Walking Task Research Articles

Step and Distance Measurement From a Low-Cost Consumer-Based Hip and Wrist Activity Monitor: Protocol for a Validity and Reliability Assessment.

BackgroundSelf-tracking via wearable and mobile technologies is becoming an essential part of personal health management. At this point, however, little information is available to substantiate the validity and reliability of low-cost consumer-based hip and wrist activity monitors, with regard more specifically to the measurements of step counts and distance traveled while walking.ObjectiveThe aim of our study is to assess the validity and reliability of step and distance measurement from a low-cost consumer-based hip and wrist activity monitor specific in various walking conditions that are commonly encountered in daily life. Specifically, this study is designed to evaluate whether and to what extent validity and reliability could depend on the sensor placement on the human body and the walking task being performed.MethodsThirty healthy participants will be instructed to wear four PBN 2433 (Nakosite) activity monitors simultaneously, with one placed on each hip and each wrist. Participants will attend two experimental sessions separated by 1 week. During each experimental session, two separate studies will be performed. In study 1, participants will be instructed to complete a 2-minute walk test along a 30-meter indoor corridor under 3 walking speeds: very slow, slow, and usual speed. In study 2, participants will be required to complete the following 3 conditions performed at usual walking speed: walking on flat ground, upstairs, and downstairs. Activity monitor measured step count and distance values will be computed along with the actual step count (determined from video recordings) and distance (measured using a measuring tape) to determine validity and reliability for each activity monitor placement and each walking condition.ResultsParticipant recruitment and data collection began in January 2020. As of June 2020, we enrolled 8 participants. Dissemination of study results in peer-reviewed journals is expected in spring 2021.ConclusionsTo the best of our knowledge, this is the first study that examines the validity and reliability of step and distance measurement during walking using the PBN 2433 (Nakosite) activity monitor. Results of this study will provide beneficial information on the effects of activity monitor placement, walking speed, and walking tasks on the validity and reliability of step and distance measurement. We believe such information is of utmost importance to general consumers, clinicians, and researchers.International Registered Report Identifier (IRRID)DERR1-10.2196/21262

How aging affects visuomotor adaptation and retention in a precision walking paradigm

Motor learning is a lifelong process. However, age-related changes to musculoskeletal and sensory systems alter the relationship (or mapping) between sensory input and motor output, and thus potentially affect motor learning. Here we asked whether age affects the ability to adapt to and retain a novel visuomotor mapping learned during overground walking. We divided participants into one of three groups (n = 12 each) based on chronological age: a younger-aged group (20–39 years old); a middle-aged group (40–59 years old); and an older-aged group (60–80 years old). Participants learned a new visuomotor mapping, induced by prism lenses, during a precision walking task. We assessed retention one-week later. We did not detect significant effects of age on measures of adaptation or savings (defined as faster relearning). However, we found that older adults demonstrated reduced initial recall of the mapping, reflected by greater foot-placement error during the first adaptation trial one-week later. Additionally, we found that increased age significantly associated with reduced initial recall. Overall, our results suggest that aging does not impair adaptation and that older adults can demonstrate visuomotor savings. However, older adults require some initial context during relearning to recall the appropriate mapping.

Lightening the Perceived Prosthesis Weight with Neural Embodiment Promoted by Sensory Feedback

