Free Recall Episodic Memory Performance Predicts Dementia Ten Years prior to Clinical Diagnosis: Findings from the Betula Longitudinal Study

Lifestyle factors associated with episodic memory in middle-aged and older adults: evidence from a 9-year longitudinal study

BACKGROUND

Episodic memory naturally deteriorates with age, and its deficits are widely recognized as the most significant feature and the most sensitive indicator of cognitive decline. It has been suggested that adopting a healthy lifestyle can play a protective role in preserving episodic memory. This study aimed to systematically examine the relationship between lifestyle factors (social activities, leisure activities, physical activities, internet use, smoking, alcohol drinking, and sleep quality) and episodic memory in middle-aged and older adults.

METHODS

The current study included 10,392 participants from the Chinese Health and Retirement Longitudinal Survey. A linear mixed model was used to explore the associations between lifestyle factors and episodic memory performance and the age- and sex-specific effects of the association.

RESULTS

Low-frequency alcohol drinking, higher engagement in social, leisure, and physical activities, increased internet use, and improved sleep quality were associated with better episodic memory performance in middle-aged and older adults. Stratified analyses demonstrated that internet use significantly correlated with episodic memory performance in middle-aged adults but not in older adults. On the other hand, sleep quality showed a significant association with episodic memory performance in women but not in men.

CONCLUSIONS

This study highlights the association between various lifestyle factors and episodic memory performance, with variations observed based on age and sex. Adopting healthy lifestyle factors can have positive effects on episodic memory in middle-aged adults, emphasizing the importance of adhering to healthy lifestyles from middle age onwards to counteract episodic memory decline.

The association between dynamic balance and executive function: Which dynamic balance test has the strongest association with executive function? A systematic review and meta-analysis

AIM

The aging global population poses increasing challenges related to falls and dementia. Early identification of cognitive decline, particularly before noticeable symptoms manifest, is crucial for effective intervention. This review aims to determine the dynamic balance test most closely associated with executive function, potentially serving as a biomarker for cognitive decline.

RECENT FINDINGS

Based on recent reviews, inhibitory control, a component of executive function, holds significance in influencing balance performance. Studies suggest that the strength of the correlation between cognition and balance tends to be domain-specific and task-specific. Despite these findings, inconclusive evidence remains regarding the connection between executive function and various dynamic balance assessments. Our review identifies a significant association between all dynamic balance tests and executive function, albeit with varying strengths. Notably, a medium effect size is observed for the Timed Up and Go and Functional Reach Test, a small effect size for balance scales, and a strong effect size for postural sway. This review underscores a clear relationship between dynamic balance task performance and executive function. Dynamic posturography holds potential as a clinical biomarker for early detection of cognitive decline, with a note of caution due to observed heterogeneity and limited studies.

Trajectories of activities of daily living according to dementia among middle-aged and older people in South Korea: a longitudinal study from 2006 to 2020 (14 years)

Introduction

The aging population in South Korea faces numerous health challenges, one of which is the decline in Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL). This study aims to investigate the patterns of change in ADL and IADL among older adults and examines how these patterns vary between individuals with and without dementia.

Methods

We conducted an analysis of data collected from the Korea Longitudinal Study of Ageing (KLoSA) between 2006 and 2022. Our cohort consisted of individuals aged 45 and older with non-dementia conditions, including mild cognitive impairment (N=6042), and a smaller group with dementia (N=91). Using Latent Growth Curve Models, we explored the developmental trajectories of ADL and IADL among our sample.

Results

Our findings indicate a linear decline in both ADL and IADL scores as individuals age. The decline in IADL was more pronounced in the dementia group, suggesting a greater sensitivity to sociocultural factors within this domain. The data revealed that individuals with dementia had consistently lower ADL and IADL scores. Notably, the variance in scores within the dementia group increased with age, signifying a worsening in daily living performance and an increase in individual variation (F=226.630, p<.001).

Discussion

The results of this study underscore the impact of dementia on both the self-regulation function and the social and cultural aspects of daily living performance, particularly reflected in IADL scores. These findings point to the necessity for comprehensive care strategies that address the multifaceted needs of older adults with dementia, including support for complex daily activities that are influenced by sociocultural factors.

Multi-domain cognition dysfunction accompanies frontoparietal and temporal amyloid accumulation in the elderly

It is helpful to understand the pathology of Alzheimer's disease by exploring the relationship between amyloid-β accumulation and cognition. The study explored the relationship between regional amyloid-β accumulation and multiple cognitions and study their application value in the Alzheimer's disease diagnosis. 135 participants completed 18F-florbetapir Positron Emission Tomography (PET), structural MRI, and a cognitive battery. Partial correlation was used to examine the relationship between global and regional amyloid-β accumulation and cognitions. Then, a support vector machine was applied to determine whether cognition-related accumulation regions can adequately distinguish the cognitively normal controls (76 participants) and mild cognitive impairment (30 participants) groups or mild cognitive impairment and Alzheimer's disease (29 participants) groups. The result showed that amyloid-β accumulation regions were mainly located in the frontoparietal cortex, calcarine fissure, and surrounding cortex and temporal pole regions. Episodic memory-related regions included the frontoparietal cortices; executive function-related regions included the frontoparietal, temporal, and occipital cortices; and processing speed-related regions included the frontal and occipital cortices. Support vector machine analysis showed that only episodic memory-related amyloid-β accumulation regions had better classification performance during the progression of Alzheimer's disease. Assessing regional changes in amyloid, particularly in frontoparietal regions, can aid in the early detection of amyloid-related decline in cognitive function.

Sex differences in longitudinal changes of episodic memory-related brain activity and cognition in cognitively unimpaired older adults with a family history of Alzheimer's disease

Episodic memory decline is an early symptom of Alzheimer's disease (AD) - a neurodegenerative disease that has a higher prevalence rate in older females compared to older males. However, little is known about why these sex differences in prevalence rate exist. In the current longitudinal task fMRI study, we explored whether there were sex differences in the patterns of memory decline and brain activity during object-location (spatial context) encoding and retrieval in a large sample of cognitively unimpaired older adults from the Pre-symptomatic Evaluation of Novel or Experimental Treatments for Alzheimer's Disease (PREVENT-AD) program who are at heightened risk of developing AD due to having a family history (+FH) of the disease. The goal of the study was to gain insight into whether there are sex differences in the neural correlates of episodic memory decline, which may advance knowledge about sex-specific patterns in the natural progression to AD. Our results indicate that +FH females performed better than +FH males at both baseline and follow-up on neuropsychological and task fMRI measures of episodic memory. Moreover, multivariate data-driven task fMRI analysis identified generalized patterns of longitudinal decline in medial temporal lobe activity that was paralleled by longitudinal increases in lateral prefrontal cortex, caudate and midline cortical activity during successful episodic retrieval and novelty detection in +FH males, but not females. Post-hoc analyses indicated that higher education had a stronger effect on +FH females neuropsychological scores compared to +FH males. We conclude that higher educational attainment may have a greater neuroprotective effect in older +FH females compared to +FH males.

Longitudinal trajectories of memory among middle-aged and older people with hearing loss: the influence of cochlear implant use on cognitive functioning

Introduction

Cochlear implants (CI) are the gold standard intervention for severe to profound hearing loss, a known modifiable risk factor for dementia. However, it remains unknown whether CI use might prevent the age-related cognitive decline. Recent studies are encouraging but are limited, mainly by short follow-up periods and, for ethical reasons, lack of appropriate control groups. Further, as age-related cognitive decline is multifaceted and not linear, other statistical approaches have to be evaluated.

Materials and methods

Immediate and delayed recall as measures of cognitive function were assessed in 75 newly implanted CI users (mean age 65.41 years ± 9.19) for up to 5 years (mean 4.5 ± 0.5) of CI use and compared to 8,077 subjects of the same age range from two longitudinal cohort studies, the Health and Retirement Study (HRS) and the English Longitudinal Study of Aging (ELSA). Linear and quadratic changes in cognitive trajectories were analyzed in detail using mixed growth models, considering possible confounders.

