Grip Strength and the Risk of Cognitive Decline and Dementia: A Systematic Review and Meta-Analysis of Longitudinal Cohort Studies

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.

Risk factors associated with the Motoric Cognitive Risk syndrome: A meta-analysis of data from a cross-national study

BACKGROUND

Identifying risk factors associated with the Motoric Cognitive Risk (MCR) syndrome (a pre-dementia syndrome) can assist in developing risk reduction strategies and interventions to delay progression to dementia. Tailored interventions require comparisons of high- and middle-income countries to determine if the same or different risk factors should be targeted. We examined risk factors associated with MCR in seven Health and Retirement Studies with harmonized measures.

METHODS

Data from adults aged ≥65 years (n = 20,036, mean age 71.2(SD 6.2)-80.1(SD 4.1)) from the U.S. Health and Retirement Study, English Longitudinal Study of Aging, Survey of Health, Aging and Retirement in Europe, China Health and Retirement Longitudinal Study, Harmonized Diagnostic Assessment of Dementia for Longitudinal Aging Study in India, Mexican Health and Aging Study, and Brazilian Longitudinal Study of Aging was included. MCR was defined as the presence of cognitive complaints and slow gait (no mobility disability and dementia). Associations of demographic [education], medical [hypertension, diabetes, heart disease, obesity, stroke, Parkinson's, falls], psychological [depressive symptoms, psychiatric problems], sensorimotor [grip strength, hearing], and behavioral factors [smoking, sedentariness, sleep], with prevalent MCR were examined using age- and sex-adjusted logistic regression models. A meta-analysis was performed to compare risk factors for MCR in high- versus middle-income countries.

RESULTS

Except for depressive symptoms and weak grip strength, different risk factor clusters were associated with individual studies. Poor sleep, hearing, weak grip, and multiple falls emerged as novel associations with MCR. When grouped by income, some risk factors (i.e., education) were associated with MCR in high- and middle-income countries. Others (i.e., obesity) were specific to high-income countries.

CONCLUSIONS

This cross-sectional, cross-national study identified new, shared, and specific risk factors associated with MCR in high- and middle-income countries, providing insights to develop public health approaches and interventions to forestall the onset of dementia in those with MCR.

SuperAgers and centenarians, dynamics of healthy ageing with cognitive resilience

Graceful healthy ageing and extended longevity is the most desired goal for human race. The process of ageing is inevitable and has a profound impact on the gradual deterioration of our physiology and health since it triggers the onset of many chronic conditions like dementia, osteoporosis, diabetes, arthritis, cancer, and cardiovascular disease. However, some people who lived/live more than 100 years called 'Centenarians" and how do they achieve their extended lifespans are not completely understood. Studying these unknown factors of longevity is important not only to establish a longer human lifespan but also to manage and treat people with shortened lifespans suffering from age-related morbidities. Furthermore, older adults who maintain strong cognitive function are referred to as "SuperAgers" and may be resistant to risk factors linked to cognitive decline. Investigating the mechanisms underlying their cognitive resilience may contribute to the development of therapeutic strategies that support the preservation of cognitive function as people age. The key to a long, physically, and cognitively healthy life has been a mystery to scientists for ages. Developments in the medical sciences helps us to a better understanding of human physiological function and greater access to medical care has led us to an increase in life expectancy. Moreover, inheriting favorable genetic traits and adopting a healthy lifestyle play pivotal roles in promoting longer and healthier lives. Engaging in regular physical activity, maintaining a balanced diet, and avoiding harmful habits such as smoking contribute to overall well-being. The synergy between positive lifestyle choices, access to education, socio-economic factors, environmental determinants and genetic supremacy enhances the potential for a longer and healthier life. Our article aims to examine the factors associated with healthy ageing, particularly focusing on cognitive health in centenarians. We will also be discussing different aspects of ageing including genomic instability, metabolic burden, oxidative stress and inflammation, mitochondrial dysfunction, cellular senescence, immunosenescence, and sarcopenia.

Association between grip strength and albuminuria in the general United States population: NHANES 2011-2014

Background

Grip strength has been shown to be associated with chronic renal insufficiency, but the relationship between grip strength and albuminuria has not been confirmed. In this study, we used NHANES data to explore the association between grip strength and albuminuria in a US population.

Methods

In this analytical study, we utilized data sourced from the National Health and Nutrition Examination Survey (NHANES), specifically spanning the years 2011 to 2014. The dataset included 9,638 participants aged 20 years or older. After adjusting for potential confounders, multiple regression models were developed to infer the interrelationship between grip strength and albumin to creatinine ratio (ACR), and subgroup analyses were conducted.

Results

After adjusting for all covariates, ACR by 0.49 mg/g [-0.49 (95% CI: -0.93, -0.04)] for each 1 kg increase in grip strength decreased. Subgroup analysis showed that gender, age, hyperlipidemia, hypertension, diabetes mellitus, smoking, alcohol consumption and body mass index did not influence the negative correlation between grip strength and albuminuria.

Conclusion

There is a negative correlation between grip strength and albuminuria in the general U.S. population.

Deficits in force production during multifinger tasks demarcate cognitive dysfunction

BACKGROUND

The multifinger force deficit (MFFD) is the decline in force generated by each finger as the number of fingers contributing to an action is increased. It has been shown to associate with cognitive status.

AIMS

The aim was to establish whether a particularly challenging form of multifinger grip dynamometry, that provides minimal tactile feedback via cutaneous receptors and requires active compensation for reaction forces, will yield an MFFD that is more sensitive to cognitive status.

METHODS

Associations between measures of motor function, and cognitive status (Montreal Cognitive Assessment [MoCA]) and latent components of cognitive function (derived from 11 tests using principal component analysis), were estimated cross-sectionally using generalized partial rank correlations. The participants (n  =  62) were community dwelling, aged 65-87.

RESULTS

Approximately half the participants were unable to complete the dynamometry task successfully. Cognitive status demarcated individuals who could perform the task from those who could not. Among those who complied with the task requirements, the MFFD was negatively correlated with MoCA scores-those with the highest MoCA scores tended to exhibit the smallest deficits, and vice versa. There were corresponding associations with latent components of cognitive function.

DISCUSSION

The results support the view that neurodegenerative processes that are a feature of normal and pathological aging exert corresponding effects on expressions of motor coordination-in multifinger tasks, and cognitive sufficiency, due to their dependence on shared neural systems.

CONCLUSIONS

The outcomes add weight to the assertion that deficits in force production during multifinger tasks are sensitive to cognitive dysfunction.

Relative associations of behavioral and physiological risks for cardiometabolic disease with cognition in bipolar disorder during mid and later-life: findings from the UK biobank

BACKGROUND

Cardiometabolic disease risk factors are disproportionately prevalent in bipolar disorder (BD) and are associated with cognitive impairment. It is, however, unknown which health risk factors for cardiometabolic disease are relevant to cognition in BD. This study aimed to identify the cardiometabolic disease risk factors that are the most important correlates of cognitive impairment in BD; and to examine whether the nature of the relationships vary between mid and later life.

METHODS

Data from the UK Biobank were available for 966 participants with BD, aged between 40 and 69 years. Individual cardiometabolic disease risk factors were initially regressed onto a global cognition score in separate models for the following risk factor domains; (1) health risk behaviors (physical activity, sedentary behavior, smoking, and sleep) and (2) physiological risk factors, stratified into (2a) anthropometric and clinical risk (handgrip strength, body composition, and blood pressure), and (2b) cardiometabolic disease risk biomarkers (CRP, lipid profile, and HbA1c). A final combined multivariate regression model for global cognition was then fitted, including only the predictor variables that were significantly associated with cognition in the previous models.

RESULTS

In the final combined model, lower mentally active and higher passive sedentary behavior, higher levels of physical activity, inadequate sleep duration, higher systolic and lower diastolic blood pressure, and lower handgrip strength were associated with worse global cognition.

CONCLUSIONS

Health risk behaviors, as well as blood pressure and muscular strength, are associated with cognitive function in BD, whereas other traditional physiological cardiometabolic disease risk factors are not.

Unlocking Cognitive Potential: Association of Sarcopenia and Mediterranean Diet on Cognitive Function in Community-Dwelling Elderly of the Dalmatian Region

The aim of this study was to determine the association between muscle strength, adherence to the Mediterranean diet (MeDi) and cognitive function in community-dwelling elderly. General data, data of body composition and anthropometric parameters, clinical and laboratory findings, cognitive test questionnaires (Mini-Mental State Examination-MMSE, Trail Making Test-TMT, Symbol Digit Modalities Test-SDMT), and nutritional assessments (Mini Nutritional Assessment-MNA, Mediterranean Diet Serving Score-MDSS) were obtained for each study participant. Handgrip strength (HS) was used as one of the key parameters for defining probable sarcopenia, among the Short Physical Performance Battery test (SPPB) (for defining physical activity) and the strength, assistance with walking, rising from a chair, climbing stairs, and falls questionnaire (SARC-F). Our cross-sectional study involved 114 participants aged ≥ 60 years, and two-thirds of the participants were female (76.3% vs. 23.7%). Probable sarcopenia was found in 34.7% of them. Using bivariate regression analysis, cognitive deficit among the sarcopenic population was associated with the following groups of collected data: (a) sociodemographic-associated factors-advanced age (OR: 1.07; p = 0.004), single marital status (OR: 3.25; p = 0.03), and low level of education (OR: 0.22; p < 0.003); (b) behavioral-associated factors-duration of institutionalization (OR: 1.05; p = 0.007), performance of heavy physical work (OR: 6.26; p = 0.001), low physical activity (OR: 0.08; p = 0.002), and risk of malnutrition (OR: 3.87; p = 0.005); (c) disease-related factors-loss of appetite (OR: 2.24; p = 0.04), information processing speed (OR: 0.88; p < 0.001), blood pressure systolic/diastolic variables (OR: 0.96/0.96; p = 0.002/0.02), medications (OR: 1.19; p = 0.005), predictive sarcopenia score ≥ 4 (OR: 3.1; p = 0.003), and low muscle strength (OR: 0.92; p = 0.002). Cognitive preservation among the sarcopenic population was associated with married status (OR: 0.23; p = 0.20), a high level of education (OR: 0.18; p = 0.002), smoking (OR: 0.33; p = 0.02), high physical activity (OR: 0.07; p < 0.001), and dietary habits using poultry (OR: 0.12; p = 0.004). The results suggest a significant association between sarcopenia and cognitive function in community-dwelling elderly, highlighting the need for regular nutritional interventions in this special population.

