A pilot randomized controlled trial of hearing aids to improve mood and cognition in older adults

What impact does hearing impairment have on cognitive health in older married couples in China?

Hearing impairment is a common geriatric health problem and chronic stressor, and it is associated with poor cognitive outcomes. However, little is known about the impact of hearing impairment in married couples, particularly its potential spillover effects on the cognitive health among spouses of individuals with impairment. Drawing on a stress-proliferation perspective, we used actor-partner interdependence models to examine (1) whether an individual's hearing impairment influences their spouse's cognitive function; and (2) whether AL, symptoms of depression, and social participation serve as mediators for such an association. We utilized data from the 2015 (baseline) and 2018 (3-year follow-up) waves of the China Health and Retirement Longitudinal Study. 4434 couples were included at baseline, and 2190 couples remained after the 3-year follow-up. Hearing impairment among married women was associated with negative impacts on their spouses' cognitive function. Symptoms of depression and social participation may have served as potential mediators in this relationship. For married men, there was no statistically significant association between hearing impairment and spouses' cognitive function. Our findings suggest that hearing impairment among one spouse can lead to negative impacts on the other, but that this effect may depend on gender. Early diagnosis and couple-based interventions for hearing impairment are important for the cognitive health of both hearing-impaired individuals and their spouses.

Hearing Loss in Older People With Schizophrenia: Audiologic Characteristics and Association With Psychosocial Functioning

OBJECTIVE

The severity and impact of hearing deficits among adults with schizophrenia spectrum disorders may become increasingly relevant with advancing age. This study evaluated hearing ability and associated psychosocial functioning among older adults aged 50-70.

DESIGN

Cross-sectional analysis.

SETTING

Four outpatient psychiatry clinics in New York City.

PARTICIPANTS

Individuals aged 50-70 years with diagnoses of schizophrenia or schizoaffective disorder.

MEASUREMENTS

Unaided pure tone air conduction audiometry conducted using a portable audiometry system determined the pure tone average (PTA) hearing threshold across four frequencies: 500, 1k, 2k, and 4k Hz. Better ear PTA defined the hearing threshold. Audiometry data retrieved from the U.S. National Health and Nutrition Examination Survey aided interpretation of sample hearing loss rates. Standard measures evaluated psychiatric symptoms, perceived impact of hearing impairment, loneliness, and quality of life.

RESULTS

Among audiometry completers (N = 40), 35% (n = 14) demonstrated subclinical hearing loss (16-25 dB) and 35% (n = 14) had mild or worse hearing loss (≥26 dB). Rates were higher than expected based on age-based population data. Those who perceived hearing handicap rated it moderate (12.2%) or severe (7.3%); those who perceived tinnitus rated the impact as mild to moderate (12.2%) or catastrophic (2.4%). Neither psychiatric symptoms nor interviewer-rated quality of life was associated with hearing ability. Greater loneliness was significantly correlated with worse audiologic performance (r = 0.475, p <0.01) and greater perceived hearing handicap (r = 0.480, p <0.01).

CONCLUSION

Identifying the need for hearing loss treatment among aging adults with schizophrenia spectrum disorders is important given the potential implications for social functioning, cognitive, and mental health.

Update on modifiable risk factors for Alzheimer's disease and related dementias

PURPOSE OF REVIEW

All human beings undergo a lifelong cumulative exposure to potentially preventable adverse factors such as toxins, infections, traumatisms, and cardiovascular risk factors, collectively termed exposome. The interplay between the individual's genetics and exposome is thought to have a large impact in health outcomes such as cancer and cardiovascular disease. Likewise, a growing body of evidence is supporting the idea that preventable factors explain a sizable proportion of Alzheimer's disease and related dementia (ADRD) cases.

RECENT FINDINGS

Here, we will review the most recent epidemiological, experimental preclinical, and interventional clinical studies examining some of these potentially modifiable risk factors for ADRD. We will focus on new evidence regarding cardiovascular risk factors, air pollution, viral and other infectious agents, traumatic brain injury, and hearing loss.

