The crucial role of diverse animal models to investigate cochlear aging and hearing loss

Age-related hearing loss affects a large and growing segment of the population, with profound impacts on quality of life. Age-related pathology of the cochlea-the mammalian hearing organ-underlies age-related hearing loss. Because investigating age-related changes in the cochlea in humans is challenging and often impossible, animal models are indispensable to investigate these mechanisms as well as the complex consequences of age-related hearing loss on the brain and behavior. In this review, we advocate for a comparative and interdisciplinary approach while also addressing the challenges of comparing age-related hearing loss across species with varying lifespans. We describe the experimental advantages and limitations as well as areas for future research in well-established models of age-related hearing loss, including mice, rats, gerbils, chinchillas, and birds. We also indicate the need to expand characterization of age-related hearing loss in other established animal models, especially guinea pigs, cats, and non-human primates, in which auditory function is well characterized but age-related cochlear pathology is understudied. Finally, we highlight the potential of emerging animal models for advancing our understanding of age-related hearing loss, including deer mice, with their notably extended lifespans and preserved hearing, naked mole rats, with their exceptional longevity and extensive vocal communications, as well as zebrafish, which offer genetic tractability and suitability for drug screening. Ultimately, a comparative and interdisciplinary approach in auditory research, combining insights from various animal models with human studies, is key to robust and reliable research outcomes that better advance our understanding and treatment of age-related hearing loss.

Use of the traditional Chinese medicine "compound healthy ear agent" to protect against age-related hearing loss in mice: A proteomics study

Background

Previous studies have shown that the traditional Chinese medicine (TCM) called "compound healthy ear agent" (CHEA) had anti-apoptosis effects in cochlear hair cells and spiral ganglion neurons, and could protect mice hearing against presbycusis or age-related hearing loss (AHL), as well as aminoglycoside antibiotic-induced ototoxicity. Because its mechanisms of action are still unclear, we investigated the mechanism of action of CHEA against AHL in mice using proteomics techniques.

Methods

Eighteen C57BL/6J mice at 1 month of age were randomly divided into three groups: (A) drinking water until 2 months of age, K2M); (B) drinking water until 7 months of age to induce AHL, K7M; (C) drinking water containing CHEA daily until 7 months of age as treatment group, Z7M. At 2 or 7 months mice were sacrificed and their cochleae were removed for proteomics analysis.

Results

The numbers of proteins with a false discovery rate (FDR) < 1% were respectively 5873 for qualitative and 5492 for quantitative statistics. The numbers of proteins with differential enrichment at least 1.5-fold (p < 0.05) were respectively 351 for K7M vs K2M groups, 52 for Z7M vs K7M groups, 264 for Z7M vs K2M groups. The differentially expressed proteins in the Z7M group were involved in synaptic molecular transmission, energy metabolism, immune response, antioxidant defenses, and anti-apoptosis.

Conclusion

The TCM CHEA played a protective role against AHL in mice by regulating the expression of specific proteins and genes in cochlear hair cells and spiral ganglion neurons. Besides the pathways expected to be involved (antioxidant and anti-apoptosis), proteins related to immune response is a new finding of the present study.

The reverse stethoscope technique: a rapid intervention for old age hearing loss

OBJECTIVES

Presbycusis is highly prevalent, affecting between a third and two-thirds of elderly populations. Effective communication between patient and physician has been shown to directly correlate with the quality of patient care. The Reverse Stethoscope Technique (RST) involves placing the earpieces into the patient's ears and speaking into the diaphragm. Here, we aim to show the RST is a simple and effective method to communicate with patients suffering from presbycusis in inpatient settings.

METHODS

Medical inpatients aged >60 years old without cognitive impairment were included in the study. A simple repetition exercise of basic English sentences was performed with and without the RST to assess hearing ability. Patients then undertook a short questionnaire.

RESULTS

Our study included 109 patients with varied 'self-reported' hearing. 50.5% of our cohort reported past communication difficulties with health-care professionals due to hearing difficulties. We identified that the RST increased the mean number of sentences a patient could repeat from 2.6 to 3.5 representing a statistically significant increase (p < 0.001). The technique was most beneficial for patients with 'okay' and 'poor' hearing. The majority of patients (77/109) also stated the technique reduced background noise. The RST was equally effective with facemasks.

CONCLUSION

Current techniques to enhance communication with patients with hearing loss are often underutilized or poorly accessible. Our study identified that the RST is a quick and effective solution that can be easily implemented for patients struggling to communicate with health-care professionals in inpatient scenarios.

Patient-healthcare provider communication and age-related hearing loss: a qualitative study of patients' perspectives

BACKGROUND

The prevalence of age-related hearing loss (ARHL) significantly increases in people aged 60 and older. Medical errors are frequently reported because of communication breakdown, especially for patients with ARHL.

AIMS

This qualitative study focuses on identifying the communication challenges faced by people aged over 65 with ARHL and potential ameliorative strategies based on the participants' personal experiences.

METHODS

Thirteen participants, attending a support service for older adults with hearing loss in the South of Ireland, were recruited using convenience sampling. Semi-structured interviews were conducted with participants. Interviews were audio-recorded and transcribed using NVivo 12 software. Braun and Clarke's thematic analysis methodology was used to identify themes arising from two main study domains: difficulties faced during the most recent healthcare interaction and suggestions for improving overall healthcare communication.

RESULTS

Older adults with hearing loss identified general mishearing, lack of awareness and use of medical terminology to be the cause of ineffective communication. Raising awareness of the impact of presbycusis on clinical interaction among healthcare professionals was cited as being of crucial importance. Other helpful strategies include repeat and rephrase, use of written information, providing context, minimizing ambient noise, continuity of care, longer consultation length and good body language.

CONCLUSION

Effective clinical communication can be achieved through a clear understanding of the patient's perspective. Healthcare providers should be made aware of the hearing issues and associated communication difficulties posed, within the context of the development of patient-centred strategies to improve patient safety.

Age-related hearing loss: An updated and comprehensive review of the interventions

Aging causes progressive degenerative changes in many organs, particularly the auditory system. Several attempts have been conducted to investigate preventive and therapeutic strategy/strategies for age-related auditory dysfunction, such as maintaining a healthy lifestyle through good nutrition, lower anxiety levels, and noise exposure, different pharmacological approaches, gene and cell therapy, and other strategies. However, it is not clear which approach is the best to slow down these dysfunctions because several different underlying mechanistic pathways are associated with presbycusis which eventually leads to different types of this disease. A combination of several methods is probably required, whereas the effectiveness for some people needs to be monitored. The effectiveness of treatments will not be the same for all; therefore, we may need to have a unique and personalized approach to the prevention and treatment of ARHL for each person. In addition, each method needs to specify what type of presbycusis can prevent or treat and provide complete information about the extent, duration of treatment, persistency of treatment, side effects, and whether the approach is for treatment or prevention or even both. This paper reviews the updated literature, which targets current interventions for age-related hearing loss.

Association Between Hearing Level and Mental Health and Quality of Life in Adults Aged >40 Years

BACKGROUND AND OBJECTIVES

In this study, we investigated the effects of hearing loss on mental health and quality of life (QoL) using survey data in adults aged >40 years. Subjects and.

METHODS

We obtained data from 10,921 individuals who responded to the fifth Korean National Health and Nutrition Examination Survey. Primary outcomes were measured using questionnaires that recorded stress perception, depressive mood, and suicidal ideation to evaluate mental health and motor ability, self-management, activities of daily living, pain or discomfort, and anxiety or depression to evaluate QoL.

RESULTS

On multivariate analysis, suicidal ideation was more prevalent among older adults with hearing loss than in older adults without hearing loss. Motor ability was lower in individuals with hearing loss of >20 dB than in older adults with normal hearing. Categorization of the EuroQol-5 Dimension (EQ-5D) health state into upper and lower groups showed that the EQ-5D values were lower in the moderate-tosevere hearing loss group than in the mild hearing loss group.

CONCLUSIONS

Among adults aged >40 years, those with hearing loss experienced more suicidal ideation, had lower motor ability, and lower overall QoL compared with these variables in older adults with normal hearing. Additionally, QoL scores were low in individuals with poor hearing.

Genetic analysis of potential biomarkers and therapeutic targets in age-related hearing loss

Age-related hearing loss (ARHL) or presbycusis is the phenomenon of hearing loss due to the aging of auditory organs with age. It seriously affects the cognitive function and quality of life of the elderly. This study is based on comprehensive bioinformatic and machine learning methods to identify the critical genes of ARHL and explore its therapy targets and pathological mechanisms. The ARHL and normal samples were from GSE49543 datasets of the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was applied to obtain significant modules. The Limma R-package was used to identify differentially expressed genes (DEGs). The 15 common genes of the practical module and DEGs were screened. Functional enrichment analysis suggested that these genes were mainly associated with inflammation, immune response, and infection. Cytoscape software created the protein-protein interaction (PPI) layouts and cytoHubba, support vector machine-recursive feature elimination (SVM-RFE), and random forests (RF) algorithms screened hub genes. After validating the hub gene expressions in GSE6045 and GSE154833 datasets, Clec4n, Mpeg1, and Fcgr3 are highly expressed in ARHL and have higher diagnostic efficacy for ARHL, so they were identified as hub genes. In conclusion, Clec4n, Mpeg1, and Fcgr3 play essential roles in developing ARHL, and they might become vital targets in ARHL diagnosis and anti-inflammatory therapy.

