often be difficult, subject to sampling bias, and influenced by environmental variation. Study of animal models, including mice, rats, rabbits, pigs, cats, dogs, and non-human primates, plays a complementary role in biomedical research, offering advantages such as controlled conditions and shorter lifespans for longitudinal study. Various species offer different advantages and limitations but have provided key insights in geroscience research. Here we review research on age-related decline and disease in vision, hearing, olfaction, taste, and touch. For each sense, we provide an epidemiological overview of impairment in humans, describing the physiological processes and diseases for each sense. We then discuss contributions made by research on animal models and ideas for future research. We additionally highlight the need for integrative, multimodal research across the senses as well as across disciplines. Long-term studies spanning multiple generations, including on species with longer life spans, are also highly valuable. Overall, integrative studies of appropriate animal models have high translational potential for clinical applications, the development of novel diagnostics, therapies, and medical interventions and future research will continue to close gaps in these areas. Research on animal models to improve understanding of the biology of the aging senses and improve the healthspan and additional research on sensory systems hold special promise for new breakthroughs.

Upregulation of LXRβ/ABCA1 pathway alleviates cochlear hair cell senescence of C57BL/6 J mice via reducing lipid droplet accumulation

Senescence and loss of cochlear hair cells is an important pathologic basis of age-related hearing loss. Lipid droplet accumulation has previously been shown to play an important role in neurodegeneration; however, its role in age-related hearing loss has not yet been investigated. LXRβ/ABCA1 is a key pathway that regulates lipid metabolism, while its dysfunction can cause abnormal accumulation of lipid droplets in neurons, leading to neurodegeneration. In this study, we found that decreased expression of LXRβ/ABCA1, elevated levels of lipid droplet accumulation, and increased activation of the NLRP3 inflammasome were demonstrated in senescent cochlear hair cells in both animal and cellular models of age-related hearing loss. We then manipulated the LXRβ/ABCA1 pathway transduction of cochlear hair cells. Upregulation of LXRβ/ABCA1 in senescent hair cells was found to reduce the accumulation of lipid droplets, inhibit NLRP3 inflammasome activation, and ultimately alleviate cochlear hair cell senescence. In our study, we also found that NLRP3 inflammasome activation can abrogate the alleviated effect of LXRβ/ABCA1 pathway on the senescence of cochlear hair cells but did not affect the expression of LXRβ/ABCA1.Our study are the first to demonstrate that abnormal lipid droplet accumulation and decreased LXRβ/ABCA1 pathway are observed in cochlear hair cells following the occurrence of age-related hearing loss. Upregulation of LXRβ/ABCA1 in senescent cochlear hair cells can reduce lipid droplet accumulation in cochlear hair cells and alleviate their senescence, which may be related to the inhibition of NLRP3 inflammasome activation. These findings provide potential targets for the treatment of age-related hearing loss.

Development and validation of a frailty risk model for patients with mild cognitive impairment

The study aims to develop and validate an effective model for predicting frailty risk in individuals with mild cognitive impairment (MCI). The cross-sectional analysis employed nationally representative data from CHARLS 2013-2015. The sample was randomly divided into training (70%) and validation sets (30%). The least absolute shrinkage and selection operator (LASSO) and multivariable logistic regression model were used to identify independent predictors and establish a nomogram to predict the occurrence of frailty. The receiver operating characteristic (ROC) curve, the calibration curve, and the decision curve analysis (DCA) were used to evaluate the performance of the nomogram. A total of 3,196 MCI patients were analyzed, and 803 (25.1%) exhibited symptoms of frailty. Multivariate logistic regression analysis revealed that age, activities of daily living (ADL) score, depression score, grip strength, cardiovascular disease (CVD), liver disease, pain, hearing, and vision were associated factors for frailty in MCI patients. The nomogram based on these factors achieved AUC values of 0.810 (95% CI 0.780, 0.840) in the training set and 0.791 (95% CI 0.760, 0.820) in the validation set. Calibration curves showed good agreement between the nomogram and the observed values. The Hosmer-Lemeshow test results for the training and validation sets were P = 0.396 and P = 0.518, respectively. The ROC curve and decision curve analysis further validated the robust predictive ability of the nomogram. The application of this model may facilitate early clinical interventions, thereby potentially reducing the incidence of frailty among patients with MCI and significantly enhancing their long-term health outcomes.

Bioinformatics approach reveals the critical role of inflammation-related genes in age-related hearing loss

Age-related hearing loss (ARHL) is the most prevalent sensory impairment in the elderly. However, the pathogenesis of ARHL remains unclear. This study was aimed to explore the potential inflammation-related genes of ARHL and suggest novel therapeutic targets for this condition. Initially, a total of 105 Inflammatory related differentially expressed genes (IRDEGs) were obtained by overlapping the differentially expressed genes from the GSE49522 and GSE49543 datasets with Inflammatory related genes. The IRDEGs were mainly enriched in MAPK, PI3K-Akt, Hippo and JAK-STAT pathways by analysis of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. We then identified 10 key IRDEGs including Alox5ap, Chil1, Clec7a, Dysf, Fcgr3, etc. using Least absolute shrinkage and selection operator regression analysis and converted them into human genes. The ROC curve indicated that Alox5ap expression presented a high accuracy in distinguishing between different groups. By CIBERSORT algorithm, 8 humanized key IRDEGs were correlated with the infiltration abundance of 3 immune cells. Finally, it showed that the Alox5ap expression was significantly more effective compared to other variables in the diagnostic model of ARHL. This study suggests that inflammation might play a role in the development of ARHL, providing a deeper understanding of the underlying causes of this disease.

