Handgrip Strength Predicts Longitudinal Changes in Clock Drawing Test Performance. An Observational Study in a Sample of Older Non-Demented Adults

Size or Strength? how components of muscle relate to behavioral and neuroelectric measures of executive function independent of aerobic fitness

While previous research has linked cognitive function with resistance exercise, the nuanced links between muscle strength, mass, and neuroelectric function are less understood. Therefore, this study investigated the association of muscle strength and mass with inhibitory control (IC), working memory (WM), and related neuroelectric activity. A total of 123 18-50-year-old adults completed maximal aerobic capacity and strength tests, a body composition scan, and IC and WM tasks while the N2 and P3 components of event-related potentials were recorded. Bivariate correlations revealed aerobic fitness, strength, and mass were associated with behavioral and neuroelectric outcomes. After accounting for age, sex, and aerobic fitness, strength was associated with intra-individual response time variability, accuracy, and P3 latency during WM. Muscle mass was associated with N2 latency during IC. While relationships with behavioral outcomes did not persist after controlling for the opposite muscle outcome, greater strength and mass were related to shorter P3 latency during WM and shorter N2 latency during IC, respectively. These results provide initial evidence that muscle outcomes are associated with executive function and neuroelectric processing speed, suggesting distinct contributions of strength and mass to cognition. This work highlights the significance of maintaining muscle strength and mass alongside aerobic fitness for optimal cognitive health.

The contribution of motor efficiency to drawing performance of older people with and without signs of cognitive decline

In clinical practice, different drawing tests are used for the assessment of cognitive efficiency in the geriatric population. However, so far, the contribution of motor skills to drawing performance has not been sufficiently examined in the late adult life span. This study was aimed at disentangling the role played by motor functioning in three well-known drawing tests that in the clinical field are commonly used to detect some signs of cognitive impairment of older individuals. One hundred and forty-nine community dwellers (M_age = 77.4 years, SD = 5.9 years) completed a battery of tests assessing global cognitive efficiency, drawing skills (i.e., Clock Drawing, Visuo-spatial Drawing ACE-R, Copy Figures Tests), handgrip muscular strength (HGS), and functional mobility (assessed through the Timed-Up-and-Go test). Significant relationships were found among those measures. Moreover, handgrip strength and functional mobility explained 12-19% of the variance in each drawing condition. Finally, participants exhibiting poorer HGS performed worse the drawing tasks and were successively recognized as cognitively deteriorated. In conclusion, these findings highlight that motor skills can significantly impact the assessment of cognitive efficiency in late adulthood. Therefore, in clinical practice, the concurrent assessment of basic motor functions (in terms of muscular strength and functional mobility) and cognitive efficiency of the geriatric population at risk for cognitive decline should be encouraged.

Handgrip strength is associated with learning and verbal fluency in older men without dementia: insights from the NHANES

Low handgrip strength, a hallmark measure of whole-body strength, has been linked with greater odds of cognitive decline and dementia; however, conflicting findings, which could be due to population characteristics and choice of tools, such for the assessment of handgrip strength and cognitive function domains, also exist. Therefore, we examined the relationship of handgrip strength with a comprehensive list of tests to assess domains of cognitive function using a representative sample of US older men and women without neurodegenerative disorders such as dementia. We analyzed cross-sectional data from the US National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014, with a study cohort of 777 older adults (380 men and 397 women) above 60 years of age. Handgrip strength was assessed using a handgrip dynamometer, while cognitive function was assessed through the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test (WLLT), Word List Recall Test (WLRT), Intrusion Word Count Test (WLLT-IC and WLRT-IC), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). Sex-stratified multiple linear regression analyses were performed upon covariate adjustment for age, ethnicity, socio-economic status, education, medical history, body mass index, physical activity, energy, protein, and alcohol intake. Maximal handgrip strength was positively associated with cognitive function scores, including CERAD WLLT (P = 0.009, R² = 0.146) and AFT (P = 0.022, R² = 0.024) in older men, but not in women (CERAD WLLT: P = 0.253, AFT: P = 0.370). No significant associations with CERAD WLLRT (men: P = 0.057, women: P = 0.976), WLLT-IC (men: P = 0.671, women: P = 0.869), WLLRT-IC (men: P = 0.111, women: P = 0.861), and DSST (men: P = 0.108, women: P = 0.091) were observed. Dose-response curves exhibited a prominent linear relationship between all significant associations after covariate adjustment, with no indication of a plateau in these relationships. In conclusion, higher handgrip strength was independently associated with better learning ability for novel verbal information and verbal fluency in US men over the age of 60 and without dementia. Longitudinal studies are required to confirm whether muscle strength independently predicts cognitive function changes in older adults in a sex-specific manner, and whether this connection is affirmed to the possibility of reverse causation due to declines in physical activity levels in the preclinical phase of dementia.