D-Galactose and Hypoxia Induce the Early Onset of Age-Related Hearing Loss Deterioration in a Mouse Model

BACKGROUND

We previously showed that aging accelerates after 3 months of exposure to hypoxia and environmental change but not genetic modifications. Here, we aimed to simply induce early-onset age-related hearing loss within a short period based on our previous method.

METHODS

We randomly divided 16 C57BL/6 mice into four groups that were maintained under conditions of normoxia and hypoxia with or without injected D-galactose for 2 months. Deteriorated hearing, the expression of age-related factors, and oxidative stress responses were detected using the click and tone burst auditory brainstem response test, reverse transcription-polymerase chain reaction, and by measuring superoxide dismutase (SOD).

RESULTS

The group maintained under hypoxia combined with D-galactose lost hearing particularly at 24 Hz and 32 Hz at 6 weeks compared with the other groups. Aging-related factors were also significantly decreased in the hypoxia and D-galactose groups. However, SOD levels did not significantly differ among the groups.

CONCLUSION

Age-related hearing loss is an environmental disorder induced by chronic oxidative stress associated with genetic backgrounds. Our findings suggested that D-galactose and hypoxia can induce the phenotypes of age-related hearing loss and aging-associated molecules in a murine model within a short time with environmental stimulation alone.

Spatio-temporal pattern of c-Jun N-terminal kinase isoforms in the cochleae of C57BL/6J mice with presbycusis

The c-Jun N-terminal kinase (JNK) pathway is a vital component of the mitogen-activated protein kinase cascade, which regulates cell death and survival. The present study aimed to explore the Spatio-temporal changes in all JNK isoforms in the cochleae of C57/BL6J mice with age-related hearing loss. Changes in the three isoforms of JNKs in the cochleae of an animal model with presbycusis and the senescent HEI-OC1 cell line were tested by immunohistochemistry staining and western blotting. Our results demonstrated that all three JNK isoforms are distributed in the cochleae, and the expression patterns of JNK1, JNK2, and JNK3 differed in hair cells, spiral ganglion neurons, and stria vascularis, with great significance in the cochleae of adult C57BL/6J mice. The levels of JNK1, JNK2, and JNK3 showed various spatio-temporal changes in the aging mice. In a senescent hair cell model, changes in JNK1, JNK2, and JNK3 expression levels were similar to those observed in the cochleae. Our study is the first to show that JNK3 is highly expressed in the hair cells of C57BL/6J mice and further increases in conjunction with age-related hearing loss, suggesting that it may play a more critical role than previously believed in hair cell loss and spiral ganglion degeneration.

Bibliographical review of ethiopathogenic aspects, consequences on quality of life and positive effects of its treatment

At this time, we still do not have adequate knowledge and awareness of the consequences of hearing loss in the elderly on quality of life. Similarly, there is also insufficient information on the relationship of presbycusis and balance disorders with other comorbidities. Such knowledge can contribute to improve both prevention and treatment of these pathologies, to reduce their impact on other areas such as cognition or autonomy, as well as to have more accurate information on the economic impact they generate in society and in the health system. Therefore, with this review article we aim to update the information on the type of hearing loss and balance disorders in people over 55 years of age, and their associated factors; to analyze the impact on the quality of life of these people and the one which can be generated at a personal and population level (both sociological and economic) if an early intervention in these patients is pursued.

Noise-induced auditory damage affects hippocampus causing memory deficits in a model of early age-related hearing loss

Several studies identified noise-induced hearing loss (NIHL) as a risk factor for sensory aging and cognitive decline processes, including neurodegenerative diseases, such as dementia and age-related hearing loss (ARHL). Although the association between noise- and age-induced hearing impairment has been widely documented by epidemiological and experimental studies, the molecular mechanisms underlying this association are not fully understood as it is not known how these risk factors (aging and noise) can interact, affecting memory processes. We recently found that early noise exposure in an established animal model of ARHL (C57BL/6 mice) accelerates the onset of age-related cochlear dysfunctions. Here, we extended our previous data by investigating what happens in central brain structures (auditory cortex and hippocampus), to assess the relationship between hearing and memory impairment and the possible combined effect of noise and sensory aging on the cognitive domain. To this aim, we exposed juvenile C57BL/6 mice of 2 months of age to repeated noise sessions (60 min/day, pure tone of 100 dB SPL, 10 kHz, 10 consecutive days) and we monitored auditory threshold by measuring auditory brainstem responses (ABR), spatial working memory, by using the Y-maze test, and basal synaptic transmission by using ex vivo electrophysiological recordings, at different time points (1, 4 and 7 months after the onset of noise exposure, corresponding to 3, 6 and 9 months of age). We found that hearing loss, along with accelerated presbycusis onset, can induce persistent synaptic alterations in the auditory cortex. This was associated with decreased memory performance and oxidative-inflammatory injury in the hippocampus, the extra-auditory structure involved in memory processes. Collectively, our data confirm the critical relationship between auditory and memory circuits, suggesting that the combined detrimental effect of noise and sensory aging on hearing function can be considered a high-risk factor for both sensory and cognitive degenerative processes, given that early noise exposure accelerates presbycusis phenotype and induces hippocampal-dependent memory dysfunctions.

Association between Sleep Duration and Presbycusis in Korean Adults: Korea National Health and Nutrition Examination Survey

BACKGROUND

Sleep duration is associated with hearing loss, especially presbycusis, which is the most common type of hearing loss; however, there is limited evidence regarding this association among the Korean population. We aimed to determine the relationship between sleep duration and high-frequency hearing loss in Korean adults aged ≥40 years.

METHODS

We examined 5,547 Korean adults aged ≥40 years who completed audiometric tests and questionnaires regarding sleep duration during the 2010-2012 cycle of the Korea National Health and Nutrition Examination Survey. Mild presbycusis was defined as >25 decibels (dB) and <40 dB, whereas moderate-to-severe presbycusis was defined as >40 dB pure tone averages at high frequencies (3,000, 4,000, and 6,000 Hz) for both ears. Additionally, the sleep duration was divided into quartiles. Odds ratios and 95% confidence intervals were estimated using multivariable logistic regression after adjusting for covariates.

RESULTS

The prevalence of presbycusis in South Korean adults was 62.1%, of which 61.4% showed moderate to severe presbycusis. The incidence of moderate-to-severe, but not mild, presbycusis showed a significant positive correlation with sleep duration.

CONCLUSION

Our findings suggest that sleep duration is associated with the prevalence of presbycusis.

Neurochemical and functional reorganization of the cognitive-ear link underlies cognitive impairment in presbycusis

Recent studies suggest that the interaction between presbycusis and cognitive impairment may be partially explained by the cognitive-ear link. However, the underlying neurophysiological mechanisms remain largely unknown. In this study, we combined magnetic resonance spectroscopy (MRS) and resting-state functional magnetic resonance imaging (fMRI) to investigate auditory gamma-aminobutyric acid (GABA) and glutamate (Glu) levels, intra- and inter-network functional connectivity, and their relationships with auditory and cognitive function in 51 presbycusis patients and 51 well-matched healthy controls. Our results confirmed reorganization of the cognitive-ear link in presbycusis, including decreased auditory GABA and Glu levels and aberrant functional connectivity involving auditory networks (AN) and cognitive-related networks, which were associated with reduced speech perception or cognitive impairment. Moreover, mediation analyses revealed that decreased auditory GABA levels and dysconnectivity between the AN and default mode network (DMN) mediated the association between hearing loss and impaired information processing speed in presbycusis. These findings highlight the importance of AN-DMN dysconnectivity in cognitive-ear link reorganization leading to cognitive impairment, and hearing loss may drive reorganization via decreased auditory GABA levels. Modulation of GABA neurotransmission may lead to new treatment strategies for cognitive impairment in presbycusis patients.

Association between age-related hearing loss and gait disorders in older fallers

INTRODUCTION

Falls are associated with hearing loss, which might be explained by the onset of gait disorders. The objective of this study was to examine the association between Age-Related Hearing Loss (ARHL) and gait disorders assessed with GAITrite^® walkway in a population of fallers aged 75 and over while accounting for the vestibular function.

METHODS

We examined data from 53 older patients (mean 84.2 ± 5.1 years; 64% women) included after a GAITrite^® walkway assessment together with hearing and vestibular tests. People with high-frequency hearing loss, higher than 10% of the age and sex-matched population with the worst hearing, composed untimely ARHL group (n = 30), whereas all others had expected ARHL (n = 23). Presbyvestibulopathy was assessed accordingly to Barany Society criteria.

RESULTS

After adjustment for age, sex, body mass index, Mini-Mental State Examination score and presbyvestibulopathy, we found an increase in stride length mean in the untimely ARHL group (p = 0.046), but no between-group differences in stride length variability, cadence or velocity. Untimely ARHL was not associated with presbyvestibulopathy.

