Simultaneously Measuring Gait and Cognitive Performance in Cognitively Healthy and Cognitively Impaired Older Adults: The Basel Motor-Cognition Dual-Task Paradigm

Development and External Validation of a Gait Test Based Diagnostic Model for Detecting Mild Cognitive Impairment

OBJECTIVE

To address the lack of large-scale screening tools for mild cognitive impairment (MCI), this study aimed to assess the discriminatory ability of several gait tests for MCI and develop a screening tool based on gait test for MCI.

DESIGN

A diagnostic case-control test.

SETTING

The general community.

PARTICIPANTS

We recruited 134 older adults (≥65 years) for the derivation sample, comprising -69 individuals in the cognitively normal group and -65 in the MCI group (N=134). An additional 70 participants were enrolled for the validation sample.

INTERVENTIONS

All participants completed gait tests consisting of a single task (ST) and 3 dual tasks (DTs): counting backwards, serial subtractions 7, and naming animals.

MAIN OUTCOME MEASURES

Binary logistic regression analyses were used to develop models, and the efficacy of each model was assessed using receiver operating characteristic (ROC) curve and area under the curve (AUC). The best effective model was the final diagnostic model and validated using ROC curve and calibration curve.

RESULTS

The DT gait test incorporating serial subtractions 7 as the cognitive task demonstrated the highest efficacy with the AUC of 0.906 and the accuracy of 0.831 in detecting MCI with "years of education" being adjusted. Furthermore, the model exhibited consistent performance across different age and sex groups. In external validation, the model displayed robust discrimination (AUC=0.913) and calibration (calibrated intercept=-0.062, slope=1.039).

CONCLUSIONS

The DT gait test incorporating serial subtractions 7 as the cognitive task demonstrated robust discriminate ability for MCI. This test holds the potential to serve as a large-scale screening tool for MCI, aids in the early detection and intervention of cognitive impairment in older adults.

Spatiotemporal gait characteristics across the adult lifespan: Reference values from a healthy population - Analysis of the COmPLETE cohort study

BACKGROUND

Gait changes with aging have been investigated, but few studies have examined a wide range of gait parameters across the adult lifespan. This study aimed to investigate gait differences across age groups stratified by sex.

METHODS

This cross-sectional study included 629 healthy, normal-weight (i.e., BMI < 30 kg/m2) participants from Switzerland of the COmPLETE cohort study, aged 20 to over 90 years. Gait metrics were assessed using an inertial measurement unit (IMU)-based gait analysis system, including speed, cycle duration variability, asymmetry, stride length, cycle duration, cadence, double support, stance (time foot is on the ground during a gait cycle), swing (time foot is in the air during a gait cycle), loading (early part of the stance phase), foot-flat (mid-stance phase when foot is flat), and pushing (late stance phase leading to toe-off) phases. Percentile curves were calculated using generalized additive models for location, scale, and shape.

RESULTS

Gait data from 545 participants (273 men and 272 women) were analyzed. Participants were equally distributed across the seven age decades, with an average of 40 men and 40 women representing every decade. Both men and women showed a reduction in gait speed and stride length, and an increase in cycle duration variability and asymmetry with aging. Gait speed and stride length declined across the age groups, with a significant difference found in participants aged 80 to 91 compared to younger age groups.

SIGNIFICANCE

Age-related changes in gait parameters were seen in both men and women. These may be attributed to the typical decline in muscle strength, balance, coordination, and neuromuscular function. The results of this study contribute to the understanding of gait changes throughout the lifespan and can be used for comparison with other populations and as reference values for individual patients.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Immersive Virtual Reality Reaction Time Test and Relationship with the Risk of Falling in Parkinson's Disease

Immersive virtual reality (IVR) uses customized and advanced software and hardware to create a digital 3D reality in which all of the user's senses are stimulated with computer-generated sensations and feedback. This technology is a promising tool that has already proven useful in Parkinson's disease (PD). The risk of falls is very high in people with PD, and reaction times and processing speed may be markers of postural instability and functionality, cognitive impairment and disease progression. An exploratory study was conducted to explore the feasibility of reaction time tests performed in IVR as predictors of falls. A total of 26 volunteers (79.2% male; 69.73 ± 6.32 years) diagnosed with PD (1.54 ± 0.90 H&Y stage; 26.92 ± 2.64 MMSE) took part in the study. IVR intervention was feasible, with no adverse effects (no Simulator Sickness Questionnaire symptoms). IVR reaction times were related (Spearman's rho) to functionality (timed up and go test (TUG) (rho = 0.537, p = 0.005); TUG-Cognitive (rho = 0.576, p = 0.020); cognitive impairment mini mental state exam (MMSE) (rho = -0.576, p = 0.002)) and the years of the patients (rho = 0.399, p = 0.043) but not with the first PD symptom or disease stage. IVR test is a complementary assessment tool that may contribute to preventing falls in the proposed sample. Additionally, based on the relationship between TUG and reaction times, a cut-off time is suggested that would be effective at predicting the risk of suffering a fall in PD patients using a simple and quick IVR test.

Dual-Task Interference Slows Down Proprioception

It is well-known that multitasking impairs the performance of one or both of the concomitant ongoing tasks. Previous studies have mainly focused on how a secondary task can compromise visual or auditory information processing. However, despite dual tasking being critical to motor performance, the effects of dual-task performance on proprioceptive information processing have not been studied yet. The purpose of the present study was, therefore, to investigate whether sensorimotor task performance would be affected by the dual task and if so, in which phase of the sensorimotor task performance would this negative effect occur. The kinematic variables of passive and active knee movements elicited by the leg drop test were analyzed. Thirteen young adults participated in the study. The dual task consisted of performing serial subtractions. The results showed that the dual task increased both the reaction time to counteract passive knee-joint movements in the leg drop test and the threshold to detect those movements. The dual task did not affect the speed and time during the active knee movement and the absolute angle error between the final and the target knee angles. Furthermore, the results showed that the time to complete the sensorimotor task was prolonged in dual tasking. Our findings suggest that dual tasking reduces motor performance due to slowing down proprioceptive information processing without affecting movement execution.

Effects of age, sex, frailty and falls on cognitive and motor performance during dual-task walking in older adults

BACKGROUND

Dual-task (DT) walking is of great interest in clinical evaluation to evaluate the risk of falling or cognitive declines in older adults. However, it appears necessary to investigate deeply the confounding factors to better understand their impact on dual-task performance.

OBJECTIVE

To evaluate the effect of age, sex, falls and frailty on cognitive and motor parameters in dual-task walking.

SUBJECTS

66 older participants (mean age = 75.5 ± 6.3; mean height = 165.8 ± 8.4 cm; mean weight = 68.4 ± 14 kgs) were split into groups based on their age, sex, fall and frailty status.

METHODS

Participants performed single-task walking, single-task cognitive (serial subtraction of 3), and dual-task walking (subtraction + walking) for 1 min at their fast pace. Gait speed, step length, step length variability, stance and swing phase time, single and double support, cadence, step time variability and gait speed variability were recorded in single- and dual-task walking and used to calculate the dual-task effect (DTE) as ((DT - ST) / ST) ∗ 100). The cognitive score (DTEcog) was calculated as the number of correct responses minus errors. Generalized linear mixed models (GLMM) were used to compare the effects of falls, frailty, age and sex on gait and cognitive variables.