Results

For CI users, the linear time slope showed a significant improvement in the specific domains (recall and delayed recall) over time. The quadratic time slope clearly indicated that the predicted change after CI provision followed an inverted U-shape with a predicted decline 2 years after CI provision. In the hearing-impaired group, a significant decline over time was found, with steeper declines early on and the tendency to flatten out in the follow-up.

Conclusion

Cochlear implant use seems to boost cognitive trajectories in the first years after implantation. However, long-term prevention of dementia seems to need far more than restoration of hearing loss.

Decoding the heterogeneity of Alzheimer's disease diagnosis and progression using multilayer networks

Alzheimer's disease (AD) is a multifactorial and heterogeneous disorder, which makes early detection a challenge. Studies have attempted to combine biomarkers to improve AD detection and predict progression. However, most of the existing work reports results in parallel or compares normalized findings but does not analyze data simultaneously. We tested a multi-dimensional network framework, applied to 490 subjects (cognitively normal [CN] = 147; mild cognitive impairment [MCI] = 287; AD = 56) from ADNI, to create a single model capable of capturing the heterogeneity and progression of AD. First, we constructed subject similarity networks for structural magnetic resonance imaging, amyloid-β positron emission tomography, cerebrospinal fluid, cognition, and genetics data and then applied multilayer community detection to find groups with shared similarities across modalities. Individuals were also followed-up longitudinally, with AD subjects having, on average, 4.5 years of follow-up. Our findings show that multilayer community detection allows for accurate identification of present and future AD (≈90%) and is also able to identify cases that were misdiagnosed clinically. From all MCI participants who developed AD or reverted to CN, the multilayer model correctly identified 90.8% and 88.5% of cases respectively. We observed similar subtypes across the full sample and when examining multimodal data from subjects with no AD pathology (i.e., amyloid negative). Finally, these results were also validated using an independent testing set. In summary, the multilayer framework is successful in detecting AD and provides unique insight into the heterogeneity of the disease by identifying subtypes that share similar multidisciplinary profiles of neurological, cognitive, pathological, and genetics information.

Cognitive differences across ethnoracial category, socioeconomic status across the Alzheimer's disease spectrum: Can an ability discrepancy score level the playing field?

An ability discrepancy (crystallized minus fluid abilities) might be a personally relevant cognitive marker of risk for Alzheimer's disease (AD) and might help reduce measurement bias often present in traditional measures of cognition. In a large national sample of adults aged 60-104 years (N = 14,257), we investigated whether the intersectionality of group characteristics previously shown to pose a risk for AD including ethnoracial category, socioeconomic status, and sex (a) differed in ability discrepancy compared to traditional neuropsychological tests and (b) moderated the relationship between an ability discrepancy and AD symptom severity. In cognitively normal older adults, results indicated that across each decade, fluid and memory composite scores generally exhibited large group differences with sex, education, and ethnoracial category. In contrast, the ability discrepancy score showed much smaller group differences, thus removing much of the biases inherent in the tests. Women with higher education differed in discrepancy performance from other groups, suggesting a subgroup in which this score might reduce bias to a lesser extent. Importantly, a greater ability discrepancy was associated with greater AD symptom severity across the AD continuum. Subgroup analyses suggest that this relationship holds for all groups except for some subgroups of Hispanic Americans. These findings suggest that an ability discrepancy measure might be a better indicator of baseline cognition than traditional measures that show more egregious measurement bias across diverse groups of people.

Trajectories of cognitive decline and dementia development: A 12-year longitudinal study

INTRODUCTION

Mapping the preclinical dementia phase is important for early detection and evaluation of interventions. We assessed the trajectories of cognitive decline in preclinical dementia over 12 years and investigated whether being a fast decliner across 6 years is associated with increased risk of dementia the following 6 years.

METHODS

Rates of cognitive decline were determined using mixed-effects models for 1646 participants from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) cohort. Cox regression was used to assess the future likelihood of dementia for fast decliners (declining ≥1.5 standard deviations [SDs] faster than the age-specific rates).

RESULTS

Participants in a preclinical phase of dementia showed increased rates of decline in all cognitive tests compared to the no-dementia group, particularly closer (0-6 years) to diagnosis. Participants declining fast in three or more cognitive tests 12-6 years before diagnosis demonstrated a high risk of dementia 6 years later (hazard ratio [HR] 3.90, 95% confidence interval [CI] 2.28-6.69).

DISCUSSION

Being a fast decliner is linked to increased risk of future dementia.

A Simple Single Item Rated by an Interviewer Predicts Incident Dementia Over 15 Years

Subjective memory is useful to detect cognitive deficits not apparent on objective tests. This research evaluates whether memory rated by an interviewer predicts incident dementia. Health and Retirement Study participants without cognitive impairment at baseline whose memory was rated by the interviewer were analyzed (N = 12,749). Worse interviewer-rated memory was associated with higher risk of incident dementia over 15 years (HR = 1.40, 95% CI = 1.27-1.54). The association was evident even among participants in the top quartile of objective memory performance (HR = 1.71, 95% CI = 1.26-2.32). Interviewer-rated memory may be a low-cost supplement to neuropsychological evaluation to predict dementia risk beyond self-reports and objective cognitive testing.

Social engagement and its links to cognition differ across non-Hispanic Black and White older adults

OBJECTIVE

Racial inequalities in dementia have been linked to disparities in socioeconomic status, chronic diseases, and psychosocial stress. Less focus has been given to psychosocial protective factors. Previous studies suggest that social engagement promotes better cognitive aging, but few have examined whether social engagement or its associations with cognition vary across non-Hispanic Whites (NHW) and Blacks (NHB).

METHOD

Participants included 465 adults (53% NHB) from the Michigan Cognitive Aging Project (Mage = 63.59 ± 3.15) who completed a comprehensive neuropsychological battery. Social engagement was operationalized as network size, frequency of social activity participation, and social support. Cognition was operationalized using factor scores corresponding to five domains: episodic memory, executive functioning, processing speed, language, and visuospatial functioning. Cross-sectional associations between social engagement and cognitive outcomes were examined using race-stratified regressions controlling for age, sex/gender, education, wealth, marital status, depressive symptoms, and chronic diseases.

RESULTS

There were no racial differences in social network size or social support. NHB participants reported less social activity participation than NHW participants. Social activity participation was positively associated with memory in NHW, but not NHB.

CONCLUSIONS

These findings may suggest a threshold effect whereby NHB older adults are less likely to participate in social activities at the level needed to yield cognitive benefits. Lower social activity participation among NHB may reflect structural barriers and/or cultural differences in patterns of social engagement. This study highlights the need to improve measurement of and access to culturally relevant social activities for NHB to combat racial inequalities in cognitive aging. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Episodic Memory in Amnestic Mild Cognitive Impairment (aMCI) and Alzheimer’s Disease Dementia (ADD): Using the “Doors and People” Tool to Differentiate between Early aMCI—Late aMCI—Mild ADD Diagnostic Groups

Episodic memory is the type of memory that allows the recollection of personal experiences containing information on what has happened and, also, where and when it happened. Because of its sensitivity to neurodegenerative diseases and the aging of the brain, it is considered a hallmark of Alzheimer’s disease dementia (ADD). The objective of the present study was to examine episodic memory in amnestic mild cognitive impairment (aMCI) and ADD. Patients with the diagnosis of early aMCI, late aMCI, and mild ADD were evaluated using the Doors and People tool which consists of four subtests examining different aspects of episodic memory. The statistical analysis with receiver operating characteristic curves (ROC) showed the discriminant potential and the cutoffs of every subtest. Overall, the evaluation of episodic memory with the Doors and People tool can discriminate with great sensitivity between the different groups of people with AD and, especially, early aMCI, late aMCI, and mild ADD patients.

