Personality and Alzheimer's disease: An integrative review

High-frequency assessment of mood, personality, and cognition in healthy younger, healthy older and adults with cognitive impairment

Increased variability in cognitive scores, mood or personality traits can be indicative of underlying neurological disorders. Whether variability in cognition is due to changes in mood or personality is unknown. A total of 66 younger adults, 51 healthy older adults and 38 participants with cognitive impairment completed 21 daily sessions of attention, working memory, mood, and personality assessment. Group differences in mean performance and variability were examined using Bayesian mixed effects location scale models. Variability in attention decreased from younger to older adults and then increased again in cognitive impairment. Younger adults were more variable in agreeableness, openness and conscientiousness compared to older adults. The clinically impaired group differed from the healthy older adults in terms of variability on attention, openness, and conscientiousness. Healthy aging results in greater stability in personality traits over short intervals yet this stability is not redundant with increased stability in cognitive scores.

Does personality affect the cognitive decline in aging? A systematic review

Cognitive decline is a natural consequence of aging, but several genetic, environmental, and psychological factors can influence its trajectories. Among the most enduring factors, the Big Five personality traits - defined as relatively stable tendencies to think, behave, and react to the environment - can influence both directly (e.g., by physiological correlates) and indirectly (e.g., healthy or risky behaviors) the risk of developing dementia and mild cognitive impairment (MCI) - a preclinical form of cognitive decline. Despite the great amount of studies focusing on the relationship between personality and cognitive decline, an updated systematic synthesis of the results including a broader range of study designs is still lacking. This systematic review aims to summarize the findings of studies investigating: (i) differences in personality traits between groups of healthy individuals and those with MCI, (ii) the impact of personality traits on the risk for both MCI and dementia, and (iii) changes in personality traits among individuals progressing from normal cognition to MCI. Neuroticism emerged as a significant risk factor for MCI and dementia; Conscientiousness and Openness appear to offer protection against dementia and moderate cognitive decline. Overall, these findings suggest a pivotal role of personality structure in shaping cognitive outcomes on the long run.

Personality and Transition From Mild Cognitive Impairment to Normal Cognition vs Dementia

OBJECTIVES

Mild cognitive impairment (MCI) is a critical stage preceding incident dementia, but not all individuals with MCI progress to dementia and some revert to normal cognition. This study examined whether personality is associated with the probability of transition from MCI to normal cognition or dementia.

DESIGN

Longitudinal observational study.

SETTING AND PARTICIPANTS

Older adults with MCI from the Health and Retirement Study (N = 1608, 56% female, mean age = 72.29, SD = 9.91). Personality traits; cognitive status; and demographic (age, sex, education, race, and ethnicity), clinical (diabetes, hypertension), behavioral (smoking, physical activity), psychological (depressive symptoms), and genetic (apolipoprotein E ε4) covariates were obtained in 2006/2008. Follow-up data on cognitive status were collected every 2 years up to the 2020 wave.

METHODS

Cox regression analyses tested the association between personality and reversion from MCI to normal cognition and progression to dementia, controlling for demographic, clinical, behavioral, psychological, and genetic covariates.

RESULTS

Controlling for demographic factors, lower neuroticism and higher openness and conscientiousness were associated with a higher likelihood of reversion from MCI to normal cognition and a lower risk of progression to dementia over time. Higher agreeableness was related to a lower risk of progression to dementia. Clinical, behavioral, psychological, and genetic factors partially accounted for these associations. There was little evidence that demographic, genetic factors, or baseline cognition moderated these associations.

CONCLUSIONS AND IMPLICATIONS

Personality traits can help identify individuals who are more likely to revert from MCI and not progress to dementia. These findings suggest that even during mild impairment, personality may modulate dementia risk and thus inform targeted interventions.

Personality traits moderate associations between word recall and subjective memory

Cognitive gerontology research requires consideration of performance as well as perceptions of performance. While subjective memory is positively associated with memory performance, these correlations typically are modest in magnitude, leading to the need to consider whether certain people may show weaker or stronger linkages between performance and perceptions. The current study leveraged personality (NEO Big Five), memory performance (i.e., word recall), and perceptions of memory ability (i.e., metamemory in adulthood and memory decline) data from the St. Louis Personality and Aging Network (SPAN) study (n = 774, mean age: 71.52 years). Extraversion and conscientiousness held the most consistent associations with the cognitive variables of interest, as both traits were positively associated with metamemory and word recall, but negatively associated with subjective decline. Moreover, extraversion moderated associations between word recall and both memory capacity and complaints, insofar that objective-subjective associations were weaker for those adults higher in extraversion. These findings highlight the need to understand how personality influences the sources of information employed for subjective cognitive beliefs.

Does social connection mediate the association between neuroticism and cognition? Cross-sectional analysis of the Canadian Longitudinal Study on Aging

OBJECTIVES

This study tested the association between neuroticism and six cognitive measures, and examined the potential mediating roles of social connection (social isolation and loneliness) among middle-aged and older adults.

METHODS

This cross-sectional study was a secondary analysis of the Canadian Longitudinal Study on Aging (CLSA) Comprehensive Cohort, a sample of Canadians aged 45-85 years at baseline. Respondents with data collected at the first follow-up, between 2015 and 2018, were included (n = 27,765). Structural equation modelling was used to assess the association between neuroticism and six cognitive measures (Rey Auditory Verbal Learning Test immediate recall and delayed recall, Animal Fluency Test, Mental Alternation Test, Controlled Oral Word Association Test and Stroop Test interference ratio), with direct and indirect effects (through social isolation and loneliness). All analyses were stratified by sex, including females (n = 14,133) and males (n = 13,632).

RESULTS

In unadjusted models, there was evidence of associations between neuroticism and all cognitive measures, except the Stroop Test interference ratio, suggesting higher neuroticism was associated with lower scores on memory and executive function tests. In the models of these other five outcomes, there was consistent evidence of indirect effects (through social isolation and loneliness) and, in some cases, direct effects. The results are discussed in context with limitations, including the use of cross-sectional design and alternative hypotheses to explain the association between personality and cognition.

CONCLUSION

Among middle-aged and older adults, for both males and females, the findings suggest that the association between neuroticism and cognitive outcomes may be mediated by aspects of social connection.

Association of personality facets and cognition in the Lifelines population-based cohort study

BACKGROUND

Personality traits have been associated with cognitive functioning and risk of cognitive decline. Fewer studies have investigated how personality facets are associated with cognition in large cohorts with a prospective design.

METHODS

The association between eight personality facets and cognition (speed measures reflecting psychomotor speed and visual attention; hit rate measures reflecting visual learning and working memory) was analyzed in middle-aged adults from the Lifelines cohort (N = 79911; age 43 ± 11 years).

RESULTS

High hostility, high vulnerability, low excitement seeking, and low competence were associated with worse cognitive performance on all tasks. Impulsivity-related facets had weak and differential associations, with self-discipline negatively associated with accuracy and deliberation negatively associated with speed. These associations remained largely unchanged when accounting for lifestyle factors (smoking, alcohol consumption, physical activity). The associations with cognition were stronger in older people for impulsiveness, deliberation, and hostility, while stronger in younger people for excitement seeking, self-discipline, and vulnerability.

CONCLUSION

In a large population-based sample with a broad age range, the associations of personality facets with cognitive functioning had small effect sizes, were independent of lifestyle factors, and varied with age and among facets within the same personality domain. These findings highlight the importance of developmental stages and facet-level research in personality-cognition associations.

