Cognitive declines precede and predict functional declines in aging and Alzheimer's disease

Evaluation of the Glymphatic System in Schizophrenia Spectrum Disorder Using Proton Magnetic Resonance Spectroscopy Measurement of Brain Macromolecule and Diffusion Tensor Image Analysis Along the Perivascular Space Index

BACKGROUND AND HYPOTHESIS

The glymphatic system (GS), a brain waste clearance pathway, is disrupted in various neurodegenerative and vascular diseases. As schizophrenia shares clinical characteristics with these conditions, we hypothesized GS disruptions in patients with schizophrenia spectrum disorder (SCZ-SD), reflected in increased brain macromolecule (MM) and decreased diffusion-tensor-image-analysis along the perivascular space (DTI-ALPS) index.

STUDY DESIGN

Forty-seven healthy controls (HCs) and 103 patients with SCZ-SD were studied. Data included 135 proton magnetic resonance spectroscopy (1H-MRS) sets, 96 DTI sets, with 79 participants contributing both. MM levels were quantified in the dorsal-anterior cingulate cortex (dACC), dorsolateral prefrontal cortex, and dorsal caudate (point resolved spectroscopy, echo-time = 35ms). Diffusivities in the projection and association fibers near the lateral ventricle were measured to calculate DTI-ALPS indices. General linear models were performed, adjusting for age, sex, and smoking. Correlation analyses examined relationships with age, illness duration, and symptoms severity.

STUDY RESULTS

MM levels were not different between patients and HCs. However, left, right, and bilateral DTI-ALPS indices were lower in patients compared with HCs (P < .001). In HCs, age was positively correlated with dACC MM and negatively correlated with left, right, and bilateral DTI-ALPS indices (P < .001). In patients, illness duration was positively correlated with dACC MM and negatively correlated with the right DTI-ALPS index (P < .05). In the entire population, dACC MM and DTI-ALPS indices showed an inverse correlation (P < .01).

CONCLUSIONS

Our results suggest potential disruptions in the GS of patients with SCZ-SD. Improving brain's waste clearance may offer a potential therapeutic approach for patients with SCZ-SD.

Together in sickness and in health: Spillover of physical, mental, and cognitive health among older English couples

Using data from eight waves of the English Longitudinal Study of Aging, we study the cross-domain and cross-spouse spillover of health among married adults aged 50 and above in England. We apply the system generalized method of moments to linear dynamic panel models for physical, mental, and cognitive health, controlling for individual heterogeneity and the influence of marriage market matching and shared environments. Our findings reveal bidirectional spillovers between memory abilities and mobility difficulty among men, as well as between depressive symptoms and mobility difficulty among women. Worsening mobility increases the risk of depression in men, but not vice versa. Additionally, gender-specific cross-spouse effects are observed. Women's mental health is significantly influenced by their spouse's mental health, while this effect is weaker for men. Conversely, men's mental health is notably affected by their spouse's physical health. These results highlight the importance of considering spillovers within families and across health domains when developing policies to promote health and reduce health disparities among the elderly population.

Do physical fitness and cognitive function mediate the relationship between basic activities of daily living and quality of life in older adults with dementia?

PURPOSE

Independence in activities of daily living (ADLs) is associated with quality of life (QoL) in individuals with dementia. However, the contribution of physical and cognitive functions to this relationship needs further examination. This study aims to examine the mediating effect of physical fitness and cognitive function in the relationship between independence in basic ADLs and QoL among older adults with dementia.

METHODS

This cross-sectional study included 107 older adults with dementia (74.8% women; age 78.21 ± 7.70 years). Independence in basic ADL and QoL were evaluated using the Barthel Index (BI) and QoL- Alzheimer's Disease Scale, respectively. The Alzheimer's Disease Assessment Scale-Cognitive Subscale and the Mini-Mental State Examination were applied to assess cognitive function. Physical fitness was evaluated using the 30-s chair stand, 2-min step and the Timed-Up and Go tests. A structural equation modelling (SEM) with bootstrapping estimation was conducted to determine the relationship between all variables.

RESULTS

Independence in basic ADL positively affected QoL and this association was mediated by physical fitness (β = 0.242, p = 0.011). No statistically significant results were observed when testing cognitive function as a mediator between BI and QoL (β = 0.009, p = 0.345).

CONCLUSIONS

Physical fitness (i.e., lower body strength, aerobic capacity, and mobility) plays a role in the relationship between basic ADL independence and QoL of older adults with dementia, reinforcing the need to improve and monitor these parameters throughout the disease progression. Future longitudinal studies should explore the temporal relationship between physical and cognitive function and its contribution to basic ADL independence and QoL.

Examining a Healthy Lifestyle as a Moderator of the Relationship between Psychological Distress and Cognitive Decline among Older Adults in the NuAge Study

INTRODUCTION

The objective of this study was to examine whether a healthy lifestyle composite score of social engagement, physical activity, and Mediterranean diet adherence moderates the association between psychological distress and global cognitive decline among cognitively healthy older adults (67+ years of age at baseline).

METHODS

A total of 1,272 cognitively intact older adults (Mage = 74.1 ± 4.1 years, 51.9% female) in the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge) completed a series of self-reported questionnaires to measure psychological distress and lifestyle behaviors, and the Modified Mini-Mental Examination (3MS) to assess cognitive performance at baseline and annually over 3 years.

RESULTS

Controlling for sociodemographic and health-related characteristics, greater psychological distress was associated with steeper cognitive decline over time among males (B = -0.07, 95% CI: [-0.12, -0.02]), but not females (B = 0.008, 95% CI: [0.03, 0.04]). Although a healthy lifestyle composite score did not statistically significantly moderate the distress-cognition relationship (B = -0.005, 95% CI: [-0.02, 0.01]), there was an association between higher psychological distress and greater cognitive decline at low levels of social engagement (B = -0.05, 95% CI: [-0.09, -0.006]), but not at high levels of social engagement (B = 0.02, 95% CI: [-0.03, 0.07]).

CONCLUSION

This study suggests that the potentially harmful impact of stress on cognitive function may be malleable through specific healthy lifestyle behaviors and emphasizes the importance of taking a sex-based approach to cognitive aging research.

Mediation of Post-Stroke Function by Cognition in the Canadian Longitudinal Study on Aging

INTRODUCTION

Cognitive and functional impairment after stroke are common, but the relation between cognitive and functional decline after stroke is not well studied.

METHODS

We used the comprehensive cohort in the Canadian Longitudinal Study on Aging to identify those with prior stroke, and we calculated reliable cognitive change scores from baseline to follow-up for the memory and executive domains. Functional decline was defined as an increase in the number of dependent daily activities. Using formal mediation analysis, we tested the presence and degree of mediation of the association between stroke and functional decline by cognitive decline.

RESULTS

There were 22,648 individuals with memory change scores (325 with stroke) and 17,613 individuals with executive change scores (241 with stroke). History of stroke was significantly associated with memory decline (-0.26 standard deviations, 95% CI -0.33 to -0.19), executive decline (-0.22, 95% CI -0.36 to -0.09), and new functional impairment (adjusted odds ratio 2.31, 95% CI 1.80-2.97) over a median of 3-year follow-up. Cognitive decline was a significant mediator of functional decline. Memory decline mediated only 5% of the relationship, whereas executive and overall cognitive decline mediated 13% and 22%, respectively.

CONCLUSION

Cognitive decline is a mediator of the association between prior stroke and functional decline; consequently, strategies to delay, attenuate, or prevent cognitive decline after stroke may be important to preserving long-term functional status.

Further evaluation of narrative description as a measure of cognitive function in Alzheimer's disease

OBJECTIVE

The narrative description (ND) test objectively measures the ability to understand and describe visual scenes. As subtle differences in speech occur early in cognitive decline, we analyzed linguistic features for their utility in detecting cognitive impairment and predicting downstream decline.

METHOD

Participants (n = 52) with normal cognition to mild dementia performed the ND test (watched twenty 30-s video clips and described the visual content). Cognitive function was followed for up to 5 years. We computed simple linguistic features such as content efficiency, speech rate, and part of speech and unique word counts. We examined (a) relationships between cognitive status and ND score and linguistic features; (b) ability to discriminate early cognitive impairment from normal cognition using ND score and linguistic features; and (c) whether ND score and linguistic features were associated with future cognitive functional decline.

RESULTS

Many of the linguistic-feature metrics were related to cognitive status. Many of the linguistic features could distinguish between the cognitively normal group and the mild cognitive impairment (MCI) and Dementia groups. The area under the curve (AUC) for ND score alone was 0.74, with a nonsignificant increase to 0.78 when adding mean word length. Among participants with subjective cognitive decline (SCD) at the first visit, a smaller number of words plus more interjections or a lower ND score at baseline were predictive of future cognitive decline.

