Cognitive function and gait speed under normal and dual-task walking among older adults with mild cognitive impairment

Executive functions and working memory in motor control: Does the type of MCI matter?

The purpose of this study was to evaluate the association between functional mobility performance and executive functions in older adults with the amnestic (aMCI) and nonamnestic (naMCI) type of mild cognitive impairment (MCI), as well as in a control group. A cross-sectional study was conducted among 800 older adults (147 with MCI) who participated in a longitudinal study consisting in an interdisciplinary geriatric assessment and rehabilitation program in Kraków. Motor performance was measured with the Timed Up and Go test (TUG), while standard neuropsychological tests were used to assess different cognitive domains. Analysis of the entire sample showed that almost all cognitive domains and the presence of MCI are associated with functional mobility. Executive functions, letter fluency, and working memory were associated with TUG in the MCI group. The MCI type was not a significant moderator of the relationship between cognitive and motor performance. In group analyses, various cognitive predictors for TUG in the aMCI group, naMCI, and control group were demonstrated. Our results suggest that executive functions and working memory in aMCI and letter fluency in naMCI are independently associated with functional mobility performance. Executive functions are important for gait control in MCI.

Sarcopenia Is Associated with Cognitive Impairment Mainly Due to Slow Gait Speed: Results from the Korean Frailty and Aging Cohort Study (KFACS)

Sarcopenia and cognitive impairment may share common risk factors and pathophysiological pathways. We examined the association between impairments in specific cognitive domains and sarcopenia (and its defining components) in community-dwelling older adults. We analyzed 1887 patients who underwent cognitive function tests and dual-energy X-ray absorptiometry from the baseline data of adults aged 70-84 years obtained from the Korean Frailty and Aging Cohort Study. Those with disability in activities of daily living, dementia, severe cognitive impairment, Parkinson's disease, musculoskeletal complaints, neurological disorders, or who were illiterate were excluded. Cognitive function was assessed using the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet, the Frontal Assessment Battery. For sarcopenia, we used the diagnostic criteria of the Asian Working Group for Sarcopenia. The prevalence of sarcopenia was 9.6% for men and 7.6% for women. Sarcopenia (odds ratio [OR] 1.76, 95% confidence interval [CI] 1.04-2.99) and slow gait speed (OR 2.58, 95% CI 1.34-4.99) were associated with cognitive impairment in men. Only slow gait speed (OR 1.88, 95% CI 1.05-3.36) was associated with cognitive impairment in women. Sarcopenia is associated with cognitive impairment mainly due to slow gait speed. Our results suggested that cognitive impairment domains, such as processing speed and executive function, are associated with sarcopenia-related slow gait speed.

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.

Combining a high DHA multi-nutrient supplement with aerobic exercise: Protocol for a randomised controlled study assessing mobility and cognitive function in older women

There is a complex interplay between cognition and gait in older people, with declines in gait speed coexisting with, or preceding cognitive decline. Omega-3 fatty acids, B vitamins, vitamin E, phosphatidylserine, and Ginkgo Biloba show promise in preserving mobility and cognitive function in older adults. Exercise benefits mobility and there is evidence suggesting positive interactions between exercise and omega-3 fatty acids on physical and cognitive function in older adults. Non-frail or pre-frail females aged ≥60 years are included in a randomized placebo controlled study. Intervention groups are: high DHA multi-nutrient supplement and exercise, placebo supplement and exercise, high DHA multi-nutrient supplement, and placebo supplement. Dietary supplementation is 24 weeks. The exercise intervention, two cycle ergometer classes per week, is for the final 12 weeks. The primary outcome is habitual walking speed, secondary outcomes include gait variables under single and dual task, five times sit to stand, verbal and spatial memory, executive function, interference control and health related quality of life. Blood fatty acids, serum homocysteine, dietary intake, physical activity, and verbal intelligence are measured to assess compliance and control for confounding factors. The study is registered at www.clinicaltrials.gov (NCT03228550).

