Talking while walking: the effect of a dual task in aging and Alzheimer's disease

Cognitive function influences cognitive-motor interference during dual task walking in multiple sclerosis

BACKGROUND

Both physical and cognitive impairments are common in people with multiple sclerosis (PwMS). Performing a cognitive task while walking (i.e., dual-task walking) can introduce cognitive-motor interference (CMI), resulting in changes in walking performance. The association between the levels of cognitive impairment and of CMI in MS remains unclear.

OBJECTIVES

To examine the association between cognitive functioning and differences in walking performance arise between single- and dual-task walking.

METHODS

Ninety-five PwMS performed self-preferred pace walking and dual-task walking. The gait parameters recorded were used to compute dual task costs (DTC) as a metric of CMI. Cognitive functioning was assessed using Match, an unsupervised test developed based on the Symbol Digit Modalities Test. Participants were categorized as higher (HCF) and lower cognitive functioning (LCF) based on a Match z-score < -1.5.

RESULTS

LCF group had elevated DTC for stride velocity, relative to the HCF group. Higher DTC for stride velocity was associated with lower cognition, as assessed by Match test.

CONCLUSION

The findings support the hypothesis that CMI is associated with cognitive functioning in PwMS.

Gray matter loss relates to dual task gait in Lewy body disorders and aging

BACKGROUND

Within the spectrum of Lewy body disorders (LBD), both Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are characterized by gait and balance disturbances, which become more prominent under dual-task (DT) conditions. The brain substrates underlying DT gait variations, however, remain poorly understood in LBD.

OBJECTIVE

To investigate the relationship between gray matter volume loss and DT gait variations in LBD.

METHODS

Seventy-nine participants including cognitively unimpaired PD, PD with mild cognitive impairment, PD with dementia (PDD), or DLB and 20 cognitively unimpaired controls were examined across a multi-site study. PDD and DLB were grouped together for analyses. Differences in gait speed between single and DT conditions were quantified by dual task cost (DTC). Cortical, subcortical, ventricle, and cerebellum brain volumes were obtained using FreeSurfer. Linear regression models were used to examine the relationship between gray matter volumes and DTC.

RESULTS

Smaller amygdala and total cortical volumes, and larger ventricle volumes were associated with a higher DTC across LBD and cognitively unimpaired controls. No statistically significant interaction between group and brain volumes were found. Adding cognitive and motor covariates or white matter hyperintensity volumes separately to the models did not affect brain volume and DTC associations.

CONCLUSION

Gray matter volume loss is associated with worse DT gait performance compared to single task gait, across cognitively unimpaired controls through and the LBD spectrum. Impairment in DT gait performance may be driven by age-related cortical neurodegeneration.

Cognitive-motor dual-task interference in Alzheimer's disease, Parkinson's disease, and prodromal neurodegeneration: A scoping review

BACKGROUND

Cognitive-motor interference (CMI) is a common deficit in Alzheimer's (AD) disease and Parkinson's disease (PD) and may have utility in identification of prodromal neurodegeneration. There is lack of consensus regarding measurement of CMI resulting from dual task paradigms.

RESEARCH QUESTION

How are individuals with AD, PD, and prodromal neurodegeneration impacted by CMI as measured by dual-task (DT) performance?

METHODS

A systematic literature search was performed in six datasets using the PRISMA guidelines. Studies were included if they had samples of participants with AD, PD, or prodromal neurodegeneration and reported at least one measure of cognitive-motor DT performance.

RESULTS

4741 articles were screened and 95 included as part of this scoping review. Articles were divided into three non-mutually exclusive groups based on diagnoses, with 26 articles in AD, 56 articles in PD, and 29 articles in prodromal neurodegeneration, and results presented accordingly.

SIGNIFICANCE

Individuals with AD and PD are both impacted by CMI, though the impact is likely different for each disease. We found a robust body of evidence regarding the utility of measures of DT performance in the detection of subtle deficits in prodromal AD and some signals of utility in prodromal PD. There are several key methodological challenges related to DT paradigms for the measurement of CMI in neurodegeneration. Overall, DT paradigms show good potential as a clinical method to probe specific brain regions, networks, and function; however, task selection and effect measurement should be carefully considered.

Comparing the effect of individual and group cognitive-motor training on reconstructing subjective well-being and quality of life in older males, recovered from the COVID-19

While the message emanating from physiological and psychological research has extolled the general advantages of exercise in physical and cognitive health, the social distancing and the impossibility of group exercises have revealed more complex conditions. Therefore, we performed an experimental study comparing the effect of individual and group cognitive-motor training on reconstructing subjective well-being (SWB) and quality of life (QOL) in older males who recovered from COVID-19. The study's design is a single-blind, randomized controlled trial (RCT). The participants, 36 older men (65-80 yrs.) recovering from COVID-19, were randomly divided into (1) Group A (cognitive-motor training, G-CMT); (2) Group B (individual cognitive-motor training, I-CMT); and (3) Group C (control). Both training interventions involved performing a training protocol (cognitive-motor training) twice a week for four weeks. The outcomes included an assessment of the SWB and QOL of participants by SWB scale and world health organization QOL scale at baseline and two weeks after interventions. Except for the effect of age and number of children variables on QOL, other demographic variables had no significant effect on the results of SWB or WHOQOL of participants (P > 0.05). The SWB results in G-CMT were better than I-CMT and control groups in emotional and social well-being domains. Also, WHOQOL test results in G-CMT were better than control groups in domains of psychological and social relationships, whereas I-CMT performed better than G-CMT and control groups in domains of cognitive well-being, physical health, and environment. The results revealed that the mean test scores of SWB and WHOQOL in G-CMT and I-CMT were better than the control group (P ≤ 0.001). The positive effects of cognitive-motor training on reconstructing SWB and QOL are associated with the synchronicity of cognitive and motor components in these exercises. We suggest that the emotional, social, and psychological benefits of cognitive-motor training override cognitive, physical, and environmental changes. The future line of the present study will include pathophysiology and further clinical aspect of recovering from COVID-19.

Association between dual-task function and neuropsychological testing in older adults with cognitive impairment

INTRODUCTION

Despite the current high prevalence of dementia, more than half of older adult patients never receive an evaluation. Current evaluation methods are lengthy, cumbersome, and not viable for busy clinics. This indicates that, despite recent improvements, a quick and objective routine test for screening cognitive decline in older adults is still needed. Poor dual-task gait performance has been previously associated with decreased executive and neuropsychological function. However, gait tests are not always viable for clinics or older patients.

METHODS

The aim of this study was to assess the relationship between a novel upper-extremity function (UEF) dual-task performance and neuropsychological test results in older adults. For UEF dual-tasks, participants performed a consistent elbow flexion and extension, while counting backwards in increments of threes or ones. Wearable motion sensors were attached to the forearm and upper-arm to measure accuracy and speed of elbow flexion kinematics to calculate a UEF cognitive score.

RESULTS

We recruited older adults at three stages: cognitively normal (CN) (n = 35), mild cognitively impaired (MCI) of the Alzheimer's type (n = 34), and Alzheimer's disease (AD) (n = 22). The results demonstrate significant correlations between UEF cognitive score and mini-mental state examination (MMSE), Mini-Cog, Category fluency, Benson complex figure copy, Trail making test, and Montreal cognitive assessment (MOCA) (r values between -0.2355 and -0.6037 and p < 0.0288).

DISCUSSION

UEF dual-task was associated with executive function, orientation, repetition, abstraction, verbal recall, attention and calculation, language and visual construction. Of the associated brain domains, UEF dual-task was most significantly associated with executive function, visual construction, and delayed recall. The results from this study convey potential for UEF dual-task as a safe and convenient cognitive impairment screening method.

Context expectation influences the gait pattern biomechanics

Beyond classical aspects related to locomotion (biomechanics), it has been hypothesized that walking pattern is influenced by a combination of distinct computations including online sensory/perceptual sampling and the processing of expectations (neuromechanics). Here, we aimed to explore the potential impact of contrasting scenarios ("risky and potentially dangerous" scenario; "safe and comfortable" scenario) on walking pattern in a group of healthy young adults. Firstly, and consistently with previous literature, we confirmed that the scenario influences gait pattern when it is recalled concurrently to participants' walking activity (motor interference). More intriguingly, our main result showed that participants' gait pattern is also influenced by the contextual scenario when it is evoked only before the start of walking activity (motor expectation). This condition was designed to test the impact of expectations (risky scenario vs. safe scenario) on gait pattern, and the stimulation that preceded walking activity served as prior. Noteworthy, we combined statistical and machine learning (Support-Vector Machine classifier) approaches to stratify distinct levels of analyses that explored the multi-facets architecture of walking. In a nutshell, our combined statistical and machine learning analyses converge in suggesting that walking before steps is not just a paradox.

