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

The Association between Untreated and Treated Hearing Loss and Cognitive Performance in Men and Women Aged 60-96 Years: Data from the Swedish "Good Aging in Skåne" Population Study

Background/Objectives: Recent decades have witnessed a sharp increase in research investigating the association between hearing loss and cognitive impairment. Few previous studies have stratified for sex when investigating this issue, where results were inconsistent and require further clarification. Thus, the objective was to investigate the association between self-reported hearing loss and levels of cognitive impairment, stratified for sex. Methods: In this cross-sectional study, data were collected from 2001 to 2016. The study sample consisted of 5075 individuals, 2325 (45.8%) men, mean age 68.3 years, and 2750 (54.2%) women, mean age 70.0 years. Multiple variate ordinal regression models were constructed and adjusted for age, marital status, education, physical activity, depressive mood, hypertension, stroke, diabetes, and use of sedatives to investigate associations between groups of self-reported untreated and treated hearing loss and those reporting no hearing loss in relation to levels of cognitive impairment assessed by the Mini-Mental State Examination scale. Results: In men, treated hearing loss was associated with levels of cognitive impairment, odds ratio (OR) = 1.64, 95% confidence interval (CI) = 1.14-2.36. In women, both untreated hearing loss, (OR = 1.45, CI 1.07-1.98) and treated hearing loss (OR= 1.46, CI 1.06-2.04) were associated with levels of cognitive impairment. Conclusions: Hearing loss was found to be associated with cognitive impairment despite hearing aid use as well as awareness amongst physicians. The introduction of screening programs for hearing loss in older adults could be a crucial step for earlier identification of individuals at higher risk of developing cognitive impairment and dementia.

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.

Audiometric Findings in Senior Adults of 80 Years and Older

Objective

To examine hearing thresholds in senior adults of 80 years and older and compare this data to the current ISO 7029 reference values.

Design

A descriptive, prospective study testing pure-tone and speech audiometry in senior adults participating in the BUTTERFLY study or the BrUssels sTudy on The Early pRedictors of FraiLtY. A Gerontological study to identify determinants for active aging and for early stages of frailty in the oldest population. Using the formula given by ISO 7028:2017 the median value of hearing was calculated based on the sex and age of the participant and compared to the measured hearing thresholds.

Results

151 senior adults were included. The prevalence of hearing loss was 90.7% (PTA > 20 dB HL). The results were compared to the mean ISO values, calculated for every participant. Both males and females in our study population had worse hearing thresholds than could be expected based on the ISO reference values. In our study population with moderate hearing loss (PTA > 40 dB HL), 38% is underserved in term of hearing restoration healthcare and yet another 38% is unsatisfied with the result of the hearing aids. Given the vast impact on the individual and society, this is a problem in need of our attention.

Conclusion

The ISO 7029 reference values may be an underestimation of hearing loss in senior adults of 80 years and older. Therefore we present a statistical distribution of hearing thresholds on different frequencies related to age and sex that can be used as a baseline for further development of the reference values.