Effect of hearing aids on cognitive functions in middle-aged and older adults with hearing loss: A systematic review and meta-analysis

Effects of Economic Status on Changes in Social Networks and Mental Health after Using Hearing Aids

OBJECTIVES

Hearing impairment affects social networks and mental health. Hearing aids (HA) can improve these deficits. However, their effects might be affected by various factors such as economic status (ES). This study aimed to identify how ES could moderate the effects of HA on social networks, depressive mood, and cognition.

METHODS

A prospective cohort for new HA users was established and classified into two groups based on their ES: a low ES group (LES group) and a medium to high ES group (MHES group). Audiological examination, Lubben social network scale-18 (LSNS-18), Short form of Geriatric Depression Score, Mini-Mental State Examination in the Korean version of the CERAD Assessment Packet, and surveys for satisfaction with HA were conducted before and at six months after wearing HA.

RESULTS

Post-HA application LSNS-18 scores were not improved in the LES group whereas they revealed significant improvement in the MHES group (p = 0.003). The LES group showed lower LSNS-18 score (p = 0.020) and its change (p = 0.042) than the MHES group. Additionally, patients with depressive moods in the MHES group showed better improvements than those in the LES group (p = 0.048). The effects of wearing HA on cognition and satisfaction with HA were not significantly different between the two groups.

CONCLUSIONS

HA did not improve social relationships and depressive moods in the LES group. Comprehensive and multidirectional support as well as hearing rehabilitation may be important for patients with LES.

LEVEL OF EVIDENCE

3 (Nonrandomized controlled cohort/follow-up study) Laryngoscope, 134:2387-2394, 2024.

GDF1 ameliorates cognitive impairment induced by hearing loss

Hearing loss is associated with an increased risk of Alzheimer disease (AD). However, the mechanisms of hearing loss promoting the onset of AD are poorly understood. Here we show that hearing loss aggravates cognitive impairment in both wild-type mice and mouse models of AD. Embryonic growth/differentiation factor 1 (GDF1) is downregulated in the hippocampus of deaf mice. Knockdown of GDF1 mimics the detrimental effect of hearing loss on cognition, while overexpression of GDF1 in the hippocampus attenuates the cognitive impairment induced by deafness. Strikingly, overexpression of GDF1 also attenuates cognitive impairment in APP/PS1 transgenic mice. GDF1 activates Akt, which phosphorylates asparagine endopeptidase and inhibits asparagine endopeptidase-induced synaptic degeneration and amyloid-β production. The expression of GDF1 is downregulated by the transcription factor CCAAT-enhancer binding protein-β. These findings indicate that hearing loss could promote AD pathological changes by inhibiting the GDF1 signaling pathway; thus, GDF1 may represent a therapeutic target for AD.

Cognitive change in prevalent and incident hearing loss: The Maastricht Aging Study

INTRODUCTION

Hearing loss (HL) has been associated with cognitive decline and dementia. We examined the temporal association between prevalent and incident HL and cognitive change.

METHODS

A total of 1823 participants (24-82 years) from the Maastricht Aging Study (MAAS) were assessed at baseline, 6 and 12 years, including pure-tone audiometry. Linear-mixed models were used to test the association between HL and cognition, adjusted for demographics and other dementia risk factors.

RESULTS

Participants with prevalent and incident HL showed a faster decline in verbal memory, information processing speed, and executive function than participants without HL. Decline was steady from baseline to 6 and 12 years for prevalent HL, but time-delayed from 6 to 12 years for incident HL. Having a hearing aid did not change associations.

DISCUSSION

Findings support the notion that HL is a risk factor for cognitive decline independent of other dementia risk factors. Onset of HL preceded onset of cognitive decline.

HIGHLIGHTS

We examined cognitive change in prevalent and incident hearing loss. Prevalent and incident hearing loss were associated with faster cognitive decline. For prevalent hearing loss, decline was steady from baseline to 6 and 12 years. Onset of hearing loss preceded the onset of cognitive decline. Having a hearing aid did not change the observed associations.

ENHANCE: a comparative prospective longitudinal study of cognitive outcomes after 3 years of hearing aid use in older adults

Background

With an aging population, the prevalence of hearing loss and dementia are increasing rapidly. Hearing loss is currently considered the largest potentially modifiable risk factor for dementia. The effect of hearing interventions on cognitive function should therefore be investigated, as if effective, these may be successfully implemented to modify cognitive outcomes for older adults with hearing loss.

Methods

This prospective longitudinal observational cohort study compared outcomes of a convenience sample of prospectively recruited first-time hearing aid users without dementia from an audiology center with those of community-living older adults participating in a large prospective longitudinal cohort study with/without hearing loss and/or hearing aids. All participants were assessed at baseline, 18 months, and 36 months using the same measures.

