Get a grip: individual variations in grip strength are a marker of brain health

Biomarkers of aging: from molecules and surrogates to physiology and function

Many countries face an unprecedented challenge in aging demographics. This has led to an exponential growth in research on aging, which, coupled to a massive financial influx of funding in the private and public sectors, has resulted in seminal insights into the underpinnings of this biological process. However, critical validation in humans has been hampered by the limited translatability of results obtained in model organisms, additionally confined by the need for extremely time-consuming clinical studies in the ostensible absence of robust biomarkers that would allow monitoring in shorter time frames. In the future, molecular parameters might hold great promise in this regard. In contrast, biomarkers centered on function, resilience, and frailty are available at the present time, with proven predictive value for morbidity and mortality. In this review, the current knowledge of molecular and physiological aspects of human aging, potential antiaging strategies, and the basis, evidence, and potential application of physiological biomarkers in human aging are discussed.

Cumulative handgrip strength and longitudinal changes in cognitive function and daily functioning among people aged 50 years and older: evidence from two longitudinal cohort studies

BACKGROUND AND PURPOSE

Our study assesses the association between cumulative handgrip strength and longitudinal changes in cognitive function and daily functioning.

METHODS

Two comparative cohort studies were used, including the English Longitudinal Study of Ageing (ELSA) and the Survey of Health, Ageing and Retirement in Europe (SHARE). Cumulative handgrip strength was calculated using three repeated measurements of handgrip strength. Linear mixed regression models evaluated the association between cumulative handgrip strength and longitudinal changes in cognitive function and daily functioning. Cox regression models were performed to determine the association between cumulative handgrip strength and the risk of cognitive and functional impairment.

RESULTS

Individuals with lower levels of cumulative handgrip strength had lower global cognition (β: -0.244; 95% CI: -0.317, -0.170 for ELSA and -0.359; -0.406, -0.311 for SHARE) and experienced a faster decline in cognitive function over time (-0.025; -0.037, -0.013 for ELSA, and -0.019; -0.026, -0.013 in SHARE). We found lower levels of cumulative handgrip strength were associated with lower daily functioning (β: 0.267; 95% CI: 0.161, 0.374 for ELSA and 0.153; 0.079, 0.227 for SHARE), and a faster decline in daily functioning over time (0.105; 0.081, 0.129 for ELSA and 0.217; 0.195, 0.238 for SHARE). Furthermore, lower levels of cumulative handgrip strength were related to a higher risk of cognitive and functional impairment.

CONCLUSIONS

Our study suggested that lower levels of cumulative handgrip strength was related to an accelerated decline in cognitive function and daily functioning. Persistently strengthening muscle strength should be emphasized in preventing neurodegenerative disorders and disabilities.

Do Transformers and CNNs Learn Different Concepts of Brain Age?

"Predicted brain age" refers to a biomarker of structural brain health derived from machine learning analysis of T1-weighted brain magnetic resonance (MR) images. A range of machine learning methods have been used to predict brain age, with convolutional neural networks (CNNs) currently yielding state-of-the-art accuracies. Recent advances in deep learning have introduced transformers, which are conceptually distinct from CNNs, and appear to set new benchmarks in various domains of computer vision. Given that transformers are not yet established in brain age prediction, we present three key contributions to this field: First, we examine whether transformers outperform CNNs in predicting brain age. Second, we identify that different deep learning model architectures potentially capture different (sub-)sets of brain aging effects, reflecting divergent "concepts of brain age". Third, we analyze whether such differences manifest in practice. To investigate these questions, we adapted a Simple Vision Transformer (sViT) and a shifted window transformer (SwinT) to predict brain age, and compared both models with a ResNet50 on 46,381 T1-weighted structural MR images from the UK Biobank. We found that SwinT and ResNet performed on par, though SwinT is likely to surpass ResNet in prediction accuracy with additional training data. Furthermore, to assess whether sViT, SwinT, and ResNet capture different concepts of brain age, we systematically analyzed variations in their predictions and clinical utility for indicating deviations in neurological and psychiatric disorders. Reassuringly, we observed no substantial differences in the structure of brain age predictions across the model architectures. Our findings suggest that the choice of deep learning model architecture does not appear to have a confounding effect on brain age studies.

Knee Extensor Structure and Function in Children, Adolescents, Adults, and Older Adults With Obesity: A Systematic Review and Meta-Analysis

OBJECTIVE

This study aims to evaluate the association between obesity and both absolute and relative measures of knee extensor muscle structure and contractile function across different age groups, including children, adolescents, adults, and older adults.

METHODS

A search for potential studies was performed in four electronic databases. Data were meta-analyzed using a random-effects model for our primary outcomes of knee extensor structure (muscle size and quality) and function (maximal force/torque, rapid torque, and fatigue) and compared between those with or without obesity in each age group.

RESULTS

The findings indicate that obesity significantly increases absolute measures of knee extensor maximal contractile function and muscle size. However, obesity was associated with a decrease in relative measures of maximal and rapid contractile function and muscle quality. The association of obesity with these muscle characteristics varied by age group, with the effects on knee extensor structure and function diminishing with age.

CONCLUSIONS

This systematic review and meta-analysis demonstrate that while obesity enhances absolute knee extensor muscle size and maximal force/torque, it detrimentally affects relative muscle function and quality, particularly related to activities of daily living. These effects are less pronounced in older adults, suggesting that age modulates the impact of obesity on muscle structure and function. The findings underscore the importance of interventions targeting the improvement of relative muscle function and quality in individuals with obesity. Further research is necessary to better understand these relationships and to develop more effective intervention strategies for obesity.

REGISTRATION

This protocol was prospectively registered in the Open Science Framework (DOI: 10.17605/OSF.IO/ZGUK6).

Blood biomarkers of Alzheimer's disease and 12-year muscle strength trajectories in community-dwelling older adults: a cohort study

BACKGROUND

Age-related muscle function decline is a major impediment to healthy ageing. We aimed to investigate the association between a panel of Alzheimer's disease-related biomarkers and longitudinal trajectories of muscle strength, while exploring the influence of cognitive function.

METHODS

In this cohort study, we gathered data from the Swedish National study on Aging and Care in Kungsholmen (SNAC-K), an ongoing prospective study that includes adults aged 60 years and older, from central Stockholm, Sweden. We included data from baseline to the fourth follow-up (March 21, 2001, to Dec 31, 2016). Seven Alzheimer's disease-related blood biomarkers were measured in dementia-free, community dwelling participants: total tau, phosphorylated tau181 (p-tau181), phosphorylated tau217 (p-tau217), amyloid β 40 and 42, neurofilament light chain, and glial fibrillary acidic protein (GFAP). Muscle strength was measured through the handgrip strength and chair-stand tests. Linear mixed models were used to explore the association between baseline Alzheimer's disease-related biomarkers and muscle strength trajectories.

FINDINGS

The baseline SNAC-K cohort included 3363 individuals, of whom 1953 participants were included in our analyses (mean age 70·2 [SD 9·1] years; 780 [39·9%] male and 1173 [60·1%] female participants). In adjusted models, higher concentrations of p-tau181 (β per year 0·93 [95% CI 0·71 to 1·16]; p<0·0001), p-tau217 (β per year 1·31 [1·03 to 1·58]; p<0·0001), neurofilament light chain (β per year 0·76 [0·56 to 0·96]; p<0·0001), and GFAP (β per year 0·37 [0·21 to 0·53]; p<0·0001) were associated with an accelerated decline of chair-stand performance over time. The adjustment for Mini-Mental State Examination (MMSE) score led to the attenuation of these associations. Higher concentrations of p-tau181 (β per year -0·12 [95% CI -0·17 to -0·07]; p<0·0001), p-tau217 (β per year -0·13 [-0·20 to -0·07]; p<0·0001), and neurofilament light chain (β per year -0·05 [-0·09 to -0·001]; p=0·047) were also associated with faster handgrip strength decline, with no attenuation after adjusting for MMSE score. Sex-specific differences were observed, with female participants showing a stronger association between biomarker concentrations and muscle strength decline than male participants, particularly in the chair-stand test.

INTERPRETATION

Our findings suggest that blood Alzheimer's disease-related biomarkers might help estimate progressive muscle strength decline among older adults, elucidating the influence of brain pathology and cognitive ageing on this association. These Alzheimer's disease-related biomarkers could aid in identifying individuals for early intervention to prevent sarcopenia.

FUNDING

The Swedish Research Council, the Swedish Ministry of Health and Social Affairs, and the County Councils and Municipalities.

Handgrip strength and risk of cognitive impairment across different glucose metabolism statuses: insights from the CHARLS study

Background

Both low handgrip strength (HGS) and abnormal glucose metabolism have been implicated in an increased risk of cognitive impairment. However, whether HGS interacts with glucose metabolism status to influence cognitive function remains unclear. This study explores the relationship between HGS and cognitive impairment risk among middle-aged and older Chinese adults and examines the potential modulation of this association by glucose metabolism status.

Methods

Data from the China Health and Retirement Longitudinal Study (CHARLS) collected in 2011 and 2018 were analyzed, including 7,301 participants aged ≥ 45 years. Cognitive impairment was the primary outcome. Logistic regression and restricted cubic spline (RCS) analyses were applied to evaluate the association between HGS and cognitive impairment risk across different glucose metabolism statuses.

Results

The study included 7,301 participants (mean age: 58.8 ± 8.9 years; 49.3% female). Over a 7-year follow-up, the mean cognitive function score declined from 12.05 ± 3.30 to 7.75 ± 5.70. After adjusting for confounders, logistic regression analyses indicated that higher HGS was significantly associated with a lower risk of cognitive impairment. Participants in the highest HGS quartile (Q4) had a significantly reduced odds of cognitive impairment compared to those in the lowest quartile (Q1) (odds ratio [OR]: 0.59, 95% confidence interval [CI]: 0.49-0.71; P < 0.001). RCS analysis demonstrated a significant negative linear correlation between HGS and cognitive impairment across individuals with normal glucose regulation, prediabetes, and diabetes (P < 0.001). The interaction p-value was 0.277, indicating no significant differences in this association among glucose metabolism subgroups.