Digging into the intrinsic capacity concept: Can it be applied to Alzheimer's disease?

Historically, aging research has largely centered on disease pathology rather than promoting healthy aging. The World Health Organization's (WHO) policy framework (2015-2030) underscores the significance of fostering the contributions of older individuals to their families, communities, and economies. The WHO has introduced the concept of intrinsic capacity (IC) as a key metric for healthy aging, encompassing five primary domains: locomotion, vitality, sensory, cognitive, and psychological. Past AD research, constrained by methodological limitations, has focused on single outcome measures, sidelining the complexity of the disease. Our current scientific milieu, however, is primed to adopt the IC concept. This is due to three critical considerations: (I) the decline in IC is linked to neurocognitive disorders, including AD, (II) cognition, a key component of IC, is deeply affected in AD, and (III) the cognitive decline associated with AD involves multiple factors and pathophysiological pathways. Our study explores the application of the IC concept to AD patients, offering a comprehensive model that could revolutionize the disease's diagnosis and prognosis. There is a dearth of information on the biological characteristics of IC, which are a result of complex interactions within biological systems. Employing a systems biology approach, integrating omics technologies, could aid in unraveling these interactions and understanding IC from a holistic viewpoint. This comprehensive analysis of IC could be leveraged in clinical settings, equipping healthcare providers to assess AD patients' health status more effectively and devise personalized therapeutic interventions in accordance with the precision medicine paradigm. We aimed to determine whether the IC concept could be extended from older individuals to patients with AD, thereby presenting a model that could significantly enhance the diagnosis and prognosis of this disease.

Association of Serum Concentrations of Copper, Selenium, and Zinc with Grip Strength Based on NHANES 2013-2014

Increasing evidence has found metals to be strongly associated with muscle strength, but the correlations between serum copper (Cu), selenium (Se), and zinc (Zn) with grip strength in adult populations have not yet been established. We examined the linear and non-linear associations between these three metals and grip strength via multiple linear regression and restricted cubic spline (RCS) regression using data from the National Health and Nutrition Examination Survey (NHANES) 2013-2014. A higher concentration of serum Cu was monotonically linked with lower grip strength [β = - 0.004 m2 (95% CI: - 0.005, - 0.002)], and serum Zn was positively associated with grip strength [β = 0.004 m2 (95% CI: 0.002, 0.006)]. We observed a positive association between serum Se and grip strength in the unadjusted model but not in covariate-adjusted models. Interestingly, the results of RCS regression showed that serum Cu had an L-shaped non-linear association with grip strength in all participants and subgroups. We further found a linear-increased trend between serum Zn and the grip strength in all participants. There were also non-linear associations that varied across different subgroups. Taken together, serum Cu and Zn were significantly associated with grip strength, while Se was not. This study offers new evidence to help formulate a reference concentration range for serum Cu and Zn.

Higher handgrip strength is linked to higher salience ventral attention functional network segregation in older adults

Converging evidence suggests that handgrip strength is linked to cognition in older adults, and this may be subserved by shared age-related changes in brain function and structure. However, the interplay among handgrip strength, brain functional connectivity, and cognitive function remains poorly elucidated. Hence, our study sought to examine these relationships in 148 community-dwelling older adults. Specifically, we examined functional segregation, a measure of functional brain organization sensitive to ageing and cognitive decline, and its associations with handgrip strength and cognitive function. We showed that higher handgrip strength was related to better processing speed, attention, and global cognition. Further, higher handgrip strength was associated with higher segregation of the salience/ventral attention network, driven particularly by higher salience/ventral attention intra-network functional connectivity of the right anterior insula to the left posterior insula/frontal operculum and right midcingulate/medial parietal cortex. Importantly, these handgrip strength-related inter-individual differences in salience/ventral attention network functional connectivity were linked to cognitive function, as revealed by functional decoding and brain-cognition association analyses. Our findings thus highlight the importance of the salience/ventral attention network in handgrip strength and cognition, and suggest that inter-individual differences in salience/ventral attention network segregation and intra-network connectivity could underpin the handgrip strength-cognition relationship in older adults.

Comparative study of machine learning methods for modeling associations between risk factors and future dementia cases

A substantial portion of dementia risk can be attributed to modifiable risk factors that can be affected by lifestyle changes. Identifying the contributors to dementia risk could prove valuable. Recently, machine learning methods have been increasingly applied to healthcare data. Several studies have attempted to predict dementia progression by using such techniques. This study aimed to compare the performance of different machine-learning methods in modeling associations between known cognitive risk factors and future dementia cases. A subset of the AGES-Reykjavik Study dataset was analyzed using three machine-learning methods: logistic regression, random forest, and neural networks. Data were collected twice, approximately five years apart. The dataset included information from 1,491 older adults who underwent a cognitive screening process and were considered to have healthy cognition at baseline. Cognitive risk factors included in the models were based on demographics, MRI data, and other health-related data. At follow-up, participants were re-evaluated for dementia using the same cognitive screening process. Various performance metrics for all three machine learning algorithms were assessed. The study results indicate that a random forest algorithm performed better than neural networks and logistic regression in predicting the association between cognitive risk factors and dementia. Compared to more traditional statistical analyses, machine-learning methods have the potential to provide more accurate predictions about which individuals are more likely to develop dementia than others.

Bidirectional associations of high-level cognitive domains with hand motor function and gait speed in high-functioning older adults: A 7-year study

BACKGROUND

Whether age-related decline in the musculoskeletal system may contribute to a decline in cognitive performance or vice versa is unclear. Understanding the direction of their associations and the extent to which upper and lower extremities similarly predict subtle changes in high-level cognitive performance will help elucidate their mechanisms, especially that of the hand dexterity.

METHODS

We evaluated the bidirectional associations of motor performance and high-level cognitive domains in 165 highly cognitively and physically healthy older adults. Motor performance tests consisted of handgrip strength, hand dexterity, assessed with the Purdue Pegboard Test (PPT), and usual and maximum gait speeds. High-level cognitive measures included executive function and information processing speed. The Trail Making Test (TMT)B and the letter and category fluency tests (LFT and CFT) evaluated executive function, while the TMTA and Digit Symbol assessed processing speed. Measurements were taken at baseline and at 2-, 5- and 7-year follow-up.

RESULTS

Generalized linear mixed-effect models showed that baseline hand dexterity and its trajectory predicted changes in TMTB, CFT, TMTA, and Digit Symbol over time, and vice versa. Baseline maximum gait speed was associated with LFT over time and vice versa. No associations were found for handgrip and usual gait speed.

CONCLUSION

The positive bidirectional association observed both in hand dexterity and maximum gait speed with executive function performance and that of hand dexterity with processing speed over time highlights a reciprocal relationship where each factor affects the other and both factors are dependent on each other, suggesting commonality in their neural basis.

Associations of Handgrip Strength Weakness and Asymmetry with Lower Cognitive Function: Results from the National Health and Nutrition Examination Survey (2011-2014)

Background

The joint associations of handgrip strength (HGS) weakness and asymmetry with cognitive decline remain understudied in older adults.

Objective

To investigate the associations between HGS weakness, asymmetry, and lower cognitive function in a nationally representative sample of older Americans.

Methods

This cross-sectional study utilized data from the National Health and Nutrition Examination Survey 2011-2014. Weakness was defined as HGS <26 kg for men and <16 kg for women. Asymmetry was determined by calculating the ratio of dominant to non-dominant HGS. Participants with an HGS ratio <0.90 or >1.10 were classified as having any HGS asymmetry. Those with an HGS ratio >1.10 exhibited dominant HGS asymmetry, while those with an HGS ratio <0.90 displayed nondominant HGS asymmetry, respectively. Lower cognitive functioning was defined as global cognitive composite scores more than 1 standard deviation below the mean. Covariate-adjusted logistic regression models were used to analyze the associations between HGS asymmetry/weakness and lower cognitive functioning.

Results

Compared to individuals with non-weak and symmetric HGS, those with any HGS asymmetry alone and weakness alone had 1.017 (95% confidence interval [CI]: 0.707-1.463) and 1.391 (95% CI: 0.542-3.571) greater odds for cognitive decline, while co-occurrence of both HGS asymmetry and weakness was associated with 3.724 (95% CI: 1.711-8.107) greater odds for lower cognitive function after controlling for confounders.

Cnclusions

Individuals exhibiting both diminished and asymmetrical HGS demonstrated an elevated susceptibility to cognitive impairment, thereby implying that the inclusion of HGS asymmetry assessment in conjunction with weakness evaluation may enhance the accuracy of prognosticating cognitive decline.

Handgrip strength asymmetry and cognitive impairment risk: Insights from a seven-year prospective cohort study

OBJECTIVES

This study aimed to explore the links of handgrip strength and asymmetry with cognitive impairment.

DESIGN

This was a seven-year prospective cohort study.

SETTING AND PARTICIPANTS

We used data from wave 3 (2015-2017) to wave 5 (2019-2022) from the ongoing Taiwan Initiative of Geriatric Epidemiological Research (TIGER), with wave 3 as the baseline (n = 446). The study included community-dwelling participants aged 65 years or older.

