Gait dysfunction in mild cognitive impairment syndromes

Gait Performance in People with Symptomatic, Chronic Mild Traumatic Brain Injury

There is a dearth of knowledge about how symptom severity affects gait in the chronic (>3 months) mild traumatic brain injury (mTBI) population despite up to 53% of people reporting persisting symptoms after mTBI. The aim of this investigation was to determine whether gait is affected in a symptomatic, chronic mTBI group and to assess the relationship between gait performance and symptom severity on the Neurobehavioral Symptom Inventory (NSI). Gait was assessed under single- and dual-task conditions using five inertial sensors in 57 control subjects and 65 persons with chronic mTBI (1.0 year from mTBI). The single- and dual-task gait domains of Pace, Rhythm, Variability, and Turning were calculated from individual gait characteristics. Dual-task cost (DTC) was calculated for each domain. The mTBI group walked (domain z-score mean difference, single-task = 0.70; dual-task = 0.71) and turned (z-score mean difference, single-task = 0.69; dual-task = 0.70) slower (p < 0.001) under both gait conditions, with less rhythm under dual-task gait (z-score difference = 0.21; p = 0.001). DTC was not different between groups. Higher NSI somatic subscore was related to higher single- and dual-task gait variability as well as slower dual-task pace and turning (p < 0.01). Persons with chronic mTBI and persistent symptoms exhibited altered gait, particularly under dual-task, and worse gait performance related to greater symptom severity. Future gait research in chronic mTBI should assess the possible underlying physiological mechanisms for persistent symptoms and gait deficits.

Walking-related digital mobility outcomes as clinical trial endpoint measures: protocol for a scoping review

INTRODUCTION

Advances in wearable sensor technology now enable frequent, objective monitoring of real-world walking. Walking-related digital mobility outcomes (DMOs), such as real-world walking speed, have the potential to be more sensitive to mobility changes than traditional clinical assessments. However, it is not yet clear which DMOs are most suitable for formal validation. In this review, we will explore the evidence on discriminant ability, construct validity, prognostic value and responsiveness of walking-related DMOs in four disease areas: Parkinson's disease, multiple sclerosis, chronic obstructive pulmonary disease and proximal femoral fracture.

METHODS AND ANALYSIS

Arksey and O'Malley's methodological framework for scoping reviews will guide study conduct. We will search seven databases (Medline, CINAHL, Scopus, Web of Science, EMBASE, IEEE Digital Library and Cochrane Library) and grey literature for studies which (1) measure differences in DMOs between healthy and pathological walking, (2) assess relationships between DMOs and traditional clinical measures, (3) assess the prognostic value of DMOs and (4) use DMOs as endpoints in interventional clinical trials. Two reviewers will screen each abstract and full-text manuscript according to predefined eligibility criteria. We will then chart extracted data, map the literature, perform a narrative synthesis and identify gaps.

ETHICS AND DISSEMINATION

As this review is limited to publicly available materials, it does not require ethical approval. This work is part of Mobilise-D, an Innovative Medicines Initiative Joint Undertaking which aims to deliver, validate and obtain regulatory approval for DMOs. Results will be shared with the scientific community and general public in cooperation with the Mobilise-D communication team.

REGISTRATION

Study materials and updates will be made available through the Center for Open Science's OSFRegistry (https://osf.io/k7395).

Development of a model on factors affecting instrumental activities of daily living in people with mild cognitive impairment - a Delphi study

Introduction

The level of function of instrumental activities of daily living (IADL) is crucial for a person’s autonomy. A clear understanding of the nature of IADL and its limitations in people with mild cognitive impairment (MCI) is lacking. Literature suggests numerous possible influencing factors, e.g. cognitive function, but has not considered other domains of human functioning, such as environmental factors. Our aim was to develop a comprehensive model of IADL functioning that depicts the relevant influencing factors.

Methods

We conducted a four-round online Delphi study with a sample of international IADL experts (N = 69). In the first round, panelists were asked to mention all possible relevant cognitive and physical function factors, as well as environmental and personal factors, that influence IADL functioning. In the subsequent rounds, panelists rated the relevance of these factors. Consensus was defined as: 1) ≥70% agreement between panelists on a factor, and 2) stability over two successive rounds.

Results

Response rates from the four rounds were high (83 to 100%). In the first round, 229 influencing factors were mentioned, whereof 13 factors reached consensus in the subsequent rounds. These consensual factors were used to build a model of IADL functioning. The final model included: five cognitive function factors (i.e. memory, attention, executive function, and two executive function subdomains -problem solving / reasoning and organization / planning); five physical function factors (i.e. seeing functions, hearing functions, balance, gait / mobility functions and functional mobility functions); two environmental factors (i.e. social network / environment and support of social network / environment); and one personal factor (i.e. education).

Conclusions

This study proposes a comprehensive model of IADL functioning in people with MCI. The results from this Delphi study suggest that IADL functioning is not merely affected by cognitive function factors, but also by physical function factors, environmental factors and personal factors. The multiplicity of factors mentioned in the first round also underlines the individuality of IADL functioning in people with MCI. This model may serve as a basis for future research in IADL functioning in people with MCI.

Prevalence of Falls, Physical Performance, and Dual-Task Cost While Walking in Older Adults at High Risk of Falling with and Without Cognitive Impairment

PURPOSE

To compare the prevalence of falls, physical performance, and dual-task cost during walking between cognitively healthy and impaired older adults at high risk of falling.

METHODS

A cross-sectional analysis of 670 community-dwelling older adults who were considered at high risk of falling, operationalized as 1) having fallen at least once in the preceding 12 months and having a health-care practitioner's referral indicating that the participant was at risk of falls or 2) having impaired mobility as evidenced by a Timed Up and Go (TUG) result ≥13.5 s. Participants (mean age = 77.7 years, SD = 5.6) were divided into cognitively healthy (n = 461) or cognitively impaired (n = 209) groups using a cutoff score of <23 on the Montreal Cognitive Assessment test. Assessment included self-reported number of falls over the previous 12 months, functional reach, TUG, Short Physical Performance Battery (SPPB), and single- and dual-task walk performance. Data were analyzed using Poisson regression to estimate the prevalence ratios of falls and analysis of variance to examine between-group differences on physical performance and dual-task cost during walking performance.

