Aging, the central nervous system, and mobility

Immediate effects of visual feedback on the accuracy of foot landing adjustments in older people with diabetes mellitus: A cross-sectional study

Diabetes Mellitus in older adults reduces the accuracy of foot landing adjustments and increases the risk of falling. This study investigated whether targeted visual feedback enhances the accuracy of the foot landing in older participants with diabetes. Forty-eight volunteers in three groups of young, healthy older and older adults with diabetes participated. During treadmill walking, Nexus Vicon software streamed real-time orientation data of two markers on the first toes into MATLAB scripts through a Visual3D server. The system visualised real-meaningful step length or minimum toe clearance (MTC) in each step on a monitor in front of a treadmill at eye level. Participants responded to four subject-specific step-length (±10% mean baseline step length) or MTC targets (3.5 and 5.5 cm higher than the mean baseline MTC). One target was displayed every 10 steps and removed after 10 steps when participants walked without seeing any target, then a new or the same target appeared and stayed on for another 10 steps. Tasks were increasing or decreasing baseline step length or increasing the baseline MTC in response to virtual targets. The accuracy (absolute error) of each step adjustment in each 10-step block with a target was calculated. The mean accuracy of Step 1 and the mean accuracy of Steps 2-10 were measured and compared within and between groups using three-way ANOVA tests. Errors significantly differed between conditions (Step 1 and Steps 2-10) in all groups. All groups showed reduced errors in Step 1 during Steps 2-10. Among groups, the group with diabetes presented the greatest errors in Step 1 and Steps 2-10. These findings suggest that meaningful visual feedback about spatial gait parameters (step length, MTC) can improve foot-landing accuracy in older participants with diabetes, highlighting its potential as a training tool to prevent falls in this high-risk population.

What determines gait speed in community-living older adults? A relative weight analysis

PURPOSE

Slower gait is prevalent in older adults. Multiple factors contribute to the slowness in older adults. However, whether these factors affect gait speed similarly or differently remains unknown. The primary purpose of this study was to explore the relative importance of eight modifiable factors (body mass index, leg muscle strength, power, dorsiflexion range of motion, tactile sensation, balance, fear of falling, and cognition) affecting gait speed in community-living older adults.

METHODS

Eighty-five community-living older adults (mean ± standard deviation age: 72.3 ± 5.5 years; 51 females and 34 males) were enrolled in this cross-sectional study. A motion capture system assessed their gait speed. Those eight factors that could slow gait speed in older adults were also evaluated. A multiple linear regression model and relative weight analysis were utilized to determine the relative importance of each factor in contributing to the gait speed variation.

RESULTS

All eight factors were significantly correlated with the gait speed. Together, they accounted for about 50% of the observed variation in gait speed. Six factors (body mass index, strength, power, range of motion, balance, and fear of falling) each explained a statistically significant portion of the gait speed variation. The most important factor was the leg muscle power (relative weight = 0.124), contributing 25.2% of the explained speed variation.

CONCLUSION

Leg muscle power could be a principal factor determining gait speed in older adults. Other factors also significantly influence gait speed in this population. The findings could guide prioritizing actions to improve gait speed in older individuals.

Nigrostriatal dopaminergic integrity in relation to prefrontal cortex activity and gait performance during dual-task walking in older adults

Greater walking automaticity facilitates maintenance of gait speed without prefrontal cortex (PFC) resources. Brain aging may cause shifts to more attentional gait with greater engagement of the PFC. Nigrostriatal dopaminergic integrity likely facilitates walking automaticity and maintenance of gait speed during attentional dual-tasks. Older adults (n=201; age=74.9; 63.2% women, gait speed=1.10 m/s) completed a dual-task protocol of saying every other letter of the alphabet while walking. PFC activation was measured by functional near-infrared spectroscopy. Four groups were defined based on PFC activation (increased during dual-task, PFC+, or not, PFC-) and gait speed performance (maintained during dual-task, gait+, or slowed, gait-). To compare nigrostriatal dopaminergic integrity across groups, we assessed binding of the type-2 vesicular monoamine transporter (VMAT2) density in the sensorimotor and associative striatum using [11C]-(+)-α-dihydrotetrabenazine (DTBZ) positron emission tomography. Multinomial regression estimated adjusted associations of DTBZ binding with group membership. We hypothesized that DTBZ binding was highest for those who maintained gait speed without additional PFC activation when switching from single- to dual-task (PFC-/gait+; i.e., highest gait automaticity). In bivariate analyses, the PFC-/gait+ group had the highest DTBZ binding in the sensorimotor striatum (p=0.05); binding in the associative striatum was similar across groups (p=0.1). Results were similar in adjusted regression analyses; DTBZ binding in sensorimotor striatum was associated with lower likelihood to be in the PFC-/gait- (OR=0.28; 95% CI: 0.08, 0.94) or the PFC+/gait+ (OR=0.29; 95% CI: 0.10, 0.84) groups compared to PFC-/gait+ reference group. These results provide support for dopaminergic involvement in sustaining gait automaticity at older ages.

Association between education and walking speed: counterfactual mediation analysis in favor of a motor reserve hypothesis

We quantified the extent to which the association between education and fast walking speed (FWS) is explained by 17 mediators (cardiovascular risk factors/diseases, comorbidities, health behaviors, socioprofessional characteristics, cognition), and examined whether mediators interact with education, in favor of a reserve hypothesis. Cross-sectional analyses are based on Constances (a population-based study of French adults 45-69 years). Three-meter FWS was measured using photoelectric cells. Education was categorized as lower vs higher. After multiple imputation of missing values, we used counterfactual mediation models for multiple mediators allowing for education × mediator interactions, to estimate the total effect (TE), total indirect effect (TIE), and mediated interaction (IMD) of lower education on FWS. Analyses are based on 71 222 participants (52.6% women; mean age = 57.2 years; 27.2% higher education; mean FWS = 180.2 cm/s). In joint mediation analyses, the TE of lower education was -8.19 cm/s (95% CI, -8.87 to -7.51), with a TIE of -5.76 cm/s (95% CI, -6.10 to -5.41; proportion mediated = 70.3%; 95% CI, 65.6-75.0). The IMD was negative (-2.52; 95% CI, -3.31 to -1.72); 30.8% of the TE and 43.8% of the TIE were attributable to the IMD. Several mediators explain a large part of the association between lower education and slower FWS. The detrimental effect of mediators was more pronounced in participants with lower than in those with higher education, in agreement with a reserve hypothesis.

Mapping the neural substrate of high dual-task gait cost in older adults across the cognitive spectrum

The dual task cost of gait (DTC) is an accessible and cost-effective test that can help identify individuals with cognitive decline and dementia. However, its neural substrate has not been widely described. This study aims to investigate the neural substrate of the high DTC in older adults across the spectrum of cognitive decline. A total of 336 individuals from the GAIT study cohort were analyzed, including cognitively healthy (N = 122, 71 ± 3.6 years), those with mild cognitive impairment (N = 168, 71 ± 5.3 years), and those with dementia (N = 46, 80 ± 5.7 years). A DTC of 20% or greater was considered to indicate a high level of slowing down while performing successively two verbal tasks (counting backwards task by ones and naming animals). Voxel-based morphometry was employed to investigate differences in gray matter volume (GMV) between groups, which were dichotomized according to the DTC. A high DTC in the whole population (N = 336) was associated with a smaller GMV in the bilateral temporal lobe across both dual-task conditions. A moderation analysis was employed to compare the neural substrate between cognitive status groups. This revealed that the dementia group exhibited an additional cluster located in the left precentral gyrus with GMV loss associated with a high naming animals DTC, in contrast to the other cognitive groups. These results provide new evidence on why dual-task gait capabilities deteriorate in normal and pathological cognitive aging. A more precise understanding of the neural substrate associated with high DTC and cognitive status would help elucidate its use in clinical and research settings.

An association of cognitive function with mobile metrics of community walking in older cancer survivors: A pilot study

INTRODUCTION

Older cancer survivors have an elevated risk for mobility dysfunction compared to their cancer-free peers. Despite the established link between cognitive function and community walking in older cancer-free adults, little is known about this relationship in older cancer survivors. This pilot study aimed to evaluate the association of performance-based and self-reported cognitive function with mobile metrics of community walking collected by a wearable Fitbit device.

MATERIALS AND METHODS

This study enrolled older cancer survivors (mean age 73 years old, range 65-83; 98 % White; 50 % female) within five years of completing primary treatment. Cognitive function, specifically executive function and processing speed was collected with the digit symbol substitution test (DSST) and self-reported cognition was evaluated by the Patient Reported Outcomes Measurement Information System- Cognitive (PROMIS-Cog). Continuous walking data from Fitbit wearable devices were collected passively over four weeks. To examine associations between DSST and PROMIS-Cog with mobile measures of walking, we conducted bivariate correlation and multivariable linear regression analyses adjusting for age, education, and number of comorbidities.

