Gait speed, body composition, and dementia. The EPIDOS-Toulouse cohort

Early detection of diseases causing dementia using digital navigation and gait measures: A systematic review of evidence

Wearable digital technologies capable of measuring everyday behaviors could improve the early detection of dementia-causing diseases. We conducted two systematic reviews following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines to establish the evidence base for measuring navigation and gait, two everyday behaviors affected early in AD and non-AD disorders and not adequately measured in current practice. PubMed and Web of Science databases were searched for studies on asymptomatic and early-stage symptomatic individuals at risk of dementia, with the Newcastle-Ottawa Scale used to assess bias and evaluate methodological quality. Of 316 navigation and 2086 gait records identified, 27 and 83, respectively, were included in the final sample. We highlight several measures that may identify at-risk individuals, whose quantifiability with different devices mitigates the risk of future technological obsolescence. Beyond navigation and gait, this review also provides the framework for evaluating the evidence base for future digital measures of behaviors considered for early disease detection.

Association between sarcopenia and cognitive function in older Chinese adults: Evidence from the China health and retirement longitudinal study

Background

Sarcopenia and cognitive impairment are the most common causes of disability in the aging population. The potential role of sarcopenia in the development of cognitive impairment remains poorly understood. A cross-sectional analysis was performed using nationally representative data to evaluate associations between sarcopenia and cognition in China.

Methods

We included 2,391 participants (35.63% female) who were at least 60 years of age in 2015 from the China Health and Retirement Longitudinal Study (CHARLS). Muscle strength, appendicular skeletal mass (ASM), and physical performance measurements, were measured to diagnose sarcopenia according to the Asian Working Group for Sarcopenia 2019 (AWGS2019). Cognitive function was assessed by 10 items in the Telephone Interview for Cognitive Status (TICS-10), delayed word recall, and graph drawing. Based on cognitive score tertiles, data were divided into three groups. Multiple linear and logistic regression models were used to assess the relationship between sarcopenia and cognition.

Results

The prevalence of possible sarcopenia was 27.16% for men and 27.46% for women. Cognitive decline was significantly associated with sarcopenia status (β = -0.88, p < 0.001) and negatively associated with components of sarcopenia in male group. The results remained consistent in male after further adjusting for creatinine, uric acid, blood sugar, etc. Low cognitive function in female was only associated with low muscle strength (β = -0.85, p = 0.02). In addition, participants with possible sarcopenia had greater risk of cognitive decline than those without sarcopenia (OR = 1.41; 95% CI: 1.06-1.87). However, the same association was not significant in female group.

Conclusion

We suggest that sarcopenia might be associated with cognition function, with possible sarcopenia being significantly associated with higher cognition risk in China population, which providing a further rationale for timely recognition and management of sarcopenia.

Gait in cerebral small vessel disease, pre-dementia, and dementia: A systematic review

BACKGROUND

The interrelationships between gait, cerebral small vessel disease (CSVD), and cognitive impairments in aging are not well-understood-despite their common co-occurrence.

OBJECTIVE

To systematically review studies of gait impairment in CSVD, pre-dementia, and dementia, and to identify key gaps for future research and novel pathways toward intervention.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided search strategy was implemented in PubMed to identify relevant studies. Potential articles (n = 263) published prior to 1 December 2021 were screened by two reviewers. Studies with sample sizes >20 and including some adults over > 65 years (n = 202) were included.

RESULTS

The key findings were that (1) adverse gait and cognitive outcomes were associated with several (rather than select) CSVD pathologies distributed across the brain, and (2) poor gait and CSVD pathologies were more strongly associated with dementia with a vascular, rather than an Alzheimer's disease-related, cause.

DISCUSSION

A better understanding of the interrelationships between gait performance in CSVD, pre-dementia, and dementia requires studies examining (1) comprehensive patterns in the clinical manifestations of CSVD, (2) racially/ethnically diverse samples, (3) samples followed for extended periods of time or across the adult life span, (4) non-traditional CSVD neuroimaging markers (e.g. resting-state functional magnetic resonance imaging (fMRI)), and (5) continuous (e.g. wearable sensors) and complex (e.g. dual-task) walking performance.

Predictive Validity of Different Walking Measures to Identify the Incident Long-Term Care Needs in Older Adults

OBJECTIVES

A comfortable walking speed is a suitable measurement of functional status in older adults. In addition to assessing their comfortable walking speed, two complex walking tests were administered to a cohort of older people, assuming that these tests would be a more sensitive predictor of the incident long-term care needs than comfortable walking speed.

DESIGN

A prospective observational study was conducted to collect data.

SETTING AND PARTICIPANTS

Among the initial 5,563 community-dwelling independent older adults (aged ≥ 65 years), 935 were excluded and the data of 4,628 (mean age, 73.9 ± 5.5 years, 65-94 years; 2,052 men, 2,576 women) older adults were finally analyzed.

METHODS

Three walking tasks were administered: comfortable, complicated balance, and Go-stop walking. Complicated balance walking was measured under comfortable walking conditions, with participants having to walk with their hands crossed at the shoulder joint at 90°. For the Go-stop walking test, the time taken to walk 2 meters was measured using a stopwatch. For two years following baseline assessments, participants received monthly follow-ups for incident certification of the need for care under the long-term care insurance (LTCI) system.

RESULTS

Low performance in comfortable, complicated balance, and Go-stop walking were 29.8%, 37.7%, and 35.1%, respectively. During the 24-month follow-up period, 246 participants (5.3%) required LTCI certification. The Youden Index was used to determine the cut-points of the incident long-term care needs in the comfortable, complicated balance, and Go-stop walking conditions, which were 1.055 m/s, 0.936 m/s, and 3.205 seconds, respectively. Participants classified as exhibiting low performance included 1,381 (29.8%) under comfortable walking, 1,746 (37.7%) under complicated balance walking, and 1,623 (35.1%) under the Go-stop walking tests. The C-indices of the comfortable, complicated balance, and Go-stop walking tests were 0.72 (95% confidence interval (CI) 0.69-0.76), 0.71 (95% CI 0.67-0.74), and 0.65 (95% CI 0.61-0.69), respectively. Cox proportional hazards regression model revealed significant relationships between the incident long-term care needs and the comfortable (hazard ratio (HR) 2.14, 95% CI 1.62-2.84), complicated balance (1.81, 1.36-2.41), and Go-stop (1.46, 1.12-1.91) walking conditions.

CONCLUSIONS AND IMPLICATIONS

The findings suggest that slow walking speed has a considerably greater impact on the incident long-term care needs in older adults. However, the complex walking task did not improve the predictive performance. Comfortable walking speed tests, which can easily be measured to predict the future incident long-term care needs, are effective tools in community health promotion and primary care.

Decline in skeletal muscle mass is associated with cognitive decline in type 2 diabetes mellitus

AIMS

To examine the longitudinal association between skeletal muscle mass (SMM) loss and cognitive decline over time in type 2 diabetes mellitus (T2DM).

METHODS

We conducted a prospective cohort study of 453 patients from SMART2D cohort with follow-up intervals of 1.6 to 6.4 years. Baseline and follow-up measurements included bio-impedance analysis (BIA) measure of skeletal muscle mass index (SMI) and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) measure of cognitive function. We examined the association between annual rate of SMI and RBANS scores using linear regression, adjusting for demographics, education, depression, clinical co-variables and presence of apolipoprotein E4 (APOE) _Ɛ4 allele.

