Age-Related Hearing Loss and Correlation with Cognitive Decline: a Narrative Review

Abstract

Age-related hearing loss (ARHL), also known as presbycusis, is one of the most prevalent long-term sensory difficulties in older people. It affects more than two-thirds of people over 70. In addition to communication challenges, ARHL has recently been revealed as a possible modifiable risk factor for cognitive decline and dementia. Comprehending this link is crucial for creating preventative interventions and maintaining healthy cognitive aging. This narrative review intended to analyze the evidence comprehensively relating age-related hearing loss (ARHL) with cognitive decline, define the possible pathophysiological mechanisms that may explain this association and assess the plausibility of hearing rehabilitation as a preventative therapy. A full literature search was done in PubMed, MEDLINE, Google Scholar and Frontiers databases employing the phrases "hearing loss" AND ("cognitive decline" OR "aging"). We only looked at articles that were published in English between 2014 and 2024 and were either systematic reviews, meta-analyses, or original research. We did not include any papers that were not peer-reviewed, not about people or not written in English. A total of 37 publications satisfied the inclusion criteria and underwent extensive review. There is strong evidence that ARHL is associated with rapid cognitive decline and an increased risk of dementia. Epidemiological studies suggest that hearing loss contributes to roughly 8–9% of worldwide dementia cases, which represents one of the primary modifiable risk factors. Some of the suggested ways that ARHL and cognitive decline are connected include through increased cognitive load, neuroplastic rearrangement, vascular dysfunction, oxidative stress and social isolation. Neuroimaging studies have revealed a reduction in gray matter and cortical atrophy in the auditory and associative areas of the brain in individuals with hearing loss. Hearing rehabilitation with hearing aids and cochlear implants has been connected to increased communication, higher social engagement and decreased cognitive decline; nevertheless, findings are rather inconsistent due to methodological errors and limited follow-up periods. Age-related hearing loss is a moderately widespread risk factor for cognitive decline and dementia that can be reduced. Early examination and effective auditory therapy can slow down cognitive decline and make life better for older people. Future longitudinal, multicenter and interventional studies are important to explain causal pathways, enhance intervention timing and assess cost-effective public health techniques for sustaining cognitive health in aging populations.

INTRODUCTION

Presbycusis, generally known as age-related hearing loss (ARHL), is a prevalent and sometimes misdiagnosed sensory condition that affects nearly two-thirds of individuals over the age of 70 (1). It is a slow, progressive and bilaterally symmetric sensorineural hearing loss that significantly limits the capacity to hear high-frequency stimuli. This makes it difficult to notice the difference between speech, especially in busy situations, but communication in tranquil places may still be good at first (1, 2). Early symptoms often show up as tiny issues with communicating that might develop as early as the fourth decade of life.

After arthritis and high blood pressure, ARHL is the third most frequent long-term health problem among senior people. An epidemiological study reveals that the frequency develops significantly with age, going from 3% in those aged 20 to 29 to 49% in those aged 60 to 69 and more than 80% in those aged 85 and beyond (3, 4). The illness drastically impairs communication, emotional well-being, cognitive function and general quality of life, establishing it as a serious public health problem.

The etiology of ARHL is multifaceted, showing the combined involvement of environmental and genetic variables. Chronic noise exposure, the use of ototoxic medicines, cardiovascular and metabolic illnesses (including atherosclerosis, diabetes and high blood pressure) and hereditary characteristics that influence the inner ear's capacity to adapt are all major contributors (5). Furthermore, oxidative stress, mitochondrial dysfunction, and persistent low-grade inflammation have been identified as biological factors that expedite cochlear and neuronal degeneration with advancing age (6, 7). If untreated, presbycusis may lead to social disengagement, depression and cognitive decline, all of which substantially affect functional independence and psychosocial well-being in older individuals (8).