RESULTS

The interaction frailty*sex and frailty*age were the major effect on the DTEs. Specifically, the DTE was higher in women than men and in the frail group compared to non-frail.

CONCLUSIONS

The present findings provide a better understanding on the confounding factors explaining the behavior in DT that could be used to develop more effective dual-task clinical programs for community-living older adults.

[Music and exercise as therapeutic resources in dementia]

Music and exercise have played a major role in the care of people with dementia for decades. The scientific evidence for such interventions is still relatively scarce but growing. The fact which has been known for nearly 10 years that brain regions associated with musical long-term memory remain intact up to advanced stages of dementia made music a major therapeutic resource in cognitive decline. Therefore, sung texts are learned and recalled better than spoken texts. Furthermore, the specific music-related stimulation of frontal brain regions has frequently shown positive effects on conspicuous behavioral disorders associated with dementia. Exercise in combination with music, in the form of dance or eurhythmics, not only seems to positively affect cognition but also balance and gait safety among patients with dementia.

Neurodegenerative diseases categorization by applying the automatic model selection and hyperparameter optimization method

Neurodegenerative diseases affect a large part of the population in the world and also in Mexico, deteriorating gradually the quality of patients’ life. Therefore, it is important to diagnose them with a high degree of reliability. In order to solve it, various computational methods have been applied in the analysis of biomarkers of human gait. In this study, we propose employing the automatic model selection and hyperparameter optimization method that has not been addressed before for this problem. Our results showed highly competitive percentages of correctly classified instances when discriminating binary and multiclass sets of neurodegenerative diseases: Parkinson’s disease, Huntington’s disease, and Spinocerebellar ataxias.

Dual-task gait and mild behavioral impairment: The Interface between non-cognitive dementia markers

BACKGROUND

Mild behavioral impairment (MBI) and dual-task gait cost (DTGC) are two non-cognitive markers of dementia that capture behavioral and motor symptoms. We investigated the relationship between MBI and DTGC in a sample of non-demented older adults.

METHODS

This was a cross-sectional observational study of 193 participants (10 cognitively normal, 48 subjective cognitive decline (SCD), 135 mild cognitive impairment (MCI); 52.8% female) from 13 Canadian sites from the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) study. The Neuropsychiatric Inventory Questionnaire (NPI-Q) was used to define MBI severity using a published algorithm. DTGC, the percentage difference between dual-task and preferred walking speeds, was assessed under three cognitive tasks: animal naming, counting backwards, and serial seven subtractions. Associations were tested in the entire cohort and in the MCI subgroup using multivariable linear regression adjusted for age, sex, education, and diagnosis. The role of global cognition, executive function, verbal and working memory in the association were investigated using tests of mediation and moderation.

RESULTS

MBI symptoms were present in 46.6% of participants (mean age = 72.4 years). Greater overall MBI burden was associated with lower gait speed across all conditions. Furthermore, a one-point increase in global MBI symptom severity was associated with a 0.8% increase in DTGC in the animal fluency condition, a 0.9% increase in the counting backwards condition and a 1.1% increase in the serial sevens condition. These associations were strongest in the subgroup of MCI participants. Executive function but not global cognition or verbal and working memory mediated the association between MBI and DTGC in all three conditions.

CONCLUSIONS

MBI is associated with gait speed and DTGC in this group of non-demented individuals, independent of the presence or absence of MCI. These findings provide evidence of the relationship between these non-cognitive dementia markers of behavior and gait beyond cognitive impairment.

Theoretical Rationale for Design of Tasks in a Virtual Reality-Based Exergame for Rehabilitation Purposes

Virtual reality games are playing a greater role in rehabilitation settings. Previously, commercial games have dominated, but increasingly, bespoke games for specific rehabilitation contexts are emerging. Choice and design of tasks for VR-games are still not always clear, however; some games are designed to motivate and engage players, not necessarily with the facilitation of specific movements as a goal. Other games are designed specifically for the facilitation of specific movements. A theoretical background for the choice of tasks seems warranted. As an example, we use a game that was designed in our lab: VR Walk. Here, the player walks on a treadmill while wearing a head-mounted display showing a custom-made virtual environment. Tasks include walking on a glass bridge across a drop, obstacle avoidance, narrowing path, walking in virtual footsteps, memory, and selection tasks, and throwing and catching objects. Each task is designed according to research and theory from movement science, exercise science, and cognitive science. In this article, we discuss how for example walking across a glass bridge gives perceptual challenges that may be suitable for certain medical conditions, such as hearing loss, when perceptual abilities are strained to compensate for the hearing loss. In another example, walking in virtual footsteps may be seen as a motor and biomechanical constraint, where the double support phase and base of support can be manipulated, making the task beneficial for falls prevention. In a third example, memory and selection tasks may challenge individuals that have cognitive impairments. We posit that these theoretical considerations may be helpful for the choice of tasks and for the design of virtual reality games.

Effects of task complexity or rate of motor imagery on motor learning in healthy young adults

BACKGROUND

A growing body of evidence suggests the benefit of motor imagery in motor learning. While some studies tried to look at the effect of isolated mental practice, others evaluated the combined effect of motor imagery and physical practice in clinical rehabilitation. This study aimed to investigate the effects of task complexity or rates of motor imagery on motor learning in health young adults.

METHODS

Eighty-eight healthy individuals participated in this study. Participants were randomly allocated to either Group A (50% complex, N = 22), Group B (75% complex, N = 22), Group C (50% simple, N = 22), or Group D (75% simple, N = 22). Participants in the complex groups performed their task with nondominant hand and those in simple groups with a dominant hand. All participants performed a task that involved reach, grasp, and release tasks. The performance of the four groups was examined in the acquisition and retention phase. The main outcome measure was the movement time.

RESULTS

There were significant differences between immediate (i.e., acquisition) and late (i.e., retention) movement times at all three stages of task (i.e., MT1 [reaching time], MT2 [target transport time], and TMT [reaching time plus object transport time]) when individuals performed complex task with 75% imagery rate (p < .05). Similarly, there were significant differences between immediate and late movement times at all stages of task except the MT2 when individuals performed simple task with 75% imagery rate (p < .05). There were significant effects of task complexity (simple vs. complex tasks) on immediate movement time at the first stage of task (i.e., MT1 ) and late movement times of all three stages of task (p < .05). There were significant effects of the rate of imagery (50% vs. 75%) on late movement times at all three stages of tasks (p > .05). Additionally, there were no interaction effects of either task complexity or rate of imagery on both immediate and late movement times at all three stages of tasks (p > .05).

CONCLUSION

This study supports the use of higher rates (75%) of motor imagery to improve motor learning. Additionally, the practice of a complex task demonstrated better motor learning in healthy young adults. Future longitudinal studies should validate these results in different patient's population such as stroke, spinal cord injury, and Parkinson's disease.

The Performance Index Identifies Changes Across the Dual Task Timed Up and Go Test Phases and Impacts Task-Cost Estimation in the Oldest-Old

Introduction: Dual tasking is common in activities of daily living (ADLs) and the ability to perform them usually declines with age. While cognitive aspects influence dual task (DT) performance, most DT-cost (DT-C) related metrics include only time- or speed- delta without weighting the accuracy of cognitive replies involved in the task.

