Impact of sensory impairments on dementia incidence and symptoms among Japanese older adults

The Associations of Sensory Impairment With 10-Year Risk of Dementia and Alzheimer's Disease: The Health and Retirement Study, 2010-2020

BACKGROUND

Studies have examined the association between dual sensory impairment and late-life cognitive outcomes in the U.S with inconsistent findings.

OBJECTIVE

To examine the associations between sensory impairment and 10-year risk of dementia or Alzheimer's disease among U.S. adults aged ≥ 50.

METHODS

A prospective cohort study based on the Health and Retirement Study from 2010 to 2020. Individuals aged ≥ 50 years without self-reported dementia and Alzheimer's disease in 2010 were included in the analysis. Self-reported visual and hearing impairments were measures in 2010. Main failure events included self-reported incident dementia and Alzheimer's disease over a 10-year follow-up period. Participants were categorized as having no visual or hearing impairment, visual impairment only, hearing impairment only, and dual sensory impairment. Fine-Gray competing risk regression model was applied to estimate the associations of sensory impairment with incident dementia and Alzheimer's disease, adjusted for demographic characteristics, health behaviors, and health conditions at baseline.

RESULTS

Of 20,248 identified individuals, 14.6% had visual impairment only, 11.2% had hearing impairment only, and 9.1% had dual impairment at baseline. After adjusting for all covariates, dual sensory impairment was associated with higher risk of dementia (HR = 1.46, 95% CI: 1.23-1.73) and Alzheimer's disease (HR = 1.35, 95% CI: 1.03-1.76). Visual impairment only was also associated with incident dementia and Alzheimer's disease among individuals <65 years.

CONCLUSION

Older adults in the U.S. with visual and hearing impairments simultaneously had a particularly greater risk of dementia and Alzheimer's disease, indicating the needs of targeted screening for timely treatment and further prevention of dementia and Alzheimer's disease.

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.

The relationship between self-reported sensory decline and cognitive frailty in older persons

This study aimed to explore the relationship between self-reported sensory decline, including poor hearing and vision, and cognitive frailty in older persons. This cross-sectional study analyzed data from the 2020 National Survey of Living Conditions and Welfare Needs of Older Koreans. Binomial logistic regression analysis was performed to analyze the relationship between self-reported sensory decline and cognitive frailty. Of 9,692 participants, 39.8 % experienced sensory decline. The prevalence of cognitive frailty was 15.7 % among participants with poor hearing, 6.9 % among those with poor vision, and 17.9 % among those with combined poor hearing and vision. In our model, adjusted for sociodemographic and health-related variables, the cognitive frailty was significantly associated with poor hearing alone and combined poor hearing and vision. The findings suggest that healthcare professionals should prioritize their attention to the risk of cognitive frailty in older adults experiencing poor hearing alone and combined with poor vision.

A Prospective Association Between Sensory Impairment and Cognitive Performance Among Older Community-Dwelling Adults: The Role of Depressive Symptoms

We examined whether vision impairment (VI) and hearing impairment (HI) and dual sensory impairment (DSI) affect cognitive performance and whether depression mediates that effect. We examined 55,340 participants from the Survey of Health, Aging and Retirement in Europe, which assessed 32,325 participants in 2011 (baseline, Time 1), 2015 (follow-up, Time 2), sociodemographic data and health factors, self-reported VI, HI, and DSI at baseline, depression, and cognitive performance after four years. A multiple mediator model was tested using bootstrapping and resampling. At baseline, 22.9% had VI, 10.2% HI, and 10.4% had DSI. We found a significant negative association between VI (b = -0.023, p = .001) and DSI (b = -0.083, p = .001) and cognitive performance; both were also associated with depression, which was linked with poor cognition. VI or DSI among older adults are associated with poor cognitive function directly and indirectly by increasing depression symptoms.

Digging into the intrinsic capacity concept: Can it be applied to Alzheimer's disease?

