Cognitive reserve regulates the association between hearing difficulties and incident cognitive impairment evidence from a longitudinal study in China

How to Break Stubborn Association Between Hearing Loss and Cognitive Impairment: A Systematic Review and Meta-Analysis of Moderators and Mediators

BackgroundHearing loss has been related to impaired cognition among older adults. The cost effectiveness of existing hearing support tools is controversial. Other potential modifying strategies that could effectively intervene in this prevalent and far-reaching association between hearing loss and cognitive decline remain unclear. This study aimed to narratively and quantitatively synthesize the mediators and moderators involved in the link between hearing loss and cognitive impairment from a psycho-social and physical point of view.MethodWe searched 6 databases for articles exploring mediating or moderating associations of hearing loss-cognition association from inception to March, 2024. Data were synthesized narratively and quantitatively by meta-analytic approaches.ResultsThe search yielded 63 included studies. Social (social engagement, social support, age, sex, ethnicity, cognitive reserve)-psycho (depression, anxiety, loneliness, resilience)-physical (cardiovascular diseases and risk factors, perceived health, disability, APOE carrier, vision impairment, gait speed) variables mediated or moderated the relationship between hearing loss and cognitive impairment to varying degrees. Subgroup analyses identified susceptible populations at greater risk for cognitive decline, including women, younger elders with hearing loss, and older adults with dual sensory loss.ConclusionCombined interventions targeting these modifiable variables across psycho-social and physical dimensions may be more cost-effective for intervening in the ensemble of hearing loss-cognitive impairment in older adults.

Late Life Cognitive Function Trajectory Among the Chinese Oldest-Old Population-A Machine Learning Approach

Informed by the biopsychosocial framework, our study uses the Chinese Longitudinal Healthy Longevity Survey (CLHLS) dataset to examine cognitive function trajectories among the oldest-old (80+). Employing K-means clustering, we identified two latent groups: High Stability (HS) and Low Stability (LS). The HS group maintained satisfactory cognitive function, while the LS group exhibited consistently low function. Lasso regression revealed predictive factors, including socioeconomic status, biological conditions, mental health, lifestyle, psychological, and behavioral factors. This data-driven approach sheds light on cognitive aging patterns and informs policies for healthy aging. Our study pioneers non-parametric machine learning methods in this context.

The benefits of physical exercise on older adults' cognitive function: A cohort study exploring potential mechanisms

BACKGROUND

Despite existing studies showing that physical exercise improves cognitive function in older adults either concurrently or in a delayed manner, studies examining these associations simultaneously are rare. Additionally, the underlying mechanisms in these associations remain incompletely understood.

OBJECTIVE

This study explores the concurrent and delayed (two years later) associations between physical exercise and older adults' cognitive function. This study also investigates the mediating roles of three negative physical, psychological, and social resources: limitations in daily abilities, depressive mood, and isolation from friends, as well as the moderating roles of cognitive reserve on these associations.

DESIGN

A cohort sample of 6646 Chinese older adults (Mean age = 69.28, SD = 7.03) is obtained from the 2016 and 2018 waves of the China Longitudinal Aging Social Survey. Regression analysis was employed to test the concurrent and delayed associations between physical exercise and cognitive function. The bootstrap method was utilized to examine the mediating roles of limitations in daily activities, depression mood, and isolation from friends. Interaction terms were generated to investigate the moderating roles of cognitive reserve.

RESULTS

Physical exercise presents concurrent and delayed positive associations with cognitive function. Limitations in daily activities, depressive mood and isolation from friends mediate the above associations. Moreover, cognitive reserve plays a significant role in buffering the concurrent and delayed negative links between depressive mood, isolation from friends, and cognitive function, with larger negative relationships observed for older adults with lower rather than higher levels of cognitive reserve.

CONCLUSIONS

This study validates the concurrent and delayed benefits of physical exercise on older adults' cognitive function while elucidating the underlying mechanisms. These findings offer practical implications for health policies and intervention programs aimed at enhancing older adults' cognitive function.

Adult-onset hearing loss and incident cognitive impairment and dementia - A systematic review and meta-analysis of cohort studies

BACKGROUND

We comprehensively summarized the cohort evidence to date on adult-onset hearing loss as risk factor for incident cognitive impairment and dementia, and examined the evidence for dose-response, risk for various dementia subtypes, and other moderators. Previous meta-analyses were less comprehensive.

METHODS

We included cohort studies with participants without dementia and with hearing assessments at baseline, minimum 2 years follow-up and incident cognitive outcomes. We used random-effect models and subgroup and meta-regression on moderator analyses.

