Somatic chronic diseases and 6-year change in cognitive functioning among older persons

Effects of Pension Eligibility Expansion on Men's Cognitive Function: Findings from Rural South Africa

Two-thirds of people living with Alzheimer's disease and related dementias (ADRD) live in low- and middle-income countries, and this figure is expected to rise as these populations are rapidly aging. Since evidence demonstrates links between socioeconomic status and slower rates of cognitive decline, protecting older adults' cognitive function in resource-limited countries that lack the infrastructure to cope with ADRD is crucial to reduce the burden it places on these populations and their health systems. While cash transfers are a promising intervention to promote healthy cognitive aging, factors such as household wealth and level of education often confound the ability to make causal inferences on the impact of cash transfers and cognitive function. This study uses a quasi-experimental design, leveraging an exogenous expansion to the Old Age Pension for men in South Africa, to approximate causal associations with cognitive function. We found evidence that there is a potential benefit of cash transfers at an earlier age for older individuals. As such, transfers such as pensions or other forms of direct basic income transfers may hold promise as potential interventions to promote healthy cognitive aging.

Cognitive Recovery After Stroke: Memory

Memory impairment occurs in over a third of patients after symptomatic stroke. Memory deficits rarely occur in isolation but are an important component of the poststroke cognitive syndrome because of the strong relationship with the risk of poststroke dementia. In this review, we summarize available data on impairment of episodic memory, with a particular emphasis on the natural history of memory impairment after stroke and the factors influencing trajectory informed by an updated systematic review. We next discuss the pathophysiology of memory impairment and mechanisms of both decline and recovery of function. We then turn to the practical issue of measurement of memory deficits after stroke, emerging biomarkers, and therapeutic approaches. Our review identifies critical gaps, particularly in studies of the natural history that properly map the long-term trajectory of memory and the associations with factors that modulate prognosis. Few studies have used advanced neuroimaging and this, in conjunction with other biomarker approaches, has the potential to provide a much richer understanding of the mechanisms at play and promising therapeutic avenues.

Technologies to improve the participation of stroke patients in their home environment

PURPOSE

To identify possible technological solutions that can contribute to stroke patients' participation at home.

METHODS

In this qualitative case study, data on factors that negatively influenced participation at home were collected via semi-structured interviews with stroke patients (n = 6). Additionally, data on possible technologies to improve this participation were collected via a group interview with experts (n = 4). The domains "cognition, mobility, self-care, and getting along" (International Classification of Functioning, Disability and Health) guided the data collection and interpretation; open, axial and selective coding was part of the analysis.

RESULTS

Patients reported 21 factors negatively influencing participation at home, including psychological, cognitive, and physical factors. Experts suggested technological solutions regarding these factors to increase participation of stroke patients; digital assistants, apps, and virtual reality were frequently mentioned. To facilitate the use of these technologies, experts indicated the importance of involving patients in their design. They also suggested that rehabilitation specialists and family members could support the uptake and use of technologies.

CONCLUSIONS

Various technologies were identified by experts as having the potential to improve the participation of stroke patients in their homes. Future research may study the influence of these technologies on the actual participation of stroke patients at home.Implications for rehabilitationThe identified technological solutions can support rehabilitation specialists in guiding stroke patients towards technologies that can support a patient's participation at home.Rehabilitation specialists can be champions in introducing, recommending and promoting technologies to stroke patients and their families, as well as in training them to use technologies.Virtual reality as a technology can be part of rehabilitation, not only to train stroke patients in daily life activities but also to increase empathy and understanding in caregivers and carers on stroke impairments.Rehabilitation specialists can recommend technologies integrated in daily life and presented as general consumer goods; stroke patients are more likely to adopt these kind of technologies.

Actor and Partner Effect of Loneliness on Episodic Memory and Verbal Fluency: A Dyadic Multilevel Analysis of Romantic Couples Across 28 Countries

OBJECTIVES

There is evidence that loneliness is detrimental to cognitive health. Most studies, however, do not consider the association between loneliness and cognition in the context of close relationships, such as a spouse or romantic partner. This study examines loneliness, experienced by both the individual and their romantic partner, and cognitive performance.

METHODS

Data were from 24,689 opposite-sex couples (49,378 participants) from 28 countries in the Survey of Health, Aging and Retirement in Europe. Each couple participant reported loneliness and completed memory and verbal fluency tasks. A multilevel sex-stratified analysis was used to account for the nested data structure and evaluate actor and partner effects of loneliness on cognitive performance for male and female partners.

RESULTS

Consistent with the literature, there were small actor effects of loneliness on memory and verbal fluency for both males and females: A person's own loneliness was associated negatively with their cognitive performance on both tasks. There were also small partner effects: A person with a partner who was lonely tended to have worse cognitive performance above and beyond their own loneliness. Actor and partners effects were similar for male and female partners, replicated in most countries, and generally held controlling for age, education, household size, and disease burden. For memory, loneliness effects were slightly stronger among older participants.

DISCUSSION

Both the experience of loneliness and loneliness of a partner have a negative association with cognitive health.

Three-year trajectories in functional limitations and cognitive decline among Dutch 75+ year olds, using nine-month intervals

Background

Using longitudinal panel data, we aimed to identify three-year trajectories in cognitive and physical functioning among Dutch older adults, and the characteristics associated with these trajectories.

Methods

We used Group-based Trajectory Modelling with mortality jointly estimated to identify trajectories, using a scale composed of 6 Activities of Daily Living (ADL) as a measure of physical functioning, and the short mini mental status examination (sMMSE) or the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) as a measure of cognitive functioning. Data came from 574 Dutch adults aged 75+, collected in five nine-month measurement waves (2015–2018) for the Longitudinal Aging Study Amsterdam.

