Associations Between Declining Physical and Cognitive Functions in the Lothian Birth Cohort 1936

Longitudinal relationship between grip strength and cognitive function in a European population older than 50 years: A cross-lagged panel model

OBJECTIVES

The aim of this study was to investigate the dynamic longitudinal relationship between grip strength and cognitive function.

METHODS

6175 participants aged ≥50 years were included in the study using three waves of follow-up data from the Survey of Health, Ageing, and Retirement in Europe in 2015 (T1), 2017 (T2) and 2019 (T3). Cognitive function was assessed using numeracy, verbal fluency, immediate recall, delayed recall and total. The cross-lagged panel model was used for analysis.

RESULTS

There was a correlation between grip strength and cognitive function. Standardized path coefficient from numeracy T1 to grip strength T2 was 0.017 (p = 0.003), and from numeracy T2 to grip strength T3 was 0.014 (p = 0.012). Standardized path coefficient from grip strength T1 to numeracy T2 was 0.096 (p < 0.001), and from grip strength T2 to numeracy T3 was 0.113 (p < 0.001). Other indicators of cognitive function had similar relationships with grip strength.

CONCLUSIONS

The study found a statistically significant longitudinal and bidirectional relationship between grip strength and cognitive function in a sample of people aged ≥50 years from several European countries.

Identifying and predicting physical limitation and cognitive decline trajectory group of older adults in China: A data-driven machine learning analysis

OBJECTIVE

This study aimed to utilize data-driven machine learning methods to identify and predict potential physical and cognitive function trajectory groups of older adults and determine their crucial factors for promoting active ageing in China.

METHODS

Longitudinal data on 3026 older adults from the Chinese Longitudinal Healthy Longevity and Happy Family Survey was used to identify potential physical and cognitive function trajectory groups using a group-based multi-trajectory model (GBMTM). Predictors were selected from sociodemographic characteristics, lifestyle factors, and physical and mental conditions. The trajectory groups were predicted using data-driven machine learning models and dynamic nomogram. Model performance was evaluated by area under the receiver operating characteristics curve (AUROC), area under the precision-recall curve (PRAUC), and confusion matrix.

RESULTS

Two physical and cognitive function trajectory groups were determined, including a trajectory group with physical limitation and cognitive decline (14.18 %) and a normal trajectory group (85.82 %). Logistic regression performed well in predicting trajectory groups (AUROC = 0.881, PRAUC = 0.649). Older adults with lower baseline score of activities of daily living, older age, less frequent housework, and fewer actual teeth were more likely to experience physical limitation and cognitive decline trajectory group.

LIMITATION

This study didn't carry out external validation.

CONCLUSIONS

This study shows that GBMTM and machine learning models effectively identify and predict physical limitation and cognitive decline trajectory group. The identified predictors might be essential for developing targeted interventions to promote healthy ageing.

Predictors of cognitive and physical decline: Results from the Health Aging and Body Composition Study

Background

Risk factors for cognitive decline and physical decline have been studied independently, however older adults might experience decline in both areas i.e., dual decline. Risk factors associated with dual decline are largely unknown and have significant implications on health outcomes. The aim of this study is to explore risk factors associated with dual decline.

Methods

Using data from the Health, Aging and Body Composition (Health ABC) study, a longitudinal prospective cohort study, we examined trajectories of decline based on repeated measures of the Modified Mini-Mental State Exam (3MSE) and the Short Physical Performance Battery (SPPB) across 6 years (n=1,552). We calculated four mutually exclusive trajectories of decline and explored predictors of decline: cognitive decline (n = 306) = lowest quartile of slope on the 3MSE or 1.5 SD below mean at baseline, physical decline (n = 231) = lowest quartile of slope on the SPPB or 1.5 SD below mean at baseline, dual decline (n = 110) = lowest quartile in both measures or 1.5 SD below mean in both measures at baseline. Individuals who did not meet criteria for one of the decline groups were classified as the reference group. (n= 905).

Results

Multinomial logistic regression tested the association of 17 baseline risk factors with decline. Odds of dual decline where significantly higher for individuals at baseline with depressive symptoms (CES-D >16) (Odds Ratio (OR)=2.49, 95% Confidence Interval (CI): 1.05-6.29), ApoE-ε4 carrier (OR= 2.09, 95% CI: 1.06-1.95), or if individuals had lost 5+lbs in past year (OR=1.79, 95% CI: 1.13-2.84). Odds were significantly lower for individuals with a higher score on the Digit Symbol Substitution Test per standard deviation (OR per SD: 0.47, 95% CI 0.36-0.62) and faster 400-meter gait (OR per SD= 0.49, 95% CI: 0.37-0.64).