RESULTS

The mean age of participants was 60.3 ± 7.4 years. Compared to patients with Tertile 1 SMI change, the group with greater SMI decline (Tertile 3 SMI change) experienced 0.30 decline in RBANS total score (95%CI -0.57 to -0.03; p = 0.030) in the adjusted analysis. RBANS scores for subdomains in immediate memory and visuo-spatial/construction were lower in Tertile 3 SMI change group with corresponding coefficients -0.54 (95%CI -1.01 to -0.06; p = 0.026), and -0.71 (95%CI -1.30 to -0.12; p = 0.019) respectively.

CONCLUSION

In patients with T2DM, BIA measure of muscle mass loss over time was independently associated with cognitive decline globally and in the domains of memory and visuo-spatial/construction.

Association of life course adiposity with risk of incident dementia: a prospective cohort study of 322,336 participants

Cohort studies report inconsistent associations between body mass index (BMI) and all-cause incident dementia. Furthermore, evidence on fat distribution and body composition measures are scarce and few studies estimated the association between early life adiposity and dementia risk. Here, we included 322,336 participants from UK biobank to investigate the longitudinal association between life course adiposity and risk of all-cause incident dementia and to explore the underlying mechanisms driven by metabolites, inflammatory cells and brain structures. Among the 322,336 individuals (mean (SD) age, 62.24 (5.41) years; 53.9% women) in the study, during a median 8.74 years of follow-up, 5083 all-cause incident dementia events occurred. The risk of dementia was 22% higher with plumper childhood body size (p < 0.001). A strong U-shaped association was observed between adult BMI and dementia. More fat and less fat-free mass distribution on arms were associated with a higher risk of dementia. Interestingly, similar U-shaped associations were found between BMI and four metabolites (i.e., 3-hydroxybutrate, acetone, citrate and polyunsaturated fatty acids), four inflammatory cells (i.e., neutrophil, lymphocyte, monocyte and leukocyte) and abnormalities in brain structure that were also related to dementia. The findings that adiposity is associated with metabolites, inflammatory cells and abnormalities in brain structure that were related to dementia risk might provide clues to underlying biological mechanisms. Interventions to prevent dementia should begin early in life and include not only BMI control but fat distribution and body composition.

Gender differentiated score on the Falls Efficacy Scale International (FES-I Brazil) to assess self-efficacy in falls in community-dwelling older adults

BACKGROUND

Since fear of falling is associated with a history of falls and is more prevalent in women, it is important to define cut-off points differentiated between genders on the Falls Efficacy Scale International Brazil (FES-I Brazil) to implement early prevention and/or rehabilitation strategies.

AIMS

To determine cut-off points on the FES-I Brazil differentiated between genders which discriminate falls and verify their association with the history of falls.

METHODS

This was a cross-sectional study including 306 community-dwelling older adults. Fear of falling score from the FES-I Brazil was the independent variable and the outcome was the history of falls in the last 12 months. The cut-off points differentiated between genders were established according to sensitivity and specificity values evaluated by the Receiver Operating Characteristic Curves (ROC). The multivariable logistic regression was used to verify the association between fear of falling and history of falls.

RESULTS

The cut-off points on the FES-I Brazil to discriminate falls were > 25 points [AUC: 0.67 (95% CI 0.59-0.73)] for women, and > 19 points [AUC: 0.66 (95% CI 0.57-0.74) for men, suggesting that women present a greater fear of falling than men, due to the higher cut-off point found for women. Women and men with fear of falling, respectively, had 2.14 (95% CI 1.11-4.13) and 2.62 (95% CI 1.10-6.85) higher odds of suffering falls compared to those without this condition.

CONCLUSIONS

The FES-I can be used to discriminate falls in the elderly and shows that women have a higher cut-off point than men on the scale.

Physical activity as a protective factor for dementia and Alzheimer's disease: systematic review, meta-analysis and quality assessment of cohort and case-control studies

Objective

Physical activity (PA) is associated with a decreased incidence of dementia, but much of the evidence comes from short follow-ups prone to reverse causation. This meta-analysis investigates the effect of study length on the association.

Design

A systematic review and meta-analysis. Pooled effect sizes, dose–response analysis and funnel plots were used to synthesise the results.

Data sources

CINAHL (last search 19 October 2021), PsycInfo, Scopus, PubMed, Web of Science (21 October 2021) and SPORTDiscus (26 October 2021).

Eligibility criteria

Studies of adults with a prospective follow-up of at least 1 year, a valid cognitive measure or cohort in mid-life at baseline and an estimate of the association between baseline PA and follow-up all-cause dementia, Alzheimer’s disease or vascular dementia were included (n=58).

Results

PA was associated with a decreased risk of all-cause dementia (pooled relative risk 0.80, 95% CI 0.77 to 0.84, n=257 983), Alzheimer’s disease (0.86, 95% CI 0.80 to 0.93, n=128 261) and vascular dementia (0.79, 95% CI 0.66 to 0.95, n=33 870), even in longer follow-ups (≥20 years) for all-cause dementia and Alzheimer’s disease. Neither baseline age, follow-up length nor study quality significantly moderated the associations. Dose–response meta-analyses revealed significant linear, spline and quadratic trends within estimates for all-cause dementia incidence, but only a significant spline trend for Alzheimer’s disease. Funnel plots showed possible publication bias for all-cause dementia and Alzheimer’s disease.

Conclusion

PA was associated with lower incidence of all-cause dementia and Alzheimer’s disease, even in longer follow-ups, supporting PA as a modifiable protective lifestyle factor, even after reducing the effects of reverse causation.

Differential associations of regional cerebellar volume with gait speed and working memory

The relationship between gait speed and working memory is well-understood in older adults. However, it remains to be determined whether this relationship also exists in younger adults; and there is little known regarding the possible neural mechanism underlying the association between gait speed and working memory. The aims of this study are to determine if there is: (1) an association between gait speed and working memory performance; and (2) a mediating role of cerebellar subregion volume in the correlation between gait speed and working memory in healthy younger adults. 1054 younger adults (28.7 ± 3.6 years) from the Human Connectome Project were included in the analyses. A four-meter gait test was used to assess gait speed. The 2-back task was used to measure working memory performance [accuracy and response time (RT)]. T1-weighted structural MRI data (obtained using Siemens 3 T MRI scanner) was used to assess cerebellar subregion volumes. Linear regression and mediation analysis were used to examine the relationships between the variables after controlling for age, sex, and education. There was no association between gait speed and 2-back working memory performance in younger adults. Greater Crus I and whole cerebellar volumes were associated with better 2-back working memory accuracy. Greater VIIIa volume was associated with faster gait speed. Greater Crus 1 and VIIIa volumes were also associated with higher fluid cognition. The present study suggests that specific subregions of the cerebellar volumes are distinctively associated with gait speed and working memory performance in healthy younger adults.

Bone and Lean Mass Loss and Cognitive Impairment for Healthy Elder Adults: Analysis of the Nutrition and Health Survey in Taiwan 2013-2016 and a Validation Study With Structural Equation Modeling

Purpose: Bone and lean mass loss and cognitive impairment are prevalent in elder adults and have been hypothesized to share a potential link. Methods: This nationwide cross-sectional study systemically sampled elder adults aged ≥65 years and conducted the door-to-door survey. The causal diagrams help to decide which covariates were included in the generalized linear mixed models (GLMMs). The structural equation modeling (SEM) was performed for the validation. Results: A total of 535 participants were enrolled and categorized into the normal (67.3%), mild cognitive impairment (18.3%), and dementia groups (14.4%). With increasing in the severity of cognitive impairment, the bone marrow density and lean mass consistently showed the trend of decreasing values. In the GLMMs, a significant association existed between the decrease of the bone mineral density (BMD) and the Mini-Mental State Examination (MMSE) (β = 5.819 scores per g/cm² decrease, p = 0.0305) with adjustment of the age, sex, and physical activity. The SEM models confirmed that the MMSE was significantly and directly predicted by the age (β = 0.1363, p = 0.0003) and BMD (β = 0.1251, p = 0.0006) independently and indirectly predicted by lean mass (β = 0.1138, p = 0.0003) through the bone density path. Conclusion: In conclusion, an independent association between bone loss and cognitive impairment was existed rather than the confounding effect and the decrease of lean mass indirectly contributed to cognitive impairment by influencing the bone density.