Validation and Normative Data of the Spanish Version of the Rey Auditory Verbal Learning Test and Associated Long-Term Forgetting Measures in Middle-Aged Adults

Rey Auditory Verbal Learning Test (RAVLT) is an episodic memory helpful measure to detect changes associated with abnormal aging. There is a lack of RAVLT validation and normalization studies in Spain. The aim was to determine its psychometric properties and explore long-term forgetting (LTF) performance through 1-week delayed recall under three different modes of administration. The RAVLT was administered to 602 cognitively healthy volunteers, aged between 41 and 65 years, of whom 251 completed the LTF assessment. Findings reveal a factorial structure of four components, with satisfactory goodness of fit, and adequate convergent and divergent validity. We also demonstrated the differential effect of three methodologies used in LTF assessment, supporting that test expectancy positively influences long-term storage. Finally, normative data were generated according to age, sex, and education. The test, including the LTF measure, is a promising tool to estimate memory in middle-aged adults and develop predictive brain aging models.

Bidirectional within- and between-person relations between physical activity and cognitive function

OBJECTIVES

To examine bidirectional within- and between-person relations between physical activity and cognitive function across 15 years.

METHODS

Participants (N = 1722, age range 40-85 years, 55% women) were drawn from the Betula prospective cohort study. We included four waves of data. Bivariate latent curve models with structured residuals were estimated to examine bidirectional within- and between-person relations between physical activity and cognitive function (episodic memory recall, verbal fluency, visuospatial ability).

RESULTS

We observed no statistically significant bidirectional within-person relations over time. Higher levels of physical activity at baseline were related to less decline in episodic memory recall. Positive occasion-specific within- and between-person relations were observed, with the most consistent being between physical activity and episodic memory recall.

DISCUSSION

The lack of bidirectional within-person relations indicate that shorter time lags may be needed to capture time-ordered within-person relations. The link between higher physical activity at baseline and less decline in episodic memory recall over time may indicate a protective effect of physical activity on episodic memory recall.

Effects of Stress Exposure Versus Appraisal on Episodic Memory Trajectories: Evidence for Risk and Resilience Among Black Older Adults

OBJECTIVES

Chronic stressors, experienced disproportionately by Black older adults, are a risk factor for memory impairment. Racially patterned stress exposure may contribute to higher rates of Alzheimer's disease and related dementias (ADRD) among Black older adults compared with Whites, but less is known about the role of stress appraisal. This study examined whether chronic stress exposure mediates racial disparities in memory and whether stress appraisal moderates these associations.

METHODS

Participants included 16,924 older adults (Mage = 67.39, 21% Black) from the 2010 and 2012 waves of the Health and Retirement Study who completed measures of chronic stress exposure (health, financial, housing, relationships, and caregiving) and appraisal. Latent growth curves modeled longitudinal performance on a word list memory task over 6 years.

RESULTS

Black older adults reported greater stress exposure than Whites, and greater stress exposure partially mediated Black-White disparities in initial memory (standardized indirect effect = -0.002, p = .009). However, Black older adults appraised stressors as less upsetting than Whites. While stress appraisal did not moderate links between stress exposure and memory, appraising stressors as less upsetting was independently associated with better initial memory. Thus, Black-White disparities in initial memory was partially offset by Black participants' appraisal of stressors as less upsetting (standardized indirect effect = 0.002, p = .016).

DISCUSSION

Reducing chronic stress exposure may reduce racial disparities in ADRD risk. The counteractive effect of stress appraisal on Black-White disparities in episodic memory highlights resilience factors among Black older adults that should be characterized in future research to move beyond deficit models of ADRD inequality.

Ten German versions of Rey's auditory verbal learning test: Age and sex effects in 4,000 adults of the Rhineland Study

INTRODUCTION

Detecting early pathological cognitive decline is critical for dementia and aging-related research and clinical diagnostics. Rey's Auditory Verbal Learning Test (AVLT) is commonly used to measure episodic verbal memory. The test requires participants to learn a list of 15 words over several trials. Since multiple testing is often required to detect cognitive decline, but repeating the same test can bias results, we developed 10 German AVLT word lists.

METHOD

We randomly assigned the lists to 4,000 participants (aged 30-94 years) from a population-based cohort to test their comparability, as well as aging effects and sex differences.

RESULTS

Nine lists were highly comparable, with only one being slightly more difficult. Recall performance decreased on average by 0.6-1.1 words per trial per decade of age. Perseveration errors decreased with increasing age. Women remembered on average between 0.8 and 1.5 words per trial more than men, regardless of age. Women also outperformed men in the sum of Trials 1-5, learning over trials, retroactive inhibition, and false-positive and interference errors. Proactive inhibition remained stable across age and was unaffected by sex.

CONCLUSION

This German AVLT version presents comparable lists including detailed age and sex references and therefore allows test repetition excluding training effects. These versions are a valuable resource for research and clinical application.

Mediators and Moderators of the Association Between Perceived Stress and Episodic Memory in Diverse Older Adults

OBJECTIVE

Stress is a risk factor for numerous negative health outcomes, including cognitive impairment in late-life. The negative association between stress and cognition may be mediated by depressive symptoms, which separate studies have identified as both a consequence of perceived stress and a risk factor for cognitive decline. Pathways linking perceived stress, depressive symptoms, and cognition may be moderated by sociodemographics and psychosocial resources. The goal of this cross-sectional study was to identify modifying factors and enhance understanding of the mechanisms underlying the stress-cognition association in a racially and ethnically diverse sample of older adults.

METHOD

A linear regression estimated the association between perceived stress and episodic memory in 578 older adults (Mage = 74.58) in the Washington Heights-Inwood Columbia Aging Project. Subsequent models tested whether depressive symptoms mediated the stress-memory relationship and whether sociodemographics (gender, race, and ethnicity) or perceived control moderated these pathways.

RESULTS

Independent of sociodemographics and chronic diseases, greater perceived stress was associated with worse episodic memory. This relationship was mediated by more depressive symptoms. Higher perceived control buffered the association between stress and depressive symptoms. There was no significant moderation by gender, race, or ethnicity.

CONCLUSION

Depressive symptoms may play a role in the negative association between perceived stress and cognition among older adults; however, longitudinal analyses and studies using experimental designs are needed. Perceived control is a modifiable psychological resource that may offset the negative impact of stress.

Associations Between Loneliness, Reading Ability and Episodic Memory in Non-Hispanic Black and White Older Adults

OBJECTIVE

Reading ability reflects a variety of beneficial life course exposures and may better index these exposures above and beyond education in racially diverse samples. Growing evidence suggests a negative impact of perceived loneliness on late-life cognitive health when parsing out the effect of other aspects of social relations. Few studies have examined how loneliness interacts with the reading ability or whether it operates differently in Black older adults who have higher dementia risk than Whites.

METHODS

Participants in this cross-sectional study were drawn from the Washington Heights-Inwood Columbia Aging Project (n = 425 older adults, Mage = 74.23; 58% Black). Linear regressions estimated the main effects and interactions involving reading ability, loneliness, and race (non-Hispanic Black vs. non-Hispanic White) on episodic memory, controlling for age, sex/gender, and years of education. Subsequent models additionally controlled for income, employment status, depressive symptoms, disease burden, marital status, social network size, and number of social groups.

RESULTS

Higher reading ability was associated with better memory, but loneliness was not associated with memory. The positive association between reading ability and memory was weaker among individuals with greater loneliness, and this interaction did not differ by race.

CONCLUSIONS

Loneliness may suppress the protective effect of higher reading ability on cognitive health among both Black and White older adults. Future longitudinal work is needed to clarify causal relationships among loneliness, reading ability, and memory decline.

