Dementia in a Hearing-impaired Population According to Hearing Aid Use: A Nationwide Population-based Study in Korea

Physical Inactivity and Sedentariness in Older Hearing Loss patients: Restoration With Hearing Aids

OBJECTIVES

Hearing loss causes numerous functional deficits. However, few studies have been conducted to assess the association between hearing loss and physical inactivity. This study aimed to evaluate the physical activity and sedentary behavior of hearing loss patients and their relation with the use of hearing aids.

MATERIALS AND METHODS

We extracted participants over 60 years of age with information on hearing status and physical activities from the eighth Korea National Health and Nutritional Examination Survey conducted from 2019 to 2020. We classified them into four groups: a normal hearing group (≤25 dB), a mild hearing loss group (>25 dB and ≤40 dB), a moderate hearing loss group (>40 dB and ≤50 dB), and a non-serviceable hearing group (>50 dB). Additionally, we extracted hearing aid users with hearing levels exceeding 50 dB.

RESULTS

After adjusting other factors, the non-serviceable hearing group walked less frequently than the moderate (p = 0.004) and mild hearing loss group (p < 0.001) and walked less and sat more than the normal hearing group (walking frequency: p < 0.001; walking time: p = 0.020; and sitting time: p = 0.034). Also, the hearing aid users walked more frequently (p = 0.003) and for longer (p = 0.045) than the non-serviceable hearing group.

CONCLUSION

Hearing loss is associated with reduced walking and a sedentary lifestyle. The use of hearing aids is associated with improved physical activity. Appropriate interventions, including hearing aids, should be provided to hearing loss patients.

LEVEL OF EVIDENCE

3 (individual cross-sectional study) Laryngoscope, 2024.

Assessing the accuracy and reliability of application-based audiometry for hearing evaluation

Pure-tone audiometry (PTA) is the gold standard for assessing hearing loss. However, traditional PTA tests require specialized equipment, trained personnel, and a soundproof environment. Recently, smartphone-based PTA tests have been developed as an alternative method for hearing assessment. The aim of this study was to validate the accuracy and reliability of a smartphone application-based audiometry test. This study was conducted to assess the performance of application-based audiometry from November 2021 to January 2022. Pure-tone thresholds were measured using a smartphone application-based PTA test and compared with results obtained using a traditional audiometer in a sound-treated booth. The smartphone application used in this study was the "Care4Ear (Care4ear, version 1.0.6, MIJ Co., Ltd.)". Hearing thresholds less than 35 dB HL were classified as group A, 35-64 dB HL as group B, and 65 dB HL or greater as group C for the classification of hearing levels. We evaluated the accuracy of smartphone audiometry for each group and compared the results of frequency-specific hearing tests. Additionally, we examined the results of smartphone audiometry in individuals (n = 27) with asymmetric hearing loss. Seventy subjects completed both conventional audiometry and smartphone application-based hearing tests. Among the ears assessed, 55.7% were classified as group A, while 25.7% and 18.6% were classified as group B and group C, respectively. The average hearing threshold obtained from conventional pure-tone audiometry was 37.7 ± 25.2 dB HL, whereas the application-based hearing test yielded thresholds of 21.0 ± 23.0 dB HL. A significant correlation (r = 0.69, p < 0.01) was found between the average hearing thresholds obtained from the application-based and conventional pure-tone audiometry tests. The application-based test achieved a 97.4% hit rate for classifying hearing thresholds as class A, but lower rates of 22.2% for class B and 38.5% for class C. Notably, a discrepancy was observed between the hearing threshold measured by the application and the conventional audiometry for the worse ear with asymmetric hearing. The smartphone-based audiometry is a feasible method for hearing evaluation especially in persons with normal hearing. In cases of hearing loss or asymmetric hearing loss, the results of the application-based audiometry may be inaccurate, limiting its diagnostic utility.

Umbrella review and Delphi study on modifiable factors for dementia risk reduction

A 2013 systematic review and Delphi consensus study identified 12 modifiable risk and protective factors for dementia, which were subsequently merged into the "LIfestyle for BRAin health" (LIBRA) score. We systematically evaluated whether LIBRA requires revision based on new evidence. To identify modifiable risk and protective factors suitable for dementia risk reduction, we combined an umbrella review of systematic reviews and meta-analyses with a two-round Delphi consensus study. The review of 608 unique primary studies and opinions of 18 experts prioritized six modifiable factors: hearing impairment, social contact, sleep, life course inequalities, atrial fibrillation, and psychological stress. Based on expert ranking, hearing impairment, social contact, and sleep were considered the most suitable candidates for inclusion in updated dementia risk scores. As such, the current study shows that dementia risk scores need systematic updates based on emerging evidence. Future studies will validate the updated LIBRA score in different cohorts. HIGHLIGHTS: An umbrella review was combined with opinions of 18 dementia experts. Various candidate targets for dementia risk reduction were identified. Experts prioritized hearing impairment, social contact, and sleep. Re-assessment of dementia risk scores is encouraged. Future work should evaluate the predictive validity of updated risk scores.