Are trajectories of personality and socioeconomic factors prospectively associated with midlife cognitive function? Findings from a 12-year longitudinal study of Mexican-origin adults

Problems with memory, executive function, and language are a significant public health concern, especially when they begin during midlife. However, there is relatively little work on risk and protective factors for cognitive function in middle adulthood. Using data from 883 Mexican-origin adults assessed up to 6 times across 12 years (Mage at Time 1 = 38.2 years; range = 27-63 years), the present study examined whether developmental trajectories (levels and slopes) of Big Five personality domains and socioeconomic factors (per capita income, economic stress) were prospectively associated with cognitive function (memory, mental status, verbal fluency) at the final assessment. We found that individuals with higher levels of, and smaller decreases in, Neuroticism had worse cognitive function 12 years later. Further, individuals with higher initial Conscientiousness had better subsequent memory, mental status, and verbal fluency, and individuals with higher Openness and Extraversion had better subsequent verbal fluency (but not memory or mental status). The trajectories of per capita income and economic stress were robustly associated with cognitive function, such that higher initial levels and greater increases in socioeconomic resources had protective associations, whereas higher levels and greater increases in economic stress had deleterious associations with cognitive function. Higher education level was associated with better cognitive function 12 years later. These findings suggest that changes in personality and socioeconomic factors across adulthood are associated with cognitive function, which may be informative for interventions to support healthier cognitive aging starting at least as early as midlife. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Informant-rated change in personality traits, psychological distress, well-being, and social connection with dementia

OBJECTIVES

Studies of retrospective personality change with dementia consistently find caregivers report large changes in personality (e.g., increases in neuroticism) of their care recipients compared to before dementia. This work seeks to replicate the established pattern of personality change, extend it to change in psychological distress, well-being, and social connection, and evaluate whether changes vary by stage of dementia.

METHODS

Caregivers of people with dementia (N = 188) reported on the psychological and social health of their care recipient currently and how they were before they developed dementia. Personality was measured as five factor model traits. Psychological distress was measured as symptoms of depression and anxiety, perceived stress, and pessimism. Psychological well-being was measured as purpose in life, life satisfaction, happiness, self-efficacy, and optimism. Social connection was measured as loneliness, belonging, social support, and social strain.

RESULTS

There were substantial increases in neuroticism (d = 1.14) and decreases in the other four personality traits (d range=-0.85 to -1.37). There were significant increases in psychological distress (e.g., d = 1.07 for depression) and substantial decreases in well-being (e.g., d=-1.18 for purpose in life) and social connection (e.g., d=-1.12 for belonging). Change was apparent across dementia stage and generally larger in more severe dementia.

DISCUSSION

In addition to personality, there are large retrospective changes in psychological distress, well-being, and social connection with dementia. These quantitative findings complement clinical observations of the natural history of psychosocial changes in people with dementia, and can inform families, clinicians, and researchers on commonly observed changes and improve interventions to mitigate dementia burden.

Bacopa monnieri: A promising herbal approach for neurodegenerative disease treatment supported by in silico and in vitro research

Neurodegenerative disorders, caused by progressive neuron loss, are a global health issue. Among the various factors implicated in their pathogenesis, dysregulation of acetylcholinesterase activity has been recognized as a key contributor. Acetylcholinesterase breaks down the neurotransmitter acetylcholine, important for neural transmission. Evaluating phyto-compounds from Bacopa monnieri Linn. through in vitro and in silico analysis may expand their role as alternative therapeutic agents by modulating the function of acetylcholinesterase and complementing existing treatments. To accomplish this objective, chemical structures of phyto-compounds were retrieved from PubChem database and subjected to in silico and in vitro approaches. Virtual screening was performed through molecular docking and molecular dynamic simulation resulting in four top hit compounds including quercetin, apigenin, wogonin, and bacopaside X (novel lead compound for acetylcholinesterase inhibitor) with least binding score. Further, dose dependent acetylcholinesterase inhibition biochemical assay depicted that bacopaside X, apigenin, quercetin, and wogonin exhibited strong potential against acetylcholinesterase with IC50 values of 12.78 μM, 13.83 μM, 12.73 μM and 15.48 μM respectively, in comparison with the donepezil (IC50: 0.0204 μM). The in silico and in vitro research suggests that B. monnieri phyto-compounds have the potential to modulate molecular targets associated with neurodegenerative diseases and have a role in neuroprotection.

Circular-SWAT for deep learning based diagnostic classification of Alzheimer's disease: application to metabolome data

BACKGROUND

Deep learning has shown potential in various scientific domains but faces challenges when applied to complex, high-dimensional multi-omics data. Alzheimer's Disease (AD) is a neurodegenerative disorder that lacks targeted therapeutic options. This study introduces the Circular-Sliding Window Association Test (c-SWAT) to improve the classification accuracy in predicting AD using serum-based metabolomics data, specifically lipidomics.

METHODS

The c-SWAT methodology builds upon the existing Sliding Window Association Test (SWAT) and utilizes a three-step approach: feature correlation analysis, feature selection, and classification. Data from 997 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) served as the basis for model training and validation. Feature correlations were analyzed using Weighted Gene Co-expression Network Analysis (WGCNA), and Convolutional Neural Networks (CNN) were employed for feature selection. Random Forest was used for the final classification.

FINDINGS

The application of c-SWAT resulted in a classification accuracy of up to 80.8% and an AUC of 0.808 for distinguishing AD from cognitively normal older adults. This marks a 9.4% improvement in accuracy and a 0.169 increase in AUC compared to methods without c-SWAT. These results were statistically significant, with a p-value of 1.04 × 10ˆ-4. The approach also identified key lipids associated with AD, such as Cer(d16:1/22:0) and PI(37:6).

INTERPRETATION

Our results indicate that c-SWAT is effective in improving classification accuracy and in identifying potential lipid biomarkers for AD. These identified lipids offer new avenues for understanding AD and warrant further investigation.

FUNDING

The specific funding of this article is provided in the acknowledgements section.

Changes in Personality Before and During Cognitive Impairment

OBJECTIVES

Clinical observations and studies of retrospective observer ratings point to changes in personality in persons with cognitive impairment or dementia. The timing and magnitude of such changes, however, are unclear. This study used prospective self-reported data to examine the trajectories of personality traits before and during cognitive impairment.

DESIGN

Longitudinal observational cohort study.

SETTING AND PARTICIPANTS

Older adults from the United States in the Health and Retirement Study were assessed for cognitive impairment and completed a measure of the 5 major personality traits every 4 years from 2006 to 2020 (N = 22,611; n = 5507 with cognitive impairment; 50,786 personality and cognitive assessments).

METHODS

Multilevel modeling examined changes before and during cognitive impairment, accounting for demographic differences and normative age-related trajectories.

RESULTS

Before cognitive impairment was detected, extraversion (b = -0.10, SE = 0.02), agreeableness (b = -0.11, SE = 0.02), and conscientiousness (b = -0.12, SE = 0.02) decreased slightly; there was no significant change in neuroticism (b = 0.04, SE = 0.02) or openness (b = -0.06, SE = 0.02). During cognitive impairment, faster rates of change were found for all 5 personality traits: neuroticism (b = 0.10, SE = 0.03) increased, and extraversion (b = -0.14, SE = 0.03), openness (b = -0.15, SE = 0.03), agreeableness (b = -0.35, SE = 0.03), and conscientiousness (b = -0.34, SE = 0.03) declined.

CONCLUSIONS AND IMPLICATIONS

Cognitive impairment is associated with a pattern of detrimental personality changes across the preclinical and clinical stages. Compared with the steeper rate of change during cognitive impairment, the changes were small and inconsistent before impairment, making them unlikely to be useful predictors of incident dementia. The study findings further indicate that individuals can update their personality ratings during the early stages of cognitive impairment, providing valuable information in clinical settings. The results also suggest an acceleration of personality change with the progression to dementia, which may lead to behavioral, emotional, and other psychological symptoms commonly observed in people with cognitive impairment and dementia.