Conclusion

Higher HGS is significantly associated with a reduced risk of cognitive impairment among middle-aged and older individuals, irrespective of glucose metabolism status. These findings suggest that HGS assessment could be a valuable universal tool for evaluating cognitive impairment risk, regardless of metabolic conditions.

The Effects of Time-Restricted Feeding on Handgrip Strength, Vigilance, and Perceived Anxiety and Depression in Older Adults: A Comparative Study Between Active and Sedentary Populations

Background and Aims

Ramadan intermittent fasting (RIF), a form of time-restricted feeding, influences various physiological and psychological functions. However, its effects on older adults remain insufficiently understood. This study examined the impact of RIF on physical and mental health parameters, comparing active and sedentary older individuals. Specifically, we assessed handgrip strength (HGS), vigilance performance, anxiety, and depression levels to determine whether regular physical activity mitigates potential adverse effects of RIF.

Methods

Fifty-eight older adults (mean age 62.93 ± 3.99 years; 50% female) participated in this study. They were classified into an active group (n = 26) and sedentary group (n = 32) based on self-reported physical activity levels. Assessments were conducted before and during RIF and included HGS measurement using a handheld dynamometer, a digital psychomotor vigilance test, and validated questionnaires (General Anxiety Disorder-7, Geriatric Depression Scale, and Physical Activity Scale for the Elderly).

Results

During RIF, both groups showed significant improvements in vigilance, anxiety, and depression scores, with more pronounced benefits in the active group. However, sedentary participants experienced a decline in HGS, whereas active individuals maintained stable muscle strength.

Conclusion

Regular physical activity during RIF appears to enhance vigilance and mental health while preventing muscle strength decline in older adults. These findings highlight the importance of maintaining an active lifestyle during RIF to support both physical and mental health in aging populations.

Bidirectional associations of grip strength-gait speed with mild cognitive impairment and specific cognitive abilities among older adults: A longitudinal analysis

BACKGROUND

Previous studies showed that physical performance was associated with mild cognitive impairment (MCI). As the easily measured aging biomarkers, grip strength and gait speed could effectively reflect physical function. However, whether grip strength, gait speed, and the combination of the two were bidirectionally associated with MCI and specific cognitive function domains, have not been explored.

METHODS

The bidirectional relationships between grip strength and MCI, gait speed and MCI, and the combination of grip strength with gait speed and MCI, were examined by generalized estimating equation (GEE). GEE was performed to further estimate the bidirectional relationships between grip strength combined with gait speed and the five domains of cognitive function, respectively.

RESULTS

In total, 2,227 older adults (3 waves) were included. The MCI risk was higher for low grip strength group (OR = 1.78; P < 0.001) compared to normal grip strength group, as well as higher for low gait speed group (OR = 1.71; P < 0.001) compared to normal gait speed group. Low grip strength combined with low gait speed had the maximum associations with MCI (OR = 4.13; P < 0.001) and decline in orientation, immediate memory, delayed memory, attention and calculation, and language. Older adults with MCI and decline in those five domains of cognition also longitudinally related to lower grip strength and lower gait speed.

CONCLUSION

The main findings revealed the importance of regularly monitoring grip strength, gait speed, global cognition, and specific cognitive function domains among older people. Early interventions for grip strength, gait speed, and cognition function might achieve reciprocal benefits.

"Mind-Muscle Connections": Differential Associations Between Handgrip and Upper Body Strength With Cognitive Function in Young and Middle-Aged Adults

The relationship between muscle strength and cognition is widely studied in older adults; however, understanding this association at younger ages may help detect markers of early cognitive changes and inform future interventions. Accordingly, we aimed to identify relationships between handgrip, whole-body, upper body, and lower body strength and cognitive functions. A total of 112 adults (aged 18-50 years) completed comprehensive measures of muscle strength, aerobic capacity, body composition, and cognitive function. Hierarchical linear regressions revealed that individuals with stronger handgrip had better mental rotation performance (standardized β = 0.39); those with greater upper body strength had superior recognition (standardized β = 0.52) and pattern separation abilities (standardized β = 0.39), but whole- and lower body strength were not associated. Results demonstrate the unique relationship between upper body strength and aspects of cognitive function, in addition to differential associations of upper body and handgrip strength with encoding, retrieval, and spatial skills. The current findings establish an association between strength and cognitive function earlier than previously thought.

Association between changes in physical functions and risk of stroke: a prospective cohort study

BACKGROUND

The association between changes in physical functions and stroke incidence remains uncertain.

METHODS

A total of 7978 participants without stroke from the China Health and Retirement Longitudinal Study (CHARLS) were recruited in 2011-2012 and followed up until 2020. We assessed annual changes in physical functions from 2011 to 2015, including absolute grip strength, relative grip strength, walking speed, chair-rising time and standing balance. The Cox proportional hazards model was applied to assess the longitudinal associations between annual changes in physical functions and stroke. Restricted cubic spline analyses were used to explore the dose-response relationships.

RESULTS

During 71 714 person-years of follow-up, 549 incident stroke cases were reported. For each 1-kg absolute grip strength increment, 0.1-unit relative grip strength increment, or 1-point standing balance test score increment, the hazard of stroke was reduced by 12% [hazard ratio (HR): 0.88; 95% confidence interval (CI): 0.84-0.93], 53% (HR: 0.47; 95% CI: 0.34-0.64), 55% (HR: 0.45; 95% CI: 0.30-0.67), respectively. We found a negative linear dose-response association of the annual change in absolute and relative grip strength with incident stroke, as well as a nonlinear association between the annual change in standing balance and incident stroke. However, neither the annual change in walking speed nor chair-rising time was related to the incident stroke.

CONCLUSIONS

A greater improvement in absolute grip strength, relative grip strength or standing balance was suggested to be associated with a lower risk of stroke amongst middle-aged and older people. These objectively measured physical function changes are imperative for high-risk population classification and stroke prevention.

Association of handgrip strength weakness and asymmetry with cognitive impairment and depressive symptoms in older Chinese adults

This study investigated the association between handgrip strength (HGS) asymmetry and weakness with cognitive function and depressive symptoms among 920 community-dwelling adults aged above 60 years in suburban Shanghai. Participants were selected using a multistage cluster-stratified sampling approach. Assessments included HGS measured with a dynamometer, the Montreal Cognitive Assessment (MoCA) for cognition, and the Geriatric Depression Scale (GDS) for depressive symptoms. Restricted cubic splines revealed a positive association between dominant HGS and MoCA scores, indicating better cognitive performance, and a negative association with GDS scores, suggesting fewer depressive symptoms. The association between the HGS ratio and MoCA scores and the HGS ratio and GDS scores varied by sex. Women with HGS weakness alone (odds ratio (OR) = 2.00, 95% confidence interval (CI) = 1.17-3.37), asymmetry alone (OR = 1.93, 95% CI = 1.14-3.29), or weakness and asymmetry together (OR = 2.57, 95% CI = 1.48-4.46) had a significantly increased risk of cognitive impairment. However, no such associations observed in men. These findings suggest that HGS weakness and asymmetrical HGS may be associated with a higher risk of cognitive decline and depressive symptoms, particularly in women. This study emphasizes the need for sex-specific assessments and prevention strategies to address cognitive and mental health issues among older adults.

Protective role of parenthood on age-related brain function in mid- to late-life

The experience of human parenthood is near ubiquitous and can profoundly alter one's body, mind, and environment. However, we know very little about the long-term neural effects of parenthood for parents themselves, or the implications of pregnancy and caregiving experience on the aging adult brain. Here, we investigate the link between the number of children parented and age on brain function in 19,964 females and 17,607 males from the UK Biobank. In both females and males, parenthood was positively correlated with functional connectivity, such that higher number of children parented was associated with higher connectivity, particularly within the somato/motor network. Critically, the spatial topography of parenthood-linked effects was inversely correlated with the impact of age on functional connectivity across the brain for both females and males, such that the connections that were positively correlated with number of children were negatively correlated with age. This result suggests that a higher number of children is associated with patterns of brain function in the opposite direction to age-related alterations. Overall, these results indicate that the changes accompanying parenthood may confer benefits to brain health across the lifespan, altering aging trajectories, consistent with animal models of parenthood and preliminary findings of "younger-looking" brain structure in human parents. Observing this effect in both females and males implicates the caregiving environment, rather than pregnancy alone, and highlights the importance of future work to disentangle the underlying mechanisms related to the direct impact of caregiving, the indirect impact of the environment, and the result of covarying sociodemographic factors.

Event-related theta synchronization over sensorimotor areas differs between younger and older adults and is related to bimanual motor control

When engaged in dynamic or continuous movements, action initiation involves modifying an ongoing motor program rather than initiating it from rest. Event-related theta synchronization over sensorimotor areas is a neurophysiological marker for modifying motor programs. We used electroencephalography (EEG) to examine how task complexity and age affect event-related synchronization (ERS) in the theta band during a dynamic bimanual, visuomotor pinch force task. Older (mean age = 68) and younger (mean age = 26) participants performed symmetric (SYM) and asymmetric (ASYM) bimanual pinch force adjustments. Trials began with a visually cued contraction from a baseline force to a novel target force (P1). Force had to be maintained at the target until a visually cued return to the familiar baseline (P2). Older adults reacted slower across task conditions, and their accuracy decreased more when shifting from the SYM to the ASYM condition. Older adults also displayed lower theta ERS across conditions. Additionally, older adults were not able to modulate theta expression based on whether a force change was initiated to a novel target or back to baseline. Younger adults showed significantly stronger theta ERS after P1-cues compared to P2-cues, while the theta response to P1 and P2 cues was not different in older adults. Older adults also showed stronger lateralization, displaying higher theta ERS over the dominant motor cortex. Finally, event-related theta synchronization appeared to be behaviorally relevant across groups and correlated with task performance. Together, the results show that theta ERS over sensorimotor areas is a strong, age-sensitive marker of dynamic pinch force adjustments showing an age-related reduction in specificity with reduced context-dependent modulations and more imbalanced bimanual activation.