Hearing Loss, Hearing Aid Use, and Risk of Dementia in Older Adults

Importance

Hearing loss has been suggested as a risk factor for dementia, but there is still a need for high-quality research to better understand the association between these 2 conditions and the underlying causal mechanisms and treatment benefits using larger cohorts and detailed data.

Objective

To investigate the association between hearing loss and incident dementia, as well as how hearing aid use contributes to this association.

Design, Setting, and Participants

This population-based cohort study was conducted in Southern Denmark between January 2003 and December 2017 and included all residents 50 years and older. We excluded all persons with dementia before baseline as well as those who did not live in the region 5 years before baseline, with incomplete address history, or who had missing covariate information.

Exposures

Individual hearing status based on the Hearing Examinations in Southern Denmark database, which contains data on all pure-tone audiometry examinations performed at public hearing rehabilitation clinics in Southern Denmark.

Main Outcomes and Measures

Incident cases of dementia and Alzheimer disease as identified from national registries.

Results

The study population comprised 573 088 persons (298 006 women [52%]; mean [SD] age, 60.8 [11.3] years) with 23 023 cases of dementia and mean (SD) follow-up of 8.6 (4.3) years. Having a hearing loss was associated with an increased risk of dementia, with an adjusted hazard ratio (HR) of 1.07 (95% CI, 1.04-1.11) compared with having no hearing loss. Severe hearing loss in the better and worse ear was associated with a higher dementia risk, with an HR of 1.20 (95% CI, 1.09-1.32) and 1.13 (95% CI, 1.06-1.20), respectively, compared with having no hearing loss in the corresponding ear. Compared with people without hearing loss, the risk of dementia was higher among people with hearing loss who were not using hearing aids than those who had hearing loss and were using hearing aids, with HRs of 1.20 (95% CI, 1.13-1.27) and 1.06 (95% CI, 1.01-1.10), respectively.

Conclusions and Relevance

The results of this cohort study suggest that hearing loss was associated with increased dementia risk, especially among people not using hearing aids, suggesting that hearing aids might prevent or delay the onset and progression of dementia. The risk estimates were lower than in previous studies, highlighting the need for more high-quality longitudinal studies.

Does social isolation mediate the association between hearing loss and cognition in adults? A systematic review and meta-analysis of longitudinal studies

Background

There has been extensive research on the relationship between hearing and cognitive impairment in older adults but little examination of the role of mediating factors. Social isolation is a potential mediator, occurring because of hearing loss, and contributing to accelerated cognitive decline. Previous systematic reviews on this topic area have not considered the temporal nature of hearing loss and cognitive impairment exclusively or examined potential mediators within a longitudinal study design.

Methods

A systematic review was conducted. Electronic searches were performed in Web of Science, PubMed (Medline), Scopus, EMBASE, PsychInfo, and ProQuest (PsychArticles and ProQuest Dissertation and Theses) based on a search string of keywords relating to hearing loss, social isolation, and cognitive impairment/dementia in June 2023. Papers were critically appraised using the CASP checklists for cohort studies. Risk of bias in the selected studies was assessed using the Item Bank for Assessment of Risk of Bias and Precision for Observational Studies of Interventions or Exposures.

Results

Eleven of the 15 included studies provide evidence of a dose-dependent association between hearing threshold (40 dB HL or greater) and later cognitive impairment or incident dementia. Only one study included social isolation as a mediator, which was found to not be a significant contributing factor. The meta-analysis of 5 studies pooled hazard ratio for cognitive impairment due to hearing loss is 1.11 (95% CI: 1.06 to 1.15, p < 0.001). The pooled hazard ratio for incident dementia due to hearing loss was HR 1.21 (95% CI: 1.11 to 1.31, p = 0.002).

Conclusion

The analysis of included studies indicate that hearing threshold level affects later cognitive status or dementia diagnosis. There is not enough evidence to determine the role of social isolation as a mediator. Future epidemiology studies need to measure different elements of social isolation and ensure that hearing and cognition are measured at multiple time points.

Increased Risk of Dementia Following a Diagnosis of Hearing Impairment: A South Korean Nationwide Cohort Study

BACKGROUND

Among the older adults, hearing impairment is a common problem and may contribute to dementia.

OBJECTIVE

Therefore, we aimed to examine the association between hearing impairment and the risk of dementia among older adults in South Korea.

METHODS

Using the Korean National Health Insurance Service-Senior Cohort from 2005 to 2019, we collected data of 44,728 patients. Hearing impairment was determined using the national disability registry. Propensity score matching (1:1) was performed to match patients with and without hearing impairment (case: 22,364, control: 22,364). A Cox proportional hazards regression model was built to analyze the association between hearing impairment and dementia.

RESULTS

Patients with hearing impairment had a higher risk of dementia than those without hearing impairment (hazard ratio [HR] = 1.28, 95% confidence interval [CI] = 1.23-1.34). Assessing the degree of disability, both severe (HR = 1.25, 95% CI = 1.16-1.35) and mild conditions (HR = 1.29, 95% CI = 1.23-1.35) had an increased risk of dementia, respectively.