SUMMARY

While greater and higher quality epidemiological and experimental evidence is needed to unequivocally confirm their causal link with ADRD and/or unravel the underlying mechanisms, these modifiable risk factors may represent a window of opportunity to reduce ADRD incidence and prevalence at the population level via health screenings, and education and health policies.

Measuring Multidimensional Aspects of Health in the Oldest Old Using the NIH Toolbox: Results From the ARMADA Study

OBJECTIVE

The percentage of older adults living into their 80s and beyond is expanding rapidly. Characterization of typical cognitive performance in this population is complicated by a dearth of normative data for the oldest old. Additionally, little attention has been paid to other aspects of health, such as motor, sensory, and emotional functioning, that may interact with cognitive changes to predict quality of life and well-being. The current study used the NIH Toolbox (NIHTB) to determine age group differences between persons aged 65-84 and 85+ with normal cognition.

METHOD

Participants were recruited in two age bands (i.e., 65-84 and 85+). All participants completed the NIHTB Cognition, Motor, Sensation, and Emotion modules. Independent-samples t-tests determined age group differences with post-hoc adjustments using Bonferroni corrections. All subtest and composite scores were then regressed on age and other demographic covariates.

RESULTS

The 65-84 group obtained significantly higher scores than the 85+ group across all cognitive measures except oral reading, all motor measures except gait speed, and all sensation measures except pain interference. Age remained a significant predictor after controlling for covariates. Age was not significantly associated with differences in emotion scores.

CONCLUSIONS

Results support the use of the NIHTB in persons over 85 with normal cognition. As expected, fluid reasoning abilities and certain motor and sensory functions decreased with age in the oldest old. Inclusion of motor and sensation batteries is warranted when studying trajectories of aging in the oldest old to allow for multidimensional characterization of health.

Assessing the feasibility of a randomised controlled trial examining the effect of hearing aids on cognitive decline in elderly individuals: a study protocol

INTRODUCTION

Hearing loss is one of the leading potentially modifiable risk factors for dementia. There is growing evidence suggesting that treating hearing loss with hearing aids could be a relatively low-cost intervention in reducing cognitive decline and the risk of dementia in the long term. However, given the current constraints of the limited evidence, it is premature to draw definitive conclusions about the effect of hearing aids on cognitive functioning. More long-term randomised studies examining this effect would be recommended. Prior to embarking on large-scale lengthy randomised controlled trials (RCTs), it is imperative to determine the viability of such studies. Therefore, the purpose of the current study is to assess the feasibility of a RCT that investigates the effect of hearing aids on cognitive functioning in elderly hearing impaired individuals.

METHODS AND ANALYSIS

In this randomised controlled feasibility trial, 24 individuals aged 65 years or older with mild to moderate hearing loss (≥35-<50 dB pure tone average (0.5-4 kHz) unilateral or bilateral) will be included and randomised towards a hearing aid intervention or no intervention. At baseline and at 6-month follow-up, a test battery consisting of cognitive tests and questionnaires will be administered to both groups. The primary outcome of the study is the willingness of hearing impaired individuals to be randomised for hearing amplification in a study regarding cognition. The secondary outcomes are the feasibility of the test battery and the therapy compliance of hearing aid use.

ETHICS AND DISSEMINATION

This research protocol was approved by the Institutional Review Board of the University Medical Centre Utrecht (NL80594.041.22, V.3, January 2023). The trial results will be made accessible to the public in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ISRCTN84550071.

Dementia and Hearing Aid Use and Cessation: A National Study

PURPOSE

The current standard for management of hearing loss in the United States involves the use of a hearing aid. Anecdotal evidence suggests that the use of a hearing aid may be less effective in the context of dementia, though national data on use and cessation are not described.