Conclusion

Among predictors, depressive symptoms at baseline significantly increased the odds of developing dual decline but was not associated with decline in the exclusively cognitive or physical decline groups. APOE-ε4 status increased the odds for cognitive decline and dual decline but not physical decline. More research on dual decline is needed because this group represents a high risk, vulnerable subset of older adults.

A 13-Year Time-Lagged Description of General Cognitive and Functional Abilities in Older Men: A Cross-Lagged Panel Model

Objectives: The purpose of this study was to evaluate a cross-lagged panel model of general cognition and functional abilities over 13 years. The goal was to determine whether general cognitive abilities predict or precede functional decline versus functional abilities predicting cognitive decline. Methods: The sample included 3508 men (71-93 years of age at baseline) of the Kuakini Honolulu-Asia Aging Study who were tested repeatedly using a global cognitive test and an assessment of functional capacity. Education and age served as covariates. Cross-lagged models were tested, assessing stationarity of stability and cross-lags. Results: The overall model fit the data well. Cognitive scores had better stability than functional abilities and predicted functional abilities more strongly than functional abilities predicted cognitive scores over time. The strength of all cross-lags increased over time. Discussion: These longitudinal data show that cognitive scores predicted functional decline in a population-based study of older men.

Asymmetrical Handgrip Strength Is Associated with Lower Cognitive Performance in the Elderly

(1) Background: Several studies have reported that handgrip strength (HGS) may be a sign of lower cognitive performance. However, studies supporting an association between asymmetrical HGS and cognitive function are lacking. This study aimed to determine the association between asymmetrical HGS and cognitive performance among the elderly. (2) Methods: The study sample included 2729 individuals aged ≥60 years-old who participated in the 2011-2014 National Health and Nutrition Examination Survey. The cognitive tests consisted of the word learning and recall modules from the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Animal Fluency Test, and Digit Symbol Substitution Test (DSST). HGS was measured using a handgrip dynamometer, and asymmetrical HGS was used to calculate HGS. (3) Results: Of the 2729 participants, 53.0% were aged 60 to 69 years-old, and 47.0% were aged 70 years and older. All cognitive performance scores were significantly correlated with asymmetrical HGS in both age groups. After adjusting for confounders, there was a significant association between DSST and HGS asymmetry in both age groups. Contrastingly, a significant association was only observed for the relationship between the CERAD test and HGS asymmetry in the ≥70 year-old group. (4) Conclusions: We found that low cognitive function was associated with asymmetrical HGS in elderly participants in the United States. Thus, asymmetrical HGS may be an important predictor of cognitive deficits. However, further research is required to confirm our results and to establish possible mechanisms.

Effects of exergame and video game training on cognitive and physical function in older adults: A randomized controlled trial

Few studies have simultaneously explored the training effects of exergame and video game. The purpose of this study was to investigate the effects of exergame and video game training on cognitive and physical function in healthy older adults. Eighty-four healthy older adults were randomly assigned to exergame training group, video game training group, and control group. Cognitive and physical function was measured before and after the training. Both training groups improved in verbal memory and aerobic endurance, but the training effects were greater in the exergame training group. The exergame training group also showed significant improvement in lower limb strength and balance. The current study provides evidence that exergame training, incorporating both cognitive engagement and physical activity, exerts greater benefits than cognitively engaging video game training alone. The findings shed lights into the future use of exergame in preventing cognitive and physical function decline in older adults.

Associations of Word Memory, Verbal Fluency, Processing Speed, and Crystallized Cognitive Ability With One-Legged Balance Performance in Mid- and Later Life

BACKGROUND

Cognitive integration of sensory input and motor output plays an important role in balance. Despite this, it is not clear if specific cognitive processes are associated with balance and how these associations change with age. We examined longitudinal associations of word memory, verbal fluency, search speed, and reading ability with repeated measures of one-legged balance performance.

METHOD

Up to 2 934 participants in the MRC National Survey of Health and Development, a British birth cohort study, were included. At age 53, word memory, verbal fluency, search speed, and reading ability were assessed. One-legged balance times (eyes closed) were measured at ages 53, 60-64, and 69 years. Associations between each cognitive measure and balance time were assessed using random-effects models. Adjustments were made for sex, death, attrition, height, body mass index, health conditions, health behaviors, education, and occupational class.

RESULTS

In sex-adjusted models, 1 SD higher scores in word memory, search speed, and verbal fluency were associated with 14.1% (95% CI: 11.3, 16.8), 7.2% (4.4, 9.9), and 10.3% (7.5, 13.0) better balance times at age 53, respectively. Higher reading scores were associated with better balance, although this association plateaued. Associations were partially attenuated in mutually adjusted models and effect sizes were smaller at ages 60-64 and 69. In fully adjusted models, associations were largely explained by education, although remained for word memory and search speed.