CONCLUSIONS

While many linguistic features were associated with cognitive status, and some were able to detect early cognitive impairment or predictive of future cognitive decline, all the features we tested seem to have been captured by the ND score. Thus, adding linguistic measures to the ND test score did not add to its value in assessing current or predicting future cognitive status. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

GPR34 Knockdown Relieves Cognitive Deficits and Suppresses Neuroinflammation in Alzheimer's Disease via the ERK/NF-κB Signal

Alzheimer's disease (AD) is a serious neurodegenerative disease characterized by amyloid-β (Aβ) aggregation and neuroinflammation. G-protein-coupled receptor 34 (Gpr34) was found highly expressed in the hippocampus of APP/PS1 mice. However, its role in AD remains unclear. Herein, the role of Gpr34 as well as its molecular mechanism was explored. Data in GSE85162 were analyzed and the differently expressed genes in the hippocampus tissues of APP/PS1 mouse model of AD were subjected to GO, KEGG and GSEA enrichment analyses. APP/PS1 mice were used as an animal model of AD and the cognitive impairment was evaluated by a water maze test. The level of Gpr34 in hippocampus and BV-2 cells as well as the activation of ERK/NF-κB signal was determined by quantitative real-time PCR, western blot or immunofluorescence. Our results showed that, in BV-2 cells exposed to Aβ1-42, Gpr34 knockdown decreased the levels of TNF-α, IL-1β, IL-6 and iNOS and suppressed the activation of ERK/NF-κB signal. Moreover, the Gpr34-overexpression-induced activation of ERK/NF-κB signal and up-regulated levels of TNF-α, IL-1β, IL-6 and iNOS were abolished by FR180204, an ERK inhibitor. On the other hand, the in vivo study showed that Gpr34 knockdown ameliorated the cognitive impairment in APP/PS1 mice, decreased the levels of TNF-α, IL-1β and IL-6, the activation of microglia and ERK/NF-κB signal. In conclusion, Gpr34 knockdown relieved cognitive deficits in APP/PS1 mice and suppressed neuroinflammation and microglial activation, maybe via the ERK/NF-κB signal. It is indicated that the high level of Grp34 in hippocampus may contribute to the pathogenesis of AD.

Measures of physical performance as mediators between personality and cognition in two prospective studies

Few studies have examined the pathways linking personality to cognition. This study aimed to examine whether measures of physical performance (gait speed, peak expiratory flow (PEF), and grip strength) mediated the association between five-factor model personality traits and cognition (memory performance, subjective memory, and informant-rated cognition). Participants were aged 57 to 95 years from the Health and Retirement Study (HRS, N = 4,109) and the English Longitudinal Study of ageing (ELSA, N = 3,584). In HRS, personality and demographic factors were assessed in 2008/2010, physical performance in 2012/2014, and memory performance and subjective memory in 2016/2018. Informant-rated cognition was obtained in 2016 for an HRS subsample. In ELSA, personality and demographic factors were assessed in 2010/2011, physical performance in 2012/2013, and objective and subjective memory in 2014/2015. Informant-rated cognition was obtained in 2018 for an ELSA subsample. With a few exceptions, replicable patterns of mediation were found across HRS and ELSA. Slower gait speed partially mediated the association between higher neuroticism, lower conscientiousness and worse scores on all three cognitive measures (memory performance, subjective memory, and informant-rated cognition). Slower gait also partially mediated the association between openness and both objective and subjective memory. There was less replicable evidence for a mediating role of PEF and grip strength. The present study advances knowledge on the pathways linking personality to cognition in older adults and supports the hypothesis that personality associations with better physical function can help support healthy cognitive aging.

Association of Subjective Cognitive Decline With Progression to Dementia in a Cognitively Unimpaired Multiracial Community Sample

BACKGROUND AND OBJECTIVES

This prospective study seeks to examine the utility of subjective cognitive decline (SCD) as a marker of future progression to dementia in a community-based cohort of non-Latinx White, non-Latinx Black, and Latinx individuals. Debate surrounds the utility of SCD, the subjective perception of decline in one's cognition before such impairment is evident in traditional neuropsychological assessments, as an early indicator of impending Alzheimer disease. Unfortunately, most studies examining SCD have been conducted in non-Latinx White samples and commonly exclude groups of individuals shown to be most vulnerable to dementia.

METHODS

Participants were enrolled into this cohort study from the Washington Heights-Inwood Columbia Aging Project if they were cognitively unimpaired, had baseline measurement of SCD, and self-identified as non-Latinx White, non-Latinx Black, or Latinx. SCD was measured as a continuous sum of 10 items assessing cognitive complaints. Competing risk models tested the main effects of baseline SCD on progression to dementia. Models were adjusted for age, sex/gender, years of education, medical comorbidity burden, enrollment cohort, and baseline memory test performance with death jointly modelled as a function of race/ethnicity.

RESULTS

A total of 4,043 (1,063 non-Latinx White, 1,267 non-Latinx Black, and 1,713 Latinx) participants were selected for this study with a mean age of 75 years, 67% women, and with a mean follow-up of 5 years. Higher baseline SCD was associated with increased rates of incident dementia over time in the full sample (hazard ratio [HR] 1.085, CI 1.047-1.125, p < 0.001) and within Latinx (HR 1.084, CI 1.039-1.130, p < 0.001) and non-Latinx Black individuals (HR 1.099, CI 1.012-1.194, p = 0.024).

DISCUSSION

Overall results of this study support SCD as a prodromal marker of dementia in a multiracial community sample, and in Latinx and non-Latinx Black individuals in particular. Because models examining the risk of dementia were adjusted for baseline memory test performance, the results support the idea that SCD, a subjective reflection of one's own current cognitive functioning, contributes information above and beyond standard memory testing. Current findings highlight the importance of carefully evaluating any memory concerns raised by older adults during routine visits and underscore the potential utility of screening older adults for SCD.

The mediating role of Vitamin D in the association between personality and memory: Evidence from two samples

Five-Factor Model (FFM) personality traits are consistently related to cognition in old age. However, little is known about the biological mediators of this association. The present study examined whether levels of Vitamin D mediated the association between personality and memory. Participants were adults aged 50-96 years from the Health and Retirement Study (HRS, N = 5229) and the English Longitudinal Study of Ageing (ELSA, N = 4249). In HRS, personality and demographic factors were assessed in 2012/2014, Vitamin D was assessed in 2016, and memory was assessed in 2018. In ELSA, personality and demographic factors were obtained in 2010/2011, Vitamin D was measured in 2012/2013, and memory was assessed in 2014/2015. In both samples, higher extraversion and conscientiousness were related to higher levels of Vitamin D, whereas higher neuroticism was related to lower Vitamin D. In both samples, higher Vitamin D partly mediated the association between both higher extraversion and conscientiousness and better memory. The association between higher neuroticism and worse memory at follow-up was partially mediated by lower Vitamin D in the HRS and ELSA. Vitamin D did not mediate the association between higher openness and better memory. The present study extends the personality-cognition literature by providing new replicable evidence that Vitamin D is a biological mediator.

The Mediating Role of Biomarkers in the Association Between Subjective Aging and Episodic Memory

OBJECTIVES

Subjective aging, indexed by subjective age and self-perceptions of aging (SPA), is consistently related to cognition in adulthood. The present study examined whether blood biomarkers mediate the longitudinal associations between subjective aging indices and memory.

METHODS

Data of 5,369 individuals aged 50-94 years (mean = 66.89 years, SD = 9.22; 60% women) were drawn from the Health and Retirement Study (HRS). Subjective age, SPA, and demographic factors were assessed in 2012/2014. Interleukin-6, C-reactive protein, albumin, cystatin C, N-terminal pro B-type natriuretic peptide (NT-proBNP), fasting glucose, Vitamin D, hemoglobin, red cells distribution width, and epigenetic aging were assessed as part of the HRS Venuous Blood Study in 2016. Memory was measured in 2018. The mediators (except for epigenetic aging, which was assessed in a subsample) were tested simultaneously in models that accounted for demographic covariates.

RESULTS

An older subjective age was related to worse memory partially through higher fasting glucose, higher cystatin C, higher NT-proBNP, and accelerated epigenetic aging. Negative SPA was related to worse memory through lower Vitamin D3, higher fasting glucose, higher cystatin C, higher NT-proBNP, and accelerated epigenetic aging. The biomarkers explained between 2% and 10% of subjective age and between 1% and 8% of SPA associations with memory. Additional analysis revealed that biomarkers continued to be significant mediators when physical inactivity and depressive symptoms were included as additional mediators.

CONCLUSION

The present study adds to existing research on the association between subjective aging and memory by providing new evidence on the biological mediators of this association.