METHOD

This longitudinal analysis of the National Health and Aging Trends Study followed participants who self-reported hearing aid use to estimate risk of hearing aid cessation over 9 years. We examine whether hearing aid cessation differs by dementia status using generalized estimating equations logistic regression accounting for loss to follow-up. Supplemental analyses were undertaken to examine the contribution of caregiving and environmental factors on hearing aid cessation.

RESULTS

Of 1,310 older adults who reported hearing loss (25% 80-84 years, 51% women, 74% White), 22% with dementia and 57% baseline hearing aid use. Dementia increased likelihood of ceasing hearing aid use during the first year after adoption (OR = 2.07, 95% CI [1.33, 3.23], p interaction = .11). In later years, older adults with either a previous or recent diagnosis of dementia had a 95% higher odds of hearing aid cessation (OR = 1.95, 95% CI [1.31, 2.90]), a decrease in odds with respect to the first year after adoption, when compared to participants without dementia, after adjusting for demographic, health, and economic factors. Economic and social factors that may influence care demands (more caregivers, income-to-poverty ratio, and additional insurance) increased likelihood for cessation for those with dementia.

CONCLUSIONS

Older adults with (vs. without) dementia are more likely to cease hearing aid use over time, most notably during the first year after adoption. Strategies to support hearing ability, such as self-management or care partner education, may improve communication for those living with co-occurring hearing loss and dementia.

Biological factors influencing depression in later life: role of aging processes and treatment implications

Late-life depression occurring in older adults is common, recurrent, and malignant. It is characterized by affective symptoms, but also cognitive decline, medical comorbidity, and physical disability. This behavioral and cognitive presentation results from altered function of discrete functional brain networks and circuits. A wide range of factors across the lifespan contributes to fragility and vulnerability of those networks to dysfunction. In many cases, these factors occur earlier in life and contribute to adolescent or earlier adulthood depressive episodes, where the onset was related to adverse childhood events, maladaptive personality traits, reproductive events, or other factors. Other individuals exhibit a later-life onset characterized by medical comorbidity, pro-inflammatory processes, cerebrovascular disease, or developing neurodegenerative processes. These later-life processes may not only lead to vulnerability to the affective symptoms, but also contribute to the comorbid cognitive and physical symptoms. Importantly, repeated depressive episodes themselves may accelerate the aging process by shifting allostatic processes to dysfunctional states and increasing allostatic load through the hypothalamic-pituitary-adrenal axis and inflammatory processes. Over time, this may accelerate the path of biological aging, leading to greater brain atrophy, cognitive decline, and the development of physical decline and frailty. It is unclear whether successful treatment of depression and avoidance of recurrent episodes would shift biological aging processes back towards a more normative trajectory. However, current antidepressant treatments exhibit good efficacy for older adults, including pharmacotherapy, neuromodulation, and psychotherapy, with recent work in these areas providing new guidance on optimal treatment approaches. Moreover, there is a host of nonpharmacological treatment approaches being examined that take advantage of resiliency factors and decrease vulnerability to depression. Thus, while late-life depression is a recurrent yet highly heterogeneous disorder, better phenotypic characterization provides opportunities to better utilize a range of nonspecific and targeted interventions that can promote recovery, resilience, and maintenance of remission.

Listening with an Ageing Brain - a Cognitive Challenge

Hearing impairment has been recently identified as a major modifiable risk factor for cognitive decline in later life and has been becoming of increasing scientific interest. Sensory and cognitive decline are connected by complex bottom-up and top-down processes, a sharp distinction between sensation, perception, and cognition is impossible. This review provides a comprehensive overview on the effects of healthy and pathological aging on auditory as well as cognitive functioning on speech perception and comprehension, as well as specific auditory deficits in the 2 most common neurodegenerative diseases in old age: Alzheimer disease and Parkinson syndrome. Hypotheses linking hearing loss to cognitive decline are discussed, and current knowledge on the effect of hearing rehabilitation on cognitive functioning is presented. This article provides an overview of the complex relationship between hearing and cognition in old age.