Machine learning-based classification of Alzheimer's disease and its at-risk states using personality traits, anxiety, and depression

BACKGROUND

Alzheimer's disease (AD) is often preceded by stages of cognitive impairment, namely subjective cognitive decline (SCD) and mild cognitive impairment (MCI). While cerebrospinal fluid (CSF) biomarkers are established predictors of AD, other non-invasive candidate predictors include personality traits, anxiety, and depression, among others. These predictors offer non-invasive assessment and exhibit changes during AD development and preclinical stages.

METHODS

In a cross-sectional design, we comparatively evaluated the predictive value of personality traits (Big Five), geriatric anxiety and depression scores, resting-state functional magnetic resonance imaging activity of the default mode network, apoliprotein E (ApoE) genotype, and CSF biomarkers (tTau, pTau181, Aβ42/40 ratio) in a multi-class support vector machine classification. Participants included 189 healthy controls (HC), 338 individuals with SCD, 132 with amnestic MCI, and 74 with mild AD from the multicenter DZNE-Longitudinal Cognitive Impairment and Dementia Study (DELCODE).

RESULTS

Mean predictive accuracy across all participant groups was highest when utilizing a combination of personality, depression, and anxiety scores. HC were best predicted by a feature set comprised of depression and anxiety scores and participants with AD were best predicted by a feature set containing CSF biomarkers. Classification of participants with SCD or aMCI was near chance level for all assessed feature sets.

CONCLUSION

Our results demonstrate predictive value of personality trait and state scores for AD. Importantly, CSF biomarkers, personality, depression, anxiety, and ApoE genotype show complementary value for classification of AD and its at-risk stages.

Prediction of neuropathologic lesions from clinical data

INTRODUCTION

Post-mortem analysis provides definitive diagnoses of neurodegenerative diseases; however, only a few can be diagnosed during life.

METHODS

This study employed statistical tools and machine learning to predict 17 neuropathologic lesions from a cohort of 6518 individuals using 381 clinical features (Table S1). The multisite data allowed validation of the model's robustness by splitting train/test sets by clinical sites. A similar study was performed for predicting Alzheimer's disease (AD) neuropathologic change without specific comorbidities.

RESULTS

Prediction results show high performance for certain lesions that match or exceed that of research annotation. Neurodegenerative comorbidities in addition to AD neuropathologic change resulted in compounded, but disproportionate, effects across cognitive domains as the comorbidity number increased.

DISCUSSION

Certain clinical features could be strongly associated with multiple neurodegenerative diseases, others were lesion-specific, and some were divergent between lesions. Our approach could benefit clinical research, and genetic and biomarker research by enriching cohorts for desired lesions.

The associations between personality traits and quality of life, satisfaction with life, and well-being over time in people with dementia and their caregivers: findings from the IDEAL programme

BACKGROUND

Cross-sectional evidence indicates that certain personality traits may influence how well people with dementia and their caregivers are able to live alongside the condition. However, no studies to date have explored these associations longitudinally. The present study aimed to explore whether each of the Five-Factor personality traits were associated with change over two years in perceptions of 'living well' for people with dementia and their caregivers. 'Living well' was conceptualized as a composite of quality of life, satisfaction with life, and subjective well-being.

METHODS

Data were analyzed from 1487 people with dementia and 1234 caregivers who took part in the IDEAL cohort. Participants were categorized into low, medium, and high groups for each trait using stanine scores. Latent growth curve models investigated associations between these groups and 'living well' scores for each trait at baseline and at 12 and 24 months. Covariates included cognition in people with dementia and stress in caregivers. A Reliable Change Index was calculated against which to evaluate changes in 'living well' scores over time.

RESULTS

At baseline, neuroticism was negatively associated with 'living well' scores for people with dementia, while conscientiousness, extraversion, openness, and agreeableness were positively associated. For caregivers, neuroticism was negatively associated with 'living well' scores at baseline while conscientiousness and extraversion were positively associated. 'Living well' scores were mostly stable over time with no influence of personality traits on observed changes.

CONCLUSIONS

Findings suggest that personality traits, particularly neuroticism, have a meaningful impact on how people with dementia and caregivers rate their capability to 'live well' at baseline. Over time 'living well' scores for each personality trait group were largely stable. Studies utilizing longer follow-up periods and more appropriate measures of personality are needed to corroborate and extend the findings of the present study.

The relationship between optimism, MCI, and dementia among postmenopausal women

OBJECTIVES

The relationship between optimism and cognitive functioning is not fully understood. We examined the association of optimism with risk of mild cognitive impairment (MCI) and dementia in the Women's Health Initiative Memory Study (WHIMS).

METHODS

Optimism was measured by the Life Orientation Test-Revised (LOT-R) total score, and optimism and pessimism subscales. A panel of experts adjudicated cognitive endpoints based on annual cognitive assessments. We used cox proportional hazard regression models to examine the association of LOT-R total score and optimism and pessimism sub-scores with MCI/dementia. We also examined the relationship between vascular disease, LOT-R total score, optimism and pessimism, and cognition.

RESULTS

Mean age was 70.5 (SD = 3.9) years. The sample (N = 7249) was 87% white, and 29.8% of participants had < 12 years of education. Total LOT-R score (HR = 0.96, 95% CI: 0.94, 0.98, p < 0.001) was associated with lower risk of combined MCI or dementia. More pessimism (HR = 1.08, 95% CI: 1.05, 1.11, p < 0.0001) was associated with higher risk of MCI or dementia after adjustment for ethnicity, education, vascular disease, and depression. No significant relationships emerged from the optimism subscale.

CONCLUSION

These data suggest that less pessimism, but not more optimism, was associated with a lower risk of MCI and dementia.

Association between personality and cognitive performance in middle-aged and older adults with human immunodeficiency virus (HIV)

BACKGROUND

Nearly half of adults with human immunodeficiency virus (HIV) experience HIV-Associated Neurocognitive Disorder (HAND), characterized by cognitive impairments in two or more cognitive domains, which can interfere with everyday functioning. Many factors are thought to influence such cognitive impairments in adults with HIV; one factor seldom examined is personality.

OBJECTIVE

This study investigated the association between five major dimensions of personality (openness, conscientiousness, extraversion, agreeableness, and neuroticism) and cognitive function in older adults with HIV.

METHODS

In this cross-sectional study, a secondary data analysis was conducted on 261 HIV + participants. Participants completed a norm-based cognitive battery covering seven cognitive domains, which yielded the following indices: global cognitive impairment, and global and domain-specific T-scores. The Big Five Inventory was used to assess personality traits.

RESULTS

Higher openness, conscientiousness, and agreeableness were associated with better performance on individual cognitive domains while agreeableness and openness were also positively associated with global cognitive T-scores (p < .01). Only openness significantly predicted global cognition when adjusting for covariates (p < .01).

DISCUSSION

Openness was associated with better global cognitive function in persons with HIV. This study provides a basis for further investigation of potential mechanisms for the association between personality and cognition in people with HIV in order to ultimately inform intervention strategies.

Psychosocial Basis of Human Sufferings and Poverty in Patients with Neurological and Psychiatric Disorders

Neurological disorders and psychiatric ailments often lead to cognitive disabilities and low attainment of education, pivoting misconceptions, myths, and misbeliefs. Poverty and low educational attainment are intriguingly associated with poor awareness and perception of these diseases that add to the suffering. Poverty goes parallel with a low level of education and is intricately associated with neuropsychiatric ailments, which have the potential to spread transgenerationally. Robust education policies, proper government rules and regulations against the spread of disease-related myths and misconceptions, uplifting medical education in its true sense, voices against consanguinity, and programs to raise scientific perception about diseases can help to throw light at the end of this dark tunnel. In this article, the authors intend to 1) decipher the potential psychosocial basis of human suffering and poverty in patients with neurological and psychiatric disorders, and 2) discuss the apropos way-outs that would potentially mitigate suffering, and alleviate the economic burden and cognitive disabilities of families with neuropsychiatric diseases.