USING THE SENSORY INTEGRATION TECHNIQUE FOR PEOPLE WITH AUTISM SPECTRUM DISORDERS DURING TRAINING AT THE CLIMBING SECTION

OBJECTIVE

Aim: To analyze the practical application of the sensory integration technique for individuals with autism spectrum disorder at a climbing section, and to investigate the impact of physical activity on improving their proprioceptive and vestibular systems.

PATIENTS AND METHODS

Materials and Methods: The method of included participant observation at the climbing classes with constant recording the behavior (desirable and undesirable) was used. The sensory screening (developed by J. Ayres) was applied for recording and determining the sensory systems of the people with ASD before the start of training and again after a month. The scale of Sensory Integration and Praxis Tests (SIPT) was used for assessing certain aspects of participants' sensory processing or perception according to the goals set during the climbing classes.

RESULTS

Results: The results of the research showed that the application of the sensory integration technique for individuals with ACD at a climbing section promoted the dynamics of changes in their sensory system during training considering the characteristics of their sensory system. The positive changes were observed in the way the people with ACD felt about their own bodies and their involvement in sports activities that in its turn made it possible to be active and develop their sensory system. It has been identified that while planning training for the people with ASD it is necessary to take into account sensory modulation (reading sensory signals) and apply exercises for stimulating sensory sensations that will improve the motor activity of persons with ASD, their social interaction, and safety, as well.

CONCLUSION

Conclusions: During training at the climbing section sensory information processing of the individuals with ASD have the impact on their body control, hand-eye coordination, and hand sensitivity during training. The improvement of sensory information processing in its turn enables people with ASD to master climbing.

Spatial orientation, postural control and the vestibular system in healthy elderly and Alzheimer's dementia

Background

While extensive research has been advancing our understanding of the spatial and postural decline in healthy elderly (HE) and Alzheimer's disease (AD), much less is known about how the vestibular system contributes to the spatial and postural processing in these two populations. This is especially relevant during turning movements in the dark, such as while walking in our garden or at home at night, where the vestibular signal becomes central. As the prevention of falls and disorientation are of serious concern for the medical service, more vestibular-driven knowledge is necessary to decrease the burden for HE and AD patients with vestibular disabilities.

Overview of the article

The review briefly presents the current "non-vestibular based" knowledge (i.e. knowledge based on research that does not mention the "vestibular system" as a contributor or does not investigate its effects) about spatial navigation and postural control during normal healthy ageing and AD pathology. Then, it concentrates on the critical sense of the vestibular system and explores the current expertise about the aspects of spatial orientation and postural control from a vestibular system point of view. The norm is set by first looking at how healthy elderly change with age with respect to their vestibular-guided navigation and balance, followed by the AD patients and the difficulties they experience in maintaining their balance or during navigation.

Conclusion

Vestibular spatial and vestibular postural deficits present a considerable disadvantage and are felt not only on a physical but also on a psychological level by all those affected. Still, there is a clear need for more (central) vestibular-driven spatial and postural knowledge in healthy and pathological ageing, which can better facilitate our understanding of the aetiology of these dysfunctions. A possible change can start with the more frequent implementation of the "vestibular system examination/rehabilitation/therapy" in the clinic, which can then lead to an improvement of future prognostication and disease outcome for the patients.

Tai Chi practice enables prefrontal cortex bilateral activation and gait performance prioritization during dual-task negotiating obstacle in older adults

BACKGROUND

With aging, the cognitive function of the prefrontal cortex (PFC) declined, postural control weakened, and fall risk increased. As a mind-body exercise, regular Tai Chi practice could improve postural control and effectively prevent falls; however, underlying brain mechanisms remained unclear, which were shed light on by analyzing the effect of Tai Chi on the PFC in older adults by means of functional near-infrared spectroscopy (fNIRS).

METHODS

36 healthy older adults without Tai Chi experience were divided randomly into Tai Chi group and Control group. The experiment was conducted four times per week for 16 weeks; 27 participants remained and completed the experiment. Negotiating obstacle task (NOT) and negotiating obstacle with cognitive task (NOCT) were performed pre- and post-intervention, and Brodmann area 10 (BA10) was detected using fNIRS for hemodynamic response. A three-dimensional motion capture system measured walking speed.

RESULTS

After intervention in the Tai Chi group under NOCT, the HbO2 concentration change value (ΔHbO2) in BA10 was significantly greater (right BA10: p = 0.002, left BA10: p = 0.001), walking speed was significantly faster (p = 0.040), and dual-task cost was significantly lower than pre-intervention (p = 0.047). ΔHbO2 in BA10 under NOCT was negatively correlated with dual-task cost (right BA10: r = -0.443, p = 0.021, left BA10: r = -0.448, p = 0.019). There were strong negative correlations between ΔHbO2 and ΔHbR under NOCT either pre-intervention (left PFC r = -0.841, p < 0.001; right PFC r = -0.795, p < 0.001) or post-intervention (left PFC r = -0.842, p < 0.001; right PFC r = -0.744, p < 0.001).

CONCLUSION

Tai Chi practice might increase the cognitive resources in older adults through the PFC bilateral activation to prioritize gait performance during negotiating obstacles under a dual-task condition.

Brain function complexity during dual-tasking is associated with cognitive impairment and age

BACKGROUND AND PURPOSE

Early diagnosis of cognitive impairment is important because symptoms can be delayed through therapies. Synaptic disconnections are the key characteristics of dementia, and through nonlinear complexity analysis of brain function, it is possible to identify long-range synaptic disconnections in the brain.

METHODS

We investigated the capability of a novel upper-extremity function (UEF) dual-task paradigm in the functional MRI (fMRI) setting, where the participant flexes and extends their arm while counting, to differentiate between cognitively normal (CN) and those with mild cognitive impairment (MCI). We used multiscale entropy (MSE) complexity analysis of the blood oxygen-level dependent time-series across neural networks and brain regions. Outside of the fMRI, we used the UEF dual-task test, while the elbow kinematics were measured using motion sensors, to record the motor function score.

RESULTS

Results showed 34% lower MSE values in MCI compared to CN (p<.04 for all regions and networks except cerebellum when counting down by one; effect size = 1.35±0.15) and a negative correlation between MSE values and age (average r2 of 0.30 for counting down by one and 0.36 for counting backward by three). Results also showed an improvement in the logistic regression model sensitivity by 14-24% in predicting the presence of MCI when brain function measure was added to the motor function score (kinematics data).

CONCLUSIONS

Current findings suggest that combining measures of neural network and motor function, in addition to neuropsychological testing, may provide an accurate tool for assessing early-stage cognitive impairment and age-related decline in cognition.

Asymmetric Influence of Dual-Task Interference on Anticipatory Postural Adjustments in One-Leg Stance

This study investigated the differences of anticipatory postural adjustments (APAs) in a one-leg stance (OLS) that appear according to lower-extremity dominance and dual-task interference. Thirteen young, healthy, male volunteers performed the OLS task under the following six conditions: (1) dominant leg (DL), single-task; (2) DL, dual-task, with a low level of cognitive load (DT1/2); (3) DL, dual-task, with a high level of cognitive load (DT + 1); (4) non-dominant leg (NDL), single-task; (5) NDL, DT1/2; and (6) NDL, DT + 1. In order to measure the subjects' APA, we used the medial-lateral displacement of their centers of pressure and gravity from the force plate and the time-series data of joint angular motions, recorded using a 3D motion analysis system. In the NDL under the dual-task condition, the onset of APA was delayed and the amplitude declined, which resulted in an increase in the duration of the APA period. The number of components identified by principal component analysis differed according to the dominant foot, and the change caused by cognitive load was found only in the NDL. As the cognitive load increased, the variance of the principal component decreased. These findings show that dual-task interference asymmetrically influences APA according to limb dominance, which reorganizes the coordination strategy of joints' angular motion.

Dementia and Risk Factors: Results from a Prospective, Population-Based Cohort Study

The incidence rate of dementia varies between studies. The influence of some sociodemographic factors is reasonably established, but less is known about the role of comorbidities, which are common in the elderly. The objectives of this study was to estimate the incidence of dementia in a population of Italian elders and evaluate the role of walking speed, comorbidity and ApoE-ɛ4 as well as various sociodemographic factors on the new onset of dementia. The InveCe.Ab study is a population-based longitudinal study in people born between 1935 and 1939 and resident in Abbiategrasso, Milan, Italy. After excluding subjects with a diagnosis of dementia and those without a definite diagnosis, 1103 individuals with a median follow-up time of 4.1 years were included in the analyses. The cumulative four-year incidence of dementia was 5.3%. Demographic factors such as old age, male, less educated, ApoE-ɛ4 carrier status and slower gait were risk factors for dementia onset in a cognitively healthy sub-cohort. Comorbidity did not influence the onset of dementia; instead, slow walking speed appears to be a strong predictor of dementia onset.