The relationship between clinical measures of cognitive function and grip strength in healthy older adults

BACKGROUND

Handgrip strength is considered a surrogate for musculoskeletal strength, however there is emerging evidence of an association with cognition. The specific neurocognitive attribute which best associates with grip strength is unknown.

METHODS

We performed a secondary analysis on baseline data in 49 healthy older adults. Grip strength was corrected for body mass index. Control independent variables included age, Montreal Cognitive Assessment, and Trails B. Experimental variables included a clinical measure of simple reaction time, and clinical and computerized go/no-go tasks. The clinical Go/No-Go measure was determined with ReacStick, a rod-shaped device which - when released by the examiner - requires the participant to decide within 390 ms whether to catch the device or let it fall to the ground.

RESULTS

Bivariate analysis demonstrated that age and all cognitive measures other than the computer go/no-go response accuracy related to grip strength. Multivariate analyses showed that following inclusion of the control variables, only ReacStick measures (reaction accuracy/simple reaction time) significantly predicted grip strength, explaining an additional 15.90% variance (p = 0.026). In contrast, computerized Go/No-Go accuracy (p = 0.391), response time variability (p = 0.463), and the control variables (p value range = 0.566-0.942) did not predict grip strength.

CONCLUSION

A short latency (< 390 ms) visuomotor Go/No-Go task independently predicted over 15% of grip strength variance, whereas a slower screen-based Go/No-Go task did not. These findings support the notion that declining grip strength likely reflects sub-clinical brain changes as well as musculoskeletal dysfunction, possibly explaining the potent relationships between grip strength, disability, chronic disease, and mortality.

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.

Abnormal Static and Dynamic Functional Network Connectivity in Patients With Presbycusis

Aim: This study aimed to investigate abnormal static and dynamic functional network connectivity (FNC) and its association with cognitive function in patients with presbycusis.

Methods: In total, 60 patients with presbycusis and 60 age-, sex-, and education-matched healthy controls (HCs) underwent resting-state functional MRI (rs-fMRI) and cognitive assessments. Group independent component analysis (ICA) was carried out on the rs-fMRI data, and eight resting-state networks (RSNs) were identified. Static and dynamic FNCs (sFNC and dFNC) were then constructed to evaluate differences in RSN connectivity between the patients with presbycusis and the HCs. Furthermore, the correlations between these differences and cognitive scores were analyzed.

Results: Patients with presbycusis had differences in sFNC compared with HCs, mainly reflected in decreased sFNC in the default mode network (DMN)-left frontoparietal network (LFPN) and attention network (AN)-cerebellum network (CN) pairs, but they had increased sFNC in the auditory network (AUN) between DMN domains. The decreased sFNC in the DMN-LFPN pair was negatively correlated with their TMT-B score (r = –0.441, p = 0.002). Patients with presbycusis exhibited aberrant dFNCs in State 2 and decreased dFNCs between the CN and AN and the visual network (VN). Moreover, the presbycusis group had a shorter mean dwell time (MDT) and fraction time (FT) in State 3 (p = 0.0027; p = 0.0031, respectively).

Conclusion: This study highlighted differences in static and dynamic functional connectivity in patients with presbycusis and suggested that FNC may serve as an important biomarker of cognitive performance since abnormal alterations can better track cognitive impairment in presbycusis.