Historically, aging research has largely centered on disease pathology rather than promoting healthy aging. The World Health Organization's (WHO) policy framework (2015-2030) underscores the significance of fostering the contributions of older individuals to their families, communities, and economies. The WHO has introduced the concept of intrinsic capacity (IC) as a key metric for healthy aging, encompassing five primary domains: locomotion, vitality, sensory, cognitive, and psychological. Past AD research, constrained by methodological limitations, has focused on single outcome measures, sidelining the complexity of the disease. Our current scientific milieu, however, is primed to adopt the IC concept. This is due to three critical considerations: (I) the decline in IC is linked to neurocognitive disorders, including AD, (II) cognition, a key component of IC, is deeply affected in AD, and (III) the cognitive decline associated with AD involves multiple factors and pathophysiological pathways. Our study explores the application of the IC concept to AD patients, offering a comprehensive model that could revolutionize the disease's diagnosis and prognosis. There is a dearth of information on the biological characteristics of IC, which are a result of complex interactions within biological systems. Employing a systems biology approach, integrating omics technologies, could aid in unraveling these interactions and understanding IC from a holistic viewpoint. This comprehensive analysis of IC could be leveraged in clinical settings, equipping healthcare providers to assess AD patients' health status more effectively and devise personalized therapeutic interventions in accordance with the precision medicine paradigm. We aimed to determine whether the IC concept could be extended from older individuals to patients with AD, thereby presenting a model that could significantly enhance the diagnosis and prognosis of this disease.

Association of mobile device proficiency and subjective cognitive complaints with financial management ability among community-dwelling older adults: a population-based cross-sectional study

BACKGROUND

Mobile devices have been used by many older adults and have the potential to assist individuals with subjective cognitive complaints (SCCs) in daily living tasks. Financial management is one of the most complex daily activity for older adults, as it is easily impaired in the prodromal stage of dementia and cognitive impairment.

AIM

To investigate financial management ability among older adults from SCCs and mobile device proficiency.

METHODS

A self-administered questionnaire was sent to 529 participants who were ≥ 65 years and regularly use mobile devices. Participants were divided into four groups based on SCC prevalence and scores of the Mobile Device Proficiency Questionnaire (MDPQ-16). Financial management abilities were compared between groups using the Process Analysis of Daily Activities for Dementia subscale. Regression model and crosstabulation table were used to investigate associations in detail.

RESULTS

A significant difference in financial management ability was observed among the four groups (p < 0.001), with the dual impairment group showed significantly lower than the robust and SCC groups (p < 0.001). Educational history, sex, and MDPQ-16 score were significantly associated with participants' financial management ability (p ≤ 0.01). The proportion of participants who could use ATMs and electronic money independently was significantly lower among those with low proficiency in mobile devices (LPM), regardless of SCC (p < 0.05).

CONCLUSION

The LPM group showed an impaired ability to manage their finances, particularly in situations where they would use information devices. Therefore, healthcare professionals should assess not only the SCC but also their proficiency with mobile devices to predict their impairment in activities of daily living.

Association between Toe Pressure Strength in the Standing Position and Maximum Walking Speed in Older Adults

BACKGROUND

Considering concerns about conventional toe grip strength, we devised a method to measure toe pressure strength in the standing position, which is close to the actual motion. This study examined the association between toe pressure strength in the standing position and walking speed among older adults.

METHODS

This cross-sectional study included 150 community-dwelling older adults (81±8 years, 73% female) who participated in the physical fitness test. We analyzed the correlation between the participants' maximum walking speed and physical function. Furthermore, we performed regression analysis with the maximum walking speed as the dependent variable to examine the association with toe pressure strength in the standing position. We also examined the association between maximum walking speed and toe pressure strength in the standing position by introducing a covariate.

RESULTS

Correlation analysis revealed a significant positive correlation between maximum walking speed and toe pressure strength in the standing position, with a moderate effect size (r=0.48, p<0.001). Moreover, multiple regression analysis with covariates showed an association between maximum walking speed and toe pressure strength in the standing position (standardization factor=0.13, p<0.026).

CONCLUSION

Toe pressure strength in the standing position was associated with maximum walking speed. This finding clarifies the significance of assessing toe pressure strength in the standing position and suggests that enhanced toe pressure strength in the standing position may increase maximum walking speed.

Comparison of toe pressure strength in the standing position and toe grip strength in association with the presence of assistance in standing up: a cross-sectional study in community-dwelling older adults

PURPOSE

We believe that toe pressure strength in the standing position, which is closer to the actual movement, is more associated with standing up in the older adults than the conventional toe grip strength. Therefore, the purpose of this study is to examine the association between toe pressure strength in the standing position and the presence of assistance in standing up in the older adults.

METHODS

Ninety-five community-dwelling older adults (82 ± 8 years old, 72% female) were included in this study. The patients were evaluated based on their need for assistance in standing up. Physical functions, including toe pressure strength in the standing position, toe grip strength, hand grip strength, knee extension strength, one-leg standing time with eyes open, and maximal walking speed, were measured.

RESULTS

When compared with and without assistance to stand up, the group requiring assistance had weaker toe pressure strength in the standing position than the group without assistance (p = 0.015, ES = 0.53). After adjusting for confounding factors, the final model revealed that toe pressure strength in the standing position was associated with the use of assistance in standing up (odds ratio 0.94 [0.88-0.99, p = 0.025]).