Personality traits and disorders in Alzheimer's disease

BACKGROUND

The relationships between axis II personality disorders and the normative personality traits were explored in the context of current and pre-morbid personality assessment in Alzheimer's disease (AD).

METHODS

The study was conducted with four groups who were administered the NEO-FFI and the PDQ-4+, in the form of individual interview sessions. Current personality measure: consisting of 44 female participants (AD group) and, the control group, consisting of 80 female participants from the population at large. Pre-morbid personality measure: AD group informants (n = 40); control group informants (n = 42).

RESULTS

The results are in line with the literature review and provide new research data. By factorial discriminant analysis, the current and pre-morbid personality variables that differentiate AD from control groups are identified. The personality traits variables are the best discriminators such as low agreeableness, low openness to experience, and high neuroticism, suggesting that the maladaptive personality functioning can be described extending the range of psychopathology to a dimensional approach.

CONCLUSIONS

The study of personality variables seems to suggest, in their inclusion, the possibility to increase sensitivity toward an assessment in AD.

Behavioral and psychological symptoms in neurodegenerative dementias: harbinger, follower, or constant collateral?

Neurodegenerative dementias such as the behavioral variant of frontotemporal dementia, Alzheimer’s disease, and Parkinson’s disease dementia are linked to various behavioral and psychological abnormalities. Whether these abnormalities precede, coincide or follow the onset of cognitive symptoms is still controversial in existing literature, with trajectories available so far dependent on types of dementia. The authors aim to review the different kinds of premorbid behavioral symptoms/personality traits associated with an increased risk of developing specific types of neurodegenerative dementia. Neuroticism has been associated with an increased risk of Alzheimer’s disease and late-onset behavioral abnormalities with the behavioral variant of frontotemporal dementia. The presence of obsessive–compulsive spectrum disorders in Parkinson’s disease dementia is also not rare. Analyzing this evidence, we propose “behavioral biomarkers” as neuroticism in Alzheimer’s disease, late-onset behavioral abnormalities in behavioral variant of frontotemporal dementia, and obsessive–compulsive traits in Parkinson’s disease dementia. These noninvasive behavioral biomarkers will be of immense help, particularly in developing countries, and will prevent the need for costlier investigations and aid in therapeutic strategies.

Relationship between Nutrition, Lifestyle, and Neurodegenerative Disease: Lessons from ADH1B, CYP1A2 and MTHFR

In the present review, the main features involved in the susceptibility and progression of neurodegenerative disorders (NDDs) have been discussed, with the purpose of highlighting their potential application for promoting the management and treatment of patients with NDDs. In particular, the impact of genetic and epigenetic factors, nutrients, and lifestyle will be presented, with particular emphasis on Alzheimer’s disease (AD) and Parkinson’s disease (PD). Metabolism, dietary habits, physical exercise and microbiota are part of a complex network that is crucial for brain function and preservation. This complex equilibrium can be disrupted by genetic, epigenetic, and environmental factors causing perturbations in central nervous system homeostasis, contributing thereby to neuroinflammation and neurodegeneration. Diet and physical activity can directly act on epigenetic modifications, which, in turn, alter the expression of specific genes involved in NDDs onset and progression. On this subject, the introduction of nutrigenomics shed light on the main molecular players involved in the modulation of health and disease status. In particular, the review presents data concerning the impact of ADH1B, CYP1A2, and MTHFR on the susceptibility and progression of NDDs (especially AD and PD) and how they may be exploited for developing precision medicine strategies for the disease treatment and management.

Facets of Personality and Risk of Cognitive Impairment: Longitudinal Findings in a Rural Community from Sardinia

Background: Few studies have examined the associations between personality facets and dementia risk and rarely included individuals from rural settings or with low education. Objective: To examine the association between personality and the risk of cognitive impairment. Methods: Participants (N = 1,668; age 50 to 94 at baseline; 56.4% women; 86.5% less than high school diploma) were from a rural region of Sardinia (Italy) who completed the Revised NEO Personality Inventory (NEO-PI-R) during the first wave (2001–2004) and the Mini-Mental State Examination (MMSE) at waves two to five (2005–2021). Cox regression was used to test personality and covariates as predictors of cognitive impairment based on MMSE education-adjusted cutoffs. Results: During the up to 18-year follow-up (M = 10.38; SD = 4.76), 187 individuals (11.2%) scored as cognitively impaired. Participants with higher neuroticism (particularly the depression facet [HR = 1.22, 95% CI = 1.06–1.40]), and lower agreeableness (particularly the modesty facet [HR = 0.83, 95% CI = 0.71–0.97]) and lower conscientiousness (particularly the dutifulness facet [HR = 0.78, 95% CI = 0.67–0.92]) were at higher risk of cognitive impairment. Lower warmth ([HR = 0.75, 95% CI = 0.65–0.87], facet of extraversion) and ideas ([HR = 0.76, 95% CI = 0.65–0.89], facet of openness) were also associated with increased risk of impairment. These associations were virtually unchanged in models that accounted for other risk factors, including smoking, depression, obesity, hypertension, diabetes, and apolipoprotein E (APOE) ɛ4 carrier status. Across the five domains, sex and the APOE variant did not moderate the associations. Conclusion: In a sample with demographic characteristics underrepresented in dementia research, this study identifies personality domains and facets most relevant to the risk of cognitive impairment.

Associations of Polygenic Risk Score for Late-Onset Alzheimer's Disease With Biomarkers

Late-onset Alzheimer's disease (LOAD) is a common irreversible neurodegenerative disease with heterogeneous genetic characteristics. Identifying the biological biomarkers with the potential to predict the conversion from normal controls to LOAD is clinically important for early interventions of LOAD and clinical treatment. The polygenic risk score for LOAD (AD-PRS) has been reported the potential possibility for reliably identifying individuals with risk of developing LOAD recently. To investigate the external phenotype changes resulting from LOAD and the underlying etiology, we summarize the comprehensive associations of AD-PRS with multiple biomarkers, including neuroimaging, cerebrospinal fluid and plasma biomarkers, cardiovascular risk factors, cognitive behavior, and mental health. This systematic review helps improve the understanding of the biomarkers with potential predictive value for LOAD and further optimizing the prediction and accurate treatment of LOAD.

Changes in personality traits in patients with Alzheimer's Disease

Changes in personality traits in patients with Alzheimer's disease (AD) are extremely common throughout the course of the pathology, and these behavioral changes present themselves as challenges in clinical management and as a significant cause of caregivers’ burden.

Decision-making tips for patients with dementia

BACKGROUND

When patients with advanced dementia lose capacity to make medical decisions for themselves, a 'best interests' determination is usually made on their behalf by the responsible clinician. Where possible, this should be made in consultation with members of the multiprofessional team and the family, consistent with ethical and legal norms. This paper is about multidisciplinary approaches to education and practice in dementia care, using a framework.

APPROACH

At a UK multiprofessional workshop in 2020, delegates discussed ethical and legal issues that arise when making decisions for patients with advanced dementia. After an initial presentation, providing context and background, delegates broke into small groups. They were tasked with responding to questions arising from anonymised cases based on real-life scenarios. During plenary discussion afterwards, feedback was shared, and points of best practice were discussed. The authors took notes, and following positive evaluations after the event, they did further work on the framework with the intention of making it available for other health care professionals and clinical educators.

EVALUATION

Based on contemporaneous notes summarising the feedback, plus further reflections, the framework was developed into a 12-point plan to assist health care teams and educators address difficulties in making 'best interests' determinations.

IMPLICATIONS

Promoting understanding of ethics and law pertaining to 'best interests' should benefit patients and families, with the potential to reduce the need for cases to be decided in court. To help promote good clinical practice, educators may want to consider running case-based workshops at their institution, using the framework as a scaffold for learners.