CONCLUSIONS

Untimely ARHL in older fallers was not associated with gait disorders in the studied population.

Cognitive, physical, and mental profiles of older adults with misplaced self-evaluation of hearing loss

BACKGROUND

Although inconsistency between objective and subjective hearing loss among older adults has been suggested, a systematic examination of the cognitive and physical functioning among such older adults is lacking. Our objective was to assess the cognitive, physical, and mental profiles associated with the discrepancy.

METHODS

The auditory acuity of 696 community-dwelling older adults was evaluated using a pure-tone average of hearing thresholds at 1.0 and 4.0 kHz in the better-hearing ear. Participants were then stratified as follows: normal hearing ≤ 25 dB, mild loss >25 dB and ≤40 dB, and moderate loss >40 dB and ≤70 dB. Global cognition, gait speed, and depressive symptoms were also assessed.

RESULTS

Among older adults, 63.5% of those with mild hearing loss and 22.2% of those with moderate hearing loss did not recognize hearing difficulties. Significantly lower cognition and gait performance were observed in those with moderate hearing loss without subjective hearing loss (i.e., overestimation of hearing acuity) than in those with subjective hearing loss. Furthermore, older adults with subjective hearing loss showed a higher tendency toward depression than those without subjective hearing loss, irrespective of objective hearing loss.

CONCLUSIONS

Our results suggest that failure to recognize a high level of age-related hearing loss may be related to impaired cognition and gait performance among older adults. Subjective hearing loss may indicate a tendency toward depression.

Global characteristics and trends of presbycusis research from 2002 to 2021: a bibliometric study

BACKGROUND AND OBJECTIVE

Age-related hearing loss, also termed presbycusis, is the most prevalent sensory impairment in older adults. Presbycusis research has considerably advanced over the past few decades, however, comprehensive and objective reports on the current state of presbycusis research are lacking. We used bibliometric methods to objectively analyzed the progress of presbycusis research over the past 20 years and to identify the research hotspots and emerging trends in this field.

METHODS

Eligible literature metadata published between 2002 and 2021 were obtained from the Web of Science Core Collection on September 1, 2022. Bibliometric tools including CiteSpace, VOSviewer, Bibliometrix R Package, Microsoft Excel 2019, and an online bibliometric platform were used to conduct bibliometric and visualized analyses.

RESULTS

A total of 1,693 publications related to presbycusis were retrieved. The number of publications increased continuously from 2002 to 2021, and the USA occupied the lead position in the field, with the highest research output. The most productive and influential institution, author, and journal were the University of California, Frisina DR of the University of South Florida, and Hearing Research, respectively. Co-citation cluster and trend topics analyses revealed that "cochlear synaptopathy", "oxidative stress", and "dementia" were the predominant foci of presbycusis research. Burst detection of keywords indicated that "auditory cortex" and "Alzheimer's disease" were the newly-emerged aspects.

CONCLUSION

During the past two decades, presbycusis research has been flourishing. The current research foci are "cochlear synaptopathy", "oxidative stress", and "dementia". "Auditory cortex" and "Alzheimer's disease" may be potential future directions in this field. This bibliometric analysis represents the first quantitative overview of presbycusis research, thus providing valuable references and insights for scholars, medical practitioners, and policymakers concerned with this field.

Hearing aid use and gender differences in the auditory-cognitive cascade in the oldest old

OBJECTIVES

This study analyzed cognitive differences between hearing-aid (HA) and non-HA users. We hypothesized that HA-use attenuates the auditory-cognitive cascade, thereby, the latter is more conspicuous in non-HA users. Since hearing impairment (HI) shows male predominance, we hypothesized gender differences within the auditory-cognitive relationship.

METHODS

Non-frail community-dwellers ≥ 80 years were assessed for HI (pure tone audiogram-PTA; speech reception threshold-SRT) and global and domain-specific cognitive impairments (Mini-Mental State Examination-MMSE; Montreal Cognitive Assessment-MOCA; Reaction Time Test-RT1-4). Pearson and partial correlations (correcting for age and PTA) assessed auditory-cognitive associations within gender and HA subgroups. Fisher's z test compared correlations between HA and non-HA users.

RESULTS

126 participants (age range 80-91 years) were included. HA-use prevalence was 21%. HA-users were older with worse HI (mean PTA 49.5dBHL). HA-users exhibited no significant auditory (PTA, SRT) and cognitive (MMSE, MOCA, RT1- RT4) correlations. Male non-HA users, displayed a significant association between HI and global cognition, processing speed, selective and alternating attention. Significant differences were noted between MMSE and PTA and SRT (z-score 2.28, 3.33, p = 0.02, <0.01, respectively) between HA and non-HA users.

CONCLUSION

Male non-HA users displayed an association between HI and global and domain-specific (processing speed; selective and alternating attention) cognitive decline. Associations between global cognition and HI were significantly different between HA and non-HA users. This may be partially attributable to underlying subgroups sample sizes and statistical power disparity. If larger scale longitudinal or interventional studies confirm these findings, timely HI assessment and management may be the cornerstone for delaying cognitive decline.

Physiological Evidence for Delayed Age-related Hearing Loss in Two Long-lived Rodent Species (Peromyscus leucopus and P. californicus)

Deer mice (genus Peromyscus) are an emerging model for aging studies due to their longevity relative to rodents of similar size. Although Peromyscus species are well-represented in genetic, developmental, and behavioral studies, relatively few studies have investigated auditory sensitivity in this genus. Given the potential utility of Peromyscus for investigations of age-related changes to auditory function, we recorded auditory brainstem responses (ABRs) in two Peromyscus species, P. californicus, and P. leucopus, across the lifespan. We compared hearing sensitivity and ABR wave metrics measured in these species with measurements from Mus musculus (CBA/CaJ strain) to assess age-related effects on hearing across species. Recordings in young animals showed that all species had similar hearing ranges and thresholds with peak sensitivity ranging from 8 to 16 kHz; however, P. californicus and P. leucopus were more sensitive to frequencies below 8 kHz. Although M. musculus showed significant threshold shifts across a broad range of frequencies beginning at middle age and worsening among old individuals, older Peromyscus mice retained good sensitivity to sound across their lifespan. Middle-aged P. leucopus had comparable thresholds to young for frequencies below 24 kHz. P. leucopus also had notably large ABRs that were robust to age-related amplitude reductions, although response latencies increased with age. Old P. californicus were less sensitive to mid-range tones (8-16 kHz) than young individuals; however, there were no significant age-effects on ABR amplitudes or latencies in this species. These results indicate that longevity in Peromyscus mice may be correlated with delayed aging of the auditory system and highlight these species as promising candidates for longitudinal hearing research.

Evaluation of age-related changes in middle-ear structures by wideband tympanometry

BACKGROUND

Presbycusis is bilateral sensorineural hearing loss associated with the progressive degeneration of cochlear and central auditory pathways with aging.

AIMS/OBJECTIVES

We aimed to reveal age-related changes in middle ear function by using wideband tympanometry (WBT).

MATERIALS AND METHODS

Fifty-eight patients diagnosed with presbycusis were compared to 52 audiologically healthy participants. WBT measurement was performed on both ears via wideband click stimulus with a tympanometer device using probe tone frequencies of 226-8000 Hz.

RESULTS

There were no statistically significant differences detected among the resonance frequencies or maximum absorbance ratios measured in both ears between groups (p > .05). The mean absorbance of the right and left ears at 4000 and 8000 Hz was statistically higher in the patient group than in the healthy controls (r = 0.038, 0.030; l = 0.015, 0.012). Moreover, mean compliance values were found to be significantly lower in the patient group than in the control group (r = 0.030 and l = 0.040).

CONCLUSION

The significant differences detected in compliance and absorbance values for high frequencies in presbycusis patients were remarkable. Thus, it has been shown that WBT yields an advantage compared to traditional tympanometry in the diagnosis and treatment of middle ear diseases.

The Laterality of Age-related Hearing Loss and Cognition

Objectives

To analyze the association between neurocognitive performance and age-related hearing loss in the right and left ear, individually.

Design

Subjects included 5277 participants (≥50 years) from the general Hispanic population who underwent audiometric testing in a US multicentered epidemiologic study. Linear regression was performed to assess the cross-sectional association between cognitive performance (Digit Symbol Substitution Test [DSST], Word Frequency Test, Spanish-English Verbal Learning Test [SEVLT] 3 Trials, SEVLT Recall, and Six-Item Screener) and hearing in each ear (4-frequency pure-tone average), adjusting for age, sex, education, cardiovascular disease, and hearing aid use.

Results

Mean age was 58.4 ± 6.2 years; 3254 (61.7%) were women. Mean pure-tone averages were 20.2 ± 11.7 dB (right ear) and 20.2 ± 12.3 dB (left ear). Multivariable regression demonstrated significant associations between all cognitive tests and hearing loss in both ears.

Conclusions

Worsening hearing loss in the right and left ear was associated with decreased performance across all tests. No laterality in the association was demonstrated.