One of the main reasons why amputees report poor satisfaction with prostheses is their excessive weight perceived,1 despite the fact that they typically weigh less than half of the natural limb.2 Weight perception can be a subjective percept that is influenced by cognitive processes.3-5 Even though recent developments in prosthetics have shown that sensory feedback restoration positively influences cognitive aspects (as embodiment of the device and cognitive load),6,7 the potential benefits on prosthesis heaviness perception have never been investigated. In this study, we explored this matter using intraneural sensory feedback in a transfemoral (above-knee) amputee. We hypothesized that providing neural feedback would affect the integration of the prosthesis in the amputee's body schema, hence influencing the prosthesis weight perception. The results indicate that, after performing an over-ground walking task, the sensory feedback allowed a 23% decrease in prosthesis heaviness perception compared to the no feedback condition. Our hypothesis was confirmed by a significant increase in the embodiment of the prosthesis (by 60.5%) and confidence (by 36%) while walking with the sensory feedback. A subsequent dual task (i.e., walking while spelling backward) showed that the sensory feedback abolished the reduction of walking speed and accuracy observed during the no-feedback condition and normally seen with increased mental workload, suggesting a cognitive integration of the system. These results show the importance of providing close-to-natural sensations from the missing limb to allow a good integration of the prostheses and increase the satisfaction of their users. VIDEO ABSTRACT.

Brain activity of the emotional circuit in Parkinson’s disease patients with freezing of gait

ObjectiveEmotional processes might influence freezing of gait (FoG) in Parkinson’s disease (PD) patients. We assessed brain functional MRI (fMRI) activity during a “FoG-observation-task” in PD-FoG patients relative to healthy controls. MethodsTwenty-four PD-FoG patients and 18 age- and sex-matched healthy controls performed clinical and neuropsychological evaluations, and fMRI experiments including: i) “FoG-observation-task” consisting of watching a patient experiencing FoG during a walking task (usually evoking FoG); ii) “gait-observation-task” consisting of watching a healthy subject performing similar walking tasks without experiencing FoG. ResultsDuring both tasks, PD-FoG patients showed reduced activity of the fronto-parietal mirror neuron system (MNS) relative to controls. In the “FoG-observation-task” relative to the “gait-observation-task”, PD-FoG patients revealed an increased recruitment of the anterior medial prefrontal cortex and a reduced recruitment of the dorsomedial prefrontal cortex and hippocampus relative to controls. Healthy controls in the “FoG-observation-task” relative to the “gait-observation-task” showed increased recruitment of cognitive empathy areas and decreased activity of the fronto-parietal MNS. ConclusionOur results suggest that when PD-FoG patients observe a subject experiencing FoG, there is an increased activity of brain areas involved in self-reflection emotional processes and a reduced activity of areas related to motor programming, executive functions and cognitive empathy. These findings support previous evidence on the critical role of the emotional circuit in the mechanisms underlying FoG.

Chronic Pain is Associated With Reduced Sympathetic Nervous System Reactivity During Simple and Complex Walking Tasks: Potential Cerebral Mechanisms

Background Autonomic dysregulation may lead to blunted sympathetic reactivity in chronic pain states. Autonomic responses are controlled by the central autonomic network (CAN). Little research has examined sympathetic reactivity and associations with brain CAN structures in the presence of chronic pain; thus, the present study aims to investigate how chronic pain influences sympathetic reactivity and associations with CAN brain region volumes. Methods Sympathetic reactivity was measured as change in skin conductance level (ΔSCL) between a resting reference period and walking periods for typical and complex walking tasks (obstacle and dual-task). Participants included 31 people with (n = 19) and without (n = 12) chronic musculoskeletal pain. Structural 3 T MRI was used to determine gray matter volume associations with ΔSCL in regions of the CAN (i.e., brainstem, amygdala, insula, and anterior cingulate cortex). Results ΔSCL varied across walking tasks (main effect p = 0.036), with lower ΔSCL in chronic pain participants compared to controls across trials 2 and 3 under the obstacle walking condition. ΔSCL during typical walking was associated with multiple CAN gray matter volumes, including brainstem, bilateral insula, amygdala, and right caudal anterior cingulate cortex (p’s < 0.05). The difference in ΔSCL from typical-to-obstacle walking were associated with volumes of the midbrain segment of the brainstem and anterior segment of the circular sulcus of the insula (p’s < 0.05), with no other significant associations. The difference in ΔSCL from typical-to-dual task walking was associated with the bilateral caudal anterior cingulate cortex, and left rostral cingulate cortex (p’s < 0.05). Conclusions Sympathetic reactivity is blunted during typical and complex walking tasks in persons with chronic pain. Additionally, blunted sympathetic reactivity is associated with CAN brain structure, with direction of association dependent on brain region. These results support the idea that chronic pain may negatively impact typical autonomic responses needed for walking performance via its potential impact on the brain.