CONCLUSIONS

Higher cognitive performance across all measures was independently associated with better balance performance in midlife. Identification of individual cognitive mechanisms involved in balance could lead to opportunities for targeted interventions in midlife.

Aging-related Alzheimer's disease-like neuropathology and functional decline in captive vervet monkeys (Chlorocebus aethiops sabaeus)

Age-related neurodegeneration characteristic of late-onset Alzheimer's disease (LOAD) begins in middle age, well before symptoms. Translational models to identify modifiable risk factors are needed to understand etiology and identify therapeutic targets. Here, we outline the evidence supporting the vervet monkey (Chlorocebus aethiops sabaeus) as a model of aging-related AD-like neuropathology and associated phenotypes including cognitive function, physical function, glucose handling, intestinal physiology, and CSF, blood, and neuroimaging biomarkers. This review provides the most comprehensive multisystem description of aging in vervets to date. This review synthesizes a large body of evidence that suggests that aging vervets exhibit a coordinated suite of traits consistent with early AD and provide a powerful, naturally occurring model for LOAD. Notably, relationships are identified between AD-like neuropathology and modifiable risk factors. Gaps in knowledge and key limitations are provided to shape future studies to illuminate mechanisms underlying divergent neurocognitive aging trajectories and to develop interventions that increase resilience to aging-associated chronic disease, particularly, LOAD.

Grip strength from midlife as an indicator of later-life brain health and cognition: evidence from a British birth cohort

BACKGROUND

Grip strength is an indicator of physical function with potential predictive value for health in ageing populations. We assessed whether trends in grip strength from midlife predicted later-life brain health and cognition.

METHODS

446 participants in an ongoing British birth cohort study, the National Survey of Health and Development (NSHD), had their maximum grip strength measured at ages 53, 60-64, and 69, and subsequently underwent neuroimaging as part of a neuroscience sub-study, referred to as "Insight 46", at age 69-71. A group-based trajectory model identified latent groups of individuals in the whole NSHD cohort with below- or above-average grip strength over time, plus a reference group. Group assignment, plus standardised grip strength levels and change from midlife were each related to measures of whole-brain volume (WBV) and white matter hyperintensity volume (WMHV), plus several cognitive tests. Models were adjusted for sex, body size, head size (where appropriate), sociodemographics, and behavioural and vascular risk factors.

RESULTS

Lower grip strength from midlife was associated with smaller WBV and lower matrix reasoning scores at age 69-71, with findings consistent between analysis of individual time points and analysis of trajectory groups. There was little evidence of an association between grip strength and other cognitive test scores. Although greater declines in grip strength showed a weak association with higher WMHV at age 69-71, trends in the opposite direction were seen at individual time points with higher grip strength at ages 60-64, and 69 associated with higher WMHV.

CONCLUSIONS

This study provides preliminary evidence that maximum grip strength may have value in predicting brain health. Future work should assess to what extent age-related declines in grip strength from midlife reflect concurrent changes in brain structure.

Early manifestation of gait alterations in the Tg2576 mouse model of Alzheimer's disease

There is strong clinical evidence that multifaceted gait abnormalities may be manifested at early stages of Alzheimer's disease (AD), are related to cognitive decline, and can be used as an early biomarker to identify patients at risk of progressing to full-blown dementia. Despite their importance, gait abnormalities have not been investigated in mouse models of AD, which replicate important aspects of the human disease. The Tg2576 is frequently used in AD research to test therapeutic interventions targeting cellular mechanisms contributing to the genesis of AD. This transgenic mouse strain overexpresses a mutant form of the 695 amino acid isoform of human amyloid precursor protein with K670N and M671L mutations (APPK670/671L) linked to early-onset familial AD. Tg2576 mice exhibit impaired cognitive functions and increased cortical and hippocampal soluble β-amyloid levels starting from 5 months of age and increased insoluble β-amyloid levels and amyloid plaques that resemble senile plaques associated with human AD by 13 months of age. To demonstrate early manifestations of gait dysfunction in this relevant preclinical model, we characterized gait and motor performance in 10-month-old Tg2576 mice and age-matched littermate controls using the semi-automated, highly sensitive, Catwalk XT system. We found that Tg2576 mice at the pre-plaque stage exhibited significantly altered duty cycle and step patterns and decreased stride length and stride time. Base-of-support, stride time variability, stride length variability, cadence, phase dispersions and gait symmetry indices were unaltered. The presence of measurable early gait abnormalities during the pre-plaque stages of AD in this relevant preclinical mouse model has direct translational relevance and supports the view that longitudinal monitoring of gait performance could be used in addition to behavioral testing to evaluate progression of the disease and to assess treatment efficacy.