Validation of the French version of HHIE-S (Hearing Handicap Inventory for the Elderly - Screening) questionnaire in French over-60 year-olds

INTRODUCTION

The HHIE-S (Hearing Handicap Inventory for the Elderly - Screening) is widely used for hearing-loss disorder in the elderly. The main objective of the present study was to validate a French version. The secondary objective was to determinate a cut-off score as indication for hearing rehabilitation.

METHODS

We translated the HHIE-S into French, respecting the cross-cultural adaptation process for medical questionnaires. An observational study assessed the translation (10 questions, scored from 0 to 40) used for screening purposes in a prospective cohort, aged ≥60 years, with comparison to pure tone, speech-in-silence and speech-in-noise audiometry. Subjects were considered hearing-impaired if the pure-tone average at 500, 1,000, 2,000 and 4,000 Hz was >20 dB HL in one or both ears.

RESULTS

We tested 294 subjects (mean age =67±6 years). Hearing loss prevalence was 34.7 %. Cronbach's alpha (test reliability) was high (0.84). Taking HHIE-S score >8/40 as cut-off defining hearing loss, sensitivity was 80.4%, specificity 85.4 %, positive predictive value 74.5 % and negative predictive value 89.1 %. Seventy-three subjects (24.8 %) had theoretic indications for hearing aids, optimally detected by HHIE-S score >16/40 (88,4 %).

CONCLUSION

Our study validated the French version of the HHIE-S. This tool could be useful in screening for age-induced hearing loss in the elderly French population.

Age-related changes in event related potentials, steady state responses and temporal processing in the auditory cortex of mice with severe or mild hearing loss

Age-related changes in auditory processing affect the quality of life of older adults with and without hearing loss. To distinguish between the effects of sensorineural hearing loss and aging on cortical processing, the main goal of the present study was to compare cortical responses using the same stimulus paradigms and recording conditions in two strains of mice (C57BL/6J and FVB) that differ in the degree of age-related hearing loss. Electroencephalogram (EEG) recordings were obtained from freely moving young and old mice using epidural screw electrodes. We measured event related potentials (ERP) and 40 Hz auditory steady-state responses (ASSR). We used a novel stimulus, termed the gap-ASSR stimulus, which elicits an ASSR by rapidly presenting short gaps in continuous noise. By varying the gap widths and modulation depths, we probed the limits of temporal processing in young and old mice. Temporal fidelity of ASSR and gap-ASSR responses were measured as phase consistency across trials (inter-trial phase clustering; ITPC). The old C57 mice, which show severe hearing loss, produced larger ERP amplitudes compared to young mice. Despite robust ERPs, the old C57 mice showed significantly diminished ITPC in the ASSR and gap-ASSR responses, even with 100% modulation depth. The FVB mice, which show mild hearing loss with age, generated similar ERP amplitudes and ASSR ITPC across the age groups tested. However, the old FVB mice showed decreased gap-ASSR responses compared to young mice, particularly for modulation depths <100%. The C57 mice data suggest that severe presbycusis leads to increased gain in the auditory cortex, but with reduced temporal fidelity. The FVB mice data suggest that with mild hearing loss, age-related changes in temporal processing become apparent only when tested with more challenging sounds (shorter gaps and shallower modulation).

Identifying Subclinical Hearing Loss: Extended Audiometry and Word Recognition in Noise

INTRODUCTION

Normal-hearing people often have complaints about the ability to recognize speech in noise. Such disabilities are not typically assessed with conventional audiometry. Suprathreshold temporal deficits might contribute to reduced word recognition in noise as well as reduced temporally based binaural release of masking for speech. Extended high-frequency audibility (>8 kHz) has also been shown to contribute to speech perception in noise. The primary aim of this study was to compare conventional audiometric measures with measures that could reveal subclinical deficits.

METHODS

Conventional and extended high-frequency audiometry was done with 119 normal-hearing people ranging in age from 18 to 72. The ability to recognize words in noise was evaluated with and without differences in temporally based spatial cues. A low-uncertainty, closed-set word recognition task was used to limit cognitive influences.

RESULTS

In normal-hearing listeners, word recognition in noise ability decreases significantly with increasing pure-tone average (PTA). On average, signal-to-noise ratios worsened by 5.7 and 6.0 dB over the normal range, for the diotic and dichotic conditions, respectively. When controlling for age, a significant relationship remained in the diotic condition. Measurement error was estimated at 1.4 and 1.6 dB for the diotic and dichotic conditions, respectively. Controlling for both PTA and age, EHF-PTAs showed significant partial correlations with SNR50 in both conditions (ρ = 0.30 and 0.23). Temporally based binaural release of masking worsened with age by 1.94 dB from 18 to 72 years old but showed no significant relationship with either PTA.

CONCLUSIONS

All three assessments in this study demonstrated hearing problems independently of those observed in conventional audiometry. Considerable degradations in word recognition in noise abilities were observed as PTAs increased within the normal range. The use of an efficient words-in-noise measure might help identify functional hearing problems for individuals that are traditionally normal hearing. Extended audiometry provided additional predictive power for word recognition in noise independent of both the PTA and age. Temporally based binaural release of masking for word recognition decreased with age independent of PTAs within the normal range, indicating multiple mechanisms of age-related decline with potential clinical impact.

Can prestin level be a biomarker for determining sensorineural hearing loss?

OBJECTIVE

To determine prestin levels in patients with sensorineural hearing loss and to assess whether the prestin level could be a determining factor in predicting sensorineural hearing loss.

MATERIAL AND METHODS

The study was carried out with patients that presented to the Department of Otorhinolaryngology of Fırat University. Patients were divided into four groups of 30 subjects. Group 1: individuals aged ≥55 years with no hearing loss (control group); Group 2: individuals aged 20 to 55 years with no hearing loss (control group); Group 3: individuals aged 20 to 55 years with sensorineural hearing loss; Group 4: individuals aged ≥55 years with presbycusis. Following an audiometry examination, 5 cc blood was taken from all patients to assess serum prestin levels.

RESULTS

Prestin levels were 445.32 pg/mL in Group 1; 452.79 pg/mL in Group 2; 123.64 pg/mL in Group 3; and 79.54 pg/mL in Group 4. No difference was found between the serum prestin levels of the younger patients with hearing loss (Group 3)] and of the patients with presbycusis (Group 4) (p=0.084). No difference was found between the serum prestin levels of the younger (Group 1) and the older (Group 2) patients with presbycusis (p=0.399). Significant differences (with higher levels in the control groups) were found in between the prestin levels of between Group 3 (the younger patients with sensorineural hearing loss) and Group 2 (younger controls), and between Group 4 (older patients with presbycusis) and Group 1 (older controls) (p<0.001 and p <0.001, respectively).

CONCLUSION

Serum prestin levels can be used as biomarkers for assessing patients with presbycusis and sensorineural hearing loss. They can also be used together with audiometry tests to predict the patient's potential level of hearing loss.

Speech audiometry in noise: SNR Loss per age-group in normal hearing subjects

OBJECTIVES

The present study aimed to determine normal SNR values per age group for the 50% speech reception threshold in noise (SNR Loss) on the VRB (Vocale Rapide dans le Bruit: rapid speech in noise) test.

MATERIAL AND METHODS

Two hundred patients underwent pure-tone threshold and VRB speech-in-noise audiometry. Six ages groups were distinguished: 20-30, 30-40, 40-50, 50-60, 60-70 and>70 years. All subjects had normal hearing for age according to ISO 7029. SNR Loss was measured according to age group.

RESULTS

Mean SNR Loss ranged from -0.37dB in the youngest age group (20-30 years) to +6.84dB in the oldest (>70 years). Range and interquartile range increased with age: 3.66 and 1.49dB respectively for 20-30 year-olds; 6 and 3.5dB for>70 year-olds. Linear regression between SNR Loss and age showed a coefficient R² of 0.83.

CONCLUSION

The present study reports SNR Loss values per age group in normal-hearing subjects (ISO 7029), confirming that SNR Loss increases with age. Scatter also increased with age, suggesting that other age-related factors combine with inner-ear aging to impair hearing in noise.

A novel dynamic network imaging analysis method reveals aging-related fragmentation of cortical networks in mouse

Network analysis of large-scale neuroimaging data is a particularly challenging computational problem. Here, we adapt a novel analytical tool, the community dynamic inference method (CommDy), for brain imaging data from young and aged mice. CommDy, which was inspired by social network theory, has been successfully used in other domains in biology; this report represents its first use in neuroscience. We used CommDy to investigate aging-related changes in network metrics in the auditory and motor cortices by using flavoprotein autofluorescence imaging in brain slices and in vivo. We observed that auditory cortical networks in slices taken from aged brains were highly fragmented compared to networks observed in young animals. CommDy network metrics were then used to build a random-forests classifier based on NMDA receptor blockade data, which successfully reproduced the aging findings, suggesting that the excitatory cortical connections may be altered during aging. A similar aging-related decline in network connectivity was also observed in spontaneous activity in the awake motor cortex, suggesting that the findings in the auditory cortex reflect general mechanisms during aging. These data suggest that CommDy provides a new dynamic network analytical tool to study the brain and that aging is associated with fragmentation of intracortical networks.