Patterns of physical activity and exercise after lumbar surgery among Japanese patients with lumbar spinal stenosis.

[Purpose] The purpose of this study was to assess the feasibility of classifying the patterns of physical activity and exercise after surgery for lumbar spinal stenosis in Japanese patients and describe the characteristics of the patient groups. [Participants and Methods] We evaluated Japanese patients diagnosed as having lumbar spinal stenosis and underwent surgery. The frequencies of the 15 types of physical activity and exercise recommended in Kenko Nippon 21 (Japanese policy for health promotion) were investigated by mail. The study included 102 respondents (median age, 69 years [range, 34–88 years]; 55 males and 47 females). A hierarchical cluster analysis was used for grouping according to the physical activity and exercise patterns. The Holm method and residual analysis were used for comparisons of the frequencies of the physical activity and exercise patterns and basic demographics among the groups. [Results] Three clusters, namely clusters A (younger), B (frail older), and C (active older), were identified from the dendrogram. The participants in cluster A frequently performed paid work. In cluster B, the frequencies of all the physical activity and exercise patterns were low. The older people in cluster C regularly performed stretching/light-intensity exercises, walking, muscle-strengthening exercises, and house and garden maintenance tasks. [Conclusion] We found that the physical activity and exercise after lumbar surgery in Japanese patients could be divided into three patterns.

Magnetometer-Free, IMU-Based Foot Progression Angle Estimation for Real-Life Walking Conditions.

Foot progression angle (FPA) is vital in many disease assessment and rehabilitation applications, however previous magneto-IMU-based FPA estimation algorithms can be prone to magnetic distortion and inaccuracies after walking starts and turns. This paper presents a foot-worn IMU-based FPA estimation algorithm comprised of three key components: orientation estimation, acceleration transformation, and FPA estimation via peak foot deceleration. Twelve healthy subjects performed two walking experiments to evaluation IMU algorithm performance. The first experiment aimed to validate the proposed algorithm in continuous straight walking tasks across seven FPA gait patterns (large toe-in, medium toe-in, small toe-in, normal, small toe-out, medium toe-out, and large toe-out). The second experiment was performed to evaluate the proposed FPA algorithm for steps after walking starts and turns. Results showed that FPA estimations from the IMU-based algorithm closely followed marker-based system measurements with an overall mean absolute error of 3.1±1.3 deg, and the estimation results were valid for all steps immediately after walking starts and turns. This work could enable FPA assessment in environments where magnetic distortion is present due to ferrous metal structures and electrical equipment, or in real-life walking conditions when walking starts, stops, and turns commonly occur.

Mapping of electrodermal activity (EDA) during outdoor community-level mobility tasks in individuals with lower-limb amputation.

