Gait in ageing and associated dementias; its relationship with cognition

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.

Attention and sensory integration for gait in young adults with autism spectrum disorder

INTRODUCTION

Altered sensorimotor function is a common feature of autism spectrum disorder (ASD). As a result, spatiotemporal walking patterns are typically affected. Attentional processes relevant for locomotion may be altered in people with ASD. This study assessed the extent to which gait alterations observed under sensory challenging conditions are due to reduced attention-related processes in young adults with ASD.

METHODS

Twenty-one adults with ASD and 21 age- and sex-matched neurotypical participants walked at a self-selected pace on a 10-m walkway under 12 sensory/attention conditions: hard or carpet flooring; well-lit or dim lighting; no attention task, an auditory choice-reaction time information-processing task, or a simple reaction time information-processing task. Gait data were collected with a 12-marker motion capture set and a trunk accelerometer. Spatiotemporal characteristics of gait were derived and compared between the two groups across gait conditions.

RESULTS

Floor/light conditions impacted gait speed, average step length, average stance time, average step width, and step width variability similarly in both groups (p<0.05). The information processing tasks impacted average step length, gait speed, and step length variability (p<0.05). Group differences were found in step length metrics: the ASD group had decreased average step length during the simple reaction time information-processing task and neurotypical participants did not (p=0.039); the ASD group had increased variability on carpet compared to hard floor and the neurotypical group had no change in variability due to floor (p=0.015).

SIGNIFICANCE

These results suggest that attentional set-shifting and somatosensory inputs may play an important role in ASD-related gait alterations. Step length metrics appear to be sensitive to group differences between ASD and neurotypical adults during sensory challenging conditions.

Machine learning approach to classifying declines of physical function and muscle strength associated with cognitive function in older women: gait characteristics based on three speeds

Background

The aging process is associated with a cognitive and physical declines that affects neuromotor control, memory, executive functions, and motor abilities. Previous studies have made efforts to find biomarkers, utilizing complex factors such as gait as indicators of cognitive and physical health in older adults. However, while gait involves various complex factors, such as attention and the integration of sensory input, cognitive-related motor planning and execution, and the musculoskeletal system, research on biomarkers that simultaneously considers multiple factors is scarce. This study aimed to extract gait features through stepwise regression, based on three speeds, and evaluate the accuracy of machine-learning (ML) models based on the selected features to solve classification problems caused by declines in cognitive function (Cog) and physical function (PF), and in Cog and muscle strength (MS).

Methods

Cognitive assessments, five times sit-to-stand, and handgrip strength were performed to evaluate the Cog, PF, and MS of 198 women aged 65 years or older. For gait assessment, all participants walked along a 19-meter straight path at three speeds [preferred walking speed (PWS), slower walking speed (SWS), and faster walking speed (FWS)]. The extracted gait features based on the three speeds were selected using stepwise regression.

Results

The ML model accuracies were revealed as follows: 91.2% for the random forest model when using all gait features and 91.9% when using the three features (walking speed and coefficient of variation of the left double support phase at FWS and the right double support phase at SWS) selected for the Cog+PF+ and Cog-PF- classification. In addition, support vector machine showed a Cog+MS+ and Cog-MS- classification problem with 93.6% accuracy when using all gait features and two selected features (left step time at PWS and gait asymmetry at SWS).

Conclusion

Our study provides insights into the gait characteristics of older women with decreased Cog, PF, and MS, based on the three walking speeds and ML analysis using selected gait features, and may help improve objective classification and evaluation according to declines in Cog, PF, and MS among older women.

Associations of dual-task walking costs with cognition in Parkinson's disease

BACKGROUND

Gait and cognition are closely associated in Parkinson's disease (PD), with specific cognitive domains being associated with different motor symptoms. By identifying gait parameters affected by cognition, clinicians can develop targeted interventions that address cognitive impairment, improve gait, and reduce the risk of injury in PD patients.

RESEARCH QUESTION

What gait parameters are affected by cognition in PD patients during dual-task walking, and how are these parameters related to cognitive function as measured by the Montreal Cognitive Assessment (MoCA)?

METHODS

36 patients with available gait data and cognitive assessments were enrolled. Gait data of usual and dual-task walking sessions were recorded using lightweight wireless wearable sensors attached to trunk, lower, and upper extremities. Dual-task costs were calculated from usual and dual-task measures. Statistical analysis included non-parametric tests, Wilcoxon signed-rank test, Spearman's correlation, and stepwise linear regression models.

RESULTS

Walking speed, cadence, asymmetry in arm swing (ASA), between arms' amplitude symmetry (BAS), average stride time, and jerk of the acceleration movement of the legs were found to be affected during the dual-task walking session (P<0.05). Spearman's correlation showed significant correlations between MoCA scores and ASA (ρ=-0.469, P=0.036) and BAS (ρ=-0.448, P=0.036) costs. Stepwise linear regression models found that MoCA scores were significant predictors of BAS and ASA costs (P<0.05).

SIGNIFICANCE

This study found a significant association between global cognitive ability and several gait parameters costs under cognitive load caused by dual-task walking in PD patients. The study identified the gait parameters that were affected by cognitive load and found that MoCA scores were significant predictors of those gait parameters. Identifying gait parameters affected by cognition can lead to more targeted interventions for improving gait and reducing injury risk in PD patients.

Effect of Vision and Surface Slope on Postural Sway in Healthy Adults: A Prospective Cohort Study

Postural stability requires an interaction between cognitive, perceptual, sensory, and motor functions. Thus, impairment in any of these systems may affect postural balance. This study assessed the effect of visual input and surface slope on postural stability. The study was conducted on healthy participants, 11 females and 11 males who were 24-34 years of age. They were asked to perform still upright bipedal standing on flat and +/-20° sloped surfaces with eyes open (EO) and closed (EC). Six center of pressure (COP) parameters were measured by posturography. A significant relationship was observed between COP parameters, standing conditions, and body mass index. Gender had no significant effect on the COP. The loss of visual input within each standing condition did not affect the COP parameters. In contrast, differences were observed between standing on a flat surface and uphill with EC and between standing on a flat surface and downhill with EC and EO. When the participants were standing on inclined surfaces, the loss of vision significantly increased the postural instability. Young healthy adults demonstrated the greatest difficulty in standing uphill with EC. This was followed by standing downhill with EC and standing downhill with EO.

Gait Characteristics during Dual-Task Walking in Elderly Subjects of Different Ages

BACKGROUND

In older age, walking ability gradually decreases due to factors including impaired balance, reduced muscle strength, and impaired vision and proprioception. Further, cognitive functions play a key role during walking and gradually decline with age. There is greater variability in gait parameters when the demands during walking increase, in dual- and multiple-task situations. The aim of this study was to analyze gait parameters while performing a demanding cognitive and motor dual task in three different age-related healthy elderly subject groups.

METHOD

A total of 132 healthy individuals (54 males, 78 females) were divided into three groups-55 to 65, 66 to 75, and 76 to 85 years. The subjects performed a basic walking task, dual motor task, dual mental task, and combined motor and mental task while walking. The gait parameters cycle time, stride length, swing time, and double support time were noted, as well as the variability of those parameters.

RESULTS

Cycle time was longer and stride length was shorter in the >76-year-old group than in the 51-65-year-old group in all test conditions. A comparison of all three groups did not show a significant difference in swing time, while double support time was increased in the same group.

CONCLUSIONS

Changes are observed when gait is performed simultaneously with an additional motor or cognitive task. Early detection of gait disorders can help identify elderly people at increased risk of falls. Employing a dual-task paradigm during gait assessment in healthy elderly subjects may help identify cognitive impairment early in the course of the disturbance.

Predictive power of gait and gait-related cognitive measures in amnestic mild cognitive impairment: a machine learning analysis

Introduction

Gait disorders and gait-related cognitive tests were recently linked to future Alzheimer's Disease (AD) dementia diagnosis in amnestic Mild Cognitive Impairment (aMCI). This study aimed to evaluate the predictive power of gait disorders and gait-related neuropsychological performances for future AD diagnosis in aMCI through machine learning (ML).

Methods

A sample of 253 aMCI (stable, converter) individuals were included. We explored the predictive accuracy of four predictors (gait profile plus MMSE, DSST, and TMT-B) previously identified as critical for the conversion from aMCI to AD within a 36-month follow-up. Supervised ML algorithms (Support Vector Machine [SVM], Logistic Regression, and k-Nearest Neighbors) were trained on 70% of the dataset, and feature importance was evaluated for the best algorithm.

Results

The SVM algorithm achieved the best performance. The optimized training set performance achieved an accuracy of 0.67 (sensitivity = 0.72; specificity = 0.60), improving to 0.70 on the test set (sensitivity = 0.79; specificity = 0.52). Feature importance revealed MMSE as the most important predictor in both training and testing, while gait type was important in the testing phase.

