scholarly journals Split-Belt walking induces changes in active, but not passive, perception of step length

2019 ◽  
Author(s):  
Carly Sombric ◽  
Marcela Gonzalez-Rubio ◽  
Gelsy Torres-Oviedo
Keyword(s):  
Motor Control ◽  
Motor Adaptation ◽  
Arm Movements ◽  
Step Length ◽  
Active Perception ◽  
Limb Position ◽  
Post Stroke ◽  
Gait Asymmetry ◽  
Sensory Changes ◽  
Young Subjects

AbstractThe estimation of limbs’ position is critical for motor control. While motor adaptation changes the estimation of limb position in volitional arm movements, this has not been observed in locomotion. We hypothesized that split-belt walking with the legs moving at different speeds changes the estimation of the legs’ position when taking a step. Thus, we assessed young subjects’ perception of step length (i.e., inter-feet distance at foot landing) when they moved their legs (active perception) or these were moved by the experimenter (passive perception). Step length’s active, but not passive perception was altered by split-belt walking; indicating that adapted efferent inputs changed the perceived limbs’ position without changing information from sensory signals. These perceptual shifts were sensitive to how they were tested: they were observed in the trailing, but not the leading leg, and they were more salient when tested with short than long step lengths. Our results suggest that sensory changes following motor adaptation might arise from mismatched limb position estimates from different sensory sources (i.e., proprioception and vision), which is less prominent in walking. We also speculate that split-belt walking could improve the deficient perception of step length post-stroke, which contributes to their gait asymmetry impairing patients’ mobility.

scholarly journals Split-Belt walking induces changes in active, but not passive, perception of step length

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Carly Sombric ◽  
Marcela Gonzalez-Rubio ◽  
Gelsy Torres-Oviedo
Keyword(s):  
Motor Control ◽  
Motor Adaptation ◽  
Step Length ◽  
Accurate Estimation ◽  
Active Perception ◽  
Limb Position ◽  
Sensory Signals ◽  
Post Stroke ◽  
Young Subjects

Abstract Successful motor control requires accurate estimation of our body in space for planning, executing, and evaluating the outcome of our actions. It has been shown that the estimation of limb position is susceptible to motor adaptation. However, a similar effect has not been found in locomotion, possibly due to how it was tested. We hypothesized that split-belt walking with the legs moving at different speeds changes the estimation of the legs’ position when taking a step. Thus, we assessed young subjects’ perception of step length (i.e., inter-feet distance at foot landing) when they moved their legs (active perception) or when the legs were moved by the experimenter (passive perception). We found that the active perception of step length was substantially altered following split-belt walking, whereas passive perception exhibited minor changes. This suggests that split-belt walking induced the adaptation of efferent signals, without altering sensory signals. We also found that active perceptual shifts were sensitive to how they were tested: they were most salient in the trailing leg and at short step lengths. Our results suggest that split-belt walking could modulate the deficient perception of step length post-stroke, which may contribute to gait asymmetries impairing patients’ mobility.

scholarly journals Augmenting propulsion demands during split-belt walking increases locomotor adaptation in the asymmetric motor system

2019 ◽  
Author(s):  
Carly J. Sombric ◽  
Gelsy Torres-Oviedo
Keyword(s):  
Neurological Disorders ◽  
Motor System ◽  
Motor Behavior ◽  
Motor Adaptation ◽  
Chronic Phase ◽  
Step Length ◽  
After Effects ◽  
Post Stroke ◽  
Locomotor Adaptation ◽  
Rehabilitation Strategy