IntroductionBalance confidence and perception of task challenge is an important construct to measure in rehabilitation of people with lower-limb amputation (LLA). Measurement of electrodermal activity (EDA) captures physiological arousal responses reflecting an individual’s perceived challenge in a task. This study explores the feasibility of the use of EDA during outdoor walking tasks to capture task-specific physiological arousal changes associated with perception of challenge in people with amputation.ObjectiveTo develop and demonstrate feasibility of a portable EDA/GPS system mapping physiological arousal while challenging walking balance outdoors in individuals with LLA and controls.MethodsSixteen people (eight with LLA and eight age-/sex-matched controls) completed an outdoor walking course in the community (3 laps). A battery-powered portable device was developed containing EDA/GPS sensors with data logged on a microcontroller. Phasic EDA response was extracted from EDA signal to explore the physiological arousal response to walking tasks.ResultsPhysiological arousal demonstrated task-specific modulation with ascending stairs without a handrail showing higher levels of phasic EDA than walking on a paved incline (p = 0.01) or a gravel decline (p = 0.01) in people with LLA. While evidence of habituation over repeated trials was shown in controls with lap 1 of walking down a gravel decline showing higher levels of phasic EDA than lap 3 (p = 0.01). Phasic EDA maps, representative of arousal levels throughout the walking course, showed individual-specific response.ConclusionMapping of EDA during outdoor walking is feasible. Modulation of physiological arousal between outdoor walking tasks and over repeated trials is suggestive of clinical utility. Further research is warranted to explore how EDA may be incorporated into assessment of response to outdoor walking amongst individuals following LLA.

지역사회에 거주하는 만성 뇌졸중 환자들이 경험하는 보행과제에 관한 연구

This study aimed to report the walking tasks most frequently encountered in the daily life of community-dwelling patients with post-stroke hemiparesis and to compare them with those of normal adults from a previous study. A total of 97 community-dwelling ambulatory patients with chronic stroke completed a walking survey to document the frequency with which walking tasks were encountered during a full awaking, non-therapy day, which included five tasks (walking surfaces, opening/closing doors, skilled walking tasks, intersections, and steps). The results showed that the most frequently encountered task (≥10 times per day) was opening/closing doors, followed by walking on rough and smooth surfaces. Furthermore, subjects were more likely to less frequently participate in challenging tasks while walking. These findings suggest that it needs to involve walking tasks encountered by patients with chronic stroke while walking in the household and community. This study provides valuable information for future studies that try to develop a walking training protocol aiming to restore functional walking capacity for community reintegration after stroke.

Upper and Lower Limb Movement Kinematics in Aging FMR1 Gene Premutation Carriers.

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder associated with a premutation cytosine-guanine-guanine (CGG) trinucleotide repeat expansion of the FMR1 gene. FXTAS is estimated to be the most common single-gene form of ataxia in the aging population. Gait ataxia and intention tremor are the primary behavioral symptoms of FXTAS, though clinical evaluation of these symptoms often is subjective, contributing to difficulties in reliably differentiating individuals with FXTAS and asymptomatic premutation carriers. This study aimed to clarify the extent to which quantitative measures of gait and upper limb kinematics may serve as biobehavioral markers of FXTAS degeneration. Nineteen premutation carriers (aged 46–77 years), including 9 with possible, probable, or definite FXTAS and 16 sex- and IQ-matched healthy controls, completed tests of non-constrained walking and reaching while both standing (static reaching) and walking (dynamic reaching) to quantify gait and upper limb control, respectively. For the non-constrained walking task, participants wore reflective markers and walked at their preferred speed on a walkway. During the static reaching task, participants reached and lifted boxes of different sizes while standing. During the dynamic reaching task, participants walked to reach and lift the boxes. Movement kinematics were examined in relation to clinical ratings of neuromotor impairments and CGG repeat length. During non-constrained walking, individuals with FXTAS showed decreased stride lengths and stride velocities, increased percentages of double support time, and increased variabilities of cadence and center of mass relative to both asymptomatic premutation carriers and controls. While individuals with FXTAS did not show any static reaching differences relative to the other two groups, they showed multiple differences during dynamic reaching trials, including reduced maximum reaching velocity, prolonged acceleration time, and jerkier movement of the shoulder, elbow, and hand. Gait differences during non-constrained walking were associated with more severe clinically rated posture and gait symptoms. Reduced maximum reaching velocity and increased jerkiness during dynamic reaching were each related to more severe clinically rated kinetic dysfunction and overall neuromotor symptoms in FMR1 premutation carriers. Our findings suggest kinematic alterations consistent with gait ataxia and upper limb bradykinesia are each selectively present in individuals with FXTAS, but not asymptomatic aging premutation carriers. Consistent with neuropathological and magnetic resonance imaging (MRI) studies of FXTAS, these findings implicate cerebellar and basal ganglia degeneration associated with neuromotor decline. Our results showing associations between quantitative kinematic differences in FXTAS and clinical ratings suggest that objective assessments of gait and reaching behaviors may serve as critical and reliable targets for detecting FXTAS risk and monitoring progression.