RESULTS

In the analysis, 82.3% of older adults with cognitive impairment and 69.4% of unimpaired older adults reported 1 or more falls in the previous 12 months. Compared with cognitively healthy participants, those with cognitive impairment were 2.57 (95% confidence interval [CI] = 2.17 to 3.05) times more likely to have any fall and 2.33 (95% CI = 1.95 to 2.78) times more likely to have multiple falls. Older adults with cognitive impairment performed worse on functional reach (mean difference [MD] = -2.33 cm, 95% CI = -3.21 to -1.46), TUG (MD = 3.05 s, 95% CI = 2.22 to 3.88), and SPPB (MD = -1.24 points, 95% CI = -1.55 to -0.92) and showed increase in dual-task costs (MD = 6.59%, 95% CI = 4.19 to 9.03) compared to those without cognitive impairment.

CONCLUSION

Older adults at high risk for falls and who have cognitive impairment are associated with a greater risk for falls and decrements in physical and dual-task performance.

Effect of cardiac rehabilitation on cognitive function in elderly patients with cardiovascular diseases

BACKGROUND

Cognitive function is an important factor for secondary prevention in elderly patients with cardiovascular diseases. The objective of this study was to evaluate the impact of cardiac rehabilitation (CR) on the improvement of cognitive function.

METHODS

A total of 66 consecutive elderly patients (≥70 years old) with cardiovascular diseases were prospectively enrolled. The change in cognitive function during 6 months was compared between the patients with monthly CR (at least once per month; n = 27) and those without monthly CR (n = 39). Cognitive function was evaluated using the Mini-mental State Examination (MMSE) and Frontal Assessment Battery (FAB).

RESULTS

There was no significant difference in baseline characteristics between the 2 groups. The change in the MMSE score was significantly greater in patients with monthly CR than in those without monthly CR (2.3 ± 0.4 vs. -0.1 ± 0.3 points; p <0.001). Among the MMSE items, the change in temporal orientation and attention and calculation was significantly greater in the monthly CR group than in the non-monthly CR group (0.8 ± 0.7 vs. -0.1 ± 0.8 points [p <0.001] and 1.0 ± 1.5 vs. -0.1 ± 0.1 points [p <0.001], respectively). The general linear model revealed that monthly CR (effect estimate, 1.455; 95% confidence interval, 0.747-2.163; p <0.001) was independently associated with the change in the MMSE score.

CONCLUSIONS

Cognitive function may improve with regular CR. These results might partly explain the efficacy of CR for secondary prevention.

Relationship Between Balance, Gait, and Activities of Daily Living in Older Adults With Dementia

Introduction:

Gait characteristics are closely associated with executive functions including basic and high-level cognitive processes such as attention, working memory, decision-making, and problem-solving. Impaired cognitive function resulting from dementia is associated with loss of balance and poor activities of daily living (ADLs). If associations between gait parameters, balance, and ADLs are observed, then quantitative gait analysis may be optimal for reinforcing balance and ADL assessments in people with dementia. This study aimed to determine the association between balance, gait, and ADLs in older adults with dementia.

Materials and Methods:

A cross-sectional study was conducted in 46 older adults who have been diagnosed with dementia. Measurements including the Mini-Mental Statement Examination-Korean version (MMSE-K), Berg Balance Scale (BBS), 10-meter walk test (10MWT), Modified Barthel index (MBI), and GAITRite were used to assess cognitive function, balance, walking speed, ADLs, and gait parameters, respectively. The Pearson product correlation coefficient (r) was used for correlation analysis.

Results and Discussion:

Among the gait parameters, velocity was positively associated with the BBS, 10MWT, and MBI (r = 0.341-0.516, P > .05). Step length (r = 0.301-0.586, P > .05), stride length (r = 0.329-0.580, P > .05), and walk ratio (r = 0.324-0.556, P > .05) were positively associated with the MMSE-K, BBS, 10MWT, and MBI. A moderate positive association between single support time and MBI was observed (r = 0.308, P = .039). Additionally, a moderate negative association between double support time and the MBI was observed (r = −0.349, P = .019). This study presents the first empirical evidence on the association between balance, gait, and ADLs in older adults with dementia.

Conclusions:

This study identified important associations between balance, gait, and ADL assessments in people with dementia. Further studies involving targeted interventions addressing gait parameters and improving balance and functional performance in people with dementia are required in the future.

Reduced Walking Speed in Subjective and Mild Cognitive Impairment: A Cross-Sectional Study

BACKGROUND AND PURPOSE

Walking speed is reduced in people with dementia, but less is known about predementia conditions. We, therefore, studied the relationship between walking speed, cognition, and cerebrospinal fluid biomarkers in persons with subjective (SCI) and mild cognitive impairment (MCI).

METHODS

We conducted a cross-sectional study of 22 healthy controls, 30 SCI and 17 MCI (N = 69). Walking speed was measured by a 10-m gait test at usual and fast pace. We analyzed the association between walking speed and the ordered categories of controls, SCI, and MCI in a generalized proportional odds model. Neuropsychological tests, Consortium to Establish a Registry for Alzheimer's Disease (delayed recall), and Trail Making (TMT) A and B, were analyzed by negative binomial, linear, and robust regression for association with walking speed.

RESULTS

Walking speed at usual pace was slower moving from controls to SCI (odds ratio: 0.46, P = 0.031) and MCI (odds ratio: 0.44, P = .019) on an ordinal scale. In MCI, walking speed was reduced at fast speed (odds ratio: 0.46, P = 0.04). There were significant associations between walking speeds and neuropsychological test performance. Usual walking speed was associated with slower test performance on TMT-A (β: -.02, P = .04) and fast pace with slower performance on TMT-B (β: -.01, P = .03). There were no associations between cerebrospinal fluid biomarkers and walking speeds.

CONCLUSION

Usual walking speed is reduced in a graded fashion with the early symptoms of cognitive impairment. Our results suggest that reduced walking speed at both usual and fast speed is associated with impaired cognitive function, and that walking speed could be affected at very early stages of neurodegeneration.