RESULTS

In bivariate analyses, higher DSST scores were correlated with higher step count and peak cadence and lower fragmentation of walking in daily life (r = 0.48-0.51, p < 0.01). Higher PROMIS-Cog scores were correlated with higher peak cadence (r = 0.32, p < 0.05), trended towards correlation with step count (r = 0.30, p = 0.06), and were not correlated with fragmentation of walking (r = -0.24, p = 0.13). In multivariable models adjusting for age, presence of graduate level education, and number of comorbidities, higher DSST scores were independently associated with higher peak cadence, step count, and demonstrated a trend towards lower fragmentation of walking in daily life, but PROMIS-Cog was not independently associated with any mobility metrics. Similar results for association of DSST with walking when models included adjustment for PROMIS-depression scale, receipt of chemotherapy treatment, or when education was defined by presence of a bachelor's degree.

DISCUSSION

This study suggests an association between cognitive functions of executive function and processing speed with mobile metrics of community walking in older cancer survivors. Understanding how cognitive function affects walking may help identify new rehabilitation targets for older cancer survivors.

Gait performance in older adults across the cognitive spectrum: Results from the GAIT cohort

BACKGROUND

Gait performance can provide valuable insights into cognitive functioning in older adult and may be used to screen for cognitive impairment. However, the optimal test condition and spatiotemporal parameter for accuracy have not yet been determined. This study aims to determine the gait measure with the highest accuracy identifying cognitive decline.

METHODS

A total of 711 participants were recruited, including 332 cognitively healthy individuals, 264 with mild cognitive impairment (MCI), and 115 with dementia, with a mean age of 72 years (interquartile range 69-76), and 43% (n = 307) of women. The participants underwent gait assessment in three different conditions, including a single task and dual tasks of counting backward by ones and naming animals.

RESULTS

Gait performance was deteriorated as cognitive impairment progressed. The gait test performed during naming animals condition was the most accurate in differentiating between cognitive groups. Specifically, the naming animals gait speed was more accurate in discriminating control participants from those with cognitive impairment (area under the curve [AUC] = 76.9% for MCI and 99.7% for people with dementia with control group as reference). The coefficient of stride length variability while naming animals was the most effective parameter in discriminating between MCI and dementia groups (AUC = 96.7%).

CONCLUSIONS

The naming animals dual-task gait test can be a valuable assessment for screening cognitive impairment in older adults, regardless of their cognitive abilities. The test is useful in clinical settings for subjects with a range of cognitive profiles.

Association of physical function with connectivity in the sensorimotor and dorsal attention networks: why examining specific components of physical function matters

Declining physical function with aging is associated with structural and functional brain network organization. Gaining a greater understanding of network associations may be useful for targeting interventions that are designed to slow or prevent such decline. Our previous work demonstrated that the Short Physical Performance Battery (eSPPB) score and body mass index (BMI) exhibited a statistical interaction in their associations with connectivity in the sensorimotor cortex (SMN) and the dorsal attention network (DAN). The current study examined if components of the eSPPB have unique associations with these brain networks. Functional magnetic resonance imaging was performed on 192 participants in the BNET study, a longitudinal and observational trial of community-dwelling adults aged 70 or older. Functional brain networks were generated for resting state and during a motor imagery task. Regression analyses were performed between eSPPB component scores (gait speed, complex gait speed, static balance, and lower extremity strength) and BMI with SMN and DAN connectivity. Gait speed, complex gait speed, and lower extremity strength significantly interacted with BMI in their association with SMN at rest. Gait speed and complex gait speed were interacted with BMI in the DAN at rest while complex gait speed, static balance, and lower extremity strength interacted with BMI in the DAN during motor imagery. Results demonstrate that different components of physical function, such as balance or gait speed and BMI, are associated with unique aspects of brain network organization. Gaining a greater mechanistic understanding of the associations between low physical function, body mass, and brain physiology may lead to the development of treatments that not only target specific physical function limitations but also specific brain networks.

Cognitive reserve proxies are associated with age-related cognitive decline - Not age-related gait speed decline

Cognition and gait share brain substrates in aging and dementia. Cognitive reserve (CR) allows individuals to cope with brain pathology and delay cognitive impairment and dementia. Yet, evidence for that CR is associated with age-related cognitive decline is mixed, and evidence for that CR is associated with age-related gait decline is limited. In 1,079 older (M Age = 75.4 years; 56.0% women) LonGenity study participants without dementia at baseline and up to 12 years of annual follow-up (M follow-up = 3.9 years, SD = 2.5 years), high CR inferred from cognitive (education years), physical (number of blocks walked per day; weekly physical activity days), and social (volunteering/working; living with someone) proxies were associated with slower rates of age-related decline in global cognition - not gait speed decline. Thus, cognitive, physical, and social CR proxies are associated with cognitive decline in older adults without dementia. The multifactorial etiology and earlier decline in gait than cognition may render it less modifiable by CR proxies later in life.

Neural underpinnings of fine motor skills under stress and anxiety: A review

This review offers a comprehensive examination of how stress and anxiety affect motor behavior, particularly focusing on fine motor skills and gait adaptability. We explore the role of several neurochemicals, including brain-derived neurotrophic factor (BDNF) and dopamine, in modulating neural plasticity and motor control under these affective states. The review highlights the importance of developing therapeutic strategies that enhance motor performance by leveraging the interactions between key neurochemicals. Additionally, we investigate the complex interplay between emotional-cognitive states and sensorimotor behaviors, showing how stress and anxiety disrupt neural integration, leading to impairments in skilled movements and negatively impacting quality of life. Synthesizing evidence from human and rodent studies, we provide a detailed understanding of the relationships among stress, anxiety, and motor behavior. Our findings reveal neurophysiological pathways, behavioral outcomes, and potential therapeutic targets, emphasizing the intricate connections between neurobiological mechanisms, environmental factors, and motor performance.

Accelerated sarcopenia precedes learning and memory impairments in the P301S mouse model of tauopathies and Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) impairs cognitive functions and peripheral systems, including skeletal muscles. The PS19 mouse, expressing the human tau P301S mutation, shows cognitive and muscular pathologies, reflecting the central and peripheral atrophy seen in AD.

METHODS

We analysed skeletal muscle morphology and neuromuscular junction (NMJ) through immunohistochemistry and advanced image quantification. A factorial Analysis of Variance assessed muscle weight, NCAM expression, NMJ, myofibre type distribution, cross-sectional areas, expression of single or multiple myosin heavy-chain isoforms, and myofibre grouping in PS19 and wild type (WT) mice over their lifespan (1-12 months).

RESULTS

Significant weight differences in extensor digitorum longus (EDL) and soleus muscles between WT and PS19 mice were noted by 7-8 months. For EDL muscle in females, WT weighed 0.0113 ± 0.0005 compared with PS19's 0.0071 ± 0.0008 (P < 0.05), and in males, WT was 0.0137 ± 0.0001 versus PS19's 0.0069 ± 0.0006 (P < 0.005). Similarly, soleus muscle showed significant differences; females (WT: 0.0084 ± 0.0004; PS19: 0.0057 ± 0.0005, P < 0.005) and males (WT: 0.0088 ± 0.0003; PS19: 0.0047 ± 0.0004, P < 0.0001). Analysis of the NMJ in PS19 mice revealed a marked reduction in myofibre innervation at 5 months, with further decline by 10 months. NMJ pre-terminals in PS19 mice became shorter and simpler by 5 months, showing a steep decline by 10 months. Genotype and age strongly influenced muscle NCAM immunoreactivity, denoting denervation as early as 5-6 months in EDL muscle Type II fibres, with earlier effects in soleus muscle Type I and II fibres at 3-4 months. Muscle denervation and subsequent myofibre atrophy were linked to a reduction in Type IIB fibres in the EDL muscle and Type IIA fibres in the soleus muscle, accompanied by an increase in hybrid fibres. The EDL muscle showed Type IIB fibre atrophy with WT females at 1505 ± 110 μm2 versus PS19's 1208 ± 94 μm2, and WT males at 1731 ± 185 μm2 versus PS19's 1227 ± 116 μm2. Similarly, the soleus muscle demonstrated Type IIA fibre atrophy from 5 to 6 months, with WT females at 1194 ± 52 μm2 versus PS19's 858 ± 62 μm2, and WT males at 1257 ± 43 μm2 versus PS19's 1030 ± 55 μm2. Atrophy also affected Type IIX, I + IIA, and IIA + IIX fibres in both muscles. The timeline for both myofibre and overall muscle atrophy in PS19 mice was consistent, indicating a simultaneous decline.

CONCLUSIONS

Progressive and accelerated neurogenic sarcopenia may precede and potentially predict cognitive deficits observed in AD.

Association between sleep duration and possible sarcopenia in middle-aged and elderly Chinese individuals: evidence from the China health and retirement longitudinal study

BACKGROUND

Sarcopenia is a common cause of disability in the aging population, and managing sarcopenia is an important step in building intrinsic capacity and promoting healthy aging. A growing body of evidence suggests that sleep deprivation may be a mediator of the development of sarcopenia. The purpose of this study was to explore the longitudinal association between sleep duration and possible sarcopenia using data from a national sample.