Blood Neurofilament Light Chain and Phospho-Tau 181 in Subjects with Mild Cognitive Impairment Due to Age-Related Hearing Loss

Background: Mild cognitive impairment is increasingly recognized as a precursor to more severe neurodegenerative conditions, particularly in the context of aging. Recent studies have highlighted the intersection of hearing loss and cognitive decline, suggesting that auditory deficits may exacerbate cognitive impairments in older adults, proposing the use of hearing aids to mitigate cognitive decline, and indicating that early intervention in hearing loss could be crucial for preserving cognitive function. The underlying mechanisms of the relationship between hearing and cognitive impairment may involve neuroinflammatory processes and neurodegeneration. Recent studies have evidenced the role of tau proteins and neurofilaments as biomarkers in the onset and progression of neurodegenerative diseases. Methods: We selected 30 subjects with age-related hearing loss, and we evaluated their cognitive status through the administration of screening tests, which also measured neurofilament light chain and phospho-tau 181 serum levels as biomarkers of neurodegeneration. The subjects were re-evaluated six months after the hearing aid fitting. Results: Patients with hearing impairment presented slightly altered results on cognitive tests, typical of a mild cognitive impairment. At the same time, serum levels of neurofilament light chain and phospho-tau 181 were significantly increased compared to the matched control group. After the hearing aids fitting, auditory, cognitive, and serum values results improved. Conclusions: The results of the study highlight the cognitive involvement in patients with hearing impairment and identify neurofilament light chain and phospho-tau 181 as serum biomarkers of neurodegeneration useful in monitoring the pathology.

Study in Murine Model: Is There a Relationship Between Presbycusis and Frailty?

Age-related hearing loss, or Presbycusis, is the most frequent sensory deficiency in older adults and is associated with comorbidities such as falls, cognitive decline, and frailty. Frailty is related to poor health outcomes in old age. Recent research suggested that age-related hearing loss may be a potentially modifiable risk factor for frailty, although inconclusive. The use of animal models to study the correlation between age-related hearing loss and frailty is important to test future interventions to be translated into clinical practice. The aim of this study was to determine if there is an association between age-related hearing loss and frailty in experimental animals based on the human frailty phenotype. This research studied male and female C57Bl/6J mice at different ages (6, 14, and 22 months). Auditory steady-state response threshold shifts were measured at different frequencies. To assess frailty status, we were based on the "Valence Score," which consists of measuring: weakness, weight loss, low level of activity, slowness, and little resistance. We found that hearing is significantly lower in older age groups. The mice become frail as they age. The worsening in auditory steady-state responses threshold shifts with age correlates significantly with an increasing frailty. No significant differences were found between both sexes. Our research is, to our knowledge, the first carried out in experimental animals to establish the association between age-related hearing loss and frailty, which would provide a useful tool to evaluate future interventions in mice before translating them into clinical practice.

Novel insights into mechanisms and therapeutics for presbycusis

Presbycusis, also referred to as age-related hearing loss, poses a substantial burden on both individuals and society. The hallmark of presbycusis is a progressive decrease in auditory sensitivity. Irreversible hearing loss occurs due to the limited regenerative capacity of spiral neurons and peripheral cochlear hair cells (HCs). Although hearing aids and cochlear implantations (CIs) are established approaches for alleviating symptoms of presbycusis, there are currently no preventive or curative measures available. This article provides a comprehensive discussion on the research progress pertaining to the classification, molecular mechanism, genetic susceptibility, as well as the applications and prospects of diverse therapeutic interventions of presbycusis. Building upon these discussions, promising interventions like gene therapy and stem cell (SC) therapy are proposed for their potential value in restoring cochlear function; thus aiming to pave new avenues for prevention and cure of presbycusis.

Therapeutic Effects of GDF6-Overexpressing Mesenchymal Stem Cells through Upregulation of the GDF15/SIRT1 Axis in Age-Related Hearing Loss

BACKGROUND

It has been reported the therapeutic effects of mesenchymal stem cells (MSCs) on hearing loss. This study explored the therapeutic effects of growth differentiation factor 6 (GDF6) overexpression-induced MSCs (MSCs-GDF6) on age-related hearing loss (ARHL) and its underlying mechanisms.

METHODS

Reverse transcription-quantitative PCR and western blotting were used to evaluate gene expression. Flow cytometry and immunofluorescence assays were performed for the detection of apoptosis and autophagy, respectively. Hearing function and loss of outer hair cells (HCs) in ARHL rats were measured using the auditory brainstem response and cochlear silver nitrate staining, respectively. MSC proliferation was evaluated with the Cell Counting Kit-8 assay.