Effects of 12-week whole-body vibration training versus resistance training in older people with sarcopenia

Sarcopenia is a syndrome commonly found in older people. The aim of this study was to evaluate the effects of whole-body vibration training (WBVT) and resistance training (RT) on body composition, muscle strength, physical performance and blood biomarkers in older people with sarcopenia. We conducted a 12-week, 3-times-weekly assessor-blinded, randomized controlled trial of 27 older people with sarcopenia aged ≥ 65 years. Subjects were randomized into WBVT group (n = 14) and RT group (n = 13). The primary outcome was knee extension strength (KES). Secondary outcomes were body composition [body weight, body mass index (BMI), percentage of body fat (PBF), and appendicular skeletal muscle mass index (ASMI)], muscle strength [handgrip strength (HS)], physical performance [gait speed (GS), 5-time chair stand test (5CST), and short physical performance battery (SPPB)], blood biomarkers (inflammatory factors, hormones, growth factors, and muscle injury biomarker), and quality of life questionnaire [medical outcomes study short-form 36 (SF-36)]. After 12-week intervention, in the WBVT group, we observed significant improvements in body composition (weight, BMI, PBF and ASMI), muscle strength (KES), physical performance (GS, SPPB and 5CST), blood biomarkers [insulin-like growth factor 1 (IGF-1), growth hormone, follistatin (FST) and creatine kinase (CK)] and quality of life. In the RT group, we observed significant improvements in body composition (weight, BMI and PBF), muscle strength (KES), physical performance (GS and SPPB), blood biomarkers (growth hormone, FST and CK) and quality of life. Between-group comparisons were only significant for KES (P = 0.007) and the role-physical (RP) dimension of the SF-36 (P = 0.007). WBVT and RT both improved the physical condition of older people with sarcopenia. RT excelled in muscle strength, but WBVT offered an alternative for those with restrictions. WBVT's low risk and flexibility suited diverse conditions, providing a new rehabilitation option for patients with sarcopenia.

Investigating Modifiable Factors Associated with Cognitive Decline: Insights from the UK Biobank

Objectives: Given the escalating global prevalence of age-related cognitive impairments, identifying modifiable factors is crucial for developing targeted interventions. Methods: After excluding participants with dementia and substantial missing data, 453,950 individuals from UK Biobank (UKB) were included. Cognitive decline was assessed across four cognitive domains. The top 10% exhibiting the greatest decline were categorized as the "Cognitively At-Risk Population". Eighty-three potential factors from three categories were analyzed. Univariate and multivariate Cox proportional hazards models were employed to assess the independent and joint effects of these factors on cognitive decline. Population Attributable Fractions (PAFs) were calculated to estimate the potential impact of eliminating each risk category. Results: Our findings revealed a significant impact of unfavorable medical and psychiatric histories on processing speed and visual episodic memory decline (Hazard Ratio (HR) = 1.34, 95% CI: 1.20-1.51, p = 6.06 × 10⁻7; HR = 1.50, 95% CI: 1.22-1.86, p = 1.62 × 10⁻4, respectively). Furthermore, PAF analysis indicated that physiological and biochemical markers were the most critical risk category for preventing processing speed decline (PAF = 7.03%), while social and behavioral factors exerted the greatest influence on preventing visual episodic memory decline (PAF = 9.68%). Higher education, socioeconomic status, and handgrip strength emerged as protective factors, whereas high body mass index (BMI), hypertension, and depression were detrimental. Conclusions: By identifying this high-risk group and quantifying the impact of modifiable factors, this study provides valuable insights for developing targeted interventions to delay cognitive decline and improve public health outcomes in middle-aged and older adults.

Correlates of gait speed changes during uneven terrain walking in older adults: differential roles of cognitive and sensorimotor function

Many studies of walking function and aging have measured walking on flat surfaces with and without dual-tasking (i.e., performing a concurrent cognitive task). Walking in the community increases the complexity with surface undulations and varying surface types. We hypothesized that changes in walking resulting from increasing terrain unevenness would be better predicted by sensorimotor function than cognitive function. Sixty-three community-dwelling older adults (65-93 yrs old; 32 males) performed overground walking under four uneven terrain conditions (Flat, Low, Medium, and High unevenness). Cognitive (cognitive flexibility, working memory, inhibition) and sensorimotor assessments (grip strength, 2-pt discrimination, pressure pain threshold) were measured as the primary predictors of walking performance. We found that walking speed decreased linearly with more elevated uneven terrain conditions across all participants; this was accentuated in older adults with lower mobility function. Greater rates of decline in walking speed from flat to uneven terrain were associated with worse attention and inhibitory function as well as lower 2-point tactile discrimination. Findings suggest that greater rates of decline with elevated terrain walking are associated with lower mobility function, lower executive functions and less somatosensation.

Sex-Based Effects on Muscle Oxygenation During Repeated Maximal Intermittent Handgrip Exercise

BACKGROUND

This investigation aimed to examine sex-based differences in deoxy[heme] (HHb), tissue saturation (StO2), and force-deoxygenation ratio (FD) of the forearm flexor muscles during a maximal-effort intermittent fatiguing handgrip protocol.

METHODS

Thirty-three healthy males (n = 15) and females (n = 18) completed a fatiguing handgrip protocol consisting of 60 4 s contractions separated by a 1 s rest. Near-infrared spectroscopy was used to measure muscle oxygenation before, during, and after the protocol.

RESULTS

Sex differences in HHb (p = 0.033) and StO2 (p = 0.021) were observed with significantly greater values for females (HHb: 110.204 ± 12.626% of baseline; StO2: 72.091 ± 5.812%) in comparison to males (HHb: 101.153 ± 12.847% of baseline; StO2: 66.978 ± 7.799%). Females (0.199 ± 0.081 AU) also demonstrated significantly (p = 0.001) lower FD in comparison to males (0.216 ± 0.094 AU). However, males (b = -0.023 ± 0.008 AU) demonstrated a significantly (p < 0.001) greater rate of decline in FD in comparison to females (b = -0.017 ± 0.006 AU).

CONCLUSIONS

Prior to, during, and after a maximal-effort intermittent fatiguing handgrip fatiguing protocol, males demonstrate significantly lower StO2 than females and a faster rate of decline in FD. Moreover, females demonstrate greater HHb values than males when assessed relative to a resting baseline.

Profile of non-invasive physical health indicators associated with cognitive performance in Chinese older adults: evidence from the China Health and Retirement Longitudinal Study

BACKGROUND

Existing studies have indicated the potential role of non-invasive physical health indicators as an early detector of mild cognitive impairment (MCI) in older adults. However, evidence is lacking in determining the appropriate physical health indicators for early screening of cognitive decline in each domain. Therefore, the current study aimed to establish a comprehensive physical health indicators profile in association with cognitive performance.

METHODS

The present study utilized a three-year longitudinal cohort design, with data from the China Health and Retirement Longitudinal Study (CHARLS). 4,869 participants aged 60-97 years from CHARLS wave 2015 and 2018 who were cognitively and physically healthy were included in analysis. Physical functions (BMI, grip strength, blood pressure, balance tests, course walking time, repeated chair stands, and pulmonary function) were objectively measured by physical tasks. Cognitive performance domains (general cognition, episodic memory, executive function, verbal fluency, orientation, and language-and-praxis) were measured through standardised interviews and cognitive tasks. Multiple linear regression models were conducted to explore the association between physical health indicators and cognitive performance. Subgroup analysis was conducted to identify sex-specific factors.

RESULTS

Pulmonary function was identified as associated with all domains of cognitive performance in older adults (β ranged between 0.05 and 0.08). Right grip strength was also identified as an important factor associated with all cognitive domains except general cognition (β ranged between 0.04 and 0.12). Subgroup analysis revealed that the association between physical health indicators and cognitive performance is more pronounced in males than in females.

CONCLUSIONS

A profile of non-invasive physical health indicators associated with cognitive performance was established, which warrants future incorporation of non-invasive physical health indicators in early risk screening systems for MCI, enabling timely intervention and prevention in older adults. Future studies can delve deeper into the mechanisms underlying this full-dimensional relationship between physical and cognitive domains.

Plasma brain-derived neurotrophic factor concentrations are elevated in community-dwelling adults with sarcopenia

BACKGROUND

The scalability of a blood-based sarcopenia assessment has generated interest in circulating markers that may enhance management strategies. Data regarding the relevance of brain derived neurotrophic factor (BDNF), a regulator of neuroplasticity, to sarcopenia in community-dwelling adults are scarce. We examined the association between plasma BDNF concentrations, sarcopenia and individual sarcopenia signatures in a well-characterised adult cohort.

METHODS

Participants included 246 men and women aged 50-82 years (mean age = 63.6 years; 52% female). Muscle strength and skeletal muscle index (SMI) were assessed by hand dynamometry and dual-energy X-ray absorptiometry. Plasma BDNF concentrations were determined, in duplicate, with commercially available enzyme-linked immunosorbent assays. Sarcopenia and individual signatures of sarcopenia (i.e. low grip strength or low SMI) were diagnosed according to the EWGSOP2 algorithm.

RESULTS

Plasma BDNF concentrations were 47.6% higher in participants with sarcopenia than controls (P = 0.005), and demonstrated acceptable diagnostic accuracy (areas under the curves = 0.702, 95%CI = 0.597-0.806, P = 0.002, optimal cut-off >1645 pg/ml). Plasma BDNF concentration >1645 pg/ml was associated with 2.83 greater odds for sarcopenia (95%CI = 1.13-7.11, P = 0.027), than ≤1645 pg/ml, whilst a BDNF Z-score ≥2 was associated with 5.14 higher odds for sarcopenia (95%CI = 1.16-22.82, P = 0.031), than a Z-score <1. Covariates included sex, age, body mass index, habitual physical activity, smoking status, alcohol consumption, comorbidity and educational attainment.

CONCLUSION

Circulating BDNF concentrations are elevated in community-dwelling men and women with sarcopenia, which may reflect increased neuromuscular remodelling in these people. Our findings complement existing data, supporting the presence of an intricate relationship between neural integrity and skeletal muscle health. Future studies are needed to establish the mechanistic pathways that may underpin the associations.

