Executive function, memory, and gait speed decline in well-functioning older adults

Medial Temporal Lobe Atrophy in Older Adults With Subjective Cognitive Impairments Affects Gait Parameters in the Spatial Navigation Task

Both navigation abilities and gait can be affected by the atrophy in the medial temporal cortex. This study aimed to determine whether navigation abilities could differentiate seniors with and without medial temporal lobe atrophy who complained about their cognitive status. The participants, classified to either the medial temporal atrophy group (n = 23) or the control group (n = 22) underwent neuropsychological assessment and performed a spatial navigation task while their gait parameters were recorded. The study showed no significant differences between the two groups in memory, fluency, and semantic knowledge or typical measures of navigating abilities. However, gait parameters, particularly the propulsion index during certain phases of the navigation task, distinguished between seniors with and without medial temporal lobe lesions. These findings suggest that the gait parameters in the navigation task may be a valuable tool for identifying seniors with cognitive complaints and subtle medial temporal atrophy.

Temporal Patterns of Change in Physical and Cognitive Performance

BACKGROUND

This study examined the relation between declines in physical and cognitive performance in older people.

METHODS

A population-based cohort of 7 483 adults (average age 72 years) were interviewed. Physical performance was assessed with 3 standardized tests and a combination of 4 cognitive tests was used to assess cognitive function. Rate of change in physical and cognitive performance was determined for each interval between interviews. In mixed effects linear regression models adjusted for age, sex, race, and study time, and change in each factor was used to predict change in the other factor. We examined time associations by using changes in the predictor measured at 1, 2, or 3 intervals before the outcome change.

RESULTS

Decline in cognitive function was most strongly predicted by physical decline in the same 3-year interval. The decline in cognitive function was weaker in the 1-time interval after the decline in physical function and was not significant in later intervals. When a decline in cognitive function was used to predict a decline in physical function, the results were similar. The strongest association occurred in the same time interval so that declines in cognitive and physical performance tend to occur together.

CONCLUSIONS

Decline in cognition and physical function seem to occur together in a short timeframe. It is important to investigate the reasons for these changes that are short-term to guide the development of interventions.

[Interpretation of a concept for functional movement disorders from the perspective of older patients]

A recently published concept considers a significant proportion of the occurrence and persistence of functional movement disorders (FMD) to be explained by increased/incorrect weighting of the expected movement (feedforward signal) in the presence of decreased/altered actual feedback of the movement. In the context of aging and age-associated diseases, there is an increased likelihood that these prerequisites will occur, also in combination. For example, the feedforward signal can be enhanced by accumulation of a wealth of experience but can for example become prone to error due to changes in attention and (fear of) falling. Conversely, the actual feedback is subject to age-related changes, such as reduction of sensory functions. This could explain why FMDs also occur in old age and offer treatment approaches for this so far poorly studied disorder. It follows that a specific focus on (the correction of) feedforward signals and strengthening as well as training of the actual feedback are potentially promising therapeutic approaches for older people with FMD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Health, Aging, and Body Composition (Health ABC) Study-Ground-Breaking Science for 25 Years and Counting

BACKGROUND

The Health, Aging, and Body Composition Study is a longitudinal cohort study that started just over 25 years ago. This ground-breaking study tested specific hypotheses about the importance of weight, body composition, and weight-related health conditions for incident functional limitation in older adults.

METHODS

Narrative review with analysis of ancillary studies, career awards, publications, and citations.

RESULTS

Key findings of the study demonstrated the importance of body composition as a whole, both fat and lean mass, in the disablement pathway. The quality of the muscle in terms of its strength and its composition was found to be a critical feature in defining sarcopenia. Dietary patterns and especially protein intake, social factors, and cognition were found to be critical elements for functional limitation and disability. The study is highly cited and its assessments have been widely adopted in both observational studies and clinical trials. Its impact continues as a platform for collaboration and career development.

CONCLUSIONS

The Health ABC provides a knowledge base for the prevention of disability and promotion of mobility in older adults.

Relationship between Mild Cognitive Impairment, Pre-Frailty, Physical and Psychological Functioning, and Functional Capacity among Community-Dwelling Older Adults

Mild cognitive impairment (MCI) is associated with a high risk of dementia. Reportedly, 54.6% of older adults with MCI fall into the pre-frailty category. However, it is unclear what differences exist in older adults with regard to their physical, psychological, and functional capacities, which depend on MCI, pre-frailty, or a combination of the two. This study aimed to examine the differences between the association between physical function, psychological function, and functional capacity by examining a combination of MCI and pre-frailty among community-dwelling older Japanese individuals. The participants in the analysis were 236 older people living in the community. They were classified into four groups, as follows: normal, MCI only, pre-frailty only, and pre-frailty/MCI; furthermore, their physical, psychological, and functional capacities were compared. In addition, a multinomial logistic regression analysis was performed using MCI and pre-frailty as dependent variables. No associated factors were identified for MCI only, and a depressive mood was only associated with pre-frailty. When pre-frailty and MCI were combined, knee extension muscle strength, fastest gait speed, the s30 s chair stand test, depressed moods, and the instrumental activities of daily living (IADL) were correlated. Our results suggest that when MCI and pre-frailty are combined, declines in both physical and psychological functions and IADL are likely to occur.

Age-varying association between depression symptoms and executive function among older adults: Moderation by physical activity

OBJECTIVES

This study assessed trends in depression symptoms, executive function, and their association across age among older adults. Subgroup comparisons were made between older adults meeting and not meeting physical activity guidelines on variables and associations of interest.

METHODS

Participants (n = 2473) were older adults ages 60 to 79 from the 2011-2014 National Health and Nutrition Examination Survey. Depression symptoms, executive function, and physical activity were assessed, and weighted time-varying effect modeling was used for analyses.

RESULTS

Depression symptoms were most severe at age 62 followed by a modest decline before a second peak around age 67. Executive function was highest at age 60 and declined steadily through age 77. Depression symptoms and executive function were negatively associated, but the strength and significance of this association varied with age. Older adults meeting physical activity guidelines had increased executive function and less severe depression symptoms, and meeting physical activity guidelines buffered the association between depression symptoms and executive function at key ages during older adulthood.

CONCLUSIONS

Differences by age should be considered when designing and implementing health programs and treatments focusing on mental health and cognition in older adulthood. Encouraging moderate-intensity physical activity may help protect older adults from depression-related cognitive decline.