METHODS

Two waves of data from the CHARLS database for 2011 and 2015 were used in this study. All possible sarcopenia participants met the Asia Working Group for Sarcopenia 2019 (AWGS 2019) diagnostic criteria. Sleep duration was assessed using a self-report questionnaire, and sleep duration was categorized as short (≤ 6 h), medium (6-8 h), or long (> 8 h) based on previous studies. Longitudinal associations between sleep duration and possible sarcopenia will be calculated by univariate and multifactorial logistic regression analyses and expressed as odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

A total of 5654 individuals participated in the follow-up study, with a prevalence of possible sarcopenia of 53.72% (578) in the short sleep duration group, 38.29% (412) in the medium sleep duration group, and 7.99% (86) in the long sleep duration group. According to the crude model of the second-wave follow-up study, short sleep durations were significantly more strongly associated with possible sarcopenia than were medium and long sleep durations (OR: 1.35, 95% CI: 1.17-1.55, P = 0.000). The association between short sleep duration and possible sarcopenia was maintained even after adjustment for covariates such as age, gender, residence, education level, BMI, smoking status, alcohol consumption and comorbidities (OR: 1.18, 95% CI: 1.02-1.36, P = 0.029). In the subgroup analysis, short sleep duration was associated with low grip strength (OR: 1.20, 95% CI: 1.02-1.41, P = 0.031).

CONCLUSIONS

Sleep deprivation may be closely associated with the development of possible sarcopenia in middle-aged and elderly people, which provides new insights and ideas for sarcopenia intervention, and further studies are needed to reveal the underlying mechanisms involved.

Differences in Daily Physical Activity by Alzheimer's Risk Markers Among Older Adults

BACKGROUND

Daily physical activity patterns differ by Alzheimer's disease (AD) status and might signal cognitive risk. It is critical to understand whether patterns are disrupted early in the AD pathological process. Yet, whether established AD risk markers (β-amyloid [Aβ] or apolipoprotein E-ε4 [APOE-ε4]) are associated with differences in objectively measured activity patterns among cognitively unimpaired older adults is unclear.

METHODS

Wrist accelerometry, brain Aβ (+/-), and APOE-ε4 genotype were collected in 106 (Aβ) and 472 (APOE-ε4) participants (mean age 76 [standard deviation{SD}: 8.5) or 75 [SD: 9.2] years, 60% or 58% women) in the Baltimore Longitudinal Study of Aging. Adjusted linear and function-on-scalar regression models examined whether Aβ or APOE-ε4 status was cross-sectionally associated with activity patterns (amount, variability, or fragmentation) overall and by time of day, respectively. Differences in activity patterns by combinations of Aβ and APOE-ε4 status were descriptively examined (n = 105).

RESULTS

There were no differences in any activity pattern by Aβ or APOE-ε4 status overall. Aβ+ was associated with lower total amount and lower within-day variability of physical activity overnight and early evening, and APOE-ε4 carriers had higher total amount of activity in the evening and lower within-day variability of activity in the morning. Diurnal curves of activity were blunted among those with Aβ+ regardless of APOE-ε4 status, but only when including older adults with mild cognitive impairment/dementia.

CONCLUSIONS

Aβ+ in cognitively unimpaired older adults might manifest as lower amount and variability of daily physical activity, particularly during overnight/evening hours. Future research is needed to examine changes in activity patterns in larger samples and by other AD biomarkers.

Discrete Relationships between Spatiotemporal Gait Characteristics and Domain-Specific Neuropsychological Performance in Midlife

Midlife risk factors such as type 2 diabetes mellitus (T2DM) confer a significantly increased risk of cognitive impairment in later life with executive function, memory, and attention domains often affected first. Spatiotemporal gait characteristics are emerging as important integrative biomarkers of neurocognitive function and of later dementia risk. We examined 24 spatiotemporal gait parameters across five domains of gait previously linked to cognitive function on usual-pace, maximal-pace, and cognitive dual-task gait conditions in 102 middle-aged adults with (57.5 ± 8.0 years; 40% female) and without (57.0 ± 8.3 years; 62.1% female) T2DM. Neurocognitive function was measured using a neuropsychological assessment battery. T2DM was associated with significant changes in gait phases and rhythm domains at usual pace, and greater gait variability observed during maximal pace and dual tasks. In the overall cohort, both the gait pace and rhythm domains were associated with memory and executive function during usual pace. At maximal pace, gait pace parameters were associated with reaction time and delayed memory. During the cognitive dual task, associations between gait variability and both delayed memory/executive function were observed. Associations persisted following covariate adjustment and did not differ by T2DM status. Principal components analysis identified a consistent association of slower gait pace (step/stride length) and increased gait variability during maximal-pace walking with poorer memory and executive function performance. These data support the use of spatiotemporal gait as an integrative biomarker of neurocognitive function in otherwise healthy middle-aged individuals and reveal discrete associations between both differing gait tasks and gait domains with domain-specific neuropsychological performance. Employing both maximal-pace and dual-task paradigms may be important in cognitively unimpaired populations with risk factors for later cognitive decline-with the aim of identifying individuals who may benefit from potential preventative interventions.

Linking Dementia Pathology and Alteration in Brain Activation to Complex Daily Functional Decline During the Preclinical Dementia Stages: Protocol for a Prospective Observational Cohort Study

BACKGROUND

Progressive difficulty in performing everyday functional activities is a key diagnostic feature of dementia syndromes. However, not much is known about the neural signature of functional decline, particularly during the very early stages of dementia. Early intervention before overt impairment is observed offers the best hope of reducing the burdens of Alzheimer disease (AD) and other dementias. However, to justify early intervention, those at risk need to be detected earlier and more accurately. The decline in complex daily function (CdF) such as managing medications has been reported to precede impairment in basic activities of daily living (eg, eating and dressing).

OBJECTIVE

Our goal is to establish the neural signature of decline in CdF during the preclinical dementia period.

METHODS

Gait is central to many CdF and community-based activities. Hence, to elucidate the neural signature of CdF, we validated a novel electroencephalographic approach to measuring gait-related brain activation while participants perform complex gait-based functional tasks. We hypothesize that dementia-related pathology during the preclinical period activates a unique gait-related electroencephalographic (grEEG) pattern that predicts a subsequent decline in CdF.

RESULTS

We provide preliminary findings showing that older adults reporting CdF limitations can be characterized by a unique gait-related neural signature: weaker sensorimotor and stronger motor control activation. This subsample also had smaller brain volume and white matter hyperintensities in regions affected early by dementia and engaged in less physical exercise. We propose a prospective observational cohort study in cognitively unimpaired older adults with and without subclinical AD (plasma amyloid-β) and vascular (white matter hyperintensities) pathologies. We aim to (1) establish the unique grEEG activation as the neural signature and predictor of decline in CdF during the preclinical dementia period; (2) determine associations between dementia-related pathologies and incidence of the neural signature of CdF; and (3) establish associations between a dementia risk factor, physical inactivity, and the neural signature of CdF.

CONCLUSIONS

By establishing the clinical relevance and biological basis of the neural signature of CdF decline, we aim to improve prediction during the preclinical stages of ADs and other dementias. Our approach has important research and translational implications because grEEG protocols are relatively inexpensive and portable, and predicting CdF decline may have real-world benefits.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/56726.

Sensory and motor deficits as contributors to early cognitive impairment

INTRODUCTION

Age-related sensory and motor impairment are associated with risk of dementia. No study has examined the joint associations of multiple sensory and motor measures on prevalence of early cognitive impairment (ECI).

METHODS

Six hundred fifty participants in the Baltimore Longitudinal Study of Aging completed sensory and motor function tests. The association between sensory and motor function and ECI was examined using structural equation modeling with three latent factors corresponding to multisensory, fine motor, and gross motor function.

RESULTS

The multisensory, fine, and gross motor factors were all correlated (r = 0.74 to 0.81). The odds of ECI were lower for each additional unit improvement in the multisensory (32%), fine motor (30%), and gross motor factors (12%).

DISCUSSION

The relationship between sensory and motor impairment and emerging cognitive impairment may guide future intervention studies aimed at preventing and/or treating ECI.

HIGHLIGHTS

Sensorimotor function and early cognitive impairment (ECI) prevalence were assessed via structural equation modeling. The degree of fine and gross motor function is associated with indicators of ECI. The degree of multisensory impairment is also associated with indicators of ECI.