Impact of COVID-19 lockdown on psychosocial factors, health, and lifestyle in Scottish octogenarians: The Lothian Birth Cohort 1936 study

Background

Little is known about effects of COVID-19 lockdown on psychosocial factors, health and lifestyle in older adults, particularly those aged over 80 years, despite the risks posed by COVID-19 to this age group.

Methods

Lothian Birth Cohort 1936 members, residing mostly in Edinburgh and the surrounding Lothians regions in Scotland, mean age 84 years (SD = 0.3), responded to an online questionnaire in May 2020 (n = 190). We examined responses (experience and knowledge of COVID-19; adherence to guidance; impact on day-to-day living; social contact; self-reported physical and mental health; loneliness; and lifestyle) and relationships between previously-measured characteristics and questionnaire outcomes.

Results

Four respondents experienced COVID-19; most had good COVID-19 knowledge (94.7%) and found guidance easy to understand (86.3%). There were modest declines in self-reported physical and mental health, and 48.2% did less physical activity. In multivariable regression models, adherence to guidance by leaving the house less often associated with less professional occupational class (OR = 0.71, 95%CI 0.51–0.98) and poorer self-rated general health (OR = 0.62, 95%CI 0.42–0.92). Increased internet use associated with female sex (OR = 2.32, 95%CI 1.12–4.86) and higher general cognitive ability (OR = 1.53, 95%CI 1.03–2.33). Loneliness associated with living alone (OR = 0.15, 95%CI 0.07–0.31) and greater anxiety symptoms (OR = 1.76, 95%CI 0.45–1.24). COVID-19 related stress associated with lower emotional stability scores (OR = 0.40, 95%CI 0.24–0.62). Decreased physical activity associated with less professional occupational class (OR = 1.43, 95%CI 1.04–1.96), and lower general cognitive ability (OR = 0.679, 95%CI 0.491–0.931).

Conclusions

Characteristics including cognitive function, occupational class, self-rated health, anxiety, and emotional stability, may be related to risk of poorer lockdown-related psychosocial and physical outcomes.

Temporal emergence of age-associated changes in cognitive and physical function in vervets (Chlorocebus aethiops sabaeus)

Dual declines in gait speed and cognitive performance are associated with increased risk of developing dementia. Characterizing the patterns of such impairments therefore is paramount to distinguishing healthy from pathological aging. Nonhuman primates such as vervet/African green monkeys (Chlorocebus aethiops sabaeus) are important models of human neurocognitive aging, yet the trajectory of dual decline has not been characterized. We therefore (1) assessed whether cognitive and physical performance (i.e., gait speed) are lower in older aged animals; (2) explored the relationship between performance in a novel task of executive function (Wake Forest Maze Task-WFMT) and a well-established assessment of working memory (delayed response task-DR task); and (3) examined the association between baseline gait speed with executive function and working memory at 1-year follow-up. We found (1) physical and cognitive declines with age; (2) strong agreement between performance in the novel WFMT and DR task; and (3) that slow gait is associated with poor cognitive performance in both domains. Our results suggest that older aged vervets exhibit a coordinated suite of traits consistent with human aging and that slow gait may be a biomarker of cognitive decline. This integrative approach provides evidence that gait speed and cognitive function differ across the lifespan in female vervet monkeys, which advances them as a model that could be used to dissect relationships between trajectories of dual decline over time.

Challenging the relationship of grip strength with cognitive status in older adults

OBJECTIVE

Grip strength is a widely used motor assessment in ageing research and has repeatedly been shown to be associated with cognition. It has been proposed that grip strength could enhance cognitive screening in experimental or clinical research, but this study uses multiple data-driven approaches to caution against this interpretation. Furthermore, we introduce an alternative motor assessment, comparable to grip dynamometry, but has a more robust relationship with cognition among older adults.

DESIGN

Associations between grip strength and cognition (measured with the Montreal Cognitive Assessment) were analysed cross sectionally using multivariate regression in two datasets: (1) The Irish LongituDinal Study on Ageing (TILDA; N = 5,980, community-dwelling adults ages 49-80) and (2) an experimental dataset (N = 250, community-dwelling adults aged 39-98). Additional statistical simulations on TILDA tested how ceiling effects or skewness in these variables influenced these associations for quality control.

RESULTS

Grip strength was significantly but weakly associated with cognition, consistent with previous studies. Simulations revealed this was not due to skewness/ceiling effects. Conversely, a new alternative motor assessment (functional reaching [FR]) had a stronger, more robust and more sensitive relationship with cognition compared to grip strength.

CONCLUSIONS

Grip strength should be cautiously interpreted as being associated with cognition. However, FR may have a stronger and clinically useful relationship with cognition.