AbstractBackgroundPromising studies have shown that the mobility of individuals with hemiparesis due to brain lesions, such as stroke, can improve through motor adaptation protocols forcing patients to use their affected limb more. However, little is known about how to facilitate this process. Here we asked if increasing propulsion demands during split-belt walking (i.e., legs moving at different speeds) leads to more motor adaptation and more symmetric gait in survivors of a stroke, as we previously observed in subjects without neurological disorders.MethodsWe investigated the effect of propulsion forces on locomotor adaptation during and after split-belt walking in the asymmetric motor system post-stroke. To test this, 12 subjects in the chronic phase post-stroke experienced a split-belt protocol in a flat and incline session so as to contrast the effects of two different propulsion demands. Step length asymmetry and propulsion forces were used to compare the motor behavior between the two sessions because these are clinically relevant measures that are altered by split-belt walking.ResultsThe incline session resulted in more symmetric step lengths during late split-belt walking and larger after-effects following split-belt walking. In both testing sessions, subjects who have had a stroke adapted to regain speed and slope-specific leg orientations similarly to young, intact adults. Importantly, leg orientations during baseline walking were predictive of those achieved during split-belt walking, which in turn predicted each individual’s post-adaptation behavior.ConclusionThese results indicated that survivors of a stroke can adapt their movements to meet leg-specific kinetic demands. This promising finding suggests that augmenting propulsion demands during split-belt walking could favor symmetric walking in individuals who had a stroke, possibly making split-belt interventions a more effective gait rehabilitation strategy.

scholarly journals Effect of robotic-assisted gait training on objective biomechanical measures of gait in persons post-stroke: a systematic review and meta-analysis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Heidi Nedergård ◽  
Ashokan Arumugam ◽  
Marlene Sandlund ◽  
Anna Bråndal ◽  
Charlotte K. Häger
Keyword(s):  
Kinetic Parameters ◽  
Step Length ◽  
Gait Training ◽  
Risk Of Bias ◽  
Current Evidence ◽  
Temporal Asymmetry ◽  
Robotic Assisted ◽  
Post Stroke ◽  
Gait Biomechanics ◽  
Affected Side

Abstract Background Robotic-Assisted Gait Training (RAGT) may enable high-intensive and task-specific gait training post-stroke. The effect of RAGT on gait movement patterns has however not been comprehensively reviewed. The purpose of this review was to summarize the evidence for potentially superior effects of RAGT on biomechanical measures of gait post-stroke when compared with non-robotic gait training alone. Methods Nine databases were searched using database-specific search terms from their inception until January 2021. We included randomized controlled trials investigating the effects of RAGT (e.g., using exoskeletons or end-effectors) on spatiotemporal, kinematic and kinetic parameters among adults suffering from any stage of stroke. Screening, data extraction and judgement of risk of bias (using the Cochrane Risk of bias 2 tool) were performed by 2–3 independent reviewers. The Grading of Recommendations Assessment Development and Evaluation (GRADE) criteria were used to evaluate the certainty of evidence for the biomechanical gait measures of interest. Results Thirteen studies including a total of 412 individuals (mean age: 52–69 years; 264 males) met eligibility criteria and were included. RAGT was employed either as monotherapy or in combination with other therapies in a subacute or chronic phase post-stroke. The included studies showed a high risk of bias (n = 6), some concerns (n = 6) or a low risk of bias (n = 1). Meta-analyses using a random-effects model for gait speed, cadence, step length (non-affected side) and spatial asymmetry revealed no significant differences between the RAGT and comparator groups, while stride length (mean difference [MD] 2.86 cm), step length (affected side; MD 2.67 cm) and temporal asymmetry calculated in ratio-values (MD 0.09) improved slightly more in the RAGT groups. There were serious weaknesses with almost all GRADE domains (risk of bias, consistency, directness, or precision of the findings) for the included outcome measures (spatiotemporal and kinematic gait parameters). Kinetic parameters were not reported at all. Conclusion There were few relevant studies and the review synthesis revealed a very low certainty in current evidence for employing RAGT to improve gait biomechanics post-stroke. Further high-quality, robust clinical trials on RAGT that complement clinical data with biomechanical data are thus warranted to disentangle the potential effects of such interventions on gait biomechanics post-stroke.

The effect of frequency of feedback on overground temporal gait asymmetry post stroke

2021 ◽  
pp. 1-10
Author(s):  
Jessica Powers ◽  
Aaron Wallace ◽  
Avril Mansfield ◽  
George Mochizuki ◽  
Kara K Patterson
Keyword(s):  
Post Stroke ◽  
Gait Asymmetry

Quantitative Models of Motor Responses Subject to Longitudinal, Lateral, and Preview Constraints

1978 ◽  
Vol 20 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Tarald O. Kvålseth
Keyword(s):  
Experimental Data ◽  
Motor Control ◽  
Linear Models ◽  
Movement Time ◽  
Arm Movements ◽  
Second Order ◽  
Motor Responses ◽  
First Order ◽  
Different Types ◽  
Index Of Difficulty

First- and second-order linear models of mean movement time for serial arm movements aimed at a target and subject to preview constraints and lateral constraints were formulated as extensions of the so-called Fitts's law of motor control. These models were validated on the basis of experimental data from five subjects and found to explain from 80% to 85% of the variation in movement time in the case of the first-order models and from 93% to 95% of such variation for the second-order models. Fitts's index of difficulty (ID) was generally found to contribute more to the movement time than did either the preview ID or the lateral ID defined. Of the different types of errors, target overshoots occurred far more frequently than undershoots.