Two Immersive Virtual Reality Tasks for the Assessment of Spatial Orientation in Older Adults with and Without Cognitive Impairment: Concurrent Validity, Group Comparison, and Accuracy Results

OBJECTIVE

Spatial disorientation is common in Alzheimer's disease (AD), Mild Cognitive Impairment (MCI), and preclinical individuals with AD biomarkers. However, traditional neuropsychological tests lack ecological validity for the assessment of spatial orientation and to date, there is still no gold standard. The current study aimed to determine the validity and accuracy of two virtual reality tasks for the assessment of spatial orientation.

METHODS

We adapted two spatial orientation tasks to immersive virtual environments: a "survey to route" task in which participants had to transfer information from a map to their body position within a maze [Spatial Orientation in Immersive Virtual Environment Test (SOIVET) Maze], and an allocentric-type, route learning task, with well-established topographic landmarks (SOIVET Route). A total of 19 MCI patients and 29 cognitively healthy older adults aged 61-92 participated in this study. Regular neuropsychological assessments were used for correlation analysis and participant performances were compared between groups. Receiver Operating Characteristic (ROC) curve analysis was performed for accuracy.

RESULTS

The SOIVET Maze correlated with measures of visuoperception, mental rotation, and planning, and was not related to age, educational level, or technology use profile. The SOIVET Route immediate correlated with measures of mental rotation, memory, and visuoconstruction, and was influenced only by education. Both tasks significantly differentiated MCI and control groups, and demonstrated moderate accuracy for the MCI diagnosis.

CONCLUSION

Traditional neuropsychological assessment presents limitations and immersive environments allow for the reproduction of complex cognitive processes. The two immersive virtual reality tasks are valid tools for the assessment of spatial orientation and should be considered for cognitive assessments of older adults.

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.

A Dual-Task Paradigm Using the Oral Trail Making Test While Walking to Study Cognitive-Motor Interactions in Older Adults

Objective: With aging, gait becomes more dependent on executive functions, especially on switching abilities. Therefore, cognitive-motor dual-task (DT) paradigms should study the interferences between gait and switching tasks. This study aimed to test a DT paradigm based on a validated cognitive switching task to determine whether it could distinguish older-old adults (OO) from younger-old adults (YO).

Methods: Sixty-five healthy older participants divided into 29 younger-old (<70 years) and 36 older-old (≥70 years) age groups were evaluated in three single-task (ST) conditions as follows: a cognitive task including a processing speed component [Oral Trail Making Test part A (OTMT-A)], a cognitive task including a switching component [Oral Trail Making Test part B (OTMT-B)], and a gait evaluation at normal speed. They were also evaluated under two DT conditions, i.e., one associating gait with OTMT-A and the other associating gait with OTMT-B. Cognitive and gait performances were measured. The comparison of cognitive and gait performances between condition, logistic regression, and receiver operating characteristic (ROC) analyses were performed.

Results: The cognitive and gait performances were differently affected by the different conditions (i.e., ST, DT, OTMT-A, and OTMT-B). The OTMT-B produced higher interference on gait and cognitive performances. Moreover, a higher number of errors on the OTMT-B performed while walking was associated with the older-old age group.

Conclusion: Using validated cognitive flexibility tasks, this DT paradigm confirms the high interference between switching tasks and gait in older age. It is easily implemented, and its sensitivity to age may highlight its possible usefulness to detect cognitive or motor declines.

Cognitive, physical and disability trajectories in community-dwelling elderly people

Backgrounds and aims

Health trajectories in aging, rather than single time-point assessments, could be early indicators of the onset of conditions such as dementia. The aim of this study was to identify different aging trajectories and to investigate their influence on the cumulative incidence of dementia.

Methods

We evaluated data referring to 993 elders from the InveCe.Ab study cohort. All subjects were free from dementia at baseline and re-assessed on at least one other occasion thereafter. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), physical function using the Walking Speed Test (WST), and disability on the basis of the Activities of Daily Living (ADL) score. To describe the different courses of the three outcomes combined, the Group-Based Trajectory Model (GBTM) method was applied. We looked for differences in age, gender, education, ApoE-e4 carrier status and obesity, and then investigated the influence of the observed trajectories on the incidence of dementia.

Results

Three trajectories were identified: a “good” scenario was observed in 703 (70.2%) individuals, who showed substantially stable cognitive and physical function and no disability; an “intermediate” scenario in 248 subjects (25.5%), who recorded a longer walking time, lower MMSE score, and a one-point higher ADL score; and a “severe” scenario in 42 elders (4.3%), who recorded declines in all the outcomes. Female gender, obesity and low education were most represented in the “severe” group. ApoE-e4 carrier status showed no difference between groups. The estimated cumulative incidence of dementia was higher in the “severe” (37%) than in the “intermediate” (7%) and “good” (< 1%) scenarios.

Conclusions

Using simple measurements, we built different aging trajectories, and observed that the worst performers had the highest incidence of dementia. Better knowledge of trajectories of aging would be useful for preventive interventions aimed at promoting healthier aging.

Dual task walking costs in older adults with mild cognitive impairment: a systematic review and meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis (PROSPERO registration No CRD42020192121) is to review existing literature focusing on effects of different dual task paradigms on walking speed in older adults with and without Mild Cognitive Impairment.

METHODS

(1) Data Sources: PubMEd, Cumulative Index of Nursing and Allied Health, Cochrane library, and Web of Science. (2) Study Selection: The key terms searched included those associated with dual task, walking speed, executive function, older adults, and MCI. (3) Data Extraction: The search yielded 140 results with 20 studies meeting the inclusion criteria, which were rated by two independent reviewers using the Quality Assessment Tool. Descriptions of each study including the single and dual task protocol, outcome measure, and final outcomes were extracted. Meta-analysis was performed to evaluate the dual task effects on walking costs in older adults with and without MCI.

RESULTS

Meta-analysis revealed that there were significant differences in the dual task walking costs among older adults with or without MCI (p < .05). Pooled effect sizes of the serial subtraction (9.54; 95%CI, 3.93-15.15) and verbal fluency tasks (10.06; 95%CI, 6.26-15.65) showed that there are higher motor dual-task costs in older adults with MCI than age-matched controls. For quality assessment, all studies ranged from 12 to 16 in score, out of 18 (high quality).

CONCLUSIONS

In the studies included in this review, mental tracking tasks, consisting of serial subtraction and verbal fluency, were found to be the most sensitive in detecting MCI-related changes in older adults, and could serve an important role as a target measure for evaluating the efficacy of interventions aimed at improving cognitive and motor function in older adults.

The effectiveness of cognitive-motor training on reconstructing cognitive health components in older male adults, recovered from the COVID-19

Objective

The incidence of COVID-19 disease in the elderly can accelerate normal degenerative process of cognitive functions. Interactive cognitive-motor training (CMT) is an intervention that integrates cognitive and motor tasks to promote individuals’ physical and psychological health. The present study aimed to examine the effect of CMT on reconstructing cognitive health components in older men, who have recently recovered from COVID-19.

Materials and methods

This study is a quasi-experimental repeated measure (without control group). Participants were 42 elderly men (65–80 years) who recovered from the COVID-19 disease that individually participated in a 4-week CMT program twice a week. The cognitive health components of the participants were assessed by the General Health Questionnaire (GHQ-2) and the Mini-Mental State Examination (MMSE) at 3 stages before the beginning of the intervention (baseline assessment); 2 weeks after the intervention (short-term follow-up); and 3 months after the intervention (long-term follow-up).

Results

The results showed that the scores of depression, anxiety, physical symptoms, and social performance components and the overall GHQ score improved significantly in short-term follow-up (P < 0.05) and also in long-term follow-up compared to baseline assessment (P < 0.05). It was also found that attention and calculation, recall, lingual skill, and action performance components and the overall score of MMSE were also improved at three stages of assessments. Other components did not differ among stages.

Conclusions

This study adds to the research on the effectiveness of using CMT for reconstructing cognitive health components in older adults, recovered from the COVID-19, and supports CMT as a viable intervention practice.