Gray matter volume covariance patterns associated with gait speed in older adults: a multi-cohort MRI study

Accelerated gait decline in aging is associated with many adverse outcomes, including an increased risk for falls, cognitive decline, and dementia. Yet, the brain structures associated with gait speed, and how they relate to specific cognitive domains, are not well-understood. We examined structural brain correlates of gait speed, and how they relate to processing speed, executive function, and episodic memory in three non-demented and community-dwelling older adult cohorts (Overall N = 352), using voxel-based morphometry and multivariate covariance-based statistics. In all three cohorts, we identified gray matter volume covariance patterns associated with gait speed that included brain stem, precuneus, fusiform, motor, supplementary motor, and prefrontal (particularly ventrolateral prefrontal) cortex regions. Greater expression of these gray matter volume covariance patterns linked to gait speed were associated with better processing speed in all three cohorts, and with better executive function in one cohort. These gray matter covariance patterns linked to gait speed were not associated with episodic memory in any of the cohorts. These findings suggest that gait speed, processing speed (and to some extent executive functions) rely on shared neural systems that are subject to age-related and dementia-related change. The implications of these findings are discussed within the context of the development of interventions to compensate for age-related gait and cognitive decline.

Gait and dementia

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

Maximum gait speed is associated with a wide range of cognitive functions in Japanese older adults with a Clinical Dementia Rating of 0.5

AIM

Physical and cognitive functions are mutually associated. However, it is unknown which markers of physical functions or body composition are most strongly associated with cognition. Here, we explored the association between body composition/physical performance and comprehensive neuropsychological assessments in an effort to identify reliable markers of cognition among factors in body composition/physical performance, including both usual and maximum gait speeds.

METHODS

We examined a total of 161 Japanese individuals (71 men, 90 women; aged 76.3 ± 7.2 years) with a Clinical Dementia Rating of 0.5 and a Mini-Mental State Examination score >24. A battery of neuropsychological assessments, physical functional assessments and measurements of body composition was carried out. We conducted a multiple regression analysis to investigate the associations between cognitive performance and the factors in body composition and physical performance with adjustments for age, sex, and number of school years.

RESULTS

Maximum gait speed was the factor most widely associated with cognitive performance among the factors of body composition and physical performance.

CONCLUSION

Maximum gait speed might be the best marker for cognition in this population of older individuals. Geriatr Gerontol Int 2018; 18: 1323-1329.

The effect of gait speed and gait phase to the allocation of attention during dual task gait

[Purpose] The purpose of this study was to determine the change of allocation of attention caused by a difference in gait phase and gait speed. We also determined the relationship between attentional demand and gait automaticity change caused by the gait speed alteration. [Subjects and Methods] Ten male participated. Participants were instructed to perform the probe reaction time (RT) task during treadmill walking in four different gait speed conditions (60%, 80%, 100%, and 120% of preferred speed). Walking ratio in each gait speed conditions were calculated, and RTs and walking ratios were compared in each gait speed condition and in the single-support and double-support gait phase. [Results] RTs were significantly delayed with decline of gait speed. Walking ratio was significantly decreased in proportion of decrement of gait speed. There was no difference of gait phase between single-support and double-support phase. [Conclusion] This study showed that relationship between attentional load and deficit of gait automaticity. While gait phase didn't influence attentional demand, and this result showed the characteristics of treadmill gait.

Cognitive Dysfunction in Urban-Community Dwelling Prefrail Older Subjects

OBJECTIVES

A number of studies have reported that frailty is cross-sectionally associated with cognitive decline and is also a risk for future cognitive decline or dementia; however, there have been only a few studies that focus on the association between prefrailty and cognitive dysfunction. In the current study, we investigated the association between prefrailty and cognition.

DESIGN

A cross-sectional study of the data obtained at registration in a randomized control trial.

SETTING

Toyota, Japan.

PARTICIPANTS

Community-dwelling older subjects (male 54.6%) who had cognitive complaints.

MEASUREMENTS

A battery of neuropsychological and physical assessments were performed. Prefrailty was defined as exhibiting one or two of the five Fried criteria (weight loss, exhaustion, weakness, slow gait speed and low physical activity). We performed a multiple regression analysis to investigate the associations of cognitive performance with prefrailty, adjusting for the factors that were significantly different between the robust and prefrailty groups. To assess the cognitive attributes that were significantly associated with prefrailty, logistic analysis was performed to see if one specific criterion of the five frailty criteria was associated with cognitive performance.