Results

Participants were 160 audiology clinic patients (48.8% female patient; mean age 73.5 years) with mild-severe hearing loss, fitted with hearing aids at baseline, and 102 participants of the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Aging (AIBL) (55.9% female patient; mean age 74.5 years). 18- and 36-month outcomes of subsets of the first participants to reach these points and complete the cognition assessment to date are compared. Primary comparative analysis showed cognitive stability for the hearing aid group while the AIBL group declined on working memory, visual attention, and psychomotor function. There was a non-significant trend for decline in visual learning for the AIBL group versus no decline for the hearing aid group. The hearing aid group showed significant decline on only 1 subtest and at a significantly slower rate than for the AIBL participants (p < 0.05). When education effects on cognitive trajectory were controlled, the HA group still performed significantly better on visual attention and psychomotor function (lower educated participants only) compared to the AIBL group but not on working memory or visual learning. Physical activity had no effect on cognitive performance trajectory.

Conclusion

Hearing aid users demonstrated significantly better cognitive performance to 3 years post-fitting, suggesting that hearing intervention may delay cognitive decline/dementia onset in older adults. Further studies using appropriate measures of cognition, hearing, and device use, with longer follow-up, are required.

Hearing Impairment and Cognitive Function: Mediating Role of Social Isolation and Depression

ObjectivesTo examine the relationship between hearing impairment and cognitive function and the mediating role of social isolation and depression. Methods: Data came from the 2018 China Health and Retirement Longitudinal Study wave. A self-reported item, a composite index, the 10-item Center for Epidemiological Studies Depression Scale, and the Mini-Mental State Exam were used to measure hearing impairment, social isolation, depression, and cognitive function, respectively. Mediation analysis was performed. Results: 6799 participants were included. For participants reporting mild hearing impairment and severe hearing impairment, there were significant direct and indirect effects on cognitive function. Social isolation mediated 2.75% and 6.33% of the relationship between mild hearing impairment, severe hearing impairment, and cognitive function, respectively. The direct effect of hearing impairment outweighed the mediation effect of social isolation on cognitive function. Conclusions: Decreased cognitive function linked to hearing impairment might benefit from addressing hearing impairment and social isolation in older adults.

Self-Reported Hearing Aid Use in Russian Adults According to a National Survey

BACKGROUND

Hearing loss is a significant public problem affecting 466 million people worldwide. Hearing-impaired persons benefit from the use of hearing aids, but the need is unmet in 85% of the global population. For the Russian population, no data have been found on this issue. The purpose of this study is to estimate the prevalence of hearing aid use in the Russian adult population.

METHODS

data on hearing aid use and self-reported trouble with hearing were obtained from the open access database of the Russia Longitudinal Monitoring Survey-Higher School of Economics (RLMS-HSE) for the years 1994-2021.

RESULTS

the prevalence of hearing aid use in Russian adults ranged from 4.3 per 1000 (95% CI 3.2-5.9) to 8.8 per 1000 (95% CI 7.5-10.2). The mean rate of self-reported trouble with hearing was 22.2% (SD 0.8); of them, 2.2% (SD 0.2) used hearing aids, and it strongly correlated with older age (r = 0.889) and more severe hearing issues (r = 0.938).

CONCLUSIONS

The overall prevalence of hearing aid use in Russian adults is very low with unmet needs in 98% of the cases of self-reported trouble with hearing, which is worse than in other populational studies and global estimates. The RLMS-HSE can be used for the monitoring of the national hearing health care system.

The impact of hearing loss on cognitive impairment: The mediating role of depressive symptoms and the moderating role of social relationships

Background

Given the potentially negative effects of hearing loss on mental health and cognitive function, it is critical to gain a better understanding of the mechanisms underlying the link between hearing loss and cognitive impairment. This study aimed to investigate the moderating effects of social relationships, including their components in the role of depressive symptoms as a mediator between hearing loss and cognitive impairment.

Methods

Cross-sectional analyses were conducted with 8,094 Chinese older adults (aged ≥65 years) from the Chinese Longitudinal Healthy Longevity Survey in 2018. Simple mediation analysis and moderated mediation analysis were conducted to examine the roles of depressive symptoms and social relationships in the association between hearing loss and cognitive impairment.

Results

There is a significant correlation between hearing loss, depressive symptoms, social relationships, and cognitive function. Depressive symptoms partially mediated the association between hearing loss and cognitive function [standardized regression B-coefficient (B) = -0.114; 95% confidence interval (CI): (-0.158, -0.076)]. Social relationships moderated the effect of hearing loss on cognitive function through both path b (depressive symptoms - cognitive function) [B = 0.021; 95% CI: (0.008, 0.034)], and path c' (hearing loss-cognitive function) [B = 0.597; 95% CI: (0.463, 0.730)]. Furthermore, social activities and social networks moderated both the direct and indirect effects of moderated mediation. However, there appeared to be no moderated effect of social support for both the direct and indirect paths.

Conclusion

Social relationships moderated both the direct and indirect effects of depressive symptoms on the association between hearing loss and cognitive impairment. These findings shed light on the mechanisms underlying the relationship between hearing loss and cognitive impairment in Chinese older adults. It might be worthwhile to recommend multidimensional health and social interventions aimed at improving mental health and social inclusion among older adults with hearing loss.