Plasticity After Hearing Rehabilitation in the Aging Brain

Age-related hearing loss, presbycusis, is an unavoidable sensory degradation, often associated with the progressive decline of cognitive and social functions, and dementia. It is generally considered a natural consequence of the inner-ear deterioration. However, presbycusis arguably conflates a wide array of peripheral and central impairments. Although hearing rehabilitation maintains the integrity and activity of auditory networks and can prevent or revert maladaptive plasticity, the extent of such neural plastic changes in the aging brain is poorly appreciated. By reanalyzing a large-scale dataset of more than 2200 cochlear implant users (CI) and assessing the improvement in speech perception from 6 to 24 months of use, we show that, although rehabilitation improves speech understanding on average, age at implantation only minimally affects speech scores at 6 months but has a pejorative effect at 24 months post implantation. Furthermore, older subjects (>67 years old) were significantly more likely to degrade their performances after 2 years of CI use than the younger patients for each year increase in age. Secondary analysis reveals three possible plasticity trajectories after auditory rehabilitation to account for these disparities: Awakening, reversal of deafness-specific changes; Counteracting, stabilization of additional cognitive impairments; or Decline, independent pejorative processes that hearing rehabilitation cannot prevent. The role of complementary behavioral interventions needs to be considered to potentiate the (re)activation of auditory brain networks.

Linking Affective and Hearing Sciences-Affective Audiology

A growing number of health-related sciences, including audiology, have increasingly recognized the importance of affective phenomena. However, in audiology, affective phenomena are mostly studied as a consequence of hearing status. This review first addresses anatomical and functional bidirectional connections between auditory and affective systems that support a reciprocal affect-hearing relationship. We then postulate, by focusing on four practical examples (hearing public campaigns, hearing intervention uptake, thorough hearing evaluation, and tinnitus), that some important challenges in audiology are likely affect-related and that potential solutions could be developed by inspiration from affective science advances. We continue by introducing useful resources from affective science that could help audiology professionals learn about the wide range of affective constructs and integrate them into hearing research and clinical practice in structured and applicable ways. Six important considerations for good quality affective audiology research are summarized. We conclude that it is worthwhile and feasible to explore the explanatory power of emotions, feelings, motivations, attitudes, moods, and other affective processes in depth when trying to understand and predict how people with hearing difficulties perceive, react, and adapt to their environment.

A Scoping Review and Field Guide of Theoretical Approaches and Recommendations to Studying the Decision to Adopt Hearing Aids

OBJECTIVES

Given the low rates of hearing aid adoption among individuals with hearing loss, it is imperative to better understand the decision-making processes leading to greater hearing aid uptake. A careful analysis of the existing literature on theoretical approaches to studying these processes is needed to help researchers frame hypotheses and methodology in studies on audiology. Therefore, we conducted a scoping review with two aims. First, we examine theories that have been used to study research on hearing aid adoption. Second, we propose additional theories from the behavioral sciences that have not yet been used to examine hearing aid uptake but that can inform future research.

DESIGN

We identified peer-reviewed publications whose research was driven by one or more theoretical approaches by searching through PubMed, ProQuest PsycINFO, CINHAL Plus, Web of Science, Scopus, and OVID Medline/Embase/PsycINFO. The publications were examined by two researchers for eligibility.

RESULTS

Twenty-three papers were included in the analysis. The most common theoretical approaches studied include the Health Belief Model, the Transtheoretical Model of Behavior Change, Self-Determination Theory, and the COM-B Model. Seven other theoretical frameworks based on cognitive psychology and behavioral economics have also appeared in the literature. In addition, we propose considering nudge theory, framing effect, prospect theory, social learning theory, social identity theory, dual process theories, and affective-based theories of decision making when studying hearing aid adoption.