Personality pathology predicts increased informant-reported, but not performance-based, cognitive decline: Findings from two samples

Research on the relationship between normal-range personality and cognitive aging has demonstrated consistent, modest effects. The current investigation increases our understanding of unhealthy cognitive aging by testing whether personality disorders (PDs), specifically borderline, avoidant, and obsessive-compulsive PDs, show prospective associations with the onset of cognitive problems. Interpersonal stressful life events and social support were expected to mediate these relationships. The current investigation used data from 2 longitudinal studies of older adulthood: the Alzheimer's disease Research Center cohort (ADRC, N = 434, Mage = 69.95, 56% women) and the St. Louis Personality and Aging Network study (SPAN, N = 1,058, Mage = 65.92, 54% women). The ADRC study administered a battery of neuropsychological tests to assess cognitive ability/memory. Borderline PD was measured with a composite from the NEO Five-Factor Inventory. The SPAN study administered self-, informant, and interview measures of the three PDs; a free-recall task; and an informant report measure of cognitive problems. Borderline PD features exhibited cross-sectional correlations with memory (ADRC: r = -.11; SPAN: all rs = -.08), general cognitive ability (ADRC: r = -.11), and informant-reported cognitive problems (rs ranged from .15 to .39). Most importantly, borderline PD features predicted an increase in informant-reported cognitive problems in SPAN participants (standardized bs = .13 and .15) over a 2-year period, but they did not predict a deterioration in the performance-based cognitive measures in either study. Avoidant and obsessive-compulsive PDs exhibited little association with cognitive aging. Neither interpersonal variable mediated any of these effects. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Psychosocial and Trauma-Related Stress and Risk of Dementia: A Meta-Analytic Systematic Review of Longitudinal Studies

Stress has deleterious effects on brain health and yet, the prognostic value of psychosocial stress regarding the most common types of dementias, including Alzheimer disease, is still unclear. The primary aim of this systematic review was to explore the association between psychosocial stress and late onset dementia. We classified 24articles from Medline, PsycINFO, CINAHL, and Web of Science, as pertaining toxic categories of psychosocial and trauma-related stress (low socio-economic status [SES] related inequalities, marital status, posttraumatic stress disorder, work stress, "vital exhaustion" [VE], and, combined stressors). Using the Quality of Prognosis Studies in Systematic Reviews tool, we judged the quality of evidence to be low. This systematic review provided some non-robust, yet suggestive evidence that the above psychosocial types of stress are associated with increased risk of dementia in later life. Future robust, longitudinal studies with repeated validated measures of psychosocial stress and dementiaare required to strengthen or refute these findings.

Personality traits are consistently associated with blood mitochondrial DNA copy number estimated from genome sequences in two genetic cohort studies

Background

Mitochondrial DNA copy number (mtDNAcn) in tissues and blood can be altered in conditions like diabetes and major depression and may play a role in aging and longevity. However, little is known about the association between mtDNAcn and personality traits linked to emotional states, metabolic health, and longevity. This study tests the hypothesis that blood mtDNAcn is related to personality traits and mediates the association between personality and mortality.

Methods

We assessed the big five personality domains and facets using the Revised NEO Personality Inventory (NEO-PI-R), assessed depressive symptoms with the Center for Epidemiologic Studies Depression Scale (CES-D), estimated mtDNAcn levels from whole-genome sequencing, and tracked mortality in participants from the Baltimore Longitudinal Study of Aging. Results were replicated in the SardiNIA Project.

Results

We found that mtDNAcn was negatively associated with the Neuroticism domain and its facets and positively associated with facets from the other four domains. The direction and size of the effects were replicated in the SardiNIA cohort and were robust to adjustment for potential confounders in both samples. Consistent with the Neuroticism finding, higher depressive symptoms were associated with lower mtDNAcn. Finally, mtDNAcn mediated the association between personality and mortality risk.

Conclusions

To our knowledge, this is the first study to show a replicable association between mtDNAcn and personality. Furthermore, the results support our hypothesis that mtDNAcn is a biomarker of the biological process that explains part of the association between personality and mortality.

Funding

Support for this work was provided by the Intramural Research Program of the National Institute on Aging (Z01-AG000693, Z01-AG000970, and Z01-AG000949) and the National Institute of Neurological Disorders and Stroke of the National Institutes of Health. AT was also supported by the National Institute on Aging of the National Institutes of Health Grant R01AG068093.

Subjective Cognitive Decline: Is a Resilient Personality Protective Against Progression to Objective Cognitive Impairment? Findings from Two Community-Based Cohort Studies

BACKGROUND

Subjective cognitive decline (SCD) is related to personality functioning and risk of subsequent objective cognitive impairment.

OBJECTIVE

The aim of this study was to examine whether lower neuroticism and higher conscientiousness-resilient personality traits-protect against conversion from SCD to objective cognitive impairment in two longitudinal community-based cohorts.

METHODS

Data from the Health and Retirement Study (N = 1,741, Mean age = 68.64 years, Follow-up mean = 7.34 years) and the National Health and Aging Trends Survey (N = 258, Mean age = 79.34 years, Follow-up mean = 4.31 years) were analyzed using Cox regression analysis, controlling for sociodemographic covariates, symptoms of anxiety and depression, and apolipoprotein ɛ4.

RESULTS

The pooled results showed that lower neuroticism and higher conscientiousness were associated with decreased risk of conversion from SCD to objective cognitive impairment.

CONCLUSION

Among individuals with SCD, those with a resilient personality may have more cognitive and psychological reserve to maintain cognitive functioning and delay conversion to objective cognitive impairment. The findings further contribute to a better understanding of personality along the cognitive continuum: The observed effect sizes were smaller than those reported in cognitively normal individuals but larger than in individuals with mild cognitive impairment. Personality could provide useful information to identify individuals with SCD who may develop objective cognitive impairment-namely those who hold a vulnerable personality (higher neuroticism, lower conscientiousness).

Determinants of Cognitive Trajectories in Normal Aging: A Longitudinal PET-MRI Study in a Community-based Cohort

BACKGROUND

The determinants of the progressive decrement of cognition in normal aging are still a matter of debate. Alzheimer disease (AD)-signature markers and vascular lesions, but also psychological variables such as personality factors, are thought to have an impact on the longitudinal trajectories of neuropsychological performances in healthy elderly individuals.

OBJECTIVE

The current research aimed to identify the main determinants associated with cognitive trajectories in normal aging.

METHODS

We performed a 4.5-year longitudinal study in 90 older community-dwellers coupling two neuropsychological assessments, medial temporal atrophy (MTA), number of cerebral microbleeds (CMB), and white matter hyperintensities (WMH) at inclusion, visual rating of amyloid and FDG PET at follow-up, and APOE genotyping. Personality factors were assessed at baseline using the NEO-PIR. Univariate and backward stepwise regression models were built to explore the association between the continuous cognitive score (CCS) and both imaging and personality variables.

RESULTS

The number of strictly lobar CMB at baseline (4 or more) was related to a significant increase in the risk of cognitive decrement. In multivariable models, amyloid positivity was associated with a 1.73 unit decrease of the CCS at follow-up. MTA, WMH and abnormal FDG PET were not related to the cognitive outcome. Among personality factors, only higher agreeableness was related to better preservation of neuropsychological performances.

CONCLUSION

CMB and amyloid positivity are the only imaging determinants of cognitive trajectories in this highly selected series of healthy controls. Among personality factors, higher agreeableness confers a modest but significant protection against the decline of cognitive performances.