MEASUREMENTS

Handgrip strength was measured, and abnormalities were determined based on handgrip strength weakness and asymmetry. Handgrip strength asymmetry was categorized into three groups at baseline based on the handgrip strength ratio (left handgrip strength/right handgrip strength). Cognitive tests evaluating global and specific cognitive domains were conducted at baseline and two biennial follow-ups. Generalized linear mixed models were utilized to assess the associations of abnormal handgrip strength with global cognition and multiple cognitive domain progression over time.

RESULTS

This study included 392 dementia-free participants, with an average age of 75.8 years and 179 (45.7%) males. Mild handgrip strength asymmetry was present in 88 participants (22.4%), while 53 (13.5%) exhibited moderate asymmetry. In men, the coexistence of low handgrip strength and handgrip strength asymmetry was linked to cognitive impairment over time. These associations were observed in global cognition (β^ = -1.76, 95% CI: -2.79 to -0.74), memory (immediate free recall: β^ = -0.67, 95% CI: -1.17 to -0.17), executive function (Trail Making Test-A: β^ = -0.54, 95% CI: -0.94 to -0.13), and attention (Digit span-forward: β^ = -1.00, 95% CI: -1.46 to -0.54).

CONCLUSIONS

This study found that individuals with reduced handgrip strength and handgrip strength asymmetry had an increased risk of cognitive impairment across various domains. Moreover, this association appears to be more pronounced among men than women. Incorporating these simple assessments into regular clinical practice improves the allocation of limited screening resources and timely clinical interventions in older adults.

Handgrip strength and upper limb functional performance measures in people over 18 years old: Analysis of relationships and influencing factors

BACKGROUND

Handgrip strength is a common, simple, and inexpensive method to measure muscle strength. On the other hand, the functional performance measurement involves a usual task which implies repeating elements between the individuals' interaction and the environment. This is fundamental for projecting their results to daily life situation.

PURPOSE

To explore the relationship between grip strength and measures of functional performance of the upper limbs (ULs) in people over 18 years of age, and to determine the influence of sociodemographic and anthropometric variables on the relationship.

STUDY DESIGN

A cross-sectional study was conducted under the analytical empirical approach, using linear associations between handgrip strength and functional performance measurement tests (correspondence analysis).

METHODS

Three hundred sixty-two male and female individuals between 18 and 91 years of age from 4 Colombian cities participated. The grip strength of both ULs measured with a digital dynamometry was associated with the Box and Block Test (BBT, manual dexterity), Nine-Hole Peg Test (NHPT, daily living tasks), and Jebsen-Taylor Hand Function Test (JJT, ability to grasp, pick up, and place). Multiple linear regression analyzes were performed to assess possible explanatory factors of a sociodemographic and anthropometric order.

RESULTS

A significant association was found between the grip strength of dominant and non-dominant ULs with all functional performance tests (ρ > 0.27 and p < .001), except for the writing and simulated feeding subtests of the JJT (ρ ≤ 0.16). An interactive effect of age was found in the relationship between grip strength and the 3 functional performance tests.

CONCLUSIONS

These results support the association between grip strength with the NHPT, JJT, and BBT measures and the interactive effect of age on the performance of all tests.

Lower handgrip strength in short-sleeper individuals with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is a frequently observed and remarkably incapacitating disorder worldwide. As a multisystem disorder, OSA has been linked to a plethora of clinical parameters though physical parameters like muscle strength have been scantily studied. Hand grip strength (HGS) is a practical marker of physical function that has been associated with mortality and an array of clinical outcomes as well as physiological parameters like sleep duration. A few seminal studies have observed no link between HGS and OSA severity while no studies evaluated the relationship between objectively determined sleep duration and HGS in OSA.

OBJECTIVE

The present study aimed to evaluate the HGS indices among both OSA severity groups and objectively determined sleep duration groups in OSA.

METHODS

111 treatment-naïve mostly middle-aged individuals with OSA (86 males) were recruited in a tertiary sleep center. Three OSA severity groups were determined by the Apnea-Hypopnea Index while three sleep duration groups were objectively determined by Total Sleep Time (TST). Dominant and non-dominant maximum and average HGS were calculated using a digital hand dynamometer.

RESULTS

Short-sleeper individuals with OSA were found to have lower HGS indices than intermediate or sufficient sleepers with OSA while no differences in HGS indices among OSA severity groups were observed. All HGS indices correlated with TST.

CONCLUSIONS

Future insights can be gleaned from the present results regarding the conceivably transdiagnostic relationship between sleep duration and HGS as well as the potential use of HGS as a marker in OSA.

The Role of Different Weakness Cut-Points for Future Cognitive Impairment in Older Americans

OBJECTIVES

New absolute and normalized handgrip strength (HGS) cut-points may not yield similar predictive value for cognitive performance. We sought to determine the associations of (1) each absolute and normalized weakness cut-point, and (2) compounding weakness on future cognitive impairment in older Americans.

DESIGN

Longitudinal panel.

SETTING AND PARTICIPANTS

The analytic sample included 11,116 participants aged ≥65 years from the 2006 to 2018 waves of the Health and Retirement Study. Participants from the Health and Retirement Study completed detailed interviews that included physical measures and core interviews.

METHODS

The modified Telephone Interview of Cognitive Status assessed cognitive function and persons scoring <11 were classified as having a cognitive impairment. A handgrip dynamometer measured HGS. Men were considered weak if their HGS was <35.5 kg (absolute), <0.45 kg/kg (body mass normalized), or <1.05 kg (body mass index normalized), whereas women were classified as weak if their HGS was <20.0 kg, <0.337 kg/kg, or <0.79 kg. Compounding weakness included those below 1, 2, or all 3 cut-points. Generalized estimating equations quantified the associations.

RESULTS

Persons considered weak under the absolute cut-point had 1.62 (95% CI 1.34-1.96) greater odds for future cognitive impairment, but no significant associations were observed for those classified as weak under the body mass [odds ratio (OR) 1.12, CI 0.91-1.36] and body mass index normalized (OR 1.17, CI 0.95-1.43) cut-points. Older Americans below all 3 weakness cut-points had 1.47 (CI 1.15-1.88) greater odds for future cognitive impairment, but no significant associations were found for persons classified as weak under 1 (OR 1.08, CI 0.83-1.42) or 2 (OR 1.19, CI 0.91-1.55) cut-points.

CONCLUSIONS AND IMPLICATIONS

Our findings suggest that each weakness cut-point has differential prognostic value for future cognitive impairment, and aggregating weakness cut-points may improve their predictive utility. Consideration should be given to how weakness categories are uniquely linked to cognitive function.

Sex-modified association between grip strength and mild cognitive impairment: a cross-sectional and follow-up study in rural China

BACKGROUND

The sex difference in the association between grip strength and mild cognitive impairment (MCI) remains controversial and unclear.

METHODS

This is a part of a chronic disease cohort study conducted in rural areas, Fuxin, Liaoning Province, China. At the baseline survey, a total of 2633 participants aged 35- 85 were included in the cross-sectional study. Handgrip strength (HGS, kg) was measured by a dynamometer (Jamar +). MCI were assessed using the Chinese version of the Montreal Cognitive Assessment-Basic (MOCA-BC). Then, a total of 1667 cognitively normal individuals (NCs) were planed to follow up and to assess the incident MCI after two years. We used logistic regression to examine the association between HGS (as a continuous variable and quintiles) and MCI and analyzed the interaction between sex and HGS on MCI. Models stratified by sex were adjusted for demographic information (age, ethnicity, education, marital status, income, physical labor level), modifiable risk factors (body mass index, smoking, drinking) and disease history (hypertension, diabetes, dyslipidemia and coronary heart disease). Baseline MOCA-BC scores were additionally adjusted in the longitudinal study.

RESULTS

In the cross-sectional study, participants were on average 56.6 ± 9.8 years, and 1713 (65.1%) were females. In the cohort study, 743 individuals were followed up with an average age of 55.9 ± 9.6 years, which included 530 (71.3%) females. The cumulative incidence of MCI over a two-year period was 17.1%. In the cross-sectional study, compared to the highest quintile of HGS, the lowest HGS was associated with higher risk of MCI in males (odds ratio [OR]: 2.66; 95% confidence interval [CI]: 1.54, 4.64) and females (OR: 1.70; 95% CI: 1.17, 2.49) with adjustment of potential confounding factors. In the cohort study, compared to the highest quintile of HGS, the lowest HGS was associated with an increased risk of incident MCI in females (OR: 3.93; 95% CI: 1.39, 13.01) but not in males (OR: 0.56; 95% CI: 0.11, 2.94, P for interaction = 0.015).

CONCLUSIONS

Lower grip strength is a risk factor for mild cognitive impairment and predicts a higher risk of MCI in females.

Does muscle strength predict working memory? A cross-sectional fNIRS study in older adults

Objective

Previous research has primarily focused on the association between muscle strength and global cognitive function in older adults, while the connection between muscle strength and advanced cognitive function such as inhibition and working memory (WM) remains unclear. This study aimed to investigate the relationship among muscle strength, WM, and task-related cortex hemodynamics.

Methods

We recruited eighty-one older adults. Muscle strength was measured using a grip and lower limb strength protocol. We measured the WM performance by using reaction time (RT) and accuracy (ACC) in the N-back task and the cortical hemodynamics of the prefrontal cortex (PFC) by functional near-infrared spectroscopy (fNIRS).