Relationships between muscle strength, lung function, and cognitive function in Chinese middle-aged and older adults: A study based on the China health and retirement longitudinal study (CHARLS)

OBJECTIVE

As the population ages, concerns about cognitive decline have become increasingly relevant in medical consultations. This study aims to analyze the interaction between muscle strength, lung function, and cognitive function in Chinese middle-aged and older adults, providing a theoretical basis for better prevention of cognitive decline.

METHODS

This study used data from the China Health and Retirement Longitudinal Study (CHARLS) wave 3, including 13 716 participants aged 45 years or older. Cognitive function was assessed through two dimensions, resulting in a total score ranging from 0 to 31 points, with higher scores indicating better cognitive function. Muscle strength was measured using normalized grip strength and chair-standing time, while lung function was evaluated using peak expiratory flow (PEF).

RESULTS

Total cognitive function scores exhibited significant correlations with grip strength, chair-standing time, and PEF. Muscle strength and lung function demonstrated significant associations with cognitive function, with lung function emerging as a notable mediating factor. This relationship persisted even after adjusting for potential confounding variables. Specifically, PEF played a substantial mediating role in linking grip strength to cognitive function scores (estimated indirect effect = 0.0132, boot-strapped standard error = 0.0015, boot-strapped standard 95% confidence interval = 0.0104, 0.0162). Additionally, PEF served as a significant mediator in the association between chair-standing time and cognitive function scores (estimated indirect effect = -0.0204, boot-strapped standard error = 0.0023, boot-strapped standard 95% confidence interval = -0.0251, -0.0159).

CONCLUSION

The study highlights the importance of addressing declines in muscle strength and lung function to identify risk factors associated with cognitive function. Understanding these relationships can provide insights into potential pathways linking these variables and may aid in better prevention of cognitive decline. Further long-term longitudinal cohort studies are needed to explore the causality between these factors.

Relationship between handgrip strength and timed up-and-go test on hospitalization costs in older adults: a population-based study

BACKGROUND

Weak handgrip strength and slow timed up-and-go (TUG) time are known risk factors for hospitalization among older adults; however, few studies have investigated the relationships between these physical tests and future hospitalization costs.

METHODS

We used data from 13,613 participants in the population-based Singapore Chinese Health Study who underwent assessment for handgrip strength and TUG time at a mean age of 74 years. Hospitalization costs for the subsequent year, among those who survived for at least one year thereafter, were ascertained via linkage with administrative healthcare finance data. We analyzed costs using a two-part model that contained a probit regression model in the first part, and a generalized linear regression model with gamma distribution and log link in the second.

RESULTS

Handgrip strength showed a dose-dependent inverse relationship with hospitalization costs (Ptrend<0.001). Compared to the strongest quartile, participants in the weakest quartile experienced a 38.2% (95% CI: 18.0-58.5%) increase of US$599 (US$281-US$917) in mean costs. Conversely, TUG time demonstrated a dose-dependent positive association with hospitalization costs (Ptrend<0.001). Compared to the fastest quartile, participants in the slowest quartile had a 103.0% (72.1-133.9%) increase of US$1431 (US$1002-US$1859) in mean costs. We then examined combinations of handgrip strength and TUG time. Compared to participants who were both strong and fast, participants who were either weak or slow only had 12.9-48.7% higher mean costs. Meanwhile, participants who were both weak and slow experienced a 99.9% (68.5-131.4%) increase of US$1630 (US$1116-US$2144) in mean costs.

CONCLUSIONS

Weak handgrip strength and slow TUG time were independently associated with increased hospitalization costs among older adults.

Correlation of muscle strength, information processing speed and cognitive function in the elderly with cognitive impairment--evidence from EEG

Objective

This study investigates the interplay between muscle strength, information processing speed, EEG-specific biomarkers, and cognitive function in elderly individuals with cognitive impairments, emphasizing the mediating roles of information processing speed and EEG-specific biomarkers.

Method

A cross-sectional study design was employed to recruit 151 elderly participants. The participants underwent grip strength and 30-s sit-to-stand tests to assess muscle strength, completed the Trail Making Test part A (TMT-A) and the Symbol Digit Modality Test (SDMT) to evaluate information processing speed, and utilized the Montreal Cognitive Assessment (MOCA) to gauge cognitive function. Additionally, EEG signals were recorded for 5 min to capture neural activity.

Results

The difference in information processing speed among elderly individuals with varying degrees of cognitive impairment was statistically significant (p < 0.001). A significant negative correlation was observed between the MoCA score and the time consumption of TMT-A (r = -0.402, p < 0.01), and a significant positive correlation was found between the MoCA score and the SDMT score (r = 0.609, p < 0.01). Grip strength was negatively correlated with the time consumption of TMT-A (r = -0.336, p < 0.01) and positively correlated with the SDMT score (r = 0.336, p < 0.01). A significant negative correlation was found between the 30-s sit-to-stand test and the time consumption of TMT-A (r = -0.273, p < 0.01), and a significant positive correlation was observed between the 30-s sit-to-stand test and the SDMT score (r = 0.372, p < 0.01). Additionally, we observed that the α1 power value indicators were significantly correlated with the MoCA score, the time consumption of TMT-A, and the SDMT score (all p < 0.01). The α1 power values at F7 + F8 and T5 + T6 were identified as sensitive EEG indicators for muscle strength and information processing speed. The EEG-specific indicators (B = 0.019, 95% CI: 0.003, 0.047) and information processing speed (B = 0.137, 95% CI: 0.096, 0.292) were found to partially mediate the relationship between grip strength and MoCA scores, with information processing speed exerting a stronger mediating effect.

Conclusion

Specific patterns were observed in the EEG of elderly individuals with cognitive impairments, which could objectively assess the risk of cognitive decline in this population. Muscle strength, information processing speed, and EEG-specific biomarkers were closely associated with cognitive function in elderly individuals. The potential pathway of interaction-muscle strength → EEG-specific biomarkers → information processing speed → cognitive function-provides valuable insights into advancing the field of cognitive research in the elderly.

Reversing Decline in Aging Muscles: Expected Trends, Impacts and Remedies

Background: Age-related decline in musculoskeletal function is a significant concern, particularly in Western countries facing demographic shifts and increased healthcare demands. This review examines the typical trajectories of musculoskeletal deterioration with age and evaluates the effectiveness of various interventions in preventing or reversing these changes. Methods: The review analyzes documented rates of decline across multiple parameters, including muscle mass, Type II muscle fiber reduction, and decreased motor unit firing rates. It examines evidence from studies on targeted interventions aimed at reversing these trends or preventing further decline. Results: The evidence suggests that multimodal interventions, including strength training can effectively maintain or improve physical function in aging adults. These interventions have shown potential in altering the trajectory of age-related decline in musculoskeletal function. Conclusions. The findings of this review have important implications for healthcare providers and policymakers in addressing the challenges of an aging population. By providing a framework for understanding and addressing age-related physical decline through evidence-based interventions, this review offers potential strategies for reducing healthcare costs and improving the quality of life for older adults.

Association of handgrip strength asymmetry and weakness with intrinsic capacity impairment among older adults in China

BACKGROUND

Declining intrinsic capacity (IC) significantly impacts health outcomes in aging populations. While weak handgrip strength (HGS) is associated with IC impairment, the role of HGS asymmetry remains unclear, especially among older Chinese cohorts.

METHODS

We included participants aged ≥60 years from the 2015 wave of the China Health and Retirement Longitudinal Study (CHARLS). IC was evaluated across cognitive, locomotion, psychological, sensory, and vitality domains. Asymmetry and weakness were measured using the maximum value of HGS. Logistic regression models were employed to examine the association of the individual and combined groupings of HGS asymmetry and weakness with IC impairment (a total score ≥ 2 across five domains). The potential non-linear relationship was explored using a restricted cubic spline (RCS) model.

RESULTS

Of the 4798 participants included (median age 66.0 years, IQR 63.0-71.0 years; 56.9 % male), 35.2 % had IC impairment. HGS asymmetry (OR = 1.26, 95 % CI: 1.11-1.43) and weakness (OR = 2.09, 95 % CI: 1.78-2.45) were both independent risk factors for IC impairment. Notably, participants experiencing both HGS asymmetry and weakness were at even higher risk of IC impairment (OR = 2.47, 95 % CI: 1.99-3.08), suggesting compounded effects on IC. Further subgroup analysis showed significant associations between HGS status and impairments in specific IC domains, particularly in locomotion. In contrast to other domains, it was the Weakness only group, rather than the Both group, that had the highest risk of vitality impairment. There was a U-shaped relationship between HGS asymmetry and IC impairment.

CONCLUSIONS

HGS asymmetry and weakness were associated with an increased risk of composite and individual domain IC impairment. Assessing and maintaining HGS symmetry and strength may have implications for the early identification of individuals at risk for IC impairment and the prevention of related adverse health outcomes.

Exhaled breath metabolites reveal postmenopausal gut-bone cross-talk and non-invasive markers for osteoporosis

BACKGROUND

Menopause driven decline in estrogen exposes women to risk of osteoporosis. Detection of early onset and silent progression are keys to prevent fractures and associated burdens.

METHODS

In a discovery cohort of 120 postmenopausal women, we combined repeated quantitative pulse-echo ultrasonography of bone, assessment of grip strength and serum bone markers with mass-spectrometric analysis of exhaled metabolites to find breath volatile markers and quantitative cutoff levels for osteoporosis. Obtained markers and cutoffs were validated in an independent cohort of 49 age-matched women with six months apart seasonal follow-ups.

RESULTS

Here, within the discovery cohort, concentrations of exhaled end-tidal dimethyl sulfide (DMS), allyl-methyl sulfide, butanethiol and butyric acid are increased (p ≤ 0.005) pronouncedly in subjects with bone mineral density (BMD) at high-risk of osteoporosis and fracture, when compared to subjects with normal BMD. Increased age and decreased grip strength are concomitant. All changes are reproduced during independent validation and seasonal follow-ups. Exhaled metabolite expressions remain age independent. Serum markers show random expressions without reproducibility. DMS exhalations differs between patients with recent, old and without fractures. Metabolite exhalations and BMDs are down-regulated during winter. ROC analysis in discovery cohort yields high classification accuracy of DMS with a cutoff for osteoporosis, which predicts subjects at high-risk within the independent validation cohort with >91% sensitivity and specificity.