Integration of GWAS and brain transcriptomic analyses in a multiethnic sample of 35,245 older adults identifies DCDC2 gene as predictor of episodic memory maintenance

Identifying genes underlying memory function will help characterize cognitively resilient and high-risk declining subpopulations contributing to precision medicine strategies. We estimated episodic memory trajectories in 35,245 ethnically diverse older adults representing eight independent cohorts. We conducted apolipoprotein E (APOE)-stratified genome-wide association study (GWAS) analyses and combined individual cohorts' results via meta-analysis. Three independent transcriptomics datasets were used to further interpret GWAS signals. We identified DCDC2 gene significantly associated with episodic memory (Pmeta = 3.3 x 10^-8 ) among non-carriers of APOE ε4 (N = 24,941). Brain transcriptomics revealed an association between episodic memory maintenance and (1) increased dorsolateral prefrontal cortex DCDC2 expression (P = 3.8 x 10^-4 ) and (2) lower burden of pathological Alzheimer's disease (AD) hallmarks (paired helical fragment tau P = .003, and amyloid beta load P = .008). Additional transcriptomics results comparing AD and cognitively healthy brain samples showed a downregulation of DCDC2 levels in superior temporal gyrus (P = .007) and inferior frontal gyrus (P = .013). Our work identified DCDC2 gene as a novel predictor of memory maintenance.

Toward the optimized assessment of clinical outcomes in studies of novel treatments for Alzheimer's disease

INTRODUCTION

Alzheimer's disease (AD) is characterized by a progressive decline in cognition and daily function, leading to a greater need for caregiver support. Clinical disease is segmented into a preclinical stage, mild cognitive impairment, and mild, moderate, and severe stages of Alzheimer's dementia. Although AD trials enroll participants at various stages of illness, treatment efficacy is often assessed using endpoints based on measures of outcomes that are held fixed across disease stages. We hypothesize that matching the primary outcomes measured in the endpoint hierarchy to the stage of disease targeted by the trial will increase the likelihood of detecting true treatment benefits.

AREAS COVERED

We discuss current approaches to assessing clinical outcomes in AD trials, followed by a consideration of how effect detection can be improved by linking the stage of AD to the endpoints that most likely reflect stage-specific disease progression.

EXPERT OPINION

Failing to account for stage-specific relevance and sensitivity of clinical outcomes may be one factor that contributes to trial failures in AD. Given the history of failure, experts have begun to scrutinize the relevance and sensitivity of outcomes as a potentially modifiable barrier to successful trials. To this end, we present a framework for refining trial endpoint selection and evaluation.

Bidirectional relationship between cognitive function and loss hierarchy of activities of daily living among older adults with disabilities in urban China: a cross-lagged analysis

OBJECTIVES

The present study aimed to determine the bidirectional relationship between cognitive function and the loss hierarchy of activities of daily living (ADL) among older adults in China.

DESIGN

Data were derived from the Longitudinal Study on Family Caregivers for Frail Older Adults Aged 75 or Above in Shanghai (2010-2013).

SETTING

Community-dwelling older adults and their primary caregivers were invited to participate in this research.

PARTICIPANTS

The inclusion criteria for the older adults were as follows: (a) have a Shanghai urban household registration status, (b) be 75 years old or older, (c) have no fewer than two limitations in ADLs or equivalent, and (d) have one primary caregiver aged 18 years or older. 469 older adults cared by their spouses or children were included in the final analytical sample of this research.

PRIMARY AND SECONDARY OUTCOME MEASURES

Cognitive function was assessed using the Chinese version of the Short Portable Mental Status Questionnaire and ADLs were measured by self-reports of having difficulty or needing help with basic daily activities.

RESULTS

Cognitive function in 2010 was a significant predictor of intermediate loss of ADLs in 2013 (β=-0.13, p<0.05) and late loss of ADLs in 2013 (β=-0.17, p<0.01). The loss hierarchy of ADLs among older adults was not shown to be significant as a risk factor of cognitive function in 2013.

CONCLUSIONS

Practitioners are encouraged to adopt the ADL loss hierarchy as a supplementary needs assessment tool to make the social service delivery process more effective, economical and tailored. Cognitive function change monitoring programmes and services providing education on nutrition and encouraging social participation of older individuals were also helpful in promoting the quality of life of the older adults.

Predictors of Incident Mild Cognitive Impairment and Its Course in a Diverse Community-Based Population

BACKGROUND AND OBJECTIVES

To investigate sociodemographic and medical predictors of incident mild cognitive impairment (MCI) and subsequent course of MCI at follow-up, including sustained MCI diagnosis, classification as cognitively normal, and progression to dementia.

METHODS

Within a community-based cohort, diagnoses of MCI were made with a published algorithm. Diagnosis of dementia was based on clinical consensus. Cox regressions estimated hazard ratios of incident MCI associated with several predictors. Modified Poisson regressions estimated relative risks associated with predictors of diagnostic status at follow-up after incidence.

RESULTS

Among 2,903 cognitively normal participants at baseline, 752 developed MCI over an average of 6.3 (SD 4.5) years (incidence rate 56 per 1,000 person-years). Presence of APOE ε4 and higher medical burden increased risk of incident MCI, while more years of education, more leisure activities, and higher income decreased this risk. Of the incident MCI cases, after an average of 2.4 years of follow-up, 12.9% progressed to dementia, 9.6% declined in functioning and did not meet the algorithmic criteria for MCI but did not meet the clinical criteria for dementia, 29.6% continued to meet MCI criteria, and 47.9% no longer met MCI criteria. Multidomain MCI, presence of APOE ε4, depressive symptoms, and antidepressant use increased the risk of progression to dementia.

DISCUSSION

This community-based study showed that almost half of the individuals with incident MCI diagnoses were classified as cognitively normal at follow-up. Predictors of incident MCI demonstrably differed from those of subsequent MCI course; these findings can refine expectations for cognitive and functional course of those presenting with MCI.

Gender-specified mediation of depression between sleep quality and short-term memory in older adults: Study in a semi-closed Island of Xiamen, China

BACKGROUND

Both the quality of sleep and depression impact short-term memory (STM) while they influence each other. However, the underlying mechanisms are not yet clear. Herein, we aimed to explore the mediating effect of depression between sleep quality and STM in older adults and further test the gender differences in this relationship.

METHODS

A cluster sampling survey was carried out among 903 residents that were aged 60+ years in a semi-closed island of Xiamen, China, in 2019. The subjects' sleep quality and depression were measured using the Pittsburgh Sleep Quality Index (PSQI) and the 15-item Geriatric Depression Scale (GDS-15), respectively. The three-item recall test was utilized to measure STM function. Mediation analyses were performed using the structural equation model and bias-corrected bootstrap method. Next, the Wald-test was utilized to determine gender differences in the pathway.

RESULTS

Overall, 355 men and 508 women, with a mean age of 69.55 and 70.97, respectively, had valid data on the main variables. Depression was found to mediate the effect of sleep quality on STM (a*b = -0.076, p < 0.05). Interestingly, while this indirect effect existed in the female group (a_f *b_f  = -0.126, p < 0.05), it did not in the male group (a_m *b_m  = 0.017, p = 0.677). The Wald-test indicated no gender differences in the pathway from sleep quality to depression (p = 0.303). However, the pathway from depression to STM function was found to be significantly stronger for females than males (p = 0.0198).

CONCLUSION

Higher sleep quality was found to be associated with improved STM function. Furthermore, the association was found to be regulate indirectly by lower depressive symptoms for females, but directly for males. Therefore, appropriate psychological interventions may be beneficial to the maintenance of STM for older adults, particularly for women.

TNF-α-dependent neuronal necroptosis regulated in Alzheimer's disease by coordination of RIPK1-p62 complex with autophagic UVRAG

Background: Neuronal death is a major hallmark of Alzheimer's disease (AD). Necroptosis, as a programmed necrotic process, is activated in AD. However, what signals and factors initiate necroptosis in AD is largely unknown. Methods: We examined the expression levels of critical molecules in necroptotic signaling pathway by immunohistochemistry (IHC) staining and immunoblotting using brain tissues from AD patients and AD mouse models of APP/PS1 and 5×FAD. We performed brain stereotaxic injection with recombinant TNF-α, anti-TNFR1 neutralizing antibody or AAV-mediated gene expression and knockdown in APP/PS1 mice. For in vitro studies, we used TNF-α combined with zVAD-fmk and Smac mimetic to establish neuronal necroptosis models and utilized pharmacological or molecular biological approaches to study the signaling pathways. Results: We find that activated neuronal necroptosis is dependent on upstream TNF-α/TNFR1 signaling in both neuronal cell cultures and AD mouse models. Upon TNF-α stimulation, accumulated p62 recruits RIPK1 and induces its self-oligomerization, and activates downstream RIPK1/RIPK3/MLKL cascade, leading to neuronal necroptosis. Ectopic accumulation of p62 is caused by impaired autophagy flux, which is mediated by UVRAG downregulation during the TNF-α-promoted necroptosis. Notably, UVRAG overexpression inhibits neuronal necroptosis in cell and mouse models of AD. Conclusions: We identify a finely controlled regulation of neuronal necroptosis in AD by coordinated TNF-α signaling, RIPK1/3 activity and autophagy machinery. Strategies that could fine-tune necroptosis and autophagy may bring in promising therapeutics for AD.

Longitudinal trajectories of physical functioning among Chinese older adults: the role of depressive symptoms, cognitive functioning and subjective memory

BACKGROUND AND OBJECTIVE

Maintaining physical functioning (i.e. mobility, activities of daily living [ADLs], instrumental activities of daily living [IADLs]) in older adults is essential for independent living. However, little is known about how longitudinal trajectories of physical functioning differ by varying levels of depressive symptoms, subjective memory impairment and cognitive functioning. We aimed to examine whether, and to what degree, the rate of change in physical functioning over time was associated with depressive symptoms, subjective memory and cognitive functioning.