Gait Speed Test and Cognitive Decline in Frail Women With Acute Myocardial Infarction

Women with acute myocardial infarction (AMI) have poorer clinical outcomes than men. Elderly women present high risk of developing frailty and frail women with AMI have a higher prevalence of functional impairments than men on presentation, including physical and cognitive impairment. The Mini-Mental State Examination is a simple test that evaluates global cognitive functions. Gait speed test is a fast, inexpensive, easy measure of physical capacity with documented predictive value for major clinical outcomes. Cognitive and physical decline are very common in frail women, and their prevalence increases with age. On the basis of existing literature, we may speculate that frail women with AMI should be studied with 5-m gait speed test and Mini-Mental State Examination before hospital discharge, for a better evaluation of physical status and global cognitive function.

Age-specific differences in gait domains and global cognitive function in older women: gait characteristics based on gait speed modification

Background

Several studies have reported the association between gait and global cognitive function; however, there is no study explaining the age-specific gait characteristics of older women and association between those characteristics and global cognitive function by age-specific differences and gait speed modification. The aim of this study was to examine age-specific differences in gait characteristics and global cognitive function in older women as well as identify gait domains strongly associated with global cognitive function in older women based on gait speed modification.

Methods

One hundred sixty-four female participants aged 65–85 years were examined. Participants were assessed for global cognitive function through the mini-mental state examination. They also performed three trials of the overground walking test along a straight 20 m walkway. Inertial measurement unit sensors with shoe-type data loggers on both the left and right outsoles were used to measure gait characteristics.

Results

The pace at all speeds and the variability and phase at faster speeds were altered in women aged >75 years (all pace domain parameters, p < 0.05); variability and phase highly depended on age (all p < 0.05). Variability at slower speeds (β = −0.568 and p = 0.006) and the phase at the preferred (β = −0.471 and p = 0.005) and faster speeds (β = −0.494 and p = 0.005) were associated with global cognitive function in women aged >75 years.

Discussion

The variability and phase domains at faster speeds were considered to identify gait changes that accompany aging. In addition, the decreases in global cognitive function are associated with increased variability and phase domains caused by changes in gait speed in older women.

Conclusion

Our results are considered useful for understanding age-related gait characteristics with global cognitive function in old women.

What are the association patterns between handgrip strength and adverse health conditions? A topical review

Measures of handgrip strength can be used to conveniently assess overall muscle strength capacity. Although stand-alone measures of handgrip strength provide robust health information, the clinical meaningfulness to determine prevention and treatment options for weakness remains limited because the etiology of muscle weakness remains unclear. Moreover, clinical outcomes associated with handgrip strength are wide-ranging. Therefore, disentangling how handgrip strength is associated with health conditions that are metabolically or neurologically driven may improve our understanding of the factors linked to handgrip strength. The purpose of this topical review was to highlight and summarize evidence examining the associations of handgrip strength with certain health outcomes that are metabolically and neurologically driven. From this perusal of the literature, we posit that stand-alone handgrip strength be considered an umbrella assessment of the body systems that contribute to strength capacity, and a panoptic measurement of muscle strength that is representative of overall health status, not a specific health condition. Recommendations for future strength capacity–related research are also provided.

Functional connectivity underpinning changes in life-space mobility in older adults with mild cognitive impairment: A 12-month prospective study

Subtle changes in mobility exist among older adults with mild cognitive impairment (MCI). Life-space mobility defines the frequency and extent of movements in the environment, and lower life-space mobility is associated with adverse health outcomes and MCI. Currently, the underlying mechanism of this association is not well understood. This study examined the functional neural correlates of life-space mobility in community-dwelling older adults with MCI. We first conducted a cross-sectional investigation of the association between resting-state default mode network (DMN) and sensori-motor network (SMN) connectivity and life-space mobility (assessed by the Life-Space Assessment (LSA)) among 60 community-dwelling older adults with MCI using aggregated data from two studies - baseline data from a randomized controlled trial (n = 20) and baseline data from a 12-month prospective study (n = 40). Using data from the 12-month prospective study (n = 35), we then examined whether baseline internetwork connectivity predicts reduced life-space mobility over 12 months. The cross-sectional analysis showed higher DMN-SMN connectivity was associated with lower LSA scores after adjusting for baseline global cognitive function and baseline age (p < 0.01). A significant reduction in LSA scores was observed in the 35 participants of the 12-month prospective study (paired sample t-test mean change = -6.53, p = 0.01). Greater baseline DMN-SMN connectivity was associated with greater reduction in life-space mobility at 12 months (p = 0.04) after adjusting for baseline age, global cognitive function, and LSA score. Our findings suggest that lower and reduced life-space mobility in older adults with MCI may be due to altered functional architecture of the brain such that normal neuro-cognitive motor behaviours may be disrupted.

Validity of Instrumented 360° Turn Test in Older Adults with Cognitive Impairment

AIMS

To examine concurrent and construct validity of inertial sensor 360°turn measures in relation with motion capture and mobility assessments in cognitively impaired older adults.

METHODS

Data was collected in 31 participants, mean age 85.2 (SD 5.2), during clockwise (CW) and counter clockwise (CCW) 360° turns using (1) APDM body-worn inertial sensors and (2) Qualisys 8-camera laboratory-based motion capture.

RESULTS

Absolute agreement between inertial sensor and motion capture measures was excellent for turn duration and turn peak velocity (ICC = 0.96-0.98). Strong to moderate correlations were present between inertial sensor turn measures and performance on the Timed Up and Go, Short Physical Performance Battery and 90-s Balance Test. ROC curve analysis of CCW 360° turn duration and turn peak velocity distinguished higher risk versus lower risk for mobility disability.

CONCLUSIONS

Inertial sensor 360° turn measures demonstrated concurrent and construct validity in relation to motion capture and mobility assessments.

The Association of Gait Speed and Frontal Lobe among Various Cognitive Domains: The Korean Frailty and Aging Cohort Study (KFACS)

OBJECTIVE

The aim of this study was to determine how gait speed and frontal lobe functionsin community-dwelling older adults in Korea.

DESIGN

This was a cross-sectional study.