Relationship of Neural Correlates of Gait Characteristics and Cognitive Dysfunction in Patients with Mild Cognitive Impairment

Background: Some patients with mild cognitive impairment (MCI) experience gait disturbances. However, there are few reports on the relationship between gait disturbance and cognitive function in patients with MCI. Therefore, we investigated the neural correlates of gait characteristics related to cognitive dysfunction. Methods: Eighty patients diagnosed with MCI from three dementia centers in Gangwon-do, Korea, were recruited for this study. We defined MCI as a Clinical Dementia Rating global score of 0.5 or higher, with a memory domain score of 0.5 or greater. The patients were classified as having either higher or lower MMSE and the groups were based on their Mini Mental Status Examination z-scores. Multiple logistic regression analysis was performed to examine the association between the gait characteristics and cognitive impairment. Analyses included variables such as age, sex, years of education, number of comorbidities, body mass index, and height. Results: Gait velocity, step count, step length, heel-to-heel base support, swing and stance phase duration, and support time were associated with cognitive function. A decrease in gray matter volume in the right pericalcarine area was associated with gait characteristics related to cognitive dysfunction. An increase in the curvature of gray matter in the right entorhinal, right lateral orbitofrontal, right cuneus, and right and left pars opercularis areas was also associated with gait characteristics related to cognitive dysfunction. Conclusion: Since gait impairment is an important factor in determining activities of daily living in patients with mild cognitive impairment, the evaluation of gait and cognitive functions in patients with mild cognitive impairment is important.

Winning the race with aging: age-related changes in gait speed and its association with cognitive performance in dogs

Introduction

In humans, gait speed is a crucial component in geriatric evaluation since decreasing speed can be a harbinger of cognitive decline and dementia. Aging companion dogs can suffer from age-related mobility impairment, cognitive decline and dementia known as canine cognitive dysfunction syndrome. We hypothesized that there would be an association between gait speed and cognition in aging dogs.

Methods

We measured gait speed on and off leash in 46 adult and 49 senior dogs. Cognitive performance in senior dogs was assessed by means of the Canine Dementia Scale and a battery of cognitive tests.

Results

We demonstrated that dogs' food-motivated gait speed off leash is correlated with fractional lifespan and cognitive performance in dogs, particularly in the domains of attention and working memory.

Discussion

Food-motivated gait speed off leash represents a relatively easy variable to measure in clinical settings. Moreover, it proves to be a more effective indicator of age-related deterioration and cognitive decline than gait speed on leash.

The Effects of 12-Week Dual-Task Physical-Cognitive Training on Gait, Balance, Lower Extremity Muscle Strength, and Cognition in Older Adult Women: A Randomized Study

This study aims to investigate the effects of dual-task physical-cognitive the training on body balance (BB), gait performance (GP), lower limb muscle strength (LEMS), and cognitive performance (CP) in a group of cognitively normal older adult women (n = 44; 66.20 ± 4.05 years). Of these, 22 were randomly allocated to the dual-task training (DT) group, and 22 participated in the control group (CG). Assessments were performed at baseline, after 12 weeks of intervention, and at the end of 12 weeks of follow-up, using the following instruments: Timed Up & Go (TUG), Timed Up & Go manual (TUGm), Timed Up & Go cognitive (TUGc), Balance Test (TEC), sit-to-stand test (STS), and verbal fluency test (VF). After 12 weeks of DT training, participants showed a significant time × group interaction in all motor assessments (BB, GP, LEMS), as well as in three cognitive tests (VF-grouping, VF-exchange, VF-total). No time-group interaction effect was indicated for the VF-category test. At all evaluation times, CG members maintained constant physical and cognitive performance. We conclude that 12 weeks of physical-cognitive DT training was effective in promoting BB, GP, and LEMS, as well as CP in cognitively normal older adult women, with lasting effects up to 12 weeks after the intervention.

Sarcopenia and Cognitive Decline in Older Adults: Targeting the Muscle-Brain Axis

Declines in physical performance and cognition are commonly observed in older adults. The geroscience paradigm posits that a set of processes and pathways shared among age-associated conditions may also serve as a molecular explanation for the complex pathophysiology of physical frailty, sarcopenia, and cognitive decline. Mitochondrial dysfunction, inflammation, metabolic alterations, declines in cellular stemness, and altered intracellular signaling have been observed in muscle aging. Neurological factors have also been included among the determinants of sarcopenia. Neuromuscular junctions (NMJs) are synapses bridging nervous and skeletal muscle systems with a relevant role in age-related musculoskeletal derangement. Patterns of circulating metabolic and neurotrophic factors have been associated with physical frailty and sarcopenia. These factors are mostly related to disarrangements in protein-to-energy conversion as well as reduced calorie and protein intake to sustain muscle mass. A link between sarcopenia and cognitive decline in older adults has also been described with a possible role for muscle-derived mediators (i.e., myokines) in mediating muscle-brain crosstalk. Herein, we discuss the main molecular mechanisms and factors involved in the muscle-brain axis and their possible implication in cognitive decline in older adults. An overview of current behavioral strategies that allegedly act on the muscle-brain axis is also provided.

Uneven terrain versus dual-task walking: differential challenges imposed on walking behavior in older adults are predicted by cognitive and sensorimotor function

Aging is associated with declines in walking function. To understand these mobility declines, many studies have obtained measurements while participants walk on flat surfaces in laboratory settings during concurrent cognitive task performance (dual-tasking). This may not adequately capture the real-world challenges of walking at home and around the community. Here, we hypothesized that uneven terrains in the walking path impose differential changes to walking speed compared to dual-task walking. We also hypothesized that changes in walking speed resulting from uneven terrains will be better predicted by sensorimotor function than cognitive function. Sixty-three community-dwelling older adults (65-93 yrs old) performed overground walking under varying walking conditions. Older adults were classified into two mobility function groups based on scores of the Short Physical Performance Battery. They performed uneven terrain walking across four surface conditions (Flat, Low, Medium, and High unevenness) and performed single and verbal dual-task walking on flat ground. Participants also underwent a battery of cognitive (cognitive flexibility, working memory, inhibition) and sensorimotor testing (grip strength, 2-pt discrimination, pressure pain threshold). Our results showed that walking speed decreased during both dual-task walking and across uneven terrain walking conditions compared to walking on flat terrain. Participants with lower mobility function had even greater decreases in uneven terrain walking speeds. The change in uneven terrain speed was associated with attention and inhibitory function. Changes in both dual-task and uneven terrain walking speeds were associated with 2-point tactile discrimination. This study further documents associations between mobility, executive functions, and somatosensation, highlights the differential costs to walking imposed by uneven terrains, and identifies that older adults with lower mobility function are more likely to experience these changes to walking function.

Longitudinal Changes in Dual Decline in Memory and Gait Speed Association with Instrumental Activities of Daily Living: Findings from the National Social Life, Health, and Aging Project

Objective: We investigated the association between dual decline (DD) (loss of memory and gait speed) and the instrumental activities of daily living (IADL) degeneration in older adults. Methods: Data were drawn from the National Social Life, Health, and Aging Project (NSHAP) reflecting changes over 5 years. This study used the NSHAP data set wave 2 (2010-2011, N = 3196) and wave 3 (2015-2016, N = 4377). Results: Data from 1640 participants were retrieved. There were 601 people with DD and 1039 people without-DD. The DD group had a 28.4% (95% CI = 1.013-1.626) greater risk of degrading in IADL than the without-DD group (odds ratio = 1.284, p < .05). Conclusion: Current research can be used when establishing intervention programs or policies that can prevent IADL degradation through simple memory training and walking activities for older adults living in the community.