DESIGN

A correlational longitudinal design.

METHODS

The sample included 5,519 older adults (mean age = 68.13 years) from the China Health and Retirement Longitudinal Study (three waves: 2011-15) who self-reported their depressive symptoms, subjective memory impairment and physical functioning. Cognitive functioning was assessed through interview-based tests.

RESULTS

There were significant increases in mobility impairment (β = 0.27, P < 0.001), ADLs impairment (β = 0.05, P < 0.001) and IADLs impairment (β = 0.03, P = 0.006) over time. Compared with the mean score at baseline in 2011, the mobility, ADLs and IADLs impairment increased by 13.32, 10.57 and 4.34% for every 2 years, respectively. Those with high depressive symptoms had accelerated rates of mobility (β = 0.212, P < 0.001), ADLs (β = 0.104, P < 0.001) and IADLs impairment (β = 0.076, P = 0.002). Those with poorer cognitive functioning had more rapid rates of mobility impairment. In contrast, those with differing levels of subjective memory impairment did not experience different physical functioning trajectories.

CONCLUSIONS

High depressive symptoms and poor cognitive functioning may be precursors to rapid declines in physical functioning. Proactive screening for these precursors may attenuate physical decline among Chinese older adults.

Dynamic reciprocal relationships between cognitive and functional declines along the Alzheimer's disease continuum in the prospective COGICARE study

BACKGROUND

Thoroughly understanding the temporal associations between cognitive and functional dimensions along the dementia process is fundamental to define preventive measures likely to delay the disease's onset. This work aimed to finely describe the trajectories of cognitive and functional declines, and assess their dynamic bidirectional relationships among subjects at different stages of the dementia process.

METHODS

We leveraged extensive repeated data of cognition and functional dependency from the French prospective COGICARE study, designed to better characterize the natural history of cognitive and functional declines around dementia diagnosis. Cognition was measured by the Mini-Mental State Examination, the Isaacs Set Test for verbal fluency, the Benton Visual Retention Test for visuo-spatial memory, and Trail Making Test Part B for executive functioning. Functional dependency was measured by basic and instrumental activities of daily living. The study included 102 cognitively normal, 123 mildly cognitively impaired, and 72 dementia cases with a median of 5 repeated visits over up to 57 months. We used a dynamic causal model which addresses the two essential issues in temporal associations assessment: focusing on intra-individual change and accounting for time.

RESULTS

Better cognitive abilities were associated with lower subsequent decline of the functional level among the three clinical stages with an intensification over time but no reciprocity of the association whatever the clinical status.

CONCLUSION

This work confirms that the progressive functional dependency could be induced by cognitive impairment. Subjects identified as early as possible with clinically significant cognitive impairments could benefit from preventive measures before the deterioration of activities of daily living and the appearance of dementia clinical signs.

Classification, Prediction, and Concordance of Cognitive and Functional Progression in Patients with Mild Cognitive Impairment in the United States: A Latent Class Analysis

Background:

Progression trajectories of patients with mild cognitive impairment (MCI) are currently not well understood.

Objective:

To classify patients with incident MCI into different latent classes of progression and identify predictors of progression class.

Methods:

Participants with incident MCI were identified from the US National Alzheimer’s Coordinating Center Uniform Data Set (09/2005-02/2019). Clinical Dementia Rating (CDR^®) Dementia Staging Instrument-Sum of Boxes (CDR-SB), Functional Activities Questionnaire (FAQ), and Mini-Mental State Examination (MMSE) score longitudinal trajectories from MCI diagnosis were fitted using growth mixture models. Predictors of progression class were identified using multivariate multinomial logistic regression models; odds ratios (ORs) and 95% confidence intervals (CIs) were reported.

Results:

In total, 21%, 22%, and 57% of participants (N = 830) experienced fast, slow, and no progression on CDR-SB, respectively; for FAQ, these figures were 14%, 23%, and 64%, respectively. CDR-SB and FAQ class membership was concordant for most participants (77%). Older age (≥86 versus≤70 years, OR [95% CI] = 5.26 [1.78–15.54]), one copy of APOE ɛ4 (1.94 [1.08–3.47]), higher baseline CDR-SB (2.46 [1.56–3.88]), lower baseline MMSE (0.85 [0.75–0.97]), and higher baseline FAQ (1.13 [1.02–1.26]) scores were significant predictors of fast progression versus no progression based on CDR-SB (all p < 0.05). Predictors of FAQ class membership were largely similar.

Conclusion:

Approximately a third of participants experienced progression based on CDR-SB or FAQ during the  4-year follow-up period. CDR-SB and FAQ class assignment were concordant for the vast majority of participants. Identified predictors may help the selection of patients at higher risk of progression in future trials.

Physical Activity in Early- and Mid-Adulthood Are Independently Associated With Longitudinal Memory Trajectories in Later Life

BACKGROUND

Physical activity (PA) in later life may reduce dementia risk, but little is known regarding long-term cognitive effects of PA that occurred earlier in adulthood or mechanisms underlying associations. PA patterns at different ages may independently contribute to dementia risk, which would implicate multiple critical periods for intervention. The current study tested whether retrospective reports of PA in early and mid-adulthood were independently associated with later-life longitudinal memory outcomes and whether associations were mediated by late-life cardiometabolic diseases.

METHOD

Participants comprised 5200 Health and Retirement Study Life History Mail Survey respondents. Latent growth curves estimated independent associations between retrospectively reported PA in early adulthood (age 18-29) and mid-adulthood (age 40-49) and 16-year episodic memory trajectories. Indirect pathways involving the maintenance of PA from early- to mid-adulthood and the influence of PA on later-life cardiometabolic diseases (hypertension, diabetes, and heart disease) were also estimated.

RESULTS

PA in early- and mid-adulthood independently predicted higher initial memory level and slower memory decline in later life, respectively. Early-adulthood PA was indirectly associated with later-life memory level through higher mid-adulthood PA and lower rates of later-life hypertension, as well as with subsequent memory decline through higher mid-adulthood PA.

CONCLUSIONS

The current findings highlight the importance of PA throughout adulthood, such that initiating and/or maintaining exercise in early- or mid-adulthood may be protective for later-life cognitive health, and hypertension appears to represent a key mediator of these effects.

Memory and Personality Development in Adulthood: Evidence From Four Longitudinal Studies

OBJECTIVES

Personality traits have been related to concurrent memory performance. Most studies, however, have focused on personality as a predictor of memory; comparatively less is known about whether memory is related to personality development across adulthood. Using 4 samples, the present study tests whether memory level and change are related to personality change in adulthood.

METHOD

Participants were drawn from 2 waves of the Wisconsin Longitudinal Study Graduates (WLSG; N = 3,232, mean age = 64.28, SD = 0.65) and Wisconsin Longitudinal Study Siblings (WLSS; N = 1,570, mean age = 63.52, SD = 6.69) samples, the Midlife in the United States (MIDUS; N = 1,901, mean age = 55.43, SD = 10.98), and the Health and Retirement Study (HRS; N = 6,038, mean age = 65.47, SD = 8.28). Immediate and delayed recall and the 5 major personality traits were assessed at baseline and follow-up.

RESULTS

There was heterogeneity in the associations across samples. A meta-analysis of latent change in the four samples indicated that lower baseline memory performance was related to an increase in neuroticism (B = -0.002; 95% CI = -0.004, -0.0008) and a decrease in agreeableness (B = 0.004; 95% CI = 0.002, 0.007) and conscientiousness (B = 0.005; 95% CI = 0.0008, 0.010). In addition, declines in memory were related to steeper declines in extraversion (B = 0.06; 95% CI = 0.003, 0.11), openness (B = 0.04; 95% CI = 0.007, 0.069), and conscientiousness (B = 0.05; 95% CI = 0.019, 0.09).

DISCUSSION

The present study indicates that poor memory and declines in memory over time are related to maladaptive personality change. These associations, however, were small and inconsistent across samples.

Beneficial Effects of Physical Activity on Subjects with Neurodegenerative Disease

Studies on the effectiveness of physical exercise to treat and/or prevent mental disorders are essential and particularly appropriate, given the rapid growth of the elderly population and the consequent increase in the prevalence of neurodegenerative diseases. The onset of neurodegenerative diseases is subtle, and progression is irreversible, as there is still no cure capable of stopping them permanently. Therefore, we should not underestimate these diseases and should immediately begin to combine the treatment with physical activity adapted to specific needs. Indeed, it is well known that physical activity has positive effects on mobility, autonomy, and functional capacity, improving not only cognitive functions, but also reducing the risk of developing dementia. Despite several studies in this field, to date there are no specific and effective protocols that promote physical exercise in people with dementia. Based on this evidence, the aim of the present work was to verify whether an adapted physical exercise regimen could promote the maintenance of psychomotor functions in elderly subjects and, therefore, delay the irreversible effects of combinations of dementia and other pathologies associated with aging. Our results clearly show that exercise is very effective in improving psychomotor functions and delaying the progress of neurodegenerative diseases in humans, since we observed that the subjects maintained their cognitive skills after 8 months of physical activity, moreover, two patients presented an amelioration. Based on the results obtained, we recommend that the motor practice, in any chosen form, be considered an integral part of prevention programs based on an active lifestyle in older people. Future studies will be necessary to establish how long lasting the benefits of a specific physical activity are and whether they are enough to delay cognitive decline.