Pathophysiology of ARHL

Age-related hearing loss is the outcome of accelerated aging of the cochlea and neurons, which is caused by both genetic factors and environmental and lifestyle impacts that last a lifetime (8). The illness is predominantly defined by degenerative anomalies in the cochlea and central auditory pathways, encompassing the loss of inner and outer hair cells, degeneration of spiral ganglion neurons, atrophy of the stria vascularis and diminished cochlear blood flow (6, 7).

These anomalies at the molecular level are connected to oxidative damage, mutations in mitochondrial DNA, glutamate excitotoxicity and concerns with calcium homeostasis. Together, these disorders generate synaptopathy and make it difficult for impulses to flow down the auditory nerve (6). Age-related vascular alterations and diminished endocochlear potential impede auditory transmission. Cortical rearrangement and impaired auditory neuronal plasticity beyond the periphery limit sound localization, temporal processing and speech perception.

Recent neuroimaging and neuropathological studies substantiate the idea of a "hearing-brain" continuum, indicating that age-related hearing loss (ARHL) correlates with reduced gray matter volume in the auditory cortex and temporal regions, alongside compensatory overactivation in prefrontal areas that facilitate listening effort (4, 9, 10). This sort of neuronal rearrangement makes it difficult to think and may help explain the association between ARHL and cognitive decline that has been described.

Pure tone audiometry is still the best way to measure hearing thresholds and find out what type and how substantial the hearing loss is (3). But because ARHL typically starts at high frequencies, diagnosing it early may include other audiological methods, such as speech-in-noise tests, otoacoustic emissions and auditory brainstem response (ABR) testing. These tests give a broader view of age-related hearing loss (4, 11).

Definition of cognitive decline

Cognitive decline is a gradual loss of memory, executive function, language, visuospatial ability and processing speed, which reveals deficiencies in many domains of neurocognitive function (12-14). These abnormalities may occur progressively, from moderate cognitive impairment (MCI), a transitional phase between normative aging and dementia, to more severe functionally crippling disorders such as Alzheimer's disease and vascular dementia.

Neurodegenerative processes that lead to cognitive decline have analogous pathophysiological paths to ARHL, such as oxidative stress, microvascular dysfunction, neuroinflammation and synaptic degradation (15, 16). Dementia, the most severe form of cognitive impairment, presently affects an estimated 46.8 million persons globally, a figure anticipated to reach 131.5 million by 2050. The whole economic cost is enormous, expanding from $818 billion in 2015 to an anticipated $2 trillion by 2050 (12).

Even as neurodegenerative research has gone a long way, there is still no therapy for dementia. This suggests that finding and managing risk factors such as hearing loss, high blood pressure, and diabetes is particularly critical for putting off the start of the illness and lowering its course (1, 17).

Background

Considering this backdrop, recognizing the link between auditory and cognitive aging has developed as a vital research requirement. The idea that age-related hearing loss (ARHL) leads to cognitive deterioration via common neuropathological pathways and heightened cognitive load is increasingly substantiated by recent investigations (9, 10, 18, 19). Numerous important cohort and meta-analytic studies have revealed that adults with untreated hearing loss have a 30-40% higher risk of quick cognitive decline and up to a threefold larger chance of getting dementia in comparison to those with normal hearing (9, 17, 20).

This narrative review seeks to synthesize and critically assess the existing literature on age-related hearing loss (ARHL) and cognitive decline, concentrating on the epidemiology and clinical relevance of ARHL in aging populations, the biological and psychosocial mechanisms connecting hearing impairment to cognitive decline, the evidence advocating for hearing rehabilitation as a potential preventive measure and the ramifications for clinical practice, research and public health policy.

A comprehensive search was done applying the PubMed, MEDLINE, Google Scholar and Frontiers databases. The search parameters were "hearing loss" AND "cognitive decline" OR "aging" and the results were limited to peer-reviewed English literature published between 2014 and 2024. Eligible papers included systematic reviews, meta-analyses and original research non-human studies, non-peer-reviewed studies and non-English studies were eliminated. After thorough screening and removing duplicates, 37 publications satisfied the requirements for qualitative synthesis.