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

Background

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

Methods

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

Results

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

Conclusion

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

Machine Learning and Eye Movements Give Insights into Neurodegenerative Disease Mechanisms

Humans are a vision-dominated species; what we perceive depends on where we look. Therefore, eye movements (EMs) are essential to our interactions with the environment, and experimental findings show EMs are affected in neurodegenerative disorders (ND). This could be a reason for some cognitive and movement disorders in ND. Therefore, we aim to establish whether changes in EM-evoked responses can tell us about the progression of ND, such as Alzheimer's (AD) and Parkinson's diseases (PD), in different stages. In the present review, we have analyzed the results of psychological, neurological, and EM (saccades, antisaccades, pursuit) tests to predict disease progression with machine learning (ML) methods. Thanks to ML algorithms, from the high-dimensional parameter space, we were able to find significant EM changes related to ND symptoms that gave us insights into ND mechanisms. The predictive algorithms described use various approaches, including granular computing, Naive Bayes, Decision Trees/Tables, logistic regression, C-/Linear SVC, KNC, and Random Forest. We demonstrated that EM is a robust biomarker for assessing symptom progression in PD and AD. There are navigation problems in 3D space in both diseases. Consequently, we investigated EM experiments in the virtual space and how they may help find neurodegeneration-related brain changes, e.g., related to place or/and orientation problems. In conclusion, EM parameters with clinical symptoms are powerful precision instruments that, in addition to their potential for predictions of ND progression with the help of ML, could be used to indicate the different preclinical stages of both diseases.

N-acetyl-aspartate and Myo-inositol as Markers of White Matter Microstructural Organization in Mild Cognitive Impairment: Evidence from a DTI-(1)H-MRS Pilot Study

We implemented a multimodal approach to examine associations between structural and neurochemical changes that could signify neurodegenerative processes related to mild cognitive impairment (MCI). Fifty-nine older adults (60-85 years; 22 MCI) underwent whole-brain structural 3T MRI (T1W, T2W, DTI) and proton magnetic resonance spectroscopy (¹H-MRS). The regions of interest (ROIs) for ¹H-MRS measurements were the dorsal posterior cingulate cortex, left hippocampal cortex, left medial temporal cortex, left primary sensorimotor cortex, and right dorsolateral prefrontal cortex. The findings revealed that subjects in the MCI group showed moderate to strong positive associations between the total N-acetylaspartate to total creatine and the total N-acetylaspartate to myo-inositol ratios in the hippocampus and dorsal posterior cingulate cortex and fractional anisotropy (FA) of WM tracts crossing these regions-specifically, the left temporal tapetum, right corona radiata, and right posterior cingulate gyri. In addition, negative associations between the myo-inositol to total creatine ratio and FA of the left temporal tapetum and right posterior cingulate gyri were observed. These observations suggest that the biochemical integrity of the hippocampus and cingulate cortex is associated with a microstructural organization of ipsilateral WM tracts originating in the hippocampus. Specifically, elevated myo-inositol might be an underlying mechanism for decreased connectivity between the hippocampus and the prefrontal/cingulate cortex in MCI.

Examining the intersection of cognitive and physical function measures: Results from the brain networks and mobility (B-NET) study

Background and objectives

Although evidence exists that measures of mobility and cognition are correlated, it is not known to what extent they overlap, especially across various domains. This study aimed to investigate the intersection of 18 different objective cognitive and physical function measures from a sample of unimpaired adults aged 70 years and older.

Research design and methods

Canonical correlation analysis was utilized to explore the joint cross-sectional relationship between 13 cognitive and 6 physical function measures in the baseline visit of the Brain Networks and Mobility Function (B-NET) Study (n = 192).

Results

Mean age of participants was 76.4 years. Two synthetic functions were identified. Function 1 explained 26.3% of the shared variability between the cognition and physical function variables, whereas Function 2 explained 19.5%. Function 1 termed "cognitive and physical speed" related the expanded Short Physical Performance Battery (eSPPB), 400-m walk speed, and Dual Task gait speed measures of physical function to semantic fluency animals scores, Digit Symbol Coding (DSC), and Trail Making Test B. Function 2 termed "complex motor tasks and cognitive tasks" related the Force Plate Postural Sway Foam Task and Dual Task to the following cognitive variables: MoCA Adjusted Score, Verbal Fluency L words, Craft story immediate and delayed recall, and Trail Making Test B.

Discussion and implications

We identified groups of cognitive and physical functional abilities that were linked in cross-sectional analyses, which may suggest shared underlying neural network pathway(s) related to speed (Function 1) or complexity (Function 2).

Translational significance

Whether such neural processes decline before measurable functional losses or may be important targets for future interventions that aim to prevent disability also remains to be determined.

Sarcopenia is associated with mild-to-moderate chronic kidney disease in Chinese community-dwelling older men but not in women

OBJECTIVE

To determine whether a relationship exists between sarcopenia, including its individual components (muscle mass, muscle strength and gait speed), and mild-to-moderate chronic kidney disease (CKD) in Chinese older adults.

METHODS

This cross-sectional study comprised participants aged ≥60 years from Tianjin and Shanghai, China, who joined a national free physical examination program between 2014 and 2019, and consented to study inclusion. Sarcopenia was defined according to the Asian Working Group for Sarcopenia (2019 version). Mild-to-moderate CKD was defined as estimated glomerular filtration rate (eGFR) between 45 ml/min/1.73 m² and 60 ml/min/1.73 m².

RESULTS

A total of 1627 participants were included (mean age, 69.32 ± 6.17 years; 43.8% male). Sarcopenia was significantly associated with mild-to-moderate CKD in men but not women. Among three physical performance components, slow gait speed (odds ratio 1.89, 95% confidence interval 1.38, 2.58) was associated with mild-to-moderate CKD in both men and women after adjusting for all other variables.

CONCLUSIONS

Sarcopenia was closely associated with mild-to-moderate CKD in older men, and slow gait speed was related to mild-to-moderate CKD in men and women. These findings may help guide better diagnosis and management of CKD in the context of slow gait speed, and facilitate earlier CKD detection and appropriate intervention in older adults.

Dyadic Links Between Health Changes and Well-Being: The Role of Non-Spousal Confidants

Although the marital relationship is often the primary source of emotional support in adulthood, sole reliance on the spouse to discuss health-related issues may be harmful to the well-being of both partners. The first aim of this study was to examine whether declines in health during later life would be associated with poorer psychological well-being in self and partner. We further investigated whether declining health would have a stronger impact on own and partner psychological well-being in the absence of non-spousal health confidants. Longitudinal actor-partner interdependence models (APIMs) were used to test both hypotheses with dyadic data from Wave 2 (2010-2011) and Wave 3 (2015-2016) of the National Social Life, Health, and Aging Project (NSHAP). Contrary to prediction, increased anxiety following spousal declines in gait speed and cognitive function occurred for those whose spouse did (rather than did not) have additional health confidants. A much fuller understanding is needed in regard to whether close relationships provide resources or present unwanted complications to dyadic coping, and the processes by which effects occur.