SETTING

The study used data from the Korean Frailty and Aging Cohort Survey (KFACS), a multi-center longitudinal study addressing 10 centers across urban, rural, and suburban communities in Korea, between 2016 and 2017.

PARTICIPANTS

A total of 1552 older adults who underwent both gait speed tests and cognitive functions tests during the investigation of the KFACS.

MEASUREMENTS

Gait speed was assessed by asking participants to walk from a starting point to a point 4 meters away at a normal gait. Cognitive functions were evaluated using various standardized cognitive functions tests.

RESULTS

Gait speed was slower when participants were older or less educated The percentage of women, higher BMI, people with lower incomes, singles, smokers, and drinkers was high in the slower gait group. Also, all cognitive function scores were low and depression score was high in the group with slower walking speed. The slower walking speed showed low physical activity score and high prevalence of hypertension, osteoarthritis and osteoporosis. Among the seven cognitive functions (MMSE, memory, TMT, Recall, Recognition, digit span, and Fab), only TMT showed no significant difference between different gait speed groups. The other six cognitive functions showed higher results in the fastest gait speed group (T3), Participants in middle gait speed group (T2) also showed higher results in five of the seven cognitive function scores as well (Memory, Recall, Recognition, digit span, and Fab).

CONCLUSION

In this study, we found correlation between the slower gait speeds and the decrease in cognitive function, and especially the frontal lobe dysfunction was most prominent of all cognitive dysfunctions.

Relationship Between Mood, Thinking, and Walking: A Systematic Review Examining Depressive Symptoms, Executive Function, and Gait

Prior literature has proposed that the coexistence of late-life depression, executive dysfunction and impaired gait speed may constitute a specific phenotype in older adults with a possible shared brain mechanism. All three conditions are independently associated with negative health outcomes including impaired function, risk of falling, and reduced quality of life. However, the existence, etiology, and implications of having all three conditions as a unitary triad remain unclear. This systematic review examined the literature to assess the consistency of this triad and to explore the possible role of frontal-subcortical circuitry in its etiology. English language literature that assessed mood, executive function, and gait speed using a validated tool in human participants over age 65 were included for this review. Following the PRISMA guidelines, 15 studies including 11,213 participants met criteria for inclusion in this study. The triad's existence was supported by 12 of the 15 studies (80%), including 4 longitudinal studies involving 368 participants. A prevalence of 17% was reported in one population study. The three included intervention studies provided mixed results regarding the benefit of pharmacologic and exercise interventions. Two studies assessed the association between presence of white matter hyperintensities and the triad, with one study finding a significant longitudinal relationship with periventricular white matter hyperintensities. Vascular risk factors were also commonly associated with this triad. Taken together, the relationship between this triad, the vascular depression hypothesis, and frontal-subcortical pathology is suggested. Further longitudinal research is needed to further clarify the etiology and clinical relevance of this concomitant prescence oflate-life depression, executive dysfunction and impaired gait speed.

Differences in Timed Up and Go Subtasks Between Older People With Mild Cognitive Impairment and Mild Alzheimer's Disease

This study compared performances of timed up and go test subtasks between 40 older people with preserved cognition, 40 with mild cognitive impairment, and 38 with mild Alzheimer's disease. The assessment consisted of anamneses and timed up and go test subtasks (sit-to-stand, walking forward, turn, walking back, and turn-to-sit). Data were captured by Qualisys Track Manager software and processed by Visual3D software. The MATLAB program was applied to detect and analyze timed up and go test subtasks. All subtasks differentiated people with Alzheimer's disease and preserved cognition, except the sit-to-stand subtask, which did not distinguish any group. The walking forward subtask differed older people with preserved cognition from mild cognitive impairment, specifically on minimum peak of knee, average value of knee, and hip (pitch axis) during stance phase. The walking back, turn, and turn-to-sit subtasks distinguished subjects with Alzheimer's disease from mild cognitive impairment. The separated analysis of transition and walking subtasks is important in identifying mobility patterns among cognitive profiles.

Selecting Clinically Relevant Gait Characteristics for Classification of Early Parkinson's Disease: A Comprehensive Machine Learning Approach

Parkinson's disease (PD) is the second most common neurodegenerative disease; gait impairments are typical and are associated with increased fall risk and poor quality of life. Gait is potentially a useful biomarker to help discriminate PD at an early stage, however the optimal characteristics and combination are unclear. In this study, we used machine learning (ML) techniques to determine the optimal combination of gait characteristics to discriminate people with PD and healthy controls (HC). 303 participants (119 PD, 184 HC) walked continuously around a circuit for 2-minutes at a self-paced walk. Gait was quantified using an instrumented mat (GAITRite) from which 16 gait characteristics were derived and assessed. Gait characteristics were selected using different ML approaches to determine the optimal method (random forest with information gain and recursive features elimination (RFE) technique with support vector machine (SVM) and logistic regression). Five clinical gait characteristics were identified with RFE-SVM (mean step velocity, mean step length, step length variability, mean step width, and step width variability) that accurately classified PD. Model accuracy for classification of early PD ranged between 73-97% with 63-100% sensitivity and 79-94% specificity. In conclusion, we identified a subset of gait characteristics for accurate early classification of PD. These findings pave the way for a better understanding of the utility of ML techniques to support informed clinical decision-making.

Effects of Chinese square dancing on older adults with mild cognitive impairment

The present study aimed to explore the effects of square dancing on global cognition, depressive symptoms, balance, and quality of life of older adults with mild cognitive impairment. We studied 66 older adults with mild cognitive impairment in a large nursing home. Participants were assigned to the intervention group (n = 33) or the control group (n = 33), according to their residential floor, which was determined by coin tossing. The intervention group underwent a 12-week Chinese square dancing routine, while the control group maintained usual lifestyle (without square dancing). Outcomes were assessed at baseline and at weeks 6 and 12. The results showed positive effects of square dancing on all outcomes assessed, especially on depressive symptoms and quality of life-related mental well-being of the participants. This study showed that square dancing is a promising strategy for older adults with mild cognitive impairment and that long-term adherence can be beneficial.