This study tries to present a thorough synthesis of the database, revealing existing knowledge gaps and stressing the relevance of early identification and auditory rehabilitation in preserving cognitive health in older people.

REVIEW

Search results

This narrative review was conducted to examine the association between ARHL, presbycusis and cognitive decline. Four online databases – PubMed, Google Scholar, MEDLINE and Frontiers – were searched over a six-month period. The search strategy applied the Boolean logic: ("hearing loss") AND ("cognitive decline" OR "aging") (Figure.1).

Two independent reviewers conducted all stages of the screening process to ensure reliability and minimize bias. Initially, titles and abstracts were screened for relevance. Studies that met the preliminary criteria underwent full-text review. Discrepancies between reviewers were resolved by consensus, ensuring objectivity.

Inclusion criteria were: (1) peer-reviewed original research articles, systematic reviews, and meta-analyses; (2) studies published in English; and (3) publications within the last ten years (2014–2024). Exclusion criteria included: (1) non-human studies; (2) studies with small or unrepresentative sample sizes; (3) studies not focused on ARHL or cognitive decline; and (4) non-English studies or publications outside the 2014–2024 timeframe.

The structured and independent review process allowed for a transparent and reproducible methodology, reducing the risk of selection and subjective bias. Data extraction focused on study design, population characteristics, sample size, hearing assessment methods, cognitive outcome measures and main findings.

FIGURE 1.

Flow diagram of literature search

Epidemiological link between ARHL and cognitive decline

In the last 10 years, there have been a lot of studies on the association between hearing loss and cognitive decline (18, 21-24). Hearing impairment has become one of the most prominent modifiable risk factors for dementia, exceeding other proven contributors such as smoking, depression and social inactivity (9, 10, 17, 19). The 2020 Lancet Commission on Dementia Prevention stated that 8-9% of all dementia cases throughout the world might be associated with untreated hearing loss (9, 10).

Gallacher et al (25) conducted 17-year cohort research with 1,057 older males, revealing that those with hearing loss had roughly a threefold increased likelihood of acquiring dementia compared to those with normal hearing. In the same way, Loughrey et al (12) and Lau et al (26) established a dose-response connection, suggesting that a worse hearing loss predicted a quicker reduction in cognitive function. Recent studies of large populations, such as those by Lee et al (14) and Ford et al (27), backed up these results by demonstrating that untreated ARHL was associated with greater incidences of mild cognitive impairment and Alzheimer's disease on its own.

Addressing modifiable risk factors such as hearing loss, education, and cardiovascular health may delay or reduce the population-level incidence of dementia. Recent evidence from randomized trials, including the ACHIEVE study (2023) (28), supports that hearing rehabilitation can improve cognitive outcomes in older adults, highlighting the role of auditory interventions as part of multifactorial strategies (29).

Suggested mechanisms connecting ARHL and cognitive decline

Despite the consistent epidemiological findings, the causal routes between ARHL and cognitive decline are now being studied (9, 30-32). There are four primary categories of complementary processes that have been suggested: neurobiological, cognitive, vascular/metabolic and psychosocial.

1. Neurobiology and the common cause hypothesis

The "common cause theory" posits that both ARHL and cognitive impairment are created by the same neurodegenerative process in the brain as it matures (4, 5, 19). Age-associated declines in cortical thickness, gray matter volume, and white matter integrity have been found in both auditory and cognitive domains (9, 30). Structural MRI studies reveal reduction of the superior temporal gyrus and hippocampus, indicating that hearing loss may aggravate or increase neuropathological problems associated with dementia (29, 30).

Biological processes that are going on include oxidative stress, mitochondrial malfunction, vascular dysregulation, glutamate excitotoxicity and the creation of inflammatory cytokines (16). These processes cumulatively create damage to neurons and impair the brain's ability to adapt, making the auditory and cognitive networks more prone to the repercussions of aging.