Discussion

We created a predictive ML model that is capable of identifying aMCI at high risk of AD dementia within 36 months. Our ML model could be used to quickly identify individuals at higher risk of AD, facilitating secondary prevention (e.g., cognitive and/or physical training), and serving as screening for more expansive and invasive tests. Lastly, our results point toward theoretically and practically sound evidence of mind and body interaction in AD.

Association between serum lipid levels and lower-extremity functions in older adults with and without Alzheimer's dementia in South Korea: A cross-sectional analysis

PURPOSE

Older adults with Alzheimer's dementia (AD) experience lower-extremity dysfunction. High serum lipid levels are a risk factor for AD. We investigated the association between serum lipid levels and lower-extremity function in older individuals with and without AD.

METHODS

In this cross-sectional study, we enrolled 33,185 senior citizens (aged 66 years) who participated in the National Geriatric Screening Program, sampled from the Korean National Health Insurance Service-National Health Screening Cohort Database, between 2009 and 2015. Participants were dichotomized into 1) an AD group comprising individuals with the International Classification of Diseases, Tenth Revision, diagnostic codes F00, F00.0-F00.9, and G30, G30.0-G30.9; and 2) a control group comprising individuals without AD. Differences in the Timed Up and Go and One-Leg Standing results among the three levels (low, moderate, and high) of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol were evaluated between the groups. Logistic regression analysis was performed to estimate the odds of gait disorder considering clinical and lifestyle variables.

RESULTS

In participants with low LDL-C levels, increased LDL-C levels correlated with higher gait speed. In the AD group, balancing time with eyes open (BT-EO) was inversely correlated with TG levels in participants with low TG levels. In the control group, BT-EO was negatively correlated with TC levels in participants with low TC levels.

CONCLUSION

Serum lipid levels were significantly correlated with lower-extremity function in participants with and without AD but not with gait disorder in participants with AD.

Gait speed according to cognitive status in older adults: a cross-sectional study in a resource-limited country

OBJECTIVE

We aimed to investigate the association between gait speed and cognitive status in outpatient older adults from a resource-limited setting in Peru.

METHODS

We performed a cross-sectional study including older adults aged ≥60 years attending a geriatrics outpatient clinic between July 2017 and February 2020. Gait speed was measured over a 10-meters distance without considering the first and last meter traveled. Cognitive status was assessed through the Short Portable Mental Status Questionnaire (SPMSQ) and the Mini-Mental State Examination (MMSE). We used a multivariate binomial logistic regression to conduct both an epidemiological and fully adjusted models.

RESULTS

We included 519 older adults (mean age: 75 years; IQR = 10), of whom 95 (18.3%) and 151 (31.5%) were cognitively impaired according to the SPMSQ and MMSE, respectively. Gait speed was slower among patients with poorer cognitive status as assessed by both tools (p < 0.001). Malnutrition (PR: 1.74; CI: 1.45-2.08) and functional dependency (PR: 4.35; CI: 2.68-7.08) were associated with a greater prevalence of cognitive impairment according to the SPMSQ, whereas a faster gait speed (PR: 0.27, CI: 0.14-0.52) and longer years of education (PR: 0.83, CI: 0.77-0.88) were associated with a less prevalence.

CONCLUSIONS

Slower gait speed was associated with poorer cognitive status in outpatient older adults. Gait speed may be a complementary tool in the cognitive assessment of older adults from resource-limited settings.

Prognostic relevance of gait-related cognitive functions for dementia conversion in amnestic mild cognitive impairment

BACKGROUND

Increasing research suggests that gait abnormalities can be a risk factor for Alzheimer's Disease (AD). Notably, there is growing evidence highlighting this risk factor in individuals with amnestic Mild Cognitive Impairment (aMCI), however further studies are needed. The aim of this study is to analyze cognitive tests results and brain-related measures over time in aMCI and examine how the presence of gait abnormalities (neurological or orthopedic) or normal gait affects these trends. Additionally, we sought to assess the significance of gait and gait-related measures as prognostic indicators for the progression from aMCI to AD dementia, comparing those who converted to AD with those who remained with a stable aMCI diagnosis during the follow-up.

METHODS

Four hundred two individuals with aMCI from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database were included. Robust linear mixed-effects models were used to study the impact of gait abnormalities on a comprehensive neuropsychological battery over 36 months while controlling for relevant medical variables at baseline. The impact of gait on brain measures was also investigated. Lastly, the Cox proportional-hazards model was used to explore the prognostic relevance of abnormal gait and neuropsychological associated tests.

RESULTS

While controlling for relevant covariates, we found that gait abnormalities led to a greater decline over time in attention (DSST) and global cognition (MMSE). Intriguingly, psychomotor speed (TMT-A) and divided attention (TMT-B) declined uniquely in the abnormal gait group. Conversely, specific AD global cognition tests (ADAS-13) and auditory-verbal memory (RAVLT immediate recall) declined over time independently of gait profile. All the other cognitive tests were not significantly affected by time or by gait profile. In addition, we found that ventricles size increased faster in the abnormal gait group compared to the normal gait group. In terms of prognosis, abnormal gait (HR = 1.7), MMSE (HR = 1.09), and DSST (HR = 1.03) covariates showed a higher impact on AD dementia conversion.

CONCLUSIONS

The importance of the link between gait and related cognitive functions in terms of diagnosis, prognosis, and rehabilitation in aMCI is critical. We showed that in aMCI gait abnormalities lead to executive functions/attention deterioration and conversion to AD dementia.

Association Between the Loss of Gait Harmony and Cognitive Impairment: Cross-Sectional Study

BACKGROUND

Functional limitations and disabilities have been associated with a decrease in cognitive function due to increasing age. Gait performance and cognitive function have been associated with gait variability in executive function, the phase domain in memory, and gait abnormalities in cognitive decline.

OBJECTIVE

Our study aimed to investigate whether gait harmony was associated with cognitive function in the older adult population. Moreover, we aimed to investigate whether gait harmony was associated with cognitive function and explore each cognitive function in a specific harmonic state.

METHODS

The study population included 510 adults aged ≥60 years who visited the Department of Neurology at the Veterans Health Service Medical Center, Seoul, South Korea. Gait data were collected using a 3D motion capture device with a wireless inertial measurement unit system. For cognitive function assessments, we used the Seoul Neuropsychological Screening Battery-Core test, which evaluates the level of cognitive function or impairment in 5 cognitive domains.

RESULTS

In general, the association between the Seoul Neuropsychological Screening Battery-Core tests and the stance-to-swing ratio in the >1.63 ratio group yielded lower β coefficients than those in the 1.50-1.63 ratio group. After adjustment for confounders, the odds ratio (OR) for the Digit Symbol Coding test (adjusted OR 0.42, 95% CI 0.20-0.88) and the Korean version of the Color Word Stroop Test: 60 seconds (adjusted OR 0.51, 95% CI 0.29-0.89) for frontal and executive function were significantly lower for the >1.63 ratio group than the reference group.

CONCLUSIONS

Our findings suggest that the gait phase ratio is a valuable indicator of walking deficits and may also be associated with cognitive impairment in older adults.

Technology-Assisted Cognitive Motor Dual-Task Rehabilitation in Chronic Age-Related Conditions: Systematic Review

BACKGROUND

Cognitive-motor dual-task (CMDT) is defined as the parallel processing of motor (eg, gait) and cognitive (eg, executive functions) activities and is an essential ability in daily life. Older adults living with frailty, chronic conditions (eg, neurodegenerative diseases), or multimorbidity pay high costs during CMDT. This can have serious consequences on the health and safety of older adults with chronic age-related conditions. However, CMDT rehabilitation can provide useful and effective therapies for these patients, particularly if delivered through technological devices.

OBJECTIVE

This review aims to describe the current technological applications, CMDT rehabilitative procedures, target populations, condition assessment, and efficacy and effectiveness of technology-assisted CMDT rehabilitation in chronic age-related conditions.

METHODS

We performed this systematic review, following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, on 3 databases (Web of Science, Embase, and PubMed). Original articles that were published in English; involved older adults (>65 years) with ≥1 chronic condition and/or frailty; and tested, with a clinical trial, a technology-assisted CMDT rehabilitation against a control condition were included. Risk of bias (Cochrane tool) and the RITES (Rating of Included Trials on the Efficacy-Effectiveness Spectrum) tool were used to evaluate the included studies.