CONCLUSIONS

We conclude that, although a number of theories have been considered in research on hearing aid uptake, there are considerable methodological limitations to their use. Furthermore, the field can benefit greatly from the inclusion of novel theoretical approaches drawn from outside of audiology.

Hearing Aid Use Time Is Causally Influenced by Psychological Parameters in Mildly Distressed Patients with Chronic Tinnitus and Mild-to-Moderate Hearing Loss

Background: Hearing aids (HAs) can improve tinnitus-related distress (TRD) and speech-comprehension (SC) in silence or at 55 dB level of noise-interference (SC_55 dB) in patients with chronic tinnitus and mild-to-moderate hearing loss. However, the role of HA use time in relation to psychological, audiological, or self-reported tinnitus characteristics is an under-investigated area. Methods: We examine 177 gender-stratified patients before (t1) and after an intervention comprising binaural DSLchild algorithm-based HA fitting and auditory training (t2) and at a 70-day follow up [t3]. HA use time was retrospectively retrieved (at t2) for the pre-post- and (at t3) post-follow up periods. General linear models investigated HA use time in relation to (1) general audiological, (2) tinnitus-related audiological, (3) tinnitus-related self-report, and (4) distress-related self-report indices before and after treatment, where applicable. Receiver operator characteristic analyses identified optimal HA use time for hereby-mediated treatment changes. Results: At t1 and t2, psychological, but not audiological indices causally influenced prospective HA use time—except for SC_55 dB at t1, which, however, correlated with patients’ anxiety, depressivity, and psychological distress levels. Correlations did not differ between patient subgroups defined by categorical tinnitus-related audiological or self-report indices. HA use time partly mediated treatment-related improvement in TRD, but not SC. Optimal use amounted to 9.5–10.5 h/day. Conclusions: An awareness of psychological influences may help clinicians facilitate HA use and, thereby, TRD improvement with hearing amplification.

DSLchild-Algorithm-Based Hearing Aid Fitting Can Improve Speech Comprehension in Mildly Distressed Patients with Chronic Tinnitus and Mild-to-Moderate Hearing Loss

Background: Patients with chronic tinnitus and mild-to-moderate hearing loss (HL) can experience difficulties with speech comprehension (SC). The present study investigated SC benefits of a two-component hearing therapy. Methods: One-hundred-seventy-seven gender-stratified patients underwent binaural DSL_child-algorithm-based hearing aid (HA) fitting and conducted auditory training exercises. SC was measured at four timepoints under three noise interference conditions each (0, 55, and 65 dB): after screening (t₀; without HAs), HA- fitting (t₁), additional auditory training (t₂), and at 70-day follow-up (t₃). Repeated-measure analyses of covariance investigated the effects of HAs (t₀–t₁), auditory training (t₁–t₂), and the stability of the combined effect (t₂–t₃) on SC per noise interference level and HL subgroup. Correlational analyses examined associations between SC, age, and psychological indices. Results: Patients showed mildly elevated tinnitus-related distress, which was negatively associated with SC in patients with mild but not moderate HL. At 0 dB, the intervention lastingly improved SC for patients with mild and moderate HL; at 55 dB, for patients with mild HL only. These effects were mainly driven by HAs. Conclusions: The here-investigated treatment demonstrates some SC-benefit under conditions of no or little noise interference. The auditory training component warrants further investigation regarding non-audiological treatment outcomes.

Considering hearing loss as a modifiable risk factor for dementia

INTRODUCTION

Accumulating evidence links hearing loss to impaired cognitive performance and increased risk for dementia. Hearing loss can lead to deafferentation-induced atrophy of frontotemporal brain regions and dysregulation of cognitive control networks from increased listening effort. Hearing loss is also associated with reduced social engagement, loneliness, and depression, which are independently associated with poor cognitive function.