The Measurement of Everyday Cognition (ECog): Revisions and Updates

INTRODUCTION

The Everyday Cognition scale (ECog), a measure of everyday functioning developed in 2008, is sensitive to early detection and progression of neurodegenerative disease. The goal was to update ECog item content to ensure relevancy to contemporary older adults from diverse backgrounds.

METHODS

Participants included 44 culturally diverse older adults (18 with normal cognition, 11 with mild cognitive impairment) and their study partners. Item understandability and relevance was evaluated using iterative interviewing methods that were analyzed using standard qualitative methods. On the basis of this information, items were modified, deleted, or developed as needed.

RESULTS

Of the 39 original items, 19 were revised, 3 new items were added (primarily to cover contemporary activities such as the use of technology), and 1 was deleted. The revised version (ECog-II) includes 41 items.

DISCUSSION

To ensure strong psychometric properties, and to facilitate harmonization of previously collected data, we preserved well over half of the items. Future work will validate the revised ECog by measuring associations with neuropsychological performance, external measures of disease, and other functional measures. Overall, the revised ECog will continue to be a useful tool for measuring cognitively relevant everyday abilities in clinical settings and intervention clinical trials.

Hippocampal subfield volumes are associated with verbal memory after first-ever ischemic stroke

INTRODUCTION

Hippocampal subfield volumes are more closely associated with cognitive impairment than whole hippocampal volume in many diseases. Both memory and whole hippocampal volume decline after stroke. Understanding the subfields' temporal evolution could reveal valuable information about post-stroke memory.

METHODS

We sampled 120 participants (38 control, 82 stroke), with cognitive testing and 3T-MRI available at 3 months and 3 years, from the Cognition and Neocortical Volume after Stroke (CANVAS) study. Verbal memory was assessed using the Hopkins Verbal Learning Test-Revised. Subfields were delineated using FreeSurfer. We used partial Pearson's correlation to assess the associations between subfield volumes and verbal memory scores, adjusting for years of education, sex, and stroke side.

RESULTS

The left cornu ammonis areas 2/3 and hippocampal tail volumes were significantly associated with verbal memory 3-month post-stroke. At 3 years, the associations became stronger and involved more subfields.

DISCUSSION

Hippocampal subfield volumes may be a useful biomarker for post-stroke cognitive impairment.

Psychometric properties of Addenbrooke's Cognitive Examination III (ACE-III): An item response theory approach

The Addenbrooke's Cognitive Examination III is one of the most widely used tests to assess cognitive impairment. Although previous studies have shown adequate levels of diagnostic utility to detect severe impairment, it has not shown sensitivity to detect mild decline. The aim of this study was to evaluate the psychometric properties of Addenbrooke's Cognitive Examination III in a large sample of elderly people through Item Response Theory, due to the lack of studies using this approach. A cross-sectional study was conducted with 1164 people from the age of 60 upwards, of which 63 had a prior diagnosis of Alzheimer dementia. The results showed that, globally, the Addenbrooke's Cognitive Examination III possesses adequate psychometrics properties. Furthermore, the information function test shows that the subscales have different sensitivity to different levels of impairment. These results can contribute to determining patterns of cognitive deterioration for the adequate detection of different levels of dementia. An optimized version is suggested which may be an economic alternative in the applied field.

Music Engagement and Episodic Memory among Middle-Aged and Older Adults: A National Cross-Sectional Analysis

OBJECTIVES

To determine whether music engagement influences middle-aged and older adults' performance on episodic memory tasks.

METHODS

Secondary data analysis of a sample (N = 4,592) of cognitively healthy adults from the 2016 Health and Retirement Study were used for this study. Multivariable regression models were used to analyze the cross-sectional differences in performance on tasks of episodic memory between participants who listened to music (n= 3,659) or sang or played an instrument (n= 989).

RESULTS

On average, participants recalled 10.3 words out of a possible 20. Regression analyses showed that both music listening and singing or playing an instrument were independently associated with significantly better episodic memory.

DISCUSSION

The findings provide the first population-based evidence that music engagement is associated with better episodic memory among middle-aged and older adults. Future studies should examine whether the association is causal or has a dose response.

Cognitive benefits of exercise interventions: an fMRI activation likelihood estimation meta-analysis

Despite a growing number of functional MRI studies reporting exercise-induced changes during cognitive processing, a systematic determination of the underlying neurobiological pathways is currently lacking. To this end, our neuroimaging meta-analysis included 20 studies and investigated the influence of physical exercise on cognition-related functional brain activation. The overall meta-analysis encompassing all experiments revealed physical exercise-induced changes in the left parietal lobe during cognitive processing. Subgroup analysis further revealed that in the younger-age group (< 35 years old) physical exercise induced more widespread changes in the right hemisphere, whereas in the older-age group (≥ 35 years old) exercise-induced changes were restricted to the left parietal lobe. Subgroup analysis for intervention duration showed that shorter exercise interventions induced changes in regions connected with frontoparietal and default mode networks, whereas regions exhibiting effects of longer interventions connected with frontoparietal and dorsal attention networks. Our findings suggest that physical exercise interventions lead to changes in functional activation patterns primarily located in precuneus and associated with frontoparietal, dorsal attention and default mode networks.

Biological and environmental predictors of heterogeneity in neurocognitive ageing: Evidence from Betula and other longitudinal studies

Individual differences in cognitive performance increase with advancing age, reflecting marked cognitive changes in some individuals along with little or no change in others. Genetic and lifestyle factors are assumed to influence cognitive performance in ageing by affecting the magnitude and extent of age-related brain changes (i.e., brain maintenance or atrophy), as well as the ability to recruit compensatory processes. The purpose of this review is to present findings from the Betula study and other longitudinal studies, with a focus on clarifying the role of key biological and environmental factors assumed to underlie individual differences in brain and cognitive ageing. We discuss the vital importance of sampling, analytic methods, consideration of non-ignorable dropout, and related issues for valid conclusions on factors that influence healthy neurocognitive ageing.

Perceived stress and dementia: Results from the Copenhagen city heart study

Objectives: We investigated if perceived stress in midlife increased the risk of dementia. Furthermore, we explored differences between subgroups related to sex, age and employment status when reporting stress.Methods: In this longitudinal study, we used information on perceived stress from 10,814 participants (mean age 56.7 years). Participants were followed through Danish national registers for development of dementia. Participants were considered at risk of dementia from the date they turned 60 years. Perceived stress was assessed as a combination of self-reported intensity and frequency of stress, and categorized into low (score 0-1), medium (score 2-4), and high stress (score 5-6). We used Poisson regression to estimate incidence rate ratios (IRR) and their 95% confidence intervals (CI) and adjusted for sociodemographic factors and psychiatric morbidity at baseline (main model) as well as cardio/cerebrovascular diseases and health behaviors at baseline (additional model).Results: The mean follow-up time was 13.8 years, and 1,519 participants were registered with dementia. Dementia risk was higher in participants reporting medium stress (IRR = 1.11, 95% CI: 0.99-1.24) and high stress (IRR = 1.36, 95% CI: 1.13-1.65). Adjustment for cardio/cerebrovascular diseases and health behaviors did not alter the results. We did not find strong support for differences between subgroups, although the association between stress and dementia was stronger for those who were employed at the time of reporting high stress.Conclusion: Our results provide empirical support for an effect of perceived stress on the risk of dementia in old age.

Combining Cognitive Markers to Identify Individuals at Increased Dementia Risk: Influence of Modifying Factors and Time to Diagnosis

OBJECTIVE

We investigated the extent to which combining cognitive markers increases the predictive value for future dementia, when compared to individual markers. Furthermore, we examined whether predictivity of markers differed depending on a range of modifying factors and time to diagnosis.

METHOD

Neuropsychological assessment was performed for 2357 participants (60+ years) without dementia from the population-based Swedish National Study on Aging and Care in Kungsholmen. In the main sample analyses, the outcome was dementia at 6 years. In the time-to-diagnosis analyses, a subsample of 407 participants underwent cognitive testing 12, 6, and 3 years before diagnosis, with dementia diagnosis at the 12-year follow-up.