The cognitive dysfunction related to Alzheimer disease or cerebral small vessel disease: What's the differences

ABSTRACT

Alzheimer disease (AD) and sporadic cerebral small vessel disease (CSVD) are common cognitive disorders. Both AD and CSVD have mental symptoms including chronic progressive cognitive impairment, dysfunction, and behavioral abnormalities. However, the differences on the cognitive dysfunction of AD and CSVD remain unclear. It is necessary to elucidate the cognitive dysfunction differences of AD and CSVD, and to identify the potential risk factors.AD or sporadic CSVD patients treated in our hospital from December 1, 2018 to May 31, 2019 were included. And we selected healthy participants as controls. The mini-mental state examination and Montreal Cognitive Assessment Scale were used for neuropsychological assessment, and related medical information were collected and compared.A total of 190 patients were included. The total mini-mental state examination scores in AD, CSVD group were significantly less than that of control group, there were significant differences in the domains of directional ability, attention and computing ability, delayed recall, and visual perception (all P < .05); the total Montreal Cognitive Assessment Scale scores in AD, CSVD group were significantly less than that of control group. There were significant differences in the domains of visual space and execution, immediate remember, attention and computing ability, language, delayed recall, and directional ability (all P < .05); diabetes was a risk factor both for AD (hazard ratio = 1.63, 95% confidence interval: 1.35-1.97) and CSVD (hazard ratio = 1.15, 95% confidence interval: 1.08-1.27).The cognitive dysfunctions of AD are difference to that of CSVD patients, and diabetes is the risk factor both for AD and CSVD, future studies are needed to further identify the prevention and treatment of AD and CSVD.

Neuroticism Is Associated with Tau Pathology in Cognitively Unimpaired Individuals with Autosomal Dominant Alzheimer's Disease

BACKGROUND

Greater neuroticism has been associated with higher risk for Alzheimer's disease (AD) dementia. However, the directionality of this association is unclear. We examined whether personality traits differ between cognitively-unimpaired carriers of autosomal-dominant AD (ADAD) and non-carriers, and are associated with in vivo AD pathology.

OBJECTIVE

To determine whether personality traits differ between cognitively unimpaired ADAD mutation carriers and non-carriers, and whether the traits are related to age and AD biomarkers.

METHODS

A total of 33 cognitively-unimpaired Presenilin-1 E280A mutation carriers and 41 non-carriers (ages 27-46) completed neuropsychological testing and the NEO Five-Factor Personality Inventory. A subsample (n = 46; 20 carriers) also underwent tau and amyloid PET imaging.

RESULTS

Carriers reported higher neuroticism relative to non-carriers, although this difference was not significant after controlling for sex. Neuroticism was positively correlated with entorhinal tau levels only in carriers, but not with amyloid levels.

CONCLUSION

The finding of higher neuroticism in carriers and the association of this trait with tau pathology in preclinical stages of AD highlights the importance of including personality measures in the evaluation of individuals at increased risk for cognitive impairment and dementia. Further research is needed to characterize the mechanisms of these relationships.

Neuroticism and Risk of Parkinson's Disease: A Meta-Analysis

BACKGROUND

Neuroticism is linked to mood disorders and Alzheimer's disease, but fewer studies have tested the prospective association with Parkinson's disease (PD).

OBJECTIVES

To examine the association between neuroticism and risk of PD in a large cohort and a meta-analysis of prospective cohort studies.

METHODS

Participants from the UK Biobank (N = 490,755) completed a neuroticism scale in 2006-2010. Incident PD was ascertained using electronic health records or death records up to 2018. The systematic search and meta-analysis followed the MOOSE guidelines.

RESULTS

During 11.91 years of follow-up (mean = 8.88 years; 4,360,105 person-years) 1142 incident PD cases were identified. Neuroticism was associated with higher risk of incident PD, both as continuous (HR = 1.28; 95% CI: 1.21-1.36) and categorical variable (top vs. bottom quartiles: HR = 1.88; 95% CI: 1.60-2.22). The association remained significant after accounting for age, sex, smoking, physical activity, anxiety, and depressed mood, and after excluding cases that occurred within the first 5 years of follow-up. The associations were similar for women and men and across levels of socioeconomic status. Random-effect meta-analysis of four prospective studies (N = 548,284) found neuroticism associated with increased risk of incident PD (HR = 1.82; 95% CI: 1.59-2.08; P = 7.31-19 ). There was no evidence of heterogeneity across studies with follow-ups ranging from one to four decades.

CONCLUSION

The results from the large UK Biobank and meta-analysis of prospective studies indicate that neuroticism is consistently associated with a higher risk of incident PD. © 2021 International Parkinson and Movement Disorder Society.

Is neuroticism differentially associated with risk of Alzheimer's disease, vascular dementia, and frontotemporal dementia?

This study examines whether neuroticism is differentially associated with risk of incident Alzheimer's disease (AD), vascular dementia (VD), and frontotemporal dementia (FTD) using a prospective study design. Participants from the UK Biobank (N = 401,422) completed a self-report neuroticism scale in 2006-2010 and incident all-cause dementia, AD, VD, and FTD were ascertained using electronic health records or death records up to 2018. During an average follow-up of 8.8 years (3,566,123 person-years), there were 1798 incident of all-cause dementia, 675 AD, 376 VD, and 81 FTD. Accounting for age and sex, compared to individuals in the low quartile, individuals in the top quartile of neuroticism had higher risk of all-cause dementia (HR = 1.70; 95% CI: 1.49-1.93), AD (HR = 1.42; 1.15-1.75), VD (HR = 1.73; 1.30-2.29), but not FTD (HR = 0.89; 0.49-1.63). The associations with AD and VD were attenuated but remained significant after further accounting for education, household income, deprivation index, diabetes, hypertension, stroke, heart attack, ever smoker, physical activity, obesity, hemoglobin A1c, C-reactive protein, and low-density lipoprotein. The associations were not moderated by socioeconomic status. The findings were consistent in analyses that excluded cases that occurred within the first 5 years of follow-up. In conclusion, neuroticism is a robust predictor of incident AD and VD, but not FTD. This pattern suggests that the affective symptoms that distinguish dementia types may partly reflect premorbid differences in trait neuroticism.

Predicting Cognitive Impairment and Dementia: A Machine Learning Approach

BACKGROUND

Efforts to identify important risk factors for cognitive impairment and dementia have to date mostly relied on meta-analytic strategies. A comprehensive empirical evaluation of these risk factors within a single study is currently lacking.

OBJECTIVE

We used a combined methodology of machine learning and semi-parametric survival analysis to estimate the relative importance of 52 predictors in forecasting cognitive impairment and dementia in a large, population-representative sample of older adults.

METHODS

Participants from the Health and Retirement Study (N = 9,979; aged 50-98 years) were followed for up to 10 years (M = 6.85 for cognitive impairment; M = 7.67 for dementia). Using a split-sample methodology, we first estimated the relative importance of predictors using machine learning (random forest survival analysis), and we then used semi-parametric survival analysis (Cox proportional hazards) to estimate effect sizes for the most important variables.

RESULTS

African Americans and individuals who scored high on emotional distress were at relatively highest risk for developing cognitive impairment and dementia. Sociodemographic (lower education, Hispanic ethnicity) and health variables (worse subjective health, increasing BMI) were comparatively strong predictors for cognitive impairment. Cardiovascular factors (e.g., smoking, physical inactivity) and polygenic scores (with and without APOEɛ4) appeared less important than expected. Post-hoc sensitivity analyses underscored the robustness of these results.

CONCLUSIONS

Higher-order factors (e.g., emotional distress, subjective health), which reflect complex interactions between various aspects of an individual, were more important than narrowly defined factors (e.g., clinical and behavioral indicators) when evaluated concurrently to predict cognitive impairment and dementia.

Evaluation relationships between subjective wellbeing, personality traits, and Alzheimer's disease: A two-sample Mendelian randomization study

OBJECTIVE

Observational studies have suggested that subjective wellbeing and personality traits link to risk of Alzheimer's disease (AD), but it is unclear if these associations are causal.