Results

For physical functioning five trajectories were identified: ‘high’, ‘moderate’, ‘steeply declining’, ‘gradually declining’, and ‘continuously low’; and for cognitive functioning: ‘high’, ‘moderate’, ‘declining’, and ‘low’. Living in an institution, and being lower educated increased the probability of the two continuously low functioning trajectories, whereas old age and multimorbidity increased the probability of low physical functioning, but multimorbidity decreased the probability of low cognitive functioning. Associations for steeply declining physical functioning were absent. Being older and having multimorbidity increased the probability of gradually declining physical functioning and declining cognitive functioning. A higher prevalence of lung- and heart disease, cancer, and rheumatic disease was found in the gradually declining physical functioning group; and a higher prevalence of diabetes, cerebrovascular accidents, and cancer was found in the declining cognitive functioning group. High and moderate physical functioning and high cognitive functioning were characterized by being younger, community-dwelling, and higher educated. Having multimorbidity negatively predicted high and moderate physical functioning, but was not associated with high and moderate cognitive functioning.

Conclusions

This study identified trajectories comparable to studies that used longer time intervals, showing the consistent presence of heterogeneity in both physical and cognitive trajectories. Co-modelling mortality resulted in bigger group sizes for the more adverse trajectories. The favourable trajectories, containing most of the participants, were mostly characterized by absence of disease. The prevalence of chronic diseases differed between the declining trajectories, suggesting that certain diseases tend to induce cognitive decline rather than physical decline, and vice versa.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02720-x.

Do depressive symptoms link chronic diseases to cognition among older adults? Evidence from the Health and Retirement Study in the United States

BACKGROUND

Few studies have assessed psychological pathways that connect the association between non-psychotropic chronic disease and cognition. We assessed the extent to which the association between the two was mediated by depressive symptoms in older adults.

METHODS

Data came from waves 10-13 (2010-2016) of the Health and Retirement Study in the United States (7,651 men and 10,248 women). Multilevel path analysis, allowing for random intercepts and slopes, was employed to estimate the extent to which depressive symptoms mediated the total effect of a chronic disease on cognition.

RESULTS

We found that the presence of stroke, high blood pressure, diabetes, heart problems, and comorbidity, in both men and women, and lung disease in women, was associated with lower levels of cognition. The total effects of chronic diseases on cognition were partially mediated through depressive symptoms. Depressive symptoms mediated approximately 19%-39% and 23%-54% of the total effects of chronic diseases on cognition in men and women, respectively.

LIMITATIONS

We relied on self-reported diagnoses of diseases and depressive symptoms. Our use of a multilevel path analysis with random slopes precluded the inclusion of binary/categorical dependent variables, and the estimation of standardized beta values.

CONCLUSIONS

To understand the cognitive challenges that chronically ill older adults face, practitioners and policymakers should consider not just the direct symptoms related to chronic diseases, but also the often overlooked psychological conditions faced by older adults.

A prospective cohort study on longitudinal trajectories of cognitive function after stroke

The study aimed to determine longitudinal trajectories of cognitive function during the first year after stroke. The Montreal Cognitive Assessment (MoCA) was used to screen cognitive function at 36-48 h, 3-months, and 12-months post-stroke. Individuals who shared similar trajectories were classified by applying the group-based trajectory models. Data from 94 patients were included in the analysis. Three cognitive functioning groups were identified by the trajectory models: high [14 patients (15%)], medium [58 (62%)] and low [22 (23%)]. For the high and medium groups, cognitive function improved at 12 months, but this did not occur in the low group. After age, sex and education matching to the normative MoCA from the Swedish population, 52 patients (55%) were found to be cognitively impaired at baseline, and few patients had recovered at 12 months. The impact on memory differs between cognitive functioning groups, whereas the impact on activities of daily living was not different. Patients with the poorest cognitive function did not improve at one-year poststroke and were prone to severe memory problems. These findings may help to increase focus on long-term rehabilitation plans for those patients, and more accurately assess their needs and difficulties experienced in daily living.

Predictors of Post-stroke Cognition Among Geriatric Patients: The Role of Demographics, Pre-stroke Cognition, and Trajectories of Depression

Stroke is a prevalent disease among geriatric population, which tends to deteriorate cognitive ability and mental health. In such context, cognitive impairment and geriatric depression generate mutually deteriorating impacts on each other. Using the Health and Retirement Study, this study examined depression and cognition before, immediately after, and 2 years after the onset of stroke. Through latent growth mixture modeling, four different trajectories of depression were identified: resilience, recovery, emergent depression, and chronicity. We used demographics including gender, age, race, and ethnicity, activity of daily life, baseline cognition, and trajectories of depression to predict cognitive ability 2 years after the stroke. Both aforementioned demographic factors and pre-stroke cognition were predictive of post-stroke cognition, but the inclusion of depression trajectories further improved the predictive ability. Emergent depression and chronicity were two significant predictors of worse post-stroke cognition. This study showed the importance of considering a more specific trajectotrial interrelationship between depression and cognition in geriatric stroke patients.

Subjective age, depressive symptoms, and cognitive functioning across five domains

Objective: Younger subjective age predicts better episodic memory and executive functioning performance independent of chronological age. This study examined whether subjective age is associated with performance in five cognitive domains, quantified the extent to which these relationships are mediated by depressive symptoms, and tested whether these associations are moderated by chronological age.Method: Participants in this cross-sectional study included 993 adults aged 65 and older from the Health and Retirement Study's 2016 Harmonized Cognitive Assessment Protocol. Moderated mediation models estimated direct and indirect effects of subjective age on factor scores representing episodic memory, executive functioning, language, visuoconstruction, and speed through depressive symptoms and tested whether associations differed according to chronological age.Results: Depressive symptoms explained 21-32% of the associations between subjective age and language, speed, episodic memory, and executive functioning. Chronological age moderated the indirect effect involving language, such that depressive symptoms were more strongly related to worse language performance at older chronological ages. After accounting for indirect effects, direct effects of younger subjective age remained for language and speed domains.Conclusions: This study extends research on the cognitive correlates of subjective age and demonstrates that depressive symptoms partly mediate these relationships. Subjective age may bemost strongly associated with language among individuals at older chronological ages not because they are more sensitive to the negative mental health impact of feeling older than they are but because they may be particularly vulnerable to the negative effects of depressive symptoms on language ability. Additional longitudinal research is needed to determine whether links between subjective age and cognition are causal versus predictive.