The Quick Physical Activity Rating (QPAR) scale: A brief assessment of physical activity in older adults with and without cognitive impairment

INTRODUCTION

Alzheimer's disease and related dementias (ADRD) currently affect over 5.7 million Americans and over 35 million people worldwide. At the same time, over 31 million older adults are physically inactive with impaired physical performance interfering with activities of daily living. Low physical activity is a risk factor for ADRD. We examined the utility of a new measure, the Quick Physical Activities Rating (QPAR) as an informant-rated instrument to quantify the dosage of physical activities in healthy controls, MCI and ADRD compared with Gold Standard assessments of objective measures of physical performance, fitness, and functionality.

METHODS

This study analyzed 390 consecutive patient-caregiver dyads who underwent a comprehensive evaluation including the Clinical Dementia Rating (CDR), mood, neuropsychological testing, caregiver ratings of patient behavior and function, and a comprehensive physical performance and gait assessment. The QPAR was completed prior to the office visit and was not considered in the clinical evaluation, physical performance assessment, staging or diagnosis of the patient. Psychometric properties including item variability and distribution, floor and ceiling effects, strength of association, known-groups performance, and internal consistency were determined.

RESULTS

The patients had a mean age of 75.3±9.2 years, 15.7±2.8 years of education and were 46.9% female. The patients had a mean CDR-SB of 4.8±4.7 and a mean MoCA score of 18.6±7.1 and covered a range of healthy controls (CDR 0 = 54), MCI or very mild dementia (CDR 0.5 = 161), mild dementia (CDR 1 = 92), moderate dementia (CDR 2 = 64), and severe dementia (CDR 3 = 29). The mean QPAR score was 20.2±18.9 (range 0-132) covering a wide range of physical activity. The QPAR internal consistency (Cronbach alpha) was very good at 0.747. The QPAR was correlated with measures of physical performance (dexterity, grip strength, gait, mobility), physical functionality rating scales, measures of activities of daily living and comorbidities, the UPDRS, and frailty ratings (all p < .001). The QPAR report of physical activities was able to discriminate between individuals with impaired physical functionality (32.2±23.9 vs 15.2±13.8, p < .001), falls risk (28.4±21.6 vs. 14.5±13.2, p < .001), and the presence of frailty (28.1±22.7 vs. 11.8±9.4, p < .001). The QPAR showed strong psychometric properties and excellent data quality, and worked equally well across different patient ages, sexes, informant relationships, and in individuals with and without cognitive impairment.

DISCUSSION

The QPAR is a brief detection tool that captures informant reports of physical activities and differentiates individuals with normal physical functionality from those individuals with impaired physical functionality. The QPAR correlated with Gold Standard assessments of strength and sarcopenia, activities of daily living, gait and mobility, fitness, health related quality of life, frailty, global physical performance, and provided good discrimination between states of physical functionality, falls risk, and frailty. The QPAR performed well in comparison to standardized scales of objective physical performance, but in a brief fashion that could facilitate its use in clinical care and research.

Modelling Decline in Cognition to Decline in Function in Alzheimer's Disease

OBJECTIVES

The study aimed to evaluate and quantify the temporal link between cognitive and functional decline, and assess the impact of the apolipoprotein E4 (APOE-e4) genotype on Alzheimer's disease (AD) progression.

METHODS

A nonlinear mixed-effects Emax model was developed using longitudinal data from 659 patients with dementia due to AD sourced from the Alzheimer's disease neuroimaging initiative (ADNI) database. A cognitive decline model was first built using a cognitive subscale of the AD assessment scale (delayed word recall) as the endpoint, followed by a functional decline model, using the functional assessment questionnaire (FAQ) as the endpoint. Individual and population cognitive decline from the first model drove a functional decline in the second model. The impact of the APOE-e4 genotype status on the dynamics of AD progression was evaluated using the model.

RESULTS

Mixed-effects Emax models adequately quantified population average and individual disease trajectories. The model captured a higher initial cognitive impairment and final functional impairment in APOE-e4 carriers than non-carriers. The age at cognitive decline and diagnosis of dementia due to AD was significantly lower in APOE-e4 carriers than that of non-carriers. The average [standard deviation] time shift between cognitive and functional decline, i.e. the time span between half of the maximum cognitive decline and half of the maximum functional decline, was estimated as 1.5 [1.6] years.

CONCLUSION

The present analysis quantifies the temporal link between a cognitive and functional decline in AD progression at the population and individual level, and provides information about the potential benefits of pre-clinical AD treatments on both cognition and function.

The effectiveness of dance interventions on cognition in patients with mild cognitive impairment: A meta-analysis of randomized controlled trials

This meta-analysis of randomized controlled trials (published or unpublished RCTs in English) examined the effectiveness of dance interventions compared to waitlist/active controls on cognitive functions in patients with mild cognitive impairment (MCI). Literature search was conducted on MEDLINE, EMBASE, CINAHL and related databases through 3 August 2019. Risk of bias was assessed with the PEDro scale regarding randomization, allocation concealment, group comparability, blinding, attrition and selective reporting. Five included RCTs (N = 358) used Latin, ballroom and aerobic dances (frequency: 1-3 session/week; intensity: light to moderate; time: 25-60 min/session; type: aerobic). Results show that dance interventions improve global cognition (SMD [95 % CI] = 0.48 [0.21, 0.74]), attention (SMD [95 % CI] = 0.33 [0.12, 0.54]), immediate (SMD [95 % CI] = 0.54 [0.38, 0.71]) and delayed recall (SMD [95 % CI] = 0.33 [0.01, 0.64]), and visuospatial ability (SMD [95 % CI] = 0.16 [0.01, 0.32]). Study limitations include a small number of RCTs and high heterogeneity in some cognitive domains. In summary, dance interventions improve some cognitive domains in MCI. (PROSPERO registration: CRD42019145418).

Daily functioning and dementia

Dementia is characterized by a decline in memory, language, problem-solving and in other cognitive domains that affect a person's ability to perform everyday activities and social functioning. It is consistently agreed that cognitive impairment is an important risk factor for developing functional disabilities in patients with dementia. Functional status can be conceptualized as the ability to perform self-care, self- maintenance and physical activity. A person with dementia usually requires help with more complex tasks, such as managing bills and finances, or simply maintaining a household. Good functional performance is fundamental for elderly people to maintain independency and avoid institutionalization. The purpose of this review is to describe functional changes in demented patients, evaluating the variability in subgroups of dementias.

Potential Benefits of Physical Activity in MCI and Dementia

Physical activity improves overall health and reduces the risk of many negative health outcomes and may be effective in improving cognition, independent functioning, and psychological health in older adults. Given the evidence linking physical activity with improvements in various aspects of health and functioning, interventions exploring pathways for decreasing risk of dementia in those with mild cognitive impairment (MCI) and improving outcomes for those with dementia are of critical importance. The present review highlights the work examining physical activity interventions in order to achieve a comprehensive understanding of the potential benefits of physical activity for individuals experiencing cognitive decline. The primary focus is on aerobic exercise as this is the main intervention in the literature. Our review supports the thesis that physical activity can promote healthy aging in terms of cognition, independent functioning, and psychological health for individuals experiencing cognitive decline. Specifically, physical activity improves cognition, especially executive functioning and memory in MCI, independent functioning in MCI and dementia, and psychological health in dementia. Given that benefits of physical activity have been observed across these domains, such interventions provide an avenue for preventing decline and/or mitigating impairment across several domains of functioning in older adults with MCI or dementia and may be recommended (and adjusted) for patients across a range of settings, including medical and mental health settings. Further implications for clinical intervention and future directions for research are discussed.

Cognition and Daily Functioning: Results from the Hispanic Community Health Study/Study of Latinos (SOL) and Study of Latinos-Investigation of Neurocognitive Aging (SOL-INCA)

BACKGROUND

Among older adults, poorer cognitive functioning has been associated with impairments in instrumental activities of daily living (IADLs). However, IADL impairments among older Hispanics/Latinos is poorly understood.

OBJECTIVE

To characterize the relationships between cognition and risk for IADL impairment among diverse Hispanics/Latinos.

METHODS

Participants included 6,292 community-dwelling adults from the Study of Latinos - Investigation of Neurocognitive Aging, an ancillary study of 45+ year-olds in the Hispanic Community Health Study/Study of Latinos. Cognitive data (learning, memory, executive functioning, processing speed, and a Global cognitive composite) were collected at Visit 1. IADL functioning was self-reported 7 years later, and treated as a categorical (i.e., risk) and continuous (i.e., degree) measures of impairment. Survey two-part models (mixture of logit and generalized linear model with Gaussian distribution) and ordered logistic regression tested the associations of cognitive performance (individual tests and composite z-score) with IADL impairment. Additionally, we investigated the moderating role of age, sex, and Hispanic/Latino background on the association between cognition and IADL impairment.