Optical Sensing Approach to the Recognition of Different Types of Particulate Matters for Sustainable Indoor Environment Management

The indoor environment is a crucial part of the built environment where our daily time is mostly spent. It is governed not only by indoor activities, but also affected by interconnected activities such as door opening, walking and routine tasks throughout the inside and outside of buildings and houses. Pollutant control is one of the major concerns for maintaining a sustainable indoor environment, and finding the source of pollutants is a relatively hard part of that task. Pollutants are emitted from various sources, transformed by sunlight, react with vapor in ozone and are transported into cities and from country to country. Due to these reasons, there has been high demand to monitor the transportation of particulate matters and improve air quality. The monitoring of pollutants and identification of their type and concentration enables us to track and control their generation and consequently discover reliable suitable mitigation measures to control air quality at regulated levels by contaminant source removal. However, the monitoring of pollutants, especially particulate matter generation and its transportation, is still not fully operated in atmospheric air due to its open nature and meteorological factors. Even though indoor air is relatively easier to monitor and control than outdoor air in the aspect of specific volume and contaminant source, meteorological parameters still need to be considered because indoor air is not fully separated from outdoor air flow and contaminants’ transportation. In this study, an optical approach using a spectral sensor was attempted to reveal the feasibility of wavelength and chromaticity values of reflected light from specific particles. From the analysis of reflected light of various particulate matters according to different liquid additives, parameter studies were performed to investigate which experimental conditions can contribute to the enhanced selective sensing of particulate matter. Five different particulate matters such as household dust, soil, talc powder, gypsum powder and yellow pine tree pollen were utilized. White samples were selectively identified by the peak at 720 nm for talc and 433 nm and 690 nm in wavelength for gypsum under chemical additives. Other grey household dust and yellowish soil and pine tree pollen revealed a distinct chromaticity x, y coordinates shift in vector within the maximum range from (0.22, 0.19) to (0.55, 0.48). Applicable approaches to assist current particle matter sensors and improve the selective sensing were suggested.

Patterns of Prefrontal Activation and Performance During Walking Tasks Among Older Adults

Differences in prefrontal cortex (PFC) control of walking in older age likely arise from changes in neural capacity and compensation. PFC activation by changes in oxygenated hemoglobin from functional near infra-red spectroscopy was examined in 29 older adults (mean age=76). Tasks included standing with cognitive challenge and walking with and without cognitive challenge on even and uneven surfaces. Three PFC activation-performance patterns were identified using K-means clustering: 1) low activation during walking tasks and high activation during standing cognitive task, with the best performance in terms of walking speed and cognitive performance (n=10); 2) low activation on all tasks, with the lowest performance (n=15); 3) high activation during walking and low activation during cognitive, with intermediate performance (n=5). Associations of patterns with cognitive function and structural neuroimaging were explored, with results informing interpretation of functional changes of PFC during aging process, including compensatory mechanisms for primary network impairment.