Objectives: The primary study goal was to weight the accuracy of cognitive replies as a contributing factor when estimating DT-C using a new index of DT-C that considers the accuracy of cognitive replies (P-index) in the instrumented timed up and go test (iTUG). Secondarily, to correlate the novel P-index with domains of the Mini-Mental State Examination (MMSE).

Methods: Sixty-three participants (≥85 years old) took part in this study. The single task (ST) and DT iTUG tests were performed in a semi-random order. Both the time taken to complete the task measured utilizing an inertial measurement unit (IMU), and the accuracy of the cognitive replies were used to create the novel P-index. Clinical and sociodemographic data were collected.

Results: The accuracy of the cognitive replies changed across the iTUG phases, particularly between the walk 1 and walk 2 phases. Moreover, weighting 0.6 for delta-time (W₁) and 0.4 for cognitive replies (W₂) into the P-index enhanced the prediction of the MMSE score. The novel P-index was able to explain 37% of the scores obtained by the fallers in the “spatial orientation” and “attention” domains of the MMSE. The ability of the P-index to predict MMSE scores was not significantly influenced by age, schooling, and number of medicines in use. The Bland-Altman analysis indicated a substantial difference between the time-delta-based DT-C and P-index methods, which was within the limits of agreement.

Conclusions: The P-index incorporates the accuracy of cognitive replies when calculating the DT-C and better reflects the variance of the MMSE in comparison with the traditional time- or speed-delta approaches, thus providing an improved method to estimate the DT-C.

Energy optimization during walking involves implicit processing

Gait adaptations, in response to novel environments, devices or changes to the body, can be driven by the continuous optimization of energy expenditure. However, whether energy optimization involves implicit processing (occurring automatically and with minimal cognitive attention), explicit processing (occurring consciously with an attention-demanding strategy) or both in combination remains unclear. Here, we used a dual-task paradigm to probe the contributions of implicit and explicit processes in energy optimization during walking. To create our primary energy optimization task, we used lower-limb exoskeletons to shift people's energetically optimal step frequency to frequencies lower than normally preferred. Our secondary task, designed to draw explicit attention from the optimization task, was an auditory tone discrimination task. We found that adding this secondary task did not prevent energy optimization during walking; participants in our dual-task experiment adapted their step frequency toward the optima by an amount and at a rate similar to participants in our previous single-task experiment. We also found that performance on the tone discrimination task did not worsen when participants were adapting toward energy optima; accuracy scores and reaction times remained unchanged when the exoskeleton altered the energy optimal gaits. Survey responses suggest that dual-task participants were largely unaware of the changes they made to their gait during adaptation, whereas single-task participants were more aware of their gait changes yet did not leverage this explicit awareness to improve gait adaptation. Collectively, our results suggest that energy optimization involves implicit processing, allowing attentional resources to be directed toward other cognitive and motor objectives during walking.

Critical spatiotemporal gait parameters for individuals with dementia: A systematic review and meta-analysis

Instrumented gait analysis allows for the identification of walking parameters to predict cognitive decline and the worsening of dementia. The aim of this study was to perform a meta-analysis to better clarify which gait parameters are affected or modified with the progression of the dementia in a larger sample, as well as which gait assessment conditions (single-task or dual-task conditions) would be more sensitive to reflect the influence of dementia. Literature searches were conducted with the keywords "quantitative gait" OR "gait analysis" AND "dementia" AND "single-task" AND "dual-task," and for "quantitative gait" OR "gait analysis" AND "dementia" AND "fall risk" on PubMed, EMBASE, the Cochrane Library, Scopus, and Web of Science. The results were used to perform a systematic review focussing on instrumental quantitative assessment of the walking of patients with dementia, during both single and dual tasks. The search was performed independently by two authors (C. R. and C. M.) from January 2018 to April 2020 using the PICOS criteria. Nine publications met the inclusion criteria and were included in the systematic review. Our meta-analysis showed that during a single task, most of the spatiotemporal parameters of gait discriminated best between patients with dementia and healthy controls, including speed, cadence, stride length, stride time, stride time variability, and stance time. In dual tasks, only speed, stride length, and stride time variability discriminated between the two groups. In addition, compared with spatial parameters (e.g. stride length), some temporal gait parameters were more correlated to the risk of falls during the comfortable walking in a single task, such as cadence, stride time, stride time variability, and stance time. During a dual task, only the variability of stride time was associated with the risk of falls.

An insight into the role of Artificial Intelligence in the early diagnosis of Alzheimer's disease

BACKGROUND

The complication of Alzheimer's disease (AD) has made the development of its therapeutic a challenging task. Even after decades of research, we have achieved no more than a few years of symptomatic relief. The inability to diagnose the disease early is the foremost hurdle behind its treatment. Several studies have aimed to identify potential biomarkers that can be detected in body fluids (CSF, blood, urine, etc) or assessed by neuroimaging (i.e., PET and MRI). However, the clinical implementation of these biomarkers is incomplete as they cannot be validated.

METHOD

To overcome the limitation, the use of artificial intelligence along with technical tools has been extensively investigated for AD diagnosis. For developing a promising artificial intelligence strategy that can diagnose AD early, it is critical to supervise neuropsychological outcomes and imaging-based readouts with a proper clinical review.

CONCLUSION

Profound knowledge, a large data pool, and detailed investigations are required for the successful implementation of this tool. This review will enlighten various aspects of early diagnosis of AD using artificial intelligence.

Insomnia and falls in older adults: are they linked to executive dysfunction?

BACKGROUND

Insomnia increases the incidence of falls and impairs executive function. Moreover, falls are associated with executive function impairment. The relationship between falls and executive function in patients with insomnia is not clear. The aim of this study was to evaluate relationship between falls and executive function in individuals with insomnia and a control group.

METHODS

This study involved 122 patients (47 insomnia, 75 controls). The Mini-Mental State Examination, Quick Mild Cognitive Impairment Screen, Trail Making Test A, clock-drawing test, and digit span test were used to measure executive function. Semantic and working memory dual task was also performed. Fall history was recorded and the Falls Efficacy Scale - International administered.

RESULTS

The median age of the patients was 71 years (range: 65-89 years), and 60.7% were women. The insomnia group scored lower on the three-word recall than the control group (P = 0.005), but there was no difference between the groups on cognitive tests. Fall history and fear of falling were more frequent in the insomnia group (P = 0.003, P < 0.001). Semantic and working memory dual tasks were correlated with clock-drawing test only in the insomnia group (r = -0.316, P = 0.031; r = -0.319, P = 0.029). Depression (odds ratio (OR) = 9.65, P = 0.001) and Trail Making Test A (OR = 1.025, P = 0.07) were independently associated with insomnia. Four-metre walking speed (OR = 2.342, P = 0.025), insomnia (OR = 3.453; P = 0.028), and the semantic memory dual task (OR = 1.589; P = 0.025) were also independently associated with falls.

CONCLUSION

Our study showed that dual tasking and executive function are related to falls in patients with insomnia. Managing insomnia and assessment of executive dysfunction may have beneficial effects on preventing falls.