Evaluation of the vestibular system in individuals with presbycusis using video head impulse test and videonystagmography

BACKGROUND

Vestibulo-ocular reflex (VOR) function is expected to be normal in patients with presbycusis during sudden head rotations.

AIM

This study aimed to determine whether presbycusis was accompanied by vestibular system pathologies. In addition, it was examined whether there was a difference existed between the patients with and without presbycusis in terms of normative data.

MATERIALS AND METHODS

A total of 40 individuals were included in the study: 20 in the presbycusis group and 20 in the control group. The vestibular systems of both groups were evaluated using the video head impulse test and videonystagmography.

RESULTS

The right and left lateral VOR gain values were decreased in the group with presbycusis compared to the control group. The difference between the two groups in the mean VOR gains in the right lateral canal and left lateral canal were statistically significant (p = .040 and p = .050, respectively). The air caloric tests of all individuals were found to be normal.

CONCLUSIONS

This result suggests that the loss of vestibular hair cells and vestibular nerve degeneration in the lateral semicircular canal may be more severe in presbycusis than in the same age group with normal hearing.

Subjective vision and hearing impairment and falls among community-dwelling adults: a prospective study in the Survey of Health, Ageing and Retirement in Europe (SHARE)

PURPOSE

To investigate the association between vision and hearing impairment and falls in community-dwelling adults aged ≥ 50 years.

METHODS

This is a prospective study on 50,986 participants assessed in Waves 6 and 7 of the Survey of Health, Ageing and Retirement in Europe. At baseline, we recorded socio-demographic data, clinical factors and self-reported vision and hearing impairment. We classified participants as having good vision and hearing, impaired vision, impaired hearing or impaired vision and hearing. We recorded falls in the six months prior to the baseline and 2-year follow-up interviews. The cross-sectional and longitudinal associations between vision and hearing impairment categories and falls were analysed by binary logistic regression models; odds ratios (OR) and 95% confidence intervals (CI) were calculated. All analyses were adjusted for socio-demographic and clinical factors.

RESULTS

Mean age was 67.1 years (range 50-102). At baseline, participants with impaired vision, impaired hearing, and impaired vision and hearing had an increased falls risk (OR (95% CI)) of 1.34 (1.22-1.49), 1.34 (1.20-1.50) and 1.67 (1.50-1.87), respectively, compared to those with good vision and hearing (all p < 0.001). At follow-up, participants with impaired vision, without or with impaired hearing, had an increased falls risk of 1.19 (1.08-1.31) and 1.33 (1.20-1.49), respectively, compared to those with good vision and hearing (both p < 0.001); hearing impairment was longitudinally associated with falls in middle-aged women.

CONCLUSION

Vision impairment was cross-sectionally and longitudinally associated with an increased falls risk. This risk was highest in adults with dual sensory impairment.

Does Auditory Environment Predict Speech Perception Outcomes in Elderly Cochlear Implant Patients?

INTRODUCTION

Cochlear implantation (CI) is a reliable and safe means by which sensorineural hearing loss can be ameliorated in the elderly population. However, a high degree of variation exists in postimplantation hearing outcomes for which some modifiable factors of the daily natural auditory environment may be contributory. In this study, we analyze the relationship between cochlear implant patient age, natural auditory environment, and postimplantation speech perception among older adults.

METHODS

Data log from automatic environment classification enabled sound processors of postlingually deafened CI recipients ≥50 years old (n = 115) were obtained retrospectively and analyzed for time spent (hours per day) in listening environment and loudness (SPL dB). Speech perception testing was assessed in a subset of patients (n = 27) using open-set word recognition in quiet Consonant-Nucleus-Consonant in the short and intermediate postoperative period.

RESULTS

The mean subject age was 70 years (range, 53-99 years). Average daily implant use was 10.8 h and was not significantly correlated with age (p = 0.23, Spearman's rho). Age was positively correlated with the percentage of hours spent at <40 and 40-50 dB and negatively correlated to proportional CI use at higher volume (60-70, 70-80, and >80 dB; rs = 0.21, 0.20, -0.20, -0.35, -0.43; p = 0.021, 0.036, 0.033, <0.001, <0.001, respectively). Age was positively correlated with CI use in the quiet scene (rs = 0.26, p = 0.006) and negatively correlated with scenes containing speech and noise (rs = -0.19, -0.25; p = 0.046, 0.007). Total hours of device use and time spent at <40, 40-50 dB, and quiet environments were significantly correlated with improved CNC word scores (rs = 0.48, 0.48, 0.51; p = 0.01, 0.01, <0.01, Spearman's rho). While all speech (speech in noise + speech) was not significantly correlated to improvements in speech perception, a medium effect size was observed (rs = 0.37, p = 0.057).

DISCUSSION/CONCLUSION

This study supports a relationship between auditory environment and age, with older CI recipients spending a greater proportion of time in quiet. Older CI users demonstrated greater improvements in speech perception with longer daily device use. Additional examination of the relationship between auditory environment and speech perception is necessary to conclusively guide future auditory rehabilitation efforts.

Aberrant brain functional hubs and causal connectivity in presbycusis

To investigate resting-state connectivity and further understand directional aspects of implicit alterations in presbycusis patients, we used degree centrality (DC) and Granger causality analysis (GCA) to detect functional hubs of the whole-brain network and then analyze directional connectivity. Resting-state functional magnetic resonance imaging (fMRI) scans were performed on 40 presbycusis patients and 40 healthy controls matched for age, gender, and education. We used DC analysis and GCA to characterize abnormal brain networks in presbycusis patients. The associations of network centrality and directed functional connectivity (FC) with clinical measures of presbycusis were also examined according to the above results. We found that the network centrality of left frontal middle gyrus (MFG) was significantly lower than that of healthy control group. Unidirectionally, the left MFG revealed increased directional connectivity to the left superior frontal gyrus (SFG), while the left MFG exhibited decreased directional connectivity to the left middle temporal gyrus (MTG) and right lingual gyrus (LinG). And the decreased directional connectivity was found from the left precentral gyrus (PrCG) to the left MFG. In addition, the Trail-Making Test B (TMT-B) score was negatively correlated with the decreased DC of the left MFG (r = -0.359, p = 0.032). Resting-state fMRI provides a novel method for identifying aberrant brain network architecture. These results primarily indicate altered functional hubs and abnormal frontal lobe connectivity patterns that may further reflect executive dysfunction in patients with presbycusis.

Directed functional connectivity of the hippocampus in patients with presbycusis

Presbycusis, associated with a diminished quality of life characterized by bilateral sensorineural hearing loss at high frequencies, has become an increasingly critical public health problem. This study aimed to identify directed functional connectivity (FC) of the hippocampus in patients with presbycusis and to explore the causes if the directed functional connections of the hippocampus were disrupted. Presbycusis patients (n = 32) and age-, sex-, and education-matched healthy controls (n = 40) were included in this study. The seed regions of bilateral hippocampus were selected to identify directed FC in patients with presbycusis using Granger causality analysis (GCA) approach. Correlation analyses were conducted to detect the associations of disrupted directed FC of hippocampus with clinical measures of presbycusis. Compared to healthy controls, decreased directed FC between inferior parietal lobule, insula, right supplementary motor area, middle temporal gyrus and hippocampus were detected in presbycusis patients. Furthermore, a negative correlation between TMB score and the decline of directed FC from left inferior parietal lobule to left hippocampus (r = -0.423, p = 0.025) and from right inferior parietal lobule to right hippocampus (r = -0.516, p = 0.005) were also observed. The decreased directed functional connections of the hippocampus were detected in patients with presbycusis, which was associated with specific cognitive performance. This study mainly emphasizes the crucial role of hippocampus in presbycusis and will enhance our understanding of the neuropathological mechanisms of presbycusis.

Bilateral age-related atrophy in the planum temporale is associated with vowel discrimination difficulty in healthy older adults

In this study we investigated the association between age-related brain atrophy and behavioural as well as electrophysiological markers of vowel perception in a sample of healthy younger and older adults with normal pure-tone hearing. Twenty-three older adults and 27 younger controls discriminated a set of vowels with altered second formants embedded in consonant-vowel syllables. Additionally, mismatch negativity (MMN) responses were recorded in a separate oddball paradigm with the same set of stimuli. A structural magnet resonance scan was obtained for each participant to determine cortical architecture of the left and right planum temporale (PT). The PT was chosen for its function as a major processor of auditory cues and speech. Results suggested that older adults performed worse in vowel discrimination despite normal-for-age pure-tone hearing. In the older group, we found evidence that those with greater age-related cortical atrophy (i.e., lower cortical surface area and cortical volume) in the left and right PT also showed weaker vowel discrimination. In comparison, we found a lateralized correlation in the younger group suggesting that those with greater cortical thickness in only the left PT performed weaker in the vowel discrimination task. We did not find any associations between macroanatomical traits of the PT and MMN responses. We conclude that deficient vowel processing is not only caused by pure-tone hearing loss but is also influenced by atrophy-related changes in the ageing auditory-related cortices. Furthermore, our results suggest that auditory processing might become more bilateral across the lifespan.