Undiagnosed Dementia Is Associated with Poor Physical Function in Older Adults

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Role of Cognitive Performance and Physical Functions in the Association between Age and Gait Speed: A Mediation Study

Simple Summary

Age and mobility are interrelated. In this context, cognitive performance (CP) and physical functions (PF) play a mediating role. However, these concepts are multifaceted, and their interrelationships need further investigations. Thus, our study aims (1) to investigate the association between CP and PF with GS and (2) to examine whether CP and PF mediate the association between age and GS in a large sample of older Brazilian adults. The findings show that low levels of CP and PF were associated with a greater chance of the older individual presenting a slow GS. Moreover, the mediation model indicated that CP and PF mediated, by approximately 12% and 98%, respectively, the association between age and GS.

Abstract

Introduction: With vulnerable aging, gait speed (GS) undergoes progressive changes, becoming slower. In this process, cognitive performance (CP) and physical function (PF) both play an important role. This study aims (1) to investigate the association between CP and PF with GS and (2) to examine whether CP and PF mediate the association between age and GS in a large sample of Brazilian older adults. Methods: A cross-sectional study analyzed 697 individuals (mean age 70.35 ± 6.86 years) from the state of Amazonas. The CP was evaluated by the COGTEL test battery, PF by the Senior Fitness Test battery, and GS with the 50-foot Walk Test. Results: Older adults with a lower CP and PF had a 70% and 86% chance of slow GS, respectively. When CP and PF were placed simultaneously as mediators, the direct effect estimated by the model revealed a non-significant relationship between age and GS. Specifically, CP and PF mediated the association between age and GS, at approximately 12% and 98%, respectively. Conclusions: CP and PF show the potential to estimate GS performance among older adults. Moreover, CP and PF indicated a negative and direct association between age and slow GS, especially PF.

Cognitive, psychological and social factors associated with older adults' mobility: a scoping review of self-report and performance-based measures

Although many factors have been associated with mobility among older adults, there is paucity of research that explores the complexity of factors that influence mobility. This review aims to synthesise the available evidence for factors comprising the cognitive, psychological, and social mobility determinants and their associations with mobility self-reported and performance-based outcomes in older adults (60 years). We followed Arksey and O'Malley's five stages of a scoping review and searched PubMed, EMBASE, PsychINFO, Web of Science, AgeLine, Allied and Complementary Medicine Database, Cumulative Index to Nursing and Allied Health Literature and Sociological Abstract databases. Reviewers in pairs independently conducted title, abstract, full-text screening and data extraction. We reported associations by analyses rather than articles because articles reported multiple associations for factors and several mobility outcomes. Associations were categorised as significantly positive, negative, or not significant. We included 183 peer-reviewed articles published in 27 countries, most of which were cross-sectional studies and conducted among community-dwelling older adults. The 183 articles reported 630 analyses, of which 381 (60.5%) were significantly associated with mobility outcomes in the expected direction. For example, older adults with higher cognitive functioning such as better executive functioning had better mobility outcomes (e.g., faster gait speed), and those with poor psychological outcomes, such as depressive symptoms, or social outcomes such as reduced social network, had poorer mobility outcomes (e.g., slower gait speed) compared to their counterparts. Studies exploring the association between cognitive factors, personality (a psychological factor) and self-reported mobility outcomes (e.g., walking for transportation or driving), and social factors and performance-based mobility outcomes in older adults are limited. Understanding the additive relationships between cognitive, psychological, and social factors highlights the complexity of older adults' mobility across different forms of mobility, including independence, use of assistive devices, transportation, and driving.

Gait Speed as a Biomarker of Cognitive Vulnerability: A Population-Based Study with Cognitively Normal Older Adults

We aimed to examine associations between cognitive vulnerability and gait speed (GS) in a large older sample. A cross-sectional study analyzed data from the “Health, Lifestyle and Fitness in Adults and Seniors in Amazonas” (SEVAAI) project. In total, 697 participants were included (mean age 70.35 ± 6.86 years). Usual and fast GS were evaluated, and cognitive performance was examined by the COGTEL test battery. There was a positive and large correlation between cognition (COGTEL score) and usual GS (r = 0.510; p < 0.001) and fast GS (r = 0.503; p < 0.001). The usual GS, as a continuous variable, indicated a chance of improved cognitive performance by up to 55%, and fast GS by up to 82%. After controlling for potential confounders (i.e., sex, age, MMSE and years of education), usual and fast GS indicated a chance of improving cognition, respectively, in 57% and 85%. Analysis of GS in quartiles (Q) showed high and significant associations between usual and fast GS and cognitive vulnerability. GS classified as Q1 (slower), Q2 and Q3 represented a greater chance of presenting cognitive deficits, respectively, than in participants with both GS classified as Q4 (highest). Cognitive vulnerability was associated with low GS. Usual and fast GS can be used as complementary measures for the evaluation of cognitively normal Brazilian older adults.

Relative Trajectories of Gait and Cognitive Decline in Aging

BACKGROUND

Gait and cognition decline with advancing age, and presage the onset of dementia. Yet, the relative trajectories of gait and cognitive decline in aging are poorly understood-particularly among those with the motoric cognitive risk (MCR) syndrome. This study compared changes in simple and complex gait performance and cognition, as a function of age and MCR.

METHODS

We examined gait and cognitive functions of 1 095 LonGenity study participants (mean age = 75.4 ± 6.7 years) with up to 12 years of annual follow-up. Participants were of Ashkenazi Jewish descent, free of dementia, ambulatory, and had a 12.2% MCR prevalence at baseline. Gait speed was measured at usual pace walking (single-task walking, STW-speed) and walking while talking (WWT-speed). Eleven neuropsychological test scores were examined separately, and as a global cognition composite. Linear mixed-effects models adjusted for baseline sex, education, parental longevity, cognitive impairment, and global health were used to estimate changes in gait and cognition, as a function of age and MCR.

RESULTS

STW-speed, WWT-speed, and cognitive tests performance declined in a nonlinear (accelerating) fashion with age. STW-speed declined faster than WWT-speed and cognitive test scores. People with MCR showed faster rates of decline on figure copy and phonemic fluency.

CONCLUSIONS

Gait declines at a faster rate than cognition in aging. People with MCR are susceptible to faster decline in visuospatial, executive, and language functions. This study adds important knowledge of trajectories of gait and cognitive decline in aging, and identifies MCR as a risk factor for accelerated cognitive decline.

Gradient and Acceleration of Decline in Physical and Cognitive Functions in Older Adults: A Disparity Analysis

BACKGROUND

Substantive previous work has shown that both gait speed and global cognition decline as people age. Rates of their decline, as opposed to cross-sectional measurements, could be more informative of future functional status and other clinical outcomes because they more accurately represent deteriorating systems. Additionally, understanding the sex and racial disparity in the speed of deterioration, if any, is also important as ethnic minorities are at an increased risk of mobility disability and dementia.