Results

We found positive correlations between grip strength (p < 0.05), 30-s sit-up (p < 0.05) and ACC, negative correlation between grip strength (p < 0.05) and RT. Furthermore, we observed positive correlations between grip strength and the level of oxygenated hemoglobin (HbO2) in dorsolateral prefrontal cortex, frontopolar area, ventrolateral prefrontal cortex (p < 0.05), and negative correlations between grip strength and the level of deoxygenated hemoglobin (Hb) in left dorsolateral prefrontal cortex, frontopolar area, left ventrolateral prefrontal cortex (p < 0.05). Additionally, we noticed positive correlations between RT and the level of Hb in left dorsolateral prefrontal cortex, right frontopolar area (p < 0.05), and negative correlations between RT and the level of HbO2 in left dorsolateral prefrontal cortex, frontopolar area (p < 0.05). However, the cortical hemodynamics did not mediate the relationship between muscle strength and WM performance (RT, ACC).

Conclusion

The grip strength of older adults predicted WM in the cross-section study. The level of hemodynamics in PFC can serve as a predictor of WM.

Handgrip strength, physical activity and incident mild cognitive impairment and dementia

OBJECTIVE

We analyzed the mediating role of handgrip strength in the association between moderate to vigorous physical activity and incident mild cognitive impairment and dementia.

METHODS

We used prospective data from 14 European countries participating in the Survey of Health, Ageing, and Retirement in Europe. 19,686 participants free of dementia and mild cognitive impairment (64.9 ± 8.7 years) were followed up for a mean of 10.2 years. Moderate to vigorous physical activity was self-reported, and handgrip strength was assessed with a dynamometer. Mild cognitive impairment was defined as 1.5 standard deviations below the mean of the standardized global cognition score, while dementia was determined by physician diagnosis. Gender, age, country, education, presence of chronic diseases, depressive symptoms, limitations in activities of daily living, body mass index, and baseline cognitive levels were used as covariates. Cox proportional hazards as well as mediation models were used.

RESULTS

Moderate to vigorous physical activity for at least 1 day per week was independently associated with lower incident mild cognitive impairment (HR: 0.85; 95%CI: 0.74-0.98). A 10 % increase in handgrip strength was associated a 6 % lower hazard for incident mild cognitive impairment (0.94; 0.92-0.97) and 5 % lower hazard for incident dementia (0.95; 0.93-0.98). Handgrip strength partly mediated the association of moderate to vigorous physical activity with mild cognitive impairment (Coefficient: 0.03; 95%CI: 0.01-0.05; 17.9 %).

CONCLUSIONS

Physical activity is independently associated with a lower incidence of mild cognitive impairment.

Protracted CLN3 Batten disease in mice that genetically model an exon-skipping therapeutic approach

Genetic mutations that disrupt open reading frames and cause translation termination are frequent causes of human disease and are difficult to treat due to protein truncation and mRNA degradation by nonsense-mediated decay, leaving few options for traditional drug targeting. Splice-switching antisense oligonucleotides offer a potential therapeutic solution for diseases caused by disrupted open reading frames by inducing exon skipping to correct the open reading frame. We have recently reported on an exon-skipping antisense oligonucleotide that has a therapeutic effect in a mouse model of CLN3 Batten disease, a fatal pediatric lysosomal storage disease. To validate this therapeutic approach, we generated a mouse model that constitutively expresses the Cln3 spliced isoform induced by the antisense molecule. Behavioral and pathological analyses of these mice demonstrate a less severe phenotype compared with the CLN3 disease mouse model, providing evidence that antisense oligonucleotide-induced exon skipping can have therapeutic efficacy in treating CLN3 Batten disease. This model highlights how protein engineering through RNA splicing modulation can be an effective therapeutic approach.

Clinical Significance of Physical Frailty in Subjects With Subjective Cognitive Decline: A Prospective Study With Amyloid PET Data

BACKGROUND AND PURPOSE

Physical frailty is known to be closely associated with cognitive impairment and to be an early sign of Alzheimer's disease. We aimed to understand the characteristics of physical frailty and define factors associated with physical frailty in subjects with subjective cognitive decline (SCD) by analyzing amyloid data.

METHODS

We prospectively enrolled subjects with SCD from a cohort study to identify predictors for the clinical progression to mild cognitive impairment or dementia from SCD (CoSCo). All of the subjects underwent brain magnetic resonance imaging, and brain amyloid positron-emission tomography (PET) to detect amyloid beta plaques. Self-reported exhaustion, handgrip strength, and gait speed were used to measure physical frailty.

RESULTS

Of 120 subjects with SCD, 26 (21.7%) were amyloid-positive in PET. Female (odds ratio [OR]=3.79, p=0.002) and amyloid-PET-positive (OR=3.80, p=0.008) subjects with SCD were at high risks of self-reported exhaustion. Amyloid PET positivity (OR=3.22, p=0.047) and high burden from periventricular white-matter hyperintensity (OR=3.34, 95% confidence interval=1.18-9.46, p=0.023) were significantly associated with a weaker handgrip. The subjects with SCD with self-reported exhaustion and weaker handgrip presented with lower cognitive performance in neuropsychological tests, especially for information processing speed and executive function. Subjects with a slower gait performed worse in visual memory function tests.

CONCLUSIONS

Amyloid PET positivity was associated with a higher risk of self-reported exhaustion and weaker handgrip in subjects with SCD. The subjects with SCD and physical frailty also performed worse in neuropsychological tests.

Look into my eyes: What can eye-based measures tell us about the relationship between physical activity and cognitive performance?

BACKGROUND

There is a growing interest to understand the neurobiological mechanisms that drive the positive associations of physical activity and fitness with measures of cognitive performance. To better understand those mechanisms, several studies have employed eye-based measures (e.g., eye movement measures such as saccades, pupillary measures such as pupil dilation, and vascular measures such as retinal vessel diameter) deemed to be proxies for specific neurobiological mechanisms. However, there is currently no systematic review providing a comprehensive overview of these studies in the field of exercise-cognition science. Thus, this review aimed to address that gap in the literature.

METHODS

To identify eligible studies, we searched 5 electronic databases on October 23, 2022. Two researchers independently extracted data and assessed the risk of bias using a modified version of the Tool for the assEssment of Study qualiTy and reporting in EXercise (TESTEX scale, for interventional studies) and the critical appraisal tool from the Joanna Briggs Institute (for cross-sectional studies).

RESULTS

Our systematic review (n = 35 studies) offers the following main findings: (a) there is insufficient evidence available to draw solid conclusions concerning gaze-fixation-based measures; (b) the evidence that pupillometric measures, which are a proxy for the noradrenergic system, can explain the positive effect of acute exercise and cardiorespiratory fitness on cognitive performance is mixed; (c) physical training- or fitness-related changes of the cerebrovascular system (operationalized via changes in retinal vasculature) are, in general, positively associated with cognitive performance improvements; (d) acute and chronic physical exercises show a positive effect based on an oculomotor-based measure of executive function (operationalized via antisaccade tasks); and (e) the positive association between cardiorespiratory fitness and cognitive performance is partly mediated by the dopaminergic system (operationalized via spontaneous eye-blink rate).

CONCLUSION

This systematic review offers confirmation that eye-based measures can provide valuable insight into the neurobiological mechanisms that may drive positive associations between physical activity and fitness and measures of cognitive performance. However, due to the limited number of studies utilizing specific methods for obtaining eye-based measures (e.g., pupillometry, retinal vessel analysis, spontaneous eye blink rate) or investigating a possible dose-response relationship, further research is necessary before more nuanced conclusions can be drawn. Given that eye-based measures are economical and non-invasive, we hope this review will foster the future application of eye-based measures in the field of exercise-cognition science.

The association of aerobic and muscular fitness with cognitive impairment: Findings from a nationally representative survey

This study aimed to characterize the combined association between cardiorespiratory fitness (CRF), muscular strength, and cognitive outcomes in middle-aged and older adults from low and middle-income countries (LMICs). We analyzed cross-sectional, population-based data from adults aged 50 years or older from six LMICs. Mild cognitive impairment (MCI) was defined according to the National Institute on Aging-Alzheimer's Association criteria. Estimated CRF (eCRF) was calculated using previously validated, sex-specific equations. Handgrip strength (HS) was used as an indicator of muscular strength. We used linear and robust Poisson regression models to examine the associations between eCRF, HS, and MCI. Data from 28,339 adults (63.1 [9.5] years) were analyzed. Participants with low eCRF (PR: 1.45; 95%CI: 1.11, 1.90) and HS (PR: 1.92; 95%CI: 1.79, 2.04) were more prone to have MCI. Participants with low HS showed higher likelihood of MCI than those with preserved HS through the CRF range; however, this difference was not seen among highly fit individuals (10 METs or higher). Each 1-MET (PR: 0.77; 95%CI: 0.67, 0.86) and 5-kgf (PR: 0.63; 95%CI: 0.48, 0.79) increase was associated with a reduction in the likelihood of MCI. eCRF and HS were strongly and independently associated with MCI in middle-aged and older adults.

The direct and mediating effects of cognitive impairment on the occurrence of falls: a cohort study based on community-dwelling old adults

Background

Cognitive impairment has been reported to be associated with falls in older adults. However, the complex relationship among falls, cognitive impairment and its associated factors, which could be targeted with specific interventions, remains to be elucidated. This study aimed to examine the direct effects of cognitive impairment on falls, to identify the factors associated with cognitive impairment and to explore the mediation role of cognitive impairment in the association of fall with cognition related factors.

Methods

This 1-year follow-up cohort study enrolled old adults aged 60  years or over. Information about demographic and anthropometric characteristics, fall outcomes, function and nutritional status were collected through face-to-face interview. Cognitive function was evaluated by the Montreal Cognitive Assessment (MoCA). Multivariable regression analyses were used to test the association between cognitive impairment and falls and to identify the factors related to cognitive impairment. Additionally, we conduct causal mediation analyses to estimate the mediation effects of cognitive impairment in the pathways of fall occurrence.