Cognitive Dispersion Predicts Grip Strength Trajectories in Men but not Women in a Sample of the Oldest Old Without Dementia

Background and Objectives

Grip strength is a reliable marker of biological vitality and it typically demonstrates an expected decline in older adults. According to the common-cause hypothesis, there is also a significant association between cognitive and physical function in older adults. Some specific cognitive functions have been shown to be associated with grip strength trajectories with most research solely focused on cutoff points or mean cognitive performance. In the present study, we examine whether a measure of cognitive dispersion might be more informative. We therefore used an index that quantifies dispersion in cognitive scores across multiple cognitive tests, shown to be associated with detrimental outcomes in older adults.

Research Design and Methods

Using repeated grip strength measures from men and women aged 80 and older, free of dementia in the OCTO-Twin study, we estimated aging-related grip strength trajectories. We examined the association of cognitive dispersion and mean cognitive function with grip strength level and aging-related rate of change, accounting for known risk factors.

Results

Cognitive dispersion was associated with grip strength trajectories in men and the association varied by mean cognitive performance, whereas we found no association in women.

Discussion and Implications

Our results provide evidence of a sex-specific vitality association between cognitive dispersion and aging-related trajectories of grip strength. Our results support the call for integration of sex and gender in health promotion and intervention research.

A Multimodal Risk Network Predicts Executive Function Trajectories in Non-demented Aging

Background: Multiple modalities of Alzheimer's disease (AD) risk factors may operate through interacting networks to predict differential cognitive trajectories in asymptomatic aging. We test such a network in a series of three analytic steps. First, we test independent associations between three risk scores (functional-health, lifestyle-reserve, and a combined multimodal risk score) and cognitive [executive function (EF)] trajectories. Second, we test whether all three associations are moderated by the most penetrant AD genetic risk [Apolipoprotein E (APOE) ε4+ allele]. Third, we test whether a non-APOE AD genetic risk score further moderates these APOE × multimodal risk score associations. Methods: We assembled a longitudinal data set (spanning a 40-year band of aging, 53-95 years) with non-demented older adults (baseline n = 602; Mage = 70.63(8.70) years; 66% female) from the Victoria Longitudinal Study (VLS). The measures included for each modifiable risk score were: (1) functional-health [pulse pressure (PP), grip strength, and body mass index], (2) lifestyle-reserve (physical, social, cognitive-integrative, cognitive-novel activities, and education), and (3) the combination of functional-health and lifestyle-reserve risk scores. Two AD genetic risk markers included (1) APOE and (2) a combined AD-genetic risk score (AD-GRS) comprised of three single nucleotide polymorphisms (SNPs; Clusterin[rs11136000], Complement receptor 1[rs6656401], Phosphatidylinositol binding clathrin assembly protein[rs3851179]). The analytics included confirmatory factor analysis (CFA), longitudinal invariance testing, and latent growth curve modeling. Structural path analyses were deployed to test and compare prediction models for EF performance and change. Results: First, separate analyses showed that higher functional-health risk scores, lifestyle-reserve risk scores, and the combined score, predicted poorer EF performance and steeper decline. Second, APOE and AD-GRS moderated the association between functional-health risk score and the combined risk score, on EF performance and change. Specifically, only older adults in the APOEε4- group showed steeper EF decline with high risk scores on both functional-health and combined risk score. Both associations were further magnified for adults with high AD-GRS. Conclusion: The present multimodal AD risk network approach incorporated both modifiable and genetic risk scores to predict EF trajectories. The results add an additional degree of precision to risk profile calculations for asymptomatic aging populations.

Effectiveness of Continuous Grip Strength Measurement Using Social Assistive Robots on Older Adults at Home

In this study, the effect of social assistive robots (SARs) on the continuity of health management activities was verified through the measurement of daily grip strength. We proposed and developed an intervention system for grip strength measurement and installed it in a SAR. Then, 23 older adults used the system at home with and without a SAR. Each setup was applied for three weeks and the rates at which the participants forgot their daily grip strength measurements were compared at the end of the period. The rates at which the daily measurements were forgotten decreased significantly when a SAR was used. In particular, 9 participants were able to decrease their rate of forgotten measurements after they used a SAR. Thus, the SAR enabled the participants to regularly perform grip strength measurement activities. These findings indicate that appropriate intervention measures using SARs are effective in promoting the continuity of daily healthcare activities of older adults living at home.