METHOD

Data from 2 large longitudinal intervention studies were integrated. Rates of decline were derived from individual-level measures of gait speed of 400-m walk and scores on the Modified Mini Mental State Examination (3MSE). We also assessed age-associated declines and accelerations in changes across the ages represented in the studies (age range 53-90).

RESULTS

The mean rate of decline in 400-m gait speed across individuals was 0.03 m/s per year, and multivariable analysis showed a significant acceleration in decline of -0.0013 m/s/y2 (p < .001). Both race and sex moderated the rate of decline. For global cognition, the mean rate of decline was 0.05 of a point per year on the 3MSE scale, and acceleration in the rate of decline was significant (-0.017 point/y2, p < .001), but neither sex nor race moderated the decline.

CONCLUSION

Rate of decline in physical but not cognitive function appears moderated by sex and race. This finding, as well as rates and accelerations of decline estimated herein, could inform future intervention studies.

CLINICAL TRIALS REGISTRATION NUMBER

NCT00017953 (Look AHEAD); NCT01410097 (Look AHEAD ancillary); NCT00116194 (LIFE).

The Association Between Gait Speed and Sleep Problems Among Chinese Adults Aged 50 and Greater

Objective

The relationship between sleep problems and walking speed has been less explored. The present cross-sectional study was to investigate the association between sleep quality and sleep duration and gait speed in Chinese adults.

Methods

A total of 13,367 participants were recruited in this cross-sectional study, retrieving the data from the Global Aging and Adult Health Survey (SAGE). Gait speed was measured using the 4-m walking test. Age, sex, education years, smoking status, alcohol consumption, physical activity, chronic disease, sleep problems were self-reported by participants. To explore the association between sleep problems and gait speed, multivariate linear regression models were employed.

Results

In the adjusted model, poor sleep quality and longer sleep duration were significantly associated with slower normal walking speed in Chinese adults (p &lt; 0.001). Moreover, there were negatively significant associations between normal gait speed and sleep quality in male adults (p &lt; 0.01).

Conclusion

The findings suggest that slower normal walking speed was associated with poor sleep quality and longer sleep duration (&gt;8 h) in Chinese male adults.

Fear of Falling Does Not Influence Dual-Task Gait Costs in People with Parkinson's Disease: A Cross-Sectional Study

Cognitive deficits and fear of falling (FOF) can both influence gait patterns in Parkinson’s disease (PD). While cognitive deficits contribute to gait changes under dual-task (DT) conditions, it is unclear if FOF also influences changes to gait while performing a cognitive task. Here, we aimed to explore the association between FOF and DT costs in PD, we additionally describe associations between FOF, cognition, and gait parameters under single-task and DT. In 40 PD patients, motor symptoms (MDS-revised version of the Unified Parkinson’s Disease Rating Scale, Hoehn and Yahr), FOF (Falls Efficacy Scale International), and Montreal Cognitive Assessment (MoCA) were assessed. Spatiotemporal gait parameters were recorded with a validated mobile gait analysis system with inertial measurement units at each foot while patients walked in a 50 m hallway at their preferred speed under single-task and DT conditions. Under single-task conditions, stride length (β = 0.798) and spatial variability (β = 0.202) were associated with FOF (adjusted R2 = 0.19, p < 0.001) while the MoCA was only weakly associated with temporal variability (adjusted R2 = 0.05, p < 0.001). Under DT conditions, speed, stride length, and cadence decreased, while spatial variability, temporal variability, and stride duration increased with the largest effect size for speed. DT costs of stride length (β = 0.42) and age (β = 0.58) explained 18% of the MoCA variance. However, FOF was not associated with the DT costs of gait parameters. Gait difficulties in PD may exacerbate when cognitive tasks are added during walking. However, FOF does not appear to have a relevant effect on dual-task costs of gait.

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.

Predictors of Future Walking Speed: A 12-Month Monitoring Program

The purpose of the current study was to identify significant predictors of walking speed (WS) among community-dwelling older adults, as it is one of the most representative measures of functioning in their daily lives. Seventy-seven (24 adult men, 26 adult women, and 27 older-adult women) community-dwelling older adults (73.7 ± 4.9 years) performed two assessments, over a 12-month period. Several physical, cognitive, and psychological tests were performed, as well as assessing the preferred WS. Multiple linear regression, stratified by gender, was used to identify significant predictors of future WS. For the adult men, walking and functional performances at the first assessment predicted 71.9%; for adult women, reaction time, walking, and balance performance predicted 64.4%; and, for the older-adult women, fast walking and reaction time predicted 48.2% of the variance of future WS. Clinicians should consider including different exercises for each group of older adults to evaluate and preserve functional abilities.

Single-Task or Dual-Task? Gait Assessment as a Potential Diagnostic Tool for Alzheimer's Dementia

Background:

A person’s gait performance requires the integration of sensorimotor and cognitive systems. Therefore, a person’s gait may be influenced by concurrent cognitive load such as simultaneous talking. Although it has been known that gait performance of people with Alzheimer’s dementia (AD) is compromised when they attempt a dual-task walking task, it is unclear if using a dual-task gait performance during an AD assessment yields higher diagnostic accuracy.

Objective:

This study was designed to compare the predictive power for AD of dual-task gait performance in an AD assessment to that of single-task gait performance.

Methods:

Participants (14 with AD and 15 healthy controls) walked across the GAITRite© Portable Walkway mat under three different cognitive load conditions: no simultaneous cognitive load, walking while counting numbers by ones, and walking while completing category naming.

Results:

Multiple logistic regression revealed that the gait performance under a dual-task condition (i.e., concurrent counting or category naming) increased the proportion of variance explained by the FAP, SL, and DST, of the incidence of AD.

Conclusion:

Dual-task walking and talking may be a more effective diagnostic feature than single-task walking in a comprehensive AD diagnostic assessment.

Impact of different bilateral knee extension strengths on lower extremity performance

Despite the impact of leg muscle strength on lower extremity motor performance-including walking and sit-to-stand transfer-it remains difficult to predict the relationship between bilateral leg muscle strength and lower extremity performance. Therefore, this study was designed to predict lower extremity function through the differential modeling of logarithmic and linear regression, based on knee extension strength.The study included 121 individuals living in the same community. The bilateral strengths of the knee extensors were measured using a handheld dynamometer, and the Timed Up & Go test (TUG) performance time and 5-m minimum walking times were assessed to predict lower extremity motor functions. Bilateral normalized knee extension muscle strengths and lower extremity motor function scores, including walking or TUG performance times, were assessed on the logarithmic and linear models. The Akaike information criterion (AIC) was used to evaluate the coefficient compatibility between the logarithmic regression model and the linear regression model.The AIC value for the linear model was lower than that for the logarithmic model regarding the walking time. For walking time estimation in the linear model, the coefficient value of knee extension strength was larger on the strong than on the weak side; however, the AIC value for the logarithmic model was lower than that for the linear model regarding TUG performance time. In the logarithmic model's TUG performance time estimation, the coefficient value of knee extension strength was larger on the weak than on the strong side.In conclusion, our study demonstrated different models reflecting the relationship between both legs' strengths and lower extremity performance, including the walking and TUG performance times.