CONCLUSIONS

Non-invasive analysis of exhaled DMS allowed more reliable classification of osteoporosis risk than conventional serum markers. We identified associations of exhaled organosulfur and short-chain fatty acids to bone metabolism in postmenopausal osteoporosis via a gut-bone axis.

The Relationship Between Health Parameters, Body Size, Elements of Lifestyle, and Hand Grip Strength in a Group of Patients with Type 2 Diabetes, Aged 40-98, from Ulaanbaatar, Mongolia

Background/Objectives: Decreased muscle strength and lower hand grip strength (HGS) values are observed in patients with type 2 diabetes (T2D). This study aimed to present the values of hand grip strength as a valuable tool in T2D treatment monitoring in the context of body size and lifestyle elements in 347 patients with type 2 diabetes from Ulaanbaatar, Mongolia. Methods: A retrospective cross-sectional study was performed at hospitals in Ulaanbaatar, Mongolia. The maximum grip strengths of the right and left hands were measured three times, alternatively, using a digital hand dynamometer. The maximum grip strength of the dominant hand was used for the analysis. Results: The values of HGS in both hands dropped with increased age, systolic blood pressure (SBP), the duration of diabetes, and low glucose blood levels, whereas they increased with height. Patients who smoked had the lowest three values of HGS (the average value for each hand), whereas patients who quit smoking had the highest values. Second-order interactions between diastolic blood pressure (DBP) and sex showed a significant effect on the average HGS of both hands and for the left hand in particular (where HGS decreased only in females, whereas it increased in males). Conclusions: HGS is influenced by important socioeconomic and anthropometric factors in patients with type 2 diabetes, making it a valuable indicator of general health.

GDF-15 as a proxy for epigenetic aging: associations with biological age markers, and physical function

Growth differentiation factor 15 (GDF-15) has emerged as a significant biomarker of aging, linked to various physiological and pathological processes. This study investigates circulating GDF-15 levels in a cohort of healthy individuals from the Balearic Islands, exploring its associations with biological age markers, including multiple DNA methylation (DNAm) clocks, physical performance, and other age-related biomarkers. Seventy-two participants were assessed for general health, body composition, and physical function, with GDF-15 levels quantified using ELISA. Our results indicate that GDF-15 levels significantly increase with age, particularly in individuals over 60. Strong positive correlations were observed between GDF-15 levels and DNAm GrimAge, DNAm PhenoAge, Hannum, and Zhang clocks, suggesting that GDF-15 could serve as a proxy for epigenetic aging. Additionally, GDF-15 levels were linked to markers of impaired glycemic control, systemic inflammation, and physical decline, including decreased lung function and grip strength, especially in men. These findings highlight the use of GDF-15 as a biomarker for aging and age-related functional decline. Given that GDF-15 is easier to measure than DNA methylation, it has the potential to be more readily implemented in clinical settings for broader health assessment and management.

Association of handgrip strength weakness and asymmetry with low physical performance among Chinese older people

BACKGROUND

Handgrip strength (HGS) weakness and asymmetry are both abnormal conditions of upper-limb muscle strength. The association between HGS weakness and physical performance is controversial, and the link between HGS asymmetry and physical performance remains unclear.

AIMS

This study aimed to investigate the associations of HGS weakness and asymmetry separately and concurrently with low physical performance among Chinese older people.

METHODS

The study used two waves of data from China Health and Retirement Longitudinal Study (CHARLS) in 2013 and 2015. HGS weakness and asymmetry were defined according to the maximal HGS and the HGS ratio, respectively. Participants were classified into 4 groups according to HGS status: normal, asymmetry only, weakness only, and concurrent weakness and asymmetry. The logistic regression model was used to investigate the cross-sectional association between low physical performance and each of maximal HGS, HGS ratio, and HGS status, as well as the prospective association between baseline HGS status and new-onset physical performance decline after two years.

RESULTS

Participants with HGS asymmetry only, weakness only, and two abnormalities showed a higher prevalence of low physical performance when asymmetry defined as an HGS ratio exceeding 1.20 and 1.30 (all, p < 0.001), with the greatest odds in those with two abnormalities (20% threshold: OR 3.83; 30% threshold: OR 5.41). The longitudinal analysis found that HGS weakness can predict the new-onset low physical performance over a two-year period, with concurrent HGS asymmetry further increased the future risk of physical performance decline.

CONCLUSIONS

Both HGS weakness and asymmetry were associated with a higher prevalence of low physical performance, in an additive way. This study will help screen older people with low physical performance more efficiently, and identify those at higher risk of developing new-onset physical performance decline within two years.

Association of handgrip strength asymmetry and weakness with depression among middle-aged and older population in China: A cohort study

BACKGROUND

Handgrip strength (HGS) weakness and asymmetry were recently reported to be associated with age-related health conditions. However, little is known about their combined effects on depression. We aimed to explore the joint association of HGS asymmetry and weakness with depressive symptoms in Chinese middle and older aged population.

METHODS

8700 participants aged ≥45 years were enrolled from China Health and Retirement Longitudinal Study (2015-2018). HGS weakness was determined as maximal HGS < 28 kg in males and <18 kg in females. HGS asymmetry was measured by HGS ratio and was defined using two different rules. Specifically, HGS ratio < 0.90 or >1.10 (10 % rule) and <0.80 or >1.20 (20 % rule) were considered as asymmetry. Participants were classified into four groups: normal and symmetric HGS, asymmetry only, weakness only, and both weakness and asymmetry. Depressive symptoms were assessed by the 10-item Center for Epidemiologic Studies Depression Scale, with scores ≥12 defined as depression. The logistic regression and multiple linear regression models were conducted to estimate the associations between HGS status and depressive symptoms.

RESULTS

The three-year incidence of depression was 19.2 %. After adjusting for covariates, compared to normal and symmetric HGS, participants with both HGS asymmetry and weakness showed the greatest risk of incident depression (10 % rule: OR 1.55, 95 % CI 1.19-2.02; 20 % rule: OR 1.71, 95 % CI 1.16-2.50). The coexistence of asymmetry and weakness was related to a significant increase in depression score (10 % rule: β 0.96, 95 % CI 0.38-1.54; 20 % rule: β 0.94, 95 % CI 0.08-1.81). The complete case analysis supported the results, and the associations were not modified by age, sex, and hand dominance.

LIMITATIONS

Depressive assessment was based on self-reported screening instrument.

CONCLUSIONS

The presence of both HGS asymmetry and weakness was associated with a higher risk of depression. Examining HGS asymmetry along with weakness may aid in identifying individuals at risk of depression to enable early interventions.

Comparative effects of open-skill and closed-skill sports on executive function in university students: a 16-week quasi-experimental study

Introduction

Previous reviews have often concluded that open-skill sports are more effective at enhancing executive function (EF) than closed-skill sports. However, this conclusion may not hold for closed-skill sports with high cognitive demands, such as golf. This study aimed to compare the effects of football (open-skill) and golf (closed-skill) training on enhancing EF in university students.

Method

Using a quasi-experimental, pre-post test design, 63 male participants were assigned to three groups: football (n = 21), golf (n = 21), and a sedentary control group (n = 21). Over 16 weeks of training, the intervention groups engaged in four 90-min training sessions per week, while the control group attended one 80-min physical education class per week. Assessments were conducted before and after the intervention. EFs, including inhibition control and working memory, were assessed using the Flanker task and Corsi-block tapping task, respectively. Cardiovascular fitness (CRF) was measured by the multi-stage fitness test.

Results

The golf group showed significant improvements in inhibition control from pre- to post-intervention (p = 0.02, d = 0.26), while the football and control groups did not exhibit significant changes. Post-intervention comparisons indicated no significant differences in EF performance between the golf and football groups; however, both outperformed the control group (golf, p = 0.002, d = 0.99; football, p = 0.01, d = 0.67). No significant improvement was observed in working memory for any group. Additionally, changes in CRF were not significantly correlated with EF performance.

Conclusion

This study provides preliminary evidence that golf, a closed-skill sport with high cognitive demands, can effectively improve inhibitory control after 16 weeks of training. This improvement is comparable to that observed in football, an open-skill sport. The findings also suggest that the cognitive demands of the sports, rather than improvements in physical fitness, may be primarily responsible for the enhancements in EF.

Effects on older adult Women's precision, strength and flexibility from resistance training and handicrafts practice

INTRODUCTION

As individuals age, they experience a gradual decline in strength, flexibility, and precision control. While resistance training has shown positive effects on aging, little is known about how beneficial handicrafts could be in effectively promoting motor improvements in aging. This study aimed to compare manual precision, manual grip strength, and upper limb flexibility among three groups of older adult women: (a) regular practitioners of resistance training, (b) regular practitioners of handicrafts, and (c) insufficiently active participants who did not engage in either regular resistance training or handicraft practice.

METHODS

A total of 30 women (mean age = 67.86, SD = 7.01) were divided equally into the three groups (n = 10 per group). The participants were asked to perform a manual manipulative precision test, a manual grip strength test, and an upper limb flexibility test.

RESULTS

The participants in the resistance training group exhibited superior precision and strength compared to those in the handicraft group, as well as better precision, strength, and flexibility compared to the control group participants. The handicraft group demonstrated better precision and upper limb flexibility compared to the control group.

CONCLUSION

Therefore, while resistance training was particularly beneficial for improving these motor skills, engaging in handicrafts also proved to be an effective means of maintaining and/or enhancing certain important motor abilities.

The relationship between asymmetrical grip strength criteria and fall incidence among middle-aged and older Chinese adults

PURPOSE

Current handgrip strength (HGS) protocols employ a variety of criteria, affecting the assessment of asymmetric HGS. The impact of these different criteria on fall prediction is understudied. This study was devised to compare the relative performance of average and maximum HGS asymmetry criteria as tools to predict fall incidence among middle-aged or older adults in China.