Minor gait impairment despite white matter damage in pure small vessel disease

OBJECTIVE

Gait impairment is common in patients with cerebral small vessel disease (SVD). However, gait studies in elderly SVD patients might be confounded by age-related comorbidities, such as polyneuropathy or sarcopenia. We therefore studied young patients with the genetically defined SVD CADASIL. Our aim was to examine the effects of pure SVD on single and dual task gait, and to investigate associations of gait performance with cognitive deficits and white matter alterations.

METHODS

We investigated single task walking and calculatory, semantic, or motoric dual task costs in 39 CADASIL patients (mean age 50 ± 8) using a computerized walkway. We obtained 3.0T MRI and neuropsychological data on processing speed, the main cognitive deficit in CADASIL. Spatiotemporal gait parameters were standardized based on data from 192 healthy controls. Associations between white matter integrity, assessed by diffusion tensor imaging, and gait were analyzed using both a global marker and voxel-wise analysis.

RESULTS

Compared to controls, CADASIL patients showed only mild single task gait impairment, and only in the rhythm domain. The semantic dual task additionally uncovered mild deficits in the pace domain. Processing speed was not associated with gait. White matter alterations were related to single task stride length but not to dual task performance.

INTERPRETATION

Despite severe disease burden, gait performance in patients with pure small vessel disease was relatively preserved in single and dual tasks. Results suggest that age-related pathologies other than small vessel disease might play a role for gait impairment in elderly SVD patients.

Early detection of subtle motor dysfunction in cognitively normal subjects with amyloid-β positivity

Since the current neuropsychological assessments are not sensitive to subtle deficits that may be present in cognitively normal subjects with amyloid-β positivity, more accurate and efficient measures are needed. Our aim was to investigate the presence of subtle motor deficits in this population and its relationship with cerebrospinal fluid (CSF) amyloid-β levels. We adapted the Finger Tapping Task to measure tapping speed and intrasubject variability. Seventy-two right-handed participants completed the study. Subjects were divided into three groups according to their CSF biomarker profile: 37 control participants (negative CSF AD biomarkers, CTR), 20 cognitively normal subjects with amyloid-β positivity (abnormal levels of CSF Aβ₄₂, Aβ+) and 15 AD patients. All subjects underwent lumbar puncture for the CSF analysis, apolipoprotein E genotyping and completed the Finger Tapping Task, a neuropsychological battery and cardiovascular risk factor and physical activity assessments. An overall difference between groups was found both in tapping speed [F(2,66) = 19.37, p < .01] and in intrasubject variability [F(2,66) = 11.40, p < .01]. More specifically, the Aβ+ group showed lower speed [F(1,52) = 5.33, p < .05] and greater intrasubject variability [F(1,52) = 8.48, p < .01] than the CTR group, and higher speed than the AD group [F(1,30) = 13.61, p < .01]. Speed (β = .263, p < .05) and intrasubject variability (β = -.558, p < .01) were significantly associated with CSF amyloid-β levels. The present findings suggest that subtle motor difficulties can be detected in cognitively healthy subjects with amyloid-β positivity and be related to CSF Aβ₄₂ levels. An accurate assessment of motor functions could help on identifying individuals at the earliest stage of the Alzheimer's continuum.

Big Data Analytical Approaches to the NACC Dataset: Aiding Preclinical Trial Enrichment

BACKGROUND

Clinical trials increasingly aim to retard disease progression during presymptomatic phases of Mild Cognitive Impairment (MCI) and thus recruiting study participants at high risk for developing MCI is critical for cost-effective prevention trials. However, accurately identifying those who are destined to develop MCI is difficult. Collecting biomarkers is often expensive.

METHODS

We used only noninvasive clinical variables collected in the National Alzheimer's Coordinating Center (NACC) Uniform Data Sets version 2.0 and applied machine learning techniques to build a low-cost and accurate Mild Cognitive Impairment (MCI) conversion prediction calculator. Cross-validation and bootstrap were used to select as few variables as possible accurately predicting MCI conversion within 4 years.

RESULTS

A total of 31,872 unique subjects, 748 clinical variables, and additional 128 derived variables in NACC data sets were used. About 15 noninvasive clinical variables are identified for predicting MCI/aMCI/naMCI converters, respectively. Over 75% Receiver Operating Characteristic Area Under the Curves (ROC AUC) was achieved. By bootstrap we created a simple spreadsheet calculator which estimates the probability of developing MCI within 4 years with a 95% confidence interval.

CONCLUSIONS

We achieved reasonably high prediction accuracy using only clinical variables. The approach used here could be useful for study enrichment in preclinical trials where enrolling participants at risk of cognitive decline is critical for proving study efficacy, and also for developing a shorter assessment battery.

Overlap Between Apolipoprotein Eε4 Allele and Slowing Gait Results in Cognitive Impairment

Background: Although apolipoprotein E polymorphism ε4 allele (ApoE4) and slow gait are well-known risk factors for cognitive impairment, examination of their combined effect on cognitive function is lacking. Our objective was to elucidate whether a combination of ApoE4 phenotyping and slow gait resulted in greater cognitive impairment.

Methods: Overall, 1,085 community-dwelling older adults, either ApoE4 carriers (n = 167, 15.4%) or non-ApoE4 carriers, were included from the “Takashimadaira study.” Gait speed was assessed with an electronic walkway and slow gait was defined as <1 m/s. Cognitive performance was also assessed using the Mini-Mental State Exam (MMSE) and the Trail Making Test (TMT)-A and -B. A two-way analysis of covariance (ANCOVA; ApoE and gait velocity factors) adjusted for covariates was performed for each analysis.

Results: Gait and cognitive performances were similar for ApoE4 and non-ApoE4 carriers. A two-way ANCOVA of the MMSE showed a significant interaction between the two factors. ApoE4 carriers with slow gait had lower MMSE scores than ApoE4 carriers without slow gait and non-ApoE4 carriers with slow gait. Also, a significant main effect of gait velocity on TMT-A was observed, indicating that slow gait is associated with lower scores irrespective of the presence of ApoE4. There was no main effect or interaction observed on the TMT-B.

Conclusions: Our results suggest that the concurrent presence of at least one copy of ApoE4 and slow gait can define a subgroup with the lowest cognition. Elucidating the mechanisms underlying these associations may point out modifiable factors in populations at risk of dementia.