Restoring Mitochondrial Function and Muscle Satellite Cell Signaling: Remedies against Age-Related Sarcopenia

Sarcopenia has a complex pathophysiology that encompasses metabolic dysregulation and muscle ultrastructural changes. Among the drivers of intracellular and ultrastructural changes of muscle fibers in sarcopenia, mitochondria and their quality control pathways play relevant roles. Mononucleated muscle stem cells/satellite cells (MSCs) have been attributed a critical role in muscle repair after an injury. The involvement of mitochondria in supporting MSC-directed muscle repair is unclear. There is evidence that a reduction in mitochondrial biogenesis blunts muscle repair, thus indicating that the delivery of functional mitochondria to injured muscles can be harnessed to limit muscle fibrosis and enhance restoration of muscle function. Injection of autologous respiration-competent mitochondria from uninjured sites to damaged tissue has been shown to reduce infarct size and enhance cell survival in preclinical models of ischemia-reperfusion. Furthermore, the incorporation of donor mitochondria into MSCs enhances lung and cardiac tissue repair. This strategy has also been tested for regeneration purposes in traumatic muscle injuries. Indeed, the systemic delivery of mitochondria promotes muscle regeneration and restores muscle mass and function while reducing fibrosis during recovery after an injury. In this review, we discuss the contribution of altered MSC function to sarcopenia and illustrate the prospect of harnessing mitochondrial delivery and restoration of MSCs as a therapeutic strategy against age-related sarcopenia.

Factors affecting cognitive frailty improvement and progression in Taiwanese older adults

BACKGROUND

Knowledge of predictors of cognitive frailty (CF) trajectories is required to develop preventive strategies to delay or reverse the progression from CF to dementia and other adverse outcomes. This 2-year prospective study aimed to investigate factors affecting the progression and improvement of CF in older Taiwanese adults.

METHODS

In total, 832 community-dwelling people aged ≥ 65 years were eligible. Fried's five frailty criteria were used to measure prefrailty and frailty, while cognitive performance was assessed by the Clinical Dementia Rating and Mini-Mental State Examination. Each component of reversible CF and potentially reversible CF was assigned a score, with a total score ranging 0 to 5 points. Two annual follow-up CF assessments were conducted. The group-based trajectory model was applied to identify latent CF trajectory groups, and a multinomial logistic regression was used to examine relationships of explanatory variables with CF trajectories.

RESULTS

According to data on 482 subjects who completed the two annual follow-ups, three CF trajectories of robust, improvement, and progression were identified. After adjusting for the baseline CF state, CF progression was significantly associated with an older age (odds ratio [OR] = 1.08; 95% confidence interval [CI], 1.02 ~ 1.14), a lower Tinetti balance score (OR = 0.72; 95% CI, 0.54 ~ 0.96), a slower gait (OR = 0.98; 95% CI, 0.97 ~ 0.99), and four or more comorbidities (OR = 2.65; 95% CI, 1.19 ~ 5.90), while CF improvement was not significantly associated with any variable except the baseline CF state. In contrast, without adjusting for the baseline CF state, CF progression was significantly associated with an older age, female sex, balance scores, gait velocity, regular exercise, the number of comorbidities, and depression, while CF improvement was significantly associated with female sex, balance scores, and the number of comorbidities.

CONCLUSIONS

The baseline CF state, an older age, poorer balance, slower gait, and a high number of comorbidities may contribute to CF progression, while the baseline CF state may account for associations of engaging in regular exercise and depression with CF development.

Gait Parameters can Reflect Cognitive Performance in Older Adults with Cerebral Small Vessel Disease: A Cross-sectional Research

BACKGROUND

Cerebral small vessel disease (CSVD) is a common chronic progressive disease. It remains unclear whether high gait variability is a marker of cognitive cortical dysfunction.

METHODS

This study included 285 subjects (aged from 60 to 85 years, 60.3% female) including 37 controls, 179 presented as Fazekas II, and 69 presented as Fazekas III. The severity of white matter hyperintensities was assessed by the Fazekas Rating Scale. Gait parameters were assessed using a vision-based artificial intelligent gait analyzer. Cognitive function was tested by MMSE, MoCA, DST, and VFT.

RESULTS

Three gait parameters including gait speed, gait length, and swing time were associated with cognitive performance in patients with CSVD. Gait speed was associated with cognitive performance, including MMSE (β 0.200; 95%CI 1.706-6.018; p <.001), MoCA (β 0.183; 95%CI 2.047-7.046; p <.001), DST (order) (β 0.204; 95%CI 0.563-2.093; p =.001) and VFT (β 0.162; 95%CI 0.753-4.865; p =.008). Gait length was associated with cognitive performance, including MMSE (β 0.193; 95%CI 3.475-12.845; p =.001), MoCA (β 0.213; 95%CI 6.098-16.942; p <.001), DST (order) (β 0.224; 95%CI 1.056-4.839; P <.001) and VFT (β 0.149; 95%CI 1.088- 10.114; p =.015). Swing time was associated with cognitive performance, including MMSE (β - 0.242; 95%CI -2.639 to -0.974; p<.001), MoCA (β -0.211; 95%CI -2.989 to -1.034; p <.001) and DST (reverse order) (β -0.140; 95%CI -0.568 to -0.049; p =.020).

CONCLUSION

This study revealed that the relationship between gait parameters and cognitive performance in patients with CSVD and the deteriorated gait parameters can reflect cognitive impairment and even dementia in older people with CSVD.

Concurrent Validity of Dual-Task Walking Speed With CERAD-NP Assessment Battery in Community-Dwelling Older Adults

Objective

To explore the concurrent validity of the dual-task walking speed assessments in older adults using the Consortium to Establish a Registry for Alzheimer's Disease Neuro-Psychological (CERAD-NP) Assessment Battery.

Design

Cross-sectional design.

Setting

Welfare care centers, Senior complex centers, and Dementia prevention care centers.

Participants

A total of 163 community-dwelling older adults (N=163) were recruited using consecutive sampling. Participants were composed of 65 older adults with cognitive decline and 98 without cognitive decline.

Interventions

Not applicable.

Main Outcome Measures

This study assessed the concurrent validity between dual-task walking speed assessments and the Total II score of CERAD-NP using Spearman's rank order correlations. The effect of the dual-task walking speed assessments on the Total II score was further investigated through multiple linear regression analysis.

Results

There was a moderate and statically significant association between the Total II score and all 8 dual-task walking speed assessments (P<.05). The Total II score was strongly associated with the dual tasks of walking on a straight path while counting backward and crossing over an obstacle (r=0.698, r=0.697, respectively; P<.05). According to multiple linear regression, only the dual task of walking while counting backward was significantly associated with the Total II score (P<.05).

Conclusion

The dual-task walking speed assessments, which involved walking and performing a secondary task such as counting backward or crossing an obstacle on a straight path, were highly indicative of cognitive decline. The combination of results from both tasks may provide a more comprehensive evaluation of cognitive decline compared with relying solely on a single-task assessment.

Correlates of Gait Speed Among Older Adults From 6 Countries: Findings From the COSMIC Collaboration

BACKGROUND

Few studies have compared gait speed and its correlates among different ethnogeographic regions. The goals of this study were to describe usual and rapid gait speed, and identify their correlates across Australian, Asian, and African countries.

METHODS

We used data from 6 population-based cohorts of adults aged 65+ from 6 countries and 3 continents (N = 6 472), with samples ranging from 231 to 1 913. All cohorts are members of the Cohort Studies of Memory in an International Consortium collaboration. We investigated whether clinical (body mass index [BMI], hypertension, stroke, apolipoprotein status), psychological (cognition, mood, general health), and behavioral factors (smoking, drinking, physical activity) correlated with usual (N = 4 cohorts) and rapid gait speed (N = 3 cohorts) similarly across cohorts. Regression models were controlled for age, sex, and education, and were sex-stratified.

RESULTS

Age- and sex-standardized usual gait speed means ranged from 0.61 to 1.06 m/s and rapid gait speed means ranged from 1.16 to 1.64 m/s. Lower BMI and better cognitive function consistently correlated with faster gait speed in all cohorts. Less consistently, not having hypertension and greater physical activity engagement were associated with faster gait speed. Associations with mood, smoking, and drinking were largely nonsignificant. These patterns were not attenuated by demographics. There was limited evidence that the associations differed by sex, except physical activity, where the greater intensity was associated with usual gait among men but not women.

CONCLUSIONS

This study is among the first to describe the usual and rapid gait speeds across older adults in Africa, Asia, and Australia.

Associations Between Circulating Levels of Myostatin and Plasma β-Amyloid 42/40 in a Biracial Cohort of Older Adults

BACKGROUND

Myostatin, a cytokine produced by skeletal muscle, may influence Alzheimer's disease (AD) pathogenesis, but sparse evidence exists in humans. We assessed the association between circulating levels of myostatin at Year 1 and plasma levels of β-amyloid 42/40 at Year 2, a marker of AD pathology, in a biracial cohort of older adults.

METHODS

We studied 403 community-dwelling older adults enrolled in the Health, Aging and Body Composition Study from Memphis, Tennessee, and Pittsburgh, PA. Mean age was 73.8 ± 3 years; 54% were female; and 52% were Black. Serum myostatin levels were measured at Year 1, plasma β-amyloid 42/40 levels in Year 2 (higher ratio indicating lower amyloid load). Multivariable linear regression analyses tested the association of serum myostatin with plasma levels of β-amyloid 42/40 adjusted for computed-tomography-derived thigh muscle cross-sectional area, demographics, APOe4 allele, and risk factors for dementia. We tested for 2-way.interactions between myostatin and race or sex; results were stratified by race and sex.