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

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

Sarcopenia and Mild Cognitive Impairment in Older Adults from Six Low- and Middle-Income Countries

BACKGROUND

Little is known about the relationship between sarcopenia and mild cognitive impairment (MCI) in low- and middle-income countries (LMICs).

OBJECTIVE

This study aimed to investigate this association among community-dwelling adults aged≥65 years from six LMICs.

METHODS

Cross-sectional, nationally representative data from the Study on Global Ageing and Adult Health (SAGE) were analyzed. These data were obtained in China, Ghana, India, Mexico, Russia, and South Africa in 2007-2010. Participants were considered to have sarcopenia if they had low skeletal muscle mass (i.e., lower skeletal mass index) and a weak handgrip strength. MCI was defined using the National Institute on Aging-Alzheimer's Association criteria. Multivariable logistic regression analysis was conducted to assess associations.

RESULTS

The final analytical sample consisted of 12,912 individuals aged≥65 years with preservation in functional abilities without stroke (mean [standard deviation] age 72.2 [10.8] years; 45.2% males). The overall prevalence of sarcopenia and MCI were 11.3% and 18.1%, respectively. After adjusting for potential confounders, there was a positive association between sarcopenia and MCI in all countries (i.e., odds ratio [OR] > 1) with the exception of South Africa, and the overall estimate was OR = 1.60 (95% confidence interval [CI] = 1.32-1.93) with a low level of between-country heterogeneity (I2 = 0.0%).

CONCLUSION

There was a positive association between sarcopenia and MCI in this sample of older adults living in LMICs. Causality should be assessed in future longitudinal research, while the utility of sarcopenia as a marker of MCI should also be investigated.

Identification of Disability Risk in Addition to Slow Walking Speed in Older Adults

INTRODUCTION

A cutoff speed of 1.0 m/s for walking at a comfortable pace is critical for predicting future functional decline. However, some older adults with walking speeds below the cutoff point maintain an independent living. We aimed to identify specific predictors of disability development in older adults with slow walking speeds in contrast to those with a normal walking speed.

METHODS

This prospective cohort study on 12,046 community-dwelling independent Japanese older adults (mean age, 73.6 ± 5.4 years) was conducted between 2011 and 2015. Participants were classified into slow walking speed (comfortable walking speed slower than 1.0 m/s) and normal walking speed (speed of 1.0 m/s or faster) groups and followed up to assess disability incidence for 24 months after baseline assessments. Cox proportional hazards regression models were used to identify predictors of disability development in the slow and normal walking groups.

RESULTS

Overall, 26.8% of participants had a slow walking speed. At follow-up, 17.3% and 5.1% of participants in the slow and normal walking groups, respectively, developed disability (p < 0.01). Cox regression models revealed that age (hazard ratio 1.07, 95% confidence interval 1.05-1.09), walking speed (0.12, 0.07-0.22), grip strength (0.97, 0.95-0.99), Parkinson's disease (4.65, 2.59-8.33), word list memory-immediate recognition score (0.90, 0.85-0.97), word list memory-delayed recall score (0.94, 0.89-1.00), Symbol Digit Substitution Test (SDST) score (0.98, 0.96-0.99), and 15-item Geriatric Depression Scale (GDS) score (1.04, 1.01-1.07) were significantly associated with disability incidence in the slow walking group. In the normal walking group, age, grip strength, depression, diabetes, cognition, GDS score, and reduced participation in outdoor activity were significantly associated with disability incidence; however, there was no significant association with walking speed.

CONCLUSIONS

Decreased walking speeds have considerably greater impact on disability development in older adults with a slow walking speed than in those with a normal walking speed. Health-care providers should explore modifiable factors for reducing walking speed; they should also encourage improvement of risk factors such as muscle weakness and depression to reduce disability risk in older adults with slow walking speeds.

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

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

Skeletal Muscle Health and Cognitive Function: A Narrative Review

Sarcopenia is the loss of skeletal muscle mass and function with advancing age. It involves both complex genetic and modifiable risk factors, such as lack of exercise, malnutrition and reduced neurological drive. Cognitive decline refers to diminished or impaired mental and/or intellectual functioning. Contracting skeletal muscle is a major source of neurotrophic factors, including brain-derived neurotrophic factor, which regulate synapses in the brain. Furthermore, skeletal muscle activity has important immune and redox effects that modify brain function and reduce muscle catabolism. The identification of common risk factors and underlying mechanisms for sarcopenia and cognition may allow the development of targeted interventions that slow or reverse sarcopenia and also certain forms of cognitive decline. However, the links between cognition and skeletal muscle have not been elucidated fully. This review provides a critical appraisal of the literature on the relationship between skeletal muscle health and cognition. The literature suggests that sarcopenia and cognitive decline share pathophysiological pathways. Ageing plays a role in both skeletal muscle deterioration and cognitive decline. Furthermore, lifestyle risk factors, such as physical inactivity, poor diet and smoking, are common to both disorders, so their potential role in the muscle-brain relationship warrants investigation.

Development and Validation of Person-Centered Cut-Points for the Figure-of-8-Walk Test of Mobility in Community-Dwelling Older Adults

BACKGROUND

The Figure-of-8-Walk test (F8WT) is a performance measure of the motor skill of walking. Unlike walking speed over a straight path, it captures curved path walking, which is essential to real-world activity, but meaningful cut-points have yet to be developed for the F8WT.

METHODS

A secondary analysis of 421 community-dwelling older adults (mean age 80.7 ± 7.8), who participated in a community-based exercise clinical trial, was performed. Area under receiver operating characteristic curves (AUROCC) were calculated using baseline data, with F8WT performance discriminating different self-reported global mobility and balance dichotomies. Cut-points for the F8WT were chosen to optimize sensitivity and specificity. For validation, F8WT cut-points were applied to postintervention F8WT data. Participants were called monthly for 12 months after intervention completion to record self-reported incident falls, emergency department visits, and hospitalizations; risks of the outcomes were compared between those who performed well and poorly on the F8WT.

RESULTS

F8WT performance times of ≤9.09 seconds and ≤9.27 seconds can discriminate those with excellent (sensitivity = 0.647; specificity = 0.654) and excellent/very good global mobility (sensitivity = 0.649; specificity = 0.648), respectively. A total number of steps ≤17 on the F8WT can discriminate those with excellent/very good/good global balance (sensitivity = 0.646; specificity = 0.608). Compared to those who performed poorly, those who performed well had a lower incidence of negative outcomes: F8WT time ≤9.09 seconds = 46%-59% lower; F8WT time ≤9.27 seconds = 46%-56% lower; F8WT steps ≤17 = 44%-50% lower.

CONCLUSIONS

Clinicians may consider these preliminary cut-points to aid in their clinical decision making, but further study is needed for definitive recommendations.