Proof of Concept of Novel Visuo-Spatial-Motor Fall Prevention Training for Old People

Falls in the geriatric population are one of the most important causes of disabilities in this age group. Its consequences impose a great deal of economic burden on health and insurance systems. This study was conducted by a multidisciplinary team with the aim of evaluating the effect of visuo-spatial-motor training for the prevention of falls in older adults. The subjects consisted of 31 volunteers aged 60 to 92 years who were studied in three groups: (1) A group under standard physical training, (2) a group under visuo-spatial-motor interventions, and (3) a control group (without any intervention). The results of the study showed that visual-spatial motor exercises significantly reduced the risk of falls of the subjects.

Correlation Between Gait and Near-Infrared Brain Functional Connectivity Under Cognitive Tasks in Elderly Subjects With Mild Cognitive Impairment

Older adults with mild cognitive impairment (MCI) have a high risk of developing Alzheimer’s disease. Gait performance is a potential clinical marker for the progression of MCI into dementia. However, the relationship between gait and brain functional connectivity (FC) in older adults with MCI remains unclear. Forty-five subjects [MCI group, n = 23; healthy control (HC) group, n = 22] were recruited. Each subject performed a walking task (Task 01), counting backward–walking task (Task 02), naming animals–walking task (Task 03), and calculating–walking task (Task 04). The gait parameters and cerebral oxygenation signals from the left prefrontal cortex (LPFC), right prefrontal cortex (RPFC), left motor cortex (LMC), right motor cortex (RMC), left occipital leaf cortex (LOL), and right occipital leaf cortex (ROL) were obtained simultaneously. Wavelet phase coherence was calculated in two frequency intervals: low frequency (interval I, 0.052–0.145 Hz) and very low frequency (interval II, 0.021–0.052 Hz). Results showed that the FC of RPFC–RMC is significantly lower in interval I in Task 03 compared with that in Task 02 in the MCI group (p = 0.001). Also, the right relative symmetry index (IDpsR) is significantly lower in Task 03 compared with that in Task 02 (p = 0.000). The IDpsR is positively correlated with the FC of RPFC–RMC in interval I in the MCI group (R = 0.205, p = 0.041). The gait symmetry such as left relative symmetry index (IDpsL) and IDpsR is significantly lower in the dual-task (DT) situation compared with the single task in the two groups (p < 0.05). The results suggested that the IDpsR might reflect abnormal change in FC of RPFC–RMC in interval I in the MCI population during Task 03. The gait symmetry is affected by DTs in both groups. The findings of this study may have a pivotal role in the early monitoring and intervention of brain dysfunction among older adults with MCI.

Nonlinear analysis of the movement variability structure can detect aging-related differences among cognitively healthy individuals

Studying the dynamics of nonlinear systems can provide additional information about the variability structure of the system. Within the current study, we examined the application of regularity and local stability measures to capture motor function alterations due to dual-tasking using a previously validated upper-extremity function (UEF). We targeted young (ages 18 and 30 years) and older adults (65 years or older) with normal cognition based on clinical screening. UEF involved repetitive elbow flexion without counting (ST) and while counting backward by one (DT1) or three (DT3). We measured the regularity (measured by sample entropy (SE)), local stability (measured by the largest Lyapunov exponent (LyE)), as well as conventional peak-dependent variability measures (coefficient of variation of kinematics parameters) to capture motor dynamic alterations due to dual-tasking. Within both groups, only SE showed significant differences between all pairs of UEF condition comparisons, even ST vs DT1 (p = 0.007, effect size = 0.507), for which no peak-dependent parameter showed significant difference. Among all measures, the only parameter that showed a significant difference between young and older adults was LyE (p < 0.001, effect size = 0.453). Current findings highlight the potential of nonlinear analysis to detect aging-related alterations among cognitively healthy participants.

The Effects of Exergame on Postural Control in Individuals with Ataxia: a Rater-Blinded, Randomized Controlled, Cross-over Study

Exergame trainings might have therapeutic value in ataxic patients. The aim of this study was to investigate the effect of exergame training with an exercise program on postural control by comparing it with traditional balance and coordination exercise program. Nineteen patients were randomly allocated to two groups. In the first group, exergame training and an exercise program (EEP) were applied together for the first 8 weeks; after 10 weeks washout, a conventional exercise program (CEP) was applied for the second 8 weeks. In the second group, the CEP was applied first followed by the EEP. Outcome measures were Limits of Stability test (LoS), International Classification Ataxia Ratio Scale (ICARS), Berg Balance Scale (BBS), and Timed-Up and Go test with a cognitive task (TUG-C), Reactive postural control and sensory orientation subscales of the Mini-BESTest. Seventeen patients (mean age ± SD, 32.53 ± 11.07 years) completed the study. ICARS, BBS scores improved only after EEP (p < 0.05). While there was no change in the RT and MVL parameters of the LoS test after EEP, the MXE, EPE, and DCL parameters improved significantly (p < 0.05). The MXE and MVL parameters of LoS improved after CEP (p < 0.05). There were no significant improvements in the Mini-BESTest's reactive postural control and sensory orientation subscale scores after both EEP and CEP (p > 0.05). The results of the present study demonstrated that exergame training can be used as a complementary training option in physiotherapy to improve postural control in patients with ataxia. ClinicalTrial.gov Identifier: NCT03607058.

The Effect of Whole Body Vibration on Postural Control of Ataxic Patients: a Randomized Controlled Cross-Over Study

Whole body vibration (WBV) applications have been used in recent years to increase muscle strength, power, and postural control in healthy and various disease populations. This study aims to investigate the effects of WBV on postural control in patients with ataxia. Twenty-four patients were randomly allocated to two groups. In the first group, whole body vibration and exercise therapy (WBV + E) were applied together for the first 8 weeks; after 1 week washout, only exercise program (OE) was applied for the second 8 weeks. In the second group, the OE program was applied first followed by the WBV + E program. Outcome measures were Sensory Organization Test (SOT), Adaptation Test (ADT), Limits of Stability Test (LOS), International Classification Ataxia Ratio Scale (ICARS), Berg Balance Scale (BBS), and Timed Up and Go Test with cognitive task (TUG-C). Twenty patients (mean age ± SD, 34.00 ± 9.16 years) completed the study. The scores of SOT, ICARS, and BBS improved significantly after both OE and WBV + E program (p < 0.05). Improvements in the WBV + E program were higher (p < 0.05). The scores of ADT, TUG-C, and three parameters of LOS improved significantly after WBV + E (p < 0.05), while there was no significant change after OE (p > 0.05). This study demonstrated that exercise programs supported by WBV can play an important role in the improvement of all components of postural control in patients with ataxia. ClinicalTrial.gov Identifier: NCT02977377.

Spatial-Temporal Parameters of Gait Associated With Alzheimer Disease: A Longitudinal Analysis

Alzheimer's disease (AD) is one of the biggest social and medical concerns in the aging world. A dual task of walking and talking is a particularly practical means to assess AD considering the cognitive and behavioral changes that characterize the disease. The purpose of the study was to assess the effect of the dual task of walking and talking on people with early stage AD under differing cognitive load levels of talking. Participants (9 women and 5 men, mean age (years) = 78.03, standard deviation [SD] = 12.06) with mild or moderate AD (mean Dementia Rating Scale 2 score = 88.14, SD = 7.07) completed 12 monthly walking sessions under no, low, or high cognitive load. They also completed the low and high cognitive load tasks while seated. Linear mixed-effects modeling revealed that values in the Functional Ambulation Profile, stride length, and velocity decreased as tasks became more complex and double support time increased at the same rate. The walking and seated conditions comparison indicated that participants' performance on both low and high cognitive tasks was poor when they were walking rather than seated. The results show that people with early stage AD exhibited gait impairments that increased over time and when completing tasks with greater cognitive load.

Changes in attentional resources during the acquisition of laparoscopic surgical skills

Background

Increasing familiarity and practice might free up mental resources during laparoscopic surgical skills training. The aim of the study was to track changes in mental resource allocation during acquisition of laparoscopic surgical skills.

Methods

Medical students with no previous experience in laparoscopic surgery took part in a 5-week laparoscopic training curriculum. At the beginning and end of the training period, one of the training tasks was combined with a secondary auditory detection task that required pressing a foot switch for defined target tones, creating a dual-task situation. During execution of the two concurrent tasks, continuous electroencephalographic measurements were made, with special attention to the P300 component, an index of mental resources. Accuracy and reaction times of the secondary task were determined.