2. Cognitive load theory

The cognitive load theory suggests that hearing impairment enhances the mental effort necessary to grasp degraded auditory information, consequently reallocating cognitive resources from advanced processing capacities, including memory, attention and executive function (5). Functional MRI studies have indicated that people with hearing loss have increased activity in the prefrontal cortex while they are listening to anything. This is because their brains are engaging in different regions to help them comprehend what they are hearing (9). Over time, this frequent shift of resources may generate cognitive weariness and a lower reserve capacity, which might hasten up loss in areas other than auditory processing (3, 33, 34).

3. The psychological and social isolation pathway

Social isolation and loneliness have surfaced as crucial mediators in the ARHL-cognition link (Figure 2) (3-5, 16). Older people with hearing loss generally have trouble communicating, which makes them less inclined to connect with others, feel depressed and have less cognitive stimulation. In long-term care conditions, people with severe hearing impairment demonstrate a 1.4 times increased risk of poor social engagement and a 1.3 times bigger chance of minimum involvement in social activities (3). These conditions contribute to rapid cognitive impairment through both psychological and neurobiological processes, such as increased cortisol levels and hippocampus atrophy.

FIGURE 2.

Chart with the countries from which came the articles included in this review

4. Vascular and metabolic pathways

ARHL is also tied to microvascular insufficiency and endothelial dysfunction, which are additional illnesses that are related to vascular contributions to cognitive impairment and dementia (VCID) (16). Hypertension, diabetes and dyslipidemia are all risk factors that are associated with this. Vascular degeneration in the cochlea and cerebral microcirculation may concurrently impair auditory and cognitive neuronal networks, substantiating the concept that age-related hearing loss (ARHL) is a component of a systemic aging phenotype (4, 16, 30).

In older adults, age-related hearing loss often coexists with vestibular dysfunction, such as dizziness or vertigo, increasing the sensory and cognitive burden of aging. Auditory and vestibular impairments share common pathophysiological mechanisms, including microvascular insufficiency, neurodegeneration and impaired central compensation. As highlighted by Musat et al (2025) (35), inferior vestibular neuritis in elderly patients is associated with delayed vestibular compensation, persistent balance disturbances and coexisting sensorineural hearing loss, which may increase cognitive load, fall risk and accelerate functional and cognitive decline.

FIGURE 3.

Conceptual framework illustrating the correlation between ARHL and cognitive deterioration (5)

The effect of hearing rehabilitation on cognitive results

A new study reveals that correcting hearing loss may slow down or decrease cognitive deterioration. A large meta-analysis indicated that those using hearing aids demonstrated a 19% decreased chance of long-term cognitive impairment in comparison to non-users (17). Shukla et al revealed that older individuals who used amplification devices had greater memory test scores, speech comprehension, and social involvement than those who did not use them and had untreated hearing loss (36).

Recent longitudinal research by West et al found that consistent hearing aid usage was linked with a slowing of cognitive decline and improved functional outcomes, but the level of effect was dependent on adherence and beginning cognitive condition (37). Moreover, cochlear implantation has proven efficacy in restoring auditory input for patients with severe to profound sensorineural hearing loss, consequently boosting communication and quality of life, and in particular trials, augmenting global cognition (38).

However, outcomes continue to be diverse. Some studies indicate that the advantages are minor or only last for a short duration. This is because the studies were set up differently, employed distinct cognitive tests and included other criteria that may change the results, such as education, wealth and other health concerns (30, 39). It is also vital to underline that hearing aids and cochlear implants are not utilized enough, especially by older persons with lower finances, even if there is research suggesting they can help with cognitive and social concerns (17, 39).

Importance for public health and clinical use

Since ARHL and dementia regularly coexist, including auditory screening in geriatric and memory care processes may be crucial for the early identification of at-risk people. Hearing restoration not only increases communication but may also bolster cognitive resilience by retaining neuronal stimulation and social interaction (11, 30, 40, 41).