Results

Of the 569 participants included in this study, 366 (64.32%) had cognitive impairment, 96 (16.87%) had fall history in the past 1  year, 81 (14.24%) experienced fall and 47 (8.26%) received treatment because of falling during the 1-year follow-up. The association between cognitive impairment and 1-year fall risk was confirmed after adjusting for multiple covariates [odds ratio (OR):2.03, 95% confidence interval (CI): 1.13-3.80]. IADL disability, depression and low grip strength were associated with a higher prevalence of cognitive impairment. While overweight, higher education and higher income level were found to be related to a lower risk of cognitive impairment. Among these associated factors, cognitive impairment mediated the positive association of falling with IADL ability and depression, and a negative relationship with education and income level.

Conclusion

Our study not only confirmed the direct influence of cognitive impairment on fall risk in older adults, but also suggested a mediating role that cognitive impairment played in the pathways of fall occurrence. Our finding could help develop more specific interventions for fall prevention.

Longitudinal grip strength is associated with susceptibility to the Sound Induced Flash Illusion in older adults

The precision of temporal multisensory integration is associated with specific aspects of physical functioning in ageing, including gait speed and incidents of falling. However, it is unknown if such an association exists between multisensory integration and grip strength, an important index of frailty and brain health and predictor of disease and mortality in older adults. Here, we investigated whether temporal multisensory integration is associated with longitudinal (eight-year) grip strength trajectories in a large sample of 2,061 older adults (mean age = 64.42 years, SD = 7.20; 52% female) drawn from The Irish Longitudinal Study on Ageing (TILDA). Grip strength (kg) for the dominant hand was assessed with a hand-held dynamometer across four testing waves. Longitudinal k-means clustering was applied to these data separately for sex (male, female) and age group (50-64, 65-74, 75+ years). At wave 3, older adults participated in the Sound Induced Flash Illusion (SIFI), a measure of the precision of temporal audio-visual integration, which included three audio-visual stimulus onset asynchronies (SOAs): 70, 150 and 230 ms. Results showed that older adults with a relatively lower (i.e., weaker) grip strength were more susceptible to the SIFI at the longer SOAs compared to those with a relatively higher (i.e., stronger) grip strength (p <.001). These novel findings suggest that older adults with relatively weaker grip strength exhibit an expanded temporal binding window for audio-visual events, possibly reflecting a reduction in the integrity of the central nervous system.

Association between handgrip strength asymmetry and cognitive function across ethnicity in rural China: a cross-sectional study

Background

Recently, the association between handgrip strength (HGS) asymmetry and cognition has been revealed, but evidences are still scarce. Particularly, the association between asymmetric HGS and cognitive performance in various cognitive domains is unclear and whether this association is stable across ethnic groups is unknown.

Method

The population was from a longitudinal study in rural areas of Fuxin, Liaoning, China. The Chinese version of Montreal Cognitive Assessment-Basic (MOCA-BC) was used to evaluate the cognitive function. The HGS ratio was calculated as maximal non-dominant HGS divided by maximal dominant HGS. HGS ratio <0.9 or >1.1 was classified as asymmetric dominant/non-dominant HGS, respectively. Generalized linear models were used to analyze the relationship between asymmetric HGS and cognitive function adjusted for HGS, handedness, wave, age, sex, education, ethnicity, smoking, drinking, physical labor level, BMI, hypertension, diabetes and dyslipidemia.

Result

A total of 2,969 participants ≥50 years were included in this study. Adjusted for HGS and other confunding variables, there was an inverted U-shaped association between HGS ratio and MoCA-BC scores (P _non-linear = 0.004). The association between HGS ratio and MoCA-BC scores was inconsistent among ethnic groups (P _interaction = 0.048). In Han, only asymmetric non-dominant HGS was associated with lower cognitive scores [β = -0.67, 95% confidence interval (CI): -1.26 ∼-0.08, P = 0.027]; in Mongolians, asymmetric dominant HGS(β = -0.60, 95% CI: -1.35 ∼ 0.15, P = 0.115) and asymmetric non-dominant HGS (β = -0.56, 95% CI: -1.42 ∼ 0.31, P = 0.206) were all associated with lower cognitive scores, although no statistical significance was found. Asymmetric non-dominant HGS and lower HGS, but not asymmetric dominant HGS were all independently associated with impairment of Delayed Recall (OR = 1.35, 95% CI: 1.05 ∼ 1.74; OR _{per 5 kg decrease} = 1.10, 95% CI: 1.01 ∼ 1.21) and Fluency (OR = 1.43, 95% CI: 1.15 ∼ 1.78; OR _{per 5 kg decrease} = 1.10, 95% CI: 1.02 ∼ 1.19). Both asymmetric dominant HGS (OR = 1.34, 95% CI: 1.07 ∼ 1.67) and lower HGS (OR _{per 5 kg decrease} = 1.21, 95% CI: 1.10 ∼ 1.32) were associated with impairment of visuoperception.

Conclusion

HGS and HGS asymmetry were all independently related to lower global cognitive performance. The association between HGS asymmetry and cognitive function varies among ethnic groups.

The Relationship between Handgrip Strength, Timed Up-and-Go, and Mild Cognitive Impairment in Older People during COVID-19 Pandemic Restrictions

The COVID-19 lockdown restrictions affected physical performance and cognitive function in older people as they were confined to their homes. There is an association between physical and cognitive functions. Mild Cognitive Impairment (MCI) is a condition that risks progressing to dementia. This study aimed to identify the relationship between handgrip strength (HGS), Timed Up-and-Go (TUG), and MCI in older people during the COVID-19 pandemic restrictions. The cross-sectional study recruited 464 eligible participants for an interview and anthropometric measurement. The Montreal Cognitive Assessment-Basic (MoCA-B), HGS, and TUG were measured in addition to demographic and health characteristics. A total of 398 participants (85.8%) were found to have MCI when screened with the MoCA-B. Their mean age was 71.09 ± 5.81 years. Forward multiple regression analysis demonstrated that HGS (β = 0.032, p < 0.001), education level (β = 2.801, p < 0.001), TUG (β = -0.022, p = 0.013), Thai Geriatric Depression Score, TGDS (β = -0.248, p = 0.011), and age (β = -1.677, p = 0.019) were associated with MCI. A decrease in HGS and an increased TUG might allow for the early detection of MCI and promote physical training in order to reduce the risk of MCI. Further studies can investigate multidomain indicators for MCI, for example, fine motor skills and pinch strength as components of the motor abilities.

Head posture mediates the association of cognition with hand grip and pinch strength in older adults: an examination using structural equation modeling

BACKGROUND

The association of cognition with hand grip and pinch strength has been well-recognized in older adults. The authors sought to explore: (1) associations among forward head posture (FHP), cognition, and hand grip and pinch strength in older adults; and (2) the mediator role of FHP in these pathways using structural equation modeling (SEM).

METHODS

This cross-sectional study included 88 older adults (70.5% male; mean age = 68.75±3.87 years). Cognition was assessed by the Mini-Mental State Examination (MMSE), head posture by the Craniovertebral Angle (CVA) obtained from photographic analysis, hand grip strength by a handheld dynamometer, and pinch strength by a pinch meter. Using the two SEMs, a potential mediator role of the CVA was investigated. While the MMSE was addressed as an independent variable in both models, hand grip and pinch strength were addressed as dependent variables in model 1 and model 2, respectively.

RESULTS

The correlations between the CVA and MMSE (r = 0.310), hand grip strength (r = 0.370), and pinch strength (r = 0.274 to 0.292) were statistically significant (p < 0.001). In addition, significant associations were found between the MMSE and hand grip and pinch strength, ranging from 0.307 to 0.380 (p < 0.001). The mediation analysis showed that the standardized total (β = 0.41, p < 0.001) and indirect (mediated) effects (β = 0.12, p = 0.008) of the MMSE on hand grip strength were significant in model (1) The results were similar for model (2) The standardized total (β = 0.39, p = 0.001) and indirect effects (β = 0.10, p = 0.026) of the MMSE on pinch strength were significant. As a partial mediator in both models, the CVA explained 29% and 26% of the total effect in models 1 and 2, respectively.

CONCLUSIONS

The CVA was associated with the MMSE, hand grip strength, and pinch strength, and CVA partially mediates the association of the MMSE with grip and pinch strength in older adults, indicating that cognition had an effect on grip and pinch strength through an indirect path via head posture. This finding reveals that evaluating head posture and providing corrective therapeutic interventions as needed may be beneficial in reducing the negative impact of decreased cognition on motor functions in older adults.

Nativity differences in the relationship between handgrip strength and cognitive impairment in older Mexican Americans over 20 years of follow-up

PURPOSE

To examine nativity differences in the relationship between handgrip strength (HGS) and cognitive impairment among Mexican Americans aged ≥ 65 years with normal or high cognitive function at baseline over a 20-year period.

METHODS

Prospective cohort study of 2,155 non-institutionalized Mexican Americans aged ≥ 65 years from the Hispanic Established Population for the Epidemiological Study of the Elderly) who scored ≥ 21 in the Mini Mental State Examination (MMSE) at baseline. Measures included socio-demographics, body mass index, medical conditions, depressive symptoms, physical function, disability, HGS quartiles (sex-adjusted), and MMSE. We used generalized estimating equation models to estimate the odds ratio (OR) and 95% Confidence Interval (CI) of cognitive impairment (MMSE < 21) as a function of HGS quartile by nativity and adjusted for covariates.

RESULTS

US-born and foreign-born participants in the 4th quartile (highest) of HGS at baseline had lower odds of cognitive impairment over time compared with those in the 1st (lowest) HGS quartile (OR=0.95, 95% CI=0.90-0.99 and OR=0.93, 95% CI=0.89-0.98, respectively), after controlling for all covariates. When we analyzed HGS quartiles as time-varying, we found that US-born participants in the 3rd and 4th HGS quartile had 25% and 30% lower odds of cognitive impairment, respectively, while foreign-born participants in the 3rd and 4th HGS quartile had 27% and 49% lower odds of cognitive impairment over time, respectively, after controlling for all covariates.