METHODS

We performed two-sample Mendelian randomization to assess potential causality. Genetic associations were obtained from the largest genome-wide association studies in Social Science Genetic Association Consortium (N = 298,420), Genetics of Personality Consortium (N = 81,036), and four independent consortia of AD (N = 455,258). We run the inverse variance weighted (IVW) approach as one primary analysis. A Bonferroni-corrected threshold of p < 8.33 × 10-3 was considered significant, and p values between 8.33 × 10-3 and 0.05 were considered to be suggestive of an association.

RESULTS

The suggestive association with decreased risk of AD was noted for a genetically predicted 1-SD increase in subjective wellbeing (odds ratio = 0.963, 95% confidence interval = 0.930-0.997; p = 0.032). Genetically predicted greater neuroticism was significantly associated with lower subjective wellbeing (β = -0.077; p = 0.004). No putative personality traits were significantly associated with AD risk after correction for multiple tests, including agreeableness (β = -0.0010; p = 0.477), conscientiousness (β = 0.0018; p = 0.270), openness (β = 0.0004; p = 0.738), neuroticism (β = -0.0098; p = 0.262), or extraversion (β = 0.0120; p = 0.262).

CONCLUSIONS

Subjective wellbeing may independently reduce the risk of AD. Residual confounding is likely to be responsible for the previous observational relationships between personality traits and AD.

Personality and behavioral changes after brain tumor resection: a lesion mapping study

BACKGROUND

Cognitive functioning is generally well preserved in patients with diffuse low-grade glioma (DLGG), even in the case of extended tumor and resection. To date, the question of personality changes in these patients has received little attention. Our aim was to investigate to what extent certain aspects of personality and behaviors could be affected by DLGG resection.

METHODS

We used self-reported personality questionnaires (NOEPI-R and TCI-R) and hetero-evaluation of executive behavioral changes in a large sample of 98 patients operated on for DLGG. To compare the patients' scores from the personality questionnaires, we recruited 47 healthy controls participants. To identify the putative neural networks associated with behavioral changes, a combination of voxel-wise and tract-wise lesion-symptom mapping was performed.

RESULTS

First, results revealed no difference between patients and controls for each subdimension of the NOEPI-R. Regarding the TCI-R, the character dimensions and three out of four temperament dimensions did not differ. Second, behavioral changes (Irritability, Hypoactivity, Anticipative disorders, and disinterest) were reported between 40 and 50% of cases. Third, some personality dimensions (as neuroticism) were strongly predictive of postoperative behavioral disorders (as hypoactivity). Lastly, specific behavioral changes were associated with selective damage to cortical (left inferior frontal gyrus, supplementary motor area, and right fusiform gyrus) and white matter (left inferior fronto-occipital and uncinate fasciculi, right cingulum) structures.

CONCLUSION

This study demonstrates that extensive lesions caused by DLGGs and their surgical resection have no or minor impact on patients' personality. However, specific personality dimensions are strongly predictive of behavioral disorders suggesting that the observed surgically related behavioral changes are modulated by the personality profile. Finally, the lesion mapping analyses indicate that damage to differential cortical or white matter structures leads to distinct patterns of behavioral abnormalities.

Amyloid and Tau Pathology Associations With Personality Traits, Neuropsychiatric Symptoms, and Cognitive Lifestyle in the Preclinical Phases of Sporadic and Autosomal Dominant Alzheimer's Disease

BACKGROUND

Major prevention trials for Alzheimer's disease (AD) are now focusing on multidomain lifestyle interventions. However, the exact combination of behavioral factors related to AD pathology remains unclear. In 2 cohorts of cognitively unimpaired individuals at risk of AD, we examined which combinations of personality traits, neuropsychiatric symptoms, and cognitive lifestyle (years of education or lifetime cognitive activity) related to the pathological hallmarks of AD, amyloid-β, and tau deposits.

METHODS

A total of 115 older adults with a parental or multiple-sibling family history of sporadic AD (PREVENT-AD [PRe-symptomatic EValuation of Experimental or Novel Treatments for AD] cohort) underwent amyloid and tau positron emission tomography and answered several questionnaires related to behavioral attributes. Separately, we studied 117 mutation carriers from the DIAN (Dominant Inherited Alzheimer Network) study group cohort with amyloid positron emission tomography and behavioral data. Using partial least squares analysis, we identified latent variables relating amyloid or tau pathology with combinations of personality traits, neuropsychiatric symptoms, and cognitive lifestyle.

RESULTS

In PREVENT-AD, lower neuroticism, neuropsychiatric burden, and higher education were associated with less amyloid deposition (p = .014). Lower neuroticism and neuropsychiatric features, along with higher measures of openness and extraversion, were related to less tau deposition (p = .006). In DIAN, lower neuropsychiatric burden and higher education were also associated with less amyloid (p = .005). The combination of these factors accounted for up to 14% of AD pathology.

CONCLUSIONS

In the preclinical phase of both sporadic and autosomal dominant AD, multiple behavioral features were associated with AD pathology. These results may suggest potential pathways by which multidomain interventions might help delay AD onset or progression.

Heterogeneous distribution of tau pathology in the behavioural variant of Alzheimer's disease

OBJECTIVE

The clinical phenotype of the rare behavioural variant of Alzheimer's disease (bvAD) is insufficiently understood. Given the strong clinico-anatomical correlations of tau pathology in AD, we investigated the distribution of tau deposits in bvAD, in-vivo and ex-vivo, using positron emission tomography (PET) and postmortem examination.

METHODS

For the tau PET study, seven amyloid-β positive bvAD patients underwent [18F]flortaucipir or [18F]RO948 PET. We converted tau PET uptake values into standardised (W-)scores, adjusting for age, sex and mini mental state examination in a 'typical' memory-predominant AD (n=205) group. W-scores were computed within entorhinal, temporoparietal, medial and lateral prefrontal, insular and whole-brain regions-of-interest, frontal-to-entorhinal and frontal-to-parietal ratios and within intrinsic functional connectivity network templates. For the postmortem study, the percentage of AT8 (tau)-positive area in hippocampus CA1, temporal, parietal, frontal and insular cortices were compared between autopsy-confirmed patients with bvAD (n=8) and typical AD (tAD;n=7).

RESULTS

Individual regional W-scores ≥1.96 (corresponding to p<0.05) were observed in three cases, that is, case #5: medial prefrontal cortex (W=2.13) and anterior default mode network (W=3.79), case #2: lateral prefrontal cortex (W=2.79) and salience network (W=2.77), and case #7: frontal-to-entorhinal ratio (W=2.04). The remaining four cases fell within the normal distributions of the tAD group. Postmortem AT8 staining indicated no group-level regional differences in phosphorylated tau levels between bvAD and tAD (all p>0.05).

CONCLUSIONS

Both in-vivo and ex-vivo, patients with bvAD showed heterogeneous distributions of tau pathology. Since key regions involved in behavioural regulation were not consistently disproportionally affected by tau pathology, other factors are more likely driving the clinical phenotype in bvAD.

Trait anxiety, a personality risk factor associated with Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disease in elderly population and the leading cause of dementia worldwide. While senile plaques and neurofibrillary tangles have been proposed as the principal histopathologic hallmarks of AD, the exact etiology of this disease is still far from being clearly understood. AD has been recognized as pathological consequences of complex interactions among genetic, aging, medical, life style and psychosocial factors. Recently, the roles of neuroticism personality traits in AD incidence and progression have come into focus. More specifically, increasing evidence has further shown that the trait anxiety, one major component of neuroticism predicting the individual vulnerability in response to stress, is a risk factor for AD and may correlated with various AD pathologies. In this review, we summarized recent literature on the association of trait anxiety with AD. We also discussed the possible neuroendocrinological and neurochemical mechanisms of this association, which may provide clinical implications for AD diagnosis and therapy.