Effects of Exergame-Based Dual-Task Training on Executive Function and Dual-Task Performance in Community-Dwelling Older People: A Randomized-Controlled Trial

Objective: Aging is associated with decline in executive function that may lead to reduced dual-task performance. Regular exercise has been recommended for promoting or maintaining mental and physical health in older adults, yet only a fraction of older adults exercise regularly. Exergame training may have the potential to enhance exercise adherence. Therefore, the aim of this study was to examine the effects of exergame-based dual-task training on executive function and dual-task performance in community-dwelling older adults. Materials and Methods: This was a single-blinded, randomized-controlled trial. Twenty community-dwelling older adults were recruited and randomly assigned to one of two groups. All participants completed 36 trainings, including three 60-minute sessions/week over 12 weeks. Participants in the experimental group received exergame-based dual-task training, while those in the control group received home-based multicomponent exercise training. Measures of executive function, dual-task performance, and community walking ability were assessed before and after the intervention. Results: Significant group × time interactions (P = 0.000-0.027) with large effects were found in all selected outcome measures. Compared with the control group, the experimental group improved significantly in measures of general executive function (P = 0.014), inhibitory control (P = 0.037), cognitive dual-task performance (P < 0.001), and community walking ability (P = 0.002). Enhanced general executive function was highly correlated with either improved motor dual-task performance (r = 0.674) or improved cognitive dual-task performance (r = -0.701). Conclusion: These results suggested that exergame-based dual-task training improved both executive function and dual-task performance in older people. These positive effects could be transferred to enhance community walking ability. Clinical Trial Registration number: ACTRN 12617000095369.

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

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

Signatures of Gait Movement Variability in CKD Patients Scheduled for Hemodialysis Indicate Pathological Performance Before and After Hemodialysis: A Prospective, Observational Study

Background: The frailty status of hemodialysis patients is well-known, but the role of the therapy in the frailty process is not yet clear. Nowadays gait analysis in nephrology is neglected, although gait performance is known to be related to frailty and kidney function. We hypothesized that gait quality and physical activity level is already affected before, and does not change because of the start of hemodialysis.

Methods: Fourteen patients (72.3 ± 5.7 years old) in a pre-dialysis program underwent an instrumental gait analysis and their physical activity was monitored for a week. This protocol was repeated 3, 6, 12, and 24 months after the first hemodialysis session.

Results: At baseline, our sample showed a conservative gait with pathologic gait variability, high dual-task cost, and a sedentary lifestyle. No statistically significant change was found in any parameter in the analyzed period, but there was a tendency toward an improvement of gait quality and physical activity in the first year of treatment, and a decline in the second year.

Conclusion: Elderly patients in the pre-dialysis stage show a conservative gait, however variability was in a pathological range and did not change post-hemodialysis. This hints toward changes in the central nervous system due to the kidney disease. This finding suggests the importance of gait analysis in the early stages of renal disease in the diagnosis of changes in the nervous system due to kidney failure that affect gait. Early detection of these changes would potentially allow a prevention program tailored to this population to be developed.

Using hand grip strength to detect slow walking speed in older adults: the Yilan study

Background

Walking speed is an important health indicator in older adults, although its measurement can be challenging because of the functional decline due to aging and limited environment. The aim of this study was to examine whether hand grip strength can be a useful proxy for detecting slow walking speed in this population.

Methods

A cross-sectional study was conducted using the cohort from the Yilan Study in Taiwan. Community-dwelling older adults aged 65 years and older were included. Slow walking speed was defined as a 6-meter walking speed < 1.0 m/s, according to the 2019 Asian Working Group for Sarcopenia diagnostic criteria. Stepwise multiple linear regression was used to determine the most significant variables associated with walking speed. Receiver operating characteristic analysis was used to determine the optimal cutoff values for hand grip strength in detecting slow walking speed.

Results

A total of 301 participants with an average age of 73.9 ± 6.8 years were included; 55.1 % participants were women. In stepwise multiple linear regression analysis that included various variables, hand grip strength was found to be the most explainable factor associated with walking speed among all participants and among participants of each sex. The optimal cutoff values for hand grip strength in the detection of slow walking speed were 19.73 kg for all participants (sensitivity: 55 %, specificity: 83 %, area under the curve: 0.74, accuracy: 66.9 %), 35.10 kg for men (sensitivity: 92 %, specificity: 42 %, area under the curve: 0.70, accuracy: 66.4 %), and 17.93 kg for women (sensitivity: 62 %, specificity: 80 %, area under the curve: 0.76, accuracy: 67.9 %).

Conclusions

Hand grip strength was found to be a useful proxy for the identification of slow walking speed in older adults.

Trajectories of Cognitive and Motor Function Between Ages 45 and 90 Years: A Population-Based Study

Background

To establish trajectories of cognitive and motor function, and to determine the sequence of change across individual tests in community-dwelling individuals aged 45–90 years.

Method

Between 1997 and 2016, we repeatedly assessed cognitive function with 5 tests in 9514 participants aged 45–90 years from the population-based Rotterdam Study. Between 1999 and 2016, we measured motor function with 3 tests in 8297 participants. All participants were free from dementia, stroke, and parkinsonism. We assessed overall and education-specific cognitive and motor trajectories using linear mixed models with age as time scale. Next, we determined the sequence of change across individual tests.

Results

The number of assessments per participant ranged between 1 and 6 (mean interval, years [SD]: 5.1 [1.4]) for cognitive function, and 1 and 4 (5.4 [1.4]) for motor function. Cognitive and motor trajectories declined linearly between ages 45 and 65 years, followed by steeper declines after ages 65–70 years. Lower educated participants had lower cognitive function at age 45 years (baseline), and declined faster on most cognitive, but not on motor tests than higher educated participants. Up to a 25-year age difference between the fastest and slowest declining test scores was observed.

Conclusions

On a population-level, cognitive and motor function decline similarly. Compared to higher educated individuals, lower educated individuals had lower cognitive function at baseline, and a faster rate of decline thereafter. These educational-effects were not seen for motor function. These findings benefit the understanding of the natural course of cognitive and motor function during aging, and highlight the role of education in the preservation of cognitive but not motor function.

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.

Relations of Executive Function and Physical Performance in Middle Adulthood: A Prospective Investigation in African American and White Adults

OBJECTIVES

Previous studies in older adults found robust associations between executive functions (EF) and physical performance, as well as sociodemographic variation in physical performance decline. To examine these associations earlier in the adult lifespan, we investigated relations of EF, race, and sex with age-related physical performance decline during middle adulthood.