Risk Prediction of Cognitive Decline after Stroke

BACKGROUND AND PURPOSE

Cognitive decline is one of the major outcomes after stroke. We have developed and evaluated a risk predictive tool of post-stroke cognitive decline and assessed its clinical utility.

METHODS

In this population-based cohort, 4,783 patients with first-ever stroke from the South London Stroke Register (1995-2010) were included in developing the model. Cognitive impairment was measured using the Mini Mental State Examination (cut off 24/30) and the Abbreviated Mental Test (cut off 8/10) at 3-months and yearly thereafter. A penalised mixed-effects linear model was developed and temporal-validated in a new cohort consisted of 1,718 stroke register participants recruited from (2011-2018). Prediction errors on discrimination and calibration were assessed. The clinical utility of the model was evaluated using prognostic accuracy measurements and decision curve analysis.

RESULTS

The overall predictive model showed good accuracy, with root mean squared error of 0.12 and R2 of 73%. Good prognostic accuracy for predicting severe cognitive decline was observed AUC: (88%, 95% CI [85-90]), (89.6%, 95% CI [86-92]), (87%, 95% CI [85-91]) at 3 months, one and 5 years respectively. Average predicted recovery patterns were analysed by age, stroke subtype, Glasgow-coma scale, and left-stroke and showed variability. DECISION: curve analysis showed an increased clinical benefit, particularly at threshold probabilities of above 15% for predictive risk of cognitive impairment.

CONCLUSIONS

The derived prognostic model seems to accurately screen the risk of post-stroke cognitive decline. Such prediction could support the development of more tailored management evaluations and identify groups for further study and future trials.

Everyday discrimination and subsequent cognitive abilities across five domains

OBJECTIVE

Previous research suggests that everyday discrimination is associated with worse concomitant performance in several cognitive domains, as well as faster subsequent declines in episodic memory. This study aimed to extend knowledge on the specificity, durability, and mechanisms of associations between everyday discrimination and cognition by using a comprehensive neuropsychological battery and a longitudinal mediation design.

METHOD

Participants included 3,304 older adults in the Health and Retirement Study Harmonized Cognitive Assessment Protocol. Discrimination was assessed using the Everyday Discrimination Scale. Depressive symptoms were assessed with the 8-item Center for Epidemiological Studies Depression Scale. Vascular diseases were quantified as the self-reported presence of hypertension, diabetes, and heart disease. Confirmatory factor analysis was used to estimate episodic memory, executive functioning, processing speed, language, and visuoconstruction across a battery of 13 neuropsychological tests. Structural equation models controlled for sociodemographics and baseline cognition ascertained 2 to 4 years prior.

RESULTS

Discrimination was associated with more depressive symptoms and vascular diseases. Depressive symptoms mediated negative effects of discrimination on subsequent functioning across all 5 cognitive domains. Vascular diseases additionally mediated negative effects of discrimination on processing speed. After accounting for mediators, direct negative effects of discrimination remained for executive functioning and visuoconstruction.

CONCLUSIONS

This national longitudinal study in the United States provides evidence for broad and enduring effects of everyday discrimination on cognitive aging, which appear to be partially mediated by mental and physical health. Future research should examine additional mechanisms as well as moderators of these associations to better understand points of intervention. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

High-frequency versus theta burst transcranial magnetic stimulation for the treatment of poststroke cognitive impairment in humans

Background

Because the reliability of repetitive transcranial magnetic stimulation (rTMS) in treating poststroke cognitive impairment has not been convincingly demonstrated, we systematically examined the effectiveness of this regimen with 2 protocols.

Methods

We randomly allocated 41 patients with poststroke cognitive impairment to receive 5 Hz rTMS (n = 11), intermittent theta burst stimulation (iTBS; n = 15) or sham stimulation (n = 15). Each group received 10 stimulation sessions over the left dorsolateral prefrontal cortex. We performed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Beck Depression Inventory at baseline and after the intervention.

Results

The 5 Hz rTMS group showed significantly greater improvement than the sham group in RBANS total score (p = 0.006), attention (p = 0.001) and delayed memory (p < 0.001). The iTBS group showed significantly greater improvement than the sham group in RBANS total score (p = 0.005) and delayed memory (p = 0.007). The 5 Hz rTMS group exhibited a superior modulating effect in attention compared to the iTBS group (p = 0.016). Patients without comorbid hypertension (p = 0.008) were predisposed to favourable therapeutic outcomes.

Limitations

Although we included only patients with left hemispheric stroke, heterogeneity associated with cortical and subcortical implications existed. We did not investigate the remote effects of rTMS.

Conclusion

Our results demonstrated that both 5 Hz rTMS and iTBS were effective for poststroke cognitive impairment in terms of global cognition, attention and memory function; the domain of attention was susceptible to 5 Hz modulation. Treatment with 5 Hz rTMS may slow cognitive decline, representing both a pivotal process in poststroke cognitive impairment and an aspect of neuroplasticity that contributes to disease-modifying strategies.

Clinical trial registration

NCT02006615; clinicaltrials.gov/ct2/show/NCT02006615.

The effect of Active Plus, a computer-tailored physical activity intervention, on cognitive functioning of elderly people with chronic illness(es) - study protocol for a randomized controlled trial

BACKGROUND

Physical activity not only is beneficial to a person's health, but can also have a positive influence on cognitive functioning. However, elderly people with chronic illness(es) often do not meet the physical activity guidelines. Physical activity programs for the elderly exist, but these are often expensive and not easily accessible to the elderly with chronic illness(es). In addition, the beneficial effects of these physical activity programs on cognitive functioning have never been specifically tested in this target group. Hence, this randomized controlled trial aims to test whether Active Plus, a proven effective physical activity intervention, is able to improve the cognitive functioning of elderly people with chronic illness(es) or to slow down cognitive decline. In addition, it studies what kind of activity, intensity, duration and frequency of physical activity most strongly influence cognitive functioning.