CONCLUSION

Foreign-born older Mexican Americans who performed high in HGS experienced 7% lower odds of cognitive impairment over time compared with US-born older Mexican Americans.

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.

Grip strength, gait speed, and trajectories of cognitive function in community-dwelling older adults: A prospective study

Introduction

This study investigated whether grip strength and gait speed predict cognitive aging trajectories and examined potential sex-specific associations.

Methods

Community-dwelling older adults (n = 19,114) were followed for up to 7 years, with regular assessment of global function, episodic memory, psychomotor speed, and executive function. Group-based multi-trajectory modeling identified joint cognitive trajectories. Multinomial logistic regression examined the association of grip strength and gait speed at baseline with cognitive trajectories.

Results

High performers (14.3%, n = 2298) and low performers (4.0%, n = 642) were compared to the average performers (21.8%, n = 3492). Grip strength and gait speed were positively associated with high performance and negatively with low performance (P-values < 0.01). The association between grip strength and high performance was stronger in women (interaction P < 0.001), while gait speed was a stronger predictor of low performance in men (interaction P < 0.05).

Discussion

Grip strength and gait speed are associated with cognitive trajectories in older age, but with sex differences.

Highlights

There is inter-individual variability in late-life cognitive trajectories.Grip strength and gait speed predicted cognitive trajectories in older age.However, sex-specific associations were identified.In women, grip strength strongly predicted high, compared to average, trajectory.In men, gait speed was a stronger predictor of low cognitive performance trajectory.

Association of Sarcopenia and Its Defining Components with the Degree of Cognitive Impairment in a Memory Clinic Population

BACKGROUND

Sarcopenia and cognitive impairment are two leading causes of disabilities.

OBJECTIVE

The objective was to examine the prevalence of sarcopenia and investigate the association between sarcopenia diagnostic components (muscle strength, muscle mass, and physical performance) and cognitive impairment in memory clinic patients.

METHODS

368 patients were included (age 59.0±7.25 years, women: 58.7%), displaying three clinical phenotypes of cognitive impairments, i.e., subjective cognitive impairment (SCI, 57%), mild cognitive impairment (MCI, 26%), and Alzheimer's disease (AD, 17%). Sarcopenia was defined according to diagnostic algorithm recommended by the European Working Group on Sarcopenia in Older People. Components of sarcopenia were grip strength, bioelectrical impedance analysis, and gait speed. They were further aggregated into a score (0-3 points) by counting the numbers of limited components. Multi-nominal logistic regression was applied.

RESULTS

Probable sarcopenia (i.e., reduced grip strength) was observed in 9.6% of the patients, and 3.5% were diagnosed with sarcopenia. Patients with faster gait speed showed less likelihood of MCI (odds ratio [OR]: 0.24, 95% confidence interval [CI]: 0.06-0.90) and AD (OR: 0.12, 95% CI: 0.03-0.60). One or more limited sarcopenia components was associated with worse cognitive function. After adjusting for potential confounders, the association remained significant only for AD (OR 4.29, 95% CI 1.45-11.92).

CONCLUSION

The results indicate a connection between the sarcopenia components and cognitive impairments. Limitations in the sarcopenia measures, especially slow walking speed, were related to poorer cognitive outcomes. More investigationsare required to further verify the causal relationship between sarcopenia and cognitive outcomes.

Handgrip Strength Is Related to Hippocampal and Lobar Brain Volumes in a Cohort of Cognitively Impaired Older Adults with Confirmed Amyloid Burden

BACKGROUND

Strength and mobility are essential for activities of daily living. With aging, weaker handgrip strength, mobility, and asymmetry predict poorer cognition. We therefore sought to quantify the relationship between handgrip metrics and volumes quantified on brain magnetic resonance imaging (MRI).

OBJECTIVE

To model the relationships between handgrip strength, mobility, and MRI volumetry.

METHODS

We selected 38 participants with Alzheimer's disease dementia: biomarker evidence of amyloidosis and impaired cognition. Handgrip strength on dominant and non-dominant hands was measured with a hand dynamometer. Handgrip asymmetry was calculated. Two-minute walk test (2MWT) mobility evaluation was combined with handgrip strength to identify non-frail versus frail persons. Brain MRI volumes were quantified with Neuroreader. Multiple regression adjusting for age, sex, education, handedness, body mass index, and head size modeled handgrip strength, asymmetry and 2MWT with brain volumes. We modeled non-frail versus frail status relationships with brain structures by analysis of covariance.

RESULTS

Higher non-dominant handgrip strength was associated with larger volumes in the hippocampus (p = 0.02). Dominant handgrip strength was related to higher frontal lobe volumes (p = 0.02). Higher 2MWT scores were associated with larger hippocampal (p = 0.04), frontal (p = 0.01), temporal (p = 0.03), parietal (p = 0.009), and occipital lobe (p = 0.005) volumes. Frailty was associated with reduced frontal, temporal, and parietal lobe volumes.

CONCLUSION

Greater handgrip strength and mobility were related to larger hippocampal and lobar brain volumes. Interventions focused on improving handgrip strength and mobility may seek to include quantified brain volumes on MR imaging as endpoints.

Grip force as a functional window to somatosensory cognition

Analysis of grip force signals tailored to hand and finger movement evolution and changes in grip force control during task execution provide unprecedented functional insight into somatosensory cognition. Somatosensory cognition is the basis of our ability to act upon and to transform the physical world around us, to recognize objects on the basis of touch alone, and to grasp them with the right amount of force for lifting and manipulating them. Recent technology has permitted the wireless monitoring of grip force signals recorded from biosensors in the palm of the human hand to track and trace human grip forces deployed in cognitive tasks executed under conditions of variable sensory (visual, auditory) input. Non-invasive multi-finger grip force sensor technology can be exploited to explore functional interactions between somatosensory brain mechanisms and motor control, in particular during learning a cognitive task where the planning and strategic execution of hand movements is essential. Sensorial and cognitive processes underlying manual skills and/or hand-specific (dominant versus non-dominant hand) behaviors can be studied in a variety of contexts by probing selected measurement loci in the fingers and palm of the human hand. Thousands of sensor data recorded from multiple spatial locations can be approached statistically to breathe functional sense into the forces measured under specific task constraints. Grip force patterns in individual performance profiling may reveal the evolution of grip force control as a direct result of cognitive changes during task learning. Grip forces can be functionally mapped to from-global-to-local coding principles in brain networks governing somatosensory processes for motor control in cognitive tasks leading to a specific task expertise or skill. Under the light of a comprehensive overview of recent discoveries into the functional significance of human grip force variations, perspectives for future studies in cognition, in particular the cognitive control of strategic and task relevant hand movements in complex real-world precision task, are pointed out.

Measurement of hand grip strength: A cross-sectional study of two dynamometry devices

Background

Grip strength has been identified as an important indicator of health status and predictor of clinical outcomes. The gold standard for measuring grip strength is the JAMAR® Hydraulic Hand Dynamometer. Less expensive dynamometers are available but have not been validated within a hospital setting.

Objectives

To validate the Camry Digital Handgrip Dynamometer (Model EH101) against the validated JAMAR® Dynamometer (Model J00105) in a hospital population.

Methods

A cross-sectional observational study with a randomised single-blind cross-over component was conducted on consenting adult patients admitted to general hospital wards. The best of three measurements taken using the dominant hand was used for analysis.

Results

Fifty-one participants (median [interquartile range] age 42 [30–58] years; n = 27 [52.9%] female) were included. The mean difference between the Jamar® and Camry measurements was 1.9 kg ± 3.6 kg (t-value 0.9; p = 0.4). There was a strong positive correlation between the Jamar® and the Camry devices (R = 0.94; r² = 0.88; p < 0.0001). Excellent agreement was found between Jamar® and Camry measurements (interclass correlational coefficient 0.97, 95% CI 0.94–0.99, p < 0.0001). Hand dominance significantly affected the agreement between devices (p = 0.002).

Conclusions

The Camry Digital Handgrip Dynamometer is a valid tool for assessing grip strength in hospitalised adult patients.

Clinical implications

The Camry Digital Handgrip Dynamometer could be used as an inexpensive tool to measure grip strength.

Associations of grip strength, walking pace, and the risk of incident dementia: A prospective cohort study of 340212 participants

INTRODUCTION

Grip strength and walking pace have been linked to cognitive dysfunction. Their relationships, however, demand further clarification as the evidence is derived primarily from less-comprehensive investigations.

METHODS

A total of 340212 UK Biobank participants without dementia and cardiovascular diseases at baseline were analyzed. Cox proportional hazard models assessed the longitudinal associations.

RESULTS

Over a mean follow-up of 8.51 ± 2.68 years, 2424 incident dementia cases were documented. A 5 kg increment of absolute grip strength was associated with lower risks of all-cause dementia (hazard ratio [HR] 0.857), Alzheimer's disease (HR 0.874), and vascular dementia (HR 0.788). The patterns of associations remained similar when grip strength was expressed in relative terms and quintiles. A slow walking pace demonstrated consistent associations with increased risks of all dementia types.

DISCUSSION

Our findings provide amplified evidence and suggest that muscle fitness, reflected by objective grip strength measures and self-reported walking pace, may be imperative for estimating the risks of dementia.

Combination of gait speed and grip strength to predict cognitive decline and dementia

Introduction

To determine whether slowed gait and weakened grip strength independently, or together, better identify risk of cognitive decline or dementia.

Methods

Time to walk 3 meters and grip strength were measured in a randomized placebo-controlled clinical trial involving community-dwelling, initially cognitively healthy older adults (N = 19,114).