METHOD

Participants were 2,084 urban-dwelling adults (57.2% female; 57.8% African American; 37.3% living in poverty; mean baseline age = 48.1) from the Healthy Aging in Neighborhoods of Diversity across the Life Span study. Mixed-effects regression was used to examine interactive relations among EF, race, sex, and age (indexing time) with change in dominant and nondominant handgrip strength and lower extremity strength over approximately 5 years. All analyses adjusted for poverty status, and subsequently adjusted for education, body mass index, hypertension, and diabetes.

RESULTS

There were no significant prospective associations between EF and decline in physical performance measures. Significant cross-sectional associations revealed that lower EF was associated with worse performance on all physical performance measures averaged across both time points (p < .05). A significant two-way interaction of Sex × Age (p = .019) revealed that men experienced greater age-related decline in lower extremity strength than women.

DISCUSSION

Findings did not reveal prospective associations between EF and physical performance decline in middle adulthood. However, they identified robust cross-sectional associations between EF and physical performance, and unexpectedly greater decline in lower extremity strength in men than women. Ultimately, these findings may inform prevention and intervention strategies targeting groups at risk for poorer physical function status and decline.

Integrating Three Characteristics of Executive Function in Non-Demented Aging: Trajectories, Classification, and Biomarker Predictors

OBJECTIVE

With longitudinal executive function (EF) data from the Victoria Longitudinal Study, we investigated three research goals pertaining to key characteristics of EF in non-demented aging: (a) examining variability in EF longitudinal trajectories, (b) establishing trajectory classes, and (c) identifying biomarker predictors discriminating these classes.

METHOD

We used a trajectory analyses sample (n = 781; M age = 71.42) for the first and second goals and a prediction analyses sample (n = 570; M age = 70.10) for the third goal. Eight neuropsychological EF measures were used as indicators of three EF dimensions: inhibition, updating, and shifting. Data-driven classification analyses were applied to the full trajectory distribution. Machine learning prediction analyses tested 15 predictors from genetic, functional, lifestyle, mobility, and demographic risk domains.

RESULTS

First, we observed: (a) significant variability in EF trajectories over a 40-year band of aging and (b) significantly variable patterns of EF decline. Second, a four-class EF trajectory model was observed, characterized with classes differentiated by an algorithm of level and slope information. Third, the highest group class was discriminated from lowest by several prediction factors: more education, more novel cognitive activity, lower pulse pressure, younger age, faster gait, lower body mass index, and better balance.

CONCLUSION

First, with longitudinal variability in EF aging, the data-driven approach showed that long-term trajectories can be differentiated into separable classes. Second, prediction analyses discriminated class membership by a combination of multiple biomarkers from demographic, lifestyle, functional, and mobility domains of risk for brain and cognitive aging decline.

Metabolic Syndrome and Physical Performance: The Moderating Role of Cognition among Middle-to-Older-Aged Adults

OBJECTIVE

Mobility limitation and cognitive decline are related. Metabolic syndrome (MetS), the clustering of three or more cardiovascular risk factors, is associated with decline in both mobility and cognition. However, the interrelationship among MetS, mobility, and cognition is unknown. This study investigated a proposed pathway where cognition moderates the relationship between MetS and Mobility.

METHOD

Adults ages 45-90 years were recruited. MetS risk factors and mobility performance (Short Physical Performance Battery (SPPB) and gait speed) were evaluated. Cognition was assessed using a comprehensive neuropsychological battery. A factor analysis of neuropsychological test scores yielded three factors: executive function, explicit memory, and semantic/contextual memory. Multivariable linear regression models were used to examine the relationship among MetS, mobility, and cognition.

RESULTS

Of the 74 participants (average age 61 ± 9 years; 41% female; 69% White), 27 (36%) participants manifested MetS. Mean SPPB score was 10.9 ± 1.2 out of 12 and gait speed was 1.0 ± 0.2 m/s. There were no statistically significant differences in mobility by MetS status. However, increase in any one of the MetS risk factors was associated with decreased mobility performance after adjusting for age and gender (SPPB score: β (SE) -.17 (0.08), p < .05; gait speed: -.03 (.01), p < .01). Further adjusting for cognitive factors (SPPB score: explicit memory .31 (.14), p = .03; executive function 0.45 (0.13), p < .01; gait speed: explicit memory 0.04 (0.02), p = .03; executive function 0.06 (0.02), p < .01) moderated the relationships between number of metabolic risk factors and mobility.

CONCLUSION

The relationship between metabolic risk factors and mobility may be moderated by cognitive performance, specifically through executive function and explicit memory.

Effect of chronic alcohol intake on motor functions on the elderly

Alcohol use disorder (AUD) is a chronic and progressive disease influenced by genetic, psychosocial, and environmental factors. The consequences of alcohol consumption involve alterations in neural circuits of emotion and cognition, as well as in the motor planning circuit. Furthermore, during the natural aging process, several biochemical and functional alterations are also observed with neurological consequences. Thus, considering the consequences of chronic alcohol consumption on neural systems and natural aging process, we aimed to analyze the degree of motor and functional impairment in elderly with chronic alcohol consumption. Sixty elderly underwent an analysis of alcohol consumption profile (Alcohol Use Disorders Identification Test - AUDIT) that divided them into a control group (CON) and an alcohol group (ALC). The analysis of quality of life was performed using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), the analysis of motor function was performed using the Borg Scale, the Six-Minute Walk Test (6MWT) and the Motor Scale for Elderly (MSE). We were able to conclude that the misuse of alcohol by the elderly promotes significant physical limitations. These limitations result in a worsening of functional capacity of walking and various dimensions of motor ability: fine motor skill, global coordination, balance, body scheme, spatial organization, temporal organization, and general motor aptitude. Besides the physical limitations caused by alcohol use, the quality of life in their physical, mental, and social aspects was reduced. Thus, actions are required to help the elderly understand these losses and exercise control over alcohol misuse.

Do cognitive performance and physical function differ between individuals with motoric cognitive risk syndrome and those with mild cognitive impairment?

BACKGROUND

Motoric cognitive risk syndrome (MCR) is defined by slow gait speed combined with subjective cognitive complaint. MCR is a predementia syndrome, similar to mild cognitive impairment (MCI). However, there is currently no study comparing the differences in cognitive performance and physical function between these two types of cognitive impairment. Thus, the aim of this study is to compare cognitive performance and physical function in individuals with MCR versus MCI.

METHODS

A total of 77 participants, free of dementia, were recruited from the neurological outpatient clinic of a medical center in Taiwan. Participants were separated into 2 groups, MCR (n = 33) and MCI (n = 44) groups, based on definition criteria from previous studies. The priority was to assign a diagnosis of MCR first, followed by MCI. Hence, "pure" MCI had no overlap with MCR syndrome. Cognitive performance, including executive function, attention, working memory, episode memory, visuospatial function, and language, were measured. Physical functions such as activities in daily living, the Tinetti Assessment Scale, and the Timed Up and Go test were also measured.