A Coordinated Multi-study Analysis of the Longitudinal Association Between Handgrip Strength and Cognitive Function in Older Adults

OBJECTIVE

Handgrip strength, an indicator of overall muscle strength, has been found to be associated with slower rate of cognitive decline and decreased risk for cognitive impairment and dementia. However, evaluating the replicability of associations between aging-related changes in physical and cognitive functioning is challenging due to differences in study designs and analytical models. A multiple-study coordinated analysis approach was used to generate new longitudinal results based on comparable construct-level measurements and identical statistical models and to facilitate replication and research synthesis.

METHODS

We performed coordinated analysis on 9 cohort studies affiliated with the Integrative Analysis of Longitudinal Studies of Aging and Dementia (IALSA) research network. Bivariate linear mixed models were used to examine associations among individual differences in baseline level, rate of change, and occasion-specific variation across grip strength and indicators of cognitive function, including mental status, processing speed, attention and working memory, perceptual reasoning, verbal ability, and learning and memory. Results were summarized using meta-analysis.

RESULTS

After adjustment for covariates, we found an overall moderate association between change in grip strength and change in each cognitive domain for both males and females: Average correlation coefficient was 0.55 (95% CI = 0.44-0.56). We also found a high level of heterogeneity in this association across studies.

DISCUSSION

Meta-analytic results from nine longitudinal studies showed consistently positive associations between linear rates of change in grip strength and changes in cognitive functioning. Future work will benefit from the examination of individual patterns of change to understand the heterogeneity in rates of aging and health-related changes across physical and cognitive biomarkers.

The Beneficial Effects of Cognitive Walking Program on Improving Cognitive Function and Physical Fitness in Older Adults

Exercise and cognitive training can improve the brain-related health of the elderly. We investigated the effects of a cognitive walking program (CWP) involving simultaneous performance of indoor walking and cognitive training on cognitive function and physical fitness compared to normal walking (NW) outdoors. Participants were grouped according to whether they performed regular exercise for at least 3 months prior to the participation in this study. Active participants were assigned to the CWP-active group (CWPAG). Sedentary participants were randomly assigned to the CWP (CWPSG) or NW group (NWSG). CWP and NW were performed for 60 min, 3 times a week, for 6 months. Cognitive function (attention, visuospatial function, memory, and frontal/executive function) and physical fitness (cardiorespiratory fitness, lower extremity muscular strength, and active balance ability) were measured at baseline, 3 months, and 6 months after the program onset. Cognitive function showed improvements over time in all three groups, especially in CWPAG. No clear difference was observed between CWPSG and NWSG. Improvements in all fitness measures were also observed in all three groups. These findings collectively indicate the beneficial effects of CWP, as well as NW, on improving cognitive function and physical fitness in older adults, especially those who are physically active.

Cortical hemodynamics as a function of handgrip strength and cognitive performance: a cross-sectional fNIRS study in younger adults

BACKGROUND

There is growing evidence for a positive correlation between measures of muscular strength and cognitive abilities. However, the neurophysiological correlates of this relationship are not well understood so far. The aim of this study was to investigate cortical hemodynamics [i.e., changes in concentrations of oxygenated (oxyHb) and deoxygenated hemoglobin (deoxyHb)] as a possible link between measures of muscular strength and cognitive performance.

METHODS

In a cohort of younger adults (n = 39, 18-30 years), we assessed (i) handgrip strength by a handhold dynamometer, (ii) short-term working memory performance by using error rates and reaction times in the Sternberg task, and (iii) cortical hemodynamics of the prefrontal cortex (PFC) via functional near-infrared spectroscopy (fNIRS).

RESULTS

We observed low to moderate negative correlations (rp =  ~ - 0.38 to - 0.51; p < 0.05) between reaction time and levels of oxyHb in specific parts of the PFC. Furthermore, we noticed low to moderate positive correlations (rp =  ~ 0.34 to 0.45; p < 0.05) between reaction times and levels of deoxyHb in distinct parts of the PFC. Additionally, higher levels of oxyHb (rp (35) = 0.401; p = 0.014) and lower levels of deoxyHb (rp (34) = - 0.338; p = 0.043) in specific parts of the PFC were linked to higher percentage of correct answers. We also found low to moderate correlations (p < 0.05) between measures of handgrip strength and levels of oxyHb (rp =  ~ 0.35; p < 0.05) and levels of deoxyHb (rp =  ~ - 0.25 to - 0.49; p < 0.05) in specific parts of the PFC. However, there was neither a correlation between cognitive performance and handgrip strength nor did cortical hemodynamics in the PFC mediate the relationship between handgrip strength and cognitive performance (p > 0.05).