RESULTS

In multivariable models, myostatin was positively associated with plasma levels of β-amyloid 42/40 (standardized regression coefficient: 0.145, p = .004). Results were significant for white men and women (0.279, p = .009, and 0.221, p = .035, respectively) but not for Black men or women; interactions by race and gender were not statistically significant.

CONCLUSIONS

Higher serum myostatin was associated with lower amyloid burden, independently of APOe4 alleles, muscle area and other established risk factors for dementia. The role of myostatin in AD pathogenesis and the influence of race should be further investigated.

Fall risk is related to cognitive functioning in ambulatory multiple sclerosis patients

BACKGROUND AND AIMS

Patients with multiple sclerosis (PwMS) may suffer severely from falling and gait disturbance. Cognitive dysfunction, a common condition in MS patients, may also increase falling rates, regardless of physical disability. We planned this study to determine the fall rate and risk factors in MS patients, follow patients for falls, and reveal the relationship between falls and cognitive dysfunction.

METHODS

The study was conducted on 124 patients who have RRMS diagnoses. Patients' gait speed, simultaneous gait speed during other tasks, functions of the upper extremity, balance rating, and fear of falling were evaluated with dual-task Timed-Up-and-Go-3 versions (TUG, TUG-C, TUG-M), Timed 25 Foot Walk (T25WFT), Nine Hole Peg Test (9HPT), Berg Balance Scale (BBS) and Falls Efficacy Scale-International (FES-I) tests. Cognitive functions, fatigue levels, and quality of life were measured with the Symbol Digit Modalities Test (SDMT), Fatigue Severity Scale (FSS), and Multiple Sclerosis Quality of Life (MSQoL) test. Two groups were formed as "fallers" and "non-faller patients". We monitored the patients in six months period.

RESULTS

Forty-six patients fell at least once in the last one year before the study began. Fallers were older, less educated, had lower SDMT scores and higher disability scores. Non-faller patients scored lower in FES-I, TUG, and FSS tests. SDMT scores showed statistically significant, linear, positive, and moderate correlation with BBS and 9HPT scores (r = 0.307, p = 0.038, and r = 0.320, p = 0.030, respectively).

CONCLUSION

We determined that advanced age, lower education level, and cognitive dysfunction adversely affect gait speed and balance. Among the fallers, those with lower SDMT and MoCA scores had higher falling rates. We determined that EDSS and BBS scores are predictive factors for falls in patients with MS. In conclusion, patients with cognitive impairment should be closely monitored for the risk of falling. Consideration of falls during follow-up examinations might be predictive of cognitive deterioration in patients with MS.

Investigating the efficacy of a tactile feedback system to increase the gait speed of older adults

The objective of this study was to determine (1) if a novel haptic feedback system could increase the walking speed of older adults while it is being employed during overground walking and (2) whether the frequency at which this feedback was presented would have a differential impact on the ability of users to change walking speed while it was present. Given that peak thigh extension has been found to be a biomechanical surrogate for stride length, and consequently gait speed, vibrotactile haptic feedback was provided to the participants' thighs as a cue to increase peak thigh extension while the effect on gait speed was monitored. Ten healthy community-dwelling older adults (68.4 ± 4.1 years) participated. Participants' peak thigh extension, cadence, normalized stride length and velocity, along with their coefficients of variation (COV) were compared across baseline normal and fast walking (with no feedback) and three different frequency of feedback conditions. The findings indicated that, compared to self-selected normal and fast walking speeds, peak thigh extension was significantly increased when feedback was present and after it was withdrawn in a post-test. An increase in thigh extension led to an increase in stride length and, consequently, an increase in stride velocity compared to normal speed. There were no significant differences in the gait parameters as a function of feedback frequency during its application. In conclusion, while present, the haptic feedback system increased thigh extension and walking speed in older adults regardless of the feedback frequency and when the feedback was withdrawn, participants could maintain an increase in those parameters.

Associations of physical function and body mass index with functional brain networks in community-dwelling older adults

Deficits in physical function that occur with aging contribute to declines in quality of life and increased mortality. There has been a growing interest in examining associations between physical function and neurobiology. Whereas high levels of white matter disease have been found in individuals with mobility impairments in structural brain studies, much less is known about the relationship between physical function and functional brain networks. Even less is known about the association between modifiable risk factors such as body mass index (BMI) and functional brain networks. The current study examined baseline functional brain networks in 192 individuals from the Brain Networks and mobility (B-NET) study, an ongoing longitudinal, observational study in community-dwelling adults aged 70 and older. Physical function and BMI were found to be associated with sensorimotor and dorsal attention network connectivity. There was a synergistic interaction such that high physical function and low BMI were associated with the highest network integrity. White matter disease did not modify these relationships. Future work is needed to understand the causal direction of these relationships.

Influence of transcutaneous electrical nerve stimulation on walking kinematics and standing balance of older adults who differ in walking speed

The purpose was to determine the impact of transcutaneous electrical nerve stimulation (TENS) on measures of walking kinematics and standing balance of healthy older adults who were stratified into two groups based on differences in the distance walked during the 6-min test of walking endurance. Regression models were developed to explain the variance in the 6-min distance and to assess the predictive power of balance metrics to categorize the 26 older adults (72 ± 5.4 yrs) as either slow or fast walkers. Walking kinematics were measured during 6- and 2-min walk tests that were performed with and without the concurrent application of TENS to the hip flexor and ankle dorsiflexor muscles. Participants walked briskly during the 6-min test and at a preferred pace during the 2-min test. The supplementary sensory stimulation provided by TENS did not alter the power of the models to explain the variance in the Baseline 6-min distance: Baseline, R² = 0.85; TENS, R² = 0.83. In contrast, TENS improved the explanatory power of the data obtained during the 2-min walk to account for the variance in the Baseline 6-min distance: no TENS, R² = 0.40; TENS, R² = 0.64. Logistic regression models based on force-plate and kinematic data obtained during the balance tasks were able to discriminate between the two groups with excellent certainty. The impact of TENS was greatest when older adults walked at a preferred speed but not when they walked at a brisk pace or performed tests of standing balance.

Effects of diabetes mellitus on step length and minimum toe clearance adaptation

BACKGROUND

Adaptive gait involves the ability to adjust the leading foot in response to the requirement of dynamic environments during walking. Accurate adjustments of the minimum toe clearance (MTC) height and step length can prevent older people from falling when walking and responding to hazards. Although older people with diabetes fall more frequently than healthy older adults, no previous studies have quantified their adaptive gait abilities. This study aimed to investigate the effects of diabetes mellitus on step length and MTC height adjustments using a non-immersive virtual-reality system.

METHODS

Sixteen young adults (26 ± 5 years, 7 females), 16 healthy older adults (68 ± 5 years, 6 females), and 16 older adults with diabetes (70 ± 5 years, 6 females) completed adaptability tests while walking on a treadmill. A computer system visualised a continuous real-time signal of absolute step length and MTC on a monitor. Each person responded to four discrete participant-specific step length and MTC visual targets that were presented on the same signal. Tasks were to match the peaks of interest on each signal to presented targets. Targets were 10% longer or shorter than the mean baseline step length, and 2.5 cm, and 3.5 cm higher than the mean baseline MTC. When a target was displayed, it remained unchanged for 10 consecutive foot displacement adaptation attempts. Then, the target was removed and a new target or the same target was present after 10 consecutive steps and remained for 10 steps. Each target was randomly presented three times (3 × 10). Step length and MTC height adjustments in response to targets were measured and compared among groups.

RESULTS

Mean preferred walking speeds were not different among groups significantly when no targets were presented on the monitor in baseline walking. However, when participants walked on a treadmill while attempting to match step lengths or MTC heights to displayed targets on the monitor, the group with diabetes had reduced step length and MTC adjustments compared with other groups significantly. They showed greater errors (differences between their step lengths/MTC heights and presented targets) on the monitor.

CONCLUSIONS

This study quantified reduced abilities for older individuals with diabetes to adjust both step length and MTC in response to stimuli compared to healthy older counterparts. Reduced step length and MTC height adjustments can increase falls in at risk populations. The presented virtual-reality system has merits for assessing and training step and MTC adaptation.

Adaptation to repeated standing-slips in professional ballet dancers

Ballet training is being increasingly used to improve physical functions in older adults. Our previous work showed that ballet dancers react to a novel standing-slip more effectively than their non-dancer counterparts through better control of the recovery step and trunk movement. The purpose of this study was to test if and to what extent ballet dancers adapt differently to repeated standing-slips relative to non-dancers. Protected by a harness, twenty young adults (10 professional ballet dancers and 10 age/sex-matched non-dancers) experienced five repeated and standardized standing-slips on a treadmill. Changes from the first slip (S1) to the fifth slip (S5) in dynamic gait stability (primary outcome) and other variables, including the center of mass position and velocity, step latency, slip distance, ankle angle, and trunk angle (secondary outcomes) were compared between groups. Results revealed that both groups adopted similar proactive controls to improve dynamic gait stability by using the ankle and hip strategies. However, dancers showed a better reactive improvement in stability after the repeated slips than non-dancers. From S1 to S5, dancers reactively improved their dynamic gait stability more than non-dancers at the recovery step liftoff (p = 0.003). Dancers decreased their recovery step latency (p = 0.004) and shortened the slip distance (p = 0.004) significantly more than non-dancers from S1 to S5. These findings suggest that ballet dancers could facilitate the adaptation to repeated slips, which may be attributed to their ballet practice experience. This finding augments our understanding of the underlying mechanisms of ballet practice reducing falls.