RESULTS

A total of 1097 papers were screened, and 8 (0.73%) studies met the predefined inclusion criteria for this review. The target conditions for technology-assisted CMDT rehabilitation included Parkinson disease and dementia. However, little information regarding multimorbidity, chronicity, or frailty status is available. The primary outcomes included falls, balance, gait parameters, dual-task performance, and executive functions and attention. CMDT technology mainly consists of a motion-tracking system combined with virtual reality. CMDT rehabilitation involves different types of tasks (eg, obstacle negotiation and CMDT exercises). Compared with control conditions, CMDT training was found to be pleasant, safe, and effective particularly for dual-task performances, falls, gait, and cognition, and the effects were maintained at midterm follow-up.

CONCLUSIONS

Despite further research being mandatory, technology-assisted CMDT rehabilitation is a promising method to enhance motor-cognitive functions in older adults with chronic conditions.

What happens behind doors? Exploring everyday indoor activities when ageing in place

Engaging in social interaction and physical movement during everyday activities has a positive influence on wellbeing in later life. For older adults who age in place, the majority of activities occur indoors, yet studies typically focus on outdoors. Gender influences social and physical activities but is understudied in an ageing-in-place context. We aim to address these gaps by increasing insight into the indoor activities in later life, with a focus on gender differences in social interaction and physical movement. Through a mixed-methods approach, data were collected using global positioning system (GPS) trackers, pedometers and activity diaries. Twenty community-dwelling older adults (11 women and 9 men) who were living in Lancashire collected these data over seven days. An exploratory spatio-temporal analysis was conducted on the 820 activities they undertook. We discovered that our participants spend large amounts of time indoors. We also found that social interaction increases the duration of the activity and, conversely, decreases levels of physical movement. When zooming in to gender differences, men's activities took significantly longer than women's activities and were characterised by higher level of social interaction. Based on these results, we argue that there is a trade-off between social interaction and physical movement in everyday activities. We suggest establishing a balance between socialising and moving in everyday activities in later life, specifically because maintaining high levels of movement and social interaction at the same time seems unachievable. In conclusion, it is important to design indoor environments that facilitate choice between being active and resting, and between being social and being on one's own rather than assume they are mutually-exclusive and/or universally "good" or "bad" per se.

Does tandem balance test predict cognitive impairment among older adults? Findings from Longitudinal Ageing Study in India, 2017-18

BACKGROUND

Ageing entails a decline in physical and functional abilities including a reduced body balance due to complex integration and coordination of sensory acuity, motor control, neural and cognitive functions. This study aimed to examine the association between tandem balance test and cognitive impairment among older Indian adults. The study also examined the gender differentials in the associations with an interaction analysis.

METHODS

Data for this study were drawn from the recent release of the Longitudinal Ageing Study in India (2017-18). The total sample size for the present study included 26,539 older adults age 60 years and above. Descriptive statistics and bivariate analysis were used to present the preliminary results. Two sample proportion test was used to evaluate the significance for gender differences. Further, multivariable binary logistic regression analysis was used to evaluate the independent association of balance test performance and cognitive impairment among older adults.

RESULTS

Nearly 16% of male and 26% of female older adults could not finish full tandem test in this study. There were significant gender differences in cognitive impairment among older adults (male-6.5% and female-18.9%). The likelihood of cognitive impairment was significantly higher among older adults who could not finish the full tandem test compared to those who finished the tandem test [AOR: 1.22; CI: 1.09-1.36]. The interaction model revealed that older females who could not finish the full tandem test were 2.11 times significantly more likely to be cognitively impaired in reference to older males who finished the full tandem test [AOR: 2.11; CI: 1.81,2.45]. Similarly, older females who finished the full tandem test were 2.42 times significantly more likely to be cognitively impaired in reference to older males who finished the full tandem test [AOR: 2.42; CI: 2.02,2.88].

CONCLUSION

The findings of the study suggest that healthcare professionals working with older adults should consider the results of a balance test to screen for their risk of cognitive impairment. Results from the relationship between failing to finish the tandem test and cognitive impairment may be helpful for identifying older men and women who are at higher risk of experiencing mobility decline and their progression to dementia.

A Machine Learning Approach for Walking Classification in Elderly People with Gait Disorders

Walking ability of elderly individuals, who suffer from walking difficulties, is limited, which restricts their mobility independence. The physical health and well-being of the elderly population are affected by their level of physical activity. Therefore, monitoring daily activities can help improve the quality of life. This becomes especially a huge challenge for those, who suffer from dementia and Alzheimer's disease. Thus, it is of great importance for personnel in care homes/rehabilitation centers to monitor their daily activities and progress. Unlike normal subjects, it is required to place the sensor on the back of this group of patients, which makes it even more challenging to detect walking from other activities. With the latest advancements in the field of health sensing and sensor technology, a huge amount of accelerometer data can be easily collected. In this study, a Machine Learning (ML) based algorithm was developed to analyze the accelerometer data collected from patients with walking difficulties, who live in one of the municipalities in Denmark. The ML algorithm is capable of accurately classifying the walking activity of these individuals with different walking abnormalities. Various statistical, temporal, and spectral features were extracted from the time series data collected using an accelerometer sensor placed on the back of the participants. The back sensor placement is desirable in patients with dementia and Alzheimer's disease since they may remove visible sensors to them due to the nature of their diseases. Then, an evolutionary optimization algorithm called Particle Swarm Optimization (PSO) was used to select a subset of features to be used in the classification step. Four different ML classifiers such as k-Nearest Neighbors (kNN), Random Forest (RF), Stacking Classifier (Stack), and Extreme Gradient Boosting (XGB) were trained and compared on an accelerometry dataset consisting of 20 participants. These models were evaluated using the leave-one-group-out cross-validation (LOGO-CV) technique. The Stack model achieved the best performance with average sensitivity, positive predictive values (precision), F₁-score, and accuracy of 86.85%, 93.25%, 88.81%, and 93.32%, respectively, to classify walking episodes. In general, the empirical results confirmed that the proposed models are capable of classifying the walking episodes despite the challenging sensor placement on the back of the patients, who suffer from walking disabilities.

Walking Step Monitoring with a Millimeter-Wave Radar in Real-Life Environment for Disease and Fall Prevention for the Elderly

We studied the use of a millimeter-wave frequency-modulated continuous wave radar for gait analysis in a real-life environment, with a focus on the measurement of the step time. A method was developed for the successful extraction of gait patterns for different test cases. The quantitative investigation carried out in a lab corridor showed the excellent reliability of the proposed method for the step time measurement, with an average accuracy of 96%. In addition, a comparison test between the millimeter-wave radar and a continuous-wave radar working at 2.45 GHz was performed, and the results suggest that the millimeter-wave radar is more capable of capturing instantaneous gait features, which enables the timely detection of small gait changes appearing at the early stage of cognitive disorders.

Kinematic strategies for obstacle-crossing in older adults with mild cognitive impairment

Introduction

Mild cognitive impairment (MCI) is considered a transitional stage between soundness of mind and dementia, often involving problems with memory, which may lead to abnormal postural control and altered end-point control when dealing with neuromechanical challenges during obstacle-crossing. The study aimed to identify the end-point control and angular kinematics of the pelvis-leg apparatus while crossing obstacles for both leading and trailing limbs.

Methods

12 patients with MCI (age: 66.7 ± 4.2 y/o; height: 161.3 ± 7.3 cm; mass: 62.0 ± 13.6 kg) and 12 healthy adults (age: 67.7 ± 2.9 y/o; height: 159.3 ± 6.1 cm; mass: 61.2 ± 12.0 kg) each walked and crossed obstacles of three different heights (10, 20, and 30% of leg length). Angular motions of the pelvis and lower limbs and toe-obstacle clearances during leading- and trailing-limb crossings were calculated. Two-way analyses of variance were used to study between-subject (group) and within-subject (obstacle height) effects on the variables. Whenever a height effect was found, a polynomial test was used to determine the trend. A significance level of α = 0.05 was set for all tests.

Results

Patients with MCI significantly increased pelvic anterior tilt, hip abduction, and knee adduction in the swing limb during leading-limb crossing when compared to controls (p < 0.05). During trailing-limb crossing, the MCI group showed significantly decreased pelvic posterior tilt, as well as ankle dorsiflexion in the trailing swing limb (p < 0.05).

Conclusion

Patients with MCI adopt altered kinematic strategies for successful obstacle-crossing. The patients were able to maintain normal leading and trailing toe-obstacle clearances for all tested obstacle heights with a specific kinematic strategy, namely increased pelvic anterior tilt, swing hip abduction, and knee adduction during leading-limb crossing, and decreased pelvic posterior tilt and swing ankle dorsiflexion during trailing-limb crossing. The current results suggest that regular monitoring of obstacle-crossing kinematics for reduced toe-obstacle clearance or any signs of changes in crossing strategy may be helpful for early detection of compromised obstacle-crossing ability in patients with single-domain amnestic MCI. Further studies using a motor/cognitive dual-task approach on the kinematic strategies adopted by multiple-domain MCI will be needed for a complete picture of the functional adaptations in such a patient group.