METHODS

A randomized controlled trial is performed, comparing the Active Plus intervention group to a waiting list control group. In total 540 older adults (≥65 years) with at least one chronic illness that limits mobility are recruited from 7 municipalities. Comparable neighborhoods within a municipality are randomly allocated to the intervention or control group. Baseline and follow-up measurements after 6 and 12 months assess cognitive functioning and physical activity behavior, measured both objectively with an accelerometer and subjectively with a self-report questionnaire. Multilevel analyses are conducted to assess effects on cognitive functioning, including analyses on moderation effects for physical activity type, frequency, duration and intensity.

DISCUSSION

To our knowledge this is the first study to investigate effectiveness of a physical activity program on cognitive functioning in elderly people suffering from a broad range of chronic illnesses. If proven effective Active Plus would be a very cost effective intervention not only to increase physical activity, but also to improve cognitive functioning or slow down cognitive decline. Up till now clear evidence is lacking on the kind of physical activity, intensity, duration and frequency needed to achieve cognitive benefits. By measuring both with accelerometers and self-report questionnaires we hope to gain insight in these processes.

TRIAL REGISTRATION

Nederlands Trial Register NL6005 ; Date of Registration 21-03-2017.

Cohort Differences in Cognitive Aging in the Longitudinal Aging Study Amsterdam

Objectives

This study aims to examine cohort differences in cognitive performance and rates of change in episodic memory, processing speed, inductive reasoning, and general cognitive performance and to investigate whether these cohort effects may be accounted for by education attainment.

Method

The first cohort (N = 705) was born between 1920 and 1930, whereas the second cohort (N = 646) was born between 1931 and 1941. Both birth cohorts were aged 65 to 75 years at baseline and were followed up 3 and 6 years later. Data were analyzed using linear mixed models.

Results

The later born cohort had better general cognitive performance, inductive reasoning, and processing speed at baseline, but cohort differences in inductive reasoning and general cognitive performance disappeared after adjusting for education. The later born cohort showed steeper decline in processing speed. Memory decline was steeper in the earlier born cohort but only from Time 1 to Time 3 when the same memory test was administered. Education did not account for cohort differences in cognitive decline.

Discussion

The later born cohort showed better initial performance in certain cognitive abilities, but no better preservation of cognitive abilities overtime compared with the earlier born cohort. These findings carry implications for healthy cognitive aging.

Combining modifiable risk factors and risk of dementia: a systematic review and meta-analysis

OBJECTIVE

To systematically review the literature relating to the impact of multiple co-occurring modifiable risk factors for cognitive decline and dementia.

DESIGN

A systematic review and meta-analysis of the literature relating to the impact of co-occurring key risk factors for incident cognitive decline and dementia. All abstracts and full text were screened independently by two reviewers and each article assessed for bias using a standard checklist. A fixed effects meta-analysis was undertaken.

DATA SOURCES

Databases Medline, Embase and PsycINFO were searched from 1999 to 2017.

ELIGIBILITY CRITERIA

For inclusion articles were required to report longitudinal data from participants free of cognitive decline at baseline, with formal assessment of cognitive function or dementia during follow-up, and an aim to examine the impact of additive or clustered comorbid risk factor burden in with two or more core modifiable risk factors.

RESULTS

Seventy-nine full-text articles were examined. Twenty-two articles (18 studies) were included reporting data on >40 000 participants. Included studies consistently reported an increased risk associated with greater numbers of intraindividual risk factors or unhealthy behaviours and the opposite for healthy or protective behaviours. A meta-analysis of studies with dementia outcomes resulted in a pooled relative risk for dementia of 1.20 (95% CI 1.04 to 1.39) for one risk factor, 1.65 (95% CI 1.40 to 1.94) for two and 2.21 (95% CI 1.78 to 2.73) for three or more, relative to no risk factors. Limitations include dependence on published results and variations in study outcome, cognitive assessment, length of follow-up and definition of risk factor exposure.

CONCLUSIONS

The strength of the reported associations, the consistency across studies and the suggestion of a dose response supports a need to keep modifiable risk factor exposure to a minimum and to avoid exposure to additional modifiable risks. Further research is needed to establish whether particular combinations of risk factors confer greater risk than others.

PROSPERO REGISTRATION NUMBER

42016052914.

Alterations of White Matter Integrity and Hippocampal Functional Connectivity in Type 2 Diabetes Without Mild Cognitive Impairment

Aims: To investigate the white matter (WM) integrity and hippocampal functional connectivity (FC) in type 2 diabetes mellitus (T2DM) patients without mild cognitive impairment (MCI) by using diffusion tensor imaging (DTI) and resting-state functional magnetic resonance imaging (rs-fMRI), respectively.

Methods: Twelve T2DM patients without MCI and 24 age, sex and education matched healthy controls (HC) were recruited. DTI and rs-fMRI data were subsequently acquired on a 3.0T MR scanner. Tract-based spatial statistics (TBSS) combining region of interests (ROIs) analysis was used to investigate the alterations of DTI metrics (fractional anisotropy (FA), mean diffusivity (MD), λ₁ and λ₂₃) and FC measurement was performed to calculate hippocampal FC with other brain regions. Cognitive function was evaluated by using Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). Brain volumes were also evaluated among these participants.

Results: There were no difference of MMSE and MoCA scores between two groups. Neither whole brain nor regional brain volume decrease was revealed in T2DM patients without MCI. DTI analysis revealed extensive WM disruptions, especially in the body of corpus callosum (CC). Significant decreases of hippocampal FC with certain brain structures were revealed, especially with the bilateral frontal cortex. Furthermore, the decreased FA in left posterior thalamic radiation (PTR) and increased MD in the splenium of CC were closely related with the decreased hippocampal FC to caudate nucleus and frontal cortex.

Conclusions: T2DM patients without MCI showed extensive WM disruptions and abnormal hippocampal FC. Moreover, the WM disruptions and abnormal hippocampal FC were closely associated.

Highlights-

T2DM patients without MCI demonstrated no obvious brain volume decrease.