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.

Head over heels but I forget why: Disruptive functional connectivity in older adult fallers with mild cognitive impairment

Disrupted functional connectivity has been highlighted as a neural mechanism by which impaired cognitive function and mobility co-exist in older adults with mild cognitive impairment (MCI). The objective of this study was to determine the independent and combined effects of MCI and faller status on functional connectivity of three functional networks: default mode network (DMN), fronto-parietal network (FPN) and sensorimotor network (SMN) between 4 groups of older adults: 1) Healthy; 2) MCI without Falls; 3) Fallers without MCI; and 4) Fallers with MCI.

METHODS

Sixty-six adults aged 70-80 years old were included. Cognition was assessed using: 1) cognitive dual task; 2) Stroop Colour-Word Test; 3) Trail Making Tests (TMT); and 4) Digit Symbol Substitution Test (DSST). Postural sway was assessed with eyes opened and standing on the floor. Functional connectivity was measured using fMRI while performing a finger-tapping task.

RESULTS

Differences in DMN-SMN connectivity were found for Fallers with MCI vs Fallers without MCI (p = .001). Fallers with MCI had significantly greater postural sway than the other groups. Both DMN-SMN connectivity (p = .03) and postural sway (p = .001) increased in a significantly linear fashion from Fallers without MCI, to MCI without Falls, to Fallers with MCI. Participants with MCI performed significantly worse on the DSST (p = .003) and TMT (p = .007) than those without MCI.

CONCLUSION

Aberrant DMN-SMN connectivity may underlie reduced postural stability. Having both impaired cognition and mobility is associated with a greater level of disruptive DMN-SMN connectivity and increased postural sway than singular impairment.

Accepting the Challenge-Moderate-Intensity Exercise with Individuals with Dementia: A Case Series

Background and purpose:

The global impact of dementia demands a response from researchers and clinicians to not only assist with prevention and a cure, but also to assist in the management of symptoms related to this progressive disease. The purpose of this case series is to highlight the participation of 3 individuals with varying levels of dementia in a moderate-intensity functional exercise program.

Intervention:

The intervention, developed using principles from exercise science and a Strength-Based Approach, consisted of 24 sessions of moderate-intensity exercises delivered in participant’s home.

Outcomes:

Each participant completed a pre- and post-assessment including gait speed, strength, balance, depressive symptoms, cognition, and perceived difficulty with activities of daily living. Despite various clinical presentations, each participant successfully completed all 24 sessions with noted improvements in at least two measures.

Discussion:

These findings highlight the flexibility of using the Strength-Based Approach to enhance participation in a standardized exercise program.

Differential Associations Between Distinct Components of Cognitive Function and Mobility: Implications for Understanding Aging, Turning and Dual-Task Walking

Objective

Cognition and mobility are interrelated. However, this association can be impacted by the specific facets of cognition and mobility that are measured, and further by the different task conditions, e.g., single- versus dual-task walking, under which these associations are evaluated. Systematically studying the multiple facets of cognitive-mobility associations under both the task conditions is critical because both cognition and mobility change with age and pose significant risks associated with falls, morbidity, and disability.

Methods

Using a cross-sectional, prospective study design, data from 124 healthy adults [mean age (SD) = 61.51 (11.90); mean education (SD) = 15.94 (2.18)] were collected. A comprehensive battery of cognitive tests was administered, and gait was assessed using a small, lightweight, three-axis accelerometer with a gyroscope.

Analytical Plan

Data were transformed, and only relatively strong relationships survived after strict statistical criteria adjusting for multiple comparisons were applied. Spearman rho correlation coefficients were used to examine the matrix of correlations between the cognitive-motor variables while adjusting for age and gender.

Results

Executive functions, processing speed, and language were associated with distinct facets of variability, pace, and asymmetry, especially under the dual-task walking condition. Both turns and transitions were also associated with cognition during the Timed Up and Go Task.

Conclusion

Our results extend converging evidence of the involvement of executive functions and processing speed in specific aspects of mobility, along with the role of language. The study has important implications for aging in terms of both assessment and rehabilitation of cognition and gait as well as for the emerging dual-tasking theories and the role of the neural pathways involved in mobility.

Gait Abnormalities and the Risk of Falls in CKD

BACKGROUND AND OBJECTIVES

Older adults with CKD are at high risk of falls and disability. It is not known whether gait abnormalities contribute to this risk.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Quantitative and clinical gait assessments were performed in 330 nondisabled community-dwelling adults aged ≥65 years. CKD was defined as an eGFR <60 ml/min per 1.73 m². Cox proportional hazards models were created to examine fall risk.

RESULTS

A total of 41% (n=134) of participants had CKD. In addition to slower gait speed, participants with CKD had gait cycle abnormalities including shorter stride length and greater time in the stance and double-support phases. Among people with CKD, lower eGFR was independently associated with the severity of gait cycle abnormalities (per 10 ml/min per 1.73 m² lower eGFR: 3.6 cm [95% confidence interval (95% CI), 1.4 to 5.8] shorter stride length; 0.7% [95% CI, 0.3 to 1.0] less time in swing phase; 1.1% [95% CI, 0.5 to 1.7] greater time in double-support phase); these abnormalities mediated the association of lower eGFR with slower gait speed. On clinical gait exam, consistent with the quantitative abnormalities, short steps and marked swaying or loss of balance were more common among participants with CKD, yet most had no identifiable gait phenotype. A gait phenotype defined by any of these abnormal signs was associated with higher risk of falls among participants with CKD: compared with people without CKD and without the gait phenotype, the adjusted hazard ratio was 1.72 (95% CI, 1.06 to 2.81) for those with CKD and the phenotype; in comparison, the adjusted hazard ratio was 0.71 (95% CI, 0.40 to 1.25) for people with CKD but without the phenotype (P value for interaction of CKD status and gait phenotype =0.01).

CONCLUSIONS

CKD in older adults is associated with quantitative gait abnormalities, which clinically manifest in a gait phenotype that is associated with fall risk.