RESULTS

Growth differentiation factor 15 (GDF15) and sirtuin 1 (SIRT1) expression was significantly decreased in hydrogen peroxide (H2O2)-induced House Ear Institute-Organ of Corti 1 (HEI-OC1) cells and the cochlea of ARHL rats. Elevated apoptosis and blocked autophagic flux were uncovered in H2O2-induced HEI-OC1 cells and ARHL rats. GDF15 overexpression inhibited apoptosis and restored autophagic flux in vitro and in vivo. Meanwhile, GDF15 positively regulated SIRT1 protein expression. MSCs-GDF6 not only upregulated GDF15 and SIRT1 expression but also suppressed apoptosis and restored autophagic flux to reduce loss of HCs and hearing loss in ARHL rats.

CONCLUSIONS

MSCs-GDF6 prevented loss of HCs to relieve ARHL by inhibiting apoptosis and restoring autophagic flux, likely in association with upregulation of the GDF15/SIRT1 axis.

Insignificant difference in medication adherence to dyslipidemia drugs between visually impaired and non-disabled people in South Korea: A nationwide cohort study using claims records

Incidence of visual impairment (VI) and dyslipidemia is increasing with aging. Although good medication adherence (MA) is a crucial factor in achieving therapeutic goals for dyslipidemia, there is a paucity of studies measuring MA in the visually impaired with dyslipidemia. We investigated whether patients with VI had worse MA to dyslipidemia drugs than non-disabled people and determined the factors affecting MA among patients with VI. Data on dyslipidemia patients with VI were extracted in 2017 from the sample cohort database of the National Health Insurance Service. MA to dyslipidemia drugs was measured for two years based on the proportion of days covered (PDC). Conditional logistic regression analysis was performed to analyze the effect of VI on good MA (PDC ≥0.8). The VI group (0.860) had a larger PDC than the non-disabled group (0.850). The adjusted odds ratio (aOR) for good MA among VI vs. non-disabled individuals was statistically insignificant (1.137, 95% confidence interval:0.958-1.350). Significant factors for poor MA in the VI group were younger age (aOR for 20-39 vs. ≥75 years old: 0.124), lower income (aOR for 9-10th decile (rich) vs. 1-4th decile (poor): 1.771), shorter duration of dyslipidemia (aOR for 1-4 vs. 15 years: 0.416), having lower-level providers sas their main providers (aOR for clinics vs. general/tertiary-care hospitals: 0.545), and having mental diseases (aOR: 0.679). Patients with VI did not have worse MA than non-disabled patients taking dyslipidemia medication.

Association of serum lycopene with low-frequency hearing loss in adults in their 70s based on NHANES database

Age-related hearing loss is the third most common health condition affecting elderly individuals. The relationship between lycopene in blood and sensorineural hearing loss in elderly adults has rarely been reported. This study aimed to elucidate the connection between serum lycopene levels and sensorineural hearing loss among elderly individuals. This cross-sectional study included 693 participants aged 70-80 years from the National Health and Nutrition Examination Survey (NHANES) from 2017 to 2018. The outcomes included sensorineural low-frequency hearing loss [pure-tone average (PTA) at 0.5, 1, and 2 kHz ≥ 20 dB], speech-frequency hearing loss (PTA at 0.5, 1, 2, and 4 kHz ≥ 20 dB), and high-frequency hearing loss (PTA at 4, 6, and 8 kHz ≥ 20 dB). Multivariate logistic regression analysis was used to determine the relationship between lycopene in blood and the risk of hearing loss. There were 418 (60.3%), 522 (75.3%), and 667 (96.2%) participants who experienced hearing loss at low, speech, and high frequencies, respectively. Serum total lycopene (OR = 0.575, 95% CI 0.337-0.984) and serum cis-lycopene (OR = 0.334, 95% CI 0.112-0.994) were associated with a lower risk of low-frequency hearing loss after adjusting for covariates. Among male participants, the serum total, cis-, and trans-lycopene levels were inversely related to low- and speech-frequency hearing loss. However, no relationship was observed among the female participants. In conclusion, our findings indicate that increased serum lycopene levels are associated with a decreased prevalence of sensorineural low-frequency hearing loss in older adults, especially in men.

Prevalence of hearing loss and factors associated with hearing loss in Ethiopia: findings from the 2023 National Ethiopia Hearing Survey

OBJECTIVES

To assess the prevalence and associated factors of hearing loss in Ethiopia, considering socioeconomic conditions, regional variations and age-related impacts.

DESIGN

Nationwide cross-sectional survey.

SETTING

Data were collected from 2 February to 10 June 2023, covering all regions of Ethiopia except Tigray (due to security concerns).

PARTICIPANTS

A sample of 3000 households and 7061 individuals aged 5 years and above was selected using a multistage sampling procedure. Eligible participants had resided in the area for at least 6 months. Exclusions included visitors, critically ill individuals and those with communication difficulties.

OUTCOME MEASURES

Hearing loss was defined as an average hearing threshold >20 dB in the better ear at frequencies of 0.5 kHz, 1 kHz, 2 kHz and 4 kHz, measured using pure-tone audiometry. Logistic regression analysis was performed to determine factors associated with hearing loss.