RESULTS

Across all cognitive measures, poorer performance was associated with higher odds of IADL impairment 7 years later. Associations were generally stronger for the oldest group (70+ years) relative to the youngest group (50-59 years). Sex and Hispanic/Latino background did not modify the associations. Across the full sample, lower scores on learning, memory, and the Global cognitive composite were also associated with higher degree of IADL impairment.

CONCLUSION

Across diverse Hispanics/Latinos, cognitive health is an important predictor of everyday functioning 7 years later, especially in older adulthood.

'Feeling younger, remembering better': the effect of experimentally induced subjective age on memory performance among Chinese older adults

Objectives: This study aimed to explore whether experimentally induced younger subjective age can lead to better memory performance among Chinese older adults.Method: A total of 203 participants aged 60-84 years were randomly assigned to three groups. In the positive and neutral feedback groups, participants were told that their memory performance was better than and equivalent to the same-aged peers after an initial memory task, respectively, in contrast to no feedback in the control group. Participants then completed a second memory measure.Results: The results revealed that participants in the positive feedback group felt younger and showed a significant increase in memory performance, whereas participants in the neutral feedback group felt older but also showed a significant increase in memory performance. For participants in the control group, no significant changes in memory performance were observed.Conclusion: It seems that experimentally induced younger subjective age can lead to better memory performance among older adults, providing a promising strategy to maintain memory functioning in old age.

Temporal precedence of cognitive function and functional abilities: A latent difference score model of the Chinese community-dwelling elders

OBJECTIVES

Little research has explored how cognitive function and activities of daily living (ADL) affect each other over time. In addition, no current finding provides a clear hint to the temporal precedence between them. The present study tries to address these limitations of prior studies by utilizing a longitudinal data and advanced statistical modeling.

METHODS

This study analyzed the data from the China Health and Retirement Longitudinal Study (CHARLS), a prospective observational study performed every 2 years for a total of three waves between 2011 and 2015 using a multistage probability sampling. Cognitive function was measured on the basis of three aspects of cognitive performance. Functional abilities were assessed using six types of activities of ADL and five types of instrumental ADL (IADL). Latent difference score modeling was employed to investigate the temporal precedence between cognitive function and ADL.

RESULTS

The best fitting model indicates poor cognitive function precede worsening in ADL function, whereas the current findings did not support that poor ADL predate the cognition decline or reciprocal influence hypotheses.

CONCLUSIONS

The elderly with poor cognitive function may be more vulnerable to deterioration in ADL. Findings underscore the importance of early screening for cognitive function among the elderly as the key strategy to prevent further ADL impairment and keep independence.

Blood Pressure Variability and Progression of Clinical Alzheimer Disease

Blood pressure variability (BPV) has been shown to have predictive value over blood pressure (BP) levels alone in stroke patients. We assessed whether BPV predicts cognitive and functional decline in Alzheimer disease, using data from a randomized trial (NILVAD [A European Multicentre Double-blind Placebo-controlled Phase III Trial of Nilvadipine in Mild to Moderate Alzheimer’s Disease]). Patients with mild-to-moderate Alzheimer disease were included if they had ≥3 office BP measurements available to determine visit-to-visit BPV. Day-to-day BPV was assessed using home BP measurements in a subsample. The variation independent of mean was used to calculate BPV. Outcomes were change in Alzheimer’s Disease Assessment Scale–cognitive subscale-12 and Disability Assessment for Dementia after 1 and 1.5 years. A total of 460 patients aged 72.1 (SD=8.1) years, with mean BP of 134.0/75.1 (10.9/6.3) mm Hg were included. After 1 year, patients in the highest quartile of BPV had deteriorated more on Alzheimer’s Disease Assessment Scale–cognitive subscale compared with patients in the lowest quartile (systolic: β, 2.24 [95% CI, 0.11–4.38], P =0.040; diastolic: β, 2.54 [95% CI, 0.33–4.75] P =0.024). This association was still present after 1.5 years (systolic: β, 2.86 [95% CI, 0.35–5.36], P =0.026; diastolic: β, 3.30 [95% CI, 0.67–5.93], P =0.014). There was no effect of visit-to-visit BPV on Disability Assessment for Dementia. Day-to-day BPV was available for 46 patients. Significant associations were observed between day-to-day BPV and deterioration on Alzheimer’s Disease Assessment Scale–cognitive subscale (systolic: P =0.036) and Disability Assessment for Dementia (systolic: P =0.020; diastolic: P =0.007) after 1 year, but not after 1.5 years. All associations were adjusted for potential confounders, including intervention group. In conclusion, this post hoc analysis indicates that higher visit-to-visit and day-to-day BPV might be associated with progression of Alzheimer disease. Targeting BPV may be a future target to slow decline in patients with Alzheimer disease.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02017340.

Subjective Age and Memory Performance Among Older Chinese Adults : A Moderated Mediation Model

This study aims to examine the mediating role of learning self-efficacy in the relationship between subjective age and memory performance as well as the moderating role of education in these indirect and direct relationships. A study was conducted with 200 older adults aged 60 to 81 years who completed measures of subjective age, learning self-efficacy, education, and memory performance. Analysis revealed that learning self-efficacy partially mediated the association between subjective age and memory performance. Further analysis found that the indirect associations between subjective age and memory through learning self-efficacy vary as a function of education. Implications and suggestions for future research are discussed.

Subjective Cognitive Decline and APOE ɛ4: A Systematic Review

Individuals with subjective cognitive decline (SCD) report self-perceived declines in cognitive function but perform within normal limits on standardized tests. However, for some, these self-perceived changes may herald eventual decline to Alzheimer's disease (AD). In light of this, the relationship between SCD and APOE ɛ4, a known genetic risk factor for AD, has garnered interest; however, no systematic review of this literature exists. The current review (n = 36 articles) examined the prevalence of APOE ɛ4 in SCD samples relative to healthy and objectively impaired samples, and summarized APOE ɛ4-related risk of conversion from SCD to AD. Univariate ANOVA indicated that APOE ɛ4 frequency was comparable between healthy control and SCD samples, yet significantly higher in objectively impaired samples (i.e., MCI, AD) relative to either of these groups. Narrative review provided mixed evidence linking coincident APOE ɛ4-positive genotype and SCD to structural neuropathology. Though there was little evidence to suggest that APOE ɛ4 predisposes individuals to developing SCD, both APOE ɛ4 and SCD were found to confer individual and multiplicative risk of conversion to objective cognitive impairment. Combined, it is likely that a relationship between APOE ɛ4, SCD, and AD exists, though its exact nature remains undetermined. A clearer understanding of these relationships is hindered by a lack of standardization in SCD classification and a dearth of longitudinal outcome research. Wide-scale adoption of genetic screening for dementia risk in persons with SCD is considered premature at this time. Ethical considerations and clinical implications of genetic testing for dementia risk are discussed.

Relationships between Cognition and Activities of Daily Living in Alzheimer's Disease During a 5-Year Follow-Up: ALSOVA Study

BACKGROUND

Impaired cognition and activities of daily living (ADL) are core symptoms of Alzheimer's disease (AD), but their relationship is unclear.

OBJECTIVES

To explore relationships between cognitive domains and functional ability during 5-year follow-up in persons with AD.

METHODS

We analyzed ALSOVA study data from 236 individuals with very mild or mild AD at baseline. The CERAD Neuropsychological Battery (CERAD-NB) was used as a cognitive measure and Alzheimer's Disease Cooperative Study ADL (ADCS-ADL) as a functional measure, analyzing the IADL and BADL sub-scores separately. Annual regression models and linear mixed-effect models (LMMs) covering a 5-year follow-up period were used.

RESULTS

Annually, the CERAD-NB total and especially Verbal Fluency, Clock Drawing, and Constructional Praxis were associated with the total ADCS-ADL and IADL scores increasingly yet modestly, and to a lesser extent the BADL score. In the LMMs, the same measures and MMSE were associated with ADL.

CONCLUSION

Measures of executive function and visuoconstructive skills appear to be associated with caregiver-interview based ADL measure during the progression of AD.

Association Between Functional Performance and Alzheimer's Disease Biomarkers in Individuals Without Dementia

OBJECTIVES

To examine the cross-sectional association between functional performance and Alzheimer's disease (AD) neuroimaging biomarkers in individuals without dementia (cognitively unimpaired (CU), and those with mild cognitive impairment (MCI)).

DESIGN

Cross-sectional.

SETTING

Olmsted County, Minnesota.

PARTICIPANTS

Population-based Mayo Clinic Study of Aging (MCSA) participants (aged ≥ 50, mean age 71.3 ± 10.2; 53.4% male; 28.3% apolipoprotein (APO)E ε4 allele carriers, 1,578 CU, 204 MCI) who underwent ¹¹ C-Pittsburgh compound B (¹¹ C-PiB) positron emission tomography (PET) (N=1,782).