Results

Over a median 4.7 years follow-up, slow gait and weak grip strength at baseline were independently associated with risk of incident dementia (hazard ratio [HR] = 1.44, 95% confidence interval [CI]: 1.19-1.73; and 1.24, 95% CI: 1.04-1.50, respectively) and cognitive decline (HR = 1.38, 95% CI: 1.26-1.51; and 1.04, 95% CI: 0.95-1.14, respectively) and when combined, were associated with 79% and 43% increase in risk of dementia and cognitive decline, respectively. Annual declines in gait and in grip over time showed similar results.

Discussion

Gait speed and grip strength are low-cost markers that may be useful in the clinical setting to help identify and manage individuals at greater risk, or with early signs, of dementia, particularly when measured together.

Highlights

Grip strength and gait speed are effective predictors and markers of dementia.Dementia risk is greater than cognitive decline risk with declines in gait or grip.Decline in gait speed, more so than in grip strength, predicts greater dementia risk.Greater risk prediction results from combining grip strength and gait speed.

Associations between grip strength, brain structure, and mental health in > 40,000 participants from the UK Biobank

BACKGROUND

Grip strength is a widely used and well-validated measure of overall health that is increasingly understood to index risk for psychiatric illness and neurodegeneration in older adults. However, existing work has not examined how grip strength relates to a comprehensive set of mental health outcomes, which can detect early signs of cognitive decline. Furthermore, whether brain structure mediates associations between grip strength and cognition remains unknown.

METHODS

Based on cross-sectional and longitudinal data from over 40,000 participants in the UK Biobank, this study investigated the behavioral and neural correlates of handgrip strength using a linear mixed effect model and mediation analysis.

RESULTS

In cross-sectional analysis, we found that greater grip strength was associated with better cognitive functioning, higher life satisfaction, greater subjective well-being, and reduced depression and anxiety symptoms while controlling for numerous demographic, anthropometric, and socioeconomic confounders. Further, grip strength of females showed stronger associations with most behavioral outcomes than males. In longitudinal analysis, baseline grip strength was related to cognitive performance at ~9 years follow-up, while the reverse effect was much weaker. Further, baseline neuroticism, health, and financial satisfaction were longitudinally associated with subsequent grip strength. The results revealed widespread associations between stronger grip strength and increased grey matter volume, especially in subcortical regions and temporal cortices. Moreover, grey matter volume of these regions also correlated with better mental health and considerably mediated their relationship with grip strength.

CONCLUSIONS

Overall, using the largest population-scale neuroimaging dataset currently available, our findings provide the most well-powered characterization of interplay between grip strength, mental health, and brain structure, which may facilitate the discovery of possible interventions to mitigate cognitive decline during aging.

Five-factor model personality traits and grip strength: Meta-analysis of seven studies

OBJECTIVE

To examine the association between Five-Factor Model personality traits and grip strength.

METHOD

Adults aged 16 to 104 years old (N > 40,000) were from the Health and Retirement Study, the Midlife in the United States Study, The English Longitudinal Study of Aging, the National Health and Aging Trends Survey, the United Kingdom Household Longitudinal Study, and the Wisconsin Longitudinal Study graduate and sibling samples. Participants had data on personality traits, demographic factors, grip strength, and mediators such as depressive symptoms, physical activity, body mass index (BMI), and c-reactive protein (CRP).

RESULTS

Across all samples and a meta-analysis, higher neuroticism was related to lower grip strength (meta-analytic estimate: -0.07, 95%CI: -0.075; -0.056). Higher extraversion (0.04, 95%CI: 0.022; 0.060), openness (0.05, 95%CI: 0.032; 0.062), and conscientiousness (0.05, 95%CI: 0.04; 0.065) were associated with higher grip strength across most samples and the meta-analysis. Depressive symptoms were the most consistent mediators between neuroticism and grip strength. Depressive symptoms and physical activity partly mediated the associations with extraversion, openness, and conscientiousness. Lower CRP partly mediated the association with conscientiousness. Sex moderated the associations for extraversion, openness, and conscientiousness, with stronger associations among males. Age moderated the neuroticism association, with stronger associations among younger individuals.

CONCLUSION

This study provides replicable evidence that personality is related to grip strength and identifies potential moderators and mediators of these associations. Overall, higher neuroticism is a risk factor for low grip strength, whereas high extraversion, openness, and conscientiousness may be protective.

Relationship between handgrip strength, depression and cognitive functioning among older adults: Evidence from longitudinal ageing study in India

BACKGROUND

Handgrip strength (HGS) is a frequent and general indicator of muscle strength and it may affect several aspects of mental health among older people. This study explored the association of HGS with depression and cognitive impairment among community-dwelling older adults in resource-constrained setting of India.

METHOD

Data were drawn from the Longitudinal Ageing Study in India (LASI), and the analysis was conducted on 27,707 older adults aged 60 years and above. Outcome measures included depression (assessed by the Short Form Composite International Diagnostic Interview (CIDI-SF) and the Center for Epidemiological Studies-Depression (CES-D) scales) and cognitive impairment. Descriptive statistics and mean scores of HGS were reported and multivariable linear regression analyses were conducted to test the research hypotheses of the study.

RESULTS

Mean score of HGS was 24.33 (SD: 7.22) for males and 15.94 (SD: 5.14) for females. Mean age was 68.86 (SD: 7.19) and 68.40 (SD: 7.31) years among males and females respectively. Older participants who had weak HGS were significantly more likely to be depressed in CIDI-SF scale (B: 0.06, CI: 0.01-0.13) and CES-D scale (B: 0.02, CI: 0.01-0.03) in comparison to those who had strong HGS after adjusting for a large number of confounders. Older participants who had weak HGS were significantly more likely (B: 0.92, CI: 0.76-1.07) to have cognitive impairment compared to those who had strong HGS.

CONCLUSION

The findings highlight the independent association of HGS with major depression, depressive symptoms and cognitive impairment that have implications on promoting resistance-training programs among aged population.

Grip Strength Trajectories and Cognition in English and Chilean Older Adults: A Cross-Cohort Study

Growing evidence about the link between cognitive and physical decline suggests the early changes in physical functioning as a potential biomarker for cognitive impairment. Thus, we compared grip-strength trajectories over 12-16 years in three groups classified according to their cognitive status (two stable patterns, normal and impaired cognitive performance, and a declining pattern) in two representative UK and Chilean older adult samples. The samples consisted of 7069 UK (ELSA) and 1363 Chilean participants (ALEXANDROS). Linear Mixed models were performed. Adjustments included socio-demographics and health variables. The Declined and Impaired group had significantly lower grip-strength at baseline when compared to the Non-Impaired. In ELSA, the Declined and Impaired showed a faster decline in their grip strength compared to the Non-Impaired group but differences disappeared in the fully adjusted models. In ALEXANDROS, the differences were only found between the Declined and Non-Impaired and they were partially attenuated by covariates. Our study provides robust evidence of the association between grip strength and cognitive performance and how socio-economic factors might be key to understanding this association and their variability across countries. This has implications for future epidemiological research, as hand-grip strength measurements have the potential to be used as an indicator of cognitive performance.

Undiagnosed Dementia Is Associated with Poor Physical Function in Older Adults

BACKGROUND

Older adults with a cognitive impairment, including those not yet diagnosed, may have deficits in their physical function.

OBJECTIVE

We sought to determine the associations of cognitive impairment consistent with dementia (CICD) diagnosis status on handgrip strength, gait speed, and functional disability in older adults.

METHODS

The analytical sample included 8,383 adults aged ≥65-years without history of stroke, cancers, neurological conditions, or brain damage who participated in at least one-wave of the 2010-2016 waves of the Health and Retirement Study. A handgrip dynamometer measured handgrip strength. Men with handgrip strength <26 kg and women <16 kg were weak. Gait speed was timed across a 2.5-m course and those with slowness had gait speed <0.8 m/s. Participants with difficulty or an inability in completing any basic activities of daily living had a functional disability. The adapted Telephone Interview of Cognitive Status evaluated cognitive function. Persons with scores <7 had a CICD. Healthcare provider dementia-related diagnosis was self-reported. Undiagnosed CICD was defined as no reported dementia-related diagnosis but had CICD, while diagnosed CICD was classified as reporting a dementia-related diagnosis. Covariate-adjusted logistic models were used for the analyses.

RESULTS

Persons with undiagnosed CICD had 1.37 (95% confidence interval (CI): 1.04-1.80) greater odds for weakness and 2.02 (CI: 1.39-2.94) greater odds for slow gait speed. Older adults with diagnosed CICD had 2.29 (CI: 1.32-3.97) greater odds for slowness and 1.85 (CI: 1.19-2.90) greater odds for functional disability.

CONCLUSION

Screening for CICD could be recommended when defects in physical function are observed in older adults.

Objective measures of physical function and their association with cognitive impairment in older adults with cancer prior to treatment

INTRODUCTION

Objective measures of physical function are associated with cognitive function in community-dwelling older adults. Many older adults experience cognitive declines prior to cancer treatment initiation. Thus, it is unclear whether the association between low physical function and cognitive impairment is generalizable to older adults with cancer prior to treatment. Our objective was to examine whether objective measures of physical function were associated with cognitive impairment in geriatric oncology patients prior to treatment.

MATERIALS AND METHODS

We used prospectively collected data from an institutional database within a cancer centre and electronic medical records of older adults who had undergone a geriatric assessment before cancer treatment. Objective measures of physical function included grip strength and the Short Physical Performance Battery (SPPB). Cognitive impairment was assessed via the Mini-Cog. Multivariable logistic regression was used to determine whether grip strength and SPPB were associated with cognitive impairment prior to cancer treatment in all patients, as well as in patients with moderate-to-high comorbidity as part of a sensitivity analysis.