RESULTS

The overall prevalence of hearing loss among individuals aged 5+ years was 18.4%. The prevalence was 8.1% among children aged 5-14 years and 73.7% among adults aged 60+ years. Factors significantly associated with hearing loss included being over 60 years old (adjusted OR (AOR)=51.41; 95% CI 36.95, 71.53), having no formal education (AOR=2.12; 95% CI 1.47, 3.08), ear discharge (AOR=3.01; 95% CI 2.07, 4.38), wax presence (AOR=1.92; 95% CI 1.53, 2.40), and tympanic membrane abnormality (AOR=17.17; 95% CI 12.27, 24.02). Participants from the Harari (AOR=3.25; 95% CI 1.85, 5.72) and Somali (AOR=2.37; 95% CI 1.49, 3.77) regions were more likely to experience hearing loss compared with those from other regions.

CONCLUSIONS

Hearing loss is highly prevalent in Ethiopia, influenced by both modifiable and non-modifiable factors. Regional disparities in hearing loss suggest a need for targeted interventions. Evidence-based policies and strategies are essential to reduce ear diseases, improve hearing care services, and address disparities in hearing health across regions.

Association Between the Development of Sensorineural Hearing Loss and Blood NAD+ Levels

Background

Hearing loss prevalence increases with age, affecting over 25% of the global population aged 60 years or older. The aim of the study was to investigate the association between the development of sensorineural hearing loss (SNHL) and the blood levels of nicotinamide adenine dinucleotide (NAD+).

Methods

A single-center, observational study was conducted at Kawagoe Otology Institute in Japan. A total of 80 patients were included and allocated to four groups of 20 patients each: patients aged 50 - 79 years with or without unilateral sudden sensorineural hearing loss (SSNHL), and patients aged ≥ 80 years with or without bilateral age-related hearing loss (ARHL). The distribution of whole-blood NAD+ levels was investigated. We also measured oxidative stress markers (diacron-reactive oxygen metabolites (dROMs) and biological antioxidant potential (BAP)) and examined the relationship between the development of SNHL and whole-blood NAD+ levels, dROMs, and BAP.

Results

Comparison of NAD+ levels with and without hearing loss in the same age group by analysis of covariance showed a significantly lower NAD+ level in those with hearing loss than those without in the ≥ 80 age group (P = 0.047), whereas there was no difference between the two groups in the 50 - 79 age group (P = 0.232). All 80 patients, without consideration of age or type of hearing loss, were subjected to multivariate analysis to explore factors contributing to the development of hearing loss. With each 1 µM increase in the NAD+ level, the probability of developing SNHL decreased to 0.9-fold (P = 0.047), and each 1 U.CARR increase in dROMs was associated with a 1.01-fold increase in the risk of developing SNHL (P = 0.014). Whole-blood NAD+ levels in ARHL patients were significantly lower than those in non-ARHL patients. There was no association between whole-blood NAD+ and dROMs or BAP levels. This study has some limitations, including a sample size that was not large enough to detect a significant difference and an imbalance in the male-to-female ratio.

Conclusions

Decreased amount of NAD+ in the body and increased dROMs levels were associated with increased risk of developing SNHL, and the development of ARHL was especially highly associated with a decreased amount of NAD+ in the body.

Triglyceride to High-Density Lipoprotein Cholesterol Ratio and Sensorineural Hearing Loss in Community-Dwelling Adults: an NHANES Analysis

PURPOSE

Sensorineural hearing loss (SNHL) is prevalent among older adults in the United States. Recent studies suggest the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio as a potential marker for metabolic and cardiovascular conditions. Our research investigates the association between the TG/HDL-C ratio and SNHL using a comprehensive national dataset.

MATERIALS AND METHODS

This cross-sectional study utilized the National Health and Nutrition Examination Survey (NHANES) data cycle 1999-2000, 2001-2002, 2003-2004, 2011-2012, and 2015-2016. Participants aged 50-69 years with complete audiometry and TG/HDL-C data were included. The outcome was the presence of SNHL, defined as an average hearing threshold >25 dB in the better ear. We employed multivariate logistic regression adjusted for demographics, smoking, noise exposure, and comorbidities to explore the association.

RESULTS

A total of 1148 participants constituted the analytic sample, and 31.4% had SNHL. Compared to no SNHL, those with SNHL exhibited higher TG/HDL-C ratios (3.5 vs. 2.7). Elevated TG/HDL-C tertiles correlated with increased SNHL odds [tertile 2: adjusted odds ratio (aOR)=1.50, 95% confidence interval (CI): 0.97-2.32, p=0.069; tertile 3: aOR=1.64, 95% CI: 1.03-2.63, p=0.039]. The link was stronger in participants without diabetes or obesity, with significant predictive values for SNHL presence (area under the ROC curve=0.716 and 0.753, respectively).

CONCLUSION

A higher TG/HDL-C ratio was significantly associated with SNHL in US adults aged 50-69 years, especially in those free from diabetes or obesity. These findings support considering TG/HDL-C as a useful marker for SNHL risk, highlighting the importance of combined metabolic and auditory health assessments.

