Cognitive Trajectories in Community-Dwelling Older Adults and Incident Dementia, Disability and Death: A 10-Year Longitudinal Study

A Novel Cognitive Frailty Index for Geriatric Mice

Loss of cognitive function is a significant challenge in aging, and developing models to understand and target cognitive decline is crucial for the development of Geroscience-based interventions. Aged mice offer a valuable model as they share features of cognitive decline with humans. Despite numerous studies, knowledge of longitudinal age-related cognitive changes and cognitive frailty in naturally aging mice is limited, particularly in cohorts exceeding 30 months of age, where cognitive decline is more pronounced. Moreover, the impaired physical function of aged mice is known to affect latency-based strategies to measure cognitive performances. Here, we show a comprehensive longitudinal assessment using the Barnes Maze test in a large cohort of 424 aged (≥ 21 months) C57BL/6J mice. We introduced a new metric, the Cognitive Frailty Index (CoFI), which summarizes different age-associated Barnes Maze parameters into a unique function. CoFI strongly associates with advancing age and mortality, offering a reliable ability to discriminate long- and short-lived mice. We also established a CoFI cut-off and a physically adjusted CoFI, both of which can distinguish between physical and cognitive frailty. This is further supported by the enhanced predictive power when physical and cognitive frailty are combined to assess short-term mortality. Moreover, the computation method for CoFI is adaptable to various cognitive assessment tests, leveraging procedures akin to those used for calculating other frailty indices. In conclusion, through robust longitudinal tracking, CoFI has the potential to become an important ally in assessing the effectiveness of Geroscience-based interventions to counteract age-related cognitive impairment.

ATTRV30M amyloidosis post-liver transplant: cognition and long-term survival

BACKGROUND

Patients with hereditary amyloidosis related to transthyretin (ATTRv amyloidosis) treated with liver transplant (LTx) often have central nervous system (CNS) manifestations, including cognitive dysfunction. The aim of this study was to explore the long-term outcome associated with neuropsychological test performance.

METHODS

A retrospective longitudinal review was conducted in a cohort of 289 ATTRv amyloidosis patients with the Val30Met mutation (ATTRV30M amyloidosis) who underwent a neuropsychological assessment (T1) 1-23 years (median = 11) post-LTx and 20-189 months (median = 81) prior to the study review. Clinical records were reviewed. The Kaplan-Meier and Cox regression methods were used to estimate survival and adjusted hazard ratios for all-cause mortality.

RESULTS

Impaired performance on Dementia Rating Scale-2, Semantic Fluency, Phonemic Fluency and Trail Making Test Part B were predictive of shorter survival after neuropsychological assessment, even when demographic and clinical variables (i.e. education, age at disease onset ≥ 50, disease duration at LTx, interval between LTx and T1, age at T1, Modified Polyneuropathy Disability score at T1, and history of focal neurological episodes at T1) were taken into account. Measures of verbal learning and memory were not predictive of mortality.

CONCLUSIONS

Study results demonstrate that cognitive impairment in ATTRV30M amyloidosis patients treated with LTx predicts long-term survival.

Trajectories of Cognitive Change and Their Association with All-Cause Mortality Among Chinese Older Adults: Results from the Chinese Longitudinal Healthy Longevity Survey

The analysis of cognitive trajectories is relatively underexplored in China. Furthermore, most previous studies examining the association between cognitive function and mortality have been limited to cross-sectional perspectives. This study aims to identify distinct cognitive trajectories and the corresponding influencing factors and investigate the impact of these trajectories on all-cause mortality in Chinese older adults. A total of 6232 subjects aged 65 years and above were drawn from the Chinese Longitudinal Healthy Longevity Survey. Growth mixture models were utilized to identify different cognitive trajectories, while Cox proportional hazards models were used to examine the association between the cognitive trajectories and all-cause mortality after adjusting for covariates. Four cognitive trajectories were identified: rapid decline group, slow decline group, low-level stable group, and high-level stable group. Some factors such as age, sex, and marital status were significantly associated with trajectories. Compared to the high-level stable group, adjusted hazard ratios and 95% confidence intervals (CIs) for the all-cause mortality were 3.87 (95% CI: 3.35-4.48), 1.41 (95% CI: 1.24-1.59), and 1.37 (95% CI: 1.18-1.58) for the rapid decline group, the slow decline group, and the low-level stable group, respectively, indicating that these three groups had a higher mortality risk. In summary, these findings facilitate the development of targeted health promotion measures, which have implications for reducing the social and economic burdens of cognitive decline.