RESULTS

A total of 386 older adults (mean age 80.9 years) were included in the analysis. Most participants (65.3%) had low grip strength and/or low SPPB, whereas 42.2% were cognitively impaired. Neither low grip strength (odds ratio [OR] = 1.55, 95% confidence interval [CI] = 0.92-2.63, p = 0.097) nor low SPPB (OR = 1.29, 95%CI = 0.69-2.42, p = 0.41) alone or combined (OR = 1.05, 95%CI = 0.59-1.88, p = 0.85) were significantly associated with cognitive impairment in multivariable analyses of all patients. However, low SPPB was significantly associated with cognitive impairment in the sensitivity analysis restricted to patients with moderate-to-high comorbidity (OR = 4.05, 95%CI = 1.50-10.95, p = 0.006). Dependence in one or more instrumental activities of daily living [IADLs] was consistently associated with cognitive impairment in the main and sensitivity analyses.

DISCUSSION

Low physical performance and IADL dependence are associated with cognitive impairment in patients with moderate-to-high comorbidity prior to cancer treatment. Scrutiny is advised for these patients to assess for possible cognitive impairment. Larger studies are warranted to confirm our findings.

Association Between Grip Strength and Cognitive Function in US Older Adults of NHANES 2011–2014

Background: The relationship between grip strength and cognitive function remains no consensus in the older adults. Objective: To investigate the association of grip strength with cognitive function and cognitive performance in different domains. Methods: Participants of the present cross-sectional study were from the National Health and Nutrition Examination Survey 2011-2014. Grip strength was measured by grip dynamometer, and combined handgrip strength was the sum of the largest reading from each hand. Four cognitive domains (immediate and delayed memory, language, and attention) were assessed by a set of neuropsychological tests. The subjective cognitive decline was determined via self-report. Results: Among 2,618 participants, combined grip strength was positively associated with scores on global cognitive function and each cognitive domain after controlling for demographic characteristics, lifestyle factors, and history of disease. In addition, compared to those with grip strength <  46.7 kg, participants with grip strength≥75.3 kg had odds ratios of 0.36 (95% CI: 0.21 to 0.63) for poor global cognitive function, 0.66 (95% CI: 0.38 to 1.13) for poor immediate memory, 0.53 (95% CI: 0.30 to 0.93) for poor delayed memory, 0.48 (95% CI: 0.27 to 0.86) for poor language function, 0.20 (95% CI: 0.11 to 0.35) for poor attention, and 0.36 (95% CI: 0.18 to 0.73) for subjective cognitive decline in fully adjusted model. Conclusion: Older adults with higher grip strength were significantly associated with better performance on cognition function included global and various domains such as memory, language, attention, and subjective cognitive decline.

Associations Between Handgrip Strength and Dementia Risk, Cognition, and Neuroimaging Outcomes in the UK Biobank Cohort Study

IMPORTANCE

The associations between muscle strength and cognitive outcomes have sparked interest in interventions that increase muscle strength for prevention of dementia, but the associations between muscle strength and cognitive aging are unclear, particularly among middle-aged adults.

OBJECTIVE

To evaluate the association between handgrip strength (HGS) and dementia, reduced cognition, and poorer neuroimaging outcomes in a UK population of middle-aged adults.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study evaluated UK Biobank participants aged 39 to 73 years enrolled from 2006 to 2010 with measured HGS and prospectively followed up for dementia diagnosis. Data were analyzed from October 2021 to April 2022.

EXPOSURES

HGS assessed in both hands via dynamometer.

MAIN OUTCOMES AND MEASURES

Outcomes included cognitive test scores (fluid intelligence and prospective memory), brain magnetic resonance imaging measures (total brain volume, white matter hyperintensity, and hippocampal volume), and incident dementia (all-cause, vascular, and Alzheimer disease [AD] from primary care, hospital, or death records) over a median (IQR) of 11.7 (11.0-12.4) years of follow-up. Mixed-effects linear and logistic regressions and Cox proportional-hazard models were used to estimate associations, stratified by gender and adjusted for covariates. Estimates are presented per 5-kg decrement in HGS. To evaluate reverse causation, we assessed whether a polygenic risk score for AD is associated with HGS.

RESULTS

A subsample of 190 406 adult participants in the UK Biobank (mean [SD] age, 56.5 [8.1] years; 102 735 women [54%]) were evaluated. A 5-kg decrement in HGS was associated with lower fluid intelligence scores in men (β, -0.007; 95% CI, -0.010 to -0.003) and women (β, -0.04; 95% CI, -0.05 to -0.04. A 5-kg decrement in HGS was associated with worse odds of correctly responding to a prospective memory task for men (odds ratio, 0.91; 95% CI, 0.90 to 0.92) and women (odds ratio, 0.88; 95% CI, 0.87 to 0.90). A 5-kg decrement in HGS was associated with greater white matter hyperintensity volume in men (β, 92.22; 95% CI, 31.09 to 153.35) and women (β, 83.56; 95% CI, 13.54 to 153.58). A 5-kg decrement in HGS was associated with incident dementia for men (hazard ratio, 1.20; 95% CI, 1.12 to 1.28) and women (hazard ratio, 1.12; 95% CI, 1.00 to 1.26). The AD genetic risk score was not significantly associated with HGS.

CONCLUSIONS AND RELEVANCE

These findings suggest that HGS is associated with measures of neurocognitive brain health among men and women and they add to a growing body of research indicating that interventions designed to increase muscle strength, particularly among middle-aged adults, may hold promise for the maintenance of neurocognitive brain health.

Deficits in rate of force production during multifinger tasks are associated with cognitive status

OBJECTIVES

The multifinger force deficit (MFFD) is the decline in force generated by an individual finger as the number of fingers contributing to the action is increased. It has been proposed that as a measure of neural sufficiency rather than muscle status, it provides a means of detecting individuals at risk of cognitive decline. Age-related deficits in central neural drive exert a disproportionate impact on the rate at which force can be generated. We examined whether a MFFD derived from the maximum rate at which force is generated, is more sensitive to individual differences in cognitive status, than one calculated using the maximum level of force.

METHODS

Monotonic associations between each of two variants of the MFFD, and cognition (measured with the Montreal Cognitive Assessment), were estimated cross sectionally using generalized partial rank correlations, in which age, level of education and degree of handedness were included as covariates. The participants (n=26) were community dwelling adults aged 66-87.

RESULTS

The MFFD derived using the maximum rate of force development was negatively associated with cognitive status. The association for the MFFD based on the maximum level of force, was not statistically reliable. The associations with cognitive status obtained for both variants of the MFFD were of greater magnitude than those reported previously for standard grip strength dynamometry.

CONCLUSION

The sensitivity with which the MFFD detects risk of cognitive decline may be enhanced by using the maximum rate of force developed by each finger, rather than the maximum force generated by each finger.

Impact of Behavioral Assessment and Re-Test as Functional Trainings That Modify Survival, Anxiety and Functional Profile (Physical Endurance and Motor Learning) of Old Male and Female 3xTg-AD Mice and NTg Mice with Normal Aging

Longitudinal approaches for disease-monitoring in old animals face survival and frailty limitations, but also assessment and re-test bias on genotype and sex effects. The present work investigated these effects on 56 variables for behavior, functional profile, and biological status of male and female 3xTg-AD mice and NTg counterparts using two designs: (1) a longitudinal design: naïve 12-month-old mice re-tested four months later; and (2) a cross-sectional design: naïve 16-month-old mice compared to those re-tested. The results confirmed the impact as (1) improvement of survival (NTg rested females), variability of gait (3xTg-AD 16-month-old re-tested and naïve females), physical endurance (3xTg-AD re-tested females), motor learning (3xTg-AD and NTg 16-month-old re-tested females), and geotaxis (3xTg-AD naïve 16-month-old males); but (2) worse anxiety (3xTg-AD 16-month-old re-tested males), HPA axis (3xTg-AD 16-month-old re-tested and naïve females) and sarcopenia (3xTg-AD 16-month-old naïve females). Males showed more functional correlations than females. The functional profile, biological status, and their correlation are discussed as relevant elements for AD-pathology. Therefore, repetition of behavioral batteries could be considered training by itself, with some variables sensitive to genotype, sex, and re-test. In the AD-genotype, females achieved the best performance in physical endurance and motor learning, while males showed a deterioration in most studied variables.

A Link between Handgrip Strength and Executive Functioning: A Cross-Sectional Study in Older Adults with Mild Cognitive Impairment and Healthy Controls

Older adults with amnestic mild cognitive impairment (aMCI) who in addition to their memory deficits also suffer from frontal-executive dysfunctions have a higher risk of developing dementia later in their lives than older adults with aMCI without executive deficits and older adults with non-amnestic MCI (naMCI). Handgrip strength (HGS) is also correlated with the risk of cognitive decline in the elderly. Hence, the current study aimed to investigate the associations between HGS and executive functioning in individuals with aMCI, naMCI and healthy controls. Older, right-handed adults with amnestic MCI (aMCI), non-amnestic MCI (naMCI), and healthy controls (HC) conducted a handgrip strength measurement via a handheld dynamometer. Executive functions were assessed with the Trail Making Test (TMT A&B). Normalized handgrip strength (nHGS, normalized to Body Mass Index (BMI)) was calculated and its associations with executive functions (operationalized through z-scores of TMT B/A ratio) were investigated through partial correlation analyses (i.e., accounting for age, sex, and severity of depressive symptoms). A positive and low-to-moderate correlation between right nHGS (rp (22) = 0.364; p = 0.063) and left nHGS (rp (22) = 0.420; p = 0.037) and executive functioning in older adults with aMCI but not in naMCI or HC was observed. Our results suggest that higher levels of nHGS are linked to better executive functioning in aMCI but not naMCI and HC. This relationship is perhaps driven by alterations in the integrity of the hippocampal-prefrontal network occurring in older adults with aMCI. Further research is needed to provide empirical evidence for this assumption.