Age-Related Hearing Impairment: Genome and Blood Methylome Data Integration Reveals Candidate Epigenetic Biomarkers

Age-related hearing impairment (ARHI) is a major planetary health burden that is in need of precision medicine for prevention, diagnosis, and treatment. The present study was set out to identify candidate epigenetic markers for ARHI. Associations of genetically predicted DNA methylation levels with ARHI risk were evaluated using two sets of blood DNA methylation genetic prediction models in 147,997 cases and 575,269 controls of European descent. A total of 1314 CpG sites (CpGs) were significantly associated with ARHI risk at a false discovery rate (FDR) <0.05, including 12 putatively causal CpGs based on fine-mapping analysis. Measured methylation levels of 247 of the associated CpGs were significantly correlated with measured expression levels of 127 nearby genes in blood at an FDR <0.05. A total of 37 CpGs and their 18 nearby genes showed consistent association directions for the methylation-gene expression-ARHI risk pathway. Importantly, three genes (PEX6, TCF19, and SPTBN1) were enriched in auditory disease categories. Our results indicate that specific CpGs may modulate ARHI risk by regulating the expression of candidate ARHI target genes. Future precision medicine and biomarker development research on ARHI are called for.

[Is hearing perception related to the occurrence of falls among older adults during the COVID-19 pandemic? A longitudinal analysis]

This study estimated the association between hearing perception over time and the occurrence of falls among older adults during the COVID-19 pandemic. This is a longitudinal study, with data from the third wave of household interviews (2017/2019) and the fourth wave of telephone interviews from the EpiFloripa Idoso study (2021/2022), a population-based cohort with older adults aged 60 years or older, carried out since 2009 in the city of Florianópolis, state of Santa Catarina, Brazil. Fall event in the last year was the dependent variable in this study, while the perception of hearing over time was the independent variable. Logistic regression analysis was performed to identify the relation of the perception of hearing loss between the third and fourth waves of the study and the occurrence of falls. A total of 289 older adults participated in the study, mostly females (69.1%), aged 70 to 79 years (53.4%), and with 12 or more years of schooling (41%). Older adults who remained with impaired hearing were 181% more likely (OR = 2.81; 95%CI: 1.08-7.34) of falling, when compared to those without impaired hearing. In conclusion, this study results provide evidence of the association between hearing difficulty in older people and a higher chance of falls. Outcomes suggest the need for interventions aimed at auditory rehabilitation. Furthermore, an integrated and multifaceted approach is essential to mitigate the risks of falls in this age group, considering both hearing needs and fall prevention measures.

Chronic Inflammation and Age-Related Hearing: Based on Mendelian Randomization

Introduction

Age-related hearing loss (ARHL) is a degenerative condition that involves both peripheral and central auditory system pathologies. There is a close relationship between chronic inflammation and ARHL, but there is currently a lack of in-depth exploration of this relationship, particularly regarding causality.

Methods

Using age-appropriate mice for basic experiments to examine changes in central auditory nervous system inflammation, a cohort study was conducted to select relevant clinical data and observe inflammation changes in the elderly population with ARHL. Mendelian randomization was employed to investigate the causal relationship between chronic inflammation and ARHL.

Results

Clinical results indicate that CRP levels in the ARHL group are significantly higher than those in the normal group. Chronic inflammation also occurs in the auditory centers. Mendelian randomization studies provide causal evidence that genetic chronic inflammation factors do not increase the risk of ARHL.

Discussion

This article provides reliable causal evidence of the relationship between chronic inflammation and ARHL, confirming the accumulation of inflammatory factors in the auditory center, which provides a basis for the prevention and treatment of ARHL and has a good prevention prospect. However, due to the differences of research objects, this study has limitations and needs further research.

The role of cochlea extracellular matrix in age-related hearing loss

Age-related hearing loss (ARHL) is a common disease among the elderly. Although its pathogenesis remains unclear by now, it is widely accepted that ARHL is associated with the degenerative alterations within each component of the cochlea. Extracellular matrix (ECM) plays a crucial role in cochlear structure and function, providing not only structural support but also participating in vital physiological processes including the development, differentiation, survival of auditory sensory cells, and sound perception. ECM is implicated in the pathogenesis of various neurodegenerative diseases, with certain ECM proteins or associated molecules emerging as potential therapeutic targets. However, few research were carried out on ECM in the cochlea and ECM associated molecules in ARHL. This review aims to delineate the composition of ECM in the cochlea, the changes of the main ECM structure in the cochlea such as the tectorial membrane (TM), the basilar membrane (BM) and the spiral ligament (SL) during aging, as well as the role of ECM associated molecules in ARHL. We hope that this review will foster further research into ARHL.

Alzheimer's Disease: Exploring the Landscape of Cognitive Decline

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and impaired daily functioning. The pathology of AD is marked by the accumulation of amyloid beta plaques and tau protein tangles in the brain, along with neuroinflammation and synaptic dysfunction. Genetic factors, such as mutations in APP, PSEN1, and PSEN2 genes, as well as the APOE ε4 allele, contribute to increased risk of acquiring AD. Currently available treatments provide symptomatic relief but do not halt disease progression. Research efforts are focused on developing disease-modifying therapies that target the underlying pathological mechanisms of AD. Advances in identification and validation of reliable biomarkers for AD hold great promise for enhancing early diagnosis, monitoring disease progression, and assessing treatment response in clinical practice in effort to alleviate the burden of this devastating disease. In this paper, we analyze data from the CAS Content Collection to summarize the research progress in Alzheimer's disease. We examine the publication landscape in effort to provide insights into current knowledge advances and developments. We also review the most discussed and emerging concepts and assess the strategies to combat the disease. We explore the genetic risk factors, pharmacological targets, and comorbid diseases. Finally, we inspect clinical applications of products against AD with their development pipelines and efforts for drug repurposing. The objective of this review is to provide a broad overview of the evolving landscape of current knowledge regarding AD, to outline challenges, and to evaluate growth opportunities to further efforts in combating the disease.