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Extensive white matter disruptions, especially within the body of corpus callosum, were revealed with DTI analysis among the T2DM patients.

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Despite no MCI in T2DM patients, decreased functional connectivity between hippocampal region and some critical brain regions were detected.

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The alterations in hippocampal functional connectivity were closely associated with those of the white matter structures in T2DM patients.

This trial was registered to ClinicalTrials.gov (NCT02420470, https://www.clinicaltrials.gov/).

Longitudinal Effect of Stroke on Cognition: A Systematic Review

BACKGROUND

Stroke is associated with an increased risk of dementia; however, the impact of stroke on cognition has been found to be variable, such that stroke survivors can show decline, remain stable, or revert to baseline cognitive functioning. Knowing the natural history of cognitive impairment after stroke is important for intervention. The aim of this systematic review is to investigate the longitudinal course of cognitive function in stroke survivors.

METHODS AND RESULTS

Three electronic databases (Medline, Embase, PsycINFO) were searched using OvidSP from inception to July 15, 2016. Longitudinal studies with ≥2 time points of cognitive assessment after stroke were included. In total, 5952 articles were retrieved and 14 were included. There was a trend toward significant deterioration in cognitive test scores in stroke survivors (8 studies). Cognitive stability (3 studies) and improvement (3 studies) were also demonstrated, although follow-up time tended to be shorter in these studies. Variables associated with impairment included age, ethnicity, premorbid cognitive performance, depression, stroke location, and history of previous stroke. Associations with APOE*E4 (apolipoprotein E with the E4 allele) allele status and sex were mixed.

CONCLUSIONS

Stroke is associated with an increased risk of cognitive decline, but cognitive decline is not a consequence. Factors associated with decline, such as sociodemographic status, health-related comorbidity, stroke history, and clinical features could be used in models to predict future risk of dementia after stroke. A risk model approach could identify patients at greatest risk for timely intervention to reduce the frequency or delay the onset of poststroke cognitive impairment and dementia.

High Hemoglobin A1c and Diabetes Predict Memory Decline in the Health and Retirement Study

BACKGROUND

Type 2 diabetes (T2D) is an established risk factor for dementia, but evidence for T2D and memory decline is less consistent. Understanding how T2D and blood glucose relate to memory decline is crucial to elucidating the mechanisms linking T2D and dementia.

MATERIALS AND METHODS

For 8888 Health and Retirement Study participants aged 50+, glycosylated hemoglobin (HbA1c) was measured in either 2006 or 2008 and physician's diagnosis of diabetes was self-reported in the same year. Composite memory (z scored) was assessed biennially through 2012 using immediate and delayed word list recall or the Informant Questionnaire for Cognitive Decline. Marginal mean regression models for repeated outcomes were specified to predict memory decline as a function of diabetes or HbA1c, using age as the timescale and adjusting for health and social confounders.

RESULTS

Diabetes was associated with a 10% faster rate of memory decline [β=-0.04 per decade; 95% confidence interval (CI), -0.06 to -0.01). A 1 U increase in HbA1c corresponded with a 0.05 SD decrease in memory score per decade (95% CI, -0.08 to -0.03). Even among individuals with HbA1c<6.5% (threshold for diabetes), higher HbA1c was associated with memory decline (β=-0.05 per decade; 95% CI, -0.08 to -0.03).

DISCUSSION

Diabetes accelerated memory loss and higher HbA1c predicted memory decline even in nondiabetics.

Subjective memory complaints in elderly: relationship with health status, multimorbidity, medications, and use of services in a population-based study

BACKGROUND

This study examines the associations between subjective memory complaints (SMC) and health variables: multimorbidity, presence of certain diseases, health perceived state, difficulties seeing and hearing, pain, and use of medications and health services. Furthermore, we aim to identify risk groups based on multimorbidity and calculate the effect size for each of these relationships.

METHODS

Cross-sectional epidemiological study using a face-to-face interview with a structured questionnaire.

SAMPLE SIZE

1,342 people aged 65 years and older taken from a random sample of the census tracts. SMC were studied using questions regarding memory complaints.

RESULTS

Multimorbidity and polypharmacy are associated with SMC, so are impaired vision and hearing. SMC are more frequently present in people who use health services more intensively and exhibit reduced functional activity as a result of diseases. With respect to specific diseases, only cerebrovascular accidents and chronic constipation were associated with SMC. In regression analysis, predictors of SMC were vision and hearing impairment, poor self-perceived health, pain, and general practitioner visits. However, the effect size of these factors is low. The variables that indicate risk groups are number of diseases, reduced functional activity, hearing impairment, and poor self-perceived health.

CONCLUSIONS

Memory complaints are a heterogeneous phenomenon. Our results confirm that multimorbidity, polypharmacy, greater use of health services, pain, and poor self-perceived health are associated with SMC. We identified two risk groups with a high percentage of complaints and a healthy group with a low percentage. Detecting these factors and these risk and healthy groups is useful in achieving proper patients management.

Late-life depression symptom dimensions and cognitive functioning in the Longitudinal Aging Study Amsterdam (LASA)

BACKGROUND

Depression often co-occurs in late-life in the context of declining cognitive functions, but it is not clear whether specific depression symptom dimensions are differentially associated with cognitive abilities.

METHODS

The study sample comprised 3107 community-dwelling older adults from the Longitudinal Aging Study Amsterdam (LASA). We applied a Multiple Indicators Multiple Causes (MIMIC) model to examine the association between cognitive abilities and latent dimensions of the Center for Epidemiologic Studies Depression Scale (CES-D), while accounting for differential item functioning (DIF) due to age, gender and cognitive function levels.

RESULTS

A factor structure consisting of somatic symptoms, positive affect, depressed affect, and interpersonal difficulties fitted the data well. Higher levels of inductive reasoning were significantly associated with lower levels of depressed affect and somatic symptoms, whereas faster processing speed was significantly associated with lower levels of somatic symptoms. DIF due to age and gender was found, but the magnitude of the effects was small and did not alter substantive conclusions.