MEASUREMENTS

We defined an abnormal (high) ¹¹ C-PiB-PET retention ratio as a standardized uptake value ratio greater than 1.42 (high amyloid; A+), abnormal (reduced) AD signature cortical thickness (neurodegeneration; N+) as less than 2.67 mm (MRI measurement), and biomarker groups according to the combination of abnormality (or not) for amyloid accumulation (A+/A-) and neurodegeneration (N+/N-). Functional performance was assessed using the Clinical Dementia Rating (CDR) Sum of Boxes (SOB) for functional domains and the Functional Activities Questionnaire (FAQ).

RESULTS

Participants with a CDR-SOB (functional) score greater than 0 were almost 4 times as likely to have N + (odds ratio (OR)=3.92, 95% confidence interval (CI)=1.77-8.67, adjusting for age, sex, education, global cognitive z-score, and APOE ε4 allele status; p<.001) and those with a FAQ score greater than 0 were 1.5 times as likely to have A + (OR=1.48, 95% CI=1.04-2.11, p=.03). Higher FAQ scores were associated with greater odds of A+N + and A-N + in CU participants.

CONCLUSION

The findings of this cross-sectional study supplement limited available information that supports an association between functional performance and AD neuroimaging biomarkers very early in the dementia pathophysiology. The associations should be validated in longitudinal studies. J Am Geriatr Soc 66:2274-2281, 2018.

Cognitive and functional progression in Alzheimer disease: A prediction model of latent classes

OBJECTIVE

We sought to replicate a previously published prediction model for progression, developed in the Cache County Dementia Progression Study, using a clinical cohort from the National Alzheimer's Coordinating Center.

METHODS

We included 1120 incident Alzheimer disease (AD) cases with at least one assessment after diagnosis, originating from 31 AD centres from the United States. Trajectories of the Mini-Mental State Examination (MMSE) and Clinical Dementia Rating sum of boxes (CDR-sb) were modelled jointly over time using parallel-process growth mixture models in order to identify latent classes of trajectories. Bias-corrected multinomial logistic regression was used to identify baseline predictors of class membership and compare these with the predictors found in the Cache County Dementia Progression Study.

RESULTS

The best-fitting model contained 3 classes: Class 1 was the largest (63%) and showed the slowest progression on both MMSE and CDR-sb; classes 2 (22%) and 3 (15%) showed moderate and rapid worsening, respectively. Significant predictors of membership in classes 2 and 3, relative to class 1, were worse baseline MMSE and CDR-sb, higher education, and lack of hypertension. Combining all previously mentioned predictors yielded areas under the receiver operating characteristic curve of 0.70 and 0.75 for classes 2 and 3, respectively, relative to class 1.

CONCLUSIONS

Our replication study confirmed that it is possible to predict trajectories of progression in AD with relatively good accuracy. The class distribution was comparable with that of the original study, with most individuals being members of a class with stable or slow progression. This is important for informing newly diagnosed AD patients and their caregivers.

The Relationship between Behavioural Changes, Cognitive Symptoms, and Functional Disability in Primary Progressive Aphasia: A Longitudinal Study

BACKGROUND

The contribution of behavioural changes to functional decline is yet to be explored in primary progressive aphasia (PPA).

OBJECTIVES

(1) investigate functional changes in two PPA variants [semantic (svPPA) and non-fluent (nfvPPA)], at baseline and after 12 months; (2) investigate baseline differences in behavioural changes between groups, and (3) explore predictors of functional decline after a 12-month period.

METHODS

A longitudinal study involving 29 people with PPA (18 svPPA; 11 nfvPPA) seen annually in Sydney/Australia was conducted. A total of 114 functional and behavioural assessments were included for within-group (repeated-measures ANOVA; annual rate of change; multiple regression analyses) and between-group analyses (pairwise comparisons).

RESULTS

Functional profiles in svPPA and nfvPPA were similar in people with up to 5 years of disease duration. Behavioural changes were marked in svPPA patients (stereotypical behaviour and apathy) but did not predict annual rate of change of functional abilities; global cognitive scores at baseline did. Despite mild behavioural changes in nfvPPA (disinhibition, apathy), these were significant predictors of annual rate of functional change.

CONCLUSIONS

The presentation and interplay of behavioural changes and functional disability differ in svPPA and nfvPPA. These varying factors should be taken into account when considering prognosis, disease management, and selection of outcome measures for interventions.

Predicting cognitive function of the Malaysian elderly: a structural equation modelling approach

OBJECTIVES

The aim of this study was to identify the predictors of elderly's cognitive function based on biopsychosocial and cognitive reserve perspectives.

METHOD

The study included 2322 community-dwelling elderly in Malaysia, randomly selected through a multi-stage proportional cluster random sampling from Peninsular Malaysia. The elderly were surveyed on socio-demographic information, biomarkers, psychosocial status, disability, and cognitive function. A biopsychosocial model of cognitive function was developed to test variables' predictive power on cognitive function. Statistical analyses were performed using SPSS (version 15.0) in conjunction with Analysis of Moment Structures Graphics (AMOS 7.0).

RESULTS

The estimated theoretical model fitted the data well. Psychosocial stress and metabolic syndrome (MetS) negatively predicted cognitive function and psychosocial stress appeared as a main predictor. Socio-demographic characteristics, except gender, also had significant effects on cognitive function. However, disability failed to predict cognitive function.

CONCLUSION

Several factors together may predict cognitive function in the Malaysian elderly population, and the variance accounted for it is large enough to be considered substantial. Key factor associated with the elderly's cognitive function seems to be psychosocial well-being. Thus, psychosocial well-being should be included in the elderly assessment, apart from medical conditions, both in clinical and community setting.

Necroptosis activation in Alzheimer's disease

Alzheimer's disease (AD) is characterized by severe neuronal loss; however, the mechanisms by which neurons die remain elusive. Necroptosis, a programmed form of necrosis, is executed by the mixed lineage kinase domain-like (MLKL) protein, which is triggered by receptor-interactive protein kinases (RIPK) 1 and 3. We found that necroptosis was activated in postmortem human AD brains, positively correlated with Braak stage, and inversely correlated with brain weight and cognitive scores. In addition, we found that the set of genes regulated by RIPK1 overlapped significantly with multiple independent AD transcriptomic signatures, indicating that RIPK1 activity could explain a substantial portion of transcriptomic changes in AD. Furthermore, we observed that lowering necroptosis activation reduced cell loss in a mouse model of AD. We anticipate that our findings will spur a new area of research in the AD field focused on developing new therapeutic strategies aimed at blocking its activation.

Cerebrospinal Fluid Biomarkers and Reserve Variables as Predictors of Future "Non-Cognitive" Outcomes of Alzheimer's Disease

BACKGROUND

The influence of reserve variables and Alzheimer's disease (AD) biomarkers on cognitive test performance has been fairly well-characterized. However, less is known about the influence of these factors on "non-cognitive" outcomes, including functional abilities and mood.

OBJECTIVE

We examined whether cognitive and brain reserve variables mediate how AD biomarker levels in cognitively normal persons predict future changes in function, mood, and neuropsychiatric behavior.

METHODS

Non-cognitive outcomes were examined in 328 individuals 50 years and older enrolled in ongoing studies of aging and dementia at the Knight Alzheimer Disease Research Center (ADRC). All participants were cognitively normal at baseline (Clinical Dementia Rating [CDR] 0), completed cerebrospinal fluid (CSF) and structural neuroimaging studies within one year of baseline, and were followed for an average of 4.6 annual visits. Linear mixed effects models explored how cognitive reserve and brain reserve variables mediate the relationships between AD biomarker levels and changes in function, mood, and neuropsychiatric behavior in cognitively normal participants.

RESULTS

Education levels did not have a significant effect on predicting non-cognitive decline. However, participants with smaller brain volumes exhibited the worst outcomes on measures of mood, functional abilities, and behavioral disturbance. This effect was most pronounced in individuals who also had abnormal CSF biomarkers.

CONCLUSIONS

The findings suggest that brain reserve plays a stronger, or earlier, role than cognitive reserve in protecting against non-cognitive impairment in AD.

Describing the Sequence of Cognitive Decline in Alzheimer's Disease Patients: Results from an Observational Study

Background: Improved understanding of the pattern of cognitive decline in Alzheimer’s disease (AD) would be useful to assist primary care physicians in explaining AD progression to patients and caregivers.

Objective: To identify the sequence in which cognitive abilities decline in community-dwelling patients with AD.

Methods: Baseline data were analyzed from 1,495 patients diagnosed with probable AD and a Mini-Mental State Examination (MMSE) score ≤ 26 enrolled in the 18-month observational GERAS study. Proportional odds logistic regression models were applied to model MMSE subscores (orientation, registration, attention and concentration, recall, language, and drawing) and the corresponding subscores of the cognitive subscale of the Alzheimer’s Disease Assessment Scale (ADAS-cog), using MMSE total score as the index of disease progression. Probabilities of impairment start and full impairment were estimated at each MMSE total score level.