Lifetime Duration of Exposure to Biomechanical Factors at Work as a Mediator of the Relationship Between Socioeconomic Position and Walking Speed

The study aimed to assess the proportion mediated by the duration of exposure to ergonomic factors at work on the relationship between socioeconomic position (SEP) and low walking speed. This cross-sectional study was performed on data collected at baseline on 19,704 men and 20,273 women 45-70 years old, currently or previously employed, enrolled in the Constances cohort. SEP was assigned through current or last occupation, categorized in three classes, based on the European Socioeconomic Classification. Walking speed was assessed through one measurement of normal walking for 3 m and dichotomized at the lowest quintile of the sex- and age- (5-year) specific distribution. Self-reported workplace exposure throughout working life to repetitive work, intense physical work, and lifting/carrying heavy loads was used to assess the duration of exposure to each factor, categorized in four classes. Through Poisson regression models, adjusted for BMI, smoking, alcohol intake, hypertension, physical activity, diabetes, cardiovascular diseases, and a cognitive score, the attenuation in the prevalence ratio (PR) of low walking speed by SEP produced by the inclusion of duration of exposure to each factor was evaluated. The mediating effect of work ergonomic exposures on the relationship between SEP and low walking speed was assessed using the weighted method by Vanderweele. In the fully adjusted model without ergonomic exposures, both men and women in the middle and the lowest SEP had a significantly increased risk of low walking speed compared with those in the highest SEP (men: PR = 1.30 and PR = 1.46, respectively; women: PR = 1.24 and PR = 1.45, respectively). The inclusion in separate regression models of exposure duration to repetitive work, intense physical work, and handling of heavy loads produced modest risk attenuations in both men and women, all smaller or around 10%. Mediation analysis revealed in both sexes significant mediation effects for most ergonomic exposures considered, although also with low mediation effects. Significant differences in walking speed by SEP were observed in this large sample, but the proportion of such differences explained by the duration of exposure to ergonomic factors at work was low using either the risk attenuation or the mediation analysis methods.

Associations of body composition with incident dementia in older adults: Cardiovascular Health Study-Cognition Study

INTRODUCTION

A body of literature reported associations between late-life general adiposity measures (eg, body mass index) and dementia. Little is known about the association of late-life body composition with dementia risk.

METHODS

We determined this association among cognitively normal participants from the Cardiovascular Health Study- Cognition Study. Body composition was assessed by dual-energy x-ray absorptiometry in 1994-1995. Dementia was ascertained at annual follow-up from 1998-1999 to 2013. Associations of body composition with incident dementia were assessed by the Fine-Gray model.

RESULT

Among 344 participants (mean age 78, 62.2% women), body composition was significantly different between men and women, despite similar body mass indexes (BMIs). Increased dementia risk was significantly associated with lower lean mass in men and marginally with low appendicular lean mass in women.

DISCUSSION

Decreased lean mass was an indicator of increased dementia risk in older adults. Studies should test whether preventing lean mass loss in older adults reduces dementia risk.

Muscle strength and gait speed rather than lean mass are better indicators for poor cognitive function in older men

We aimed to examine muscle strength, function and mass in relation to cognition in older men. This cross-sectional data-set included 292 men aged ≥60 yr. Handgrip strength (kg) was measured by dynamometry, gait speed by 4-metre walk (m/s) and appendicular lean mass (kg) by dual-energy x-ray absorptiometry. Cognition was assessed across four domains: psychomotor function, attention, visual learning and working memory. Composite scores for overall cognition were calculated. Bivariate analyses indicated that handgrip strength and gait speed were positively associated with cognitive function. After accounting for confounders, positive associations between individual muscle (or physical) measures and cognitive performance were sustained for handgrip strength and psychomotor function, gait speed and psychomotor function, gait speed and attention, handgrip strength and overall cognition, and gait speed and overall cognition. In multivariable models, handgrip strength and gait speed independently predicted psychomotor function and overall cognition. No associations were detected between lean mass and cognition after adjusting for confounders. Thus, low muscle strength and slower gait speed, rather than low lean mass, were associated with poor cognition in older men.

Motoric cognitive risk syndrome: Integration of two early harbingers of dementia in older adults

Dementia is characterized by a long preclinical phase that may last years to decades before the onset of mild cognitive impairment. Slow gait speed and subjective memory complaint commonly co-occur during this preclinical phase, and each is a strong independent predictor of cognitive decline and dementia. Motoric cognitive risk (MCR) syndrome is a pre-dementia syndrome that combines these two early harbingers of dementia. The risk of cognitive decline or dementia is stronger for MCR than for either slow gait speed or subjective memory complaint alone. Slow gait speed and subjective memory complaint have several common risk factors: cardiovascular disease, diabetes mellitus, abnormal cortisol profiles, low vitamin D levels, brain atrophy with decreased hippocampal volume, and increased deposition of beta-amyloid in the brain. The underlying pathogenesis of MCR remains poorly understood. Metabolomics and proteomics have great potential to provide new insights into biological pathways involved in MCR during the long preclinical phase preceding dementia.

Association between Lower Extremity Skeletal Muscle Mass and Impaired Cognitive Function in Type 2 Diabetes

Lower extremity skeletal muscle mass (LESM) in Type 2 Diabetes (T2D) has been linked to adverse clinical events, but it is not known whether it is associated with cognitive difficulties. We conducted a cross-sectional study on 1,235 people (mean age 61.4 ± 8.0 years) with T2D under primary and secondary care in Singapore. Bioelectrical impedance analyses (BIA) measures of upper extremity skeletal muscle mass (UESM), LESM and appendicular skeletal muscle index (SMI) were related to the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) measures of cognition, in multiple linear regression. In multivariable models, tertile 1 LESM (b = −2.62 (−3.92 to −1.32)) and tertile 2 LESM (b = −1.73 (−2.73 to −0.73)), referenced to tertile 3) were significantly associated with decreased RBANS total score. Significant associations of LESM with cognitive domain performances were observed for tertile 1 (b = −3.75 (−5.98 to −1.52)) and tertile 2 (b = −1.98 (−3.69 to −0.27)) with immediate memory, and for tertile 1 (b = −3.05 (−4.86 to −1.24)) and tertile 2 (b = −1.87 (−3.25 to −0.48)) with delayed memory, and for tertile 1 (b = −2.99 (−5.30 to −0.68)) with visuospatial/constructional ability. Tertile 1 SMI (b = −1.94 (−3.79 to −0.08) and tertile 2 SMI (b = −1.75 (−3.14 to −0.37)) were also associated with delayed memory. There were no associations between UESM with cognitive performance. Lower LESM may be a useful marker of possible co-occuring cognitive dysfunction.

Sarcopenia and cognitive impairment: A systematic review and meta-analysis

BACKGROUND

Sarcopenia and cognitive impairment are two of the most prevalent causes of disability in the aging population. Despite the vast amount of research that has been done to quantify the association between these two conditions, extensive systematic reviews and meta-analyses remain limited.

METHODS

We performed a systematic review using the PubMed, EMBASE, Scopus, and Google Scholar databases. Sarcopenia was defined as the loss of skeletal muscle mass and muscle function, as measured by muscle strength or performance. Cognitive impairment was diagnosed by validated cognitive or neuropsychological tests.

RESULTS

We identified 303 potentially relevant articles in the initial search. Observational studies quantifying a relationship between sarcopenia and cognitive impairment were selected. Information was extracted from 15 studies, and random-effects models were used for the meta-analysis. The pooled odds ratios for cognitive impairment for patients with sarcopenia compared with patients without sarcopenia were 2.85 (95% confidence interval: 2.19-3.72) in the unadjusted analysis and 2.25 (95% confidence interval: 1.70-2.97) in the adjusted meta-analysis. These results remained constant in subgroup analyses by study population, study region, the definition of sarcopenia, and cognitive impairment. Although half of the studies (8 out of 15) were of fair quality, we conducted a sensitivity analysis to exclude studies with fair quality and obtained similar results.