Motor Adaptation to Cognitive Challenges and Destabilizing Treadmill Walking in Healthy Older Adults

To develop effective fall prevention intervention, it is necessary to understand how older adults respond to challenges that demand cognitive-motor dual-tasking capability, an important capability in the daily lives. The purpose of this study is to investigate how older adults adjust their motor responses when encountering cognitive and walking perturbations simultaneously. We recorded kinematic data as subjects walked on a treadmill with or without 1) continuous random-amplitude treadmill platform sways (Perturbed vs. No-perturbed walking); and 2) each of the four cognitive tasks: Paced Auditory Serial Addition test (PASAT), clock test, visual color-word incongruent test (V-stroop), and auditory pitch-word incongruent test (A-stroop). We computed dynamic margins of stability (MOS), gait variability, and short-term local divergence exponent (LDE) of the trunk motion (local stability). Data of ten older subjects (age: 72.2±4.9) show that cognitive performance did not differ between standing, Perturbed or No-perturbed walking. Subjects demonstrated significantly greater local instability and variability in step measures, joint angle and MOS during Perturbed than No-perturbed walking (p<0.001). During dual-task conditions, subjects walked with significantly larger medio-lateral MOS (MOSML) compared to walking only, especially during early phase of the trial. During Perturbed walking, subjects had significantly larger MOSML during PASAT and Vstroop than walking only. Our data showed that subjects tried to increase their dynamic MOS during Perturbed walking or a cognitive task more difficult or taxing visual attention. However, the adjustments do not sustain throughout the trial. These findings suggest older adults tend to prioritize cognitive over walking tasks even when encountering walking perturbations.

Prefrontal Cortex Control of Walking: Functional Near-Infrared Spectroscopy and Beyond

Cognitive control of walking may change with aging and is associated with poorer mobility and greater fall risk. The prefrontal cortex function is important for cognitive control of walking, and functional near-infrared spectroscopy (fNIRS) provides the primary means for assessing prefrontal activation during walking. Growing interest in fNIRS to assess cognitive control of walking has led to advancements in the methodologies for processing and analyzing the data, a greater sophistication of experimental protocols and participant samples, and implementation within intervention studies. These advancements will be highlighted in five presentations from an international group of researchers at the forefront of the field. First, Meltem Izzetoglu will provide direct comparisons of various data processing methodologies, demonstrating comparability across approaches. Three talks will demonstrate the range of applications of fNIRS to studying walking in older adults. Nemin Chen will present data on task-related patterns of prefrontal activation across walking tasks in relation to performance, cognitive function, and structural brain health. Sarah Fraser will present results from stair climbing, a critical task for daily function which also presents a fall risk. Inbal Maidan will examine how individual differences affect prefrontal activity during walking across older adults, younger adults, and patients with Parkinson’s disease or multiple sclerosis. Finally, David Clark will demonstrate the use of fNIRS in assessing outcomes from an intervention that combined walking with non-invasive frontal brain stimulation. Roee Holtzer will lead a discussion of the results and the future of fNIRS in assessing cognitive control of walking in older adults.

Obstacle negotiation in older adults: prefrontal activation interpreted through conceptual models of brain aging

Age-related decline in executive function is associated with walking deficits in older adults. The main objective of this study was to better understand the cognitive control of obstacle negotiation in older adults by identifying predictors of prefrontal recruitment during the task. The study also examined the association between prefrontal recruitment and walking performance as well as interpretation of prefrontal activity relative to cognitive models of brain aging. Prefrontal oxygenated hemoglobin concentration (O2Hb) was measured by functional near-infrared spectroscopy during typical walking (Typical) and obstacle negotiation (Obstacles) tasks in older adults. The primary outcome was change in prefrontal recruitment (∆PFR), measured as Obstacles ∆O2Hb minus Typical ∆O2Hb. Stepwise regression was used to identify potential predictors of ∆PFR. Additional analyses were conducted to further examine the relationship between ΔPFR and the identified predictors. Greater ∆PFR was predicted by lower age, worse executive function, and their interaction (R2=0.19 , p=0.02). Particularly, the effect of executive function on ∆PFR was more pronounced for “early aging” than for “late aging” older adults (p<0.001). Greater ∆PFR was significantly associated with a smaller reduction in walking speed during Obstacles compared to Typical. In conclusion, age, executive function, and their interaction predict prefrontal recruitment during obstacle negotiation in older adults. These findings are generally consistent with existing cognitive models of brain aging including neural inefficiency, compensatory overactivation, and capacity-limitation with a recruitment ceiling effect.