Stem Cells and Gene Therapy in Progressive Hearing Loss: the State of the Art

Progressive non-syndromic sensorineural hearing loss (PNSHL) is the most common cause of sensory impairment, affecting more than a third of individuals over the age of 65. PNSHL includes noise-induced hearing loss (NIHL) and inherited forms of deafness, among which is delayed-onset autosomal dominant hearing loss (AD PNSHL). PNSHL is a prime candidate for genetic therapies due to the fact that PNSHL has been studied extensively, and there is a potentially wide window between identification of the disorder and the onset of hearing loss. Several gene therapy strategies exist that show potential for targeting PNSHL, including viral and non-viral approaches, and gene editing versus gene-modulating approaches. To fully explore the potential of these therapy strategies, a faithful in vitro model of the human inner ear is needed. Such models may come from induced pluripotent stem cells (iPSCs). The development of new treatment modalities by combining iPSC modeling with novel and innovative gene therapy approaches will pave the way for future applications leading to improved quality of life for many affected individuals and their families.

Patterns of hearing changes in women and men from denarians to nonagenarians

Background

Hearing loss needs to be diagnosed and treated early, especially in older individuals, since presbycusis potentially increases the risk of depression and dementia. However, standard data on hearing thresholds across the life-span in Japanese individuals are lacking.

Methods

In a retrospective consecutive sample of 10681 native-Japanese speakers (37.3% men; 10-99 years; left-right hearing threshold difference of <15 dB for all tested pure tones; free of external, middle, or inner ear disease), we determined standard age-decade and sex-specific pure-tone air-conduction (125, 250, 500, 1000, 2000, 4000, and 8000 Hz) hearing threshold norms. The main outcome measures were pure-tone averages for both ears by age-decade and sex.

Findings

For participants in their 20s, hearing thresholds at higher frequencies (>1000 Hz) were significantly worse in men than in women. For participants ≥70 years, hearing thresholds at low frequencies were higher in women. Hearing thresholds at 1000, 2000, and 4000 Hz tended to deteriorate, starting in the teenage years through the 50s, with some decades showing significantly worse decline. Sex differences were absent in the youngest and oldest groups.

Interpretation

Standard age- and sex-specific audiometric data reported here for Japanese individuals over nine age-decades are based on the largest dataset analyzed to date. While hearing thresholds of men and women in the very young and the very old age groups were indistinguishable in their cohorts, patterns of hearing changes for other age cohorts differed by direction and sex.

Funding

The authors had no outside funding for this study.

Totally implantable active middle-ear implants: a large, single-surgeon cohort

OBJECTIVES

This study aimed to evaluate hearing outcomes and device safety in a large, single-surgeon experience with the totally implantable active middle-ear implants.

METHODS

This was a retrospective case series review of 116 patients with moderate-to-severe sensorineural hearing loss undergoing implantation of active middle-ear implants.

RESULTS

Mean baseline unaided pure tone average improved from 57.6 dB before surgery to 34.1 dB post-operatively, signifying a mean gain in pure tone average of 23.5 dB (p = 0.0002). Phonetically balanced maximum word recognition score improved slightly from 70.5 per cent to 75.8 per cent (p = 0.416), and word recognition score at a hearing level of 50 dB values increased substantially from 14.4 per cent to 70.4 per cent (p < 0.0001). Both revision and explant rates were low and dropped with increasing surgeon experience over time.

CONCLUSION

This study showed excellent post-operative hearing results with active middle-ear implants with regard to pure tone average and word recognition score at a hearing level of 50 db. Complication rates in this case series were significantly lower with increasing experience of the surgeon. Active middle-ear implants should be considered in appropriate patients with moderate-to-severe sensorineural hearing loss who have struggled with conventional amplification and are good surgical candidates.

Association between Speech Recognition in Noise and Risk Factors of Cardiovascular Disease

INTRODUCTION

Risk factors for cardiovascular disease (CVD) are associated with sensorineural hearing loss. CVD risk factors are known to cluster and interact, thereby increasing the cumulative risk for CVD. Previously, using the database of the Netherlands Longitudinal Study on Hearing (NL-SH), an association was found between a history of smoking and an increased decline in speech recognition in noise over 10 years of follow-up. Prospectively limited data are available on the association between CVD risk factors, interactions of these risk factors, and hearing loss. In this study, data from the NL-SH were used to study the association between CVD risk factors and speech recognition in noise longitudinally.

METHODS

Baseline, 5-year, and 10-year follow-up data of the NL-SH were included. The NL-SH is a web-based prospective cohort study which started in 2006. Participants were aged 18-70 years at baseline. Speech recognition in noise was determined with an online digit-triplet speech-in-noise test. In addition, participants completed online questionnaires on demographic, lifestyle, and health-related characteristics. The association of the ability to recognize speech in noise with CVD risk factors (i.e., obesity, rheumatoid arthritis [RA], hypertension, diabetes mellitus, and dyslipidemia) was analyzed longitudinally. We also analyzed the interaction between these risk factors (including age, sex, and history of smoking) and speech recognition in noise.

RESULTS

None of the CVD risk factors or interactions of 2 CVD risk factors was significantly associated with a decline in SRT over time. Obesity (p = 0.016), RA (p = 0.027), and hypertension (p = 0.044) were associated with overall higher (more unfavorable) SRTs. No overall interactions between CVD risk factors were found.

CONCLUSION

Obesity, RA, and hypertension were overall associated with a higher SRT, but no longitudinal associations between these or other CVD factors with SRTs were found. Also, no interactions between 2 CVD risk factors and SRTs were found. Although no longitudinal associations between CVD risk factors and decline in SRTs were found, clinicians should be alert about the concurrent association between CVD risk factors and hearing loss.

Age-related loss of auditory sensitivity in the zebrafish (Danio rerio)

Age-related hearing loss (ARHL), also known as presbycusis, is a widespread and debilitating condition impacting many older adults. Conventionally, researchers utilize mammalian model systems or human cadaveric tissue to study ARHL pathology. Recently, the zebrafish has become an effective and tractable model system for a wide variety of genetic and environmental auditory insults, but little is known about the incidence or extent of ARHL in zebrafish and other non-mammalian models. Here, we evaluated whether zebrafish exhibit age-related loss in auditory sensitivity. The auditory sensitivity of adult wild-type zebrafish (AB/WIK strain) from three adult age subgroups (13-month, 20-month, and 37-month) was characterized using the auditory evoked potential (AEP) recording technique. AEPs were elicited using pure tone stimuli (115-4500 Hz) presented via an underwater loudspeaker and recorded using shielded subdermal metal electrodes. Based on measures of sound pressure and particle acceleration, the mean AEP thresholds of 37-month-old fish [mean sound pressure level (SPL) = 122.2 dB ± 2.2 dB SE re: 1 μPa; mean particle acceleration level (PAL) = -27.5 ± 2.3 dB SE re: 1 ms^-2] were approximately 9 dB higher than that of 20-month-old fish [(mean SPL = 113.1 ± 2.7 dB SE re: 1 μPa; mean PAL = -37.2 ± 2.8 dB re: 1 ms^-2; p = 0.007)] and 6 dB higher than that of 13-month-old fish [(mean SPL = 116.3 ± 2.5 dB SE re: 1 μPa; mean PAL = -34.1 ± 2.6 dB SE re: 1 ms^-2; p = 0.052)]. Lowest AEP thresholds for all three age groups were generally between 800 Hz and 1850 Hz, with no evidence for frequency-specific age-related loss. Our results suggest that zebrafish undergo age-related loss in auditory sensitivity, but the form and magnitude of loss is markedly different than in mammals, including humans. Future work is needed to further describe the incidence and extent of ARHL across vertebrate groups and to determine which, if any, ARHL mechanisms may be conserved across vertebrates to support meaningful comparative/translational studies.

Age-related hearing loss pertaining to potassium ion channels in the cochlea and auditory pathway

Age-related hearing loss (ARHL) is the most prevalent sensory deficit in the elderly and constitutes the third highest risk factor for dementia. Lifetime noise exposure, genetic predispositions for degeneration, and metabolic stress are assumed to be the major causes of ARHL. Both noise-induced and hereditary progressive hearing have been linked to decreased cell surface expression and impaired conductance of the potassium ion channel K_V7.4 (KCNQ4) in outer hair cells, inspiring future therapies to maintain or prevent the decline of potassium ion channel surface expression to reduce ARHL. In concert with K_V7.4 in outer hair cells, K_V7.1 (KCNQ1) in the stria vascularis, calcium-activated potassium channels BK (KCNMA1) and SK2 (KCNN2) in hair cells and efferent fiber synapses, and K_V3.1 (KCNC1) in the spiral ganglia and ascending auditory circuits share an upregulated expression or subcellular targeting during final differentiation at hearing onset. They also share a distinctive fragility for noise exposure and age-dependent shortfalls in energy supply required for sustained surface expression. Here, we review and discuss the possible contribution of select potassium ion channels in the cochlea and auditory pathway to ARHL. We postulate genes, proteins, or modulators that contribute to sustained ion currents or proper surface expressions of potassium channels under challenging conditions as key for future therapies of ARHL.