RESULTS

We identified fifty studies (N=1,548,754). Hearing loss (yes/no) was associated with incident dementia risk (HR=1.35 [95% CI = 1.26 - 1.45), mild cognitive impairment (MCI HR=1.29 [95% CI = 1.11 - 1.50]), cognitive decline not specified as MCI or dementia (HR=1.29 [95% CI = 1.17 - 1.42]), and Alzheimer's disease dementia (ADD, HR=1.56 [95% CI = 1.30 - 1.87]), but not with vascular dementia (HR, 1.30 [95% CI = 0.83 - 2.05]). Each 10-decibel worsening of hearing was associated with a 16% increase in dementia risk (95% CI = 1.07 - 1.27). The effect of hearing loss did not vary across potential moderators.

CONCLUSIONS

Cohort studies consistently support that adult-onset hearing loss increases the risk of incident cognitive decline, dementia, MCI, and ADD.

Estimating the impact of different types hearing loss on cognitive decline and the joint effect of hearing loss and depression on cognitive decline among older adults in China

BACKGROUND

Current research lacks examination of the relationship between different subtypes of hearing loss (HL) and cognitive decline (CD). Additionally, the co-effects of HL and depression on CD remain unexplored. This study aims to investigate the relationship between HL, various types of HL, and CD, as well as the combined impact of HL and depression on CD.

METHODS

Data from a total of 5218 older adults who participated in the most recent three waves of Chinese Longitudinal Healthy Longevity Survey (CLHLS) (2011-2012, 2014, and 2018) were included. HL was assessed through self-report and objective measures. CD was defined as a decrease in MMSE score of≥3 between any two survey periods for older adults. Cox proportional hazards model was applied to analyzed.

RESULTS

Among Chinese older adults, bilateral HL (HR = 1.202, 95%CI = 1.093-1.322, P < 0.001), onset of HL after the age of 40 (HR = 1.155, 95%CI = 1.056-1.264, P = 0.002), and chronic HL (HR = 1.143, 95%CI = 1.040-1.255, P = 0.005) posed a greater risk. HL (HR = 1.146, 95%CI = 1.048-1.254, P = 0.003) and depression (HR = 1.162, 95%CI = 1.038-1.301, P = 0.009) were independently or jointly associated with CD. Participants who were simultaneously exposed to both HL and depression experienced the highest risk of CD (HR = 1.314, 95%CI = 1.117-1.545, P = 0.001).

LIMITATIONS

Given the observational design, unidentified confounding variables may still be present, such as whether to wear a hearing aid.

CONCLUSION

This study emphasizes the high risk of specific types of HL for CD and the importance of implementing health interventions that address both physiological and psychological aspects to enhance cognitive function and prevent CD in older adults.

[Relationship Between Hearing Loss and Cognitive Function in Elderly Chinese People: A Study Based on Propensity Score Matching]

Objective

To explore the relationship between hearing loss and cognitive function in the elderly population through propensity score matching method.

Methods

We analyzed the data of 7605 participants aged 60 and above who were included in the 2018 China Health and Retirement Longitudinal Study (CHARLS). The non-substitutable 1∶1 nearest neighbor matching method without caliper value was used for propensity score matching and G-computation was used to estimate the average treatment effect (ATE) of hearing loss on all dimensions of cognitive function.

Results

Before matching, there were 3626 (47.68%) women, with 1409 (18.53%) of whom suffering from hearing loss and 3031 (39.86%) of whom suffering from cognitive impairment. After matching, 1409 subjects were included in the hearing loss group and 1409, in the normal hearing group, with both groups sharing similar distribution of basic demographic characteristics. The results for the average treatment effect of the population indicated that the cognitive function scores of the hearing loss group were lower than those of the normal hearing group, with the overall cognitive function being 0.593 points lower (95% confidence intervel [CI]: －0.916-－0.257, P<0.001), orientation being 0.183 points lower (95% CI: －0.302-－0.055, P=0.004), immediate memory being 0.150 points lower (95% CI: －0.218-－0.085, P<0.001), and language skills being 0.178 points lower (95% CI: －0.303-－0.058, P=0.006). The prevalence of cognitive impairment of the hearing loss group was 4.2% higher than that of the normal hearing group (95% CI: 0.007-0.077, P=0.020).

Conclusion

Hearing loss adversely affects the orientation, memory, and language skills of the elderly population and forms a potential risk factor for cognitive impairment in the elderly population.