Combining frontal tDCS with walking rehabilitation to enhance mobility and cognition: a pilot clinical trial

Walking function is compromised with older age, particularly for cognitively demanding complex walking tasks. Frontal lobe brain networks are important to both complex walking and cognitive function. There is a need for interventions that target this brain region. This pilot study assessed a novel intervention to enhance both walking and executive function in older adults. The primary hypothesis was that eighteen sessions of frontal lobe tDCS combined with complex walking rehabilitation would be feasible, safe, and show preliminary efficacy for improvements in walking and cognition. Eighteen participants were randomized to one of three intervention groups: active tDCS and rehabilitation with complex walking tasks (Active/Complex); sham tDCS and rehabilitation with complex walking tasks (Sham/Complex); or sham tDCS and rehabilitation with typical walking (Sham/Typical). Outcome measures included multiple tests of walking function, executive function, and prefrontal activity during walking measured by functional near infrared spectroscopy. For the walking tests, effect sizes for Active/Complex were generally higher than for Sham/Complex. The Sham/Typical group exhibited walking test effect sizes that were often larger than either of the complex walking groups, possibly due to higher intervention step count. For the executive function tests, effect sizes were largest for the Active/Complex group. Improvements in prefrontal activity during walking were observed, as conceptualized by the Compensation Related Utilization of Neural Circuits Hypothesis. These preliminary findings support that tDCS combined with complex walking rehabilitation in older adults is feasible and may enhance both walking function and executive function.

FNIRS Outcomes for a Pilot Clinical Trial Combining Frontal tDCS With Walking Rehabilitation in Older Adults

This pilot study assessed a novel intervention to enhance both walking and executive function in older adults. The primary hypothesis was that eighteen sessions of frontal lobe tDCS combined with walking rehabilitation would be feasible, safe, and show preliminary efficacy. Eighteen participants were randomized to one of three intervention groups: active tDCS and rehabilitation with complex walking tasks (Active/Complex); sham tDCS and rehabilitation with complex walking tasks (Sham/Complex); or sham tDCS and rehabilitation with typical walking (Sham/Typical). Outcome measures included multiple tests of walking function, executive function, and prefrontal activity during walking as measured by functional near infrared spectroscopy (fNIRS). Of the three groups, the Active/Complex group demonstrated the broadest improvements across outcome measures including for prefrontal activity. The functional range of prefrontal activity in this group was increased considerably, as conceptualized by the Compensation Related Utilization of Neural Circuits Hypothesis. Frontal tDCS is a promising adjuvant to walking rehabilitation.

A methodology for the customization of hinged ankle-foot orthoses based on in vivo helical axis calculation with 3D printed rigid shells.

This study aims to develop techniques for ankle joint kinematics analysis using motion capture based on stereophotogrammetry. The scope is to design marker attachments on the skin for a most reliable identification of the instantaneous helical axis, to be targeted for the fabrication of customized hinged ankle-foot orthoses. These attachments should limit the effects of the experimental artifacts, in particular the soft-tissue motion artifact, which affect largely the accuracy of any in vivo ankle kinematics analysis. Motion analyses were carried out on two healthy subjects wearing customized rigid shells that were designed through 3D scans of the subjects' lower limbs and fabricated by additive manufacturing. Starting from stereophotogrammetry data collected during walking and dorsi-plantarflexion motor tasks, the instantaneous and mean helical axes of ankle joint were calculated. The customized shells matched accurately the anatomy of the subjects and allowed for the definition of rigid marker clusters that improved the accuracy of in vivo kinematic analyses. The proposed methodology was able to differentiate between subjects and between the motor tasks analyzed. The observed position and dispersion of the axes were consistent with those reported in the literature. This methodology represents an effective tool for supporting the customization of hinged ankle-foot orthoses or other devices interacting with human joints functionality.