CONCLUSIONS

Sarcopenia is associated with an increased risk of cognitive impairment independent of study population, the definition of sarcopenia, and cognitive impairment. This suggests the importance of the early recognition of sarcopenia for the prevention of cognitive impairment in clinical practice.

The impact of muscle function, muscle mass and sarcopenia on independent ageing in very old Swedish men

Background

Preserved functions of daily life and cognition are cornerstones of independent aging, which is crucial for maintaining a high quality of life. The aim of this study was to examine the impact of sarcopenia, and its underlying components, on independent ageing in a cohort study of very old men.

Methods

The presence of sarcopenia and independent ageing at a mean age of 87 was investigated in 287 men from the Uppsala Longitudinal Study of Adult Men. Five years later 127 men were re-evaluated for independent ageing. Sarcopenia was defined by two different definitions from the European Working Group on Sarcopenia in Older People. In the first definition sarcopenia was defined as skeletal muscle index < 7.26 kg/m² and either gait speed ≤0.8 m/s or hand grip strength < 30 kg. In the later up-dated definition, HGS < 27 kg and/or chair stand test > 15 s defines probable sarcopenia, which is confirmed by SMI < 7.0 kg/m². Independent ageing was defined as a Mini-Mental State Examination score of ≥25 points, absence of diagnosed dementia, community-dwelling, independency in personal care and ability to walk outdoors alone.

Results

Sarcopenia at baseline was observed in 21% (60/287) and 20% (58/287), respectively, due to definition. The prevalence of independent ageing was 83% (239/288) at baseline and 69% (87/127) five years later. None of the sarcopenia diagnoses were associated with independent ageing. In contrast, gait speed was both in cross-sectional (odds ratio (OR) per one standard deviation increase 2.15, 95% confidence interval (CI) 1.47–3.15), and in longitudinal multivariate analyses (OR 1.84, 95% CI 1.19–2.82). In the cross-sectional analysis also higher hand grip strength was associated with independent ageing (OR 1.58, 95% CI 1.12–2.22), while a slower chair stand test was inversely associated (OR 0.61, 95% CI 0.43–0.86). Muscle mass; i.e. skeletal muscle index, was not associated with independent ageing.

Conclusions

For very old men, especially a higher gait speed, but also a higher hand grip strength and a faster chair stand test, were associated with independent ageing, while skeletal muscle index alone, and the composite sarcopenia phenotype measured with two different definitions, were not.

Association of Sarcopenia With Performance on Multiple Cognitive Domains: Results From the ELSA-Brasil Study

Background

Sarcopenia and cognitive impairment share pathophysiological paths and risk factors. Our aim was to investigate the association of sarcopenia and its defining components with cognitive performance in middle-aged and older adults.

Methods

This cross-sectional analysis included 5,038 participants from the ELSA-Brasil Study, aged ≥ 55 years. Muscle mass was evaluated by bioelectrical impedance analysis and muscle strength by handgrip strength. Sarcopenia was defined according to the Foundation for the National Institutes of Health. Cognition was evaluated using delayed word recall test, semantic verbal fluency test, and trail making test version B. Possible confounders included sociodemographic characteristics, lifestyle, and clinical comorbidities.

Results

The frequencies of sarcopenia, low muscle mass, and low muscle strength were 1.8%, 23.3%, and 4.4%, respectively. After adjustment for possible confounders, poorer performance on the verbal fluency test was associated with sarcopenia (β = −0.20, 95% confidence interval [CI] = −0.38; −0.01, p = .03) and low muscle mass (β = −0.08, 95% CI = −0.14; −0.01, p = .02). Low muscle strength was associated with poorer performance in the delayed word recall test (β = −0.14, 95% CI = −0.27; −0.02, p = .02), verbal fluency test (β = −0.14, 95% CI = −0.26; −0.02, p = .03), and trail making test (β = −0.15, 95% CI = −0.27; −0.03, p = .01).

Conclusions

Sarcopenia was associated with poorer performance on the verbal fluency test, and low muscle strength was associated with poorer performance in all cognitive tests in middle-aged and older adults.

Relationship between knee extension strength and gait styles in patients with dementia

This study aimed to investigate the relationship between knee extension strength and gait performance with walking aids and the threshold level of strength to predict gait performance with walking aids in patients with dementia using ordinal logistic modeling.This cross-sectional, observational correlation study was conducted in 56 hospital inpatients with dementia. Knee extensor strength was measured using a hand-held dynamometer. Gait performance was assessed by determining the walking aid that enables the subject to walk 10 m independently as well as without a walking aid.Ordinal logistic modeling showed that the strength of the knee extensor muscles was a significant gait predictor with walking aids (P = .028). Knee extension strength of 0.17, 0.43, and 0.57 N m/kg could reach 80% independence probability for gait with walker, with cane, and without walking aid, respectively.Knee extension strength was significantly related to gait performance with walking aid in people with dementia. Moreover, there are threshold levels of strength that could predict gait with particular walking aid in people with dementia. With regard to resistance training and prescription of walking aids, the probability of independence evaluated from ordinal logistic modeling contributes to efficient rehabilitation intervention.

Gait and dementia

Cognitive decline and neurodegenerative disease have been implicated in gait dysfunction via disturbance of top-down control mechanisms. Gait velocity decreases, variability increases, and ability to multitask while walking is impaired as cognition declines. Changes in gait can be used to predict incident mild cognitive impairment states as well as dementia. Slow gait velocity together with a cognitive complaint, the Motoric Cognitive Risk syndrome, can serve as a clinical biomarker for high risk of neurologic decline. While patients with Alzheimer's disease typically have quantitative gait impairment, those with other forms of dementia often manifest more overt, qualitative changes to walking. A variety of interventions may be useful to improve gait, including physical and cognitive rehabilitation, treatment of specific underlying causes of gait problems, and treatment of the dementia itself. Understanding the relationship between gait and dementia can elucidate pathology and improve patient care.

The impact of cognitive impairment on the physical ageing process

BACKGROUND

Physical decline and cognitive degeneration characterise the ageing process.

AIM

Physical parameters, performance and the functional indexes were studied in relation to age in healthy and cognitively impaired older persons to understand the interactions and changes during normal ageing, cognitive decline and progression to frailty.

METHODS

Cross-sectional analysis was performed on a data registry of an ambulatory Memory Diagnosis Centre. The quantitative gait characteristics at usual pace, body composition parameters, disability scales (activity of daily living and instrumental activity of daily living) and Rockwood frailty index were compared in cognitively healthy (CHI), mild cognitively impaired, mildly and moderately demented < 80-years old and > 80-years old adults.

RESULTS

Quality of gait deteriorated with age in CHI and cognitively impaired. Skeletal muscle mass index decreased when cognitive status worsened. Disability and frailty correlated with increasing cognitive impairment. Age, gender, cognitive impairment, body composition and Rockwood's Frailty scale had a combined forecasting effect, as well as the individual effect on the gait characteristics. Disability score, Frailty index, skeletal muscle mass and skeletal muscle mass index, gait speed, normalised mean step length and swing time variability in mildly demented < 80-years old adults mirrored the parameters in the CHI > 80-years old.

CONCLUSION

Quantitative gait characteristics, muscle mass and disabilities change along with cognitive impairment, frailty and age. A more rapid physical ageing process accompanies cognitive decline. Therefore, gait characteristics should be age-referenced and studies on gait in older persons should include muscle mass, frailty and cognitive parameters.

Physical fitness and dementia risk in the very old: a study of the Lothian Birth Cohort 1921

BACKGROUND

Previous studies have demonstrated that individual measures of fitness - such as reduced pulmonary function, slow walking speed and weak handgrip - are associated with an increased risk of dementia. Only a minority of participants included in these studies were aged over 80. The aim of this study was therefore to investigate the association between physical fitness and dementia in the oldest old.