The longitudinal relationship between hearing loss and cognitive decline in tonal language-speaking older adults in China

Introduction

Previous longitudinal studies indicate that hearing loss and cognitive impairment are associated in non-tonal language-speaking older adults. This study aimed to investigate whether there is a longitudinal association between hearing loss and cognitive decline in older adults who speak a tonal language.

Methods

Chinese-speaking older adults aged 60 years and above were recruited for baseline and 12 month follow-up measurements. All participants completed a pure tone audiometric hearing test, Hearing Impaired-Montreal Cognitive Assessment Test (HI-MoCA), and a Computerized Neuropsychological Test Battery (CANTAB). The De Jong Gierveld Loneliness Scale was used to measure loneliness, and the 21-item Depression Anxiety Stress Scale (DASS-21) was used to measure aspects of mental health. Associations between baseline hearing loss and various cognitive, mental and psychosocial measures were evaluated using logistic regression.

Results

A total of 71 (29.6%) of the participants had normal hearing, 70 (29.2%) had mild hearing loss, and 99 (41.2%) had moderate or severe hearing loss at baseline, based on mean hearing thresholds in the better ear. After adjusting for demographic and other factors, baseline moderate/severe audiometric hearing loss was associated with an increased risk of cognitive impairment at follow-up (OR: 2.20, 95% CI: 1.06, 4.50). When pure-tone average (PTA) was modeled continuously, an average difference of 0.24 in HI-MoCA scores for every 10 dB increase in BE4FA existed, and an average difference of 0.07 in the change of HI-MoCA scores in a 12 month period.

Discussion

The results revealed a significant longitudinal relationship between age-related hearing loss and cognitive decline in this cohort of tonal language-speaking older adults. Steps should also be taken to incorporate hearing assessment and cognitive screening in clinical protocols for older adults 60 years and above in both hearing and memory clinics.

Cognitive reserve in patients with mood disorders: Validation study of the Chinese version of the cognitive reserve assessment scale in health

BACKGROUND

Cognitive reserve (CR) is closely associated with cognitive and functional outcome, disease severity, progression and prognosis in psychiatric patients; however, it has not been extensively tested in mood disorders. This study examined the psychometric properties of the Cognitive Reserve Assessment Scale in Health (CRASH) in mood disorder patients.

METHODS

Altogether 166 subjects were recruited, 44 with major depressive disorder (MDD), 64 with bipolar disorder (BD), and 58 healthy controls. CR was assessed using the CRASH and the Cognitive Reserve Questionnaire (CRQ).

RESULTS

Internal consistency (Cronbach's alpha) was 0.779 for the CRASH. The Receiver Operating Characteristic (ROC) curve analysis revealed an area under the ROC curve (AUC) value of 0.73 (95 % CI: 0.647-0.809). The optimal cut-off score of 51 generated the best combination of sensitivity (0.78) and specificity (0.43) for discriminating between patients with mood disorders and healthy controls. The CRASH score was highly correlated with the CRQ score in both mood disorder patients (r_s = 0.586, P < 0.001) and healthy controls (r_s = 0.627, P < 0.001), indicating acceptable convergent validity for the CRASH. Within the mood disorder sample, the CRASH score was associated with functional outcomes (FAST: r_s = -0.243, P = 0.011).

CONCLUSIONS

The CRASH is a useful tool to measure CR in mood disorder with acceptable psychometric properties and could be used in both research and clinical practice.

Effect of hearing loss on cognitive function in patients with mild cognitive impairment: A prospective, randomized, and controlled study

Background

Hearing loss (HL) may increase the risk of cognitive decline in the elderly. However, the randomized controlled study on the effect of HL on cognitive function in mild cognitive impairment (MCI) is very limited.

Methods

From 1 November 2020 to 30 March 2022, 1,987 individuals aged 55–65 years were randomly divided into the MCI with hearing impairment (MCI-HI), MCI without HI (MCI-nHI), and no MCI (nMCI) groups by stratified sampling, with 30 participants in each group. The Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the pure tone audiometry (PTA), and the auditory brainstem response (ABR) were measured at baseline and a follow-up 12 months later. The trial protocol was registered with ClinicalTrials.gov with the registration number NCT05336942.

Results

Among the 90 participants, the average age was 60.41 ± 6.48 years. In the MCI-HI group at baseline, the PTA score of both the ears was negatively correlated with the naming and memory score (p < 0.05), and the PTA score of both the ears was negatively correlated with the MoCA and abstraction score at the 12-month follow-up (p < 0.05). However, there were no significant differences among the PTA, the ABR, the MMSE, and the MoCA scores in the MCI-nHI and nMCI groups (p > 0.05). Regression analysis showed that the PTA score of the right ear at baseline was an important factor associated with the MoCA, visuospatial/executive, naming, and abstraction scores at the 12-month follow-up (β = −0.776 to −0.422, p < 0.05).