RESULTS

Category fluency was the strongest individual predictor of dementia 6 years before diagnosis [area under the curve (AUC) = .903]. The final model included tests of verbal fluency, episodic memory, and perceptual speed (AUC = .913); these three domains were found to be the most predictive across a range of different subgroups. Twelve years before diagnosis, pattern comparison (perceptual speed) was the strongest individual predictor (AUC = .686). However, models 12 years before diagnosis did not show significantly increased predictivity above that of the covariates.

CONCLUSIONS

This study shows that combining markers from different cognitive domains leads to increased accuracy in predicting future dementia 6 years later. Markers from the verbal fluency, episodic memory, and perceptual speed domains consistently showed high predictivity across subgroups stratified by age, sex, education, apolipoprotein E ϵ4 status, and dementia type. Predictivity increased closer to diagnosis and showed highest accuracy up to 6 years before a dementia diagnosis. (JINS, 2020, 00, 1-13).

Risk for Alzheimer's disease: A review of long-term episodic memory encoding and retrieval fMRI studies

Many risk factors have been identified that predict future progression to Alzheimer's disease (AD). However, clear links have yet to be made between these risk factors and how they affect brain functioning in early stages of AD. We conducted a narrative review and a quantitative analysis to better understand the relationship between nine categories of AD risk (i.e., brain pathology, genetics/family history, vascular health, head trauma, cognitive decline, engagement in daily life, late-life depression, sex/gender, and ethnoracial group) and task-evoked fMRI activity during episodic memory in cognitively-normal older adults. Our narrative review revealed widespread regional alterations of both greater and lower brain activity with AD risk. Nevertheless, our quantitative analysis revealed that a subset of studies converged on two patterns: AD risk was associated with (1) greater brain activity in frontal and parietal regions, but (2) reduced brain activity in hippocampal and occipital regions. The brain regions affected depended on the assessed memory stage (encoding or retrieval). Although the results clearly indicate that AD risks impact brain activity, we caution against using fMRI as a diagnostic tool for AD at the current time because the above consistencies were present among much variability, even among the same risk factor.

Interactive Effects of Chronic Health Conditions and Financial Hardship on Episodic Memory among Older Blacks: Findings from the Health and Retirement Study

Previous research links chronic health conditions and financial hardship to cognitive outcomes among older Blacks. However, few studies have explored the moderating effect of financial hardship on chronic disease burden and specific cognitive domains. This study examined whether financial hardship (as measured by difficulty paying monthly bills) modifies the impact of self-reported chronic health conditions (e.g., diabetes, stroke) on episodic memory among 871 older Blacks (50+ years) in the Health and Retirement Study (2006). Financial hardship modified the association between chronic disease burden and episodic memory performance such that individuals who reported very little difficulty paying their monthly bills had significantly lower memory scores at high levels of disease burden compared to those reporting high financial difficulty after controlling for age, gender and education (F 2, 49 = 5.03, p= 0.010). This cross-sectional study suggests that both financial and physical wellbeing may have joint effects on cognitive health in older Blacks.

Unique Effects of Perceived Neighborhood Physical Disorder and Social Cohesion on Episodic Memory and Semantic Fluency

OBJECTIVE

Objective measures of neighborhood quality are associated with physical and mental health outcomes for older adults, but the relationship between perceived neighborhood quality and cognitive health has not been fully explored. Furthermore, positive and negative neighborhood characteristics may influence cognition through different mechanisms. The present study aimed to determine whether perceptions of neighborhood quality predict cognitive functioning in two domains, above and beyond individual-level risk factors, in a nationally representative sample of older adults.

METHOD

Using cross-sectional weighted data from 13,919 participants aged 51 and older from the Health and Retirement Study, linear regression models tested independent associations between perceived neighborhood quality (physical disorder and social cohesion) and cognition (episodic memory and semantic verbal fluency), controlling for sociodemographic characteristics, chronic disease burden, and depressive symptoms. Interaction terms tested whether neighborhood social cohesion moderated the relationship between neighborhood physical disorder and each cognitive outcome.

RESULTS

Perception of greater neighborhood physical disorder was significantly associated with worse episodic memory, while perception of lower neighborhood social cohesion was significantly associated with worse semantic fluency. There were no significant interactions between physical disorder and social cohesion.

CONCLUSIONS

Results provide preliminary evidence for different mechanisms underlying associations between aspects of neighborhood quality and cognition (e.g., stress vs. social interaction). Additional intervention work is needed to determine whether improving neighborhood physical conditions and promoting social cohesion at the neighborhood level could reduce cognitive morbidity among older adults.

Particulate matter and episodic memory decline mediated by early neuroanatomic biomarkers of Alzheimer's disease

Evidence suggests exposure to particulate matter with aerodynamic diameter <2.5 μm (PM2.5) may increase the risk for Alzheimer's disease and related dementias. Whether PM2.5 alters brain structure and accelerates the preclinical neuropsychological processes remains unknown. Early decline of episodic memory is detectable in preclinical Alzheimer's disease. Therefore, we conducted a longitudinal study to examine whether PM2.5 affects the episodic memory decline, and also explored the potential mediating role of increased neuroanatomic risk of Alzheimer's disease associated with exposure. Participants included older females (n = 998; aged 73-87) enrolled in both the Women's Health Initiative Study of Cognitive Aging and the Women's Health Initiative Memory Study of Magnetic Resonance Imaging, with annual (1999-2010) episodic memory assessment by the California Verbal Learning Test, including measures of immediate free recall/new learning (List A Trials 1-3; List B) and delayed free recall (short- and long-delay), and up to two brain scans (MRI-1: 2005-06; MRI-2: 2009-10). Subjects were assigned Alzheimer's disease pattern similarity scores (a brain-MRI measured neuroanatomical risk for Alzheimer's disease), developed by supervised machine learning and validated with data from the Alzheimer's Disease Neuroimaging Initiative. Based on residential histories and environmental data on air monitoring and simulated atmospheric chemistry, we used a spatiotemporal model to estimate 3-year average PM2.5 exposure preceding MRI-1. In multilevel structural equation models, PM2.5 was associated with greater declines in immediate recall and new learning, but no association was found with decline in delayed-recall or composite scores. For each interquartile increment (2.81 μg/m3) of PM2.5, the annual decline rate was significantly accelerated by 19.3% [95% confidence interval (CI) = 1.9% to 36.2%] for Trials 1-3 and 14.8% (4.4% to 24.9%) for List B performance, adjusting for multiple potential confounders. Long-term PM2.5 exposure was associated with increased Alzheimer's disease pattern similarity scores, which accounted for 22.6% (95% CI: 1% to 68.9%) and 10.7% (95% CI: 1.0% to 30.3%) of the total adverse PM2.5 effects on Trials 1-3 and List B, respectively. The observed associations remained after excluding incident cases of dementia and stroke during the follow-up, or further adjusting for small-vessel ischaemic disease volumes. Our findings illustrate the continuum of PM2.5 neurotoxicity that contributes to early decline of immediate free recall/new learning at the preclinical stage, which is mediated by progressive atrophy of grey matter indicative of increased Alzheimer's disease risk, independent of cerebrovascular damage.

Longitudinal evidence that reduced hemispheric encoding/retrieval asymmetry predicts episodic-memory impairment in aging

The HERA (Hemispheric Encoding/Retrieval Asymmetry) model captures hemispheric lateralization of prefrontal cortex (PFC) brain activity during memory encoding and retrieval. Reduced HERA has been observed in cross-sectional aging studies, but there is no longitudinal evidence, to our knowledge, on age-related changes in HERA and whether maintained or reduced HERA relates to well-preserved memory functioning. In the present study we set out to explore HERA in a longitudinal neuroimaging sample from the Betula study [3 Waves over 10 years; Wave-1: n = 363, W2: n = 227, W3: n = 101]. We used fMRI data from a face-name paired-associates task to derive a HERA index. In support of the HERA model, the mean HERA index was positive across the three imaging waves. The longitudinal age-HERA relationship was highly significant (p < 10^-11), with a HERA decline occurring after age 60. The age-related HERA decline was associated with episodic memory decline (p < 0.05). Taken together, the findings provide large-scale support for the HERA model, and suggest that reduced HERA in the PFC reflects pathological memory aging possibly related to impaired ability to bias mnemonic processing according to the appropriate encoding or retrieval state.