AREAS COVERED

We summarize the evidence and postulated mechanisms linking hearing loss to dementia in older adults and synthesize the available literature demonstrating beneficial effects of hearing remediation on brain structure and function.

EXPERT OPINION

: Further research is needed to evaluate whether treatment of hearing loss may reduce risk of cognitive decline and improve neural consequences of hearing loss. Studies may investigate the pathologic mechanisms linking these late-life disorders and identify individuals vulnerable to dementia, and future clinical trials may evaluate whether hearing treatment may reduce the risk for dementia.

A precision medicine tool to understand who responds best to hearing aids in late-life depression

OBJECTIVES

Accumulating evidence suggests that hearing loss (HL) treatment may benefit depressive symptoms among older adults with Major Depressive Disorder (MDD), but the specific individual characteristics of those who stand to improve most are unknown.

METHODS

N = 37 patients ≥60 years with HL and MDD received either active or sham hearing aids in this 12-week double-blind randomized controlled trial. A combined moderator approach was utilized in the analysis in order to examine multiple different pretreatment individual characteristics to determine the specific qualities that predicted the best depressive symptom response to hearing aids. Pretreatment characteristics included: Hearing Handicap Inventory for the Elderly (HHIE-S), pure tone average (PTA), speech reception threshold (SRT), Short Physical Performance Battery (SPPB), cognition (Repeatable Battery for the Assessment of Neuropsychological Status).

RESULTS

The analysis revealed a combined moderator, predicting greater improvement with active versus sham hearing aids, that had a larger effect size than any individual moderator (combined effect size [ES] = 0.49 [95% CI: 0.36, 0.76]). Individuals with worse hearing-related disability (HHIE-S: individual ES = -0.16), speech recognition (SRT: individual ES = -0.14), physical performance (SPPB: individual ES = 0.41), and language functioning (individual ES = 0.19) but with relatively less severe audiometric thresholds (PTA: individual ES = 0.17) experienced greater depressive symptom improvement with active hearing aids.

CONCLUSIONS

Older adults with relatively worse HL-related, physical, and cognitive functioning may stand to benefit most from hearing aids. Given the large number of older adults experiencing HL and MDD, a non-invasive and scalable means of targeting those most likely to respond to interventions would be valuable.

Hearing Rehabilitative Treatment for Older Adults With Comorbid Hearing Loss and Depression: Effects on Depressive Symptoms and Executive Function

OBJECTIVES

Recent research has revealed important neural and psychiatric consequences of hearing loss (HL) in older adults. This pilot study examined the neural effects of HL and the impact of hearing aids on neuropsychiatric outcomes in major depressive disorder (MDD).

DESIGN

Twelve-week, double-blind, randomized controlled trial.

PARTICIPANTS/INTERVENTION

N = 25 (≥60 years) with MDD and moderate-profound HL were randomized to receive hearing aids (100% gain targets) or sham hearing aids (flat 30 dB HL) in addition to psychiatric treatment-as-usual.

MEASUREMENTS

Depressive symptoms (Hamilton Rating Scale for Depression [HRSD]), executive functioning (NIH Toolbox Flanker), integrity of auditory brain areas (structural MRI, diffusion tensor imaging).

RESULTS

At baseline, worse speech discrimination was associated with auditory cortical thinning (Left anterior transverse temporal gyrus: r = 0.755, p = 0.012) and lower integrity of the superior longitudinal fasciculus (FA: Left r = 0.772, p = 0.025, Right r = 0.782, p = 0.022). After 12-weeks, hearing aids were effective at improving hearing functioning (Hearing Handicap for the Elderly: active -12.47 versus sham -4.19, t = -2.64, df = 18, p = 0.016) and immediate memory (active +14.9 versus sham +5.7, t = 2.28, df = 16, p = 0.037). Moderate improvement was observed for hearing aids on executive functioning but did not reach statistical significance (Flanker: active +4.8 versus sham -2.4, t = 1.95, df = 15, p = 0.071). No significant effect on depression was found (HRSD: active -5.50 versus sham -7.32, t = 0.75, df = 19, p = 0.46).