Proposal of a new conceptual gait model for patients with Parkinson's disease based on factor analysis

BACKGROUND

Gait impairment is a risk factor for falls in patients with Parkinson's disease (PD). Gait can be conveniently assessed by electronic walkways, but there is need to select which spatiotemporal gait variables are useful for assessing gait in PD. Existing models for gait variables developed in healthy subjects and patients with PD show some methodological shortcomings in their validation through exploratory factor analysis (EFA), and were never confirmed by confirmatory factor analysis (CFA). The aims of this study were (1) to create a new model of gait for PD through EFA, (2) to analyze the factorial structure of our new model and compare it with existing models through CFA.

RESULTS

From the 37 variables initially considered in 250 patients with PD, 10 did not show good-to-excellent reliability and were eliminated, while further 19 were eliminated after correlation matrix and Kaiser-Meyer-Olkin measure. The remaining eight variables underwent EFA and three factors emerged: pace/rhythm, variability, and asymmetry. Structural validity of our new model was then examined with CFA, using the structural equation modeling. After some modifications, suggested by the Modification Indices, we obtained a final model that showed an excellent fit. In contrast, when the structure of previous models of gait was analyzed, no model achieved convergence with our sample of patients.

CONCLUSIONS

Our model for spatiotemporal gait variables of patients with PD is the first to be developed through an accurate EFA and confirmed by CFA. It contains eight gait variables divided into three factors and shows an excellent fit. Reasons for the non-convergence of other models could be their inclusion of highly inter-correlated or low-reliability variables or could be possibly due to the fact that they did not use more recent methods for determining the number of factors to extract.

An Exploratory Factor Analysis of Sensor-Based Physical Capability Assessment

Physical capability (PC) is conventionally evaluated through performance-based clinical assessments. We aimed to transform a battery of sensor-based functional tests into a clinically applicable assessment tool. We used Exploratory Factor Analysis (EFA) to uncover the underlying latent structure within sensor-based measures obtained in a population-based study. Three hundred four community-dwelling older adults (163 females, 80.9 ± 6.4 years), underwent three functional tests (Quiet Stand, QS, 7-meter Walk, 7MW and Chair Stand, CST) wearing a smartphone at the lower back. Instrumented tests provided 73 sensor-based measures, out of which EFA identified a fifteen-factor model. A priori knowledge and the associations with health-related measures supported the functional interpretation and construct validity analysis of the factors, and provided the basis for developing a conceptual model of PC. For example, the “Walking Impairment” domain obtained from the 7MW test was significantly associated with measures of leg muscle power, gait speed, and overall lower extremity function. To the best of our knowledge, this is the first time that a battery of functional tests, instrumented through a smartphone, is used for outlining a sensor-based conceptual model, which could be suitable for assessing PC in older adults and tracking its changes over time.

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.

The neural correlates of discrete gait characteristics in ageing: A structured review

Gait is complex, described by diverse characteristics underpinned by widespread central nervous system networks including motor and cognitive functions. Despite this, neural substrates of discrete gait characteristics are poorly understood, limiting understanding of gait impairment in ageing and disease. This structured review aims to map gait characteristics, defined from a pre-specified model reflecting independent gait domains, to brain imaging parameters in older adults. Fifty-two studies of 38,029 yielded were reviewed. Studies showed inconsistent approaches when mapping gait assessment to neural substrates, limiting conclusions. Gait impairments typically associated with brain deterioration, specifically grey matter atrophy and white matter integrity loss. Gait velocity, a global measure of gait control, was most frequently associated with these imaging markers within frontal and basal ganglia regions, and its decline predicted from white matter volume and integrity measurements. Fewer studies assessed additional gait measures or functional imaging parameters. Future studies mapping regional neuroanatomical and functional correlates of gait are needed, including those which take a multi-process network perspective to better understand mobility in health and disease.

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.

Digital biomarkers for Alzheimer's disease: the mobile/ wearable devices opportunity

Alzheimer's Disease (AD) represents a major and rapidly growing burden to the healthcare ecosystem. A growing body of evidence indicates that cognitive, behavioral, sensory, and motor changes may precede clinical manifestations of AD by several years. Existing tests designed to diagnose neurodegenerative diseases, while well-validated, are often less effective in detecting deviations from normal cognitive decline trajectory in the earliest stages of the disease. In the quest for gold standards for AD assessment, there is a growing interest in the identification of readily accessible digital biomarkers, which harness advances in consumer grade mobile and wearable technologies. Topics examined include a review of existing early clinical manifestations of AD and a path to the respective sensor and mobile/wearable device usage to acquire domain-centric data towards objective, high frequency and passive digital phenotyping.

Limbic and Basal Ganglia Neuroanatomical Correlates of Gait and Executive Function: Older Adults With Mild Cognitive Impairment and Intact Cognition

OBJECTIVE

This study aimed to examine differences in spatiotemporal gait parameters between older adults with amnestic mild cognitive impairment and normal cognition and to examine limbic and basal ganglia neural correlates of gait and executive function in older adults without dementia.

DESIGN

This was a cross-sectional study of 46 community-dwelling older adults, ages 70-95 yrs, with amnestic mild cognitive impairment (n = 23) and normal cognition (n = 23). Structural magnetic resonance imaging was used to attain volumetric measures of limbic and basal ganglia structures. Quantitative motion analysis was used to measure spatiotemporal parameters of gait. The Trail Making Test was used to assess executive function.

RESULTS

During fast-paced walking, older adults with amnestic mild cognitive impairment demonstrated significantly slower gait speed and shorter stride length compared with older adults with normal cognition. Stride length was positively correlated with hippocampal, anterior cingulate, and nucleus accumbens volumes (P < 0.05). Executive function was positively correlated with hippocampal, anterior cingulate, and posterior cingulate volumes (P < 0.05).

CONCLUSIONS

Compared with older adults with normal cognition, those with amnestic mild cognitive impairment demonstrated slower gait speed and shorter stride length, during fast-paced walking, and lower executive function. Hippocampal and anterior cingulate volumes demonstrated moderate positive correlation with both gait and executive function, after adjusting for age.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) discuss gait performance and cognitive function in older adults with amnestic mild cognitive impairment versus normal cognition, (2) discuss neurocorrelates of gait and executive function in older adults without dementia, and (3) recognize the importance of assessing gait speed and cognitive function in the clinical management of older adults at risk for dementia.