LIMITATIONS

Due to the cross-sectional context of this investigation, the direction of influence between depression symptom levels and cognitive function levels cannot be established. Furthermore, findings are relevant to non-clinical populations, and they do not clarify whether certain DIF effects may be found only at high or low levels of depression.

CONCLUSIONS

Our findings suggest differential associations between late-life depression dimensions and cognitive abilities in old age, and point towards potential etiological mechanisms that may underline these associations. These findings carry implications for the prognosis of cognitive outcomes in depressed older adults.

Does type 2 diabetes increase rate of cognitive decline in older Mexican Americans?

Estimating effects of diabetes on cognitive change among older Mexican Americans is important, yet challenging, because diabetes and cognitive decline both predict mortality, which can induce survival bias. Older Mexican Americans in the Sacramento Area Latino Study on Aging (n=1634) completed Modified Mini-Mental State Exams (3MSE) and diabetes assessments up to 7 times (from 1998 to 2007). We examined baseline and new-onset diabetes and cognitive decline with joint longitudinal-survival models to account for death. At baseline, 32.4% of participants had diabetes and 15.8% developed diabetes during the study. During the study period, 22.8% of participants died. In joint longitudinal-survival models, those with baseline diabetes experienced faster cognitive decline (P=0.003) and higher mortality (hazards ratio=1.88; 95% confidence interval, 1.48-2.38) than those without diabetes. Cognitive decline and mortality were similar for those with new-onset diabetes and those without diabetes. For a typical person, 3MSE scores declined by 2.3 points among those without diabetes and 4.3 points among those with baseline diabetes, during the last 6 years of study. Ignoring the impact of death yielded a 17.0% smaller estimate of the effect of baseline diabetes on cognitive decline. Analyses that overlook the association between cognitive decline and mortality may underestimate the effect of diabetes on cognitive aging.

Cognitive deterioration in adult epilepsy: Does accelerated cognitive ageing exist?

A long-standing concern has been whether epilepsy contributes to cognitive decline or so-called 'epileptic dementia'. Although global cognitive decline is generally reported in the context of chronic refractory epilepsy, it is largely unknown what percentage of patients is at risk for decline. This review is focused on the identification of risk factors and characterization of aberrant cognitive trajectories in epilepsy. Evidence is found that the cognitive trajectory of patients with epilepsy over time differs from processes of cognitive ageing in healthy people, especially in adulthood-onset epilepsy. Cognitive deterioration in these patients seems to develop in a 'second hit model' and occurs when epilepsy hits on a brain that is already vulnerable or vice versa when comorbid problems develop in a person with epilepsy. Processes of ageing may be accelerated due to loss of brain plasticity and cognitive reserve capacity for which we coin the term 'accelerated cognitive ageing'. We believe that the concept of accelerated cognitive ageing can be helpful in providing a framework understanding global cognitive deterioration in epilepsy.

Vitamin K Status Is not Associated with Cognitive Decline in Middle Aged Adults

OBJECTIVES

The aim of this study was to examine the association between dephospho-uncarboxylated matrix Gla protein (dp-ucMGP), an indicator of vitamin K status, and cognitive decline, and the modifying role of 25(OH)D.

DESIGN

Longitudinal study with six years follow-up.

SETTING

Community based.

PARTICIPANTS

599 participants of the Longitudinal Aging Study Amsterdam (aged 55-65 years).

MEASUREMENTS

Information processing speed and a composite Z-score by combining three domains of cognition reflecting general cognitive functioning.

RESULTS

Generalized estimating equations (GEE) showed no significant associations between dp-ucMGP and decline in general cognitive functioning. Vitamin D modified the association between dp-ucMGP and speed of information processing (p<0.05). In the group with a 25(OH)D concentration > 50 nmol/l, the highest tertile of dp-ucMGP (>406 pmol/l), which corresponds to lower vitamin K levels, was associated with 1.5 higher score on information processing speed (p=0.023) as compared to the lowest tertile of dp-ucMGP.

CONCLUSION

In contrast to our hypothesis, a suboptimal vitamin K was not associated with cognitive decline in middle-aged adults.

Correlates of Incident Cognitive Impairment in the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

OBJECTIVE

To identify approximately 500 cases of incident cognitive impairment (ICI) in a large, national sample adapting an existing cognitive test-based case definition and to examine relationships of vascular risk factors with ICI.

METHOD

Participants were from the REGARDS study, a national sample of 30,239 African-American and White Americans. Participants included in this analysis had normal cognitive screening and no history of stroke at baseline, and at least one follow-up cognitive assessment with a three-test battery (TTB). Regression-based norms were applied to TTB scores to identify cases of ICI. Logistic regression was used to model associations with baseline vascular risk factors.

RESULTS

We identified 495 participants with ICI of 17,630 eligible participants. In multivariable modeling, income (OR 1.83 CI 1.27,2.62), stroke belt residence (OR 1.45 CI 1.18,1.78), history of transient ischemic attack (OR 1.90 CI 1.29,2.81), coronary artery disease(OR 1.32 CI 1.02,1.70), diabetes (OR 1.48 CI 1.17,1.87), obesity (OR 1.40 CI 1.05,1.86), and incident stroke (OR 2.73 CI 1.52,4.90) were associated with ICI.

CONCLUSIONS

We adapted a previously validated cognitive test-based case definition to identify cases of ICI. Many previously identified risk factors were associated with ICI, supporting the criterion-related validity of our definition.

Diabetes and cognition

Dementia is a major cause of disability and death among older adults. Those with type 2 diabetes (T2D) are 50-100% more likely to develop dementia than those without T2D, but it is unknown whether this association reflects a causal relationship. Proposed mechanisms through which T2D could cause dementia include the effects of insulin dysregulation and chronic hyperglycemia on features of Alzheimer's disease and macrovascular and microvascular disorders in the brain. More research is needed to elucidate the link between T2D and dementia and identify strategies to maintain cognitive function among people with T2D.