CONCLUSIONS

HL can affect brain regions important for auditory and cognitive processing, and hearing remediation may have beneficial effects on executive functioning in MDD. Future studies may evaluate whether impairment in cognitive control consequent to HL may be an important risk mechanism for MDD.

Hearing Loss and Cognition: What We Know and Where We Need to Go

Although a causal association remains to be determined, epidemiologic evidence suggests an association between hearing loss and increased risk of dementia. If we determine the association is causal, opportunity for targeted intervention for hearing loss may play a fundamental role in dementia prevention. In this discussion, we summarize current research on the association between hearing loss and dementia and review potential casual mechanisms behind the association (e.g., sensory-deprivation hypothesis, information-degradation hypothesis, common cause). We emphasize key areas of research which might best inform our investigation of this potential casual association. These selected research priorities include examination of the causal mechanism, measurement of co-existing hearing loss and cognitive impairment and determination of any bias in testing, potential for managing hearing loss for prevention of dementia and cognitive decline, or the potential to reduce dementia-related symptoms through the management of hearing loss. Addressing these research gaps and how results are then translated for clinical use may prove paramount for dementia prevention, management, and overall health of older adults.

Pure Tone Audiometry and Hearing Loss in Alzheimer's Disease: A Meta-Analysis

An association between age-related hearing loss (ARHL) and Alzheimer's Disease (AD) has been widely reported. However, the nature of this relationship remains poorly understood. Quantification of hearing loss as it relates to AD is imperative for the creation of reliable, hearing-related biomarkers for earlier diagnosis and development of ARHL treatments that may slow the progression of AD. Previous studies that have measured the association between peripheral hearing function and AD have yielded mixed results. Most of these studies have been small and underpowered to reveal an association. Therefore, in the current report, we sought to estimate the degree to which AD patients have impaired hearing by performing a meta-analysis to increase statistical power. We reviewed 248 published studies that quantified peripheral hearing function using pure-tone audiometry for subjects with AD. Six studies, with a combined total of 171 subjects with AD compared to 222 age-matched controls, met inclusion criteria. We found a statistically significant increase in hearing threshold as measured by pure tone audiometry for subjects with AD compared to controls. For a three-frequency pure tone average calculated for air conduction thresholds at 500-1,000-2,000 Hz (0.5-2 kHz PTA), an increase of 2.3 decibel hearing level (dB HL) was found in subjects with AD compared to controls (p = 0.001). Likewise, for a four-frequency pure tone average calculated at 500-1,000-2,000-4,000 (0.5-4 kHz PTA), an increase of 4.5 dB HL was measured (p = 0.002), and this increase was significantly greater than that seen for 0.5-2 kHz PTA. There was no difference in the average age of the control and AD subjects. These data confirm the presence of poorer hearing ability in AD subjects, provided a quantitative estimate of the magnitude of hearing loss, and suggest that the magnitude of the effect is greater at higher sound frequencies. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier: CRD42021288280.

A framework of social determinants of health for delirium tailored to older adults

Delirium is a debilitating medical condition that disproportionately affects hospitalized older adults and is associated with adverse health outcomes, increased mortality, and high medical costs. Efforts to understand delirium risk in hospitalized older adults have focused on examining medical comorbidities, pre-existing cognitive deficits, and other clinical and demographic factors present in the period proximate to the hospitalization. The contribution of social determinants of health (SDOH), including social circumstances, environmental characteristics, and early-life exposures, referred as the social exposome, to delirium risk is poorly understood. Increased knowledge about the influence of SDOH will offer a more comprehensive understanding of factors that may increase vulnerability to delirium and poor outcomes. Clinically, these efforts can guide the development and implementation of holistic preventive strategies to improve clinical outcomes. We propose a SDOH framework for delirium adapted for older adults. We provide the definition, description, and rationale for the domains and variables in our proposed model.