RESULTS

The study subjects included 183 prefrail and 264 robust individuals. The prefrail subjects with cognitive complaints were older, less educated, more depressive, and more likely to have diabetes mellitus than the robust subjects. The prefrail subjects had lower performance in a wide-range of cognitive domains, and after adjustments for age, education, depressive mood, and diabetes mellitus, prefrailty was associated with a decline in delayed memory and processing speed. Among the components of the Fried criteria, slow gait speed and loss of activity were significantly associated with slow processing speed as assessed by the digit symbol substitution test.

CONCLUSION

The current results demonstrated that prefrailty was associated with worse memory and processing speed performance, but not with other cognitive domains.

Predicting cognitive function of the Malaysian elderly: a structural equation modelling approach

OBJECTIVES

The aim of this study was to identify the predictors of elderly's cognitive function based on biopsychosocial and cognitive reserve perspectives.

METHOD

The study included 2322 community-dwelling elderly in Malaysia, randomly selected through a multi-stage proportional cluster random sampling from Peninsular Malaysia. The elderly were surveyed on socio-demographic information, biomarkers, psychosocial status, disability, and cognitive function. A biopsychosocial model of cognitive function was developed to test variables' predictive power on cognitive function. Statistical analyses were performed using SPSS (version 15.0) in conjunction with Analysis of Moment Structures Graphics (AMOS 7.0).

RESULTS

The estimated theoretical model fitted the data well. Psychosocial stress and metabolic syndrome (MetS) negatively predicted cognitive function and psychosocial stress appeared as a main predictor. Socio-demographic characteristics, except gender, also had significant effects on cognitive function. However, disability failed to predict cognitive function.

CONCLUSION

Several factors together may predict cognitive function in the Malaysian elderly population, and the variance accounted for it is large enough to be considered substantial. Key factor associated with the elderly's cognitive function seems to be psychosocial well-being. Thus, psychosocial well-being should be included in the elderly assessment, apart from medical conditions, both in clinical and community setting.

Association Between Gait and Dual Task With Cognitive Domains in Older People With Cognitive Impairment

The authors investigated whether impaired gait and dual-task performances are associated with specific cognitive domains among older people with preserved cognition (PC), mild cognitive impairment (MCI), and mild Alzheimer's disease (AD). The sample comprised 40 older adults with PC, 40 with MCI, and 38 with mild AD. The assessment consisted of gait (measured by 10-m walk test and Timed Up and Go Test [TUGT]), dual task (measured by TUGT associated with a cognitive-motor task of calling a phone number), and cognition (domains of the Addenbrooke Cognitive Examination-Revised and Frontal Assessment Battery [FAB]). For data analysis, the Pearson product-moment correlation and the backward stepwise linear regression were conducted. Language, fluency, and visuospatial domains predicted the 10-m walk test measure specifically in PC, MCI, and AD groups. Only the visuospatial domain was independently associated with the TUGT measure in the MCI and AD groups. FAB score, language domain, and FAB score and fluency domain were the strongest predictors for the isolated cognitive-motor task measure in the PC, MCI, and AD groups, respectively. The visuospatial domain was independently associated with the dual-task test measure in all 3 groups. The study findings demonstrate the influence of specific cognitive domains in daily mobility tasks in people with different cognitive profiles.

Cognitive impairment associated with locomotive syndrome in community-dwelling elderly women in Japan

In our worldwide aging society, elderly people should maintain cognitive and physical function to help avoid health problems. Dementia is a major brain disease among elderly people, and is caused by cognitive impairment. The locomotive syndrome (LS) refers to a condition in which people require healthcare services because of problems associated with locomotion. The purpose of this study was to determine the association between cognitive impairment and LS. Study participants were 142 healthy elderly female volunteers living in a rural area in Japan. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). A score of ≤26 points on the MMSE was used to indicate categorically defined poor cognitive performance (cognitive impairment). The LS was defined by a score ≥16 points, and non-LS as <16 points, on the 25-question Geriatric Locomotive Function Scale (GLFS-25). Twenty-one participants (14.8%) had an MMSE score ≤26, and 19.0% were found to have LS. Compared with the MMSE >26 group, the ≤26 group was significantly older, had a higher percentage of body fat, and a higher GLFS-25 score. Those with LS were significantly older, had a higher body mass index, a higher percentage of body fat, and a lower MMSE score. Participants in the LS group had higher odds of cognitive impairment than those without LS [odds ratio (OR) =3.08] by logistic regression analysis adjusted for age. Furthermore, participants with GLFS-25 scores ≥6 had higher odds of cognitive impairment than those with a GLFS-25 score <6 by logistic regression analysis adjusted for both age (OR =4.44), and age and percent body fat (OR =4.12). These findings suggest that a strong relationship exists between the early stage of decreased motor function and cognitive impairment.