METHODS

9627 Chinese adults 50 + years of age who were participants in the China Health and Retirement Longitudinal Study (2013-2015 waves) were evaluated. The measurement of HGS was achieved based on either the maximum recorded value (HGSmax) or the average (HGSave), and these values were employed for the calculation of HGS asymmetry. Fall incidence over a 2-year period was evaluated based on self-reported data. Logistic regression analyses were utilized to determine the predictive performance of HGSmax asymmetry or HGSave asymmetry when gaging 2-year fall risk.

RESULTS

Significant differences in overall rates of HGS asymmetry and the rates of subdivisions thereof were observed when comparing the HGSmax and HGSave criteria, with moderate consistency (kappa = 0.599, p < 0.001). Over the 2-year follow-up period, 1743 fall incidents were recorded. Adjusted logistic regression models indicated that only HGSmax asymmetry > 30.0% was significantly related to fall risk (p = 0.034, odds ratio = 1.36, 95% confidence interval: 1.02-1.81).

CONCLUSION

These findings highlight the importance of HGS criteria in detecting HGS asymmetry, and suggest that HGSmax is a more robust criterion for predicting fall risk among Chinese adults 50 + years of age.

Sarcopenia in older patients with idiopathic normal pressure hydrocephalus: an observational study from a single geriatric clinic in Turkey

OBJECTIVE

Idiopathic normal pressure hydrocephalus (iNPH), a classical triad of gait abnormality, cognitive disturbance, and urinary incontinence, increases in prevalence with aging. Sarcopenia is also characterized by low muscle strength and mass, contributing to gait difficulty. Gait abnormality and lower physical activity also lead to the development of sarcopenia. Therefore, this study aims to investigate the relationship between sarcopenia and iNPH.

METHODS

A total of 327 participants were included in this retrospective cross-sectional study. Demographic and clinical characteristics, including age, sex, comorbidity index, number of medications, recurrent falls in the last year, laboratory findings and comprehensive geriatric assessment (CGA) parameters were recorded. Sarcopenia was defined according to the EGWSOP2 criteria. The relationship between sarcopenia and iNPH was assessed with regression analysis.

RESULTS

There were 51 participants with iNPH, 49% female, mean age 78 years (SD 5.7) and 276 control participants, 74% female, mean age 72 years (SD 6.1). The sarcopenia rates in patients with iNPH and controls were 19.6% and 2.5%, respectively (p < 0.01). The odds of probable sarcopenia were 3.89 times, and the slow gait speed was 8.47 times higher in iNPH patients than in controls after adjusting for age, sex, and the other confounders. The Mini-Mental State Examination score (p = 0.042, OR = 0.869 with 95% CI:0.759-0.995) was associated with probable sarcopenia among patients with iNPH.

CONCLUSION

This study demonstrated that sarcopenia was common in older patients with iNPH, which seems to be closely associated with decreased muscle strength and slowed gait speed. Thus, considering the potential untoward effects of both diseases, it is important for physicians to evaluate sarcopenia routinely in the follow-up and treatment of older patients with iNPH.

A hand-in-hand phenomenon in older adults: Increased risk of frailty in geriatric outpatients associated with handgrip strength asymmetry and weakness

OBJECTIVES

Handgrip strength (HGS) is accepted as a predictor of overall health status and a biomarker of aging, besides negative health outcomes and mortality. While differences in HGS between the dominant and non-dominant hands are expected, substantial discrepancies may signal impaired muscle function. This study aims to investigate whether handgrip asymmetry can serve as a reliable indicator of frailty in a diverse population of older adults.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

A total of 512 patients aged 65 years and older who were admitted to the geriatric medicine outpatient clinic of a university hospital were enrolled in the study.

METHODS

The Clinical Frailty Scale (CFS) was used to assess the overall level of frailty of the study population. The highest recorded HGS values from the non-dominant and dominant hand were used to calculate the HGS ratio. Those with a HGS ratio of dominant and non-dominant hand <0.90 or >1.10 were defined as HGS asymmetry.

RESULTS

Of the whole study group, 61.1% was female and the mean age was 73.2 ± 6.1 years. The ratio of the participants living with frailty was 57.6% (n = 219). The number of patients with HGS asymmetry was 264 (51.6%), and 48.4% (n = 248) of the study population had symmetric HGS. The normal and symmetric HGS was found in 40.2% of the non-frail group, whereas it was 23.7% in patients living with frailty. Furthermore, the ratio of low and asymmetric HGS was 16.3% in the non-frail group, and 35.0% in the patients living with frailty (p < 0.001). The presence of asymmetric and low HGS increased the risk of frailty three times independently of other confounding factors (OR:3.08; 95% CI:1.48-6.43; p = 0.003).

CONCLUSIONS AND IMPLICATIONS

Identifying HGS asymmetry along with low HGS as potential indicators of frailty may provide clinicians with a clear and quantifiable criterion for assessing older patients.

Fitness, Gray Matter Volume, and Executive Function in Cognitively Normal Older Adults: Cross-Sectional Findings From the AGUEDA Trial

The aim of the study is to investigate the association of cardiorespiratory fitness (CRF) and muscular strength indicators with gray matter volume (GMV) and to study whether fitness-related regions of GMV are associated to executive function (EF) in cognitively normal older adults. Ninety-one cognitively normal older adults (71.69 ± 3.91 years; 57.14% females) participated in this study from the AGUEDA trial. CRF was measured by a 2-km walking test and a 6-min walking test. Muscular strength was measured by handgrip, biceps curl, squats, and isokinetic strength tests. T1-weigthed images were obtained through a magnetic resonance scan. GMV was determined by voxel-based morphometric analysis. Standardized EF tests were performed. CRF did not show any positive association with GMV. Handgrip strength was positively associated with GMV (p < 0.001) in nine regions (β from 0.6 to 0.8 and k from 106 to 1927) and knee extension strength in three regions (β from 0.4 to 0.5 and k from 76 to 2776). Squats strength was negatively associated with GMV (p < 0.001) in two regions (β = -0.3, k = 1102 and k = 152) and the 2-km walking test in one region (β = -0.4, k = 99). Only handgrip strength-related GMV was associated with cognitive flexibility (p = 0.039, β = 0.215) and spatial working memory (p < 0.03, β 0.247-0.317), but not with EF score (p > 0.05). Muscular strength, but no CRF, may be positively related to GMV in cortical and subcortical regions, with implications for specific cognitive domains rather than the overall EF score. Specifically, handgrip strength was the indicator most associated with higher GMV, while squats strength and CRF were negatively related to GMV. ClinicalTrials.gov identifier: NCT05186090.

The association of circulating bioenergetic metabolites with healthy human aging

Aging is an inevitable and gradual decline in several biological functions. Mitochondrial dysfunction is one of the most important hallmarks of aging. In this context, alterations in metabolites associated with mitochondrial dysfunction may serve as a significant biomarker. This study aimed to investigate the existence of a relationship between the key metabolites involved in bioenergetics metabolism and aging. 53 volunteers ranged 20-85 years participated in the study. We tested the association between different tricarboxylic acid (TCA) cycle metabolites, fatty acid metabolism, and amino acid metabolism with age, sex, body composition, and proxy markers of aging such as walking speed, grip strength and chair test. We found that lactic acid negatively correlated with age while several fatty acid metabolites, such as azelaic, sebacic, and linoleic acids, showed positive correlations with age (p < 0.05). Sex-specific trends, such as glycerol, and dodecanoic acid, were also observed for certain metabolites. Furthermore, citric acid levels were found to have a significant association with physical function and body composition measures. Participants with higher citric acid levels displayed improved performance in physical tests and favorable body composition indices. Additionally, fumaric acid and adipic acid showed positive correlations with fat-free body mass, while sebacic acid was negatively associated with measures of fat mass. These findings underscore the importance of understanding the role of circulating bioenergetics metabolites with age, sex variations, and their potential implications in body composition and physical performance.

Association of handgrip strength with health care utilisation among older adults: A longitudinal study in China

Background

Evidence on the association between handgrip strength (HGS) and health care utilisation among Chinese older adults is scarce. In this study, we aimed to investigate the association of HGS with health care utilisation and to identify whether these associations varied by gender.

Methods

The analytic sample of this prospective cohort study included 6007 Chinese older adults (≥60 years) from 2011 to 2018 waves of the China Health and Retirement Longitudinal Study. A handgrip dynamometer was used to measure HGS. We measured health care utilisation by outpatient visits, inpatient visits, and unmet hospitalisation needs. We used covariates-adjusted general estimating equations for the analyses.

Results

Longitudinal results showed that participants with weakness increased the likelihood of outpatient visits (odds ratio (OR) = 1.13; 95% confidence interval (CI) = 1.01-1.27), inpatient visits (OR = 1.51; 95% CI = 1.32-1.73), and unmet hospitalisation needs (OR = 1.44; 95% CI = 1.19-1.79) than their counterparts. Participants with weakness increased the number of outpatient visits (incidence rate ratio (IRR) = 1.29; 95% CI = 1.11-1.51) and the number of inpatient visits (IRR = 1.39; 95% CI = 1.10-1.61). Participants with HGS asymmetry increased the likelihood of unmet hospitalisation needs (OR = 1.19; 95% CI = 1.03-1.43) than their counterparts. The results of the impact of every one-kilogramme (kg) increase in HGS on health care utilisation indicated consistent results. The associations were similarly observed irrespective of gender.

Conclusions

Chinese older adults with weakness or HGS asymmetry used more health care. Interventions for improving muscle strength and correcting strength asymmetry are highly recommended, with the potential to considerably save households and health care systems.

Longitudinal Associations Between Cognition and Grip Strength, Differentiated by Sex and Physical Activity: A Population-Based Study in Older Adults From 17 European Countries

Objectives (1) To investigate longitudinal associations between grip strength (GS) and cognition over 4 years in European older adults, (2) to examine differences in temporal associations between men and women and between levels of physical activity, (3) to explore in each year 2015 and 2019 associations between GS quartiles and cognitive performance, and (4) to explore longitudinal associations between GS quartiles (year 2015) and cognitive performance (year 2019). Methods: 25,281 individuals (14,200 women) from 17 European countries aged ≥50 years responded to waves 6th and 8th of the SHARE project. We analyzed GS, a general cognition index, and physical activity level. Results: Panel analyses revealed a bidirectional relationship over 4 years between GS and cognition, with differences between sex, as well as between participants with moderate-to-vigorous and low physical activity levels. Conclusion: Women and participants with low physical activity were more likely to experience cognitive performance deficits 4 years later.