Results

All 14 participants successfully completed the training curriculum. Target times for successful completion of individual tasks decreased significantly during training sessions (P  <0.001 for all tasks). Comparing results before and after training showed a significant decrease in event-related brain potential amplitude at the parietal electrode cluster (P300 component, W = 67, P = 0.026), but there were no differences in accuracy (percentage correct responses: W = 48, P = 0.518) or reaction times (W = 42, P = 0.850) in the auditory detection task.

Conclusion

The P300 decrease in the secondary task over training demonstrated a shift of mental resources to the primary task: the surgical exercise. This indicates that, with more practice, mental resources are freed up for additional tasks.

Percentiles and Reference Values for Accelerometric Gait Assessment in Women Aged 50-80 Years

Background: The identification of factors that alter postural stability is fundamental in the design of interventions to maintain independence and mobility. This is especially important for women because of their longer life expectancy and higher incidence of falls than in men. We constructed the percentile box charts and determined the values of reference for the accelerometric assessment of the gait in women. Methods: We used a cross-sectional study with 1096 healthy adult women, who were asked to walk a distance of 20 m three times. Results: In all of the variables, a reduction in the magnitude of accelerations was detected as the age of the group advanced. The box charts show the amplitude of the interquartile ranges, which increases as the age of the participants advances. In addition, the interquartile ranges were greater in the variables that refer to the maximum values of the accelerations. Conclusions: The values obtained can be used to assess changes in gait due to aging, trauma and orthopaedic alterations that may alter postural stability and neurodegenerative processes that increase the risk of falling.

Cognitive and physical markers of prodromal dementia: A 12-year-long population study

INTRODUCTION

The aim is to test whether adding a simple physical test such as walking speed (WS) to the neuropsychological assessment increases the predictive ability to detect dementia.

METHODS

The 2546 dementia-free people from the SNAC-K study were grouped into four profiles: (1) healthy profile; (2) isolated cognitive impairment, no dementia (CIND, scoring 1.5 standard deviation below age-specific means on ≥1 cognitive domains); (3) isolated slow WS (<0.8 m/s); (4) CIND+ slow WS. The hazard of dementia (Cox regression), the positive and negative predictive values (PPV, NPV), and the area under the curve (AUC) were estimated.

RESULTS

Participants with CIND +slow WS demonstrated the highest hazard of dementia (3.4; 95% confidence interval [CI]: 2.5-4.8). The AUC increased from 0.69 for isolated CIND to 0.83 for CIND+ slow WS. Such an increase was due to the improvement of the PPV, the NPV remaining optimal.

DISCUSSION

Adding WS to the cognitive assessment dramatically increases the diagnostic accuracy of prodromal dementia.

Dual-task gait speed assessments with an electronic walkway and a stopwatch in older adults. A reliability study

BACKGROUND/OBJECTIVES

Slow gait speed prospectively predicts elevated risk of adverse events such as falls, morbidity, and mortality. Additionally, gait speed under a cognitively demanding challenge (dual-task gait) predicts further cognitive decline and dementia incidence. This evidence has been mostly collected using electronic walkways; however, not all clinical set ups have an electronic walkway and comparability with simple manual dual-gait speed testing, like a stopwatch, has not yet been examined. Our main objective was to assess concurrent-validity and reliability of gait speed assessments during dual-tasking using a stopwatch and electronic walkway in older adults with mild and subjective cognitive impairment (MCI and SCI).

DESIGN

Cross-sectional, reliability study.

SETTING

Clinic based laboratory at an academic hospital in London, ON, Canada.

PARTICIPANTS

237 walk tests from 34 community-dwelling participants (mean age 71.84 SD 5.38; 21 female - 62%, 13 male - 38%) with SCI and MCI. were included from the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) study.

INTERVENTION

Each participant performed seven walk tests: three single gait walks at their normal pace, three dual-task walks (walking and counting backwards by one, by sevens, and naming animals), and one fast walk.

MEASUREMENTS

Gait speed (cm/s) for each walk was measured simultaneously with an electronic walkway (Zeno Mat®) and a handheld stopwatch (Ultrak chronometer®). Dual-task cost (DTC) was calculated for the three individual dual-task walks as [((single gait speed - dual-task gait speed) / single gait speed) ∗ 100]. Level of agreement between the two measurement methods was analyzed using Pearson correlations, paired t-tests, and Bland-Altman plots.

RESULTS

Gait speed was consistently lower when measured with the stopwatch than with the electronic walkway (mean speed difference: 10.6 cm/s ± 5.1, p < 0.001). Calculating DTC, however, yielded very similar results with both methods (mean DTC difference: 0.19 ± 1.18, p = 0.872). The higher the DTC, the closer the measurement between methods.

CONCLUSION

Assessing and calculating DTC with a stopwatch is simple, accessible and reliable. Its validity and reliability were high in this clinical sample of community older adults with SCI and MCI.

Interactions Between Different Age-Related Factors Affecting Balance Control in Walking

Maintaining balance during walking is a continuous sensorimotor control problem. Throughout the movement, the central nervous system has to collect sensory data about the current state of the body in space, use this information to detect possible threats to balance and adapt the movement pattern to ensure stability. Failure of this sensorimotor loop can lead to dire consequences in the form of falls, injury and death. Such failures tend to become more prevalent as people get older. While research has established a number of factors associated with higher risk of falls, we know relatively little about age-related changes of the underlying sensorimotor control loop and how such changes are related to empirically established risk factors. This paper approaches the problem of age-related fall risk from a neural control perspective. We begin by summarizing recent empirical findings about the neural control laws mapping sensory input to motor output for balance control during walking. These findings were established in young, neurotypical study populations and establish a baseline of sensorimotor control of balance. We then review correlates for deteriorating balance control in older adults, of muscle weakness, slow walking, cognitive decline, and increased visual dependency. While empirical associations between these factors and fall risk have been established reasonably well, we know relatively little about the underlying causal relationships. Establishing such causal relationships is hard, because the different factors all co-vary with age and are difficult to isolate empirically. One option to analyze the role of an individual factor for balance control is to use computational models of walking comprising all levels of the sensorimotor control loop. We introduce one such model that generates walking movement patterns from a short list of spinal reflex modules with limited supraspinal modulation for balance. We show how this model can be used to simulate empirical studies, and how comparison between the model and empirical results can indicate gaps in our current understanding of balance control. We also show how different aspects of aging can be added to this model to study their effect on balance control in isolation.

Dual-task tests discriminate between dementia, mild cognitive impairment, subjective cognitive impairment, and healthy controls - a cross-sectional cohort study

Background

Discrimination between early-stage dementia and other cognitive impairment diagnoses is central to enable appropriate interventions. Previous studies indicate that dual-task testing may be useful in such differentiation. The objective of this study was to investigate whether dual-task test outcomes discriminate between groups of individuals with dementia disorder, mild cognitive impairment, subjective cognitive impairment, and healthy controls.

Methods

A total of 464 individuals (mean age 71 years, 47% women) were included in the study, of which 298 were patients undergoing memory assessment and 166 were cognitively healthy controls. Patients were grouped according to the diagnosis received: dementia disorder, mild cognitive impairment, or subjective cognitive impairment. Data collection included participants’ demographic characteristics. The patients’ cognitive test results and diagnoses were collected from their medical records. Healthy controls underwent the same cognitive tests as the patients. The mobility test Timed Up-and-Go (TUG single-task) and two dual-task tests including TUG (TUGdt) were carried out: TUGdt naming animals and TUGdt months backwards. The outcomes registered were: time scores for TUG single-task and both TUGdt tests, TUGdt costs (relative time difference between TUG single-task and TUGdt), number of different animals named, number of months recited in correct order, number of animals per 10 s, and number of months per 10 s. Logistic regression models examined associations between TUG outcomes pairwise between groups.

Results

The TUGdt outcomes “animals/10 s” and “months/10 s” discriminated significantly (p < 0.001) between individuals with an early-stage dementia diagnosis, mild cognitive impairment, subjective cognitive impairment, and healthy controls. The TUGdt outcome “animals/10 s” showed an odds ratio of 3.3 (95% confidence interval 2.0–5.4) for the groups dementia disorders vs. mild cognitive impairment. TUGdt cost outcomes, however, did not discriminate between any of the groups.

Conclusions

The novel TUGdt outcomes “words per time unit”, i.e. “animals/10 s” and “months/10 s”, demonstrate high levels of discrimination between all investigated groups. Thus, the TUGdt tests in the current study could be useful as complementary tools in diagnostic assessments. Future studies will be focused on the predictive value of TUGdt outcomes concerning dementia risk for individuals with mild cognitive impairment or subjective cognitive impairment.