Conclusion

HL was significantly negatively associated with cognitive function only in patients with MCI with hearing impairment (HI), and the PTA of the right ear may be a predictor of cognitive decline after 1 year in patients with MCI with HI. This information may help primary healthcare clinicians to prevent MCI by screening and intervening in care for elderly patients with HL.

Cognition and Cognitive Reserve in Cochlear Implant Recipients

At present, dementia is a hot topic. Hearing loss is considered to be a modifiable risk factor for cognitive decline. The underlying mechanism remains unclear and might be mediated by socioeconomic and psychosocial factors. Cochlear implantation has been shown not only to restore auditory abilities, but also to decrease mental distress and to improve cognitive functions in people with severe hearing impairment. However, the promising results need to be confirmed. In a prospective single-center study, we tested the neurocognitive abilities of a large group of 71 subjects with bilateral severe hearing impairment with a mean age of 66.03 (SD = 9.15) preoperatively and 6, 12, and 24 months after cochlear implantation using a comprehensive non-auditory computer-based test battery, and we also assessed the cognitive reserve (CR) [Cognitive Reserve Index (CRI)], health-related quality of life (QoL) (Nijmegen Cochlear Implant Questionnaire), and depression (Geriatric Depression Scale-15). Cognitive functions significantly increased after 6 months in attention (p = 0.00004), working memory (operation span task; p = 0.002), and inhibition (p = 0.0002); and after 12 months in recall (p = 0.003) and verbal fluency (p = 0.0048), and remained stable up to 24 months (p ≥ 0.06). The CR positively correlated with cognitive functions pre- and post-operatively (both p < 0.005), but postoperative improvement in cognition was better in subjects with poor CR (p = 0.003). Depression had only a slight influence on one subtest. No correlation was found among cognitive skills, quality of life, and speech perception (each p ≥ 0.05). Cochlear implantation creates an enriched environment stimulating the plasticity of the brain with a global positive impact on neurocognitive functions, especially in subjects with poor preoperative cognitive performance and low cognitive reserve.

Modifiable lifestyle factors and cognitive reserve: A systematic review of current evidence

This systematic review aims to summarize cognitive reserve (CR) evaluation approaches and to examine the role of seven selected modifiable lifestyle factors (diet, smoking, alcohol consumption, physical activity, cognitive leisure activity, sleep, and meditation) in mitigating the impacts of age- or disease-related brain changes on cognition. Eighteen population-based English empirical studies were included. We summarize the study designs and identify three CR models that were broadly used in these studies, including a residual model assessing lifestyle factors in relation to unexplained variance in cognition after accounting for brain markers, a moderation model testing whether lifestyle factors moderate the relationship between brain status and cognition, and a controlling model examining the associations between lifestyle factors and cognition when controlling for brain measures. We also present the findings for the impact of each lifestyle factor. No studies examined diet, sleep, or meditation, and only two studies focused on smoking and alcohol consumption each. Overall, the studies suggest lifestyle activity factors (physical and cognitive leisure activities) may contribute to CR and attenuate the damaging impact of brain changes on cognition. Standardized measurements of lifestyle factors and CR are needed, and mechanisms underlying CR need to be further addressed as well.

Association of Hearing Acuity and Cognitive Function Among a Low-Income Elderly Population in Rural China: A Population-Based Cross-Sectional Study