Results: From the estimated probabilities for each MMSE subscore as a function of the MMSE total score, the first aspect of cognition to start being impaired was recall, followed by orientation in time, attention and concentration, orientation in place, language, drawing, and registration. For full impairment in subscores, the sequence was recall, drawing, attention and concentration, orientation in time, orientation in place, registration, and language. The sequence of cognitive decline for the corresponding ADAS-cog subscores was remarkably consistent with this pattern.

Conclusion: The sequence of cognitive decline in AD can be visualized in an animation using probability estimates for key aspects of cognition. This might be useful for clinicians to set expectations on disease progression for patients and caregivers.

Association of AKAP6 and MIR2113 with cognitive performance in a population-based sample of older adults

Genetic factors make a substantial contribution to inter-individual variability in cognitive function. A recent meta-analysis of genome-wide association studies identified two loci, AKAP6 and MIR2113, that are associated with general cognitive function. Here, we extend this previous research by investigating the association of MIR2113 and AKAP6 with baseline and longitudinal non-linear change across a broad spectrum of cognitive domains in a community-based cohort of older adults without dementia. Two single nucleotide polymorphisms (SNPs), MIR211-rs10457441 and AKAP6-rs17522122 were genotyped in 1570 non-demented older Australians of European ancestry, who were examined up to 4 times over 12 years. Linear mixed effects models were used to examine the association between AKAP6 and MIR2113 with cognitive performance in episodic memory, working memory, vocabulary, perceptual speed and reaction time at baseline and with linear and quadratic rates of change. AKAP6-rs17522122*T was associated with worse baseline performance in episodic memory, working memory, vocabulary and perceptual speed, but it was not associated with cognitive change in any domain. MIR2113-rs10457441*T was associated with accelerated decline in episodic memory. No other associations with baseline cognitive performance or with linear or quadratic rate or cognitive changes were observed for this SNP. These results confirm the previous finding that AKAP6 is associated with performance across multiple cognitive domains at baseline but not with cognitive decline, while MIR2113 primarily affects the rate at which memory declines over time.

Modeling Alzheimer Disease Through Functional Independence and Participation

INTRODUCTION

The relationship between cognitive and functional impairment in Alzheimer Disease (AD) at the earliest stages of the disease is not well characterized. This study aimed at investigating such relationships along AD evolution by means of the Disability Assessment for Dementia (DAD).

METHODS

Consecutive pairs of AD outpatients and their primary informal caregivers were enrolled. Patients were evaluated by means of the Mini Mental State Examination and neuropsychological tests. A clinician completed the Clinical Dementia Rating Scale to stage dementia severity and interviewed the caregivers to complete the Neuropsychiatric Inventory to assess behavioral disturbances and the DAD to evaluate patients' functional competence.

RESULTS

A total of 158 dyads were enrolled; the Mini Mental State Examination score was used to stratify patients into 4 groups (>24; 20 to 23.9; 10 to 19.9; <10) that were compared. The statistical analysis revealed that all the cognitive domains were positively related to functional independence, but only logical and executive functions seemed to predict autonomy. An intergroup comparison did not show significant differences in the DAD subscales measuring initiation, planning and organization, and performance. The role of education emerged, confirming the relevance of cognitive reserve.

DISCUSSION

As the field moves toward earlier intervention in preclinical AD, the detection of early functional changes may drive the definition of trials on prevention or intervention for dementia.

Drug development in Alzheimer's disease: the path to 2025

The global impact of Alzheimer's disease (AD) continues to increase, and focused efforts are needed to address this immense public health challenge. National leaders have set a goal to prevent or effectively treat AD by 2025. In this paper, we discuss the path to 2025, and what is feasible in this time frame given the realities and challenges of AD drug development, with a focus on disease-modifying therapies (DMTs). Under the current conditions, only drugs currently in late Phase 1 or later will have a chance of being approved by 2025. If pipeline attrition rates remain high, only a few compounds at best will meet this time frame. There is an opportunity to reduce the time and risk of AD drug development through an improvement in trial design; better trial infrastructure; disease registries of well-characterized participant cohorts to help with more rapid enrollment of appropriate study populations; validated biomarkers to better detect disease, determine risk and monitor disease progression as well as predict disease response; more sensitive clinical assessment tools; and faster regulatory review. To implement change requires efforts to build awareness, educate and foster engagement; increase funding for both basic and clinical research; reduce fragmented environments and systems; increase learning from successes and failures; promote data standardization and increase wider data sharing; understand AD at the basic biology level; and rapidly translate new knowledge into clinical development. Improved mechanistic understanding of disease onset and progression is central to more efficient AD drug development and will lead to improved therapeutic approaches and targets. The opportunity for more than a few new therapies by 2025 is small. Accelerating research and clinical development efforts and bringing DMTs to market sooner would have a significant impact on the future societal burden of AD. As these steps are put in place and plans come to fruition, e.g., approval of a DMT, it can be predicted that momentum will build, the process will be self-sustaining, and the path to 2025, and beyond, becomes clearer.

Cognitive Impairment Precedes and Predicts Functional Impairment in Mild Alzheimer's Disease

Background: The temporal relationship of cognitive deficit and functional impairment in Alzheimer’s disease (AD) is not well characterized. Recent analyses suggest cognitive decline predicts subsequent functional decline throughout AD progression.

Objective: To better understand the relationship between cognitive and functional decline in mild AD using autoregressive cross-lagged (ARCL) panel analyses in several clinical trials.

Methods: Data included placebo patients with mild AD pooled from two multicenter, double-blind, Phase 3 solanezumab (EXPEDITION/2) or semagacestat (IDENTITY/2) studies, and from AD patients participating in the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Cognitive and functional outcomes were assessed using AD Assessment Scale-Cognitive subscale (ADAS-Cog), AD Cooperative Study-Activities of Daily Living instrumental subscale (ADCS-iADL), or Functional Activities Questionnaire (FAQ), respectively. ARCL panel analyses evaluated relationships between cognitive and functional impairment over time.

Results: In EXPEDITION, ARCL panel analyses demonstrated cognitive scores significantly predicted future functional impairment at 5 of 6 time points, while functional scores predicted subsequent cognitive scores in only 1 of 6 time points. Data from IDENTITY and ADNI programs yielded consistent results whereby cognition predicted subsequent function, but not vice-versa.

Conclusions: Analyses from three databases indicated cognitive decline precedes and predicts subsequent functional decline in mild AD dementia, consistent with previously proposed hypotheses, and corroborate recent publications using similar methodologies. Cognitive impairment may be used as a predictor of future functional impairment in mild AD dementia and can be considered a critical target for prevention strategies to limit future functional decline in the dementia process.

Function and clinical meaningfulness of treatments for mild Alzheimer's disease

Introduction

Effectiveness of Alzheimer's disease (AD) treatments is commonly evaluated with coprimary outcomes; cognition with function to ensure clinical meaningfulness of a cognitive effect.

Methods

We reviewed the literature for functional outcomes in mild AD or mild cognitive impairment (MCI) patients (distinct from combined mild-moderate/severe AD) treated with approved AD drugs. Cognitive and functional treatment differences in mild AD patients in solanezumab EXPEDITION/EXPEDITION2 studies were compared across time.

Results

Seven publications provided MCI/mild AD functional outcomes, one of which reported a significant functional treatment effect. Secondary analyses of EXPEDITION studies suggested a smaller functional effect of solanezumab relative to cognition. An increasing effect of solanezumab over 18 months was shown for cognition and function.

Discussion

Function as the sole measure to demonstrate clinical meaningfulness of cognitive effects in mild AD may have limitations. For disease-modifying treatments, point differences on cognitive and functional scales should be qualified with duration of treatment.

Effects of different types of physical activity on the cognitive functions and attention in older people: A randomized controlled study

This study aimed to evaluate the effects of different types of exercise on cognition. Eighty participants, 32 males and 48 females, aged 66.96 ± 11.73, volunteered for this study. The participants were randomly divided into the four following groups: Resistance Group (RG; n=20), involved in high intensity strength training; Cardiovascular Group (CVG; n=20), involved in high intensity cardiovascular training; Postural Group (PG; n=20) involved in low intensity training, based on postural and balance exercises; and Control Group (CG; n=20). Exercises were performed over the course of 12 weeks. All participants were tested for their cognitive functions pre- and post-intervention using the following neurocognitive tests: the Attentive Matrices Test, Raven's Progressive Matrices, Stroop Color and Word Interference Test, Trail Making Test and Drawing Copy Test. Statistical analysis showed that the CVG group improved significantly in the Attentive Matrices Test and Raven's Progressive Matrices (both p=<0.05), whereas the RG group improved in Drawing Copy Test time (p=<0.05). These results confirm that different types of exercise interventions have unique effects on cognition. Cardiovascular training is effective in improving performance attentive and analytic tasks, whereas resistance training is effective in improving praxis. Further investigation is necessary to evaluate the combination of the two exercise types in order to ascertain if their respective effects can be summated when performed together.