Efficacy of transcranial direct current stimulation and over-ground walking task on functional mobility and quality of life of stroke survivors

Introduction: High proportion of stroke survivors have impaired functional mobility and decrease in overall quality of life (QoL). Transcranial direct current stimulation (tDCS) (non-invasive brain stimulation) and over-ground walking task (OGWT) (functional task-oriented training) have been suggested to improve functional mobility and QoL of stroke survivors. Hence, this study determined the efficacy of tDCS (anodal and cathodal) with OGWT on functional mobility and QoL of stroke survivors. Materials and methods: Seventy eight (78) stroke survivors were randomised into three groups: anodal group (anodal tDCS with OGWT); cathodal group (cathodal tDCS with OGWT) and control group (OGWT only). Participants had two sessions of intervention per week for six weeks. Functional mobility was assessed using 10 meter walk test (10MWT) measuring steps, time and velocity while QoL was measured using Stroke Specific QoL (SSQoL) scale. Significance level was set at p &lt; 0.05. Results: Participants (46 males) were aged 56.78 ± 10.24 years. The groups were matched for functional mobility and QoL at baseline and only work/productivity domain of SSQoL showed statistically significant difference (p = 0.028). Each group showed statistically significant improvement between baseline and post-intervention scores of items in functional mobility (p ≤ 0.001) and total SSQoL (p ≤ 0.001). Anodal group showed better statistically significant improvement in step (p = 0.008), time (p = 0.024), velocity (p = 0.001) and total SSQoL (p = 0.016) among the groups when the mean differences were compared. Conclusion: tDCS with OGWT is efficacious in improving functional mobility and QoL of stroke survivors. Specifically anodal tDCS with OGWT showed better clinical improvement in step, time, velocity and QoL in stroke survivors.

Gait disturbances are associated with increased CSF tau levels in a memory clinic cohort

AbstractBackgroundGait analysis with accelerometers is a relatively inexpensive and easy to use method to potentially support clinical diagnoses of Alzheimer’s Disease and other dementias. It is not clear however, which gait features are most informative and how these measures relate to Alzheimer pathology. In this study, we used in‐depth evaluation of gait in cognitively normal (CN) subjects, Mild Cognitive Impairment (MCI) patients, and dementia patients. We evaluated the associations between dynamics of gait, level of cognitive impairment and CSF biomarkers of Alzheimer’s pathology.MethodWe included CN participants (n=58), MCI patients (n=58) and participants with different types of dementia (n=26) of the multicenter PredictND cohort. Participants performed gait tests in two conditions: a normal walk task and a cognitively complex dual task. Gait was measured using tri‐axial accelerometers attached to the fifth lumbar vertebra (L5). Following principal component analysis, calculated gait features were clustered into four domains: pace, rhythm, time variability and length variability. Associations between gait domains, clinical diagnosis and CSF biomarkers (Aβ42, total tau, pTau) were examined using linear mixed models, included an interaction term with condition (normal and dual walk task) and were corrected for age, sex and center.ResultDementia patients showed gait disturbances in the pace domain ((p&lt;0.05), Figure 1, first row), meaning that dementia patients walk slower and with a smaller step length compared to CN and MCI participants. Rhythm disturbances were associated with increased levels of CSF (p)tau in the dual task (Figure 1, third and fourth row). No associations were found with CSF Aβ42 levels in any gait domain (Figure 1, second row).ConclusionThese findings suggest that gait disturbances increase with level of syndrome diagnosis. Moreover, rhythm disturbances increase with higher levels of CSF total tau and pTau, providing evidence for a direct link with neurodegeneration. These results demonstrate that in‐depth gait analysis with accelerometers might be a potential helpful tool to support clinical diagnosis or can be used as clinical outcome tool in clinical trials.