METHODS

Subjects (n = 488) were enrolled in the Lothian Birth Cohort 1921 and aged 79 at baseline. Dementia cases arising after enrolment were determined using data from death certificates, electronic patient records and clinical reviews. Fitness measures included grip strength, forced expiratory volume in 1 s (FEV₁) and walking speed over 6 m, measured at 79 years. Dementia risk associated with each fitness variable was initially determined by logistic regression analysis, followed by Cox regression analysis, where death was considered as a competing risk. APOE ε4 status, age, sex, height, childhood IQ, smoking, history of cardiovascular or cerebrovascular disease, hypertension and diabetes were included as additional variables. Cumulative incidence graphs were calculated using Aalen-Johansen Estimator.

RESULTS

Although initial results indicated that greater FEV₁ was associated with an increased risk of dementia (OR (odds ratio per unit increase) 1.93, p = 0.03, n = 416), taking into account the competing risk of mortality, none of the fitness measures were found to be associated with dementia; FEV₁ (HR (hazard ratio per unit increase) 1.30, p = 0.37, n = 416), grip strength (HR 0.98, p = 0.35, n = 416), walking speed (HR 0.99, p = 0.90, n = 416). The presence of an APOE ɛ4 allele was however an important predictor for dementia (HR 2.85, p < 0.001, n = 416). Cumulative incidence graphs supported these findings, with an increased risk of dementia for APOE ɛ4 carriers compared with non-carriers. While increased FEV₁ was associated with reduced risk of death, there was no reduction in risk for dementia.

CONCLUSIONS

In contrast to previous studies, this study found that lower fitness beyond age 79 was not a risk factor for subsequent dementia. This finding is not explained by those with poorer physical fitness, who would have been more likely to develop dementia, having died before onset of dementia symptoms.

Sarcopenia and Muscle Functions at Various Stages of Alzheimer Disease

Although sarcopenia is closely linked to dementia, particularly Alzheimer disease (AD), there are few studies examining the prevalence and associated factors of sarcopenia in subjects with AD. This study aimed to investigate the prevalence of sarcopenia, factors associated with sarcopenia in elderly subjects with AD, and differences in muscle functions of the upper and lower extremities and gait speed at various stages of AD. We evaluated handgrip and knee extension strength, muscle mass, and gait speed in 285 elderly outpatients with probable AD (mean age 82. 0 ± 5.3 years), including early AD (n = 82), mild AD (n = 90), and moderate AD (n = 113), and 67 elderly outpatients with normal cognition (NC) (mean age 81.1 ± 4.7 years). Sarcopenia was defined according to the consensus of the Asian Working Group for Sarcopenia. The prevalence rate of sarcopenia was significantly higher in early AD, mild AD, and moderate AD than in NC (11% in NC, 36% in early AD, 45% in mild AD, and 60% in moderate AD of the female group, and 13% in NC, 41% in early AD, 47% in mild AD, and 47% in moderate AD of the male group). Age, body mass index, and Mini-mental state examination score were associated with sarcopenia in female or male AD groups. Decreased muscle strength without loss of muscle mass of the upper and lower extremities in the female AD group and those of the lower extremity in the AD male group were found in early and mild stages. Both muscle strength and mass decreased in the moderate AD. Low gait speed was also found in the early female and male AD which progressed with advancing dementia. Subjects with AD, even the early stages of AD, showed a high prevalence rate of sarcopenia. Higher age, lower BMI, and lower MMSE score were associated with sarcopenia in the female or male AD. There were differences in muscle functions and physical performance between the stages of the female and male AD.

Cognitive function and walking velocity in people with dementia; a comparison of backward and forward walking

How forward and backward walking, both central to everyday life, relate to cognition are relatively unexplored in people with dementia. This study aimed to investigate if forward and backward walking velocity respectively, associated with global cognition and executive function in people with dementia, and whether the association differed according to walking aid use or dementia type. Using a cross-sectional design, 161 participants (77% women), a mean Mini-Mental State Examination (MMSE) score of 15, and mean age of 85.5years and living in nursing homes were included. Self-paced forward walking (FW) and backward walking (BW) velocity over 2.4m was measured. Global cognitive outcome measurements included MMSE and Alzheimer Disease Assessment Scale - Cognitive subscale (ADAS-Cog). Executive function was measured using Verbal Fluency (VF). In comprehensively adjusted multivariate linear regression analyses, FW was independently associated with VF (p=0.001), but not MMSE (p=0.126) or ADAS-Cog (p=0.818). BW was independently associated with VF (p=0.043) and MMSE (p=0.022), but not ADAS-Cog (p=0.519). Interaction analyses showed that the association between BW velocity and executive function were stronger in participants who walked without a walking aid. No associations differed according to dementia type. In conclusion, executive function appears important to walking velocity, both forward and backward, in people with dementia with mild to moderately severe cognitive impairment. Global cognitive function was associated with backward walking only, perhaps due to it being more challenging. The association between BW velocity and executive function differed according to use of walking aids, which appeared to attenuate the association.

Gait Speed and Grip Strength Reflect Cognitive Impairment and Are Modestly Related to Incident Cognitive Decline in Memory Clinic Patients With Subjective Cognitive Decline and Mild Cognitive Impairment: Findings From the 4C Study

Background

Prospective studies in the general population show that slow gait speed is associated with cognitive decline and clinical progression to dementia. However, longitudinal studies in memory clinic populations are mostly lacking. We aimed to study the association between gait speed and grip strength and cognitive functioning at baseline and cognitive decline over time in memory clinic patients with subjective cognitive decline and mild cognitive impairment.

Methods

We included 309 patients (age 70 ± 9 years, 108 [35%] women, Mini-Mental State Examination 27 ± 3 points). Baseline gait speed was assessed over 15 feet, grip strength with a hydraulic hand dynamometer. Cognitive functioning was assessed annually with a comprehensive test battery during 3 years.

Results

Age- and gender-adjusted linear mixed models showed that slower gait speed was related to worse baseline attention, memory, information processing speed, and verbal fluency. Longitudinally, gait speed was related to decline in information processing speed and executive functioning. Weaker grip strength was related to worse baseline information processing speed and executive functioning but there were no longitudinal associations. Cox proportional hazards models revealed no significant associations with clinical progression.

Conclusions

Our findings suggest that markers of physical performance are related to current cognitive status and modestly related to cognitive decline but are seemingly not useful as an early marker of incident clinical progression.

Gait Speed and Decline in Gait Speed as Predictors of Incident Dementia

Background

Slow gait is common in dementia, but it remains unknown whether the slowing happens many years prior to dementia onset. We therefore examined the relationship between slow baseline gait speed (GS), change in GS, and the hazard of incident dementia in a community dwelling of elderly people.

Methods

A total of 3,663 participants dementia-free at baseline (mean age, 73.5 years) were followed up for 9 years from a prospective cohort (Three-City study, France) for incident dementia (all-cause, Alzheimer's disease, vascular dementia, and other causes). GS over 6 m was assessed 4 times over the follow-up using two photoelectric cells. We used a multistate model to estimate the hazard ratio (HR) of dementia for baseline GS and tested a washout period of 4 to 7 years. The role of GS change between 65 and 85 years was examined using linear mixed models and joint models for survival and longitudinal data.