Hearing loss is a modifiable risk factor for dementia and cognitive decline. However, the association between cognition and hearing acuity at different frequencies is unknown. We aimed to assess the relationships between hearing acuity at different frequencies with global cognitive function and five domains of cognition among a low-income elderly population in northern rural China. A population-based cross-sectional study was conducted to collect basic information from elderly residents aged 60 years and older in rural areas of Tianjin, China from April 2012 to November 2013. Pure tone averages (PTAs) at different frequencies in the ear with better hearing and Mini-Mental State Examination (MMSE) scores were measured, and the relationships between these variables were assessed. A total of 737 residents aged 60 years or more were enrolled in this study, and the prevalence of hearing impairment was 60.7%. After adjusting for sex, age, education, income, smoking, drinking, systolic blood pressure (SBP), total cholesterol (TC), and low-density lipoprotein cholesterol level (LDL-C), MMSE score and immediate recall score were negatively associated with overall PTA (OPTA) at four frequencies (0.5, 1, 2, and 4 kHz), PTA at low frequencies (LPTA; 0.5, 1, and 2 kHz), and PTA at high frequencies (HPTA; 3, 4, and 8 kHz) in the ear with better hearing. Moreover, orientation score was negatively associated with OPTA and LPTA, and the attention and calculation scores were negatively associated with OPTA and HPTA. Each 10-dB increase in OPTA was associated with a MMSE score decrease of 0.464. Each 10-dB increase in LPTA or HPTA was associated with a MMSE score decrease of 0.441 (95% CI: −0.795, −0.086) and 0.351 (95% CI: −0.592, −0.110), respectively. The present study demonstrated significant but weak relationships between OPTA, LPTA, and HPTA with global cognitive function, as defined using MMSE scores; these relationships were independent of age, education, lifestyle factors, and laboratory test values. These results indicated that hearing was associated with cognitive decline among older individuals, who should be screened routinely to identify risk for cognitive decline.

Self-reported hearing difficulty increases 3-year risk of incident cognitive impairment: The role of leisure activities and psychological resilience

OBJECTIVE

Although hearing difficulty is associated with cognitive impairment, little is known about the potential mechanisms involved. This study assessed the mediating effects of leisure activities and psychological resilience on the association between hearing difficulty and cognitive impairment.

METHODS

Two waves of Chinese Longitudinal Healthy Longevity Survey (2011-2014) were used in the current analysis. Hearing difficulty, leisure activities and psychological resilience were measured at baseline. Cognitive function was assessed using the Chinese version of the Mini-Mental State Examination. The data were analyzed using generalized structural equation modeling with adjustment for confounding factors.

RESULTS

Of the 4267 participants at baseline, 33.5% (1430) reported hearing difficulty. The incidence of cognitive impairment was 15.3% (651) during the 3-year follow-up. Hearing difficulty increased the risk of cognitive impairment (odds ratio [OR] = 1.59, 95% confidence intervals [CI]: 1.26-1.92). Leisure activities and psychological resilience partly mediated the association between hearing difficulty and cognitive impairment. Hearing difficulty was negatively related to leisure activities (β = -0.23, 95% CI: -0.41 to -0.05) and psychological resilience (β = -0.34, 95% CI: -0.57 to -0.11). Furthermore, leisure activities (OR = 0.92, 95% CI: 0.89-0.96) and psychological resilience (OR = 0.95, 95% CI: 0.93-0.98) would significantly decrease the risk of cognitive impairment.

CONCLUSIONS

Hearing difficulty was associated with the incidence of cognitive impairment in older adults. Leisure activities and psychological resilience mediated the relationship. Participation in leisure activity and promoting psychological resilience may be candidate interventions in preventing cognitive impairment among the individuals with hearing difficulty.

Leisure activities and psychological wellbeing reduce the risk of cognitive impairment among older adults with hearing difficulty: A longitudinal study in China

OBJECTIVES

. We used longitudinal cohort data to examine the effect of leisure activities and psychological wellbeing on the risk of cognitive impairment among Chinese older adults with hearing difficulty (HD).

STUDY DESIGN

. This prospective cohort study included 10,341 cognitively normal individuals aged 65 years or more at baseline from the Chinese Longitudinal Healthy Longevity survey (from 2002 to 2011).

MAIN OUTCOME MEASURES

. Hearing difficulty, leisure activities and psychological wellbeing were measured at baseline. Cognitive function was assessed using the Chinese version of the Mini-Mental State Examination (MMSE). Cognitive impairment was defined as an MMSE score of less than 18 points.

RESULTS

. During a median follow-up of 5.6 years (59,869 person-years), 2,614 participants developed cognitive impairment. Cox proportional hazards models showed that the multi-adjusted hazard ratio (HR, 95% confidence interval) of cognitive impairment was 1.42 (1.28-1.58) for HD. Participants with a healthy lifestyle had a lower risk of cognitive impairment (HR = 0.77, 95% CI 0.69-0.85). Furthermore, participants with HD and a healthy lifestyle (HR = 1.67, 95% CI 1.27-2.18) had a lower HR of cognitive impairment than those with HD and an unhealthy lifestyle (HR = 1.86, 95% CI 1.61-2.14). A healthy lifestyle also delayed the onset of cognitive impairment by 0.50 years in people with HD.

CONCLUSIONS

. HD was associated with an increased risk of cognitive impairment, but a healthy lifestyle may decrease the risk of cognitive impairment related to HD and delay the onset of cognitive impairment.