Mild Stroke Affects Pointing Movements Made in Different Frames of Reference

Background

Motor performance is a complex process controlled in task-specific spatial frames of reference (FRs). Movements can be made within the framework of the body (egocentric FR) or external space (exocentric FR). People with stroke have impaired reaching, which may be related to deficits in movement production in different FRs.

Objective

To characterize rapid motor responses to changes in the number of degrees of freedom for movements made in different FRs and their relationship with sensorimotor and cognitive impairment in individuals with mild chronic stroke.

Methods

Healthy and poststroke individuals moved their hand along the contralateral forearm (egocentric task) and between targets in the peripersonal space (exocentric task) without vision while flexing the trunk. Trunk movement was blocked in randomized trials.

Results

For the egocentric task, controls produced the same endpoint trajectories in both conditions (free- and blocked-trunk) by preserving similar shoulder-elbow interjoint coordination (IJC). However, endpoint trajectories were dissimilar because of altered IJC in stroke. For the exocentric task, controls produced the same endpoint trajectories when the trunk was free or blocked by rapidly changing the IJC, whereas this was not the case in stroke. Deficits in exocentric movement after stroke were related to cognitive but not sensorimotor impairment.

Conclusions

Individuals with mild stroke have deficits rapidly responding to changing conditions for complex reaching tasks. This may be related to cognitive deficits and limitations in the regulation of tonic stretch reflex thresholds. Such deficits should be considered in rehabilitation programs encouraging the reintegration of the affected arm into activities of daily living.

Cognitive decline negatively impacts physical function

Many older adults report difficulty performing one or more activities of daily living. These difficulties may be attributed to cognitive decline and as a result, measuring cognitive status among aging adults may help provide an understanding of current functional status. The purpose of the present investigation was to determine the association between cognitive status and measures of physical functioning. Seventy-six older adults participated in this study; 41 were categorized as normal memory function (NM) and 35 were poor memory function (PM). NM participants had significantly higher physical function as measured by Short Physical Performance Battery (SPPB; 9.4 ± 2.2 vs. 8.4 ± 2.0; p = .03) and peak velocity (0.67 ± 0.16 vs. 0.56 ± 0.19; p = .04) during a quick sit-to-stand task. Dual-task walking velocities were 22% and 126% slower between cognitive groups for the fast and habitual trials, respectively when compared to the single-task walking condition. Significant correlations existed between measures of memory and physical function. The largest correlations with memory were for peak (r = 0.42) and average (r = 0.38) velocity. The results suggest a positive relationship between physical function and cognitive status. However, further research is needed to determine the mechanism of the underlying relationships between physical and cognitive function.

Impact of cognitive tasks on biomechanical and kinematic parameters of gait in women with fibromyalgia: A cross-sectional study

BACKGROUND

Fibromyalgia (FM) is a chronic disease whose symptoms may cause altered walking pattern, which is important given the relevance of walking in daily life activities. These activities use to require the ability to perform both a motor and a cognitive task simultaneously. The main aim of the current study was to evaluate the impact of performing a simultaneous cognitive task in the gait pattern of women with FM.

METHODS

A total of 36 women recruited from a local association took part in this cross-sectional study. The time required to complete the 10-meters-walking-test and kinematic outcomes including number of steps, cadence, trunk tilt and ranges of motion were analyzed under single (motor task only) and dual task (motor and cognitive tasks simultaneously) conditions. The secondary task consisted in counting aloud backward in rows of two.

RESULTS

Results showed a significant increment in the time required to complete the test (p < 0.01) when participants performed the motor and cognitive tasks at the same time. Moreover, relevant changes in kinematic parameters such as increment of number of steps (p < 0.01), cadence (p < 0.01), trunk tilt (p < 0.01) and both hip (p < 0.01) and knee (p = 0.03) ranges of motion were also observed.

CONCLUSION

Adding a cognitive task to a primary motor task affects the walking motor pattern in women with FM, making it more stable and safer walking pattern when the attention is focused on two simultaneous tasks.

Dual-Task Tests Predict Conversion to Dementia-A Prospective Memory-Clinic-Based Cohort Study

The aim of this study was to investigate whether Timed Up-and-Go (TUG) dual-task (TUGdt) tests predict dementia incidence among patients with subjective or mild cognitive impairment (SCI; MCI). Other study objectives were to determine whether TUGdt improves dementia prediction compared to a) demographic characteristics and standard cognitive tests alone; and b) TUG and Verbal Fluency performed separately. Patients (n = 172, age range 39–91 years, 78 women) with SCI or MCI performed TUGdt tests, including 1) naming animals and 2) reciting months backwards, and clinical cognitive tests at baseline. Diagnoses were identified at follow-up after 2.5 years. Logistic regression was used to predict dementia incidence, receiver operating characteristic (ROC) curves and c-statistics for predictive capacity. Analyses were stratified by age and gender. At follow-up, 51 patients had developed dementia. The TUGdt result “animals/10 s” was associated with dementia incidence (standardized odds ratio (OR) = 4.06, 95% confidence interval (CI) 2.28–7.23, p < 0.001), more so among patients under the median age of 72 years (standardized OR = 19.4, 95% CI 3.53–106.17, p < 0.001). TUGdt “animals/10 s” improved dementia prediction compared to demographic characteristics and standard tests alone (c-statistics 0.88 to 0.94) and single-task tests (c-statistics 0.86 to 0.89), but only in the younger patient group. TUGdt has the potential to become a useful tool for dementia prediction.

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

Background

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

Methods

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

Results

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

Conclusions

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

Characterizing cognitive-motor impairments in patients with myotonic dystrophy type 1

Myotonic Dystrophy Type 1 (DM1) is the most frequent hereditary, adult-onset muscular dystrophy. Nevertheless, DM1-associated cognitive-motor impairments have not been fully characterized so far. This study aimed at profiling cognitive and locomotor dysfunctions in these patients. In addition, cognitive-motor interactions were assessed using a dual-task paradigm. Comprehensive cognitive-motor impairment profiles were generated for 19 patients with DM1 and 19 healthy subjects by thorough clinical, biomechanical and neuropsychological examinations. Detailed gait analysis was performed using a 3D motion capture system, whereas cognitive function was assessed using a standardized neuropsychological test battery. Patients with DM1 showed impaired functional mobility, gait velocity and endurance. DM1-related gait pathology was mainly characterized by enhanced dynamic instability, gait variability, and restricted ankle dorsiflexion. Patients' cognitive impairments particularly concerned attentional functions. Dual-task conditions induced gait deviations that slightly differed between patients and controls. DM1-associated cognitive impairments correlated with reduced functional mobility and impaired ankle dorsiflexion. Patients with DM1 revealed significant impairments of walking function, balance and cognitive performance. Differential cognitive-motor interference and significant interactions between cognitive and motor dysfunctions point towards a prominent role of cognition in gait performance of patients with DM1.

Motor-cognitive dual-task performance of older women evaluated using Wii Balance Board

BACKGROUND

Single- and dual-tasks are influenced by age-related impaired postural balance. Aim of this study was to analyze the Center of Pressure (CoP) oscillation during static balance in the presence or absence of cognitive task on older women.

METHODS

Thirty-one healthy older women were assessed in a stand quiet position with open/closed eyes (single-task, OE and CE) and with cognitive task (dual-task, DT) through Wii Balance Board. Sway area, total displacement and CoP oscillation (CO) based on the number of times that CoP traveled through anteroposterior and mediolateral directions. Friedman test was used to compare OE, CE and DT. Dual-task interference percentage was used to quantify the cognitive load on balance whereas Spearman correlation coefficient was used to assess the association of cognitive domains and CO.