Linear and nonlinear relationships between cognitive subdomains of ability discrepancy and Alzheimer's disease biomarkers

OBJECTIVE

Substantial research indicates that fluid and crystallized abilities are highly correlated throughout the adult life span. However, recent proposals suggest that a large discrepancy between these two abilities, defined as crystallized performance minus fluid performance, indicates heightened risk for Alzheimer's disease (AD).

METHOD

In 266 cognitively healthy older adults, the present study tested linear and quadratic relationships between an ability discrepancy score and early AD neuropathology indexed via in vivo measures of beta-amyloid deposition and cortical thickness in AD-vulnerable regions. We also tested the extent that alternative forms of this ability discrepancy measure (e.g., subdomain discrepancies, verbal-visual discrepancies) and an episodic memory composite might also be sensitive markers of early AD pathology.

RESULTS

An overall ability discrepancy was linearly and positively correlated with beta- amyloid. A quadratic relationship was found between the overall ability discrepancy score and cortical thickness such that a small positive correlation was found at lower discrepancy levels (fluid > crystallized), but at higher discrepancy levels (crystallized > fluid) a negative relationship was found (i.e., an inverted-U pattern). Similar patterns were found across each subdomain of cognition, but the effects were weaker than the overall ability discrepancy score. Importantly, inclusion of episodic memory (the gold standard) did not alter any of the effects, suggesting that an ability discrepancy confers unique predictiveness of AD biomarkers.

CONCLUSIONS

These findings replicate previous findings and increase the confidence in their usefulness to predict AD biomarkers. Longitudinal validation is needed to clearly relate an ability discrepancy to specific stages of preclinical AD. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Anatomic and neuropsychological findings in low-educated cognitively intact elderly from a Brazilian cohort

In elderly individuals, low educational level may represent a risk factor for the development of dementia and a proxy of cognitive reserve. Objective: This study examined the cognitive and neuroanatomic correlates of high versus low educational levels in cognitively healthy community-dwelling older adults in Brazil. Methods: Fifty-three older adults (mean age: 68±5.3 years) were divided into a “low education” group [LE; 1-4 years of education (N=33)] and “high education” group [HE; >11 years of education (N=20)]. Both groups completed a comprehensive neuropsychological battery and underwent in vivo structural MRI close to the time of testing. Results: Higher educational level increased the chance of having better scores on neuropsychological tests, including verbal and visual delayed recall of information, verbal learning, category fluency, global cognition, and vocabulary. Better scores on these tests were observed in the HE group relative to the LE group. Despite this, there were no group differences between MRI measures. Conclusion: Older adults with higher educational levels showed better scores on neuropsychological measures of cognition, highlighting the need for education-adjusted norms in developing countries. Given the absence of differences in structural anatomy between the groups, these findings appear to be best explained by theories of cognitive reserve.

Relationships between Physical Activity, Sedentary Behaviour and Cognitive Functions in Office Workers

Increasing evidence from animal experiments suggests that physical activity (PA) promotes neuroplasticity and learning. For humans, most research on the relationship between PA, sedentary behaviour (SB), and cognitive function has relied on self-reported measures of behaviour. Office work is characterised by high durations of SB combined with high work demands. While previous studies have shown that fitter office workers outperform their less fit colleagues in cognitive tests, the importance of PA and SB remains unknown. This study investigated associations between objectively measured PA and SB, using hip-worn accelerometers, and cognitive functions in 334 office workers. Time spent in moderate-to-vigorous PA (MVPA) was not associated with any cognitive outcome. However, time spent in SB tended to be positively associated with words recalled in free recall (β = 0.125). For the least fit participants, the average length of MVPA bouts was favourably related to Stroop performance (β = -0.211), while for the fitter individuals, a longer average length of MVPA bouts was related to worse recognition (β = -0.216). While our findings indicate that the length of MVPA bouts was associated with better Stroop performance in the least fit participants, our findings do not support the notion that more time spent in MVPA or less time in SB is associated with better cognitive function.

Memory profiles predict dementia over 23-28 years in normal but not successful aging

OBJECTIVES

Prospective studies suggest that memory deficits are detectable decades before clinical symptoms of dementia emerge. However, individual differences in long-term memory trajectories prior to diagnosis need to be further elucidated. The aim of the current study was to investigate long-term dementia and mortality risk for individuals with different memory trajectory profiles in a well-characterized population-based sample.

METHODS

1062 adults (aged 45-80 years) who were non-demented at baseline were followed over 23-28 years. Dementia and mortality risk were studied for three previously classified episodic memory trajectory groups: maintained high performance (Maintainers; 26%), average decline (Averages; 64%), and accelerated decline (Decliners; 12%), using multistate modeling to characterize individuals' transitions from an initial non-demented state, possibly to a state of dementia and/or death.

RESULTS

The memory groups showed considerable intergroup variability in memory profiles, starting 10-15 years prior to dementia diagnosis, and prior to death. A strong relationship between memory trajectory group and dementia risk was found. Specifically, Decliners had more than a fourfold risk of developing dementia compared to Averages. In contrast, Maintainers had a 2.6 times decreased dementia risk compared to Averages, and in addition showed no detectable memory decline prior to dementia diagnosis. A similar pattern of association was found for the memory groups and mortality risk, although only among non-demented.

CONCLUSION

There was a strong relationship between accelerated memory decline and dementia, further supporting the prognostic value of memory decline. The intergroup differences, however, suggest that mechanisms involved in successful memory aging may delay symptom onset.

Life course biopsychosocial effects of retrospective childhood social support and later-life cognition

Social support during childhood lays the foundation for social relationships throughout the life course and has been shown to predict a wide range of mental and physical health outcomes. Social support measured in late life is prospectively associated with better cognitive aging, but few studies have evaluated social support received earlier in the life course. We quantified the effects of childhood social support, reported retrospectively, on later-life cognitive trajectories and investigated biopsychosocial mechanisms underlying these associations. Latent growth curve models estimated 10-year cognitive trajectories in 8,538 participants (baseline ages 45-93; Mage = 63) in the REasons for Geographic And Racial Differences in Stroke (REGARDS) project. Independent of sociodemographics, childhood socioeconomic status, and household size, greater retrospective childhood social support was associated with better initial episodic memory, but not verbal fluency or cognitive change, in later adulthood. Associations with initial memory level were mediated by sociodemographic and psychosocial variables; specifically, those who reported greater childhood social support reported higher educational attainment and had better physical and emotional health in adulthood, which were each associated with better memory. These results provide support for broad and enduring effects of childhood social support on mental, physical, and cognitive health decades later. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Longitudinal socioemotional pathways between retrospective early life maternal relationship quality and episodic memory in older adulthood

Prior research suggests that social relations may play a role in explaining individual differences in cognitive functioning in older adulthood. In particular, early life maternal relationship quality (MRQ) has been shown to be a strong predictor of later-life socioemotional outcomes and may also contribute to later-life cognitive outcomes. The current study aimed to examine longitudinal associations between retrospective early life MRQ and later-life episodic memory directly and indirectly through socioemotional pathways. Three waves of data spanning 6 years of the Health and Retirement Study were used (T1: 2008, T2: 2012, T3: 2014; n = 5,263, Mage = 69.31, SD = 10.75 at T1). A longitudinal mediation model tested the direct and indirect effects of retrospectively reported MRQ at T1 on T2 memory and latent change in memory from T2 to T3 through depressive symptoms, social network size, and loneliness at T2. Analyses revealed that better MRQ at T1 was associated with less loneliness and fewer depressive symptoms at T2, and in turn, each was independently associated with less decline in memory from T2 to T3. Overall, findings suggest an enduring effect of early life social experiences on later-life cognitive functioning through socioemotional pathways. These findings further highlight the necessity of taking an integrative and life course perspective when examining the relationship between social relations and cognition. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Frontal Contribution to Hippocampal Hyperactivity During Memory Encoding in Aging