CONCLUSION

Toe pressure strength in the standing position was associated with the use of assistance in standing up in older adults. Improving toe pressure strength in the standing position may facilitate the ability of older adults to stand up.

Sensory Deprivation and Psychiatric Disorders: Association, Assessment and Management Strategies

BACKGROUND

Sensory deprivation (SD) is a widely prevalent condition that leads to various health-related consequences and is also an important cause of disability worldwide. Earlier, SD experiments were used as research modalities to alter human behavior. In recent years, the focus has shifted to understand how SD can affect the mental health of individuals (with congenital or acquired sensory impairments). This narrative review focuses on the current understanding about the association of SD and psychiatric disorders.

METHODS

A comprehensive literature search was done PubMed, Scopus, PsycINFO, and Google Scholar and in the cross-references of relevant articles. Keywords included "sensory deprivation," "blindness," "deafness," "mental illness," "psychiatric disorders," "prevalence," "assessment," and "management" in various combinations. Only original articles (abstract and full text) published in English till October 2020 were included.

RESULTS

The prevalence of anxiety, depression, dementia, suicidality, and psychosis in persons with SD is higher than the general population (highest being in persons with dementia with comorbid SD). Several mechanisms/hypotheses have been proposed to explain these associations. Assessment of SD includes a thorough history taking, with adequate awareness about the difficulties faced during a psychiatric interview in this population. Modifications in the psychometric assessment procedures are warranted. Management depends on a multi-disciplinary approach that includes proper referral to specialties, pharmacological management (depending on diagnosis as well as taking care of ototoxic/ocular side-effect profile of the drugs), and nonpharmacological supportive measures.

CONCLUSIONS

SD is a complex condition, and evidence suggests that persons with SD have higher psychiatric morbidity. A comprehensive assessment, along with holistic management approach is warranted.

Visual Impairment and Risk of Dementia in 2 Population-Based Prospective Cohorts: UK Biobank and EPIC-Norfolk

Visual impairment has emerged as a potential modifiable risk factor for dementia. However, there is a lack of large studies with objective measures of vision and with more than 10 years of follow-up. We investigated whether visual impairment is associated with an increased risk of incident dementia in UK Biobank and European Prospective Investigation into Cancer in Norfolk (EPIC-Norfolk). In both cohorts, visual acuity was measured using a "logarithm of the minimum angle of resolution" (LogMAR) chart and categorized as no (≤0.30 LogMAR), mild (>0.3 to ≤0.50 LogMAR), and moderate to severe (>0.50 LogMAR) impairment. Dementia was ascertained through linkage to electronic medical records. After restricting to those aged ≥60 years, without prevalent dementia and with eye measures available, the analytic samples consisted of 62 206 UK Biobank and 7 337 EPIC-Norfolk participants, respectively. In UK Biobank and EPIC-Norfolk, respectively, 1 113 and 517 participants developed dementia over 11 and 15 years of follow-up. Using multivariable Cox proportional-hazards models, the hazard ratios for mild and moderate to severe visual impairment were 1.26 (95% confidence interval [CI]: 0.92-1.72) and 2.16 (95% CI: 1.37-3.40), in UK Biobank, and 1.05 (95% CI: 0.72-1.53) and 1.93 (95% CI: 1.05-3.56) in EPIC-Norfolk, compared to no visual impairment. When excluding participants censored within 5 years of follow-up or with prevalent poor or fair self-reported health, the direction of the associations remained similar for moderate impairment but was not statistically significant. Our findings suggest visual impairment might be a promising target for dementia prevention; however, the possibility of reverse causation cannot be excluded.

Vision impairment and cognitive decline among older adults: a systematic review

OBJECTIVES

There has been increasing epidemiological research examining the association between vision impairment (VI) and cognitive impairment and how poor vision may be a modifiable risk factor for cognitive decline. The objective of this systematic review is to synthesise the published literature on the association of VI with cognitive decline, cognitive impairment or dementia, to aid the development of interventions and guide public policies pertaining to the relationship between vision and cognition.

METHODS

A literature search was performed with Embase, Medline and Cochrane library databases from inception to March 2020, and included abstracts and articles published in peer-reviewed journals in English. Our inclusion criteria included publications that contained subjective/objective measures of vision and cognition, or a diagnosis of VI, cognitive impairment or dementia. Longitudinal or cross-sectional studies with ≥100 participants aged >50 years were included. The search identified 11 805 articles whose abstracts underwent screening by three teams of study authors. Data abstraction and quality assessment using the Effective Public Health Practice Project Quality Assessment Tool were performed by one author (NN). 10% of the articles underwent abstraction and appraisal by a second author (LA/VV), results were compared between both and were in agreement.