CONCLUSION

The present study provides evidence for a positive neurobehavioral relationship between cortical hemodynamics and cognitive performance. Our findings further imply that in younger adults higher levels of handgrip strength positively influence cortical hemodynamics although the latter did not necessarily culminate in better cognitive performance. Future research should examine whether the present findings can be generalized to other cohorts (e.g., older adults).

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

Purpose: Loss of grip strength and cognitive impairment are prevalent in the elderly, and they may share the pathogenesis in common. Several original studies have investigated the association between them, but the results remained controversial. In this systematic review and meta-analysis, we aimed to quantitatively determine the relationship between baseline grip strength and the risk of cognitive impairment and provide evidence for clinical work.

Methods: We performed a systematic review using PubMed, EMBASE, Cochrane, and Web of Science up to March 23, 2020, and focused on the association between baseline grip strength and onset of cognitive impairment. Next, we conducted a meta-analysis using a hazard ratio (HR) and 95% confidence interval (CI) as effect measures. Heterogeneity between the studies was examined using I² and p-value. Sensitivity analyses and subgroup analyses were also performed, and publication bias was assessed by Begg's and Egger's tests.

Results: Fifteen studies were included in this systematic review. After sensitivity analyses, poorer grip strength was associated with more risk of cognitive decline and dementia (HR = 1.99, 95%CI: 1.71–2.32; HR = 1.54, 95%CI: 1.32–1.79, respectively). Furthermore, subgroup analysis indicated that people with poorer strength had more risk of Alzheimer's disease (AD) and non-AD dementia (HR = 1.41, 95%CI: 1.09–1.81; HR = 1.45, 95%CI: 1.10–1.91, respectively).

Conclusions: Lower grip strength is associated with more risk of onset of cognitive decline and dementia despite of subtype of dementia. We should be alert for the individuals with poor grip strength and identify cognitive dysfunction early.

Disrupted Functional Network Connectivity Predicts Cognitive Impairment in Presbycusis Patients

Purpose: Individuals with presbycusis often show deficits in cognitive function, however, the exact neurophysiological mechanisms are not well understood. This study explored the alterations in intra- and inter-network functional connectivity (FC) of multiple networks in presbycusis patients, and further correlated FC with cognitive assessment scores to assess their ability to predict cognitive impairment.

Methods: Resting-state functional magnetic resonance imaging (rs-fMRI) was performed in 40 presbycusis patients and 40 matched controls, and 12 resting-state networks (RSNs) were identified by independent component analysis (ICA) approach. A two-sample t-test was carried out to detect the intra-network FC differences, and functional network connectivity (FNC) was calculated to compare the inter-network FC differences. Pearson or Spearman correlation analysis was subsequently used to explore the correlation between altered FC and cognitive assessment scores.

Results: Our study demonstrated that patients with presbycusis showed significantly decreased FC in the subcortical limbic network (scLN), default mode network (DMN), executive control network (ECN), and attention network (AN) compared with the control group. Moreover, the connectivity for scLN-AUN (auditory network) and VN (visual network)-DMN were found significantly increased while AN-DMN was found significantly decreased in presbycusis patients. Ultimately, this study revealed the intra- and inter-network alterations associated with some cognitive assessment scores.

Conclusion: This study observed intra- and inter-network FC alterations in presbycusis patients, and investigated that presbycusis can lead to abnormal connectivity of RSNs and plasticity compensation mechanism, which may be the basis of cognitive impairment, suggesting that FNC can be used to predict potential cognitive impairment in their early stage.

Understated Cognitive Impairment Assessed with the Clock-Drawing Test in Community-Dwelling Individuals Aged ≥50 Years

OBJECTIVES

To estimate the prevalence of understated cognitive impairment by administering the Clock-Drawing Test (CDT) to community-dwelling individuals aged ≥50 years and to investigate the associated clinical phenotype.