Identification of causal effects of neuroanatomy on cognitive decline requires modeling unobserved confounders

INTRODUCTION

Carrying out a randomized controlled trial to estimate the causal effects of regional brain atrophy due to Alzheimer's disease (AD) is impossible. Instead, we must estimate causal effects from observational data. However, this generally requires knowing and having recorded all confounders, which is often unrealistic.

METHODS

We provide an approach that leverages the dependencies among multiple neuroanatomical measures to estimate causal effects from observational neuroimaging data without the need to know and record all confounders.

RESULTS

Our analyses of N = 732 $N=732$ subjects from the Alzheimer's Disease Neuroimaging Initiative demonstrate that using our approach results in biologically meaningful conclusions, whereas ignoring unobserved confounding yields results that conflict with established knowledge on cognitive decline due to AD.

DISCUSSION

The findings provide evidence that the impact of unobserved confounding can be substantial. To ensure trustworthy scientific insights, future AD research can account for unobserved confounding via the proposed approach.

Effectiveness of feedback-based technology on physical and cognitive abilities in the elderly

Aging raises a social and health challenge because the passing of time causes changes in cognitive and physical functions that impair functionality and quality of life. In addition, advancements in technology and information technology have led to the development of new techniques for retraining based on the feedback technology provides. To solve the negative consequences of aging, a randomized clinical trial was carried out to assess the effectiveness of a protocol using feedback-based technology to improve physical and cognitive functions in older adults. For the purpose of this study, 200 patients were selected from a Social and Community Services Center in the province of Seville and only 46 of them became participants of the study (after applying the inclusion criteria). These patients were divided into two groups: control and experimental. Physical and cognitive abilities were assessed using the Miniexamen cognoscitivo Test (an adaptation of the MiniMental examination test), Yesevage's Depression Scale, Oddball Test, Attention Network Test, Berg Scale, Tinetti Scale, and Timed Up and Go Test. The intervention applied to the experimental group consisted of a supervised protocol using the Nintendo® Wii video game console and the Wii-Fit© video game during 16 sessions, 2 times a week with a duration of 30 min per session. The control group did not receive any treatment. The experimental group showed statistically significant improvements in all the physical variables (balance, gait, autonomy, and fall risk), as other authors had proven, and in memory and reaction times; there were no improvements in attention networks. The control group (placebo) even showed a decrease in their functions, with worse results on the Timed up and Go test Scale. The intervention using feedback-based technology has been proven effective in improving physical and cognitive abilities and in preventing and promoting healthy aging.

Quantitative gait analysis in mild cognitive impairment, dementia, and cognitively intact individuals: a cross-sectional case-control study

Background

Cognitive age-related decline is linked to dementia development and gait has been proposed to measure the change in brain function. This study aimed to investigate if spatiotemporal gait variables could be used to differentiate between the three cognitive status groups.

Methods

Ninety-three older adults were screened and classified into three groups; mild cognitive impairment (MCI) (n = 32), dementia (n = 31), and a cognitively intact (n = 30). Spatiotemporal gait variables were assessed under single- and dual-tasks using an objective platform system. Effects of cognitive status and walking task were analyzed using a two-way ANCOVA. Sub-comparisons for between- and within-group were performed by one-way ANCOVA and Paired t-tests. Area Under the Curve (AUC) of Receiver Operating Characteristics (ROC) was used to discriminate between three groups on gait variables.

Results

There were significant effects (P < 0.05) of cognitive status during both single and dual-task walking in several variables between the MCI and dementia and between dementia and cognitively intact groups, while no difference was seen between the MCI and cognitively intact groups. A large differentiation effect between the groups was found for step length, stride length, and gait speed during both conditions of walking.

Conclusions

Spatiotemporal gait variables showed discriminative ability between dementia and cognitively intact groups in both single and dual-tasks. This suggests that gait could potentially be used as a clinical differentiation marker for individuals with cognitive problems.

Functional mobility decline and incident mild cognitive impairment and early dementia in community-dwelling older adults: the Singapore Longitudinal Ageing Study

BACKGROUND

Motor and gait disturbances are evident in early Alzheimer and non-Alzheimer dementias and may predict the likelihood of mild cognitive impairment (MCI) or progression to dementia.

OBJECTIVE

We investigated the Timed-Up-and-Go (TUG) measure of functional mobility in predicting cognitive decline and incident MCI or early dementia (MCI-dementia).

DESIGN

Prospective cohort study with 4.5 years follow-up.

SETTING

Population based.

PARTICIPANTS

2,544 community-dwelling older adults aged 55+ years.

METHODS

Participants with baseline data on TUG, fast gait speed (GS), knee extension strength (KES) and performance-oriented mobility assessment (POMA) gait and balance were followed up for cognitive decline (Mini-Mental State Exam; MMSE drop of ≥2, among 1,336 dementia-free participants) and incident MCI-dementia (among 1,208 cognitively normal participants). Odds ratio (OR) and 95% confidence intervals (95% CI) were adjusted for age, sex, education, smoking, physical, social and productive activity, multi-morbidity, metabolic syndrome and MMSE.

RESULTS

Per standard deviation increase in TUG, POMA, GS and KES were significantly associated with incident MCI-dementia: TUG (OR = 2.84, 95% CI = 2.02-3.99), GS (OR = 2.17, 95% CI = 1.62-2.91), POMA (OR = 1.88, 95% CI = 1.22-2.92) and KES (OR = 1.52, 95% CI = 1.15-2.02). Adjusted OR remained significant only for TUG (OR = 1.52, 95% CI = 1.01-2.31) and GS (OR = 1.53, 95% CI = 1.08-2.16). Areas under the curve (AUC) for TUG (AUC = 0.729, 95% CI = 0.671-0.787) were significantly greater than GS (AUC = 0.683, 95% CI = 0.619-0.746), KES (AUC = 0.624, 95% CI = 0.558-0.689) and POMA (AUC = 0.561, 95% CI = 0.485-0.637). Similar associations with cognitive decline were significant though less pronounced, and adjusted ORs remained significant for TUG, GS and POMA.

CONCLUSION

Functional mobility decline precedes incident MCI and early dementia. The TUG appears to be especially accurate in predicting the future risks of adverse cognitive outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03405675. Registered 23 January 2018 (retrospectively registered).

Does Cognitive Training Improve Mobility, Enhance Cognition, and Promote Neural Activation?

A close inter-relationship between mobility and cognition is reported in older adults, with improvements in gait performance noticeable after cognitive remediation in frail individuals. The aim of this study was to evaluate the efficacy of computerized cognitive training (CCT) on mobility in healthy, independently living older adults, and to determine whether CCT is associated with changes in neural activation for mobility-related brain processes. Using a randomized single-blind control design, sixty-three non-demented adults age 60 y and older (mean age = 67 y; 76% female, mean Montreal Cognitive Assessment [MoCA] score = 27) were recruited from a local Senior Activity Center. Participants were randomly assigned to either a 2-month CCT program (8 weeks, 3x/week, 40 min/session) or a wait-list control group. Primary outcome was self-selected gait speed during single- and dual-task walking. Secondary outcome was executive function on Trail Making Test (TMT), Part B. Neural activity was assessed via electroencephalography/event-related potentials (EEG/ERPs) targeting lower-limb performance. Results from a linear mixed effect model, adjusted for baseline MoCA score, age, gender, and study completion revealed that compared to controls, CCT improved gait speed during the dual-task (p = 0.008) but not during the single-task walking condition (p = 0.057). CCT also improved executive function (p = 0.024). Further, shorter foot reaction time responses (p = 0.019) were found with enhanced neural activation over sensorimotor areas, with shorter ERP latencies during the P2 component (p = 0.008) and enhanced motor responses (p = 0.009) also evident in the CCT group after the intervention. Overall, the electrophysiological findings suggest possible neural adaptations that could explain improvements in mobility and executive functions associated with CCT in healthy older adults.

Effects of Cognitive Dysfunction and Dual Task on Gait Speed and Prefrontal Cortex Activation in Community-Dwelling Older Adults

We aimed to determine how prefrontal cortex activation and gait speed during walking is affected by cognitive dysfunction and dual-tasking. Eleven and 14 participants were included in the MOCA-J (Japanese version of the Montreal Cognitive Assessment score) < 26  (age, 76.0 ± 5.7 years; sex, six men and five women) and the MOCA-J ≥ 26 groups (age 73.9 ± 4.3 years; sex, seven men and seven women), respectively. We measured prefrontal cortex oxygenated hemoglobin (oxy-Hb) levels (using Pocket NIRS HM), and gait speed during normal and dual-task walking (a letter fluency task was added). The oxy-Hb levels were significantly lower in the MOCA-J < 26 group than in the MOCA-J ≥ 26 group during dual-task walking. The gait speed was significantly lower during dual-task walking, compared with normal walking, in the MOCA-J < 26group.These results may have been influenced by the compensatory mechanisms in the frontal lobe.