Towards a core-set of mobility measures in ageing research: The need to define mobility and its constructs

BACKGROUND

Mobility is a key determinant and outcome of healthy ageing but its definition, conceptual framework and underlying constructs within the physical domain may need clarification for data comparison and sharing in ageing research. This study aimed to (1) review definitions and conceptual frameworks of mobility, (2) explore agreement on the definition of mobility, conceptual frameworks, constructs and measures of mobility, and (3) define, classify and identify constructs.

METHODS

A three-step approach was adopted: a literature review and two rounds of expert questionnaires (n = 64, n = 31, respectively). Agreement on statements was assessed using a five-point Likert scale; the answer options 'strongly agree' or 'agree' were combined. The percentage of respondents was subsequently used to classify agreements for each statement as: strong (≥ 80%), moderate (≥ 70% and < 80%) and low (< 70%).

RESULTS

A variety of definitions of mobility, conceptual frameworks and constructs were found in the literature and among respondents. Strong agreement was found on defining mobility as the ability to move, including the use of assistive devices. Multiple constructs and measures were identified, but low agreements and variability were found on definitions, classifications and identification of constructs. Strong agreements were found on defining physical capacity (what a person is maximally capable of, 'can do') and performance (what a person actually does in their daily life, 'do') as key constructs of mobility.

CONCLUSION

Agreements on definitions of mobility, physical capacity and performance were found, but constructs of mobility need to be further identified, defined and classified appropriately. Clear terminology and definitions are essential to facilitate communication and interpretation in operationalising the physical domain of mobility as a prerequisite for standardisation of mobility measures.

Association of gait speed with regional brain volumes and risk of dementia in older Japanese: The Hisayama study

BACKGROUND

To investigate the association of gait speed with regional brain volumes and the risk of incident dementia.

METHODS

A total of 1112 dementia-free Japanese residents aged ≥65 years who underwent brain magnetic resonance imaging were followed for 5.0 years (median). The participants were classified into the age- and sex-specific quartile levels of maximum gait speed. Regional gray matter volumes (GMV) and white matter hyperintensities volumes (WMHV) were measured by applying voxel-based morphometry methods. The cross-sectional association of maximum gait speed with regional GMV was examined using an analysis of covariance. We also estimated the association between maximum gait speed level and the risk of developing dementia using a Cox proportional hazards model. Mediation analyses were conducted to determine the contribution of regional brain volumes to the association between maximum gait speed and dementia.

RESULTS

Lower maximum gait speed was significantly associated with lower GMV of the total brain, frontal lobe, temporal lobe, cingulate gyrus, insula, hippocampus, amygdala, basal ganglia, thalamus, and cerebellum, and increased WMHV at baseline. During the follow-up, 108 participants developed dementia. The incidence rate of all dementias increased significantly with decreasing maximum gait speed after adjusting for potential confounders (P for trend = 0.03). The mediating effects of the GMV of the hippocampus, GMV of the insula, and WMHV were significant.

CONCLUSIONS

Lower maximum gait speed was significantly associated with an increased risk of dementia. Reduced GMV of the hippocampus or insula, and an increase in WMHV was likely to be involved in this association.

Neurodegenerative and Cerebrovascular Brain Pathologies Are Differentially Associated With Declining Grip Strength and Gait In Older Adults

BACKGROUND

Understanding the pathological bases underlying the heterogeneity of motor decline in old age may lead to targeted treatments. We examined whether different brain pathologies are related to declining grip strength and gait function.

METHODS

We examined postmortem brains of older adults who underwent annual motor testing. Postmortem exam measured 6 neurodegenerative and 5 cerebrovascular disease (CVD) pathologies. Grip strength was measured twice bilaterally using a hand-held dynamometer, and gait function was a composite measure based on time and steps taken to walk 8 ft and perform a 360° turn twice.

RESULTS

In separate linear mixed-effects models including all autopsied adults (N = 1 217), neurodegenerative pathologies including tau tangles, TDP-43, and nigral neuronal loss were associated with declining grip strength, but not CVD pathologies. In contrast, although both CVD and neurodegenerative pathologies were associated with declining gait function, CVD pathologies accounted for 75% of the variance of declining rate of gait function explained by brain pathologies and neurodegenerative pathologies accounted for 25%. These findings were unchanged in adults (n = 970) without a history of stroke. Restricting analyses to only adults without dementia (n = 661), CVD pathologies continued to account for the majority of the variance of declining gait. However, we failed to detect in this subgroup the variance of declining grip strength explained by neurodegenerative or CVD pathologies.

CONCLUSION

Different pathologies accumulating in aging brains may contribute to the phenotypic heterogeneity of motor decline. Larger studies are needed in older adults without dementia to assess differences in the motor consequences of varied brain pathologies.

Brain predicted age difference mediates pain impact on physical performance in community dwelling middle to older aged adults

The purpose of the study was to examine associations between physical performance and brain aging in individuals with knee pain and whether the association between pain and physical performance is mediated by brain aging. Participants (n=202) with low impact knee pain (n=111), high impact knee pain (n=60) and pain-free controls (n=31) completed self-reported pain, magnetic resonance imaging (MRI), and a Short Physical Performance Battery (SPPB) that included balance, walking, and sit to stand tasks. Brain predicted age difference, calculated using machine learning from MRI images, significantly mediated the relationships between walking and knee pain impact (CI: -0.124; -0.013), walking and pain-severity (CI: -0.008; -0.001), total SPPB score and knee pain impact (CI: -0.232; -0.025), and total SPPB scores and pain-severity (CI: -0.019; -0.001). Brain-aging begins to explain the association between pain and physical performance, especially walking. This study supports the idea that a brain aging prediction can be calculated from shorter duration MRI sequences and possibly implemented in a clinical setting to be used to identify individuals with pain who are at risk for accelerated brain atrophy and increased likelihood of disability.

The development of split-treadmill with a fall prevention training function

BACKGROUND

The weakening of the ability of the elderly to perform gait is becoming a major cause of the increase in the frequency of falls.

OBJECTIVE

In this study, we designed and manufactured a treadmill capable of restraining walking by providing a sudden repulsive force on the left and right legs of a pedestrian when walking for the fall prevention training of the elderly. Through this, it is possible for the elderly person to strengthen the lower extremity muscles to prevent and prepare for falling through the fall prevention training similar to the fall environment that may occur in daily life.

METHOD

The development system includes a motor for generating a driving force in the form of a left and a right driving system and a belt separated from each other, an electromagnetic clutch for rapidly stopping the running belt of the motor transmitted to the running belt to stop the running belt, and a controller for controlling the driver.

RESULTS

In order to evaluate the development system, the motor driving ability test and the power transmission, connection and shut-off performance of the electromagnetic clutch were carried out. The subject's muscle activity of the lower extremity muscles was evaluated when the running belt stopped at the beginning of the right folding.

CONCLUSION

It is expected that the developed dual function system would be helpful for the fall prevention exercise as well as the rehabilitation exercise for patients who have recovered from surgery or hemiplegic patients.

Neural signature of mobility-related everyday function in older adults at-risk of cognitive impairment

Assessment of everyday activities is central to the diagnosis of dementia. Yet, little is known about brain processes associated with everyday functional limitations, particularly during early stages of cognitive decline. Twenty-six older adults (mean = 74.9 y) were stratified by risk using the Montreal Cognitive Assessment battery (MoCA, range: 0- 30) to classify individuals as higher (22-26) and lower risk (27+) of cognitive impairment. We investigated everyday function using a gait task designed to destabilize posture and applied Mobile Brain/Body Imaging. We predicted that participants would increase step width to gain stability, yet the underlying neural signatures would be different for lower versus higher risk individuals. Step width and fronto-parietal activation increased during visually perturbed input. Frontomedial theta increased in higher risk individuals during perturbed and unperturbed inputs. Left sensorimotor beta decreased in lower risk individuals during visually perturbed input. Modulations in theta and beta power were associated with MoCA scores. Our findings suggest that older adults at-risk of cognitive impairment can be characterized by a unique neural signature of everyday function.