RESULTS

Executive function, attention, working memory, episodic memory and language were all significantly lower in the MCR group than the MCI group. Abilities related to physical function, including those measured by the Tinetti Assessment Scale and the Timed Up and Go test, were significantly lower in the MCR group than the MCI group.

CONCLUSIONS

We noted that cognitive performance and physical function were lower in MCR individuals than MCI but without MCR syndrome. However, the conclusions were based on the enrollment procedure of participants prioritizes the MCR syndrome. Because of the overlap of MCR and MCI, future studies should use different enrollment strategies to further clarify the status of these two populations.

Cognitive decline negatively impacts physical function

Many older adults report difficulty performing one or more activities of daily living. These difficulties may be attributed to cognitive decline and as a result, measuring cognitive status among aging adults may help provide an understanding of current functional status. The purpose of the present investigation was to determine the association between cognitive status and measures of physical functioning. Seventy-six older adults participated in this study; 41 were categorized as normal memory function (NM) and 35 were poor memory function (PM). NM participants had significantly higher physical function as measured by Short Physical Performance Battery (SPPB; 9.4 ± 2.2 vs. 8.4 ± 2.0; p = .03) and peak velocity (0.67 ± 0.16 vs. 0.56 ± 0.19; p = .04) during a quick sit-to-stand task. Dual-task walking velocities were 22% and 126% slower between cognitive groups for the fast and habitual trials, respectively when compared to the single-task walking condition. Significant correlations existed between measures of memory and physical function. The largest correlations with memory were for peak (r = 0.42) and average (r = 0.38) velocity. The results suggest a positive relationship between physical function and cognitive status. However, further research is needed to determine the mechanism of the underlying relationships between physical and cognitive function.

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.

Changes in Physical Functioning as Short-Term Predictors of Mortality

OBJECTIVES

Both performance-based and self-reported measures of physical functioning are predictors of mortality. There has been relatively little research examining whether their changes predict mortality. This study examines whether 5-year changes in performance-based and self-reported measures of functioning predict subsequent mortality.

METHOD

Data are from the 2006 wave of the Social Environment and Biomarkers of Aging Study, 2011 wave of the Taiwan Longitudinal Study of Aging, and mortality follow-up through 2015. Gompertz proportional hazard models predict mortality from changes in ability to complete performance-based tests and changes in performance-based and self-reported functioning.

RESULTS

Incident inability to complete at least one performance-based test of functioning is associated with twice the risk of subsequent 4-year mortality. Conditional on the baseline measurement, a one standard deviation (SD) decline in grip strength is associated with a 61% increased risk of 4-year mortality; a one-SD decline in walking speed and a one-SD increase in self-reported limitations are both associated with around a 40% increased risk of 4-year mortality. Conditional on the most recent measurement of functioning, prior change is not significantly associated with subsequent mortality.

DISCUSSION

Repeated measures of performance-based and self-reported functioning are valuable in that they provide an updated measurement of functioning.

Executive Functions Are Associated with Fall Risk but not Balance in Chronic Cerebrovascular Disease

BACKGROUND

Older people's deficits in executive functions (EF) have been shown to lead to higher fall risk, postural sway, and reduced speed. Crucially, EF impairments are even more pronounced in individuals with chronic cerebrovascular disease (CVD), namely vascular cognitive impairment.

METHODS

In this retrospective cross-sectional study, we used a complete neuropsychological battery, including the Trail Making Test (TMT) and physical measures, such as the Morse fall and EQUI scales, to assess 66 individuals with chronic CVD. Linear regressions, Bayesian analyses, and model selection were performed to see the impact of EF, global cognition, and vascular parkinsonism/hemiplegia on physical measures (fall risk and balance).

RESULTS

The TMT part B and BA correlated (r = 0.44 and r = 0.45) with Morse fall scale. Only EF significantly explained fall risk, whereas global cognition and vascular parkinsonism/hemiplegia did not. These findings were confirmed by Bayesian evidence and parsimony model selection. Balance was not significantly correlated with any of the neuropsychological tests.

CONCLUSIONS

This is the first study investigating the relationship between cognitive and physical measures in a sample of older people with chronic CVD. The results are consistent with previous findings that link EF with fall risk in CVD.

Long-Term Running Exercise Delays Age-Related Changes in White Matter in Rats

Running exercise, one of the strategies to protect brain function, has positive effects on neurons and synapses in the cortex and hippocampus. However, white matter, as an important structure of the brain, is often overlooked, and the effects of long-term running exercise on white matter are unknown. Here, 14-month-old male Sprague–Dawley (SD) rats were divided into a middle-aged control group (18-month-old control group), an old control group (28-month-old control group), and a long-term runner group (28-month-old runner group). The rats in the runner group underwent a 14-month running exercise regime. Spatial learning ability was tested using the Morris water maze, and white matter volume, myelinated fiber parameters, total mature oligodendrocyte number, and white matter capillary parameters were investigated using stereological methods. The levels of growth factors related to nerve growth and vascular growth in peripheral blood and the level of neurite outgrowth inhibitor-A (Nogo-A) in white matter were measured using an enzyme-linked immunosorbent assay (ELISA). The present results indicated that long-term running exercise effectively delayed the age-related decline in spatial learning ability and the atrophy of white matter by protecting against age-related changes in myelinated fibers and oligodendrocytes in the white matter. Moreover, long-term running exercise prevented age-related changes in capillaries within white matter, which might be related to the protective effects of long-term exercise on aged white matter.

Are Cognitive Subtypes Associated with Dual-Task Gait Performance in a Clinical Setting?

BACKGROUND

Poor dual-task gait (walking while performing a cognitively demanding task) has been linked to progression to dementia in older adults with mild cognitive impairment (MCI). However, many of these findings come from research environments; gait performance across the cognitive spectrum has not previously been studied in a clinical setting.

OBJECTIVE

To examine whether patients from a memory clinic show differences in usual and dual-task gait speed and dual-task cost (DTC) based on cognitive diagnosis.

METHODS

Patients in the Aging Brain and Memory Clinic (London, ON) performed a usual gait walk and three dual-task gait walks: counting backwards by ones, naming animals, and counting backwards by seven (serial sevens) out loud. Patients were timed with a stopwatch over a six-meter path marked on the floor. One-way ANOVA was performed to evaluate associations between gait speed and DTC (%) across groups.

RESULTS

One hundred ninety-four patients with subjective cognitive impairment (SCI; n = 46), MCI (n = 77), or dementia (n = 71) were assessed. Performance in usual (p < 0.001) and dual-task gait speed (counting gait p < 0.001; naming animals p < 0.001; serial sevens p = 0.004) decreased across the spectrum of cognitive impairment. Patients with dementia had significantly higher DTC in both counting gait (p = 0.02) and naming animals (p = 0.04) conditions compared with patients with SCI and MCI, who had statistically similar DTC in all conditions.

CONCLUSION

Dual-task gait performance significantly declines across the cognitive spectrum in a clinical setting. Dual-task gait testing may be used in conjunction with traditional assessments for diagnosing cognitive impairments.