Bats as instructive animal models for studying longevity and aging

Bats (order Chiroptera) are emerging as instructive animal models for aging studies. Unlike some common laboratory species, they meet a central criterion for aging studies: they live for a long time in the wild or in captivity, for 20, 30, and even >40 years. Healthy aging (i.e., healthspan) in bats has drawn attention to their potential to improve the lives of aging humans due to bat imperviousness to viral infections, apparent low rate of tumorigenesis, and unique ability to repair DNA. At the same time, bat longevity also permits the accumulation of age-associated systemic pathologies that can be examined in detail and manipulated, especially in captive animals. Research has uncovered additional and critical advantages of bats. In multiple ways, bats are better analogs to humans than are rodents. In this review, we highlight eight diverse areas of bat research with relevance to aging: genome sequencing, telomeres, and DNA repair; immunity and inflammation; hearing; menstruation and menopause; skeletal system and fragility; neurobiology and neurodegeneration; stem cells; and senescence and mortality. These examples demonstrate the broad relevance of the bat as an animal model and point to directions that are particularly important for human aging studies.

Understanding exogenous factors and biological mechanisms for cognitive frailty: A multidisciplinary scoping review

Cognitive frailty (CF) is the conjunction of cognitive impairment without dementia and physical frailty. While predictors of each element are well-researched, mechanisms of their co-occurrence have not been integrated, particularly in terms of relationships between social, psychological, and biological factors. This interdisciplinary scoping review set out to categorise a heterogenous multidisciplinary literature to identify potential pathways and mechanisms of CF, and research gaps. Studies were included if they used the definition of CF OR focused on conjunction of cognitive impairment and frailty (by any measure), AND excluded studies on specific disease populations, interventions, epidemiology or prediction of mortality. Searches used Web of Science, PubMed and Science Direct. Search terms included "cognitive frailty" OR (("cognitive decline" OR "cognitive impairment") AND (frail*)), with terms to elicit mechanisms, predictors, causes, pathways and risk factors. To ensure inclusion of animal and cell models, keywords such as "behavioural" or "cognitive decline" or "senescence", were added. 206 papers were included. Descriptive analysis provided high-level categorisation of determinants from social and environmental through psychological to biological. Patterns distinguishing CF from Alzheimer's disease were identified and social and psychological moderators and mediators of underlying biological and physiological changes and of trajectories of CF development were suggested as foci for further research.

Association between hearing loss and gout based on National Health and Nutrition Examination Survey and Mendelian randomization analysis

Hearing loss(HL) represents a significant public health concern. This study aimed to determine the association between hearing loss and gout and to elucidate the underlying causative mechanisms. Data for this study were obtained from the National Health and Nutrition Examination Survey (NHANES) and Mendelian randomization (MR) basic databases. Initially, baseline characteristics of individuals with and without gout were compared. A nonlinear relationship between pure tone audiometry (PTA) values and gout prevalence was confirmed through restricted cubic spline (RCS) curve analysis. Subsequently, hearing loss was categorized into different levels based on PTA values, and multiple logistic regression analysis was employed to calculate the impact of varying degrees of hearing loss on the risk of gout. Finally, MR analysis was conducted to further elucidate the causal relationship between hearing loss and gout. A total of 3,258 individuals were included in this study, with a gout prevalence of 3.7%. Significant differences were observed between the gout group and the non-gout group in variables such as age, gender, blood uric acid level, BMI, hypertension, and diabetes. RCS curve analysis revealed a significant nonlinear relationship between PTA values and gout risk, particularly when PTA values exceed a specific threshold, where the curve flattens. Based on different levels of hearing loss derived from PTA values, multiple logistic regression analysis demonstrated that mild and moderate hearing loss significantly increased the risk of gout, remaining statistically significant after adjusting for covariates (odds ratio (OR) = 2.10-3.48, P < 0.05). MR analysis further confirmed the causal relationship between hearing loss and gout. Inverse variance weighting (IVW) was employed as the primary method, revealing that both individuals with hearing difficulties (OR = 0.98, 95% confidence interval (CI) 0.96-0.999, P = 0.012) and those without hearing impairment (OR = 1.02, 95% CI 1.01-1.04, P = 0.012) exhibited a significant causal relationship with gout. Goodness-of-fit tests and sensitivity analyses were used to verify the reliability of the results. Hearing loss has a significant causal relationship with an increased risk of gout, providing a new perspective for the prevention and management of gout. Focused attention and prompt treatment of hearing loss, particularly mild and moderate hearing loss, may significantly reduce the risk of developing gout.

Causal linkage of Graves' disease with aging: Mendelian randomization analysis of telomere length and age-related phenotypes

BACKGROUND

Aging is an irreversible progressive decline in physical function. Graves' disease (GD) is a common cause of hyperthyroidism and is characterized by elevated levels of the thyroid hormone (TH). High TH levels are associated with aging and a shortened lifespan. The causal relationship between GD and aging has yet to be investigated.