DESIGN

A cross-sectional analysis of baseline data on community-dwelling individuals assessed at an outpatient clinic in the Paris region of France.

SETTING AND PARTICIPANTS

Participants aged ≥50 years (n = 488, median age: 62.1 years) prospectively included in the SUCCessful agEing outpatiEnt's Department survey between 2010 and 2014.

METHODS

A multidimensional geriatric assessment, including cognition [7-point CDT, Mini-Mental State Examination (MMSE), the 5-word screening test (5-WT), and the Frontal Assessment Battery (FAB)], gait speed in dual tasks, mood [the Geriatric Depression Scale (GDS)], balance, physical functions (gait speed and handgrip strength), nutrition, bone density, and comorbidities; major cardiovascular risk factors, and Scheltens and Fazekas scores on brain magnetic resonance imaging. Baseline characteristics were analyzed as a function of the CDT score (<7 vs 7), using age-adjusted logistic models.

RESULTS

The prevalence of impairment in the CDT was 23.6%; higher than the values for the MMSE (12.7%), 5-WT (2.3%), and FAB (16.6%). In age-adjusted analyses, a lower educational level (odds ratio [95% confidence interval] = 0.72 [0.58‒0.89]), diabetes (2.57 [1.14‒5.79]), metabolic syndrome (1.93 [1.05‒3.56]), lower gait speed in the cognitive dual task (1.27 [1.05‒1.53]), a poorer Geriatric Depression Scale score (1.86 [1.04‒3.32]), a poorer MMSE score (2.56 [1.35‒4.88]), a poorer FAB score (1.79 [1.01‒3.16]), impaired episodic memory in the 5-WT (4.11 [1.12‒15.02]), and a higher Scheltens score (P = .001) were significantly associated with CDT impairment.

CONCLUSIONS AND IMPLICATIONS

Understated cognitive impairment is common among young seniors and is associated with factors known to be linked to a higher risk of cognitive decline and dementia. These findings suggest that the CDT may be of value for identifying high-risk individuals who may then benefit from targeted multidomain prevention actions (diet, exercise, cognitive training, and vascular risk factor management).

Grip Strength: An Indispensable Biomarker For Older Adults

Grip strength has been proposed as a biomarker. Supporting this proposition, evidence is provided herein that shows grip strength is largely consistent as an explanator of concurrent overall strength, upper limb function, bone mineral density, fractures, falls, malnutrition, cognitive impairment, depression, sleep problems, diabetes, multimorbidity, and quality of life. Evidence is also provided for a predictive link between grip strength and all-cause and disease-specific mortality, future function, bone mineral density, fractures, cognition and depression, and problems associated with hospitalization. Consequently, the routine use of grip strength can be recommended as a stand-alone measurement or as a component of a small battery of measurements for identifying older adults at risk of poor health status.

Sarcopenia and Psychosocial Variables in Patients in Intensive Care Units: The Role of Nutrition and Rehabilitation in Prevention and Treatment

Critical illness leads to decline in muscle mass that promotes decline in physical function and psychological function and may lead to cognitive decline or dementia. Nurses are key to driving the multidisciplinary interventions that prevent protein loss and promote positive outcomes for critically ill patients.

Associations between handgrip strength and mild cognitive impairment in middle-aged and older adults in six low- and middle-income countries

OBJECTIVES

A number of small-scale, single-country studies have suggested that muscular weakness may be a biomarker for cognitive health, mild cognitive impairment (MCI), and dementia. However, multinational, representative studies are lacking, particularly from low- and middle-income countries (LMICs). Thus, we assessed the association between muscular strength (measured by maximal handgrip) and MCI in six LMICs (China, Ghana, India, Mexico, Russia, and South Africa), using nationally representative data.

METHODS

Cross-sectional, community-based data on individuals aged 50 years or older from the World Health Organization's Study on Global Ageing and Adult Health were analyzed. MCI was defined according to the National Institute on Aging-Alzheimer's Association criteria. Weak handgrip strength was defined as less than 30 kg for men and less than 20 kg for women using the average value of two handgrip measurements of the dominant hand. Multivariable logistic regression analysis was conducted to assess the association between muscular strength and MCI.