From a social standpoint, untreated hearing loss incurs significant economic and healthcare expenditures due to its relationship with disability, depression, falls, and cognitive impairment. As the world's population becomes older, taking care of both sensory and cognitive health is a simple technique to prevent complications. Policymakers and doctors should thus treat hearing rehabilitation as an important component of a complete dementia prevention approach, in conjunction with vascular risk management, physical activity and cognitive engagement programs.

Barriers to adoption of hearing aids

Barriers to the adoption of hearing aids include high costs, limited access to audiological services, social stigma, and low awareness of the benefits of hearing rehabilitation. Additionally, perceived inconvenience or discomfort and lack of professional guidance can further hinder their widespread use among older adults (42).

A systematic review and meta-analysis (43), indicated that older adults with low income residing in rural areas demonstrated the lowest prevalence of hearing aid use, whereas higher-income individuals in rural settings exhibited the highest utilization rates. These findings suggest that financial limitations, restricted access to audiological healthcare services, the high cost of hearing aids, social stigma and transportation barriers represent significant obstacles, particularly among low-income rural populations.

Sociocultural determinants of both ARHL and dementia

Sociocultural determinants play a pivotal role in both the development and progression of age-related hearing loss (ARHL) as well as cognitive decline and dementia. Factors such as lower educational attainment and socioeconomic status, cultural perceptions of aging and hearing loss, social stigma, and reduced social participation limit access to healthcare services and adherence to hearing rehabilitation interventions, thereby exacerbating social isolation and increasing the risk of cognitive deterioration (44-45). Consequently, addressing these sociocultural inequalities is essential for the development of effective, equitable and population-tailored prevention and intervention strategies.

Pros and cons of the current review

This review synthesizes and critically reviews 10 years of research studying the ARHL-cognition relationship, spanning epidemiological, mechanistic and interventional data. By blending systematic reviews, meta-analyses, and original research, it gives a thorough picture of the relationship and explains how it may be applied in therapy. The thorough, dual-author screening process prevents prejudice and ensures that approaches are consistent. Including a wide range of research populations also makes the results more generalizable.

Nonetheless, constraints exist. The review, being a secondary evaluation of available literature, is vulnerable to publication bias and heterogeneity among the included research. Including non-English and gray literature may have provided vital information. Furthermore, proving causation is challenging due to the prevalence of observational designs. Longitudinal, multicenter studies should be the focus of future research to analyze causative pathways, look at the timing and length of therapy, and examine neurobiological alterations that occurred after hearing rehabilitation.

CONCLUSIONS

Cognitive decline and dementia represent major global public health challenges, with significant social and economic repercussions for aging populations. Age-related hearing loss (ARHL) is increasingly recognized as a significant, independent and potentially modifiable risk factor for cognitive decline, extending beyond a mere sensory change associated with aging. Through shared pathophysiological mechanisms, including vascular and oxidative damage, neuroinflammation, and reduced neuroplasticity, as well as psychosocial factors such as social isolation and increased cognitive load, ARHL contributes to the deterioration of cognitive function. Accumulating evidence consistently demonstrates that untreated hearing loss is associated with accelerated cognitive decline and an elevated risk of dementia, supporting a model of shared pathology between auditory and cognitive aging.

Concurrently, a growing body of research suggests that hearing rehabilitation – via hearing aids, cochlear implants and auditory training – may support cognitive preservation, enhance social participation, and slow cognitive deterioration. Although current evidence is predominantly observational and methodologically heterogeneous, the overall findings underscore auditory rehabilitation as a promising preventive strategy against dementia. Therefore, the integration of regular audiological assessments into primary and geriatric care, alongside the promotion of accessible hearing health policies, is recommended. Future research should prioritize longitudinal and interventional studies to establish causal relationships.

Conflicts of interest

none declared.

Financial support

none declared.

Authors' contributions

AL – conceptualization, methodology, formal analysis' AL, IM – data curation, writing (original draft preparation); AL, IM, EK, NSB – writing (review and editing); AL – supervision.