Personality pathways to mortality: Interleukin-6 links conscientiousness to mortality risk

Personality is associated consistently with mortality hazards, but the physiological pathways are not yet clear. Immune system dysregulation may be one such pathway due to its role in age-related morbidity and mortality. In this preregistered study, we tested whether interleukin-6 (IL-6) and C-reactive protein (CRP) mediated the associations between personality traits and mortality hazards. The sample included 957 participants (M ± SD = 58.65 ± 11.51 years; range = 35-86 years) from the Midlife in the United States Survey that had 14 years of follow-up. Higher conscientiousness was associated with lower mortality hazards, with each one standard deviation higher conscientiousness associated with a 35% lower mortality risk. IL-6, but not CRP, partially mediated this association, with IL-6 accounting for 18% of this association in the fully adjusted model. While there was initial evidence that the biomarkers mediated both neuroticism and agreeableness and mortality risk, the indirect effects were not significant when controlling for the sociodemographic variables. Taken together, higher conscientiousness may lead to a longer life partially as a result of lower IL-6. This work highlights the importance of biological pathways that link personality to future mortality risk.

Personality, Retirement, and Cognitive Impairment: Moderating and Mediating Associations

Objectives: Five-factor model (FFM) personality traits, including higher conscientiousness and lower neuroticism, are associated with lower risk of dementia and cognitive impairment. In this research, we test whether retirement status moderates and/or mediates the relation between personality and cognitive impairment. Method: We used data from the Health and Retirement Study (N = 9899), a longitudinal study of Americans over the age of 50 years, to examine moderating and mediating associations between personality traits and retirement status on risk of dementia and cognitive impairment not dementia (CIND) over an 8-10 year follow-up. Results: Personality and retirement each had strong, independent associations with risk of dementia and CIND. There were not, however, strong or consistent, moderating or mediating associations between personality and retirement predicting impairment risk. Discussion: Overall, these results indicate that personality and retirement are independent risk factors for incident cognitive impairment. Mechanisms other than retirement are likely to explain this association.

Characterizing dementia caregiver style in managing care challenges: Cognitive and behavioral components

BACKGROUND

Caring for a person living with dementia can take a physical and emotional toll, but understudied is the process by which family caregivers actually provide care. Caregiver management styles may vary and affect care decision-making, experiences, receptivity to and participation in interventions, and outcomes for the caregiver and person living with dementia.

METHODS

Participants included 100 primary family caregivers for persons with dementia who were on average 64 years old and had been providing care for 55 months, 74% women, and 18% nonwhite. Participants were interviewed in Michigan and Ohio regarding their cognitive and behavioral management of a recent care challenge and values guiding their decision-making. The rigorous and accelerated data reduction technique was used to analyze qualitative data leading to the identification of caregiving styles. Styles were compared across sample characteristics using chi-square and ANOVA tests.

FINDINGS

Five distinct styles emerged: "Externalizers" (superficial understanding, self-focused, and frequent expressions of anger or frustration), "Individualists" (provide care by going alone, emotionally removed, and lack management strategies), "Learners" (recognize need to change their approach but are stuck and emotionally turbulent), "Nurturers" (positive affect and empathy toward care and reflect natural mastery), and "Adapters" (arsenal of acquired management strategies and adapt to challenges). Style groups differed significantly in terms of age and use of formal care supports.

DISCUSSION

We identified five distinct styles by which caregivers addressed care challenges using a robust qualitative methodology. Styles may be important to identify in order to better tailor interventions to needs and abilities.

Interactions between Personality, Depression, Anxiety and Cognition to Understand Early Stage of Alzheimer's Disease

The multifaceted nature of Alzheimer's disease (AD) and Mild cognitive impairment (MCI) can lead to wide inter-individual differences in disease manifestation in terms of brain pathology and cognition. The lack of understanding of phenotypic diversity in AD arises from a difficulty in understanding the integration of different levels of network organization (i.e. genes, neurons, synapses, anatomical regions, functions) and in inclusion of other information such as neuropsychiatric characteristics, personal history, information regarding general health or subjective cognitive complaints in a coherent model. Non-cognitive factors, such as personality traits and behavioral and psychiatric symptoms, can be informative markers of early disease stage. It is known that personality can affect cognition and behavioral symptoms. The aim of the paper is to review the different types of interactions existing between personality, depression/anxiety, and cognition and cognitive disorders at behavioral and brain/genetic levels.

Associations Between Personality Traits and Cognitive Resilience in Older Adults

OBJECTIVES

The goal of this paper was to examine associations between personality traits and resilience to neuropathologic burden.

METHOD

Using data from the Religious Orders Study and the Rush Memory and Aging Project, we identified a total of 1,375 participants with personality, cognitive, and post-mortem neuropathology data. We regressed cognition onto pathology and extracted the residuals as an indicator of cognitive resilience. We then modeled the effect of Big Five personality traits on cognitive resilience, adjusting for demographics, APOE status, medical comorbidities, and cognitive activity. The analytic plan was preregistered prior to data access or analysis, and all scripts and outputs are available online.

RESULTS

Higher neuroticism was associated with greater vulnerability to pathology. Results from exploratory analyses suggest that higher conscientiousness was associated with less cognitive decline relative to the amount of pathology, or greater resilience. Education and cognitive activity did not moderate these associations.

DISCUSSION

Personality may have a pathoplastic effect on neuropathology, as low neuroticism and high conscientiousness are associated with better function despite neuropathologic burden.

Neuropsychiatric Symptoms in Mild Cognitive Impairment and Dementia Due to AD: Relation With Disease Stage and Cognitive Deficits

Background: The interaction between neuropsychiatric symptoms, mild cognitive impairment (MCI), and dementia is complex and remains to be elucidated. An additive or multiplicative effect of neuropsychiatric symptoms such as apathy or depression on cognitive decline has been suggested. Unraveling these interactions may allow the development of better prevention and treatment strategies. In the absence of available treatments for neurodegeneration, a timely and adequate identification of neuropsychiatric symptom changes in cognitive decline is highly relevant and can help identify treatment targets. Methods: An existing memory clinic-based research database of 476 individuals with MCI and 978 individuals with dementia due to Alzheimer's disease (AD) was reanalyzed. Neuropsychiatric symptoms were assessed in a prospective fashion using a battery of neuropsychiatric assessment scales: Middelheim Frontality Score, Behavioral Pathology in Alzheimer's Disease Rating Scale (Behave-AD), Cohen-Mansfield Agitation Inventory, Cornell Scale for Depression in Dementia (CSDD), and Geriatric Depression Scale (30 items). We subtyped subjects suffering from dementia as mild, moderate, or severe according to their Mini-Mental State Examination (MMSE) score and compared neuropsychiatric scores across these groups. A group of 126 subjects suffering from AD with a significant cerebrovascular component was examined separately as well. We compared the prevalence, nature, and severity of neuropsychiatric symptoms between subgroups of patients with MCI and dementia due to AD in a cross-sectional analysis. Results: Affective and sleep-related symptoms are common in MCI and remain constant in prevalence and severity across dementia groups. Depressive symptoms as assessed by the CSDD further increase in severe dementia. Most other neuropsychiatric symptoms (such as agitation and activity disturbances) progress in parallel with severity of cognitive decline. There are no significant differences in neuropsychiatric symptoms when comparing "pure" AD to AD with a significant vascular component. Conclusion: Neuropsychiatric symptoms such as frontal lobe symptoms, psychosis, agitation, aggression, and activity disturbances increase as dementia progresses. Affective symptoms such as anxiety and depressive symptoms, however, are more frequent in MCI than mild dementia but otherwise remain stable throughout the cognitive spectrum, except for an increase in CSDD score in severe dementia. There is no difference in neuropsychiatric symptoms when comparing mixed dementia (defined here as AD + significant cerebrovascular disease) to pure AD.