CYP1A1 and GSTs common gene variations and presbycusis risk: a genetic association analysis and a bioinformatics approach

Antioxidant enzymes such as glutathione S-transferases (GSTs) and cytochromes P450 (CYPs) are involved in the metabolism and detoxification of cytotoxic compounds, as well as the elimination of reactive oxygen species (ROS). Therefore, alterations in the structure of these enzymes could result in prolonged production of ROS with subsequent risk of development of disorders such as presbycusis. This study aimed to investigate the association between CYP1A1 (rs4646903, rs1048943) and GSTs (GSTM1-deletion, GSTT1-deletion, GSTP1-rs1695) with presbycusis risk in an Iranian population which was followed by an in silico approach. In a case-control study, 280 subjects including 140 cases with presbycusis and 140 healthy controls were enrolled. Genotypes of single-nucleotide polymorphisms (SNPs) were detected by PCR-RFLP method and the genotype of the above mentioned deletions was determined by touchdown PCR. Some bioinformatics tools were employed to evaluate the impact of SNPs on the gene function. SNP analysis revealed that there are significant associations between rs1048943 (AG vs. AA: OR = 2.46, 95%CI = 1.30-4.65, p = 0.006; GG + AG vs. AA: OR = 2.53, 95%CI = 1.36-4.69, p = 0.003; G vs. A: OR = 2.36, 95%CI = 1.33-4.17, p = 0.003) and rs4646903 (C vs. T: OR = 1.45, 95%CI = 1.02-2.06, p = 0.040) variations and increased risk of presbycusis. However, there was no significant association between rs1695 and presbycusis risk. Also, significant associations were observed between GSTM1 (OR = 4.28, 95%CI = 1.18-15.52, p = 0.027) and GSTT1 (OR = 1.64, 95%CI = 1.02-2.65, p = 0.041) deletions and elevated risk of presbycusis. Moreover, the combination analysis revealed a significant association between GSTM1+/GSTT1- genotype and presbycusis susceptibility (OR = 1.63, 95%CI = 1.00-2.67, p = 0.049). In silico analysis revealed that the rs1048943 SNP could influence significantly on the RNA structure of CYP1A1 (distance: 0.1454; p value: 0.1799). Based on our findings, the rs4646903, rs1048943 SNPs as well as GSTM1 and GSTT1 deletions could be considered as genetic risk factors for the development and progression of presbycusis.

Effects of age on psychophysical measures of auditory temporal processing and speech reception at low and high levels

•

We found little evidence of greater age-related hearing declines at high sound levels.

•

There are age-related temporal-processing declines independent of hearing loss.

•

No evidence of age-related speech-reception deficits independent of hearing loss.

Age-related cochlear synaptopathy (CS) has been shown to occur in rodents with minimal noise exposure, and has been hypothesized to play a crucial role in age-related hearing declines in humans. It is not known to what extent age-related CS occurs in humans, and how it affects the coding of supra-threshold sounds and speech in noise. Because in rodents CS affects mainly low- and medium-spontaneous rate (L/M-SR) auditory-nerve fibers with rate-level functions covering medium-high levels, it should lead to greater deficits in the processing of sounds at high than at low stimulus levels. In this cross-sectional study the performance of 102 listeners across the age range (34 young, 34 middle-aged, 34 older) was assessed in a set of psychophysical temporal processing and speech reception in noise tests at both low, and high stimulus levels. Mixed-effect multiple regression models were used to estimate the effects of age while partialing out effects of audiometric thresholds, lifetime noise exposure, cognitive abilities (assessed with additional tests), and musical experience. Age was independently associated with performance deficits on several tests. However, only for one out of 13 tests were age effects credibly larger at the high compared to the low stimulus level. Overall these results do not provide much evidence that age-related CS, to the extent to which it may occur in humans according to the rodent model of greater L/M-SR synaptic loss, has substantial effects on psychophysical measures of auditory temporal processing or on speech reception in noise.

Emotional prosody perception in presbycusis patients after auditory rehabilitation

OBJECTIVE

Perception of emotion plays a major role in social interaction. Studies have shown that hearing loss and aging degrade emotional recognition. The main aim of the present study was to evaluate the benefit of first-time hearing aids (HA) for emotional prosody perception in presbycusis patients. Secondary objectives comprised comparison with normal-hearing subjects, and assessment of the impact of demographic and audiologic factors.

METHODS

To assess HA impact, 29 subjects with presbycusis were included. They were tested without HA and 1 month after starting to use HA. A test with emotional hearing stimuli (Montreal Affective Voice test: MAV) was performed at various intensities (50, 65 and 80dB SPL). Patients' experience was evaluated on the Profile of Emotional Competence questionnaire, before and after HA fitting. Results were compared with those of 29 normal-hearing subjects.

RESULTS

Auditory rehabilitation did not significantly improve MAV results (P>0.005), or subjective questionnaire results (P>0.005). Scores remained lower than those of normal-hearing subjects (P<0.001). MAV results, before and after HA, showed significant correlation with pure-tone average (r=-0.88, P<0.001) and age (r=0.44, P=0.018). The older the presbycusis patient and the more severe the hearing loss, the greater the difficulty in recognising emotional prosody.

CONCLUSION

Despite hearing rehabilitation, presbycusis patients' results remained poorer than in normal-hearing subjects.

Prevention and Rehabilitation of Old Age Deafness

Hearing impairment is one of the most common sensory deficit affecting 466 million people globally and in majority of old age people it can not corrected. Since presbycusis is always associated with diminished cognition power resulting in two fold loss in understanding of speech. There is no treatment available till date to regenerate the hair cells but certainly we can augment hearing by preventing and regenerating (apoptosis) atrophy of stria vascularis, spiral neural cells degeneration, atrophy of auditory nerve and cerebral cortex by modified greeva, skandh chalan, dynamic neurobics, tratak (focused concentration), Bhramari, Kumbhak along with mindful relaxation technique.

Frequency-lowering processing to improve speech-in-noise intelligibility in patients with age-related hearing loss

OBJECTIVE

Modern hearing aids use various signal-processing strategies to improve speech intelligibility. In this manuscript, we studied the linear frequency transposition (LFT), a frequency-lowering algorithm, in patients with age-related hearing loss. Frequency-lowering algorithms transpose high-frequency sounds to a lower-frequency band. The study aimed to assess whether LFT could be used as a tool to improve speech intelligibility in patients with a better high-frequency preservation.

METHODS

The study population consisted of 77 patients (age average 74.8 ± 12.4) wearing hearing aids with an open or tulip coupling system with age-related hearing loss. The unaided air conduction pure tone average (PTA) at 500, 1000, 2000 Hz was 43.5 ± 14.3 dB; the unaided word recognition score (WRS) average was 53.7 ± 12.5%. We compared WRS in all patients with the hearing aid turned on, in "quiet" and using a "pink" and "babble" masking noise. Three hearing aid settings were tested in each acoustic conditions: no transposition (NT), high transposition (HT), and low transposition (LT). "High" and "low" refer to the "start frequency"; all sounds above the start frequency are transposed in a lower-frequency band. When the start frequency was suggested by the fitting software, we called the condition "high transposition"; when the start frequency was set at the lowest possible value provided by the fitting software, we called the condition "low transposition". The quality of the voice was also assessed asking the patient to give a score from 1 to 10, where 10 was the maximum listening comfort [quality of voice score (QVS)].

RESULTS

Collected data were compared for each condition (NT, HT, LT, in quiet, pink noise and babble noise) and no statistically significant differences were found in WRS and QVS (quiet WRS p = 0.07, pink noise WRS p = 0.18, babble noise WRS p = 0.11, QVS p = 0.91). We selected 33 patients with a better WRS in babble noise using transposition (high and low). In this group, the age was significantly lower than patients who did not use transposition (p = 0.01).

CONCLUSION

Linear frequency transposition is not useful to improve speech-in-noise intelligibility in patients with age-related hearing loss. Despite that no statistically significant differences were found, younger people could get advantages from the LFT when babble noise disturbs the listening of speech. The use of FL algorithm as a way to improve speech intelligibility in noisy environments should be always considered.

Telemedicine in Audiology. Best practice recommendations from the French Society of Audiology (SFA) and the French Society of Otorhinolaryngology-Head and Neck Surgery (SFORL)

Objectives

Access to diagnosis and treatments for auditory disorders and related pathologies has regressed in France during the COVID-19 pandemic, posing a risk to the patient's chance of recovery. This best practice recommendations guide aims to list the existing technological solutions for the remote examination of a patient with hearing complaint, and to outline their benefits and, where applicable, their limitations.

Methods

The recommendations were developed both from the clinical experience of the medical experts who drafted the guide, and from an extensive review of the literature dealing with clinical practice recommendations for tele-audiology. Tele-audiometry solutions were identified on the basis of a search engine query carried out in April 2020, prior to verification of their availability on the European market.