RESULTS

The CO was significantly higher in DT than in single-tasks and participants were unable to maintain their limits of stability in mediolateral direction. The cost of DT interference was 30.5%, which is partially explained by the deviation of attention from postural control to spatial and temporal orientation.

CONCLUSION

Our findings show that cognitive load during DT impairs balance in mediolateral direction, thus indicating the use of WBB to assess cognitive interference on postural control.

Brain volumes and dual-task performance correlates among individuals with cognitive impairment: a retrospective analysis

Cognitive impairment (CI) is a prevalent condition characterized by loss of brain volume and changes in cognition, motor function, and dual-tasking ability. To examine associations between brain volumes, dual-task performance, and gait and balance in those with CI to elucidate the mechanisms underlying loss of function. We performed a retrospective analysis of medical records of patients with CI and compared brain volumes, dual-task performance, and measures of gait and balance. Greater cognitive and combined dual-task effects (DTE) are associated with smaller brain volumes. In contrast, motor DTE is not associated with distinct pattern of brain volumes. As brain volumes decrease, dual-task performance becomes more motor prioritized. Cognitive DTE is more strongly associated with decreased performance on measures of gait and balance than motor DTE. Decreased gait and balance performance are also associated with increased motor task prioritization. Cognitive DTE appears to be more strongly associated with decreased automaticity and gait and balance ability than motor DTE and should be utilized as a clinical and research outcome measure in this population. The increased motor task prioritization associated with decreased brain volume and function indicates a potential for accommodative strategies to maximize function in those with CI. Counterintuitive correlations between motor brain volumes and motor DTE in our study suggest a complicated interaction between brain pathology and function.

Timed Up-and-Go Dual-Task Testing in the Assessment of Cognitive Function: A Mixed Methods Observational Study for Development of the UDDGait Protocol

New methods to screen for and identify early-stage dementia disorders are highly sought after. The purpose of this pilot study is to develop a study protocol for a dual-task test aimed at aiding the early detection of dementia disorders. We used the Timed Up-and-Go (TUG) test, which is a mobility task involving starting in a sitting position, standing up, walking three meters to cross a line on the floor, turning around, walking back and sitting down again. We combined TUG with the verbal task of naming different animals. Pilot study participants were 43 individuals with and without established dementia diagnoses who attended a clinic for memory assessment. Video-recorded test performances were systematically analysed. Deviant test performances concerning the interplay between test administration and participants' responses to the assessment instructions were revealed and led to refinements being made to the final study protocol. Exploration of the dual-task test outcome measures in a sub-sample of 22 persons, ten with and twelve without dementia, indicated that step-length and number of named animals after the turning point of the dual-task test might constitute appropriate measures for examining this kind of sample. We concluded that the refined study protocol is feasible for testing individuals undergoing initial memory assessments and healthy controls. Follow-up studies with larger samples are being carried out and will bring new knowledge to this area of research. It may also provide an opportunity for further studies exploring possibilities for broad clinical implementation.

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.

Using a dual-task paradigm to investigate motor and cognitive performance in children with intellectual disability

BACKGROUND

The purpose of the current study was to evaluate the effects of dual-task (DT) constraints on walking performance in children with intellectual disability (ID).

METHODS

Fifteen children with intellectual disability and fifteen age-matched typically developed children were asked to walk at a preferred speed: along a path (baseline condition), while carrying a glass of water and while quoting animal names.

RESULTS

The present study findings showed that DTs affect walking performance of both typically developed children and those with intellectual disability. In children with intellectual disability, DT walking decrements were significantly higher when performing a concurrent motor task than cognitive one.

CONCLUSIONS

DT constraints with a secondary motor or cognitive tasks seemed challenging for children with intellectual disability suggesting that future treatments or assessments should consider using DT constraints to manipulate the difficulty of tasks.

Impact of adding a simultaneous cognitive task in the elbow's range of movement during arm curl test in women with fibromyalgia

BACKGROUND

Fibromyalgia symptoms cause a significant reduction in the ability to perform daily life activities. These activities require the ability to perform more than one task simultaneously. The main objective of this study was to evaluate how dual-task could modify range of movement, duration of repetitions and performance in the arm curl test in healthy controls and patients with fibromyalgia.

METHODS

Twenty women participated in this study, divided into two groups: 1) patients with fibromyalgia (N = 10, age = 52.00 [5.08]) and 2) age- and gender-matched healthy controls (N = 10; age = 51.60 [4.09]). The participants had to perform the arm curl test in two conditions: single test condition and performing a dual-task. The dual-task condition consisted of remembering three random unrelated words.

RESULTS

Patients with fibromyalgia completed fewer repetitions than controls during dual-task condition (p-value = 0.015). Furthermore, both groups showed a significant decrease in the range of movement in the dual-task condition when comparing the mean of the three first repetitions with the three last ones (p-value < 0.05).

INTERPRETATION

The motor task might be prioritized over the cognitive task at the beginning of the test. However, at the end of the test, the cognitive task could require more attention due to the increased time since the words were heard, and also the motor task could require less attention after some repetitions have been performed. Thus, the addition of a cognitive task could lead to a less conscious execution of the motor task at the end of the test, which may be consistent with a reduced range of movement.

Comprehensive Quantitative Spatiotemporal Gait Analysis Identifies Gait Characteristics for Early Dementia Subtyping in Community Dwelling Older Adults

Background: Recent studies associated gait patterns with cognitive impairment stages. The current study examined the relation between dementia type and spatiotemporal gait characteristics under different walking conditions in pre and mild neurocognitive disorder stage.

Methods: Community-dwelling older adults (age 50+) with memory complaints consulting a memory clinic underwent, at baseline and during follow-up (every 4 months), a standard dementia assessment and a comprehensive spatiotemporal gait analysis [walking on an electronic walkway at usual pace (UP) with and without a counting-backwards (CW) or animal-reciting dual-task (AW), at fast (FP) and at slow (SP) pace]. At baseline the participants were categorized according to the Clinical Dementia Rating (CDR) scale. At the end of the study, the dementia diagnosis was used to stratify the categories in three outcome groups: developed “No-dementia,” “AD+FTD” (grouping Alzheimer's or Fronto-temporal dementia) or “VascD+LBD” dementia (grouping Vascular dementia or Lewy body dementia). The gait characteristics were compared per category in paired groups. Sub-analyzing in the ≥70-years-old participants evaluated the age effect.

Results: Five hundred and thirty-six participants, age 50-to-95-years old were followed for 31-to-41 months. In the CDR 0, no differences were seen between eventual dementia and no-dementia individuals. In the CDR 0.5, CW dual task cost (DTC) step width was larger in the imminent “AD+FTD” and AW (normalized) gait speed was slower in the future “VascD+LBD” group compared to the no-dementia participants. Slower UP (normalized) gait speed differed the future “VascD+LBD” from the “AD+FTD” individuals. In the CDR 1: Wider steps in UP, SP and CW differed the “VascD+LBD” from the “AD+FTD” group. In the ≥70-years old CDR 0 category, higher AW cycle time variability in the imminent “AD+FTD” dementia group, wider UP step width and higher AW cycle time variability in the “VascD+LBD” group differed them from the no-dementia group up to 3 years before dementia diagnosis. The distinctive gait characteristics between the no-dementia and the imminent dementia groups in CDR 0.5 and CDR 1 remained the same as in the overall group. However, no gait differences were found between “VascD+LBD” and “AD+FTD” groups in the pre-dementia stages.