Loss of gait control assessed by cognitive-motor dual-tasks: pros and cons in detecting people at risk of developing Alzheimer's and Parkinson's diseases

Alzheimer's and Parkinson's diseases are age-related progressive neurodegenerative diseases of increasing prevalence worldwide. In the absence of curative therapy, current research is interested in prevention, by identifying subtle signs of early-stage neurodegeneration. Today, the field of behavioral neuroscience has emerged as one of the most promising areas of research on this topic. Recently, it has been shown that the exacerbation of gait disorders under dual-task conditions (i.e., simultaneous performance of cognitive and motor tasks) could be a characteristic feature of Alzheimer's and Parkinson's diseases. The cognitive-motor dual-task paradigm during walking allows to assess whether (i) executive attention is abnormally impaired in prodromal Alzheimer's disease or (ii) compensation strategies are used in order to preserve gait function when the basal ganglia system is altered in prodromal Parkinson's disease. This review aims at (i) identifying patterns of dual-task-related gait changes that are specific to Alzheimer's and Parkinson's diseases, respectively, (ii) demonstrating that these changes could potentially be used as prediagnostic markers for disease onset, (iii) reviewing pros and cons of existing dual-task studies, and (iv) proposing future directions for clinical research.

Improving Dual-Task Walking Paradigms to Detect Prodromal Parkinson's and Alzheimer's Diseases

Gait control is a complex movement, relying on spinal, subcortical, and cortical structures. The presence of deficits in one or more of these structures will result in changes in gait automaticity and control, as is the case in several neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). By reviewing recent findings in this field of research, current studies have shown that gait performance assessment under dual-task conditions could contribute to predict both of these diseases. Such suggestions are relevant mainly for people at putatively high risk of developing AD (i.e., older adults with mild cognitive impairment subtypes) or PD (i.e., older adults with either Mild Parkinsonian signs or LRRK2 G2019S mutation). Despite the major importance of these results, the type of cognitive task that should be used as a concurrent secondary task has to be selected among the plurality of tasks proposed in the literature. Furthermore, the key aspects of gait control that represent sensitive and specific "gait signatures" for prodromal AD or PD need to be determined. In the present perspective article, we suggest the use of a Stroop interference task requiring inhibitory attentional control and a set-shifting task requiring reactive flexibility as being particularly relevant secondary tasks for challenging gait in prodromal AD and PD, respectively. Investigating how inhibition and cognitive flexibility interfere with gait control is a promising avenue for future research aimed at enhancing early detection of AD and PD, respectively.

Whole-Day Gait Monitoring in Patients with Alzheimer's Disease: A Relationship between Attention and Gait Cycle

Background: Gait impairment in patients with Alzheimer's disease (AD) and its relationship with cognitive function has been described, but reports of gait analysis in AD in daily living are limited. Objective: To investigate whether gait pattern of patients with AD in daily living is associated with cognitive function. Methods: Gait was recorded in 24 patients with AD and 9 healthy controls (HC) for 24 hours by using a portable gait rhythmogram. Mean gait cycle and gait acceleration were compared between the AD and HC groups. For the AD group, these gait metrics were assessed for correlations with cognitive function, as determined by the Mini Mental State Examination and Wechsler Memory Scale-Revised (WMS-R). Results: Although both gait parameters were not different between the patients with AD and HC, gait cycle in patients with AD was positively correlated with attention/concentration scores on the WMS-R (r = 0.578), and not with memory function. Patients with AD with attention scores as high as HC displayed a longer gait cycle than both HC (p = 0.048) and patients with AD with lower attention scores (p = 0.011). The patients with AD with lower attention scores showed a similar gait cycle with HC (p = 0.994). Conclusion: Patients with AD with impaired attentional function walk with faster gait cycle comparable to HC in daily living walking, which was unexpected based on previous gait analysis in clinical settings. This result probably reflects diminished consciousness to either the environment or instability of gait in the patients with AD with impaired attention.