Abstract W P140: Post-stroke Oculomotor Abnormalities evident during Objective Eye Tracking but Not under Clinical Assessment

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
John-Ross Rizzo ◽  
Todd Hudson ◽  
Briana Kowal ◽  
Michal Wiseman ◽  
Preeti Raghavan
Keyword(s):  
Motor Control ◽  
Eye Movements ◽  
Eye Movement ◽  
Oculomotor Control ◽  
Healthy Controls ◽  
Visually Guided ◽  
Stroke Patients ◽  
Movement Execution ◽  
Post Stroke ◽  
Control Post

Introduction: Visual abnormalities and manual motor control have been studied extensively after stroke, but an understanding of oculomotor control post-stroke has not. Recent studies have revealed that in visually guided reaches arm movements are planned during eye movement execution, which may contribute to increased task complexity. In fact, in healthy controls during visually guided reaches, the onset of eye movement is delayed, its velocity reduced, and endpoint errors are larger relative to isolated eye movements. Our objective in this experiment was to examine the temporal properties of eye movement execution for stroke patients with no diagnosed visual impairment. The goal is to improve understanding of oculomotor control in stroke relative to normal function, and ultimately further understand its coordination with manual motor control during joint eye and hand movements. We hypothesized that stroke patients would show abnormal initiation or onset latency for saccades made in an eye movement task, as compared to healthy controls. Methods: We measured the kinematics of eye movements during point-to-point saccades; there was an initial static, fixation point and the stimulus was a flashed target on a computer monitor. We used a video-based eye tracker for objective recording of the eye at a sampling frequency of 2000 Hz (SR Research, Eyelink). 10 stroke subjects, over 4 months from injury and with no diagnosed visual impairment, and 10 healthy controls completed 432 saccades in a serial fashion. Results: Stroke patients had significantly faster onset latencies as compared to healthy controls during saccades (99.5ms vs. 245.2ms, p=0.00058). Conclusion: A better understanding of the variations in oculomotor control post-stroke, which may go unnoticed during clinical assessment, may improve understanding of how eye control synchronizes with arm or manual motor control. This knowledge could assist in tailoring rehabilitative strategies to amplify motor recovery. For next steps, we will perform objective eye and hand recordings during visually guided reaches post-stroke to better understand the harmonization or lack thereof after neurologic insult.

scholarly journals Disentangling the energetic costs of step time asymmetry and step length asymmetry in human walking

2021 ◽  
Author(s):  
Jan Stenum ◽  
Julia T. Choi
Keyword(s):  
Energy Cost ◽  
Metabolic Cost ◽  
Step Length ◽  
Human Walking ◽  
Metabolic Power ◽  
Healthy Human ◽  
Time Asymmetry ◽  
Double Support ◽  
Post Stroke ◽  
The Cost

The metabolic cost of walking in healthy individuals increases with spatiotemporal gait asymmetries. Pathological gait, such as post-stroke, often has asymmetry in step lengths and step times which may contribute to an increased energy cost. But paradoxically, enforcing step length symmetry does not reduce metabolic cost of post-stroke walking. The isolated and interacting costs of asymmetry in step times and step lengths remain unclear, because previous studies did not simultaneously enforce spatial and temporal gait asymmetries. Here, we delineate isolated costs of asymmetry in step times and step lengths in healthy human walking. We first show that the cost of step length asymmetry is predicted by the cost of taking two non-preferred step lengths (one short and one long), but that step time asymmetry adds an extra cost beyond the cost of non-preferred step times. The metabolic power of step time asymmetry is about 2.5 times greater than the cost of step length asymmetry. Furthermore, the costs are not additive when walking with asymmetric step times and step lengths: metabolic power of concurrent asymmetry in step lengths and step times is driven by the cost of step time asymmetry alone. The metabolic power of asymmetry is explained by positive mechanical power produced during single support phases to compensate for a net loss of center of mass power incurred during double support phases. These data may explain why metabolic cost remains invariant to step length asymmetry in post-stroke walking and suggests how effects of asymmetry on energy cost can be attenuated.