Radiological and functional assessment in patients with lumbar spinal stenosis

Background

Although patients with lumbar spinal stenosis (LSS) may have impaired postural control, current diagnosis of LSS depends mainly on clinical manifestation and radiological assessment, while functional assessment of postural balance remains less investigated. This study thus correlated radiological assessment via MR imaging with functional assessment using foam posturography in LSS patients.

Methods

Forty-seven LSS patients aged 50–85 years were enrolled. All patients received subjective outcome measures first, followed by plain radiography of whole spine and lumbosacral spine, MR imaging, and foam posturography under four conditions. Then, these results were analyzed using stepwise multiple regression analysis. Another 47 age- and sex-matched healthy controls also underwent foam posturography for comparison.

Results

The LSS group revealed significant increases in the sway area of foam posturography than the control group regardless of various conditions. Advanced age, poor walking endurance, and neural compression at the L2/3 level on MR images were significantly correlated with the characteristic parameters of foam posturography (p < 0.05). In contrast, subjectively reported pain and plain radiography did not correlate with posturographic results (p > 0.05).

Conclusions

Patients with LSS who exhibit less severe symptoms do not ensure normal postural balance. Functional assessment (foam posturography) on postural balance significantly correlated with radiological assessment (MR imaging) in LSS patients. The use of foam posturography may help assess postural control in LSS patients. It takes a short time and costs less, and would be practical to make this a routine examination in LSS patients.

Stride-level analysis of mouse open field behavior using deep-learning-based pose estimation

Gait and posture are often perturbed in many neurological, neuromuscular, and neuropsychiatric conditions. Rodents provide a tractable model for elucidating disease mechanisms and interventions. Here, we develop a neural-network-based assay that adopts the commonly used open field apparatus for mouse gait and posture analysis. We quantitate both with high precision across 62 strains of mice. We characterize four mutants with known gait deficits and demonstrate that multiple autism spectrum disorder (ASD) models show gait and posture deficits, implying this is a general feature of ASD. Mouse gait and posture measures are highly heritable and fall into three distinct classes. We conduct a genome-wide association study to define the genetic architecture of stride-level mouse movement in the open field. We provide a method for gait and posture extraction from the open field and one of the largest laboratory mouse gait and posture data resources for the research community.

Sheppard et al. present a method for gait and posture analysis in the common open field apparatus using neural-network-based pose estimation. They apply this high-throughput method to dissect the genetic architecture of mouse movement.

Association of Cognitive Performance with Frailty in Older Individuals with Cognitive Complaints

OBJECTIVES

Frailty is a risk factor for poor cognitive performance in older adults. However, few studies have evaluated the association of cognitive performance with frailty in a low- to middle-income country (LMIC). This study aimed to investigate an association between cognitive performance and frailty in older adults with memory complaints in Brazil. Secondarily, we aim to assess an association of cognitive performance with gait speed and grip strength.

DESIGN

Cross-sectional study.

SETTING

Outpatient service from a LMIC.

PARTICIPANTS

Older adults with memory complaints reported by the participants, their proxies, or their physicians.

MEASUREMENTS

Frailty was evaluated using the Cardiovascular Health Study criteria. A neuropsychological battery evaluated memory, attention, language, visuospatial function, executive function. Linear regression analysis with adjustment for age, sex, and education was used. We also evaluated the interaction of education with frailty, grip strength, and gait speed.

RESULTS

Prefrailty was associated with poor performance in the memory domain, as well as slower gait speed was associated with worse performance in memory, attention, language, and executive function. Frailty and grip strength were not associated with cognitive performance. Interactions of education with gait speed were significant for global performance, as well as for attention and visuospatial ability.

CONCLUSION

In elderly patients with memory complaints, prefrailty was associated with poor memory performance. Slowness was associated with poorer performance in some cognitive domains, mainly in participants with low education.

Dual-Task Gait as a Predictive Tool for Cognitive Impairment in Older Adults: A Systematic Review

The use of the dual-task model as a cognitive-motor interface has been extensively investigated in cross-sectional studies as a training task in cognitive impairment. However, few existing longitudinal studies prove the usefulness of this tool as a clinical marker of cognitive impairment in older people. What is the evidence in prospective studies about dual-task gait as a predictor of cognitive impairment in older adults? This study aims to review and discuss the current state of knowledge in prospective studies on the use of dual-task gait as a predictive tool for cognitive impairment in older adults. The methodology used was a systematic review, according to the PRISMA criteria for the search, summarize and report. A search in 3 databases (Pubmed, Web of Science, and Scopus) was carried out until April 2021. The search terms used were: "(gait OR walking) AND (cognitive decline) AND (dual-task) AND (follow-up OR longitudinal OR long-term OR prospective OR cohort OR predict)." We included prospective research articles with older people with cognitive evaluation at the beginning and the end of the follow-up and dual-task gait paradigm as initial evaluation associated with the presentation of cognitive impairment prediction using any dual-task gait parameters. After exclusion criteria, 12 studies were reviewed. The results indicate that eight studies consider dual-task gait parameters a useful cognitive-motor tool, finding that some of the evaluated parameters of dual-task gait significantly correlate with cognitive impairment over time. The most promising DT parameters associated with cognitive impairment prediction seem to be gait speed, speed cost, DT time, numbers of words during DT, among others. In sum, this study reviews the variety of dual-task gait parameters and their relevance as a simple tool for early cognitive impairment screening, opening a diagnostic window for the screening of cognitive impairment in older people.

Prediction of Decline in Global Cognitive Function Using Machine Learning with Feature Ranking of Gait and Physical Fitness Outcomes in Older Adults

Gait and physical fitness are related to cognitive function. A decrease in motor function and physical fitness can serve as an indicator of declining global cognitive function in older adults. This study aims to use machine learning (ML) to identify important features of gait and physical fitness to predict a decline in global cognitive function in older adults. A total of three hundred and six participants aged seventy-five years or older were included in the study, and their gait performance at various speeds and physical fitness were evaluated. Eight ML models were applied to data ranked by the p-value (LP) of linear regression and the importance gain (XI) of XGboost. Five optimal features were selected using elastic net on the LP data for men, and twenty optimal features were selected using support vector machine on the XI data for women. Thus, the important features for predicting a potential decline in global cognitive function in older adults were successfully identified herein. The proposed ML approach could inspire future studies on the early detection and prevention of cognitive function decline in older adults.

Modeling Functional Limitations, Gait Impairments, and Muscle Pathology in Alzheimer's Disease: Studies in the 3xTg-AD Mice

Gait impairments in Alzheimer's disease (AD) result from structural and functional deficiencies that generate limitations in the performance of activities and restrictions in individual's biopsychosocial participation. In a translational way, we have used the conceptual framework proposed by the International Classification of Disability and Health Functioning (ICF) to classify and describe the functioning and disability on gait and exploratory activity in the 3xTg-AD animal model. We developed a behavioral observation method that allows us to differentiate qualitative parameters of psychomotor performance in animals' gait, similar to the behavioral patterns observed in humans. The functional psychomotor evaluation allows measuring various dimensions of gait and exploratory activity at different stages of disease progression in dichotomy with aging. We included male 3xTg-AD mice and their non-transgenic counterpart (NTg) of 6, 12, and 16 months of age (n = 45). Here, we present the preliminary results. The 3xTg-AD mice show more significant functional impairment in gait and exploratory activity quantitative variables. The presence of movement limitations and muscle weakness mark the functional decline related to the disease severity stages that intensify with increasing age. Motor performance in 3xTg-AD is accompanied by a series of bizarre behaviors that interfere with the trajectory, which allows us to infer poor neurological control. Additionally, signs of physical frailty accompany the functional deterioration of these animals. The use of the ICF as a conceptual framework allows the functional status to be described, facilitating its interpretation and application in the rehabilitation of people with AD.