An Examination of Brain Abnormalities and Mobility in Individuals with Mild Cognitive Impairment and Alzheimer's Disease

Background: Mobility changes are concerning for elderly patients with cognitive decline. Given frail older individuals' vulnerability to injury, it is critical to identify contributors to limited mobility. Objective: To examine whether structural brain abnormalities, including reduced gray matter volume and white matter hyperintensities, would be associated with limited mobility among individuals with cognitive impairment, and to determine whether cognitive impairment would mediate this relationship. Methods: Thirty-four elderly individuals with mild cognitive impairment (MCI) and Alzheimer's disease underwent neuropsychological evaluation, mobility assessment, and structural brain neuroimaging. Linear regression was conducted with predictors including gray matter volume in six regions of interest (ROI) and white matter hyperintensity (WMH) burden, with mobility measures as outcomes. Results: Lower gray matter volume in caudate nucleus was associated with slower speed on a functional mobility task. Higher cerebellar volume was also associated with slower functional mobility. White matter hyperintensity burden was not significantly associated with mobility. Conclusion: Our findings provide evidence for associations between subcortical gray matter volume and speed on a functional mobility task among cognitively impaired individuals.

The Associations among Insulin Resistance, Hyperglycemia, Physical Performance, Diabetes Mellitus, and Cognitive Function in Relatively Healthy Older Adults with Subtle Cognitive Dysfunction

Insulin resistance (IR), diabetes mellitus (DM), sarcopenia, and cognitive dysfunction are thought to be mutually associated. We conducted a comprehensive assessment of the relationships among IR, gait speed, hyperglycemia, and DM by cross-sectionally analyzing the baseline data of an interventional study for cognitive preservation with physical exercise (the TOyota Preventional Intervention for Cognitive decline and Sarcopenia [TOPICS]). The participants (n = 444) were relatively healthy older individuals who had mild cognitive impairment without dementia, and 61 of the participants had DM. Slow gait speed and hyperglycemia were associated with cognitive dysfunction, mainly in the executive function domain, whereas IR was associated with memory impairment. The participants with DM had lower general cognition and executive function. Executive dysfunction in the DM participants seemed to be partly explained by hyperglycemia and/or slow gait speed. Our findings confirmed that IR, DM, sarcopenia, and cognitive dysfunction are mutually associated in complex ways. Understanding the mechanisms underlying these associations will lead to effective strategies to prevent and treat cognitive dysfunction in older individuals.

Psychometric properties of dual-task balance and walking assessments for individuals with neurological conditions: A systematic review

BACKGROUND

The ability of performing a balance or walking task in conjunction with a secondary cognitive or motor task, referred to as dual-task (DT) ability, is essential in daily living. While there is some evidence that DT performance is impaired in individuals with neurological conditions, using reliable and valid tools to measure DT performance is essential. This systematic review aimed to evaluate the psychometric properties of DT balance and walking assessments in individuals with different neurological conditions.

METHODS

A systematic literature search was conducted using PubMed, CINAHL, MEDLINE, PsycINFO, SCOPUS, Web of Science, and Cochrane Library (last search done in April 2016). The methodological quality was rated using the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist.

RESULTS

Twenty-three articles involving individuals with stroke, Parkinson's disease, mild cognitive impairment, dementia, Alzheimer's disease, and multiple sclerosis were included. Outcomes derived from the walking tasks under DT condition generally demonstrated good reliability (correlation coefficient ≥0.75) across different neurological disorders, but their usefulness in distinguishing fallers from non-fallers was inconclusive. The reliability of outcomes derived from the cognitive/motor tasks and from the dual-task effect (DTE) (i.e., DT performance minus single-task performance) seemed to be lower but was understudied. The reliability of static or dynamic sitting/standing balance outcomes in DT condition was not assessed in any of the selected studies.

CONCLUSIONS

The reliability of the outcomes derived from walking tasks was good. The psychometric properties of other DT outcomes need to be further investigated.