RESULTS

A total of 32 715 participants were included (mean age 62 ± SD 15.6 y and 51.7% female). The prevalence of MCI and weak handgrip strength was 15.3% (95% CI, 14.4%-16.3%) and 46.5% (95% CI, 43.6%-49.5%), respectively. After adjustment for potential confounders, weak handgrip strength was associated with 1.41 (95% CI, 1.23-1.61) times higher odds for MCI. The corresponding figures for those aged 50 to 64 years and 65 years or older were 1.35 (95% CI, 1.14-1.60) and 1.54 (95% CI, 1.27-1.86), respectively.

CONCLUSIONS

Muscular weakness may provide a clinically useful indicator of MCI risk. Increasing our understanding of the connection between muscular and cognitive function could ultimately lead to the development and broader implementation of resistance training interventions targeting both physical and cognitive health.

Clock drawing and neuroanatomical correlates: A systematic review

OBJECTIVE

The popular clock drawing test (CDT) is easy to administer, acceptable to patients, and has excellent psychometric properties. Although it has been used primarily as a cognitive screening test, many studies have attempted to establish the CDT's ability to localize specific brain lesions or pathology. This systematic review aimed to summarize the evidence on the neuroanatomical correlates of the CDT.

METHODS

Using PRISMA guidelines, the authors systematically reviewed the evidence on neuroanatomical correlates of clock drawing by a systematic search in six databases (Pubmed, CINHL, PsychINFO, HealthStar, Embase, and Web of Science) until January 2018. Studies were included if they reported CDT correlations with anatomical brain lesions documented by neuroimaging.

RESULTS

Forty-five papers met inclusion criteria. Thirty-one studies identified distinct areas of neuroanatomical correlates of CDT utilizing different scoring methods and imaging techniques. Nine articles reported on the degree of white matter hyperintensities that correlated with lower scores on CDT and the severity of cognitive deficits. Five articles focused on postacute cerebrovascular accidents correlated with CDT performance. A variety of different anatomical lesions, located in all areas of the brain, were associated with abnormalities on the CDT.

CONCLUSIONS

The CDT, regardless of scoring method and population studied, was not associated with any consistent, specific brain localization. This systematic review supports the use of the CDT as a cognitive screening test rather than a method of localizing brain lesions.

Coming to grips with economic development: Variation in adult hand grip strength during health transition in Vanuatu

OBJECTIVES

To determine whether (1) maximal handgrip strength (HGS) is associated with inter-island level of economic development in Vanuatu, (2) how associations between island of residence and HGS are mediated by age, sex, body size/composition, and individual sociodeomographic variation, and (3) whether HGS is predictive of hypertension.

MATERIAL AND METHODS

HGS was collected from 833 adult (aged 18 and older) men and women on five islands representing a continuum of economic development in Vanuatu. HGS was measured using a handheld dynamometer. Participants were administered in an extensive sociobehavioral questionnaire and were also assessed for height, weight, percent body fat, forearm skinfold thickness, forearm circumference, and blood pressure.

RESULTS

HGS was significantly greater in men than in women regardless of island of residence. HGS was also significantly positively associated with inter-island level of economic development. Grip strength-to-weight ratio was not different across islands except in older individuals, where age-related decline occurred primarily on islands with greater economic development. HGS significantly declined with age in both men and women.

CONCLUSION

HGS is positively associated with modernization in Vanuatu, but the relationship between HGS and modernization is largely due to an association of both variables with increased body size on more modernized islands. Further research on the role of individual variation in diet and physical activity are necessary to clarify the relationship between HGS and modernization.

Association Between Muscular Strength and Cognition in People With Major Depression or Bipolar Disorder and Healthy Controls

IMPORTANCE

Objective physical fitness measures, such as handgrip strength, are associated with physical, mental, and cognitive outcomes in the general population. Although people with mental illness experience reduced physical fitness and cognitive impairment, the association between muscular strength and cognition has not been examined to date.

OBJECTIVE

To determine associations between maximal handgrip strength and cognitive performance in people with major depression or bipolar disorder and in healthy controls.