Validation of an Ear-Worn Wearable Gait Analysis Device

Wearable devices capable of measuring gait parameters may provide a means to more economical gait analysis compared to conventional equipment comprising of a motion capture system and a forced treadmill. Beflex Coach (Beflex, Republic of Korea) is one such device but worn on the ear as Bluetooth earphones, unlike other wearables worn on the wrist, feet, or torso. In this study, the validity of the device was examined against a motion capture system and a forced treadmill for walking and running parameters. Five walking parameters (cadence, single support time, double support time, vertical oscillation (VO), and instantaneous vertical loading rate (IVLR)) and six running parameters (cadence, stance time, flight time, peak force, VO, and IVLR) were studied. Twenty young adults participated in walking or running on a forced treadmill at different speeds (walking: 0.8, 1.25, and 1.7 m/s for walking; running: 2, 2.5, and 3 m/s) while the two systems operated simultaneously. As a result, all parameters showed excellent associations (ICC > 0.75) and good agreements in Bland-Altman plots. The results of the study support the potential use of the ear-worn device as an inexpensive gait analysis equipment.

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.

Life-space Mobility in Older Men: The Role of Perceived Physical and Mental Fatigability

BACKGROUND

Physical performance and fatigue can limit mobility within the larger environment (life-space mobility). It is unknown whether perceived fatigability, self-reported fatigue anchored to activity intensity and duration, is independently associated with life-space.

METHODS

We assessed this cross-sectionally in Visit 4 (2014-2016) of the Osteoporotic Fractures in Men Study (MrOS; N = 1 672, Age: Mean = 84.2 ± 4.0 years). The Pittsburgh Fatigability Scale (PFS, range: 0-50; higher = greater fatigability) measured physical (Mean = 16.1 ± 9.4) and mental fatigability (Mean = 7.5 ± 7.9). Life Space Assessment scores incorporated level, frequency, and assistance used for life-space mobility (range: 0-120, higher = greater life-space mobility; life-space constriction: inability to leave neighborhood without assistance). Separate multiple linear and logistic regressions for physical and mental fatigability were sequentially adjusted for demographic, health/lifestyle, and performance measures.

RESULTS

The mean life-space mobility score was 84.6 ± 21.8, and 18% (n = 296) of men had life-space constriction. Higher physical and mental fatigability were both associated with lower life-space mobility in models adjusted for health and lifestyle factors (Physical PFS: B = -2.37, 95% confidence interval [CI]: [-3.39, -1.35]; Mental PFS: B = -1.79, 95% CI: [-2.73, -0.84]). Men with higher fatigability also had increased risk of life-space constriction (Physical PFS: OR = 1.59, 95% CI: [1.32, 1.92]; Mental PFS: OR = 1.25, 95% CI: [1.08, 1.46]). Associations were larger in magnitude for physical versus mental fatigability. Adjusting for physical performance measures more strongly attenuated associations for physical compared to mental fatigability.

CONCLUSIONS

Fatigability is linked with real-world mobility in older men, independent of their physical health. This association may be driven by separate physical and cognitive mechanisms worth examining further in longitudinal studies.

Energetic Cost of Walking and Brain Atrophy in Mid-to-Late Life

BACKGROUND

Higher energetic costs for mobility are associated with declining gait speed, and slow gait is linked to cognitive decline and Alzheimer's disease. However, the physiological underpinnings of gait and brain health have not been well explored. We examined the associations of the energetic cost of walking with brain volume in cognitively unimpaired adults from the Baltimore Longitudinal Study of Aging.

METHODS

We used brain magnetic resonance imaging (MRI) data from 850 participants (mean baseline age 66.3 ± 14.5 years), of whom 451 had longitudinal MRI data (2.8 ± 1.0 MRI scans over 4.0 ± 2.0 years). The energetic cost of walking was assessed as the average energy expended (V̇O2) during 2.5 minutes of customary-paced overground walking. Multivariable linear mixed-effects models examined the associations between baseline energetic cost of walking and regional brain volumes adjusting for covariates.

RESULTS

At baseline, higher energetic cost of walking was cross-sectionally associated with lower gray and white matter volumes within the frontal, parietal, and temporal lobes, as well as hippocampal, total brain, and larger ventricular volumes (all false-discovery rate [FDR] p < .05). A baseline energetic cost of walking × time interaction demonstrated that participants with higher energetic cost of walking had faster annual decline in hippocampal volume (FDR p = .02) and accelerated annual increase in ventricular volumes (FDR p = .02).

CONCLUSIONS

The energetic cost of walking is associated with gray and white matter volumes and subsequent hippocampal atrophy and ventricular enlargement. Collectively, these data suggest the energetic cost of walking may be an early marker of neurodegeneration that contributes to the gait brain connection.

Effects of aging on cognitive and brain inter-network integration patterns underlying usual and dual-task gait performance

Introduction

Aging affects the interplay between cognition and gait performance. Neuroimaging studies reported associations between gait performance and structural measures; however, functional connectivity (FC) analysis of imaging data can help to identify dynamic neural mechanisms underlying optimal performance. Here, we investigated the effects on divergent cognitive and inter-network FC patterns underlying gait performance during usual (UW) and dual-task (DT) walking.

Methods

A total of 115 community-dwelling, healthy participants between 20 and 80 years were enrolled. All participants underwent comprehensive cognitive and gait assessments in two conditions and resting state functional MRI (fMRI) scans. Inter-network FC from motor-related to 6 primary cognitive networks were estimated. Step-wise regression models tested the relationships between gait parameters, inter-network FC, neuropsychological scores, and demographic variables. A threshold of p < 0.05 was adopted for all statistical analyses.

Results

UW was largely associated with FC levels between motor and sustained attention networks. DT performance was associated with inter-network FC between motor and divided attention, and processing speed in the overall group. In young adults, UW was associated with inter-network FC between motor and sustained attention networks. On the other hand, DT performance was associated with cognitive performance, as well as inter-network connectivity between motor and divided attention networks (VAN and SAL). In contrast, the older age group (> 65 years) showed increased integration between motor, dorsal, and ventral attention, as well as default-mode networks, which was negatively associated with UW gait performance. Inverse associations between motor and sustained attention inter-network connectivity and DT performance were observed.

Conclusion

While UW relies on inter-network FC between motor and sustained attention networks, DT performance relies on additional cognitive capacities, increased motor, and executive control network integration. FC analyses demonstrate that the decline in cognitive performance with aging leads to the reliance on additional neural resources to maintain routine walking tasks.

Correlation between parameters related to sarcopenia and gray matter volume in patients with mild to moderate Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disease characterized by brain atrophy and closely correlated with sarcopenia. Mounting studies indicate that parameters related to sarcopenia are associated with AD, but some results show inconsistent. Furthermore, the association between the parameters related to sarcopenia and gray matter volume (GMV) has rarely been explored.

AIM

To investigate the correlation between parameters related to sarcopenia and cerebral GMV in AD.

METHODS

Demographics, neuropsychological tests, parameters related to sarcopenia, and magnetic resonance imaging (MRI) scans were collected from 42 patients with AD and 40 normal controls (NC). Parameters related to sarcopenia include appendicular skeletal muscle mass index (ASMI), grip strength, 5-times sit-to-stand (5-STS) time and 6-m gait speed. The GMV of each cerebral region of interest (ROI) and the intracranial volume were calculated by computing the numbers of the voxels in the specific region based on MRI data. Partial correlation and multivariate stepwise linear regression analysis explored the correlation between different inter-group GMV ratios in ROIs and parameters related to sarcopenia, adjusting for covariates.

RESULTS

The 82 participants included 40 NC aged 70.13 ± 5.94 years, 24 mild AD patients aged 73.54 ± 8.27 years and 18 moderate AD patients aged 71.67 ± 9.39 years. Multivariate stepwise linear regression showed that 5-STS time and gait speed were correlated with bilateral hippocampus volume ratios in total AD. Grip strength was associated with the GMV ratio of the left middle frontal gyrus in mild AD and the GMV ratios of the right superior temporal gyrus and right hippocampus in moderate AD. However, ASMI did not have a relationship to any cerebral GMV ratio.

CONCLUSIONS

Among parameters related to sarcopenia, 5-STS time and gait speed were associated with bilateral hippocampus volume ratios at different clinical stages of patients with AD. Five-STS time provide an objective basis for early screening and can help diagnose patients with AD.

Epigenetic aging, knee pain and physical performance in community-dwelling middle-to-older age adults

Knee pain is a leading cause of disability in the aging population and may indirectly accelerate biological aging processes. Chronological aging increases the risk of developing of knee pain and knee pain reduces physical function; however, limited data exist on how epigenetic aging, a known hallmark of biological aging shown to predict health span and mortality, may influence this relationship. The purpose of this study was to examine whether decreased physical performance associated with knee pain is mediated by markers of epigenetic aging. Participants (57.91 ± 8.04 years) with low impact knee pain (n = 95), high impact knee pain (n = 53) and pain-free controls (n = 26) completed self-reported pain, a blood draw and a short physical performance battery (SPPB) that included balance, walking, and sit to stand tasks. We employed an epigenetic clock previously associated with knee pain and shown to predict overall mortality risk (DNAmGrimAge). Bootstrapped-mediation analyses were used to determine associations of DNAmGrimAge and SPPB between pain groups. Those with high impact and low impact pain had a biologically older epigenetic age (5.14y ± 5.66 and 1.32y ± 5.41, respectively). However, while there were direct effects of pain on overall physical performance, these were not explained by epigenetic aging. Epigenetic aging only mediated the effect of pain on balance performance. Future work is needed to examine pain's impact on biological aging processes including epigenetic aging and its ultimate effect on physical function measures known to predict health span and mortality.