Minimal Detectable Change in Dual-Task Cost for Older Adults With and Without Cognitive Impairment

BACKGROUND AND PURPOSE

Dual-task (DT) training has become a common intervention for older adults with balance and mobility limitations. Minimal detectable change (MDC) of an outcome measure is used to distinguish true change from measurement error. Few studies reporting on reliability of DT outcomes have reported MDCs. In addition, there has been limited methodological DT research on persons with cognitive impairment (CI), who have relatively more difficulty with DTs than persons without CI. The purpose of this study was to describe test-retest reliability and MDC for dual-task cost (DTC) in older adults with and without CI and for DTs of varying difficulty.

METHODS

Fifty participants 65 years and older attended 2 test sessions within 7 to 19 days. Participants were in a high cognitive group (n = 27) with a Montreal Cognitive Assessment (MoCA) score of 26 or more, or a low cognitive group (n = 23) with a MoCA score of less than 26. During both sessions, we used a pressure-sensing walkway to collect gait data from participants. We calculated motor DTC (the percent decline in motor performance under DT relative to single-task conditions) for 4 DTs: the Timed Up and Go (TUG) while counting forward by ones (TUG1) and counting backward by threes (TUG3); and self-selected walking speed (SSWS) with the same secondary tasks (SSWS1 and SSWS3). Intraclass correlation coefficients (ICCs) and MDCs were calculated for DTC for the time to complete the TUG and spatiotemporal gait variables during SSWS. A 3-way analysis of variance was used to compare differences in mean DTC between groups, tasks, and sessions.

RESULTS AND DISCUSSION

ICCs varied across groups and tasks, ranging from 0.02 to 0.76. MDCs were larger for individuals with low cognition and for DTs involving counting backward by threes. For example, the largest MDC was 503.1% for stride width during SSWS3 for individuals with low cognition, and the smallest MDC was 5.6% for cadence during SSWS1 for individuals with high cognition. Individuals with low cognition demonstrated greater DTC than individuals with high cognition. SSWS3 and TUG3 resulted in greater DTC than SSWS1 and TUG1. There were no differences in DTC between sessions for any variable.

CONCLUSIONS

Our study provides MDCs for DTC that physical therapists may use to assess change in older adults who engage in DT training. Persons with low cognition who are receiving DT training must exhibit greater change in DTC before one can be confident the change is real. Also, greater change must be observed for more challenging DTs. Thus, cognitive level and task difficulty should be considered when measuring change with DT training.

Sex differences in age-related impairments vary across cognitive and physical assessments in rats

Inclusion of female subjects in preclinical biomedical research is imperative for understanding mechanisms of age-related cognitive decline, as more than half of individuals older than 65 are female. In rodents, however, few behavioral and physical assessments have been conducted in both sexes within the same study. The current article documents data obtained from young and aged rats of both sexes that performed a battery of cognitive and physical assessments to examine for potential interactions between sex and age. Physical performance was measured with a rotarod test of motor coordination, assessment of maximum grip strength, and swim speed. While females outperformed males in rotarod and grip strength, there was also an age-dependent decline in physical performance in both sexes. Cognitive assessments included the Morris watermaze test of hippocampal dependent spatial memory and a biconditional association task with a working memory (WM) component, both of which were not significantly different across sex. Notably, a cognitive dual task that simultaneously tests working memory (WM) and biconditional association task (BAT) acquisition has previously been shown to be more sensitive to age-related cognitive decline than the watermaze in male rats, which is replicated here in both female and male rats. Furthermore, young and aged females (<27 months) spent a similar percent of time in each estrus cycle phase and phase did not influence WM/BAT performance. Future studies utilizing similar behavioral paradigms to examine the neurobiology of cognitive aging should be representative of the human population they intend to model through the inclusion of female subjects. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Aβ42/Aβ40 and Aβ42/Aβ38 Ratios Are Associated with Measures of Gait Variability and Activities of Daily Living in Mild Alzheimer's Disease: A Pilot Study

Gait disturbances are some of the earliest changes in dementia and their monitoring presents an opportunity for early diagnosis. The exact relationship between gait and well-established biomarkers of Alzheimer’s disease (AD) remains to be clarified. In this study we compared gait-related measures with cerebrospinal fluid (CSF) markers of AD pathology. We recruited seventeen participants with mild AD in a multi-site study and performed gait assessment as well as lumbar punctures to obtain CSF. CSF Aβ₄₂/Aβ₄₀ and Aβ₄₂/Aβ₃₈ correlated positively with measures of variability (step time and step length) in the clinic-based assessments. This was driven by a negative relationship between gait variability and Aβ₄₀ and Aβ₃₈ but not Aβ₄₂.The amyloid ratios and gait variability measures were also associated with more severe functional impairment. We interpret these data as an indication that increasing amyloid production (i.e., increasing Aβ₄₀ and Aβ₃₈) is associated with diminishing cognitive-motor control of gait. These preliminary results suggest that the two amyloid ratios may be a marker of the earliest disturbances in the interplay between cognitive and motor control which characterize dementia.

Screening older adults for amnestic mild cognitive impairment and early-stage Alzheimer's disease using upper-extremity dual-tasking

The purpose of the current study was to develop an objective tool based on dual-task performance for screening early-stage Alzheimer’s disease (AD) and mild cognitive impairment (MCI of the Alzheimer’s type). Dual-task involved a simultaneous execution of a sensor-based upper-extremity function (UEF) motor task (normal or rapid speed) and a cognitive task of counting numbers backward (by ones or threes). Motor function speed and variability were recorded and compared between cognitive groups using ANOVAs, adjusted for age, gender, and body mass index. Cognitive indexes were developed using multivariable ordinal logistic models to predict the cognitive status using UEF parameters. Ninety-one participants were recruited; 35 cognitive normal (CN, age = 83.8 ± 6.9), 34 MCI (age = 83.9 ± 6.6), and 22 AD (age = 84.1 ± 6.1). Flexion number and sensor-based motion variability parameters, within the normal pace elbow flexion, showed significant between-group differences (maximum effect size of 1.10 for CN versus MCI and 1.39 for CN versus AD, p < 0.0001). Using these parameters, the cognitive status (both MCI and AD) was predicted with a receiver operating characteristic area under curve of 0.83 (sensitivity = 0.82 and specificity = 0.72). Findings suggest that measures of motor function speed and accuracy within a more practical upper-extremity test (instead of walking) may provide enough complexity for cognitive impairment assessment.

Measuring gait speed to better identify prodromal dementia

Slow gait speed has been shown to predict incident dementia and cognitive decline in older individuals. We aimed to summarize the evidence concerning the association of slow gait speed with cognitive decline and dementia, and discuss the possible shared pathways leading to cognitive and motor impairments, under the unifying hypothesis that body and mind are intimately connected. This is a scoping review supported by a systematic search of the literature, performed on PubMed and Web of Science. Longitudinal studies providing information on the role of gait speed in the prediction of cognitive decline and dementia in cognitively intact people and in those with initial cognitive impairment were eligible. Of 39 studies selected, including overall 57,456 participants, 33 reported a significant association between gait speed and cognitive outcomes, including dementia. Neurodegenerative pathology and cerebrovascular burden may damage cerebral areas involved in both cognitive functions and motor control. At the same time, systemic conditions, characterized by higher cardiorespiratory, and metabolic and inflammatory burden, can affect a number of organs and systems involved in motor functions, including the brain, having ultimately an impact on cognition. The interplay of body and mind seems relevant during the development of cognitive decline and dementia. The measurement of gait speed may improve the detection of prodromal dementia and cognitive impairment in individuals with and without initial cognitive deficits. The potential applicability of such a measure in both clinical and research settings points at the importance of expanding our knowledge about the common underlying mechanisms of cognitive and motor decline.

High Postural Sway Is an Independent Risk Factor for Osteoporotic Fractures but Not for Mortality in Elderly Women

The aim of this prospective cohort study was to investigate the independent effect of postural sway on overall fracture and osteoporotic fracture risk after controlling for other established fracture risk factors. As a secondary outcome, mortality was also investigated. The study sample is a stratified random sample of 1568 women born between 1932 and 1941, residing in Kuopio province, eastern Finland. Fracture data were obtained through study questionnaires and verified through hospital records. Mortality data were verified through the National Registry. Using static posturography, postural sway was recorded for 1568 women at the fifth year of follow-up in 1994 through 1997. Mediolateral (ML), anteroposterior (AP), and total sway parameters were used for analysis. Mean follow-up time for any fractures, osteoporotic fractures, and mortality was 10.6, 11.4, and 17.5 years, respectively. After adjustment, subjects in the highest quartile of ML sway (HR, 2.0; 95% CI, 1.5 to 2.8) and total sway (HR, 1.6; 95% CI, 1.2 to 2.2) had a higher risk for any fracture. Osteoporotic fracture risk was also higher in the fourth quartile of ML sway (HR, 1.9; 95% CI, 1.1 to 3.0) and total sway (HR, 1.7; 95% CI, 1.0 to 2.8). The models were adjusted for fracture risk assessment tool risk factors and leg-extension strength. Further, women having both lowest bone density and highest postural sway were at 4.9 (95% CI, 2.6 to 9.5) times higher risk of overall fracture and 11.8 (95% CI, 2.7 to 51.3) times higher risk for osteoporotic fracture in comparison with subjects having highest bone density and lowest postural sway. The association between postural sway and mortality was not significant after adjustment. In conclusion, high postural sway is an independent risk factor for any fractures as well as for osteoporotic fractures. A combination of low bone density and high postural sway poses even higher fracture risk than either factor alone. Postural sway does not predict mortality independently. © 2019 American Society for Bone and Mineral Research.