Results

Video otoscopy solutions allow for the teletransmission of images compatible with a high-quality diagnosis, either by connecting via internet to a tele-health platform or using a smartphone or a tablet with an iOS or Android operating system. Using the same telecommunication methods, it is possible to remotely conduct a pure-tone audiometry test in accordance with standard practice, a speech-in-quiet or a speech-in-noise audiometry test, as well as objective measures of hearing. Clinical and paraclinical examinations can be accessed by the physician to be interpreted on a deferred basis (asynchronous tele-audiology). Examinations can also be conducted in real time in a patient, at any age of life, as long as a caregiver can be present during the installation of the transducers or the acoumetry. Tele-audiology solutions also find application in the remote training of future healthcare professionals involved in the management of deafness and hearing impairment.

Conclusion

Under French law, tele-otoscopy is a medical procedure that is either a tele-expertise (asynchronous adive) or a teleconsultation act (synchronous advice). Subjective and objective evaluation of the patient's hearing functions can be done remotely provided that the listed precautions are respected.

[Hearing loss and social frailty in older men and women]

OBJECTIVE

To explore the association between hearing loss and social frailty in a sample of Spanish older adults recruited from primary health care network.

METHOD

Cross-sectional study on a sample of 445 non-institutionalized adults aged 65 or more years (190 men and 255 women), recruited from primary care centers in Spain. Three self-reported hearing impairment questions were used to assess hearing loss. Social frailty was deemed to exist when the person presented two or more of the following conditions: living alone, absence of a person to provide help, infrequent contact with family, infrequent contact with friends, lack of confident and lack of help for daily activities in the last 3 months. To study the association between hearing loss and social frailty we used logistic regression models adjusted for potential confounders, including physical frailty.

RESULTS

The mean age of participants was 76.2 years (77.5 years for women). More than half of the participants (54.4%) reported hearing loss and the frequency of social frailty was 23.2%. Hearing loss was associated with social frailty (adjusted odds ratio [aOR]=1.78; 95% confidence interval [95%CI]: 1.04-3.06). However, the association was sex-dependent (p for interaction=0.041). In stratified analysis, the association was only found in women (aOR=3.21; 95%CI: 1.44-7.17).

CONCLUSIONS

Hearing loss was associated with social frailty in women, but not in men. Longitudinal studies are needed to confirm this association and to understand the differential effect of gender.

Hearing and speech processing in midlife

Middle-aged adults often report a decline in their ability to understand speech in adverse listening situations. However, there has been relatively little research devoted to identifying how early aging affects speech processing, as the majority of investigations into senescent changes in speech understanding compare performance in groups of young and older adults. This paper provides an overview of research on hearing and speech perception in middle-aged adults. Topics covered include both objective and subjective (self-perceived) hearing and speech understanding, listening effort, and audiovisual speech perception. This review ends with justification for future research needed to define the nature, consequences, and remediation of hearing problems in middle-aged adults.

Age- and movement-related modulation of cortical oscillations in a mouse model of presbycusis

Brain oscillations are associated with specific cognitive and sensory processes. How age-related hearing loss (presbycusis) alters cortical oscillations is unclear. Altered inhibitory neurotransmission and temporal processing deficits contribute to speech recognition impairments in presbycusis. Specifically, age-related reduction in parvalbumin positive interneurons and perineuronal nets in the auditory cortex predicts a reduction in gamma oscillations that may lead to a decline in temporal precision and attention. To test the hypothesis that resting and evoked gamma oscillations decline with presbycusis, EEGs were recorded from the auditory and frontal cortex of awake, freely moving C57BL/6 J mice at three ages (3, 14 and 24 months). Resting EEG data were analyzed according to movement state (move versus still). Evoked responses were recorded following presentation of noise bursts or amplitude modulated noise with time varying modulation frequencies. We report an age-related decrease in resting gamma power, a decline in gamma-range synchrony to time varying stimuli, and an increase in noise evoked and induced gamma power. A decline in temporal processing is seen in aged mice that exhibit robust auditory-evoked potentials, dissociating hearing loss from temporal processing deficits. We also report an increase in gamma power when mice moved compared to the still state. However, the movement-related modulation of gamma oscillations did not change with age. Together, these data identify a number of novel markers of presbycusis-related changes in auditory and frontal cortex. Because EEGs are commonly recorded in humans, the mouse data may serve as translation relevant preclinical biomarkers to facilitate the development of therapeutics to delay or reverse central auditory processing deficits in presbycusis.

Translational implications of the interactions between hormones and age-related hearing loss

Provocative research has revealed both positive and negative effects of hormones on hearing as we age; with in some cases, mis-regulation of hormonal levels in instances of medical comorbidities linked to aging, lying at the heart of the problem. Animal model studies have discovered that hormonal fluctuations can sharpen hearing for improved communication and processing of mating calls during reproductive seasons. Sex hormones sometimes have positive effects on auditory processing, as is often the case with estrogen, whereas combinations of estrogen and progesterone, and testosterone, can have negative effects on hearing abilities, particularly in aging subjects. Too much or too little of some hormones can be detrimental, as is the case for aldosterone and thyroid hormones, which generally decline in older individuals. Too little insulin, as in Type 1 diabetics, or poor regulation of insulin, as in Type 2 diabetics, is also harmful to hearing in our aged population. In terms of clinical translational possibilities, hormone therapies can be problematic due to systemic side effects, as has happened for estrogen/progestin combination hormone replacement therapy (HRT) in older women, where the HRT induces a hearing loss. As hormone therapy approaches are further developed, it may be possible to lower needed doses of hormones by combining them with supplements, such as antioxidants. Another option will be to take advantage of emerging technologies for local drug delivery to the inner ear, including biodegradeable, sustained-release hydrogels and micro-pumps which can be implanted in the middle ear near the round window. In closing, exciting research completed to date, summarized in the present report bodes well for emerging biomedical therapies to prevent or treat age-related hearing loss utilizing hormonal strategies.

Coprevalence of Presbycusis and Its Effect on Outcome of Voice Therapy in Patients With Presbyphonia

OBJECTIVE

To identify the coprevalence of presbycusis and presbycusis and analyze the effect of presbycusis on compliance and result of voice therapy in presbycusis patients.

METHODS

This cross-sectional, prospective cohort study initially screened patients aged ≥65 years who visited our hospital from February 2019 to January 2020. Unaided pure tone audiometry was performed in these subjects to determine the presence of presbycusis. Perceptual voice assessment by an examiner was conducted for screening of presbycusis, and its diagnosis was confirmed through the voice handicap index-10 (VHI-10) questionnaire and a laryngoscopic exam. Patients with presbycusis underwent voice therapy and were assessed for their compliance and outcomes of the treatment according to the coexistence of presbycusis.

RESULTS

Among the 221 patients, presbycusis and presbycusis were diagnosed in 125 (56.6%) and 110 (49.8%) patients, respectively. The copresence of these two disorders were identified in 87 (39.4%) patients, and there was a significant correlation between presbycusis and presbycusis. The effects of voice therapy were examined in the consecutive 40 patients who were diagnosed with presbycusis. There were 21 patients without presbycusis and 19 patients with presbycusis. The average pretreatment voice handicap index-10 score was significantly higher in presbycusis patients; there was no significant difference in the incidence of dropout from voice therapy between the groups. The patients without presbycusis showed a significant improvement in the functional communication measurement (FCM) level and maximum phonation time (MPT) compared with those of patients with presbycusis after voice therapy.

CONCLUSIONS

Presbyphonia and presbycusis coexisted in many elderly people. The improvement in the FCM level and MPT after voice therapy was relatively low if patients with presbycusis accompanied by presbycusis. The copresence of presbycusis did not significantly affect compliance with voice therapy in the patients.

Effects of age on electrophysiological measures of cochlear synaptopathy in humans

Age-related cochlear synaptopathy (CS) has been shown to occur in rodents with minimal noise exposure, and has been hypothesized to play a crucial role in age-related hearing declines in humans. Because CS affects mainly low-spontaneous rate auditory nerve fibers, differential electrophysiological measures such as the ratio of the amplitude of wave I of the auditory brainstem response (ABR) at high to low click levels (WIH/WIL), and the difference between frequency following response (FFR) levels to shallow and deep amplitude modulated tones (FFRS-FFRD), have been proposed as CS markers. However, age-related audiometric threshold shifts, particularly prominent at high frequencies, may confound the interpretation of these measures in cross-sectional studies of age-related CS. To address this issue, we measured WIH/WIL and FFRS-FFRD using highpass masking (HP) noise to eliminate the contribution of high-frequency cochlear regions to the responses in a cross-sectional sample of 102 subjects (34 young, 34 middle-aged, 34 older). WIH/WIL in the presence of the HP noise did not decrease as a function of age. However, in the absence of HP noise, WIH/WIL showed credible age-related decreases even after partialing out the effects of audiometric threshold shifts. No credible age-related decreases of FFRS-FFRD were found. Overall, the results do not provide evidence of age-related CS in the low-frequency region where the responses were restricted by the HP noise, but are consistent with the presence of age-related CS in higher frequency regions.