The effects of a simultaneous cognitive or motor task on the kinematics of walking in older fallers and non-fallers

Human gait has been widely investigated under dual-task conditions because it has been demonstrated to be an important way to uncover differences in gait biomechanics between older fallers and non-fallers. However, exactly how simultaneous tasks affect the kinematics of walking remains unclear. In the present study, gait kinematic properties of older fallers and non-fallers were compared under cognitive and motor dual-task conditions. The gait kinematic properties of interest were recorded under three different conditions: walking at preferred speed, walking when performing a cognitive task (naming animals), and walking when performing a motor task (transferring a coin from one pocket to the other). The following variables were analyzed: gait speed, cadence, stride time, step length, single support, stride time variability, and the dual-task cost. In addition, functional balance was evaluated by means of the Balance Evaluation - Systems Test (BESTest). Two-way repeated-measures ANOVAs revealed significant main effects of walking conditions. However, no significant main effects of group (fallers vs. non-fallers) and no significant interaction effects between group and walking condition were observed. The BESTest revealed that functional balance in fallers was worse than in non-fallers. The cognitive task leads to more significant changes in gait kinematics than does a motor task and the step length and stride time variability were variables more sensitive to that cognitive influence.

Correlation between functional mobility and cognitive performance in older adults with cognitive impairment

Association between cognitive impairment and gait performance occurs in mild cognitive impairment (MCI) and Alzheimer's disease (AD), particularly under "divided attention" conditions, leading to a greater risk of falls. We studied 36 controls, 42 MCI, and 26 mild AD patients, using the Timed Up-and-Go test (TUG) under four conditions: TUG single - TUG1; TUG cognitive - TUG2; TUG manual -TUG3; TUG cognitive and manual - TUG4. Cognition was assessed using the MMSE, SKT, Exit25, and TMT (A and B). We found significant correlations between cognitive scores and TUG2 [r values (MMSE: -0.383, TMT-A: 0.430, TMT-B: 0.386, Exit25: 0.455, SKT: 0.563)] and TUG4 [(MMSE: -0.398, TMT-A: 0.384, TMT-B: 0.352,Exit25: 0.466, SKT: 0.525)] in the AD group, and between all TUG modalities and SKT in MCI and AD. Our results revealed that functional mobility impairment in cognitive dual tasks correlated to cognitive decline in AD patients and to attention and memory impairment in MCI.

Examining interference of different cognitive tasks on voluntary balance control in aging and stroke

This study compared the effect of semantic and working memory tasks when each was concurrently performed with a voluntary balance task to evaluate the differences in the resulting cognitive-motor interference (CMI) between healthy aging and aging with stroke. Older stroke survivors (n = 10), older healthy (n = 10) and young adults (n = 10) performed the limits of stability, balance test under single task (ST) and dual task (DT) with two different cognitive tasks, word list generation (WLG) and counting backwards (CB). Cognitive ability was evaluated by recording the number of words and digits counted while sitting (ST) and during balance tasks (DT). The balance and cognitive costs were computed using [(ST-DT)/ST] × 100 for all the variables. Across groups, the balance cost was significantly higher for the older stroke survivors group in the CB condition than older healthy (p < 0.05) and young adult groups (p < 0.05) but was similar between these two groups for the WLG task. Similarly, the cognitive cost was significantly higher in older stroke survivors than in older healthy (p < 0.05) and young adults (p < 0.01) for both the cognitive tasks. The working memory task resulted in greater CMI than the semantic one, and this difference seemed to be most apparent in older stroke survivors. Young adults showed the least CMI, with a similar performance on the two memory tasks. On the other hand, healthy aging and stroke impact both semantic and working memory. Stroke-related cognitive deficits may further significantly decrease working memory function.

Benefits of a novel concept of home-based exercise with the aim of preventing aspiration pneumonia and falls in frail older women: a pragmatic controlled trial

Aim

To investigate whether home-based exercise with the aim of preventing aspiration pneumonia and accidental falls improves swallowing-related and physical functions in community-dwelling frail older women.

Methods

Participants were 266 community-dwelling frail older women in a long-term care prevention class (mean (SD): age 75 (5) years). Participants were allocated to either an intervention group or a control group. In the intervention group, participants were asked to perform, at least three times a week for 6 months, a home-based exercise programme that was specifically developed to prevent aspiration pneumonia and accidental falls. Control group participants were instructed to perform general stretching exercises only. Voluntary peak cough flow and lip closure force were measured as swallowing-related functions. Static and dynamic balance function, lower limb strength and flexibility were measured as secondary outcomes. Intervention effects were determined using t tests; effect sizes were calculated using Cohen's d.