DESIGN, SETTING, AND PARTICIPANTS

In a multicenter, population-based study conducted between February 13, 2005, and October 1, 2010, in the United Kingdom, cross-sectional analysis was conducted of baseline data from 110 067 participants in the UK Biobank. Data analysis was performed between August 3 and August 18, 2017. Invitations were mailed to approximately 9.2 million UK homes, recruiting 502 664 adults, all aged 37 to 73 years. Clinically validated measures were used to identify individuals with major recurrent depression (moderate or severe) or bipolar disorder (type I or type II) and healthy controls (those with no indication of present or previous mood disorders).

MAIN OUTCOMES AND MEASURES

Handgrip dynamometry was used to measure muscular function. Cognitive functioning was assessed using computerized tasks of reaction time, visual memory, number memory, reasoning, and prospective memory. Generalized linear mixed models assessed the association between handgrip strength and cognitive performance, controlling for age, educational level, sex, body weight, and geographic region.

RESULTS

Of the 110 067 participants, analyses included 22 699 individuals with major depression (mean [95% range] age, 55.5 [41-68] years; 7936 [35.0%] men), 1475 with bipolar disorder (age, 54.4 [41-68] years; 748 [50.7%] men), and 85 893 healthy controls (age, 53.7 [41-69] years; 43 000 [50.0%] men). In those with major depression, significant positive associations (P < .001) between maximal handgrip strength and improved performance on all 5 cognitive tasks were found, including visual memory (coefficient, -0.146; SE, 0.014), reaction time (coefficient, -0.036; SE, 0.002), reasoning (coefficient, 0.213; SE, 0.02), number memory (coefficient, 0.160; SE, 0.023), and prospective memory (coefficient, 0.341; SE, 0.024). Similar results were found in healthy controls. Among participants with bipolar disorder, handgrip strength was positively associated with improved visual memory (coefficient, -0.129; SE, 0.052; P = .01), reaction time (coefficient, -0.047; SE, 0.007; P < .001), prospective memory (coefficient, 0.262; SE, 0.088; P = .003), and reasoning (coefficient, 0.354; SE, 0.08; P < .001).

CONCLUSIONS AND RELEVANCE

Grip strength may provide a useful indicator of cognitive impairment in people with major depression and bipolar disorder. Future research should investigate causality, assess the functional implications of handgrip strength in psychiatric populations, and examine how interventions to improve muscular fitness affect neurocognitive status and socio-occupational functioning.

Grip Strength Is Associated With Cognitive Performance in Schizophrenia and the General Population: A UK Biobank Study of 476559 Participants

Background

Handgrip strength may provide an easily-administered marker of cognitive functional status. However, further population-scale research examining relationships between grip strength and cognitive performance across multiple domains is needed. Additionally, relationships between grip strength and cognitive functioning in people with schizophrenia, who frequently experience cognitive deficits, has yet to be explored.

Methods

Baseline data from the UK Biobank (2007-2010) was analyzed; including 475397 individuals from the general population, and 1162 individuals with schizophrenia. Linear mixed models and generalized linear mixed models were used to assess the relationship between grip strength and 5 cognitive domains (visual memory, reaction time, reasoning, prospective memory, and number memory), controlling for age, gender, bodyweight, education, and geographical region.

Results

In the general population, maximal grip strength was positively and significantly related to visual memory (coefficient [coeff] = -0.1601, standard error [SE] = 0.003), reaction time (coeff = -0.0346, SE = 0.0004), reasoning (coeff = 0.2304, SE = 0.0079), number memory (coeff = 0.1616, SE = 0.0092), and prospective memory (coeff = 0.3486, SE = 0.0092: all P < .001). In the schizophrenia sample, grip strength was strongly related to visual memory (coeff = -0.155, SE = 0.042, P < .001) and reaction time (coeff = -0.049, SE = 0.009, P < .001), while prospective memory approached statistical significance (coeff = 0.233, SE = 0.132, P = .078), and no statistically significant association was found with number memory and reasoning (P > .1).

Conclusions

Grip strength is significantly associated with cognitive functioning in the general population and individuals with schizophrenia, particularly for working memory and processing speed. Future research should establish directionality, examine if grip strength also predicts functional and physical health outcomes in schizophrenia, and determine whether interventions which improve muscular strength impact on cognitive and real-world functioning.