Results

A total of 296 participants developed dementia during the follow-up. In age/sex-adjusted models, 1-SD (0.204 m/s) lower GS was associated with an increased hazard of dementia (HR = 1.59, 95% confidence interval [CI] = 1.39, 1.81, p < .001), with associations evident when gait assessments were taken from 4 years (HR = 1.46; CI = 1.26, 1.68) and 7 years (HR=1.30; CI = 1.00, 1.70) prior to dementia onset. Independently of baseline GS, those with a steeper decline had a higher hazard of dementia (HR per 1 SD [0.007 m/s/year] decrease = 3.39 [1.37-8.43], p = .009).

Conclusions

Gait is slower up to 7 years prior to clinical onset of dementia. Decline in GS is also more accelerated, suggesting strong links between cognitive and motor function in older adults.

Effects of Mobility and Cognition on Hospitalization and Inpatient Days in Women in Late Life

Background

This study examines effects of mobility and cognition on hospitalization and inpatient days among women late in life.

Methods

Prospective study of 663 women (mean age 87.7 years) participating in the Study of Osteoporotic Fractures Year 20 examination (2006-2008) linked with their inpatient claims data. At Year 20, mobility ascertained by Short Physical Performance Battery categorized as poor, intermediate, or good. Cognitive status adjudicated based on neuropsychological tests and classified as normal, mild cognitive impairment, or dementia. Hospitalizations (n = 182) during 12 months following Year 20.

Results

Reduced mobility and poorer cognition were each associated in a graded manner with higher inpatient health care utilization, even after accounting for each other and traditional prognostic indicators. For example, adjusted mean inpatient days per year were 0.94 (95% confidence interval [CI] 0.52-1.45) among women with good mobility increasing to 2.80 (95% CI 1.64-3.89) among women with poor mobility and 1.59 (95% CI 1.08-2.03) among women with normal cognition increasing to 2.53 (95% CI 1.55-3.40) among women with dementia. Women with poor mobility/dementia had a nearly sixfold increase in mean inpatient days per year (4.83, 95% CI 2.73-8.54) compared with women with good mobility/normal cognition (0.84, 95% CI 0.49-1.44).

Conclusions

Among women late in life, mobility limitations and cognitive deficits were each independent predictors of higher inpatient health care utilization even after considering each other and conventional predictors. Additive effects of reduced mobility and poorer cognition may be important to consider in medical decision making and health care policy planning for the growing population of adults aged ≥85 years.

What can gait tell us about dementia? Review of epidemiological and neuropsychological evidence

BACKGROUND

Cognitive impairment and gait disorders in people over the age of 65 represent major public health issues because of their high frequency, their link to poor outcomes and high costs. Research has demonstrated that these two geriatric syndromes are closely related.

METHODS AND RESULTS

We aim to review the evidence supporting the relationship between gait and cognitive impairment, particularly focusing on epidemiological and neuropsychological studies in patients with Mild cognitive impairment, Alzheimer's disease and Vascular dementia. The review demonstrates that gait and cognition are closely related, but our knowledge of their interrelationship is limited. Emerging evidence shows that gait analysis has the potential to contribute to diagnosis and prognosis of cognitive impairment.

CONCLUSIONS

An integrated approach for evaluating these major geriatric syndromes, based on their close relationship, will not only increase our understanding of cognitive-motor interactions, but most importantly may be used to aid early diagnosis, prognosis and the development of new interventions.

The developmental dynamics of gait maturation with a focus on spatiotemporal measures

Gait analysis is recognised as a powerful clinical tool for studying relationships between motor control and brain function. By drawing on the literature investigating gait in individuals with neurological disorders, this review provides insight into the neural processes that contribute to and regulate specific spatiotemporal sub-components of gait and how they may mature across early to late childhood. This review also discusses the roles of changing anthropomorphic characteristics, and maturing sensory and higher-order cognitive processes in differentiating the developmental trajectories of the sub-components of gait. Importantly, although studies have shown that cognitive-gait interference is larger in children compared to adults, the contributing neurocognitive mechanisms may vary across age groups who have different types of attentional or cognitive vulnerabilities. These findings have implications for current models of gait maturation by highlighting the need for a dynamic model that focuses on the integration of various factors that contribute to gait though experience and practice. This is essential to elucidating why gait and other motor deficits are often contiguous with cognitive neurodevelopmental disorders.

Risk Factors for Mild Cognitive Impairment, Dementia and Mortality: The Sydney Memory and Ageing Study

BACKGROUND

The nature and commonality of late-life risk factors for mild cognitive impairment (MCI), dementia, and mortality remain unclear. Our aim was to investigate potential risk factors, simultaneously in a single cohort including many individuals initially with normal cognition and followed for 6 years.

METHODS

We classified 873 community-dwelling individuals (70-90 years old and without dementia at baseline) from the Sydney Memory and Ageing Study as cognitively normal (CN), having MCI or dementia, or deceased 6 years after baseline. Associations with baseline demographic, lifestyle, health, and medical factors were investigated, including apolipoprotein (APOE) genotype, MCI at baseline, and reversion from MCI to CN within 2 years of baseline.

RESULTS

Eighty-three (9.5%) participants developed dementia and 114 (13%) died within 6 years; nearly 33% had MCI at baseline, of whom 28% reverted to CN within 2 years. A core set of baseline factors was associated with MCI and dementia at 6 years, including older age (per year: odds ratios and 95% confidence intervals = 1.08, 1.01-1.14 for MCI; 1.19, 1.09-1.31 for dementia), MCI at baseline (5.75, 3.49-9.49; 8.23, 3.93-17.22), poorer smelling ability (per extra test point: 0.89, 0.79-1.02; 0.80, 0.68-0.94), slower walking speed (per second: 1.12, 1.00-1.25; 1.21, 1.05-1.39), and being an APOE ε4 carrier (1.84, 1.07-3.14; 3.63, 1.68-7.82). All except APOE genotype were also associated with mortality (age: 1.11, 1.03-1.20; MCI: 3.87, 1.97-7.59; smelling ability: 0.83, 0.70-0.97; walking speed: 1.18, 1.03-1.34). Compared with stable CN participants, individuals reverting from MCI to CN after 2 years were at greater risk of future MCI (3.06, 1.63-5.72). Those who reverted exhibited some different associations between baseline risk factors and 6-year outcomes than individuals with stable MCI.

CONCLUSION

A core group of late-life risk factors indicative of physical and mental frailty are associated with each of dementia, MCI, and mortality after 6 years. Tests for slower walking speed and poorer smelling ability may help screen for cognitive decline. Individuals with normal cognition are at greater risk of future cognitive impairment if they have a history of MCI.

Comparison of motor performance of upper and lower extremities in dual-task tests in patients with mild Alzheimer's dementia

BACKGROUND

Alzheimer's dementia (AD) is a progressive disease that threatens the self-care and quality of life of elderly people. Early diagnosis and early treatment are crucial.

AIM

To examine the difference in executive function of patients with AD by analyzing their performance in gait analysis (Vicon MX system) and a trial making test (TMT) while counting forward or backward.

METHODS

Ten elderly persons who had been diagnosed by neurological specialists with mild AD were selected as study participants. Of these patients, 2 were men and 8 were women, and the average age was 74.0 ± 8.6 years. An additional group of 10 elderly persons without AD and matched according to age and sex constituted a control group.

RESULTS

The average Mini-Mental State Examination score was 17.7 ± 4.1, and the average clinical dementia rating scale score was 0.8 ± 0.3. We found that backward counting of 3 digits during gait performance in mild AD patients elicited substantial changes in velocity, cadence, coefficient of variation of the stride length, and stride time compared with those of the control group. Regarding upper extremity performance, all TMT tasks were highly sensitive in revealing differences in reaction time between the mild AD group and the control group.

DISCUSSION

Dual-task challenges for examining gait parameters and TMT performance can reveal obvious impairment of executive motor function in patients with very mild AD.