Hippocampal hypo- as well as hyper-activation have been reported during memory encoding in older individuals. Prefrontal cortex (PFC) provides top-down state signals to the hippocampus that bias its computation during memory encoding and retrieval, and disturbed top-down signals could contribute to hippocampal hyper-activation. Here, we used >500 cross-sectional and longitudinal observations from a face-name encoding-retrieval fMRI task to examine hippocampal hypo- and hyper-activation in aging. Age-related anterior hippocampal hypo-activation was observed during memory encoding. Next, older individuals who longitudinally dropped-out were compared with those who remained in the study. Older dropouts had lower memory performance and higher dementia risk, and hyper-activated right anterior and posterior hippocampus during memory encoding. During encoding, the dropouts also activated right prefrontal regions that instead were active during retrieval in younger and older remainers. Moreover, the dropouts showed altered frontal-hippocampal functional connectivity, notably elevated right PFC to anterior hippocampus (aHC) connectivity during encoding. In the context of a general pattern of age-related anterior hippocampal hypo-activation during encoding, these findings support a top-down contribution to paradoxically high anterior hippocampal activity in older dropouts who were at elevated risk of pathology.

The Enduring Effects of Mother-Child Interactions on Episodic Memory in Adulthood

OBJECTIVE

To examine the enduring effects of retrospective reports of early life mother-child interactions on psychosocial and cognitive functioning later in life.

BACKGROUND

Mother-child interactions have been linked to cognitive outcomes in childhood, however, little work has examined whether early life mother-child interactions have far-reaching effects on episodic memory in adulthood. Early life mother-child interactions may also influence cognitive functioning in adulthood indirectly through the development of academic competence (education attainment), social competence (marital satisfaction, social support, contact frequency), and/or depressive symptoms.

METHODS

Using longitudinal data from the Wisconsin Longitudinal Study sibling respondents (1993-2011; baseline: 29-79 years), we examined how retrospective positive mother-child interactions (PMCI) and negative mother-child interactions (NMCI) were independently associated with episodic memory. Structural equation modeling was used to model direct and indirect pathways from PMCI and NMCI to episodic memory and latent change in episodic memory.

RESULTS

More PMCI retrospectively reported at T1 were associated with higher T2 memory and less memory decline from T2 to T3 via higher education. Additionally, more PMCI were associated with higher T2 memory through greater marital satisfaction. Independent of these indirect effects, more PMCI and NMCI were each associated with higher T2 memory, but not memory change.

CONCLUSION

Mother-child interactions appeared to have an enduring effect on episodic memory in adulthood. These findings highlight the importance of taking a more integrative and lifespan perspective to assess how early life experiences affect socioemotional and cognitive development.

Combining Cognitive, Genetic, and Structural Neuroimaging Markers to Identify Individuals with Increased Dementia Risk

Background:

Cognitive and biological markers have shown varying degrees of success in identifying persons who will develop dementia.

Objective: To evaluate different combinations of cognitive and biological markers and identify prediction models with the highest accuracy for identifying persons with increased dementia risk.

Methods:

Neuropsychological assessment, genetic testing (apolipoprotein E –APOE), and structural magnetic resonance imaging (MRI) were performed for 418 older individuals without dementia (60–97 years) from a population-based study (SNAC-K). Participants were followed for six years.

Results:

Cognitive, genetic, and MRI markers were systematically combined to create prediction models for dementia at six years. The most predictive individual markers were perceptual speed or carrying at least one APOEɛ4 allele (AUC = 0.875). The most predictive model (AUC = 0.924) included variables from all three modalities (category fluency, general knowledge, any ɛ4 allele, hippocampal volume, white matter-hyperintensity volume).

Conclusion:

This study shows that combining markers within and between modalities leads to increased predictivity for future dementia. However, minor increases in predictive value should be weighed against the cost of additional tests in larger-scale screening.

Age-Related Differences With Immersive and Non-immersive Virtual Reality in Memory Assessment

Memory decline associated with physiological aging and age-related neurological disorders has a direct impact on quality of life for seniors. With demographic aging, the assessment of cognitive functions is gaining importance, as early diagnosis can lead to more effective cognitive interventions. In comparison to classic paper-and-pencil approaches, virtual reality (VR) could offer an ecologically valid environment for assessment and remediation of cognitive deficits. Despite the rapid development and application of new technologies, the results of studies aimed at the role of VR immersion in assessing cognitive performance and the use of VR in aging populations are often ambiguous. VR can be presented in a less immersive form, with a desktop platform, or with more advanced technologies like head-mounted displays (HMDs). Both these VR platforms are associated with certain advantages and disadvantages. In this study, we investigated age-related differences related to the use of desktop and HMD platforms during memory assessment using an intra-subject design. Groups of seniors (N = 36) and young adults (N = 25) completed a virtual Supermarket Shopping task using desktop and HMD platforms in a counterbalanced order. Our results show that the senior performances were superior when using the non-immersive desktop platform. The ability to recall a shopping list in the young adult group remained stable regardless of the platform used. With the HMD platform, the performance of the subjects of both groups seemed to be more influenced by fatigue. The evaluated user experiences did not differ between the two platforms, and only minimal and rare side effects were reported by seniors. This implies that highly immersive technology has good acceptance among aging adults. These findings might have implications for the further use of HMD in cognitive assessment and remediation.

Serum Metabolite Markers of Dementia Through Quantitative NMR Analysis: The Importance of Threonine-Linked Metabolic Pathways

There is a great need for diagnostic biomarkers of impending dementia. Metabolite markers in blood have been investigated in several studies, but inconclusive findings encourage further investigation, particularly in the pre-diagnostic phase. In the present study, the serum metabolomes of 110 dementia or pre-diagnostic dementia individuals and 201 healthy individuals matched for age, gender, and education were analyzed by nuclear magnetic resonance spectroscopy in combination with multivariate data analysis. 58 metabolites were quantified in each of the 311 samples. Individuals with dementia were discriminated from controls using a panel of seven metabolites, while the pre-diagnostic dementia subjects were distinguished from controls using a separate set of seven metabolites, where threonine was a common significant metabolite in both panels. Metabolite and pathway alterations specific for dementia and pre-diagnostic dementia were identified, in particular a disturbed threonine catabolism at the pre-diagnostic stage that extends to several threonine-linked pathways at the dementia stage.

School Performance and Educational Attainment as Early-Life Predictors of Age-Related Memory Decline: Protective Influences in Later-Born Cohorts

Objectives

Evidence is accumulating that early-life characteristics and experiences contribute significantly to differences in cognitive aging. This study investigated whether school performance at age 12 predicted late-life level and rate of memory change over 15–25 years, and whether its potential protective influence on memory change was mediated by educational attainment or income.

Methods

Latent growth curve models were fitted to 15–25 year longitudinal memory data from a population-based sample, stratified on age cohorts (n = 227, born 1909–1935; n = 301, born 1938–1954).

Results

A latent-level school grade variable significantly predicted both memory level and slope in later-born cohorts. Higher grades were associated with higher level and reduced decline, measured between ages 45 and 70 years, on average. In the earlier-born cohorts, grades predicted memory level, but not slope, measured between ages 66 and 81 years. Follow-up analyses indicated that the protective influence of higher school grades in later-born cohorts was partially mediated by educational attainment, but independent of income.