LEVEL

Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 0.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

The Role of Movement Analysis in Diagnosing and Monitoring Neurodegenerative Conditions: Insights from Gait and Postural Control

Quantifying gait and postural control adds valuable information that aids in understanding neurological conditions where motor symptoms predominate and cause considerable functional impairment. Disease-specific clinical scales exist; however, they are often susceptible to subjectivity, and can lack sensitivity when identifying subtle gait and postural impairments in prodromal cohorts and longitudinally to document disease progression. Numerous devices are available to objectively quantify a range of measurement outcomes pertaining to gait and postural control; however, efforts are required to standardise and harmonise approaches that are specific to the neurological condition and clinical assessment. Tools are urgently needed that address a number of unmet needs in neurological practice. Namely, these include timely and accurate diagnosis; disease stratification; risk prediction; tracking disease progression; and decision making for intervention optimisation and maximising therapeutic response (such as medication selection, disease staging, and targeted support). Using some recent examples of research across a range of relevant neurological conditions-including Parkinson's disease, ataxia, and dementia-we will illustrate evidence that supports progress against these unmet clinical needs. We summarise the novel 'big data' approaches that utilise data mining and machine learning techniques to improve disease classification and risk prediction, and conclude with recommendations for future direction.

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.

Eye movements - an early marker of cognitive dysfunctions

Cognitive impairments or dysfunctions are one of the major issues of aging population and medical conditions like brain damage, stroke etc. Assessment of cognitive functioning is usually done by medical practitioners using various standard psychological tests which require expert interventions. In the present study we have tried to use eye tracking as a possible option for assessment of cognitive functions while executing a digitized digit symbol substitution task. The standard task has been modified so that more detail insights of one's cognitive state can be obtained without any manual intervention. Results show that it is possible to get more information like attention, perception etc. It also gives insight about the performance of an individual and can be used for analyzing the executive functions like processing speed, memory etc.

Association between gait and cognition in an elderly population based sample

BACKGROUND

Gait is thought to have a cognitive component, but the current evidence in healthy elderly is mixed. We studied the association between multiple gait and cognitive measures in a cohort of older people.

METHODS

One hundred and seventy-eight cognitively healthy participants from the Whitehall II Imaging Sub-study had a detailed clinical and neuropsychological assessment, as well as an MRI scan. Spatiotemporal and variability gait measures were derived from two 10 m walks at self-selected speed. We did a linear regression analysis, entering potential confounders with backwards elimination of variables with p ≥ 0.1. The remaining variables were then entered into a second regression before doing a stepwise analysis of cognitive measures, entering variables with p < 0.05 and removing those with p ≥ 0.1.

RESULTS

Amongst absolute gait measures, only greater stride length was associated with better performance on the Trail Making Test A (p = 0.023) and the Boston Naming Test (p = 0.042). The stride time variability was associated with performance on the Trail Making Test A (p = 0.031). Age was associated with poorer walking speed (p = 0.014) and stride time (p = 0.011), female sex with shorter stride time (p = 0.000) and shorter double stance (p = 0.005). Length of full-time education was associated with faster walking speed (p = 0.012) and shorter stride time (p = 0.045), and a history of muscular-skeletal disease with slower walking speed (p = 0.01) and shorter stride length (p = 0.015). Interestingly, volume of white matter hyperintensities (WMH) on FLAIR MRI images did not contribute independently to any of the gait measures (p > 0.05).

CONCLUSIONS

No strong relationship between gait and non-motor cognition was observed in a cognitively healthy, high functioning sample of elderly. Nevertheless, we found some relationships with spatial, but not temporal gait which warrant further investigation. WMH made no independent contributionto gait.

[Modern views on gait impairment in Parkinson`s disease and its correction]

The article reviews the causes of gait impairment in patients with Parkinson's disease (PD). The emphasis is made on modern ideas, according to which gait impairment in PD is caused by a multisystem lesion and non-dopaminergic dependent mechanisms play the leading role. It is highlighted that gait impairment in PD is associated with the disruption of frontal/subcortical neural pathways which requires a special approach to pharmacological and non-pharmacological therapy. Based on pathogenetic mechanisms, much attention is paid to anti-dementia medications. Attention is drawn to the fact that the use of memantine hydrochloride (akatinol memantine) is a promising direction for gait impairment correction in the advanced and late stages of PD due to the improvement of glutamatergic transfer from the striatum to the specific areas of the cerebral cortex involved in gait control. The results of the latest clinical trials are analyzed.

Gait Patterns in Parkinson's Disease with or without Cognitive Impairment

Background and Purpose

Cognitive and gait disturbance are common symptoms in Parkinson's disease (PD). Although the relationship between cognitive impairment and gait dysfunction in PD has been suggested, specific gait patterns according to cognition are not fully demonstrated yet. Therefore, the aim of this study was to investigate gait patterns in PD patients with or without cognitive impairment.

Methods

We studied 86 patients at an average of 4.8 years after diagnosis of PD. Cognitive impairment was defined as scoring 1.5 standard deviation below age- and education-specific means on the Korean version of the Mini-Mental State Examination (K-MMSE). Three-dimensional gait analysis was conducted for all patients and quantified gait parameters of temporal-spatial data were used. Relationships among cognition, demographic characteristics, clinical features, and gait pattern were evaluated.

Results

Cognitive impairment was observed in 41 (47.7%) patients. Compared to patients without cognitive impairment, patients with cognitive impairment displayed reduced gait speed, step length, and stride length. Among K-MMSE subcategories, “registration,” “attention/calculation,” and “visuospatial function” were significantly associated with speed, step length, and stride length. However, age, disease duration, Hoehn-Yahr (HY) stage, or Unified Parkinson's Disease Rating Scale (UPDRS) motor score was not significantly related to any gait analysis parameter.

Conclusions

Our present study shows that cognitive impairment is associated with slow and short-stepped gait regardless of HY stage or UPDRS motor score, suggesting that cognitive impairment may serve as a surrogate marker of gait disturbance or fall in PD patients.