RESULTS

110 full-text articles were selected for data extraction, of which 53 were cross-sectional, 43 longitudinal and 14 were case-control studies. The mean age of participants was 73.0 years (range 50-93.1). Ninety-one (83%) of these studies reported that VI was associated with cognitive impairment.

CONCLUSION

Our systematic review indicates that a majority of studies examining the vision-cognition relationship report that VI is associated with more cognitive decline, cognitive impairment or dementia among older adults. This synthesis supports the need for additional research to understand the mechanisms underlying the association between VI and cognitive impairment and to test interventions that mitigate the cognitive consequences of VI.

Association of Performance on Dichotic Auditory Tests With Risk for Incident Dementia and Alzheimer Dementia

Importance

Age-related hearing difficulties can include problems with signal audibility and central auditory processing. Studies have demonstrated associations between audibility and dementia risk. To our knowledge, limited data exist to determine whether audibility, central processing, or both drive these associations.

Objective

To determine the associations between signal sensitivity, central auditory processing, and dementia and Alzheimer dementia (AD) risk.

Design, Setting, and Participants

This follow-up observational study of a sample from the prospective Adult Changes in Thought study of dementia risk was conducted at Kaiser Permanente Washington, a western Washington health care delivery system, and included 280 volunteer participants without dementia who were evaluated from October 2003 to February 2006 with follow-up through September 2018. Analyses began in 2019 and continued through 2021.

Exposures

Hearing tests included pure tone signal audibility, a monaural word recognition test, and 2 dichotic tests: the Dichotic Sentence Identification (DSI) test and the Dichotic Digits test (DDT).

Main Outcomes and Measures

Cognition was assessed biennially with the Cognitive Abilities Screening Instrument (range, 1-100; higher scores are better), and scores of less than 86 prompted clinical and neuropsychological evaluations. All data were reviewed at multidisciplinary consensus conferences, and standardized criteria were used to define incident cases of dementia and probable or possible AD. Cox proportional hazard models were used to determine associations with hearing test performance.

Results

A total of 280 participants (177 women [63%]; mean [SD] age, 79.5 [5.2] years). As of September 2018, there were 2196 person-years of follow-up (mean, 7.8 years) and 89 incident cases of dementia (66 not previously analyzed), of which 84 (94.4%) were AD (63 not previously analyzed). Compared with people with DSI scores of more than 80, the dementia adjusted hazard ratio (aHR) for DSI scores of less than 50 was 4.18 (95% CI, 2.37-7.38; P < .001); for a DSI score of 50 to 80, it was 1.82 (95% CI, 1.10-3.04; P = .02). Compared with people with DDT scores of more than 80, the dementia aHR for DDT scores of less than 50 was 2.66 (95% CI, 1.31-5.42; P = .01); for a DDT score of 50 to 80, it was 2.40 (95% CI, 1.45-3.98; P = .001). The AD results were similar. Pure tone averages were weakly and insignificantly associated with dementia and AD, and associations were null when controlling for DSI scores.

Conclusions and Relevance

In this cohort study, abnormal central auditory processing as measured by dichotic tests was independently associated with dementia and AD risk.

Visual Impairment, Eye Diseases, and Dementia Risk: A Systematic Review and Meta-Analysis

BACKGROUND

Visual impairment and eye diseases have been associated with dementia, though with mixed findings and often in cross-sectional studies.

OBJECTIVE

To identify prospective studies investigating associations between visual impairment or common eye diseases and risk of all-cause dementia or key dementia subtypes.

METHODS

We searched Medline, PsycINFO, and Embase from inception to January 2020. We also conducted backward and forward citation searches of included studies and set up alerts to identify studies published after the search date. Random-effects meta-analysis was used to combine adjusted estimates across studies.

RESULTS

Thirty studies met our eligibility criteria. For visual impairment, pooled estimates indicated an increased risk of all-cause dementia (37,705 participants, 3,415 cases, risk ratio [RR] = 1.38, 95%confidence interval [CI]: 1.19-1.59, I2 = 28.6%). Pooled estimates also suggested an increased dementia risk associated with cataract (6,659 participants, 1,312 cases, hazard ratio [HR] = 1.17, 95%CI 1.00-1.38, I2 = 0.0%) and diabetic retinopathy (43,658 participants, 7,060 cases, HR = 1.34, 95%CI 1.11-1.61, I2 = 63.9%), respectively. There was no evidence of an association between glaucoma (175,357 participants, 44,144 cases, HR = 0.97, 95%CI 0.90-1.04, I2 = 51.5%) or age-related macular degeneration (7,800,692 participants, >  2,559 cases, HR = 1.15, 95%CI 0.88-1.50, I2 = 91.0%) and risk of dementia, respectively.