CONCLUSIONS

Older patients with hearing impairment exhibit an increased risk of dementia, thereby warranting a new approach to dementia care among these patients regardless of the degree of hearing impairment.

Hearing loss and its link to cognitive impairment and dementia

Hearing loss is an important risk factor for the development of dementia, particularly Alzheimer's disease (AD). Mid-life hearing loss increases the risk of developing dementia by double any other single factor. However, given this strong connection between hearing loss and AD, the mechanisms responsible for this link are still unknown. Data from observational studies relating hearing loss and cognitive impairment, measured with standardized questionnaires, has shown a strong relationship between them. Similar findings have emerged from animal studies, showing that the induction of hearing loss via prolonged loud sound exposure or ear canal blocking, can impair cognitive abilities. Interestingly, patients with age-related hearing impairment exhibit increased phosphorylated tau in the cerebrospinal fluid, but no such relationship has been identified for amyloid-β. In addition, hearing loss predisposes to social isolation precipitating the development of dementia through a supposed reduction in cognitive load and processing requirements. Given this link between hearing loss and dementia, the question arises whether the restoration of hearing might mitigate against the onset or progress of AD. Indeed, there is a growing body of research that suggests that those who wear hearing aids for age-related hearing problems maintain better cognitive function over time than those who do not. These are compelling findings, as they suggest the use of hearing aids has the potential to be a cost-effective treatment for those with hearing loss both prior (for those at high risk for AD) and after the development of symptoms. This review aims to summarize the current theories that relate hearing loss and cognitive decline, present the key findings of animal studies, observational studies and summarize the gaps and limitations that need to be addressed in this topic. Through this, we suggest directions for future studies to tackle the lack of adequately randomized control trials in the field. This omission is responsible for the inability to provide a conclusive verdict on whether to use hearing interventions to target hearing-loss related cognitive decline.

Do hearing loss interventions prevent dementia?

Hearing loss has been identified as a potentially modifiable risk for dementia. This discussion paper reviews studies examining the impact of hearing loss interventions on cognitive decline and incident cognitive impairment, identified the challenges for research on the cognitive impacts of hearing interventions, and the likely benefits of hearing interventions for healthy aging and mental well-being.

Dementia and hearing-aid use: a two-way street

OBJECTIVES

Hearing-aid use may reduce risk of dementia, but cognitive impairment makes use more challenging. An observed association between reduced hearing-aid use and incident dementia could reflect either or both of these causal paths. The objective was to examine the effects of each path while minimising contamination between paths.

METHODS

Health records data from 380,794 Veterans who obtained hearing aids from the US Veterans Affairs healthcare system were analysed. Analysis 1 (n = 72,180) used multivariable logistic regression to model the likelihood of incident dementia 3.5-5 years post hearing-aid fitting for patients free of dementia and mild cognitive impairment (MCI). Analysis 2 (n = 272,748) modelled the likelihood of being a persistent hearing-aid user at 3 years 2 months after fitting, contrasting subgroups by level of cognitive function at the time of fitting. Analysis time windows were optimized relative to dataset constraints. Models were controlled for available relevant predictors.

RESULTS

The adjusted OR for incident dementia was 0.73 (95% CI 0.66-0.81) for persistent (versus non-persistent) hearing-aid users. The adjusted OR for hearing-aid use persistence was 0.46 (95% CI 0.43-0.48) in those with pre-existing dementia (versus those remaining free of MCI and dementia).

CONCLUSION

Substantial independent associations are observed in both directions, suggesting that hearing-aid use decreases risk of dementia and that better cognitive function predisposes towards persistent use. Research studying protective effects of hearing-aid use against dementia needs to account for cognitive status. Clinically, hearing devices and hearing care processes must be accessible and usable for all, regardless of their cognitive status.

The trend in adoption of hearing aids following changes in provision policy in South Korea

The Korean government started to cover part of the price of hearing aids ($200) for individuals with hearing disabilities in 1997, and the reimbursement for a hearing aid increased in 2005 ($300) and again in 2015 ($1000). The aim of this study was to evaluate the annual trend of newly-registered individuals with hearing disability according to the changes of the hearing aid provision scheme. Subjects with newly-registered hearing disabilities were assessed using Korean National Health Insurance Service (KNHIS) data from January 1, 2004, to December 31, 2018. A total of 271,742 individuals were newly registered during the index period. Records of hearing aid prescriptions and hearing aid subsidies were used to assess the adoption of hearing aids. This study also assessed the intervals between registration of hearing disability and the adoption of hearing aids, as well as the number of hearing aid subsidies provided. From 2004 to 2009 there was a slight increase in the number of individuals newly registered with hearing disabilities, and from 2011 to 2015, the number showed a tendency to decrease. Then, from 2015, the number of individuals with hearing disabilities increased abruptly, and the proportion of subjects receiving hearing aid subsidies also increased. Between 2004 and 2018, the time interval from hearing disability registration to hearing aid adoption showed a decreasing trend. We conclude that the annual number of individuals with newly-registered hearing disabilities is affected by the level of the hearing aid subsidy, and there is much unregistered or unaddressed hearing loss prior to the introduction of realistic hearing aid provision.