The attentional cost of movement in multiple sclerosis

Individuals living with multiple sclerosis frequently have impairments in mobility. These impairments are more pronounced when they engage in a cognitively demanding mobility tasks (i.e., walking and talking, obstacle clearance, etc). Based in part on the attentional capacity model of movement, these impairments are suggested to result from greater attentional demands. Yet, this model has not been directly tested in neurological populations. The objective of the study was to determine whether individuals with multiple sclerosis have greater attentional cost of movement across a range of tasks. This study tested probe reaction times of 20 individuals with multiple sclerosis and 26 healthy controls in five different movement tasks. The tasks were specifically chosen to challenge the perceptual-motor system based on variations in static and dynamic balance requirements. Participants were asked to verbally respond as quickly as possible to randomly presented audio probes during motor performance. Task order was randomized, and average probe reaction time was calculated for each task. The results showed tasks requiring dynamic stability had greater probe reaction times in both healthy controls and individuals with multiple sclerosis. Furthermore, individuals with multiple sclerosis had longer probe reaction times across all tasks compared to healthy controls. Yet, there was no relationship between probe reaction times and performance during a complex walking scenario. The results indicate the attentional capacity model may be inadequate to explain cognitive-motor interaction in people with multiple sclerosis. Future studies should address the theoretical framework of cognitive-motor interaction, which may influence the design of interventions aimed at improving performance in individuals with MS.

The association between cognition and dual-tasking among older adults: the effect of motor function type and cognition task difficulty

Background

Dual-task actions challenge cognitive processing. The usefulness of objective methods based on dual-task actions to identify the cognitive status of older adults has been previously demonstrated. However, the properties of select motor and cognitive tasks are still debatable. We investigated the effect of cognitive task difficulty and motor task type (walking versus an upper-extremity function [UEF]) in identifying cognitive impairment in older adults.

Methods

Older adults (≥65 years) were recruited, and cognitive ability was measured using the Montreal Cognitive Assessment (MoCA). Participants performed repetitive elbow flexion under three conditions: 1) at maximum pace alone (Single-task); and 2) while counting backward by ones (Dual-task 1); and 3) threes (Dual-task 2). Similar single- and dual-task gait were performed at normal speed. Three-dimensional kinematics were measured for both motor functions using wearable sensors.

Results

One-hundred older adults participated in this study. Based on MoCA score <20, 21 (21%) of the participants were considered cognitively impaired (mean age =86±10 and 85±5 for cognitively impaired and intact participants, respectively). Within ANOVA models adjusted with demographic information, UEF dual-task parameters, including speed and range-of-motion variability were significantly higher by 52% on average, among cognitively impaired participant (p<0.01). Logistic models with these UEF parameters plus age predicted cognitive status with sensitivity, specificity, and area under curve (AUC) of 71%, 81% and 0.77 for Dual-task 1. The corresponding values for UEF Dual-task 2 were 91%, 73% and 0.81, respectively. ANOVA results were non-significant for gait parameters within both dual-task conditions (p>0.26).

Conclusion

This study demonstrated that counting backward by threes within a UEF dual-task experiment was a pertinent and challenging enough task to detect cognitive impairment in older adults. Additionally, UEF was superior to gait as the motor task component of the dual-task. The UEF dual-task could be applied as a quick memory screen in a clinical setting.

The Diagnostic and Prognostic Value of a Dual-Tasking Paradigm in a Memory Clinic

BACKGROUND

Daily living requires the ability to perform dual-tasking. As cognitive skills decrease in dementia, performing a cognitive and motor task simultaneously become increasingly challenging and subtle gait abnormalities may even be present in pre-dementia stages. Therefore, a dual-tasking paradigm, such as the Timed Up and Go-Dual Task (TUG-DT), may be useful in the diagnostic assessment of mild cognitive impairment (MCI).

OBJECTIVE

To investigate the diagnostic and prognostic ability of a dual-tasking paradigm in patients with MCI or mild Alzheimer's disease (AD) and to evaluate the association between the dual-tasking paradigm and cerebrospinal fluid (CSF) AD biomarkers.

METHODS

The study is a prospective cohort study conducted in a clinical setting in two memory clinics. Eighty-six patients were included (28 MCI, 17 AD, 41 healthy controls (HC)). The ability to perform dual-tasking was evaluated by the TUG-DT. Patients underwent a standardized diagnostic assessment and were evaluated to determine progression yearly.

RESULTS

ROC curve analysis illustrated a high discriminative ability of the dual-tasking paradigm in separating MCI patients from HC (AUC: 0.78, AUC: 0.82) and a moderate discriminative ability in separating MCI from AD (AUC: 0.73, AUC: 0.55). Performance discriminated clearly between all groups (p < 0.01). Logistic regression analyses revealed a low prognostic value of the dual-tasking paradigm for progression and rate of cognitive decline. A moderately strong correlation between the dual-tasking paradigm and CSF AD biomarkers was observed.

CONCLUSION

In our study, we found that patients with MCI and mild AD have increasing difficulties in dual-tasking compared to healthy elderly. Hence, the dual-tasking paradigm may be a potential complement in the diagnostic assessment in a typical clinical setting.

Cognitive-motor interference during goal-directed upper-limb movements

Research and clinical practice have focused on effects of a cognitive dual‐task on highly automated motor tasks such as walking or maintaining balance. Despite potential importance for daily life performance, there are only a few small studies on dual‐task effects on upper‐limb motor control. We therefore developed a protocol for assessing cognitive‐motor interference (CMI) during upper‐limb motor control and used it to evaluate dual‐task effects in 57 healthy individuals and two highly prevalent neurological disorders associated with deficits of cognitive and motor processing (57 patients with Parkinson's disease [PD], 57 stroke patients). Performance was evaluated in cognitive and motor domains under single‐ and dual‐task conditions. Patterns of CMI were explored to evaluate overall attentional capacity and attention allocation. As expected, patients with neurological deficits showed different patterns of CMI compared to healthy individuals, depending on diagnosis (PD or stroke) and severity of cognitive and/or motor symptoms. Healthy individuals experienced CMI especially under challenging conditions of the motor task. CMI was greater in PD patients, presumably due to insufficient attentional capacity in relation to increased cognitive involvement in motor control. Although no general increase of CMI was observed in stroke patients, correlation analyses suggested that especially patients with severe motor dysfunction experienced CMI. Clinical ratings of cognitive and motor function were weakly associated with CMI, suggesting that CMI reflects a different construct than these unidimensional clinical tests. It remains to be investigated whether CMI is an indicator of difficulties with day‐to‐day activities.

Lower cerebral vasoreactivity as a predictor of gait speed decline in type 2 diabetes mellitus

Gait speed is an indicator of overall functional health and is correlated with survival in older adults. We prospectively evaluated the long-term association between cerebral vasoreactivity and gait speed during normal walking (NW) and dual-task walking (DTW) in older adults with and without type 2 diabetes mellitus (T2DM). 40 participants (aged 67.3 ± 8.8 years, 20 with T2DM) completed a 2-year prospective study consisting of MRI, blood sampling, and gait assessments. The whole brain vasoreactivity was quantified using continuous arterial spin labeling MRI. Gait speed during DTW was assessed by subtracting serial sevens. Dual-task cost was calculated as the percent change in gait speed from NW to DTW. In the entire cohort, higher glycemic profiles were associated with a slower gait speed. In the diabetic group, lower vasoreactivity was associated with a slower gait speed during NW ([Formula: see text] = 0.30, p = 0.019) and DTW ([Formula: see text] = 0.35, p = 0.01) and a higher dual-task cost ([Formula: see text] = 0.69, p = 0.009) at 2-year follow-up. The participants with T2DM and lower cerebral vasoreactivity had a greater decrease in gait speed during NW and DTW after the 2-year follow-up ([Formula: see text] = 0.17, p = 0.04 and [Formula: see text] = 0.28, p = 0.03, respectively). Longer diabetes duration was associated with a higher dual-task cost ([Formula: see text] = 0.19, p = 0.04) and a greater decrease in gait speed during NW ([Formula: see text] = 0.17, p = 0.02). These findings indicate that in older adults with type 2 diabetes, gait performance is highly dependent on the integrity of cerebrovascular regulation.