Type 2 diabetes and cognitive decline over 14 years in middle-aged African Americans and whites: the ARIC Brain MRI Study

BACKGROUND

Diabetes predicts late-life dementia, but the association with rate of cognitive decline is inconsistent and has rarely been examined in non-white populations, despite the high prevalence of diabetes in African Americans. We evaluated the effect of diabetes on cognitive decline in middle-aged African Americans and whites.

METHODS

Atherosclerosis Risk in Communities (ARIC) Brain MRI Study participants (n = 1,886, mean age = 60, 49% African American) underwent assessments of verbal memory, processing speed, and verbal fluency four times over 14 years. Using race-stratified mixed linear effects models, we examined cognitive change for participants with prevalent (baseline) diabetes and incident (diagnosed after baseline) diabetes versus those without diabetes.

RESULTS

African Americans had more advanced diabetes, as indicated by fasting blood glucose levels, anti-diabetes medication use, and cardiovascular risk profiles. African Americans with prevalent diabetes experienced 41% greater annual decline in processing speed scores (p = 0.048) and 50% greater annual decline in verbal fluency scores (p = 0.042) than those without diabetes; incident diabetes was not associated with cognitive decline. Among whites, diabetes was not associated with cognitive decline.

CONCLUSIONS

Prevalent diabetes was associated with greater cognitive decline in middle-aged African Americans, possibly reflecting adverse effects of longer duration and more advanced diabetes.

Update on cognitive decline and dementia in elderly patients with diabetes

AIM

This article is an update of the relationship between type 2 diabetes (T2D), cognitive dysfunction and dementia in older people.

METHODS AND RESULTS

The number of older patients consulting for diabetes who also exhibit cognitive difficulties is consistently growing because of the increased longevity of the population as a whole and, according to a number of studies, the increased risk of cognitive impairment and dementia in older diabetic patients. Many studies have demonstrated a link between poor glucose control and deteriorated cognitive function in diabetic patients. A history of severe hypoglycaemic episodes has also been associated with a greater risk of late-in-life cognitive deficits and dementia in patients with T2D. Several processes are thought to promote cognitive decline and dementia in diabetics. Based on both clinical and non-clinical findings, the factors most likely to alter brain function and structure are cerebrovascular complications of diabetes, alterations in glucose and insulin, and recurrent hypoglycaemia. Together with other diabetes complications, cognitive deficits contribute to functional impairment, increased frequency of depression-related symptoms, greater incidence of recurrent hypoglycaemia, poorer adherence to treatment and, finally, poorer prognosis, as evidenced by recent longitudinal studies.

CONCLUSION

Clinical guidelines have recently been devised for older diabetic patients, particularly those with cognitive deficits and a reduced capacity to self-manage. In the most vulnerable patients, specific treatment strategies have been proposed for glycaemic control to limit metabolic decompensation and avoid the risk of hypoglycaemia. Educational measures, provided mainly to maintain patient autonomy and avoid hospital admission, have also been adapted according to patients' cognitive and functional status.

Rate of cognitive decline in relation to sex after 60 years-of-age: a systematic review

Some studies have shown differences in specific cognitive ability domains between the sexes at 60 years-of-age. However is important to analyze whether the rate of cognitive decline is also similar between the sexes after this age. The present study examined previously published literature to investigate whether cognitive decline is distinct between men and women after the age of 60 years. A systematic review was carried out with the PubMed, LILACS and PsycINFO databases (2001-2011) using the following search terms: aging, aged, cognitive function, mild cognitive impairment, mental health and cognition. We analyzed longitudinal research that used neuropsychological tests for evaluating cognitive function, showed results separated by sex and that excluded participants with dementia. Elderly women showed better performance in tests of episodic memory, whereas elderly men had a better visuospatial ability. Only one study detected distinct rates of cognitive decline in specific tests between the sexes. Despite differences observed in some domains, most of the studies showed that this rate is similar between the sexes until the age of 80 years. It is unclear whether sex influences the rate of cognitive decline after the age of 80 years. The present review observed that sex does not determine the rate of cognitive decline between 60 and 80 years-of-age. The contextual and cultural factors that involve men and women might determine a distinct decline between them, rather than sex alone.

Do employed and not employed 55 to 64-year-olds' memory complaints relate to memory performance? A longitudinal cohort study

BACKGROUND

Whether middle-aged individuals are capable of employment continuation may be limited by poor memory. Subjective memory complaints may be used to identify those at risk of poor memory. Research questions, therefore, were (i) are prevalent memory complaints associated with relevantly poor memory performance and decline in 55 to 64-year-olds; (ii) are incident memory complaints associated with relevant memory decline; and (iii) do these associations differ between employed and not employed individuals?

METHODS

Participants of the Longitudinal Aging Study Amsterdam (LASA) were examined. Data were weighted by sex, age and region. To examine the association of prevalent memory complaints with relevantly poor learning ability (n=903) and delayed recall (n=897; both assessed with the Auditory Verbal Learning Test), subnormal (≤ mean-1 SD) and impaired (≤ mean-1.5 SD) memory performance were defined. To examine the association of prevalent and incident memory complaints with relevant decline after 3 years in learning ability (n=774 and 611, respectively) and delayed recall (n=768 and 603, respectively), above normal (≤ mean-1 SD) and clinically relevant (≤ mean-1.5 SD) memory decline were investigated. Logistic regression analyses were applied.

RESULTS

Adjusted for gender, education and age, individuals with memory complaints more often had impaired delayed recall and clinically relevant decline in learning ability. Incident memory complaints were borderline significantly associated with clinically relevant decline in learning in continuously employed individuals (paid job ≥ 1 h weekly), but not in continuously not employed individuals.

CONCLUSION

Memory complaints may identify 55 to 64-year-olds at risk of memory impairment and decline. Our results provide hypotheses about the association between memory complaints and decline in employed 55 to 64-year-olds.

Influence of multimorbidity on cognition in a normal aging population: a 12-year follow-up in the Maastricht Aging Study

OBJECTIVE

The prevalence of multimorbidity has risen considerably because of the increase in longevity and the rapidly growing number of older individuals. Today, only little is known about the influence of multimorbidity on cognition in a normal healthy aging population. The primary aim of the present study was to investigate the effect of multimorbidity on cognition over a 12-year period in an adult population with a large age range.