Conclusion: Distinctive spatiotemporal gait characteristics were associated with specific dementia types up to 3 years before diagnosis. The association is influenced by the cognitive stage and age.

Non-dominant hand use increases completion time on part B of the Trail Making Test but not on part A

The Trail Making Test (TMT) is used in neuropsychological clinical practice to assess aspects of attention and executive function. The test consists of two parts (A and B) and requires drawing a trail between elements. Many patients are assessed with their non-dominant hand because of motor dysfunction that prevents them from using their dominant hand. Since drawing with the non-dominant hand is not an automatic task for many people, we explored the effect of hand use on TMT performance. The TMT was administered digitally in order to analyze new outcome measures in addition to total completion time. In a sample of 82 healthy participants, we found that non-dominant hand use increased completion times on the TMT B but not on the TMT A. The average completion time increased by almost 5 seconds, which may be clinically relevant. A substantial number of participants who performed the TMT with their non-dominant hand had a B/A ratio score of 2.5 or higher. In clinical practice, an abnormally high B/A ratio score may be falsely attributed to cognitive dysfunction. With our digitized pen data, we further explored the causes of the reduced TMT B performance by using new outcome measures, including individual element completion times and interelement variability. These measures indicated selective interference between non-dominant hand use and executive functions. Both non-dominant hand use and performance of the TMT B seem to draw on the same, limited higher-order cognitive resources.

Spatiotemporal gait analysis of older persons in clinical practice and research : Which parameters are relevant?

For older persons walking is a basic activity of daily life which characterizes the person's functional mobility. Therefore, the improvement of walking performance is a major clinical outcome during geriatric rehabilitation. Furthermore, walking performance is relevant for several geriatric research issues. Quantitative gait analysis can describe walking performance in detail. Besides gait speed, various qualitative parameters related to different aspects of walking performance, such as symmetry, regularity, coordination, dynamic balance and foot movement during the swing phase, can serve as outcome parameters in geriatric research and in clinical practice. Clinicians and researchers have to decide which parameters are appropriate to be used as relevant outcome parameters in the investigated person or group of persons.

Dementia

Dementia is a syndrome seen most commonly in older people and characterized by a decline in cognitive performance which impacts on the person's ability to function. There are approximately 47 million people worldwide with dementia and there are 10 million new cases every year. It is a major cause of disability and dependence and impacts on the physical, psychologic, and social well-being of families and carers. Alzheimer's disease is the most common form of dementia. Gait and balance impairments are common in people with dementia and contribute to the significantly elevated risk of falls. Older people with dementia are at increased risk of injury, institutionalization, hospitalization, morbidity, and death after a fall. There is preliminary evidence, predominantly from relatively small studies, that falls and disability can be prevented in this population. However, more good-quality research is needed, both to provide some certainty around the existing evidence base as well as to explore alternate approaches to prevention, including combined cognitive-motor training and cognitive pharmacotherapy.

Role of impaired vision during dual-task walking in young and older adults

While cognitive-motor interference in dual-task activities is well established, it is still unknown how such interference is influenced by concurrent visual challenges. Nineteen community-dwelling healthy, cognitively intact, older adults (Mean±SD=71.45±1.25years, 6 males) and nineteen young adults (Mean±SD=22.25±0.68years, 4 males) performed a cognitive-single-task (serial subtraction by 3), a walking-single-task and a cognitive-walking-dual-task under normal, blurred and peripheral-vision-loss conditions (artificially imposed using goggles). Gait parameters and the number of correct responses were measured. Dual task costs for both walking and cognition were computed. Results showed that higher walking cost was seen with impaired vision (p=0.05) and with older adults (p=0.03); greater cognitive cost was seen with impaired vision (p=0.01), but no difference in cognitive cost was seen between young and older adults. Thus, when faced with impaired vision, both young and older adults appear to allocate less attention to cognition than to walking, and thus prioritize walking. Future work should explore whether dual-task training under visual challenge could reduce cognitive-motor interference and reduce fall risks in older adults.

Carotid flow pulsatility is higher in women with greater decrement in gait speed during multi-tasking

AIM

Central arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT.

METHODS

Gait speed was measured using a motion capture system in 56 women (30-80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7's. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and β-stiffness index in the common carotid artery.

RESULTS

The percent change in gait speed was larger for MT than DT (14.1±11.2 vs. 8.7±9.6%, p <0.01). Tertiles were formed based on the percent change in gait speed for each condition. No vascular parameters differed across tertiles for DT. In contrast, carotid flow pulsatility (1.85±0.43 vs. 1.47±0.42, p=0.02) and resistance (0.75±0.07 vs. 0.68±0.07, p=0.01) indices were higher in women with more decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and β-stiffness did not contribute to these tertile differences.

CONCLUSION

Elevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks.

Impact of cognitive fatigue on gait and sway among older adults: A literature review

Cognitive fatigue is an alteration in central nervous system (CNS) processing due to prolonged performance of mentally demanding tasks. Decreased gait speed and increased stride length variability have been noted in cognitively fatigued older adults (≥ 65 years). Further, cognitive fatigue may weaken the visual, vestibular, and proprioceptive systems of the CNS, contributing to increased postural sway. Detriments in gait and sway caused by cognitive fatigue could increase fall risk. The objective of this literature review was to evaluate the impact of cognitive fatigue on changes in gait and postural sway and its role in fall risk.

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Cognitive fatigue may cause gait disturbances in older adults (≥ 65 years).

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Cognitive fatigue may increase postural sway in older adults.

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Cognitive fatigue may be considered a fall risk for older adults.

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Interventions to attenuate cognitive fatigue should be further explored.

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Studies should explore the role of cognitive fatigue in fall risk.

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.

Dizziness and Unstable Gait in Old Age: Etiology, Diagnosis and Treatment

BACKGROUND

Dizziness and unsteady gait are common in the elderly but are too often dismissed as supposedly nonspecific, inevitable accompaniments of normal aging. For many affected persons, the factors leading to dizziness and gait impairment in old age are never identified, yet some of these factors can be specifically detected and treated.

METHODS

This review is based on publications (2005-2014) retrieved by a selective search in PubMed on the terms "aging," "dizziness," "elderly," "gait," "gait disorder," "geriatric," "locomotion," and "vertigo."

RESULTS

Dizziness interferes with the everyday activities of 30% of persons over age 70 and is so severe that it constitutes a reason for consulting a physician. The more common causes of dizziness and unsteady gait in old age are sensory deficits, such as bilateral vestibular failure, polyneuropathy, and impaired visual acuity; benign paroxysmal positioning vertigo; and central disorders such as cerebellar ataxia and normal-pressure hydrocephalus. Further relevant factors include sedative or antihypertensive medication, loss of muscle mass (sarcopenia), and fear of falling. Many elderly persons have multiple factors at the same time. Benign paroxysmal positioning vertigo can be effectively treated with specific physical maneuvers. Sedating drugs are indicated only for the treatment of acute rotatory vertigo and are not suitable for long-term use. Sarcopenia can be treated with physical training.