Discussion

The results suggest that higher childhood school performance is protective against age-related cognitive decline in younger or later-born cohorts, for which further education has been more accessible. Education may exert such influence through increased cognitive reserve or more well-informed health- and lifestyle decisions.

Road traffic noise, air pollution, and risk of dementia - results from the Betula project

BACKGROUND

There is growing evidence for a negative impact of traffic-related air pollution on risk of dementia. However, the contribution of noise exposure to this association has been rarely examined.

OBJECTIVE

We aimed to investigate the individual and combined effect of noise and air pollution on risk of dementia.

METHODS

Data on dementia incidence over a 15 year period was obtained from the Betula project, a longitudinal study on health and ageing. Estimates of annual mean levels of nitrogen oxides (NO_x) at the participants' residential address were obtained using a land-use regression model. Modelled data provided road traffic noise levels (Leq. 24 h) at the participants' residential address at baseline. Cox proportional hazard regression was used to calculate hazard ratios (HR).

RESULTS

Of 1721 participants at baseline, 302 developed dementia during the follow up period. Exposure to noise levels (Leq. 24 h) > 55 dB had no significant effect on dementia risk (HR 0.95; CI: 0.57, 1.57). Residing in the two highest quartiles of NO_x exposure was associated with an increased risk of dementia. The risk associated with NO_x was not modified by adjusting for noise. Moreover, we found no significant interaction effects between NO_x and road traffic noise on dementia risk.

CONCLUSION

We found no evidence that exposure to road traffic noise, either independently or in combination with traffic air pollution, was associated with risk of dementia in our study area. Our results suggest that pollution should be considered the main component in the association between traffic related exposures and dementia.

Association between air pollution from residential wood burning and dementia incidence in a longitudinal study in Northern Sweden

Objectives

There is highly suggestive evidence for an effect of air pollution exposure on dementia-related outcomes, but evidence is not yet present to clearly pinpoint which pollutants are the probable causal agents. The aims of this study was to assess the longitudinal association between exposures of fine ambient particulate matter (PM_2.5) from residential wood burning, and vehicle exhaust, with dementia.

Method

We used data from the Betula study, a longitudinal study of dementia in Umeå, Northern Sweden. The study size was 1 806 and the participants were followed from study entry (1993–1995) to 2010. Modelled levels of source-specific fine particulate matter at the residential address were combined with information on wood stoves or wood boilers, and with validated data on dementia diagnosis and individual-level characteristics from the Betula study. Cox proportional hazards models were used to estimate Hazard Ratios (HRs) and their 95% CIs for dementia incidence (vascular dementia and Alzheimer’s disease), adjusted for individual-level characteristics.

Results

The emission of PM_2.5 from local residential wood burning was associated with dementia incidence with a hazard ratio of 1.55 for a 1 μg/m³ increase in PM_2.5 (95% Confidence Interval (CI): 1.00–2.41, p-value 0.05). Study participants with an address in an area with the highest quartile of PM_2.5 from residential wood burning and who also had a wood-burning stove were more likely to develop dementia than those in the lower three quartiles without a wood-burning stove with hazard ratios of 1.74 (CI: 1.10–2.75, p-value 0.018). Particulate matter from traffic exhaust seemed to be associated with dementia incidence with hazard ratios of 1.66, (CI: 1.16–2.39), p-value 0.006, and 1.41 (CI: 0.97–2.23), p-value 0.07, in the third and fourth quartiles, respectively.

Conclusions

If the associations we observed are causal, then air pollution from residential wood burning, and air pollution from traffic, might be independent important risk factors for dementia.

False Memories in Alzheimer's Disease: Intact Semantic Priming But Impaired Production of Critical Lures

Objectives

This study explores the activation of the critical lure (CL) and its production in Deese-Roediger-McDermott (DRM) tasks in Alzheimer's disease and aging. In a previous lexical decision task including DRM lists, we showed that the activation of the CL occurs normally in Alzheimer's patients. Here, we reproduce this study and add a production (DRM) task in order to compare both processes in the same groups of participants.

Method

Eighteen older adults and 20 Alzheimer's patients performed a conventional DRM task, followed by a lexical decision task with DRM lists intermixed with neutral words and nonwords.

Results

Analyses indicated that Alzheimer's patients produced significantly fewer CLs than older participants in the DRM task, but that they showed, like older adults, shorter lexical decision latencies for CLs than for other types of words.

Discussion

This study provides evidence that the low production of CLs regularly documented in Alzheimer's patients in the DRM paradigm is not necessarily explained by their nonactivation. The results are discussed in the light of the hypothesis of a rapid disappearance of the episodic mnemonic trace of the CLs in Alzheimer's patients.

Neuropsychological Testing and Machine Learning Distinguish Alzheimer's Disease from Other Causes for Cognitive Impairment

With promising results in recent treatment trials for Alzheimer’s disease (AD), it becomes increasingly important to distinguish AD at early stages from other causes for cognitive impairment. However, existing diagnostic methods are either invasive (lumbar punctures, PET) or inaccurate Magnetic Resonance Imaging (MRI). This study investigates the potential of neuropsychological testing (NPT) to specifically identify those patients with possible AD among a sample of 158 patients with Mild Cognitive Impairment (MCI) or dementia for various causes. Patients were divided into an early stage and a late stage group according to their Mini Mental State Examination (MMSE) score and labeled as AD or non-AD patients based on a post-mortem validated threshold of the ratio between total tau and beta amyloid in the cerebrospinal fluid (CSF; Total tau/Aβ(1–42) ratio, TB ratio). All patients completed the established Consortium to Establish a Registry for Alzheimer’s Disease—Neuropsychological Assessment Battery (CERAD-NAB) test battery and two additional newly-developed neuropsychological tests (recollection and verbal comprehension) that aimed at carving out specific Alzheimer-typical deficits. Based on these test results, an underlying AD (pathologically increased TB ratio) was predicted with a machine learning algorithm. To this end, the algorithm was trained in each case on all patients except the one to predict (leave-one-out validation). In the total group, 82% of the patients could be correctly identified as AD or non-AD. In the early group with small general cognitive impairment, classification accuracy was increased to 89%. NPT thus seems to be capable of discriminating between AD patients and patients with cognitive impairment due to other neurodegenerative or vascular causes with a high accuracy, and may be used for screening in clinical routine and drug studies, especially in the early course of this disease.

Smell Loss Predicts Mortality Risk Regardless of Dementia Conversion

OBJECTIVES

To determine whether dementia could explain the association between poor olfactory performance and mortality risk within a decade-long follow-up period.

DESIGN

Prospective cohort study.

SETTING

Betula Study, Umeå, Sweden.

PARTICIPANTS

A population-based sample of adult participants without dementia at baseline aged 40 to 90 (N = 1,774).

MEASUREMENTS

Olfactory performance using the Scandinavian Odor-Identification Test (SOIT) and self-reported olfactory function; several social, cognitive, and medical risk factors at baseline; and incident dementia during the following decade.

RESULTS

Within the 10-year follow-up, 411 of 1,774 (23.2%) participants had died. In a Cox model, the association between higher SOIT score and lower mortality was significant (hazard ratio (HR) = 0.74 per point interval, 95% confidence interval (CI) = 0.71-0.77, P < .001). The effect was attenuated, but remained significant, after controlling for age, sex, education, and health-related and cognitive variables (HR = 0.92, 95% CI = 0.87-0.97, P = .001). The association between SOIT score and mortality was retained after controlling for dementia conversion before death (HR = 0.92, 95% CI = 0.87-0.97, P = .001). Similar results were obtained for self-reported olfactory dysfunction.

CONCLUSION

Poor odor identification and poor self-reported olfactory function are associated with greater likelihood of future mortality. Dementia does not attenuate the association between olfactory loss and mortality, suggesting that olfactory loss might mark deteriorating health, irrespective of dementia.