CONCLUSION

As visual impairment, cataract, and diabetic retinopathy are associated with an increased likelihood of developing dementia, early diagnosis may help identify those at risk of dementia. Given most causes of visual impairment are treatable or preventable, the potential for dementia prevention warrants further investigation.

Do self-reported hearing and visual impairments predict longitudinal dementia in older adults?

BACKGROUND

Sensory impairments have been associated with dementia in older adults. However, the contribution of different impairments and how they interact in the development of dementia is not clear. We examined the independent and interaction effects of hearing impairment (HI) and visual impairment (VI) on incident dementia.

DESIGN

Multi-centric population-based prospective cohort study.

SETTING

Data were taken from the AgeDifferent.de platform, pooling participants aged 75 and older from the German LEILA75+ and AgeCoDe/AgeQualiDe cohorts.

PARTICIPANTS

Older adults (N = 3497) with mean age 79.8 years, 67.2% female.

MEASUREMENTS

Standardized interviews and questionnaires were used to assess self-reported HI and VI at baseline and all-cause dementia in 9 follow-ups, spanning over 20 years.

METHODS

Competing risk regression models were conducted to test the main and interaction effects of HI and VI on dementia incidence, adjusting for established risk factors of dementia and accumulated mortality.

RESULTS

HI and VI at baseline were reported by 30.3% and 16.6% of individuals, respectively. Adjusting for baseline information on sociodemographics, substance use, cognitive functioning and morbidity, and controlling for accumulated mortality risk, HI (sHR 1.16, 95% CI 1.04-1.30, p = 0.011) but not VI (sHR 1.07, 95% CI 0.90-1.28, p = 0.462) was significantly associated with incident dementia. There was no interaction between HI and VI (sHR 1.09, 95% CI 0.81-1.46, p = 0.567).

CONCLUSIONS

Hearing impairment is associated with an increased incidence of all-cause dementia in older adults. There is no excess risk or risk compensation through the additional presence or absence of visual impairment. Early prevention measures for hearing impairment might help to reduce the long-term risk of dementia.

The Association between Vision Impairment and Incidence of Dementia and Cognitive Impairment: A Systematic Review and Meta-analysis

TOPIC

The magnitude and direction of the association between vision impairment and incident dementia and cognitive impairment in prospective cohort studies was estimated by systematic review and meta-analysis. The global burden of dementia associated with vision impairment then was estimated.

CLINICAL RELEVANCE

Because a predominant proportion of vision impairment is preventable or treatable, investigating its association with dementia may help to identify an important modifiable factor for the prevention of dementia.

METHODS

A literature search was conducted using PubMed, Embase, Web of Science, and Google Scholar on September 15, 2020. Relative risks (RRs) were pooled using random-effects models and stratified analyses for subgroups representing different study characteristics. Publication bias was evaluated with funnel plots and the Egger test. The global burden of dementia associated with vision impairment was estimated based on the Global Burden of Disease Study data on the prevalence of dementia and vision impairment.

RESULTS

In the meta-analysis of 14 prospective cohort studies with 6 204 827 participants and 171 888 dementia patients, the pooled RR associated with vision impairment was 1.47 (95% confidence interval [CI], 1.36-1.60). In the meta-analysis of 12 prospective cohort studies with 45 313 participants and 13 350 patients with cognitive impairment, the pooled RR was 1.35 (95% CI, 1.28-1.41). Stratified analyses showed that the associations of vision impairment with incident dementia and cognitive impairment were similar across methods of vision assessment, length of follow-up, and study quality. The global number of people with dementia associated with moderate or severe vision impairment in 2016 was 2.1 million (80% uncertainty interval, 1.0-3.3 million), which accounted for 4.7% (95% CI, 2.3%-7.5%) of the global burden of dementia. Economic inequality was significant for the burden of dementia associated with vision impairment.

DISCUSSION

The overall quality of the body evidence was low because of the observational design of the studies included in the analysis. Vision impairment is associated with an increased risk of both dementia and cognitive impairment in older adults. Screening and treating vision impairment, especially in low- and middle-income countries, may help to alleviate the global burden of dementia.