Results

Voluntary peak cough flow in the intervention group was significantly greater than in the control group (p<0.01, d=0.5). However, lip closure force did not differ between groups. Regarding physical function, results of the Timed Up and Go Test (p<0.05, d=0.4), Chair Stand Test (p<0.01, d=0.4), maximal knee extension strength (p<0.05, d=0.4), and Sit and Reach Test (p<0.05, d=0.3) showed greater improvement in the intervention group.

Conclusions

Specifically developed home-based exercise as described in this study is simple and can be performed briefly. Improvements in voluntary peak cough flow and physical function indicate the possible usefulness of such exercise in preventing falls and aspiration pneumonia in community-dwelling frail older adults.

Trial registration number

UMIN Clinical Trials Registry (UMIN-CTR): UMIN000014880.

Relationship between dual task walking, cognition, and depression in oldest old people

BACKGROUND

The purpose of the study was to investigate the relationship between dual task walking, cognition, and depression in oldest old people living in the community.

METHODS

We conducted an observational cross-sectional study at Federal University of São Carlos (Brazil). We assessed 67 community-dwelling older adults aged 80 years and over, who were able to walk alone and did not present with a risk of dementia (assessed by Mini-Mental State Examination, MMSE). The assessment consisted of anamnesis, dual task using the Timed Up and Go test associated with a motor task (TUGT-motor) and a cognitive task (TUGT-cognitive); cognitive measures using MMSE, Montreal Cognitive Assessment (MoCA), Clock Drawing test (CDT) and verbal fluency, and depressive measures by the Geriatric Depression Scale (GDS).

RESULTS

There was a correlation with higher magnitude between cognitive tests and TUGT-cognitive, compared to TUGT-motor. For TUGT-motor, the highest correlations with cognitive tests were found between time and MMSE, MoCA (total score), and MoCA visuospatial/executive domain. For TUGT-cognitive, the highest correlations with cognitive tests were between number of steps and MMSE and between time and MMSE. GDS showed a significant weak correlation with number of steps taken in TUGT-motor, wrong words, and correct/time of TUGT-cognitive.

CONCLUSIONS

Dual task performances are associated with cognition in oldest old. Furthermore, dual task tests have less influence of educational level, are functional, fast, and easily applicable in clinical practice. Future studies are needed to confirm if dual task test is useful for cognitive screening in oldest old.

Effects of white matter lesions on trunk stability during dual-task walking among older adults with mild cognitive impairment

The linkage between gait and cognition has been shown in cases of white matter lesion (WML) that affect gait in older adults. Dual-task walking is believed to be cognitively demanding and to alter trunk movement, and gait impairment in people with mild cognitive impairment (MCI) is highlighted under this condition. However, the association between dual-task walking and structural changes in the brain, particularly with WML, in people with MCI is still unclear. The aim of this study was to examine the association between trunk stability during dual-task walking and WML in 560 older adults with MCI. We measured magnetic resonance imaging (MRI) and gait variables. Gait variables included harmonic ratio in vertical, mediolateral, and anteroposterior directions, analyzed using a tri-axial accelerometer attached to the lower trunk. Walking conditions were normal walking and dual-task walking (counting backwards while walking) conditions. Demographical data and brain atrophy were measured as covariates. Subjects were classified into non-severe WML (n = 451, mean age = 73.2 years) and severe WML (n = 109, mean age = 75.9 years) groups. Linear mixed-effects model analysis controlled for covariates showed dual-task-related changes in all harmonic ratios associated with WML (p < 0.05). Even after adjustment for executive function, harmonic ratio in the mediolateral direction was significantly associated with WML (p < 0.05). Our findings revealed that WMLs were associated with trunk stability in dual-task walking. Further studies are required to investigate the neural basis for deficits in gait ability among MCI subjects.

Intra-individual lap time variation of the 400-m walk, an early mobility indicator of executive function decline in high-functioning older adults?