Imaging-based indices of Neuropathology and gait speed decline in older adults: the atherosclerosis risk in communities study

Imaging markers of cerebrovascular disease and Alzheimer's disease (AD) are implicated in mobility impairment in older adults, but few studies have examined these relationships longitudinally in a racially-diverse population-based sample. At Visit 5 (2011-13) of the ARIC Study, 1859 participants had usual pace gait speed (cm/s) assessed and brain MRI (mean age = 76.3, 28.5% Black) and PET (n = 343; mean age = 75.9, 42.6% Black) measures including total/regional brain volume (cm3), white matter hyperintensities (WMH; cm3), infarcts (present/absent), microbleeds (count) and global beta-amyloid (Aβ). Participants returned at Visit 6 (n = 1264, 2016-17) and Visit 7 (n = 1108, 2018-19) for follow-up gait speed assessments. We used linear regression to estimate effects of baseline infarct presence, higher microbleed count, and a one interquartile range (IQR) poorer measures of continuous predictors (-1 IQR total brain volume, temporal-parietal lobe meta region of interest(ROI); +1 IQR WMH volume, global Aβ SUVR) on cross-sectional gait speed and change in gait speed adjusting for age, sex, education, study site, APOE e4, estimated intracranial volume, BMI, and cardiovascular risk factors. Cross-sectionally, slower gait speed outcome was associated with higher WMH volume, -3.38 cm/s (95%CI:-4.71, -2.04), infarct presence, -5.60 cm/s (-7.69, -3.51), microbleed count, -2.20 cm/s (-3.20, -0.91), smaller total brain volume, -9.26 cm/s (-12.1, -6.43), and smaller temporal-parietal lobe ROI -6.28 cm/s (-8.28, -4.28). Longitudinally, faster gait speed outcome decline was associated with higher WMH volume, -0.27 cm/s/year, (-0.51, -0.03) and higher global Aβ SUVR, -0.62 cm/s/year (-1.20, -0.03). Both cerebrovascular and AD pathology may contribute to mobility decline commonly seen with aging.

Kyphosis and bizarre patterns impair spontaneous gait performance in end-of-life mice with Alzheimer's disease pathology while gait is preserved in normal aging

The shorter life spans of mice provide an exceptional experimental gerontology scenario. We previously described increased bizarre (disruptive) behaviors in the 6-month-old 3xTg-AD mice model for Alzheimer's disease (AD), compared to C57BL/6J wildtype (NTg), when confronting new environments. In the present work, we evaluated spontaneous gait and exploratory activity at old age, using 16-month-old mice. Male sex was chosen since sex-dependent psychomotor effects of aging are stronger in NTg males than females and, at this age, male 3 × Tg-AD mice are close to an end-of-life status due to increased mortality rates. Mice's behavior was evaluated in a transparent test box during the neophobia response. Stretching, jumping, backward movements and bizarre circling were identified during the gait and exploratory activity. The results corroborate that in the face of novelty and recognition of places, old 3xTg-AD mice exhibit increased bizarre behaviors than mice with normal aging. Furthermore, bizarre circling and backward movements delayed the elicitation of locomotion and exploration, in an already frail scenario, as shown by highly prevalent kyphosis in both groups. Thus, the translational study of co-occurrence of psychomotor impairments and anxiety-like behaviors can be helpful for understanding and managing the progressive functional deterioration shown in aging, especially in AD.

Associations between vitamin E, oxidative stress markers, total homocysteine levels, and physical activity or cognitive capacity in older adults

This study examined the associations between vitamin E, oxidative stress markers, total homocysteine levels, and physical activity or cognitive capacity in older adults. One hundred and six older adults (62 men, 44 women) within the age range of 56-81 years participated. The Global Physical Activity Questionnaire and the Loewenstein Occupational Therapy Cognitive Assessment were used to assess physical activity and cognitive function, respectively. Vitamin E (e.g., α-tocopherol and γ-tocopherol), oxidative stress markers (e.g., total antioxidant capacity and nitric oxide), and total homocysteine were estimated. There were significant associations between physical activity (high versus moderate versus poor) and all biomarkers (all p = 0.000, and p = 0.010 for γ-tocopherol). While total homocysteine and total antioxidant capacity were significantly associated with cognitive capacity (p = 0.000), vitamin E levels (e.g., α-tocopherol and γ-tocopherol) and nitric oxide (p = 0.354, 0.103 and 0.060, respectively) were not related to cognitive capacity in older adults. This study concludes that physical activity was associated with Vitamin E, oxidative stress markers, total homocysteine, and cognitive capacity in older adults. Although cognitive capacity was associated with total homocysteine and total antioxidant capacity, it was unrelated to vitamin E levels and nitric oxide in older adults.

Gait Disturbances are Associated with Increased Cognitive Impairment and Cerebrospinal Fluid Tau Levels in a Memory Clinic Cohort

Background:

Gait analysis with accelerometers is a relatively inexpensive and easy to use method to potentially support clinical diagnoses of Alzheimer’s disease and other dementias. It is not clear, however, which gait features are most informative and how these measures relate to Alzheimer’s disease pathology.

Objective:

In this study, we tested if calculated features of gait 1) differ between cognitively normal subjects (CN), mild cognitive impairment (MCI) patients, and dementia patients, 2) are correlated with cerebrospinal fluid (CSF) biomarkers related to Alzheimer’s disease, and 3) predict cognitive decline.

Methods:

Gait was measured using tri-axial accelerometers attached to the fifth lumbar vertebra (L5) in 58 CN, 58 MCI, and 26 dementia participants, while performing a walk and dual task. Ten gait features were calculated from the vertical L5 accelerations, following principal component analysis clustered in four domains, namely pace, rhythm, time variability, and length variability. Cognitive decline over time was measured using MMSE, and CSF biomarkers were available in a sub-group.

Results:

Linear mixed models showed that dementia patients had lower pace scores than MCI patients and CN subjects (p < 0.05). In addition, we found associations between the rhythm domain and CSF-tau, especially in the dual task. Gait was not associated with CSF Aβ₄₂ levels and cognitive decline over time as measured with the MMSE.

Conclusion:

These findings suggest that gait — particularly measures related to pace and rhythm — are altered in dementia and have a direct link with measures of neurodegeneration.

Motoric cognitive risk syndrome and incident dementia in older adults from the Québec NuAge cohort

BACKGROUND

The co-occurrence of slow walking speed and subjective cognitive complaint (SCC) in non-demented individuals defines motoric cognitive risk syndrome (MCR), which is a pre-dementia stage. There is no information on the association between MCR and incident dementia in Québec's older population.

OBJECTIVE

The study aims to examine the association of MCR and its individual components (i.e. SCC and slow walking speed) with incident dementia in community-dwelling older adults living in the province of Québec (Canada).

DESIGN

Québec older people population-based observational cohort study with 3 years of follow-up.

SETTING

Community dwellings.

SUBJECTS

A subset of participants (n = 1,098) in 'Nutrition as a determinant of successful aging: The Québec longitudinal study' (NuAge).

METHODS

At baseline, participants with MCR were identified. Incident dementia was measured at annual follow-up visits using the Modified Mini-Mental State (≤79/100) test and Instrumental Activity Daily Living scale (≤6/8) score values.

RESULTS

The prevalence of MCR was 4.2% at baseline and the overall incidence of dementia was 3.6%. MCR (Hazard Ratio (HR) = 5.18, with 95% confidence interval (CI) = [2.43-11.03] and P ≤ 0.001) and SCC alone (HR = 2.54, with 95% CI = [1.33-4.85] and P = 0.005) were associated with incident dementia, but slow walking speed was not (HR = 0.81, with 95%CI = [0.25-2.63] and P = 0.736).

CONCLUSIONS

MCR and SCC are associated with incident dementia in NuAge study participants.

Translational Modeling of Psychomotor Function in Normal and AD-Pathological Aging With Special Concerns on the Effects of Social Isolation

One year after the start of the COVID-19 pandemic, its secondary impacts can be globally observed. Some of them result from physical distancing and severe social contact restrictions by policies still imposed to stop the fast spread of new variants of this infectious disease. People with Alzheimer's disease (AD) and other dementias can also be significantly affected by the reduction of their activity programs, the loss of partners, and social isolation. Searching for the closest translational scenario, the increased mortality rates in male 3xTg-AD mice modeling advanced stages of the disease can provide a scenario of “naturalistic isolation.” Our most recent work has shown its impact worsening AD-cognitive and emotional profiles, AD-brain asymmetry, and eliciting hyperactivity and bizarre behaviors. Here, we further investigated the psychomotor function through six different psychomotor analysis in a set of 13-month-old 3xTg-AD mice and their non-transgenic counterparts with normal aging. The subgroup of male 3xTg-AD mice that lost their partners lived alone for the last 2–3 months after 10 months of social life. AD's functional limitations were shown as increased physical frailty phenotype, poor or deficient psychomotor performance, including bizarre behavior, in variables involving information processing and decision-making (exploratory activity and spontaneous gait), that worsened with isolation. Paradoxical muscular strength and better motor performance (endurance and learning) was shown in variables related to physical work and found enhanced by isolation, in agreement with the hyperactivity and the appearance of bizarre behaviors previously reported. Despite the isolation, a delayed appearance of motor deficits related to physical resistance and tolerance to exercise was found in the 3xTg-AD mice, probably because of the interplay of hyperactivity and mortality/survivor bias. The translation of these results to the clinical setting offers a guide to generate flexible and personalized rehabilitation strategies adaptable to the restrictions of the COVID-19 pandemic.