Brain Changes and Fast Cognitive and Motor Decline in Older Adults

BACKGROUND

To identify brain magnetic resonance imaging (MRI) signatures characterizing people with different patterns of decline in cognition and motor function.

METHODS

In the Swedish National Study on Aging and Care in Kungsholmen, Stockholm, 385 participants had available repeated brain MRI examinations, where markers of brain volumes and white matter integrity were assessed. The speed of cognitive and motor decline was estimated as the rate of a Mini-Mental State Examination and gait speed decline over 12 years (linear mixed models), and further dichotomized into the upper (25% fastest rate of decline) versus the lower quartiles. Participants were grouped in slow/no decliners (reference), isolated motor decliners, isolated cognitive decliners, and cognitive and motor decliners. We estimated the associations between changes in brain markers (linear mixed models) and baseline diffusion tensor imaging measures (linear regression model) and the 4 decline patterns.

RESULTS

Individuals with concurrent cognitive and motor decline (n = 51) experienced the greatest loss in the total brain (β: -12.3; 95% confidence interval [CI]: -18.2; -6.38) and hippocampal (β: -0.25; 95% CI: -0.34; -0.16) volumes, the steepest accumulation of white matter hyperintensities (β: 1.61; 95% CI: 0.54; 2.68), and the greatest ventricular enlargement (β: 2.07; 95% CI: 0.67; 3.47). Compared to the reference, those only experiencing cognitive decline presented with steeper hippocampal volume loss, whereas those exhibiting only motor decline displayed a greater white matter hyperintensities burden. Lower microstructural white matter integrity was associated with concurrent cognitive and motor decline.

CONCLUSION

Concurrent cognitive and motor decline is accompanied by rapidly evolving and complex brain pathology involving both gray and white matter. Isolated cognitive and motor declines seem to exhibit brain damage with different qualitative features.

Association of the prefrailty with global brain atrophy and white matter lesions among cognitively unimpaired older adults: the Nakajima study

Physical frailty has been associated with adverse outcomes such as dementia. However, the underlying structural brain abnormalities of physical frailty are unclear. We investigated the relationship between physical frailty and structural brain abnormalities in 670 cognitively unimpaired individuals (mean age 70.1 years). Total brain volume (TBV), hippocampal volume (HV), total white matter hypointensities volume (WMHV), and estimated total intracranial volume (eTIV) on the 3D T1-weighted images were automatically computed using FreeSurfer software. Participants were divided into two states of physical frailty (robust vs. prefrail) based on the revised Japanese version of the Cardiovascular Health Study criteria. The multivariable-adjusted mean values of the TBV-to-eTIV ratio was significantly decreased, whereas that of the WMHV-to-eTIV ratio was significantly increased in the prefrail group compared with the robust group. Slowness, one of the components of physical frailty, was significantly associated with reduced TBV-to-eTIV and HV-to-eTIV ratios, and slowness and weakness were significantly associated with an increased WMHV-to-eTIV ratio. Our results suggest that the prefrail state is significantly associated with global brain atrophy and white matter hypointensities. Furthermore, slowness was significantly associated with hippocampal atrophy.

Slower maximal walking speed is associated with poorer global cognitive function among older adults residing in China

Background

Maintaining both walking speed and cognitive function is essential for active, healthy aging. This study investigated age-related differences in walking speed and global cognitive function with aging and the association between them among older adults residing in the developing country of China.

Methods

This cross-sectional study measured usual (UWS) and maximal walking speed (MWS) of participants for six meters. The Chinese version of the Montreal Cognitive Assessment was used to evaluate global cognition through in-person interviews. Analyses of variance were used to compare the differences in UWS, MWS, and global cognition between genders and age groups. Multiple linear regression models were used to determine the association between walking speed and global cognitive function.

Results

In total, 791 Chinese adults (252 men and 539 women) aged 60-89 years were included in this study. Markedly slowed UWS and worse global cognitive function scores were observed for both genders among adults ≥80 years of age. MWS slowed considerably in men ≥85 years of age and in women ≥80 years of age. There was a significant gender difference in MWS-with men walking faster than women-but not in UWS. Linear regression analysis adjusted for the confounding factors of gender, height, weight, years of education, and chronic disease indicated that MWS, but not UWS, was significantly associated with global cognitive function (β = 0.086, [0.177, 1.657], P = 0.015) such that slower maximal walking speed was associated with poorer cognitive performance. This association was statistically significant only for adults aged 75-79 years (β = 0.261 [0.647, 4.592], P = 0.010).

Conclusion

Walking speed was slower in the older age groups. Global cognitive function deteriorated markedly after 80 years of age. After controlling for confounding variables, slower MWS, but not UWS, was associated with poorer global cognitive function. MWS may serve as a potential indicator for earlier identification of poor cognition and motoric cognitive risk syndrome in an older Chinese population.

Effects of maximal-versus submaximal-intent resistance training on functional capacity and strength in community-dwelling older adults: a systematic review and meta-analysis

The objective of this systematic review is to investigate the effects of different methods of resistance training (RT) on functional capacity in older adults. A systematic literature search was conducted using PubMed, SPORTDiscus, Web of Science, CINAHL, Cochrane CENTRAL, ClinicalTrials.gov databases, from inception to December 2021. Eligibility criteria consisted of randomised control trials (RCT's) involving maximal-intent resistance training (MIRT), where participants (aged 60+) had specific instruction to move 'as fast as possible' during the concentric phase of the exercise. Twelve studies were included within the meta-analysis. Divided into functional capacity and strength-related outcomes; Improvements were evident for timed-up-and-go (p = 0.001, SMD: - 1.74 [95% CI - 2.79, - 0.69]) and knee extension one-repetition maximum (1RM) (p = 0.01, SMD: - 1.21, [95% CI - 2.17, - 0.25]), both in favour of MIRT, as well as in 30 s sit-to-stand in favour of T-STR (p = 0.04, SMD: 3.10 [95% CI 0.07, 6.14]). No statistical significance was found for combined functional capacity outcomes (p = 0.17, SMD: - 0.84, [95% CI - 2.04, 0.37]), with near-significance observed in strength-related outcomes (p = 0.06. SMD: - 0.57, [95% CI - 1.16, 0.02]) favouring MIRT. Heterogeneity for FC-outcomes was observed as Tau2 = 4.83; Chi = 276.19, df = 14, I2 = 95%, and for strength-outcomes Tau2 = 1.290; Chi = 109.65, df = 115, I2 = 86%. Additionally, MIRT elicited substantial clinically meaningful improvements (CMI) in Short Physical Performance Battery (SPPB) scores but fell short of CMI in 400 m walk test by 0.6 s. In conclusion, this systematic review highlights the lack of sufficient and quality evidence for maximal- versus submaximal-intent resistance training on functional capacity and strength in community-dwelling older adults. Study limitations revolved around lack of research, low quality ("low" PEDro score), and largely due to the fact many comparison studies did not match their loads lifted (1500 kg vs. 500 kg), making comparisons not possible.

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.

Brain health correlates of mobility-related confidence

BACKGROUND

Mobility is important for independence in older age. While brain health correlates of objectively measured mobility-related features like gait and balance have been reported, we aimed to test neuroimaging and cognitive correlates of subjective measures of mobility-related confidence.

METHODS

We carried out a cross-sectional observational study comprised of N = 29 cognitively unimpaired older adult participants, mean age 75.8 ± 5.8, 52% female, 24% non-white. We measured cognition, hippocampal volume, white matter hyperintensities, cerebral amyloid-β (Aβ), and gait and balance confidence. We tested associations using unadjusted Spearman correlations and correlations partialling out covariates of interest one at a time.

RESULTS

Greater gait confidence was associated with better attention (unadjusted ρ = 0.37, p = 0.05; partially attenuated by adjustment for age, APOE4, anxiety, motivation, gait speed, or Aβ); executive performance (unadjusted ρ = 0.35, p = 0.06; partially attenuated by adjustment for age, APOE4, gait speed, or Aβ); and lower Aβ levels (unadjusted ρ = -0.40, p = 0.04; partially attenuated by adjustment for age, depressive symptoms, motivation, or gait speed). Greater balance confidence was associated with better global cognition (unadjusted ρ = 0.41, p = 0.03; partially attenuated by adjustment for APOE4, gait speed, or Aβ); attention (unadjusted ρ = 0.46, p = 0.01; robust to adjustment); and lower Aβ levels (unadjusted ρ = -0.35, p = 0.07; partially attenuated by adjustment for age, education, APOE4, depressive symptoms, anxiety, motivation, or gait speed).

CONCLUSIONS

Self-reported mobility-related confidence is associated with neuroimaging and cognitive measures and would be easy for providers to use in clinical evaluations. These associations should be further evaluated in larger samples, and longitudinal studies can help determine temporality of declines.