METHODS

We used genome-wide association study (GWAS) datasets and Mendelian randomization (MR) analysis to explore the causal link between GD and aging. To assess the statistical power of instrumental variables (IVs), F-statistics and R2 were used. MR analysis was conducted using inverse-variance weighting (IVW), MR-Egger, weighted median, and weighted mode. The odds ratio (OR) and 95% CI were calculated to estimate the relative risk of GD to the outcomes. The Cochran Q test, I2, MR-PRESSO test, and MR-Egger regression intercept were calculated using statistical and leave-one-out analyses to test the heterogeneity, horizontal pleiotropy, and stability of the IVs on the outcomes.

RESULTS

F-statistics of the five IVs were greater than 10, and the R2 values ranged from 0.033 to 0.156 (R2 > 0.01). According to the results of the IVW analysis, GD had no causal effect on facial aging (p = 0.189), age-related macular degeneration (p = 0.346), and Alzheimer's disease (p = 0.479). There was a causal effect of GD on the remaining outcomes: telomere length (TL) (OR = 0.982; 95%CI:0.969-0.994; p = 0.004), senile cataract (OR = 1.031; 95%CI:1.002-1.060; p = 0.033), age-related hearing impairment (OR = 1.009; 95%CI:1.004-1.014; p = 0.001), chronic obstructive pulmonary disease (COPD) (OR = 1.055; 95%CI:1.008-1.103; p = 0.020), and sarcopenia (OR = 1.027; 95%CI:1.009-1.046; p = 0.004).

CONCLUSIONS

GD accelerates the occurrence of age-related phenotypes including TL, senile cataracts, age-related hearing impairment, COPD, and sarcopenia. In contrast, there are no causal linkages between GD and facial aging, age-related macular degeneration, or Alzheimer's disease. Further experimental studies could be conducted to elucidate the mechanisms by which GD facilitates aging, which could help slow down the progress of aging.

Age-Related Increase in Type C Tympanogram

Background: This study evaluated the relationship between aging and tympanometric changes, specifically the incidence of type C tympanograms, using data from the Korea National Health and Nutrition Examination Survey (KNHANES). Methods: We analyzed data from the 2019-2022 KNHANES, including 26,738 ears from individuals aged 40 and older. Tympanometry at 226 Hz identified type C tympanograms based on peak pressure below -100 daPa. Multiple logistic regression evaluated the association between age and type C tympanograms, adjusting for confounders such as sex, smoking status, allergic rhinitis, chronic sinusitis, and lifestyle disease markers. Results: The incidence of type C tympanograms increased significantly with age (R2 = 0.953, p < 0.001). Age was the most significant factor associated with type C tympanograms (p < 0.001, odds ratio 1.052), while other factors were not statistically significant. Ears with type C tympanograms had significantly poorer hearing thresholds compared to those with type A tympanograms (p < 0.001). Conclusions: Aging is significantly associated with an increased incidence of type C tympanograms, indicating possible middle ear dysfunction in older adults. The correlation between type C tympanograms and poorer hearing thresholds suggests that age-related changes in middle ear function may contribute to hearing impairment. Tympanometric screening in older adults may facilitate early detection and management of middle ear dysfunction, potentially improving hearing outcomes and quality of life.

Impact of hearing rehabilitation programs on presbycusis management: a systematic review and meta-analysis of randomized controlled trials

Background

In the field of audiology, numerous studies have sought to understand and improve hearing rehabilitation programs for older adults afflicted with presbycusis. Despite this, the field lacks uniform standards pertaining to the intervention methods, frequency, and duration of such programs. These discrepancies have led to varying test results and inconsistent findings across multiple studies.

Objective

This meta-analysis aimed to evaluate the efficacy of hearing rehabilitation programs in enhancing the utilization of hearing aids among older adults with presbycusis.

Methods

We conducted a comprehensive exploration of PubMed, Embase, Cochrane Library, and Web of Science to identify randomized controlled trials assessing the role of hearing rehabilitation programs for patients with age-related hearing loss. The search period spanned from the inception of each database to September 12, 2024. Outcomes were synthesized using RevMan 5.4 software.

Results

Eight studies met the inclusion criteria, involving 598 patients (290 in the intervention group and 308 in the control group). It was observed that hearing rehabilitation programs significantly diminished self-perceived hearing impairment [MD = -5.80, 95% CI = (-8.16, -3.44), p < 0.00001] and negative emotional states [MD = -1.66, 95% CI = (-3.02, -0.29), p = 0.02], while enhancing hearing aid utilization [MD = 0.22, 95% CI = (0.08, 0.36), p = 0.002]. Nonetheless, these programs did not significantly augment patients' satisfaction with their hearing aids [MD = 0.09, 95% CI = (-0.17, 0.26), p = 0.66].

Conclusion

Hearing rehabilitation programs significantly improve hearing aid outcomes, reduce self-perceived hearing impairment, and alleviate negative emotional states in patients. However, the current body of evidence is insufficient to conclusively indicate that these programs enhance patient satisfaction with daily hearing aid usage.