The effect of hearing aids on cognitive function: A systematic review

RATIONALE

Dementia currently affects 50 million people globally with this expected to triple by 2050. Even though hearing loss is associated with cognitive decline, the underlying mechanisms are not fully understood. Considering hearing loss is the largest modifiable risk factor for developing dementia, it is essential to study the effect of hearing aids on cognitive function.

OBJECTIVE

To systematically review the existing literature to examine the evidence for using hearing aids intervention as a treatment for deteriorating cognitive function.

DESIGN

A search of PubMed, Cochrane Library, Embase and grey literature was conducted revealing 3060 unique records between 1990-2020. Two reviewers independently selected longitudinal studies observing the effects of hearing aids on cognitive function in persons without dementia at onset of the study. Due to the heterogeneity of the data, a meta-analysis could not be performed. Outcomes are described in a summary of findings table and portrayed diagrammatically.

RESULTS

We identified 17 unique studies, spanning 30 years of research and 3526 participants. The included studies made use of 50 different cognitive function tests. These tests were grouped into separate cognitive domains according to the DSM-V classification for further analysis. The most beneficial impact of hearing aids seems to be in the cognitive domain of executive function, with six studies showing improvement, two studies being inconclusive and three studies not demonstrating a significant effect. Three of five studies demonstrated significant improvement when screening for brief mental status. The least beneficial impact is seen in domain of complex attention, with eight studies showing no significant effects, compared with one demonstrating improvement with intervention.

CONCLUSIONS

Based on this systematic review, we conclude that there is controversy about the effects of hearing aids on cognition. Additional research through randomized clinical trials with standardized cognitive assessment and longer follow-up is warranted to further elucidate this relationship.

Hearing Impairment and Cognition in an Aging World

With the increasing number of older adults around the world, the overall number of dementia cases is expected to rise dramatically in the next 40 years. In 2020, nearly 6 million individuals in the USA were living with Alzheimer's disease, the most common type of dementia, with anticipated growth to nearly 14 million by year 2050. This increasing prevalence, coupled with high societal burden, makes prevention and intervention of dementia a medical and public health priority. As clinicians and researchers, we will continue to see more individuals with hearing loss with other comorbidities including dementia. Epidemiologic evidence suggests an association between hearing loss and increased risk of dementia, presenting opportunity for targeted intervention for hearing loss to play a fundamental role in dementia prevention. In this discussion, we summarize current research on the association between hearing loss and dementia and review potential casual mechanisms behind the association (e.g., sensory-deprivation hypothesis, information-degradation hypothesis, common cause). We emphasize key areas of research which might best inform our investigation of this potential casual association. These selected research priorities include examination of the causal mechanism, measurement of co-existing hearing loss and cognitive impairment, and potential of aural rehabilitation. Addressing these research gaps and how results are then translated for clinical use is paramount for dementia prevention and overall health of older adults.

Neural circuits and behavioral pathways linking hearing loss to affective dysregulation in older adults

Substantial evidence now links age-related hearing loss to incident major depressive disorder in older adults. However, research examining the neural circuits and behavioral mechanisms by which age-related hearing loss leads to depression is at an early phase. It is known that hearing loss has adverse structural and functional brain consequences, is associated with reduced social engagement and loneliness, and often results in tinnitus, which can independently affect cognitive control and emotion processing circuits. While pathways leading from these sequelae of hearing loss to affective dysregulation and depression are intuitive to hypothesize, few studies have yet been designed to provide conclusive evidence for specific pathophysiological mechanisms. Here we review the neurobiological and behavioral consequences of age-related hearing loss, present a model linking them to increased risk for major depressive disorder and suggest how future studies may facilitate the development of rationally designed therapeutic interventions for older adults with impaired hearing to reduce risk for depression and/or ameliorate depressive symptoms.