CONCLUSION

If a specific cause can be identified, dizziness and gait unsteadiness in old age can often be successfully treated. The common causes can be revealed by systematic clinical examination. Controlled clinical trials on the efficacy of treatments for elderly persons are urgently needed.

Cellular Telephone Dialing Influences Kinematic and Spatiotemporal Gait Parameters in Healthy Adults

Gait speed is typically reduced when individuals simultaneously perform other tasks. However, the impact of dual tasking on kinetic and kinematic gait parameters is unclear because these vary with gait speed. The objective of this study was to identify whether dual tasking impacts gait in healthy adults when speed is constant. Twenty-two healthy adults dialed a cell phone during treadmill walking at a self-selected speed while kinetic, kinematic, and spatial parameters were recorded. Results indicated that dual tasking did not impact phone dialing speed, but increased stride width, peak knee flexion during stance, and peak plantarflexion, and decreased knee and ankle range of motion. Dual tasking appears to influence kinematic gait variables in a manner consistent with promotion of stability.

Temporal and spatial gait parameters in children with Cri du Chat Syndrome under single and dual task conditions

AIM

To describe temporal and spatial gait characteristics in individuals with Cri du Chat syndrome (CdCS) and to explore the effects of performing concurrent manual tasks while walking.

METHODS

The gait parameters of 14 participants with CdCS (mean age 10.3, range 3-20 years) and 14 age-matched controls (mean age 10.1, range 3-20 years) were collected using the GAITRite^® instrumented walkway. All participants first walked without any concurrent tasks and then performed 2 motor dual task walking conditions (pitcher and tray).

RESULTS

Individuals with CdCS took more frequent, smaller steps than controls, but, on average, had a comparable gait speed. In addition, there was a significant task by group interaction. Participants decreased gait speed, decreased cadence, decreased step length, and increased% time in double limb support under dual task conditions compared to single task conditions. However, the age-matched controls altered their gait for both manual tasks, and the participants with CdCS only altered their gait for the tray task.

INTERPRETATION

Although individuals with CdCS ambulate with a comparable gait speed to age-matched controls under single task conditions, they did not significantly alter their gait when carrying a pitcher with a cup of water inside, like controls. It is not clear whether or not individuals with CdCS had difficulty attending to task demands or had difficulty modifying their gait.

Reducing falls in Parkinson's disease: interactions between donepezil and the 5-HT6 receptor antagonist idalopirdine on falls in a rat model of impaired cognitive control of complex movements

Falls are a leading cause of death in the elderly and, in a majority of patients with Parkinson's disease (PD), the leading levodopa-insensitive cause of hospitalization and long-term care. Falling in PD has been attributed to degeneration of forebrain cholinergic neurons that, in interaction with striatal dopamine losses, impairs the cognitive control of balance, gait, and movement. We previously established an animal model of these dual cholinergic-dopaminergic losses ("DL rats") and a behavioral test system (Michigan Complex Motor Control Task, MCMCT) to measure falls associated with traversing dynamic surfaces and distractors. Because the combined treatment of the acetylcholinesterase inhibitor donepezil and the 5-HT₆ receptor antagonist idalopirdine (Lu AE58054) was reported to exhibit synergistic pro-cholinergic activity in rats and improved cognition in patients with moderate Alzheimer's disease, here we assessed the effects of this treatment on MCMCT performance and attention in DL rats. Compared with the vehicle-treated group, the combined treatment greatly reduced (Cohen's d = 0.96) falls in DL rats when traversing dynamic surfaces and when exposed to a passive distractor. However, falls associated with a dual task distractor and sustained attentional performance did not benefit from this treatment. Analyses of the behavior in fall-prone moments suggested that this treatment improved the efficacy and speed of re-instating forward movement after relatively short stoppages. This treatment may reduce fall propensity in PD patients via maintaining planned movement sequences in working memory and improving the vigor of executing such movements following brief periods of freezing of gait.

The Effect of Two Different Cognitive Tests on Gait Parameters during Dual Tasks in Healthy Postmenopausal Women

INTRODUCTION

The paper aims to evaluate the influence of two different demanding cognitive tasks on gait parameters using BTS SMART system analysis.

PATIENTS AND METHODS

The study comprised 53 postmenopausal women aged 64.5 ± 6.7 years (range: 47-79). For every subject, gait analysis using a BTS SMART system was performed in a dual-task study design under three conditions: (I) while walking only (single task), (II) walking while performing a simultaneous simple cognitive task (SCT) (dual task), and (III) walking while performing a simultaneous complex cognitive task (CCT) (dual task). Time-space parameters of gait pertaining to the length of a single support phase, double support phase, gait speed, step length, step width, and leg swing speed were analyzed.

RESULTS

Performance of cognitive tests during gait resulted in a statistically significant prolongation of the left (by 7%) and right (by 7%) foot gait cycle, shortening of the length of steps made with the right extremity (by 4%), reduction of speed of swings made with the left (by 11%) and right (by 8%) extremity, and reduction in gait speed (by 6%).

CONCLUSIONS

Performance of cognitive tests during gait changes its individual pattern in relation to the level of the difficulty of the task.

Coaching or gaming? Implications of strategy choice for home based stroke rehabilitation

Background

The enduring aging of the world population and prospective increase of age-related chronic diseases urge the implementation of new models for healthcare delivery. One strategy relies on ICT (Information and Communications Technology) home-based solutions allowing clients to pursue their treatments without institutionalization. Stroke survivors are a particular population that could strongly benefit from such solutions, but is not yet clear what the best approach is for bringing forth an adequate and sustainable usage of home-based rehabilitation systems. Here we explore two possible approaches: coaching and gaming.

Methods

We performed trials with 20 healthy participants and 5 chronic stroke survivors to study and compare execution of an elbow flexion and extension task when performed within a coaching mode that provides encouragement or within a gaming mode. For each mode we analyzed compliance, arm movement kinematics and task scores. In addition, we assessed the usability and acceptance of the proposed modes through a customized self-report questionnaire.

Results

In the healthy participants sample, 13/20 preferred the gaming mode and rated it as being significantly more fun (p < .05), but the feedback delivered by the coaching mode was subjectively perceived as being more useful (p < .01). In addition, the activity level (number of repetitions and total movement of the end effector) was significantly higher (p < .001) during coaching. However, the quality of movements was superior in gaming with a trend towards shorter movement duration (p = .074), significantly shorter travel distance (p < .001), higher movement efficiency (p < .001) and higher performance scores (p < .001). Stroke survivors also showed a trend towards higher activity levels in coaching, but with more movement quality during gaming. Finally, both training modes showed overall high acceptance.

Conclusions

Gaming led to higher enjoyment and increased quality in movement execution in healthy participants. However, we observed that game mechanics strongly determined user behavior and limited activity levels. In contrast, coaching generated higher activity levels. Hence, the purpose of treatment and profile of end-users has to be considered when deciding on the most adequate approach for home based stroke rehabilitation.