Attention and sensory integration for postural control in young adults with autism spectrum disorders

Postural control impairments have been reported in adults with autism spectrum disorders (ASD). Balance relies on the integration of multisensory cues, a process that requires attention. The purpose of this study was to determine if the influence of attention demands on sensory integration abilities relevant for balance partially contributes to postural control impairments in ASD. Young adults with ASD (N = 24) and neurotypical participants (N = 24) were exposed to sensory perturbations during standing. An established dual-task paradigm was used, requiring participants to maintain balance in these sensory challenging environments and to perform auditory information processing tasks (simple reaction time task and choice reaction time task). Balance was assessed using sway magnitude and sway speed, and attention demands were evaluated based on the response time in the auditory tasks. While young adults with ASD were able to maintain balance in destabilizing sensory conditions, they were more challenged (greater sway speed) than their neurotypical counterparts. Additionally, when exposed for an extended amount of time (3 min) to the most challenging sensory condition included in this study, adults with ASD exhibited a reduced ability to adapt their postural control strategies (sway speed was minimally reduced), demonstrating a postural inflexibility pattern in ASD compared to neurotypical counterparts. Finally, the impact of performing an auditory information processing task on balance and the dual-task cost on information processing (response time) was similar in both groups. ASD may disrupt temporal adaptive postural control processes associated with sensory reweighting that occurs in neurotypicals.

Gait Analysis under Spatial Navigation Task in Elderly People-A Pilot Study

A decline in the Spatial Navigation (SN) abilities has been observed in the course of healthy aging. Walking is an inseparable part of the navigation process; however, research tasks overlook this aspect in studies involving seniors. The present study was designed to overcome this limitation by recording gait parameters during natural environment navigation and to determine gait indicators that most accurately assign the participants to the proper age category. Thirteen elderly (mean age = 69.1 ± 5.4 year) and sixteen young women (mean age = 21.5 ± 2.2 year) equipped with gait sensors were asked to learn a path while walking in a real building (Learning Phase), reproduce the path (Memory Phase) and reach targets after a 30 min delay (Delayed Phase). The Receiver Operating Characteristics (ROC) analysis showed that our self-developed Gait Style Change indicator, that is, the difference in the probability of feet landing between particular SN task phases, classified the participants into either the elderly or the young group with the highest accuracy (0.91). The second most important indicator, the Task-Related (step counts in each SN task phase), achieved the accuracy discrimination of 0.83. The gait indicators, comprising single gait parameters measured while navigating, might be considered as accurately differentiating older from younger people.

Current Perspectives on the Assessment and Management of Gait Disorders in Parkinson's Disease

Gait dysfunction is a key defining feature of Parkinson's disease (PD), and is associated with symptoms of freezing and an increased risk of falls. In this narrative review, we cover the putative mechanisms of gait dysfunction in PD, the assessment of gait abnormalities, and the management of symptoms caused by the inherent difficulty in walking. Our understanding of the causes of gait problems in PD has progressed in recent times, moving from neurocognitive theory to correlates of affected neuronal pathways. In particular, this can be shown to correspond with abnormalities in responses to dual-task paradigms and dysfunction in cholinergic signaling. Great progress has been made in the sophistication and precision of gait assessment; however, it has firmly remained in the research domain. There is significant momentum behind wearable technologies that can be used by patients in their own environment, acting as digital biomarkers that can not only reflect progression but also independently discriminate PD from non-PD individuals. The treatment of gait dysfunction has historically relied on physical therapies and training combined with a view to mitigating the impact of such consequences as falls. Pharmacological therapies that are the mainstay of treatment in PD have tended to address symptoms like bradykinesia; however, optimization of dopaminergic therapies likely has a positive effect on quality of gait. Other targets have been assessed with the goal of improving gait, of which medications that improve cholinergic signaling appear most promising. Neuromodulation techniques are increasingly used in the form of deep-brain stimulation; however, standard targets, such as the globus pallidus interna, have a modest effect on gait. Considerable benefit has been seen through targeting the pedunculopontine nucleus, and a dual-target approach may be warranted. Stimulation of the spinal cord and brain through direct or magnetic approaches has been assessed, but requires further evidence.

Association Between Motor and Cognitive Performances in Elderly With Atrial Fibrillation: Strat-AF Study

Background/Objective: Growing evidence suggests a close relationship between motor and cognitive abilities, but possible common underlying mechanisms are not well-established. Atrial fibrillation (AF) is associated with reduced physical performance and increased risk of cognitive decline. The study aimed to assess in a cohort of elderly AF patients: (1) the association between motor and cognitive performances, and (2) the influence and potential mediating role of cerebral lesions burden.

Design: Strat-AF is a prospective, observational study investigating biological markers for cerebral bleeding risk stratification in AF patients on oral anticoagulants. Baseline cross-sectional data are presented here.

Setting: Thrombosis outpatient clinic (Careggi University Hospital).

Participants: One-hundred and seventy patients (mean age 77.7 ± 6.8; females 35%).

Measurements: Baseline protocol included: neuropsychological battery, motor assessment [Short Physical Performance Battery (SPPB), and walking speed], and brain magnetic resonance imaging (MRI) used for the visual assessment of white matter hyperintensities, lacunar and non-lacunar infarcts, cerebral microbleeds, and global cortical and medial temporal atrophies.

Results: Mean Montreal Cognitive Assessment (MoCA) total score was 21.9 ± 3.9, SPPB total score 9.5 ± 2.2, and walking speed 0.9 ± 0.2. In univariate analyses, both SPPB and walking speed were significantly associated with MoCA (r = 0.359, r = 0.372, respectively), visual search (r = 0.361, r = 0.322), Stroop (r = −0.272, r = −0.263), short story (r = 0.263, r = 0.310), and semantic fluency (r = 0.311, r = 0.360). In multivariate models adjusted for demographics, heart failure, physical activity, and either stroke history (Model 1) or neuroimaging markers (Model 2), both SPPB and walking speed were confirmed significantly associated with MoCA (Model 1: β = 0.256, β = 0.236; Model 2: β = 0.276, β = 0.272, respectively), visual search (Model 1: β = 0.350, β = 0.313; Model 2: β = 0.344, β = 0.307), semantic fluency (Model 1: β = 0.223, β = 0.261), and short story (Model 2: β = 0.245, β = 0.273).

Conclusions: In our cohort of elderly AF patients, a direct association between motor and cognitive functions consistently recurred using different evaluation of the performances, without an evident mediating role of cerebral lesions burden.

Gait Parameter Estimation of Elderly People using 3D Human Pose Estimation in Early Detection of Dementia

Early detection of dementia is becoming increasingly important as it plays a crucial role in handling the patients and offering better treatment. Many of the recent studies concluded a tight relationship between dementia and gait disorders. For this purpose, identification of gait abnormalities is key factor. Novel technologies provide many options such as wearable and non-wearable approaches for analysis of gait. As the occurrence of dementia is more prominent in elderly people, wearable technology is considered out of scope for this work. The gait data of several elderly people over 80 years is acquired over certain intervals during the scope of the project. The elderly people are classified into three study groups namely cognitively healthy individuals (CHI), subjectively cognitively impaired persons (SCI) and possible mildly cognitively impaired persons due to inconclusive test results (pMCI) based on their cognitive status. The gait data is acquired using Kinect sensor. The acquired data consists of both RGB image sequences and depth data of the test persons. 3D human pose estimation is performed on this gait data and gait analysis is done. The transformations in the gait cycles are observed and the health condition of the individual is analyzed. From the analysis, the patterns in the gait abnormalities are correlated with the above-mentioned classification and are used in the detection of dementia in advance. The obtained results look promising and further analysis of gait parameters is under progress.

Dual-Task Gait Assessment and Machine Learning for Early-detection of Cognitive Decline

Alzheimer's disease (AD) affects approximately 30 million people worldwide, and this number is predicted to triple by 2050 unless further discoveries facilitate the early detection and prevention of the disease. Computerized walkways for simultaneous assessment of motor-cognitive performance, known as a dual-task assessment, has been used to associate changes in gait characteristics to mild cognitive impairment (MCI) with early-stage disease. However, to our best knowledge, there is no validated method to detect MCI using the collective analysis of these gait characteristics. In this paper, we develop a machine learning approach to analyze the gait data from the dual-task assessment in order to detect subjects with cognitive impairment from healthy individuals. We collected dual-task gait data from a computerized walkway of a total of 92 subjects with 31 healthy control (HC) and 61 MCI. Using support vector machine (SVM) and gradient tree boosting, we developed a classifier to differentiate MCI from HC subjects and compared the results with a paper-based questionnaire assessment that has been commonly used in clinical practice. SVM provided the highest accuracy of 77.17% with 81.97% sensitivity and 67.74% specificity. Our results indicate the potential of machine learning + dual-task assessment to enable early diagnosis of cognitive decline before it advances to dementia and AD, so that early intervention or prevention strategies can be initiated.