Higher intra-individual lap time variation (LTV) of the 400-m walk is cross-sectionally associated with poorer attention in older adults. Whether higher LTV predicts decline in executive function and whether the relationship is accounted for by slower walking remain unanswered. The main objective of this study was to examine the relationship between baseline LTV and longitudinal change in executive function. We used data from 347 participants aged 60 years and older (50.7% female) from the Baltimore Longitudinal Study of Aging. Longitudinal assessments of executive function were conducted between 2007 and 2013, including attention (Trails A, Digit Span Forward Test), cognitive flexibility and set shifting (Trails B, Delta TMT: Trials B minus Trials A), visuoperceptual speed (Digit Symbol Substitution Test), and working memory (Digit Span Backward Test). LTV and mean lap time (MLT) were obtained from the 400-m walk test concurrent with the baseline executive function assessment. LTV was computed as variability of lap time across ten 40-m laps based on individual trajectories. A linear mixed-effects model was used to examine LTV in relation to changes in executive function, adjusted for age, sex, education, and MLT. Higher LTV was associated with greater decline in performance on Trails B (β = 4.322, p < 0.001) and delta TMT (β = 4.230, p < 0.001), independent of covariates. Findings remained largely unchanged after further adjustment for MLT. LTV was not associated with changes in other executive function measures (all p > 0.05). In high-functioning older adults, higher LTV in the 400-m walk predicts executive function decline involving cognitive flexibility and set shifting over a long period of time. High LTV may be an early indicator of executive function decline independent of MLT.

Mild Cognitive Impairment, Slow Gait, and Risk of Disability: A Prospective Study

OBJECTIVES

Mild cognitive impairment (MCI) may be a risk for disability, and co-occurrence of slow gait (SG) and MCI may increase this risk.

DESIGN

Prospective study.

SETTING

General community.

PARTICIPANTS

The study included 3482 older adults (mean age: 71.4 years) without disability at baseline.

MEASUREMENTS

We collected information on demographic variables, measured gait speed and cognitive function to diagnose MCI at baseline. During the follow-up period, the incident disability was monitored. Participants were divided into groups without MCI and SG (control), with SG without MCI (SG), without SG and with MCI in single (sMCI) or multiple (mMCI) domains, and with SG and MCI in single (sMCI + SG) and multiple (mMCI + SG) domains.

RESULTS

During follow-up, 134 participants developed disability (mean follow-up: 29.4 months). The proportions of incident disability were higher in the MCI with SG, MCI, and SG groups, compared with the control group. SG [hazard ratio 2.27 (95% confidence interval: 1.38-3.73)], mMCI [2.56 (1.31-5.02)], sMCI + SG [2.46 (1.21-5.00)], and mMCI + SG [3.48 (1.79-6.76)] participants had risks for disability.

CONCLUSIONS

Co-occurrence of SG and MCI in multiple domains has a higher risk of disability than each condition alone.

Ecological Assessment of Autonomy in Instrumental Activities of Daily Living in Dementia Patients by the Means of an Automatic Video Monitoring System

Currently, the assessment of autonomy and functional ability involves clinical rating scales. However, scales are often limited in their ability to provide objective and sensitive information. By contrast, information and communication technologies may overcome these limitations by capturing more fully functional as well as cognitive disturbances associated with Alzheimer disease (AD). We investigated the quantitative assessment of autonomy in dementia patients based not only on gait analysis but also on the participant performance on instrumental activities of daily living (IADL) automatically recognized by a video event monitoring system (EMS). Three groups of participants (healthy controls, mild cognitive impairment, and AD patients) had to carry out a standardized scenario consisting of physical tasks (single and dual task) and several IADL such as preparing a pillbox or making a phone call while being recorded. After, video sensor data were processed by an EMS that automatically extracts kinematic parameters of the participants’ gait and recognizes their carried out activities. These parameters were then used for the assessment of the participants’ performance levels, here referred as autonomy. Autonomy assessment was approached as classification task using artificial intelligence methods that takes as input the parameters extracted by the EMS, here referred as behavioral profile. Activities were accurately recognized by the EMS with high precision. The most accurately recognized activities were “prepare medication” with 93% and “using phone” with 89% precision. The diagnostic group classifier obtained a precision of 73.46% when combining the analyses of physical tasks with IADL. In a further analysis, the created autonomy group classifier which obtained a precision of 83.67% when combining physical tasks and IADL. Results suggest that it is possible to quantitatively assess IADL functioning supported by an EMS and that even based on the extracted data the groups could be classified with high accuracy. This means that the use of such technologies may provide clinicians with diagnostic relevant information to improve autonomy assessment in real time decreasing observer biases.