The relationship between low and asymmetric handgrip strength and low muscle mass: results of a cross-sectional study on health and aging trends in western China

OBJECTIVE

The aim was to determine the relationship between low handgrip strength (HGS) only, asymmetric HGS only, and low HGS combined with asymmetric HGS and low muscle mass in the West China Health and Aging Trends Study (WCHAT) data.

STUDY DESIGN

Individuals aged at least 50 years old were included in this cross-sectional study using WCHAT data. Demographic characteristics, such as age, marital status, education level, ethnicity, and drinking and smoking history, as well as chronic diseases, were recorded for all participants. The HGS of both hands was tested three times using a grip dynanometer with the participant in a standing position with arms extended, before recording the maximum value for both hands. The maximum value referred to values < 28 kg and < 18 kg for males and females, respectively. HGS ratios (non-dominant HGS/dominant HGS) of < 0.90 or > 1.10 suggest asymmetric HGS. The subjects were then allocated to the low HGS, asymmetrical HGS, and combined low and asymmetrical HGS (BOTH group) groups, and those with neither low nor asymmetric HGS (the normal group). The InBody 770 instrument was used for the analysis of muscle mass, with low muscle mass defined as a skeletal muscle mass index (SMI) of < 7.0 kg/m2 or < 5.7 kg/m2 for males and females, respectively. The associations between the different HGS groups and low muscle mass were assessed by logistic regression analysis.

RESULTS

The study included 1748 subjects, of whom 1272 (72.77%) were over the age of 60 years. The numbers of Han, Tibetan, and Qiang were 885 (50.63%), 217 (12.41%), and 579 (33.12%), respectively. A total of 465 individuals (26.60%) were classified as having low muscle mass, while 228 (13.04%), 536 (30.66%), and 125 (7.15%) participants were allocated to the low HGS, asymmetric HGS, and BOTH groups, respectively. The average SMI differed significantly between the normal group and the other groups (normal group vs. asymmetric HGS group vs. low HGS group vs. BOTH group: 6.627 kg/m2 vs. 6.633 kg/m2 vs. 6.492 kg/m2 vs. 5.995 kg/m2, respectively, P < 0.05). In addition, the prevalence of low muscle mass in the normal, asymmetric HGS, low HGS, and BOTH groups increased sequentially, with significant differences (normal group vs. asymmetric HGS group vs. low HGS group vs. BOTH group: 21.5% vs. 22.4% vs. 39.5% vs. 56%, respectively, P = 0.001). Further logistic regression analysis showed that the presence of low HGS (OR = 1.7, 95%CI: 1.203-2.402) and both low and asymmetric HGS (OR = 3.378, 95%CI: 2.173-5.252) were predictive of low muscle mass, with the chance being higher for the latter condition.

CONCLUSION

The findings suggest that although asymmetrical HGS itself does not increase the chances of low muscle mass. When low HGS and a combination of both features (low HGS combined with asymmetric HGS) is present in subjects, the chance of low muscle mass increases.

Weak grip strength among persons with multiple sclerosis having minimal disability is not related to agility or integrity of the corticospinal tract

INTRODUCTION

Mobility impairment is common in multiple sclerosis (MS); however, agility has received less attention. Agility requires strength and neuromuscular coordination to elicit controlled propulsive rapid whole-body movement. Grip strength is a common method to assess whole body force production, but also reflects neuromuscular integrity and global brain health. Impaired agility may be linked to loss of neuromuscular integrity (reflected by grip strength or corticospinal excitability).

OBJECTIVES

We aimed to determine whether grip strength would be associated with agility and transcranial magnetic stimulation (TMS)-based indices of corticospinal excitability and inhibition in persons with MS having low disability. We hypothesized that low grip strength would predict impaired agility and reflect low corticospinal excitability.

METHODS

We recruited 34 persons with relapsing MS (27 females; median [range] age 45.5 [21.0-65.0] years) and mild disability (median [range] Expanded Disability Status Scale 2.0 [0-3.0]), as well as a convenience sample of age- and sex-matched apparently healthy controls. Agility was tested by measuring hop length during bipedal hopping on an instrumented walkway. Grip strength was measured using a calibrated dynamometer. Corticospinal excitability and inhibition were examined using TMS-based motor evoked potential (MEP) and corticospinal silent period (CSP) recruitment curves, respectively.

RESULTS

MS participants had significantly lower grip strength than controls independent of sex. Females with and without MS had weaker grip strength than males. There were no statistically significant sex or group differences in agility. After controlling for sex, weaker grip strength was associated with shorter hop length in controls only (r = 0.645, p < .05). Grip strength did not significantly predict agility in persons with MS, nor was grip strength predicted by corticospinal excitability or inhibition.

CONCLUSIONS

In persons with MS having low disability, grip strength (normalized to body mass) was reduced despite having intact agility and walking performance. Grip strength was not associated with corticospinal excitability or inhibition, suggesting peripheral neuromuscular function, low physical activity or fitness, or other psychosocial factors may be related to weakness. Low grip strength is a putative indicator of early neuromuscular aging in persons with MS having mild disability and normal mobility.

Association between handgrip strength weakness and asymmetry with incident hip fracture among older Chinese adults

BACKGROUND

To evaluate the association between handgrip strength (HGS) weakness and asymmetry with incident hip fracture among older Chinese adults.

METHODS

Data was obtained from the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study (CHARLS). HGS weakness was defined as maximal HGS 〈 28 kg in men and < 18 kg in women. HGS asymmetry was defined as the HGS ratio < 0.9 or 〉 1.1. Participants were categorized into normal HGS, weakness only, asymmetry only, and both weakness and asymmetry. Given the sex differences in HGS, the association between HGS weakness and asymmetry was analyzed by sex using the multivariable logistic regression models.

RESULTS

A total of 4789 participants aged ≥ 60 years old without hip fracture at baseline were included in the final analysis. Over the four-year follow-up, there were 152 (3.17 %) participants having incident hip fractures, of which 69 (2.90 %) were men and 83 (3.45 %) were women. Compared to the normal group, men with both weakness and asymmetry had a significantly higher risk of incident hip fracture in the fully adjusted model (adjusted odds ratio (OR): 2.31, 95 % confidence interval (CI):1.17-4.52). There was no significant association between HGS asymmetry and weakness with hip fracture in women.

CONCLUSIONS

Our findings indicated that among the Chinese population, men with both HGS weakness and asymmetry were associated with increased odds of hip fracture, while no significant association was observed in women.

Pharmacological inhibition of receptor-interacting protein kinase 2 (RIPK2) elicits neuroprotective effects following experimental ischemic stroke

Ischemic stroke induces a debilitating neurological insult, where inflammatory processes contribute greatly to the expansion and growth of the injury. Receptor-interacting protein kinase 2 (RIPK2) is most well-known for its role as the obligate kinase for NOD1/2 pattern recognition receptor signaling and is implicated in the pathology of various inflammatory conditions. Compared to a sham-operated control, ischemic stroke resulted in a dramatic increase in the active, phosphorylated form of RIPK2, indicating that RIPK2 may be implicated in the response to stroke injury. Here, we assessed the effects of pharmacological inhibition of RIPK2 to improve post-stroke outcomes in mice subjected to experimental ischemic stroke. We found that treatment at the onset of reperfusion with a RIPK2 inhibitor, which inhibits the phosphorylation and activation of RIPK2, resulted in marked improvements in post-stroke behavioral outcomes compared to the vehicle-administered group assessed 24 h after stroke. RIPK2 inhibitor-treated mice exhibited dramatic reductions in infarct volume, concurrent with reduced damage to the blood-brain barrier, as evidenced by reduced levels of active matrix metalloproteinase-9 (MMP-9) and leakage of blood-borne albumin in the ipsilateral cortex. To explore the protective mechanism of RIPK2 inhibition, we next pretreated mice with RIPK2 inhibitor or vehicle and examined transcriptomic alterations occurring in the ischemic brain 6 h after stroke. We observed a dramatic reduction in neuroinflammatory markers in the ipsilateral cortex of the inhibitor-treated group while also attaining a comprehensive view of the vast transcriptomic alterations occurring in the brain with inhibitor treatment through bulk RNA-sequencing of the injured cortex. Overall, we provide significant novel evidence that RIPK2 may represent a viable target for post-stroke pharmacotherapy and potentially other neuroinflammatory conditions.

Plasma levels of Neurofilament light chain correlate with handgrip strength and sarcopenia in patients with chronic obstructive pulmonary disease

BACKGROUND

Age-associated muscle decline, termed sarcopenia, is a common systemic effect of chronic obstructive pulmonary disease (COPD). Circulating Neurofilament light chain (NfL) levels reflect neuronal degradation and may be relevant to sarcopenia phenotype. However, such an association in COPD patients remains elusive.

METHODS

We investigated male, 60-76 years old controls (n = 50) and COPD patients (n = 139) for plasma NfL levels in relation to sarcopenia and physical capacity markers. We measured handgrip strength (HGS), body composition, and short physical performance battery (SPPB) to evaluate sarcopenia and physical capacity.

RESULTS

COPD patients had higher plasma NfL and lower HGS and SPPB performance than controls. Plasma NfL levels demonstrated negative associations with HGS and gait speed in COPD patients (all p < 0.05). Further, NfL levels were negatively associated with total SPPB scores in controls and patients with advanced COPD (p < 0.05). Plasma NfL also demonstrated an acceptable accuracy in diagnosing sarcopenia in controls (AUC = 0.757, p < 0.05) and COPD (AUC = 0.806, p < 0.05) patients.

CONCLUSION

Collectively, plasma NfL may be helpful in evaluating sarcopenia phenotype and physical capacity in geriatric patients with COPD.