METHODS

Data were collected as part of the Maastricht Aging Study (MAAS), a prospective study into the determinants of cognitive aging. Eligible MAAS participants (N = 1763), 24-81 years older, were recruited from the Registration Network Family Practices (RNH) which enabled the use of medical records. The association between 96 chronic diseases, grouped into 23 disease clusters, and cognition on baseline, at 6 and 12 years of follow-up, were analyzed. Cognitive performance was measured in two main domains: verbal memory and psychomotor speed. A multilevel statistical analysis, a method that respects the hierarchical data structure, was used.

RESULTS

Multiple disease clusters were associated with cognition during a 12-year follow-up period in a healthy adult population. The disease combination malignancies and movement disorders multimorbidity also appeared to significantly affect cognition.

CONCLUSIONS

The current results indicate that a variety of medical conditions adversely affects cognition. However, these effects appear to be small in a normal healthy aging population.

An evaluation of analytical approaches for understanding change in cognition in the context of aging and health

OBJECTIVES

In this article, we discuss the importance of studying the relationship between health and cognitive function, and some of the methods with which this relationship has been studied.

METHODS

We consider the challenges involved, in particular operationalization of the health construct and causal inference in the context of observational data. We contrast the approaches taken, and review the questions addressed: whether health and cognition are associated, whether changes in health are associated with changes in cognition, and the degree of interdependency among their respective trajectories.

RESULTS

A variety of approaches for understanding the association between cognition and health in aging individuals have been used. Much of the literature on cognitive change and health has relied on methods that are based at least in part on the reorganization of between-person differences (e.g., cross-lag analysis) rather than relying more fully on analysis of within-person change and joint analysis of individual differences in within-person change in cognition and health.

DISCUSSION

We make the case for focusing on the interdependency between within-person changes in health and cognition and suggest methods that would support this.

Multimorbidity and its relation to subjective memory complaints in a large general population of older adults

BACKGROUND

Multimorbidity has been suggested to be associated with a variety of negative health-related outcomes. The present study was designed to evaluate the association between multimorbidity and subjective memory complaints.

METHODS

This cross-sectional study was based on data obtained from a postal survey designed by the Public Health Service (Gemeentelijke Gezondheids Dienst, GGD) involving 15,188 persons aged 55 years and over living independently in Limburg, the Netherlands. Multivariate logistic regression analyses, adjusted for potentially important covariates, were performed to evaluate the association between self-reported multimorbidity and three outcomes related to subjective memory complaints.

RESULTS

Multimorbidity was indeed related to subjective memory complaints. The association between multimorbidity and subjective memory complaints was positively influenced by age. Moreover, multimorbidity was related to the degree of worrying about memory complaints in people who perceived themselves as forgetful. Multimorbidity was also associated with reporting a larger increase in these subjective memory complaints during the past year. In this latter case, multimorbidity had more prognostic capability in men than in women. Psychological distress was related to all three subjective memory-related outcome measures.

CONCLUSIONS

In our sample, which was representative of the Dutch population, multimorbidity was associated with subjective memory complaints. The relationship between multimorbidity and subjective memory complaints differed between men and women and between age groups.

Socio-demographic and health-related factors associated with cognitive impairment in the elderly in Taiwan

Background

Cognitive impairment is an age-related condition as the rate of cognitive decline rapidly increases with aging. It is especially important to better understand factors involving in cognitive decline for the countries where the older population is growing rapidly. The aim of this study was to examine the association between socio-demographic and health-related factors and cognitive impairment in the elderly in Taiwan.

Methods

We analysed data from 2119 persons aged 65 years and over who participated in the 2005 National Health Interview Survey. Cognitive impairment was defined as having the score of the Mini Mental State Examination lower than 24. The χ² test and multiple logistic regression models were used to evaluate the association between cognitive impairment and variables of socio-demography, chronic diseases, geriatric conditions, lifestyle, and dietary factors.

Results

The prevalence of cognitive impairment was 22.2%. Results of multivariate analysis indicated that low education, being single, low social support, lower lipid level, history of stroke, physical inactivity, non-coffee drinking and poor physical function were associated with a higher risk of cognitive impairment.

Conclusion

Most of the characteristics in relation to cognitive impairment identified in our analysis are potentially modifiable. These results suggest that improving lifestyle behaviours such as regular exercise and increased social participation could help prevent or decrease the risk of cognitive impairment. Further investigations using longitudinal data are needed to clarify our findings.

Intelligence in youth and all-cause-mortality: systematic review with meta-analysis

BACKGROUND

A number of prospective cohort studies have examined the association between intelligence in childhood or youth and life expectancy in adulthood; however, the effect size of this association is yet to be quantified and previous reviews require updating.

METHODS

The systematic review included an electronic search of EMBASE, MEDLINE and PSYCHINFO databases. This yielded 16 unrelated studies that met inclusion criteria, comprising 22,453 deaths among 1,107,022 participants. Heterogeneity was assessed, and fixed effects models were applied to the aggregate data. Publication bias was evaluated, and sensitivity analyses were conducted.

RESULTS

A 1-standard deviation (SD) advantage in cognitive test scores was associated with a 24% (95% confidence interval 23-25) lower risk of death, during a 17- to 69-year follow-up. There was little evidence of publication bias (Egger's intercept = 0.10, P = 0.81), and the intelligence-mortality association was similar for men and women. Adjustment for childhood socio-economic status (SES) in the nine studies containing these data had almost no impact on this relationship, suggesting that this is not a confounder of the intelligence-mortality association. Controlling for adult SES in five studies and for education in six studies attenuated the intelligence-mortality hazard ratios by 34 and 54%, respectively.

CONCLUSIONS

Future investigations should address the extent to which attenuation of the intelligence-mortality link by adult SES indicators is due to mediation, over-adjustment and/or confounding. The explanation(s) for association between higher early-life intelligence and lower risk of adult mortality require further elucidation.