[Effects of cognitive state on balance disturbances and gait disorders in institutionalised elderly]

BACKGROUND

Ageing has been linked to a high prevalence of cognitive impairment, which, in turn, has been related to balance disturbances and gait disorders. The aim of this study was to identify whether there are differences between subjects with and without cognitive impairment regarding the quality of gait and balance.

MATERIAL AND METHODS

An observational study was conducted on institutionalised people older than 65 years (n=82). Gait and balance was evaluated after the assessment of cognitive impairment using the Mini-Mental State Examination (MMSE). Single and dual tests were used including, the 6-minute walking, stride length, and gait speed. Timed Up and Go tests were also used to evaluate balance.

RESULTS

The participants were divided into three groups: 28 subjects in the group without cognitive impairment (MMSE≥27), 29 subjects with mild (27<MMSE≤21) and 26 subjects with moderate cognitive impairment (MMSE<21). Gait assessment showed significant between-groups differences in all the variables (P<.05). The variables assessing balance also showed significantly worse values in those groups with cognitive impairment.

CONCLUSION

The severity of cognitive impairment is related to impaired balance and gait, thus the clinical monitoring of these variables in population at risk is needed.

Oscillations in the human brain during walking execution, imagination and observation

Gait is an essential human activity which organizes many functional and cognitive behaviors. The biomechanical constraints of bipedalism implicating a permanent control of balance during gait are taken into account by a complex dialog between the cortical, subcortical and spinal networks. This networking is largely based on oscillatory coding, including changes in spectral power and phase-locking of ongoing neural activity in theta, alpha, beta and gamma frequency bands. This coding is specifically modulated in actual gait execution and representation, as well as in contexts of gait observation or imagination. A main challenge in integrative neuroscience oscillatory activity analysis is to disentangle the brain oscillations devoted to gait control. In addition to neuroimaging approaches, which have highlighted the structural components of an extended network, dynamic high-density EEG gives non-invasive access to functioning of this network. Here we revisit the neurophysiological foundations of behavior-related EEG in the light of current neuropsychological theoretic frameworks. We review different EEG rhythms emerging in the most informative paradigms relating to human gait and implications for rehabilitation strategies.

The aging brain shows less flexible reallocation of cognitive resources during dual-task walking: A mobile brain/body imaging (MoBI) study

Aging is associated with reduced abilities to selectively allocate attention across multiple domains. This may be particularly problematic during everyday multitasking situations when cognitively demanding tasks are performed while walking. Due to previous limitations in neuroimaging technology, much remains unknown about the cortical mechanisms underlying resource allocation during locomotion. Here, we utilized an EEG-based mobile brain/body imaging (MoBI) technique that integrates high-density event-related potential (ERP) recordings with simultaneously acquired foot-force sensor data to monitor gait patterns and brain activity concurrently. To assess effects of motor load on cognition we evaluated young (N=17; mean age=27.2) and older adults (N=16; mean age=63.9) and compared behavioral and ERP measures associated with performing a Go/No-Go response inhibition task as participants sat stationary or walked on a treadmill. Stride time and variability were also measured during task performance and compared to stride parameters obtained without task performance, thereby assessing effects of cognitive load on gait. Results showed that older, but not young adults' accuracy dropped significantly when performing the inhibitory task while walking. Young adults revealed ERP modulations at relatively early (N2 amplitude reduction) and later (earlier P3 latency) stages within the processing stream as motor load increased while walking. In contrast, older adults' ERP modulations were limited to later processing stages (increased P3 amplitude) of the inhibitory network. The relative delay and attenuation of ERP modulations accompanied by behavioral costs in older participants might indicate an age-associated loss in flexible resource allocation across multiple tasks. Better understanding of the neural underpinnings of these age-related changes may lead to improved strategies to reduce fall risk and enhance mobility in aging.

The relationship between dual-task and cognitive performance among elderly participants who exercise regularly

BACKGROUND:

The dual-task performance is associated with the functionality of the elderly and it becomes more complex with age.

OBJECTIVE:

To investigate the relationship between the Timed Up and Go dual task (TUG-DT) and cognitive tests among elderly participants who exercise regularly.

METHOD:

This study examined 98 non-institutionalized people over 60 years old who exercised regularly. Participants were assessed using the TUG-DT (i.e. doing the TUG while listing the days of the week in reverse order), the Montreal Cognitive Assessment (MoCA), the Clock Drawing Test (CDT), and the Mini Mental State Examination (MMSE). The motor (i.e. time and number of steps) and cognitive (i.e. number of correct words) data were collected from TUG-DT . We used a significance level of α=0.05 and SPSS 17.0 for all data analyses.

RESULTS:

This current elderly sample featured a predominance of women (69.4%) who were highly educated (median=10 years of education) compared to Brazilian population and mostly non-fallers (86.7%). The volunteers showed a good performance on the TUG-DT and the other cognitive tests, except the MoCA, with scores below the cutoff of 26 points. Significant and weak correlations were observed between the TUG-DT (time) and the visuo-spatial/executive domain of the MoCA and the MMSE. The cognitive component of the TUG-DT showed strong correlations between the total MoCA performance score and its visuo-spatial/executive domain.

CONCLUSIONS:

The use of the TUG-DT to assess cognition is promising; however, the use of more challenging cognitive tasks should be considered when the study population has a high level of education.

Reliability of a novel serious game using dual-task gait profiles to early characterize aMCI

Background: As the population of older adults is growing, the interest in a simple way to detect characterize amnestic mild cognitive impairment (aMCI), a prodromal stage of Alzheimer’s disease (AD), is becoming increasingly important. Serious game (SG) -based cognitive and motor performance profiles while performing everyday activities and dual-task walking (DTW) “motor signatures” are two very promising markers that can be detected in predementia states. We aim to compare the consistency, or conformity, of measurements made by a custom SG with DTW (NAV), a SG without DTW (DOT), neuropsychological measures and genotyping as markers for early detection of aMCI.

Methods: The study population included three groups: early AD (n = 86), aMCI (n = 65), and healthy control subjects (n = 76), who completed the custom SG tasks in three separate sessions over a 3-month period. Outcome measures were neuropsychological data across-domain and within-domain intra-individual variability (IIV) and DOT and NAV latency-based and accuracy-based IIV. IIV reflects a transient, within-person change in behavioral performance, either during different cognitive domains (across-domain) or within the same domain (within-domain). Test–retest reliability of the DOT and NAV markers were assessed using an intraclass correlation (ICC) analysis.

Results: Results indicated that performance data, such as the NAV latency-based and accuracy-based IIV, during the task displayed greater reliability across sessions compared to DOT. During the NAV task-engagement, the executive function, planning, and motor performance profiles exhibited moderate to good reliability (ICC = 0.6–0.8), while during DOT, executive function and spatial memory accuracy profiles exhibited fair to moderate reliability (ICC = 0.3–0.6). Additionally, reliability across tasks was more stable when three sessions were used in the ICC calculation relative to two sessions.

Discussion: Our findings suggest that “motor signature” data during the NAV tasks were a more reliable marker for early diagnosis of aMCI than DOT. This result accentuates the importance of utilizing motor performance data as a metric for aMCI populations where memory decline is often the behavioral outcome of interest. In conclusion, custom SG with DTW performance data provide an ecological and reliable approach for cognitive assessment across multiple sessions and thus can be used as a useful tool for tracking longitudinal change in observational and interventional studies on aMCI.