scholarly journals A Dual-Learning Paradigm Simultaneously Improves Multiple Features of Gait Post-Stroke

2018 ◽  
Vol 32 (9) ◽  
pp. 810-820 ◽  
Author(s):  
Kendra M. Cherry-Allen ◽  
Matthew A. Statton ◽  
Pablo A. Celnik ◽  
Amy J. Bastian
Keyword(s):  
Knee Flexion ◽  
Joint Angle ◽  
Step Length ◽  
Learning Task ◽  
Gait Pattern ◽  
Learning Paradigm ◽  
Post Stroke ◽  
Learning Conditions ◽  
Hip Flexion ◽  
Gait Impairments

Background. Gait impairments after stroke arise from dysfunction of one or several features of the walking pattern. Traditional rehabilitation practice focuses on improving one component at a time, which may leave certain features unaddressed or prolong rehabilitation time. Recent work shows that neurologically intact adults can learn multiple movement components simultaneously. Objective. To determine whether a dual-learning paradigm, incorporating 2 distinct motor tasks, can simultaneously improve 2 impaired components of the gait pattern in people posttroke. Methods. Twelve individuals with stroke participated. Participants completed 2 sessions during which they received visual feedback reflecting paretic knee flexion during walking. During the learning phase of the experiment, an unseen offset was applied to this feedback, promoting increased paretic knee flexion. During the first session, this task was performed while walking on a split-belt treadmill intended to improve step length asymmetry. During the second session, it was performed during tied-belt walking. Results. The dual-learning task simultaneously increased paretic knee flexion and decreased step length asymmetry in the majority of people post-stroke. Split-belt treadmill walking did not significantly interfere with joint-angle learning: participants had similar rates and magnitudes of joint-angle learning during both single and dual-learning conditions. Participants also had significant changes in the amount of paretic hip flexion in both single and dual-learning conditions. Conclusions. People with stroke can perform a dual-learning paradigm and change 2 clinically relevant gait impairments in a single session. Long-term studies are needed to determine if this strategy can be used to efficiently and permanently alter multiple gait impairments.

Muscle torques and joint accelerations provide more sensitive measures of post-stroke movement deficits than joint angles.

2021 ◽  
Author(s):  
Ariel B Thomas ◽  
Erienne V Olesh ◽  
Amelia Adcock ◽  
Valeriya Gritsenko
Keyword(s):  
Motor Control ◽  
Motion Capture ◽  
Reaching Movements ◽  
Motor Deficits ◽  
Joint Angles ◽  
Active Joint ◽  
Joint Torques ◽  
Post Stroke ◽  
Muscle Moments ◽  
Muscle Torques

The whole repertoire of complex human motion is enabled by forces applied by our muscles and controlled by the nervous system. The impact of stroke on the complex multi-joint motor control is difficult to quantify in a meaningful way that informs about the underlying deficit in the active motor control and intersegmental coordination. We tested whether post-stroke deficit can be quantified with high sensitivity using motion capture and inverse modeling of a broad range of reaching movements. Our hypothesis is that muscle moments estimated based on active joint torques provide a more sensitive measure of post-stroke motor deficits than joint angles. The motion of twenty-two participants was captured while performing reaching movements in a center-out task, presented in virtual reality. We used inverse dynamics analysis to derive active joint torques that were the result of muscle contractions, termed muscle torques, that caused the recorded multi-joint motion. We then applied a novel analysis to separate the component of muscle torque related to gravity compensation from that related to intersegmental dynamics. Our results show that muscle torques characterize individual reaching movements with higher information content than joint angles do. Moreover, muscle torques enable distinguishing the individual motor deficits caused by aging or stroke from the typical differences in reaching between healthy individuals. Similar results were obtained using metrics derived from joint accelerations. This novel quantitative assessment method may be used in conjunction with home-based gaming motion-capture technology for remote monitoring of motor deficits and inform the development of evidence-based robotic therapy interventions.

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