Enhancing predictive validity of motoric cognitive risk syndrome for incident dementia and all-cause mortality with handgrip strength: insights from a prospective cohort study

Background

This study aimed to assess whether integrating handgrip strength (HGS) into the concept of motoric cognitive risk (MCR) would enhance its predictive validity for incident dementia and all-cause mortality.

Methods

A cohort of 5, 899 adults from the Health and Retirement Study underwent assessments of gait speed, subjective cognitive complaints, and HGS were involved. Over a 10-year follow-up, biennial cognitive tests and mortality data were collected. Cox proportional hazard analyses assessed the predictive power of MCR alone and MCR plus HGS for incident dementia and all-cause mortality.

Results

Patients with MCR and impaired HGS (MCR-HGS) showed the highest adjusted hazard ratios (AHR) for dementia (2.33; 95% CI, 1.49-3.65) and mortality (1.52; 95% CI, 1.07-2.17). Even patients with MCR and normal HGS (MCR-non-HGS) experienced a 1.77-fold increased risk of incident dementia; however, this association was not significant when adjusted for socioeconomic status, lifestyle factors, and medical conditions. Nevertheless, all MCR groups demonstrated increased risks of all-cause mortality. The inclusion of HGS in the MCR models significantly improved predictive discrimination for both incident dementia and all-cause mortality, as indicated by improvements in the C-statistic, integrated discrimination improvement (IDI) and net reclassification indices (NRI).

Conclusion

Our study underscores the incremental predictive value of adding HGS to the MCR concept for estimating risks of adverse health outcomes among older adults. A modified MCR, incorporating HGS, could serve as an effective screening tool during national health examinations for identifying individuals at risk of dementia and mortality.

Hand Grip Force-Time Curve Indicators Evaluated by Dynamometer: A Systematic Review

BACKGROUND

Handgrip strength (HGS) is an indicator of muscular strength, used in the diagnosis of sarcopenia, undernutrition, and physical frailty as well as recovery. Typically, the maximum HGS value is used; however, recent evidence suggests the exploration of new indicators provided based on the force-time curve to achieve a more comprehensive assessment of muscle function. Therefore, the objective was to identify indicators of the HGS profile beyond maximum HGS, based on force-time curves, and to systematize knowledge about their applications to various types of samples, health issues, and physical performance.

METHODS

A systematic review was performed including studies whose participants' HGS was assessed with a digital or adapted dynamometer. The outcome measures were HGS profile indicators calculated from the force-time curve.

RESULTS

a total of 15 studies were included, and the following indicators were identified: grip fatigue, fatigability index, fatigue rate, fatigue resistance, time to 80% maximal voluntary contraction, plateau coefficient of variability, time to maximum value, T-90%, release rate, power factor, grip work, average integrated area, endurance, cycle duration, time between cycles, maximum and minimum force-velocity, rate of grip force, final force, inflection point, integrated area, submaximal control, and response time.

CONCLUSIONS

Various indicators based on the force-time curve can be assessed through digital or adapted dynamometers. Future research should analyze these indicators to understand their implications for muscle function assessment, to standardize evaluation procedures, to identify clinically relevant measures, and to clarify their implications in clinical practice.

Evaluation of Factors Influencing Handgrip Strength Asymmetry in Older Peruvian Adults

BACKGROUND

Sarcopenia is a musculoskeletal disease involving the reduction of muscle mass, strength, and performance. Handgrip strength (HGS) measurements included in frailty assessments are great biomarkers of aging and are related to functional deficits. We assessed the association between potential influencing factors and HGS asymmetry in older Peruvian adults.

METHODS

We used a database of the Peruvian Naval Medical Center "Cirujano Santiago Távara" located in Callao, Peru. All the patients included were ≥60 years old and had an HGS measurement in the dominant and non-dominant hand.

RESULTS

From a total of 1,468 patients, 74.66% had HGS asymmetry. After adjustment, calf circumference weakness (adjusted prevalence ratio [aPR]=1.08; 95% confidence interval [CI], 1.01-1.15), falls risk (aPR = 1.08; 95% CI, 1.02-1.16), and an altered Lawton index (aPR=0.92; 95% CI, 0.84-0.99) were associated with HGS asymmetry.

CONCLUSION

Our findings suggest that HGS asymmetry should be measured along with other geriatric assessments used to evaluate health outcomes in the elderly to enhance health promotion and prevention aimed at preserving muscle strength to curb functional limitations in the elderly.

Age- and sex-related changes in motor functions: a comprehensive assessment and component analysis

Age-related motor impairments often cause caregiver dependency or even hospitalization. However, comprehensive investigations of the different motor abilities and the changes thereof across the adult lifespan remain sparse. We, therefore, extensively assessed essential basic and complex motor functions in 444 healthy adults covering a wide age range (range 21 to 88 years). Basic motor functions, here defined as simple isolated single or repetitive movements in one direction, were assessed by means of maximum grip strength (GS) and maximum finger-tapping frequency (FTF). Complex motor functions, comprising composite sequential movements involving both proximal and distal joints/muscle groups, were evaluated with the Action Research Arm Test (ARAT), the Jebsen-Taylor Hand Function Test (JTT), and the Purdue Pegboard Test. Men achieved higher scores than women concerning GS and FTF, whereas women stacked more pins per time than men during the Purdue Pegboard Test. There was no significant sex effect regarding JTT. We observed a significant but task-specific reduction of basic and complex motor performance scores across the adult lifespan. Linear regression analyses significantly predicted the participants' ages based on motor performance scores (R2 = 0.502). Of note, the ratio between the left- and right-hand performance remained stable across ages for all tests. Principal Component Analysis (PCA) revealed three motor components across all tests that represented dexterity, force, and speed. These components were consistently present in young (21-40 years), middle-aged (41-60 years), and older (61-88 years) adults, as well as in women and men. Based on the three motor components, K-means clustering analysis differentiated high- and low-performing participants across the adult life span. The rich motor data set of 444 healthy participants revealed age- and sex-dependent changes in essential basic and complex motor functions. Notably, the comprehensive assessment allowed for generating robust motor components across the adult lifespan. Our data may serve as a reference for future studies of healthy subjects and patients with motor deficits. Moreover, these findings emphasize the importance of comprehensively assessing different motor functions, including dexterity, force, and speed, to characterize human motor abilities and their age-related decline.

Microstructural neural correlates of maximal grip strength in autistic children: the role of the cortico-cerebellar network and attention-deficit/hyperactivity disorder features

Introduction

Maximal grip strength, a measure of how much force a person's hand can generate when squeezing an object, may be an effective method for understanding potential neurobiological differences during motor tasks. Grip strength in autistic individuals may be of particular interest due to its unique developmental trajectory. While autism-specific differences in grip-brain relationships have been found in adult populations, it is possible that such differences in grip-brain relationships may be present at earlier ages when grip strength is behaviorally similar in autistic and non-autistic groups. Further, such neural differences may lead to the later emergence of diagnostic-group grip differences in adolescence. The present study sought to examine this possibility, while also examining if grip strength could elucidate the neuro-motor sources of phenotypic heterogeneity commonly observed within autism.

Methods

Using high resolution, multi-shell diffusion, and quantitative R1 relaxometry imaging, this study examined how variations in key sensorimotor-related white matter pathways of the proprioception input, lateral grasping, cortico-cerebellar, and corticospinal networks were associated with individual variations in grip strength in 68 autistic children and 70 non-autistic (neurotypical) children (6-11 years-old).

Results

In both groups, results indicated that stronger grip strength was associated with higher proprioceptive input, lateral grasping, and corticospinal (but not cortico-cerebellar modification) fractional anisotropy and R1, indirect measures concordant with stronger microstructural coherence and increased myelination. Diagnostic group differences in these grip-brain relationships were not observed, but the autistic group exhibited more variability particularly in the cortico-cerebellar modification indices. An examination into the variability within the autistic group revealed that attention-deficit/hyperactivity disorder (ADHD) features moderated the relationships between grip strength and both fractional anisotropy and R1 relaxometry in the premotor-primary motor tract of the lateral grasping network and the cortico-cerebellar network tracts. Specifically, in autistic children with elevated ADHD features (60% of the autistic group) stronger grip strength was related to higher fractional anisotropy and R1 of the cerebellar modification network (stronger microstructural coherence and more myelin), whereas the opposite relationship was observed in autistic children with reduced ADHD features.

Discussion

Together, this work suggests that while the foundational elements of grip strength are similar across school-aged autistic and non-autistic children, neural mechanisms of grip strength within autistic children may additionally depend on the presence of ADHD features. Specifically, stronger, more coherent connections of the cerebellar modification network, which is thought to play a role in refining and optimizing motor commands, may lead to stronger grip in children with more ADHD features, weaker grip in children with fewer ADHD features, and no difference in grip in non-autistic children. While future research is needed to understand if these findings extend to other motor tasks beyond grip strength, these results have implications for understanding the biological basis of neuromotor control in autistic children and emphasize the importance of assessing co-occurring conditions when evaluating brain-behavior relationships in autism.

Longitudinal trajectories of handgrip strength and their association with motoric cognitive risk syndrome in older adults

BACKGROUND

To identify heterogeneous developmental trajectories of handgrip strength (HGS) in Chinese older adults and to explore the relationship between different developmental trajectories and motoric cognitive risk syndrome (MCR).

METHODS

We used three waves of longitudinal data from the China Health and Retirement Longitudinal Study from 2011 to 2015, which involved 3773 older adults. Growth mixture modeling (GMM) was used to estimate trajectory classes for HGS, followed by binary logistic regression to explore the association between trajectory classes and MCR.

RESULTS

GMM analyses extracted four distinct trajectories of HGS: low level-declining group (16.0 %), upper middle level group (30.9 %), high level-steady group (9.5 %), and lower middle level group (43.6 %). In addition, we found that even after adjusting for important covariates, the odds of MCR prevalence were lower in the medium level-high group, high level-steady group, and medium level-low group compared with the low level-declining group.

CONCLUSION

Appreciable heterogeneity in HGS among older people in China was revealed. Only 9.5 % of older people with HGS in the high level-steady group. And poorer grip strength levels mean a higher risk of MCR. Therefore, interventions should be taken to maintain muscle mass and thus prevent MCR in older adults.

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.