Physical Frailty Phenotype Criteria and Their Synergistic Association on Cognitive Functioning

BACKGROUND

Frailty (physical frailty phenotype [PFP]) and its criteria (slow gait, weakness, weight loss, low activity, and exhaustion) are each associated with cognitive dysfunction. The extent to which the PFP is associated with cognition beyond that expected from its component parts remains uncertain.

METHOD

We used the National Health and Aging Trends Study to quantify associations between PFP criteria and cognitive performance (level/change) using adjusted mixed effects models. We tested whether frailty was associated with excess cognitive vulnerability (synergistic/excess effects, Cohen's d) beyond criteria contributions by assessing interactions between each criterion and frailty.

RESULTS

Among 7439 community-dwelling older adults (mean age = 75.2 years) followed for a mean of 3.2 years (SE = 0.03), 14.1% were frail. The PFP and PFP criteria were all associated with lower baseline cognitive performance, among which slow gait (-0.31 SD, SE = 0.02) and frailty (-0.23 SD, SE = 0.02) were strongest. Only slow gait (-0.03 SD/year, SE = 0.01), frailty (-0.02 SD/year, SE = 0.01), weight loss (-0.02 SD/year, SE = 0.01), and weakness (-0.02 SD/year, SE = 0.01) were associated with cognitive decline. Frailty was associated with cognitive performance above and beyond each criterion (excess effects ranging from -0.07 SD [SE = -0.05] for slow gait to -0.23 SD [SE = 0.03] for weakness); the same was not true for cognitive decline. Slow gait was the only criterion associated with cognitive change among both frail and nonfrail participants (frail: Cohen's d/year = -0.03, SE = 0.01; nonfrail: Cohen's d/year = -0.02, SE = 0.01).

CONCLUSIONS

PFP is an important frailty measure that is cross-sectionally associated with lower cognitive performance, but not with subsequent cognitive decline, above and beyond its criteria contributions. Further research into the construct of frailty as a "syndrome" correlated with cognition and other adverse outcomes is needed.

Center of pressure displacement characteristics differentiate fall risk in older people: A systematic review with meta-analysis

Falling is the second most prevalent cause of accidental death in the world. Currently available clinical tests to assess balance in older people are insufficiently sensitive to screen for fall risk in this population. Laboratory tests that record the center of pressure (COP) trajectory could overcome this problem but despite their widespread use, the choice of COP trajectory features for use as a biomarker of fall risk lacks consensus. This systematic review and meta-analysis aimed at identifying the best COP characteristics to predict risk of falling in older adults. More than 4000 articles were screened; 44 (7176 older adults) were included in this study. Several COP parameters emerged as good indices to discriminate fallers from non-fallers. From sensitivity analysis, Sway area per unit time, anteroposterior mean velocity, and radial mean velocity were the best traditional features. In this study, identification of older people with a high fall risk was demonstrated using quiet-standing recordings. Such screening would also be useful for routine follow-up of balance changes in older fallers in clinical practice.

Motor Impairment Three Months Post Stroke Implies A Corresponding Cognitive Deficit

BACKGROUND

While both motor and cognitive impairment are common after stroke, the focus of (early) treatment has always been on motor deficit.

AIMS

The objective of the current study was to explore the link between motor and cognitive performance in stroke patients and to examine whether motor performance is associated with cognitive functioning at three months post stroke.

METHODS

In both stroke patients (n = 142) and controls (n = 135), with the groups matched on age, gender and premorbid IQ, motor functioning was evaluated using both objective (Purdue Pegboard Test) and subjective measures (specific items from the Frenchay Activities Index and Barthel Index). Cognition, specifically information processing speed, working memory and cognitive flexibility, was assessed using objective tasks. The data were analyzed using Pearson product-moment correlation coefficients and logistic regression.

RESULTS

Significant correlations between motor and cognitive functioning were found in stroke patients. The objective motor task was stronger than subjective measures in statistically explaining and predicting cognitive deficit, irrespective of stroke severity.

CONCLUSIONS

We conclude that motor impairment at three months post-stroke should serve as a 'red flag' for professionals: cognitive impairment is likely and should also be evaluated.

Deep learning with long short-term memory networks for classification of dementia related travel patterns

Wandering pattern classification is important for early recognition of cognitive deterioration and other health conditions in people with dementia (PWD). In this paper, we leverage the orientation data available on mobile devices to recognize dementia-related wandering patterns. In particular, we propose to use deep learning (DL) with long short-term memory networks (LSTM) as classifiers for detecting travel patterns including direct, pacing, lapping and random. Experimental results on a real dataset collected from 14 subjects show that deep LSTM classifiers perform better than traditional machine learning (ML) classifiers. Our proposed method can thus be potentially used in healthcare applications for dementia related wandering monitoring and management.Clinical Relevance- This demonstrates the potential of using readily available yet non-privacy information to detect dementia-related wandering patterns with high accuracy.

The association of anxio-depressive disorders and depression with motoric cognitive risk syndrome: results from the baseline assessment of the Canadian longitudinal study on aging

Motoric cognitive risk syndrome (MCR), anxio-depressive disorders (ADD), and depression are associated with cognitive complaint and slow gait speed. The study aims to examine (1) the association of ADD and depression with MCR, and (2) the influence of the type and the severity of ADD and age on this association in older adults. A total of 29,569 participants free from cognitive impairment with walking speed measure recruited at baseline in the Canadian Longitudinal Study on Aging (CLSA) Comprehensive were selected in this cross-sectional study. They were separated into different sub-groups based on their age groups (i.e., 45-54, 55-64, 65-74, and ≥ 75) and the presence of MCR. Anxiety, mood, and depressive disorders (ADD) were assessed. Depression was defined by the Center for Epidemiological Studies Depression Scale (CES-D) score ≥ 10. The overall prevalence of MCR was 7.0 % and was greater in the youngest age group (8.9 %) as compared to the other age groups (P < 0.05). There was a higher prevalence of ADD and depression in individuals with MCR compared to those without MCR for all age groups (P ≤ 0.001). Depression was significantly associated with MCR regardless of age group (odds ratio ≥ 3.65 with P ≤ 0.001). The association of ADD with MCR depended on the accumulation of disorders and not their type, and was weaker and more inconstant in the oldest age group as compared to younger age groups. MCR is associated with ADD and depression in both younger and older individuals. This association is stronger for depression in younger individuals.

Pre-frontal Cortical Activity During Walking and Turning Is Reliable and Differentiates Across Young, Older Adults and People With Parkinson's Disease

Introduction: Mobility declines with age and further with neurodegenerative disorders, such as Parkinson's disease (PD). Walking and turning ability, in particular, are vital aspects of mobility that deteriorate with age and are further impaired in PD. Such deficits have been linked with reduction in automatic control of movement and the need for compensatory cognitive cortical control via the pre-frontal cortex (PFC), however the underlying neural mechanisms remain unclear. Establishing and using a robust methodology to examine PFC activity during continuous walking and turning via mobile functional near infra-red spectroscopy (fNIRS) may aid in the understanding of mobility deficits and help with development of appropriate therapeutics. This study aimed to: (1) examine test re-test reliability of PFC activity during continuous turning and walking via fNIRS measurement; and (2) compare PFC activity during continuous turning and walking in young, old and Parkinson's subjects. Methods: Twenty-five young (32.3 ± 7.5 years), nineteen older (65.4 ± 7.0 years), and twenty-four PD (69.3 ± 4.1 years) participants performed continuous walking and 360° turning-in-place tasks, each lasting 2 min. Young participants repeated the tasks a second time to allow fNIRS measurement reliability assessment. The primary outcome was PFC activity, assessed via measuring changes in oxygenated hemoglobin (HbO₂) concentrations. Results: PFC activity during continuous walking and turning was moderately reproducible (Intra-class correlation coefficient = 0.67). The PD group had higher PFC activation than young and older adults during walking and turning, with significant group differences for bilateral PFC activation (p = 0.025), left PFC activation (p = 0.012), and the early period (first 40 s) of walking (p = 0.007), with greater activation required in PD. Interestingly, older adults had similar PFC activation to young adults across conditions, however older adults required greater activation than young adults during continuous turning, specifically the early period of the turning task (Cohens d = 0.86). Conclusions: PFC activity can be measured during continuous walking and turning tasks with acceptable reliability, and can differentiate young, older and PD groups. PFC activation was significantly greater in PD compared to young and older adults during walking, particularly when beginning to walk.