Dynamic micro-optical coherence tomography enables structural and metabolic imaging of the mammalian cochlea

Sensorineural hearing loss (SNHL) is caused by damage to the mechanosensory hair cells and auditory neurons of the cochlea. The development of imaging tools that can directly visualize or provide functional information about a patient's cochlear cells is critical to identify the pathobiological defect and determine the cells' receptiveness to emerging SNHL treatments. However, the cochlea's small size, embedded location within dense bone, and sensitivity to perturbation have historically precluded high-resolution clinical imaging. Previously, we developed micro-optical coherence tomography (μOCT) as a platform for otologic imaging in animal models and human cochleae. Here we report on advancing μOCT technology to obtain simultaneously acquired and co-localized images of cell viability/metabolic activity through dynamic μOCT (DμOCT) imaging of intracellular motion. DμOCT obtains cross-sectional images of ATP-dependent movement of intracellular organelles and cytoskeletal polymerization by acquiring sequential μOCT images and computing intensity fluctuation frequency metrics on a pixel-wise basis. Using a customized benchtop DμOCT system, we demonstrate the detailed resolution of anatomical and metabolic features of cells within the organ of Corti, via an apical cochleostomy, in freshly-excised adult mouse cochleae. Further, we show that DμOCT is capable of capturing rapid changes in cochlear cell metabolism following an ototoxic insult to induce cell death and actin stabilization. Notably, as few as 6 frames can be used to reconstruct cochlear DμOCT images with sufficient detail to discern individual cells and their metabolic state. Taken together, these results motivate future development of a DμOCT imaging probe for cellular and metabolic diagnosis of SNHL in humans.

Healthcare Professionals' Knowledge, Skills, and Information Needs Pertaining to Hearing Loss and Hearing Aids in Swedish Nursing Homes: A Cross-Sectional Study and Psychometric Evaluation

Background

Hearing loss increases with age and due to increased life expectancy there is an increase in the number of individuals living with hearing loss. Older people with hearing loss residing in nursing homes are often dependent on healthcare professionals to help them with their hearing aids.

Objective

The aim of the study was to translate and test the psychometric properties of a Swedish version of a Norwegian questionnaire and to assess healthcare professionals' self-reported knowledge, experience, skills, competence, and information needs pertaining to residents' hearing loss and hearing aids in the Swedish context.

Materials and Methods

A Norwegian questionnaire was translated and adapted, and thereafter distributed to healthcare professionals in nine nursing homes in mid Sweden between 2020 and 2021, and 313 questionnaires were returned.

Results

An exploratory factor analysis demonstrated adequate factorial structure in six factors, satisfying construct validity and internal consistency for the Swedish version. A confirmatory factor analysis showed a satisfactory model fit. Healthcare professionals reported having the skills required for handling hearing aids, but reported lower scores for having received information about hearing aids, taking initiatives to refer residents to hearing healthcare units, and checking for earwax. Registered nurses generally reported lower perceived knowledge and practical skills concerning hearing aids. Seventy-seven percent of the total group reported a need for information regarding hearing aid maintenance.

Conclusion

Healthcare professionals reported that the majority of nursing home residents need help with their hearing aids, but only a minority of these professionals had received education on hearing loss and training in hearing aid maintenance. Enrolled nurses and care assistants demonstrated higher levels of competence in handling hearing aids compared to registered nurses. In order to ensure safe and effective care, as well as facilitate communication among older adults with hearing loss, healthcare professionals need appropriate education and training.

Sestrin2 plays a protective role in age-related hearing loss by inhibiting NLRP3-inflammasome activity

Age-related hearing loss (ARHL) is an auditory disease characterized by gradual loss of high-frequency hearing sensitivity. Excessive reactive oxygen species trigger NLRP3-inflammasome activation that may be crucial for ARHL pathogenesis. The antioxidant factor Sestrin2 (SESN2) has been reported to be involved in the remission of oxidative stress and ARHL. However, the mechanism by which SESN2 protects auditory cells in the aging mouse cochlea remains unknown. Here, we observed that ectopic overexpression of SESN2 delayed ARHL, whereas SESN2 knockdown accelerated it. Importantly, we elucidated that SESN2 exerts a hearing-protective effect by inhibiting the production of NLRP3 by acting as a mitophagy agonist. Our study proposes a new theoretical basis for SESN2 prevention of ARHL and provides a novel therapeutic strategy for maintaining SESN2 activity in the aging cochlea.

Relationship between hearing loss and depression: A cross-sectional analysis from the National Health and Nutrition Examination Survey 2015-2018

BACKGROUND

Hearing loss is a prevalent issue resulting from loud noise exposure, aging, diseases, and genetic differences. As individuals age, the likelihood of experiencing hearing loss and depression escalates; yet, the link between hearing loss and the risk of depression remains ambiguous. This study explores the relationship between hearing and depression risk, taking into account sociodemographic and health-related factors.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES) 2015-2018, a cross-sectional analysis was conducted, focusing on adult participants. It evaluated their hearing status and depression levels using the Patient Health Questionnaire-9 (PHQ-9). The study examined a range of variables, such as age, gender, socioeconomic status, lifestyle choices, and comorbidities, to understand their influence on the link between hearing loss and depression.

RESULTS

Analysis indicated a significant association between moderate to severe hearing loss and an increased risk of depression, notably in older adults. This relationship remained significant even after adjusting for a variety of sociodemographic and health factors.

LIMITATIONS

This is a study using the NHANES database using self-reported surveys.

CONCLUSION

The findings of this study emphasize the need to integrate hearing health in the holistic assessment and treatment of depression, particularly advocating for combined care strategies for the elderly.