Effects of dual tasking and methylphenidate on gait in children with attention deficit hyperactivity disorder

Effects of dual tasking on motor processes such as gait have been mainly investigated with healthy adults and clinical older samples whereas studies with clinical samples of children with attention deficit hyperactivity disorder (ADHD) are rare. Similarly, even though methylphenidate (MPH) is the most often prescribed medication for children with ADHD, the influence of MPH on children's gait under single-task and dual-task situations remains poorly understood. In the current study, children diagnosed with ADHD (n = 26) came twice to the laboratory, once without and once with MPH medication. They were asked to walk over an electronic walkway without a concurrent task (motor single task) and while solving different cognitive tasks (motor-cognitive dual task). Gait variability and cognitive performance were measured. Children's performance was compared to an age- and sex-matched control sample of typically developing children (n = 26) who were also tested twice. Results indicated considerable effects of dual tasking on children's gait irrespective of group (ADHD vs. controls), with children diagnosed with ADHD showing more pronounced gait alterations in dual-task situations as compared to controls. Furthermore, MPH medication in children with ADHD enabled them to substantially decrease their stride time variability to a level that was comparable to the level of typically developing children. Overall, our findings support the notion that higher cognitive processes such as attention and executive functions influence gait and that MPH can positively affect cognitive and motor processes such as gait.

Dual-Task Gait and Alzheimer's Disease Genetic Risk in Cognitively Normal Adults: A Pilot Study

BACKGROUND

Dual-task paradigms, in which an individual performs tasks separately and then concurrently, often demonstrate that people with neurodegenerative disorders experience more dual-task interference, defined as worse performance in the dual-task condition compared to the single-task condition.

OBJECTIVE

To examine how gait-cognition dual-task performance differs between cognitively normal older adults with and without an APOE ɛ4 allele.

METHODS

Twenty-nine individuals ages 60 to 72 with normal cognition completed a dual-task protocol in which walking and cognitive tasks (executive function, memory) were performed separately and concurrently. Fourteen participants carried APOE ɛ4 alleles (ɛ3/ɛ4 or ɛ2/ɛ4); fifteen had APOE genotypes (ɛ2/ɛ2, ɛ2/ɛ3, or ɛ3/ɛ3) associated with lower risk of Alzheimer's disease (AD).

RESULTS

The two risk groups did not differ by age, sex, race, education, or gait or cognitive measures under single-task conditions. Compared to low risk participants, APOE ɛ4 carriers tended to exhibit greater dual-task interference. Both the memory and executive function tasks resulted in dual-task interference on gait, but effect sizes for a group difference were larger when the cognitive task was executive function. In the dual-task protocol that combined walking and the executive function task, effect sizes for group difference in gait interference were larger (0.62- 0.70) than for cognitive interference (0.45- 0.47).

DISCUSSION

Dual-task paradigms may reveal subtle changes in brain function in asymptomatic individuals at heightened risk of AD.

Guidelines for Gait Assessments in the Canadian Consortium on Neurodegeneration in Aging (CCNA)

Background

Motor and cognitive impairments are common among older adults and often co-exist, increasing their risk of dementia, falls, and fractures. Gait performance is an accepted indicator of global health and it has been proposed as a valid motor marker to detect older adults at risk of developing mobility and cognitive declines including future falls and incident dementia. Our goal was to provide a gait assessment protocol to be used for clinical and research purposes.

Methods

Based on a consensus that identified common evaluations to assess motor–cognitive interactions in community-dwelling older individuals, a protocol on how to evaluate gait in older adults for the Canadian Consortium on Neurodegeneration in Aging (CCNA) was developed.

Results

The CCNA gait assessment includes preferred and fast pace gait, and dual-task gait that comprises walking while performing three cognitively demanding tasks: counting backwards by ones, counting backwards by sevens, and naming animals. This gait protocol can be implemented using an electronic-walkway, as well as by using a regular stopwatch. The latter approach provides a simple manner to evaluate quantitative gait performance in clinics.

Conclusions

Establishing a standardized gait assessment protocol will help to assess motor–cognitive interactions in aging and neurodegeneration, to compare results across studies, and to feasibly implement and translate gait testing in clinics for detecting impending cognitive and mobility decline.

Day-to-Day Variability of Postural Sway and Its Association With Cognitive Function in Older Adults: A Pilot Study

Introduction: Increased variability in motor function has been observed during the initial stages of cognitive decline. However, the natural variability of postural control, as well as its association with cognitive status and decline, remains unknown. The objective of this pilot study was to characterize the day-to-day variability in postural sway in non-demented older adults. We hypothesized that older adults with a lower cognitive status would have higher day-to-day variability in postural sway. Materials and Methods: A Nintendo Wii balance board (WBB) was used to quantify postural sway in the home twice daily for 30 days in 20 non-demented, community-dwelling older adults: once under a single-task condition and once under a dual-task condition (using a daily word search task administered via a Nook tablet). Mean sway distance, velocity, area, centroidal frequency and frequency dispersion were derived from the center of pressure data acquired from the WBB. Results: Linear relationships were observed between the day-to-day variability in postural sway and cognitive status (indexed by cognitive global z-scores). More variability in time-domain postural sway (sway distance and area) and less variability in frequency-domain postural sway (centroidal sway frequency) were associated with a lower cognitive status under both the single- and dual-task conditions. Additionally, lower cognitive performance rates on the daily word search task were related to a lower cognitive status. Discussion: This small pilot study conducted on a short time scale motivates large-scale implementations over more extended time periods. Tracking longitudinal changes in postural sway may further our understanding of early-stage postural decline and its association with cognitive decline and, in turn, may aid in the early detection of dementia during preclinical stages when the utility of disease-modifying therapies would be greatest.

Motor Phenotype in Neurodegenerative Disorders: Gait and Balance Platform Study Design Protocol for the Ontario Neurodegenerative Research Initiative (ONDRI)

Background:

The association of cognitive and motor impairments in Alzheimer’s disease and other neurodegenerative diseases is thought to be related to damage in the common brain networks shared by cognitive and cortical motor control processes. These common brain networks play a pivotal role in selecting movements and postural synergies that meet an individual’s needs. Pathology in this “highest level” of motor control produces abnormalities of gait and posture referred to as highest-level gait disorders. Impairments in cognition and mobility, including falls, are present in almost all neurodegenerative diseases, suggesting common mechanisms that still need to be unraveled.

Objective:

To identify motor-cognitive profiles across neurodegenerative diseases in a large cohort of patients.

Methods:

Cohort study that includes up to 500 participants, followed every year for three years, across five neurodegenerative disease groups: Alzheimer’s disease/mild cognitive impairment, frontotemporal degeneration, vascular cognitive impairment, amyotrophic lateral sclerosis, and Parkinson’s disease. Gait and balance will be assessed using accelerometers and electronic walkways, evaluated at different levels of cognitive and sensory complexity, using the dual-task paradigm.

Results:

Comparison of cognitive and motor performances across neurodegenerative groups will allow the identification of motor-cognitive phenotypes through the standardized evaluation of gait and balance characteristics.

Conclusions:

As part of the Ontario Neurodegenerative Research Initiative (ONDRI), the gait and balance platform aims to identify motor-cognitive profiles across neurodegenerative diseases. Gait assessment, particularly while dual-tasking, will help dissect the cognitive and motor contribution in mobility and cognitive decline, progression to dementia syndromes, and future adverse outcomes including falls and mortality.

Using concurrent gait and cognitive assessments to identify impairments after concussion: a narrative review

Understanding how a concussion affects an individual is oftentimes difficult for clinicians due to the varying symptom profiles reported by the patient and the multifaceted and heterogeneous nature of the injury. Accordingly, the interpretation of postconcussion performance can be challenging, because many different testing paradigms have been reported as potentially useful in the literature. Among the types of tests clinicians use to understand how concussion affects an individual, both gait and neurocognitive evaluations have demonstrated utility. Our purpose is to describe how combined gait and cognitive (i.e., dual task), as well as single-task gait and computerized neurocognitive examinations can assist clinical decision-making.