Depressive symptoms and cognitive decline in older adults

OBJECTIVES

Few studies have examined the impact of late-life depression trajectories on specific domains of cognitive function. This study aims to delineate how different depressive symptom trajectories specifically affect cognitive function in older adults.

DESIGN

Prospective longitudinal cohort study.

SETTING

Australia and the United States of America.

PARTICIPANTS

In total, 11,035 community-dwelling older adults with a mean age of 75 years.

MEASUREMENTS

Depressive trajectories were modelled from depressive symptoms according to annual Centre for Epidemiological Studies Depression Scale 10 (CES-D-10) surveys. Four trajectories of depressive symptoms were identified: low ("nondepressed"), consistently mild ("subthreshold depression"), consistently moderate ("persistent depression"), and initially low but increasing ("emerging depression"). Global cognition (Modified Mini-Mental State Examination [3MS]), verbal fluency (Controlled Oral Word Association Test [COWAT]), processing speed (Symbol Digit Modalities Test [SDMT]), episodic memory (Hopkins Verbal Learning Test - Revised [HVLT-R]), and a composite z-score were assessed over a subsequent median 2 years.

RESULTS

Subthreshold depression predicted impaired performance on the SDMT (Cohen's d -0.04) and composite score (-0.03); emerging depression predicted impaired performance on the SDMT (-0.13), HVLT-R (-0.09), 3 MS (-0.08) and composite score (-0.09); and persistent depression predicted impaired performance on the SDMT (-0.08), 3 MS (-0.11), and composite score (-0.09).

CONCLUSIONS

Depressive symptoms are associated with later impaired processing speed. These effects are small. Diverse depression trajectories have different impacts on cognitive function.

Association Between Cognitive Trajectories and Subsequent Health Status, Depressive Symptoms, and Mortality Among Older Adults in the United States: Findings From a Nationally Representative Study

BACKGROUND

Cognitive decline may be an early indicator of major health issues in older adults, though research using population-based data is lacking. Researchers objective was to assess the relationships between distinct cognitive trajectories and subsequent health outcomes, including health status, depressive symptoms, and mortality, using a nationally representative cohort.

METHODS

Data were drawn from the National Health and Aging Trends Study. Global cognition was assessed annually between 2011 and 2018. The health status of 4 413 people, depressive symptoms in 4 342 individuals, and deaths among 5 955 living respondents were measured in 2019. Distinct cognitive trajectory groups were identified using an innovative Bayesian group-based trajectory model. Ordinal logistic, Poisson, and logistic regression models were used to examine the associations between cognitive trajectories and subsequent health outcomes.

RESULTS

Researchers identified five cognitive trajectory groups with distinct baseline values and subsequent changes in cognitive function. Compared with the group with stably high cognitive function, worse cognitive trajectories (ie, lower baseline values and sharper declines) were associated with higher risks of poor health status, depressive symptoms, and mortality, even after adjusting for relevant covariates.

CONCLUSIONS

Among older adults, worse cognitive trajectories are strongly associated with subsequent poor health status, high depressive symptoms, and high mortality risks. Regular screening of cognitive function may help to facilitate early identification and interventions for older adults susceptible to adverse health outcomes.

Longitudinal trajectories of cognitive aging

PURPOSE OF REVIEW

This review summarizes recent evidence related to the cognitive trajectories of aging, the factors associated with the different trajectories, and the effect of sex on cognitive decline.

RECENT FINDINGS

Trajectories of cognitive aging identified in different studies vary in number, in the proportion of individuals falling into each of the classes and in the predictors of class membership. Trajectories observed include types with 'rapid decline', those with 'gradual decline' and those with 'maintenance of high level' of cognitive performance. Predictors of decline and predictors of maintenance of cognitive performance may be different. While factors such as education were in general associated with high performance, and reversely with low performance, other factors, such as depression were predictors only for some groups, particularly the declining ones. Sex differences in cognitive trajectories and the associated predictive factors have also been identified.

SUMMARY

The findings on education may be particularly important in populations with low educational level, especially among women and the findings on depression have special interest in preventing cognitive decline in women. Further work is required to explain intriguing inconsistencies observed in the literature.

Association of social integration with cognitive function trajectories among Chinese older adults: evidence from the China health and retirement longitudinal study (CHARLS)

Background

The prevalence of cognitive impairment among older adults remains high. It has been proven that social integration is related to cognitive function. However, limited research has examined the association of social integration and its different dimensions with cognitive function trajectories of older adults.