CONCLUSION

Dual-task motor tests of the upper extremities can be used as screening tools for detecting AD at an early stage.

Walking ability to predict future cognitive decline in old adults: A scoping review

Early identification of individuals at risk for cognitive decline may facilitate the selection of those who benefit most from interventions. Current models predicting cognitive decline include neuropsychological and/or biological markers. Additional markers based on walking ability might improve accuracy and specificity of these models because motor and cognitive functions share neuroanatomical structures and psychological processes. We reviewed the relationship between walking ability at one point of (mid) life and cognitive decline at follow-up. A systematic literature search identified 20 longitudinal studies. The average follow-up time was 4.5 years. Gait speed quantified walking ability in most studies (n=18). Additional gait measures (n=4) were step frequency, variability and step-length. Despite methodological weaknesses, results revealed that gait slowing (0.68-1.1 m/sec) preceded cognitive decline and the presence of dementia syndromes (maximal odds and hazard ratios of 10.4 and 11.1, respectively). The results indicate that measures of walking ability could serve as additional markers to predict cognitive decline. However, gait speed alone might lack specificity. We recommend gait analysis, including dynamic gait parameters, in clinical evaluations of patients with suspected cognitive decline. Future studies should focus on examining the specificity and accuracy of various gait characteristics to predict future cognitive decline.

Gait dyspraxia as a clinical marker of cognitive decline in Down syndrome: A review of theory and proposed mechanisms

Down syndrome (DS) is the most common genetic cause of intellectual disability in children. With aging, DS is associated with an increased risk for Alzheimer's disease (AD). The development of AD neuropathology in individuals with DS can result in further disturbances in cognition and behavior and may significantly exacerbate caregiver burden. Early detection may allow for appropriate preparation by caregivers. Recent literature suggests that declines in gait may serve as an early marker of AD-related cognitive disorders; however, this relationship has not been examined in individuals with DS. The theory regarding gait dyspraxia and cognitive decline in the general population is reviewed, and potential applications to the population with individuals with DS are highlighted. Challenges and benefits in the line of inquiry are discussed. In particular, it appears that gait declines in aging individuals with DS may be associated with known declines in frontoparietal gray matter, development of AD-related pathology, and white matter losses in tracts critical to motor control. These changes are also potentially related to the cognitive and functional changes often observed during the same chronological period as gait declines in adults with DS. Gait declines may be an early marker of cognitive change, related to the development of underlying AD-related pathology, in individuals with DS. Future investigations in this area may provide insight into the clinical changes associated with development of AD pathology in both the population with DS and the general population, enhancing efforts for optimal patient and caregiver support and propelling investigations regarding safety/quality of life interventions and disease-modifying interventions.

RISK FACTORS FOR SLOW GAIT SPEED: A NESTED CASE-CONTROL SECONDARY ANALYSIS OF THE MEXICAN HEALTH AND AGING STUDY

BACKGROUND

Physical performance tests play a major role in the geriatric assessment. In particular, gait speed has shown to be useful for predicting adverse outcomes. However, risk factors for slow gait speed (slowness) are not clearly described.

OBJECTIVES

To determine risk factors associated with slowness in Mexican older adults.

DESIGN

A two-step process was adopted for exploring the antecedent risk factors of slow gait speed. First, the cut-off values for gait speed were determined in a representative sample of Mexican older adults. Then, antecedent risk factors of slow gait speed (defined using the identified cut-points) were explored in a nested, cohort case-control study.

SETTING PARTICIPANTS

One representative sample of a cross-sectional survey for the first step and the Mexican Health and Aging Study (a cohort characterized by a 10-year follow-up).

MEASUREMENTS

A 4-meter usual gait speed test was conducted. Lowest gender and height-stratified groups were considered as defining slow gait speed. Sociodemographic characteristics, comorbidities, psychological and health-care related variables were explored to find those associated with the subsequent development of slow gait speed. Unadjusted and adjusted logistic regression models were performed.

RESULTS

In the final model, age, diabetes, hypertension, and history of fractures were associated with the development of slow gait speed.

CONCLUSIONS

Early identification of subjects at risk of developing slow gait speed may halt the path to disability due to the robust association of this physical performance test with functional decline.

Poor Gait Performance and Prediction of Dementia: Results From a Meta-Analysis

BACKGROUND

Poor gait performance predicts risk of developing dementia. No structured critical evaluation has been conducted to study this association yet. The aim of this meta-analysis was to systematically examine the association of poor gait performance with incidence of dementia.

METHODS

An English and French Medline search was conducted in June 2015, with no limit of date, using the medical subject headings terms "Gait" OR "Gait Disorders, Neurologic" OR "Gait Apraxia" OR "Gait Ataxia" AND "Dementia" OR "Frontotemporal Dementia" OR "Dementia, Multi-Infarct" OR "Dementia, Vascular" OR "Alzheimer Disease" OR "Lewy Body Disease" OR "Frontotemporal Dementia With Motor Neuron Disease" (Supplementary Concept). Poor gait performance was defined by standardized tests of walking, and dementia was diagnosed according to international consensus criteria. Four etiologies of dementia were identified: any dementia, Alzheimer disease (AD), vascular dementia (VaD), and non-AD (ie, pooling VaD, mixed dementias, and other dementias). Fixed effects meta-analyses were performed on the estimates in order to generate summary values.

RESULTS

Of the 796 identified abstracts, 12 (1.5%) were included in this systematic review and meta-analysis. Poor gait performance predicted dementia [pooled hazard ratio (HR) combined with relative risk and odds ratio = 1.53 with P < .001 for any dementia, pooled HR = 1.79 with P < .001 for VaD, HR = 1.89 with P value < .001 for non-AD]. Findings were weaker for predicting AD (HR = 1.03 with P value = .004).

CONCLUSIONS

This meta-analysis provides evidence that poor gait performance predicts dementia. This association depends on the type of dementia; poor gait performance is a stronger predictor of non-AD dementias than AD.

Body Composition and Anti-Neoplastic Treatment in Adult and Older Subjects - A Systematic Review

BACKGROUND

The estimation of the risk of poor tolerance and overdose of antineoplastic agents protocols represents a major challenge in oncology, particularly in older patients. We hypothesize that age-related modifications of body composition (i.e. increased fat mass and decreased lean mass) may significantly affect tolerance to chemotherapy.

METHOD

We conducted a systematic review for the last 25 years (between 1990 and 2015), using US National library of Medicine Medline electronic bibliographic database and Embase database of cohorts or clinical trials exploring (i) the interactions of body composition (assessed by Dual X-ray Absorptiometry, Bioelectrical Impedance Analyses, or Computerized Tomography) with pharmacokinetics parameters, (ii) the tolerance to chemotherapy, and (iii) the consequences of chemotherapies or targeted therapies on body composition.

RESULTS

Our search identified 1504 articles. After a selection (using pre-established criteria) on titles and abstract, 24 original articles were selected with 3 domains of interest: impact of body composition on pharmacokinetics (7 articles), relationship between body composition and chemotoxicity (14 articles), and effect of anti-cancer chemotherapy on body composition (11 articles). The selected studies suggested that pharmacokinetic was influenced by lean mass, that lower lean mass could be correlated with toxicity, and that sarcopenic patients experienced more toxicities that non-sarcopenic patients. Regarding fat mass, results were less conclusive. No studies specifically explored the topic of body composition in older cancer patients.

CONCLUSIONS

Plausible pathophysiological pathways linking body composition, toxicity, and pharmacokinetics are sustained by the actual review. However, despite the growing number of older cancer patients, our review highlighted the lack of specific studies in the field of anti-neoplastic agents toxicity regarding body composition conducted in elderly.