Methods

The data were from the China Health and Retirement Longitudinal Study (CHARLS) spanning 2013 (T1) to 2018 (T3). A total of 3,977 older adults were included in the final analysis. Cognitive function was measured with items from an adapted Chinese version of the Mini-Mini-Mental Mental State Examination (MMSE), while the measurement of social integration included three dimensions: economic integration, relational integration and community integration. A group-based trajectory model (GBTM) was used to identify cognitive trajectory groups among participants and an unordered multinomial logistic regression was employed to explore the association of baseline social integration and its three dimensions with cognitive function trajectories.

Result

Three cognitive function trajectory groups were identified: low-decline group (24.1%), medium-decline group (44.2%) and high-stable group (31.7%). Comparing to the medium-decline trajectory group, older adults with higher social integration scores were more likely to be in the high-stable trajectory group (OR = 1.087, 95%CI: 1.007 ~ 1.174), while less likely to be in the low-decline group (OR = 0.806, 95%CI: 0.736 ~ 0.882). Among the different dimensions of social integration, older adults with higher community integration scores were more likely to be in the high-stable trajectory group (OR = 1.222, 95%CI: 1.026 ~ 1.456); Older adults with higher relational integration scores were less likely to be in the low-decline trajectory group (OR = 0.816, 95%CI: 0.734 ~ 0.906). The economic integration was not found to correlate with the cognitive function trajectories. Stratified analyses revealed that the association between community integration and cognitive trajectories was only significant among older adults aged 60 to 69, and the association between relational integration and cognitive trajectories was only significant among older adults who was agricultural household registration.

Conclusion

The developmental trajectories of cognitive function among Chinese older adults are heterogeneous. Social integration is significantly related to the trajectories of cognitive function in Chinese older adults. Measures should be taken to promote social integration of Chinese older adults to reduce the decline of cognitive function.

Harnessing cognitive trajectory clusterings to examine subclinical decline risk factors

Cognitive decline in Alzheimer's disease and other dementias typically begins long before clinical impairment. Identifying people experiencing subclinical decline may facilitate earlier intervention. This study developed cognitive trajectory clusters using longitudinally based random slope and change point parameter estimates from a Preclinical Alzheimer's disease Cognitive Composite and examined how baseline and most recently available clinical/health-related characteristics, cognitive statuses and biomarkers for Alzheimer's disease and vascular disease varied across these cognitive clusters. Data were drawn from the Wisconsin Registry for Alzheimer's Prevention, a longitudinal cohort study of adults from late midlife, enriched for a parental history of Alzheimer's disease and without dementia at baseline. Participants who were cognitively unimpaired at the baseline visit with ≥3 cognitive visits were included in trajectory modelling (n = 1068). The following biomarker data were available for subsets: positron emission tomography amyloid (amyloid: n = 367; [11C]Pittsburgh compound B (PiB): global PiB distribution volume ratio); positron emission tomography tau (tau: n = 321; [18F]MK-6240: primary regions of interest meta-temporal composite); MRI neurodegeneration (neurodegeneration: n = 581; hippocampal volume and global brain atrophy); T2 fluid-attenuated inversion recovery MRI white matter ischaemic lesion volumes (vascular: white matter hyperintensities; n = 419); and plasma pTau217 (n = 165). Posterior median estimate person-level change points, slopes' pre- and post-change point and estimated outcome (intercepts) at change point for cognitive composite were extracted from Bayesian Bent-Line Regression modelling and used to characterize cognitive trajectory groups (K-means clustering). A common method was used to identify amyloid/tau/neurodegeneration/vascular biomarker thresholds. We compared demographics, last visit cognitive status, health-related factors and amyloid/tau/neurodegeneration/vascular biomarkers across the cognitive groups using ANOVA, Kruskal-Wallis, χ2, and Fisher's exact tests. Mean (standard deviation) baseline and last cognitive assessment ages were 58.4 (6.4) and 66.6 (6.6) years, respectively. Cluster analysis identified three cognitive trajectory groups representing steep, n = 77 (7.2%); intermediate, n = 446 (41.8%); and minimal, n = 545 (51.0%) cognitive decline. The steep decline group was older, had more females, APOE e4 carriers and mild cognitive impairment/dementia at last visit; it also showed worse self-reported general health-related and vascular risk factors and higher amyloid, tau, neurodegeneration and white matter hyperintensity positive proportions at last visit. Subtle cognitive decline was consistently evident in the steep decline group and was associated with generally worse health. In addition, cognitive trajectory groups differed on aetiology-informative biomarkers and risk factors, suggesting an intimate link between preclinical cognitive patterns and amyloid/tau/neurodegeneration/vascular biomarker differences in late middle-aged adults. The result explains some of the heterogeneity in cognitive performance within cognitively unimpaired late middle-aged adults.