scholarly journals Blocking trial-by-trial error correction does not interfere with motor learning in human walking

2016 ◽  
Vol 115 (5) ◽  
pp. 2341-2348 ◽  
Author(s):  
Andrew W. Long ◽  
Ryan T. Roemmich ◽  
Amy J. Bastian
Keyword(s):  
Error Correction ◽  
Motor Pattern ◽  
Step Length ◽  
The Other ◽  
Human Walking ◽  
Not Given ◽  
Foot Placement ◽  
Locomotor Adaptation ◽  
Walking Pattern ◽  
Environmental Demands

Movements can be learned implicitly in response to new environmental demands or explicitly through instruction and strategy. The former is often studied in an environment that perturbs movement so that people learn to correct the errors and store a new motor pattern. Here, we demonstrate in human walking that implicit learning of foot placement occurs even when an explicit strategy is used to block changes in foot placement during the learning process. We studied people learning a new walking pattern on a split-belt treadmill with and without an explicit strategy through instruction on where to step. When there is no instruction, subjects implicitly learn to place one foot in front of the other to minimize step-length asymmetry during split-belt walking, and the learned pattern is maintained when the belts are returned to the same speed, i.e., postlearning. When instruction is provided, we block expression of the new foot-placement pattern that would otherwise naturally develop from adaptation. Despite this appearance of no learning in foot placement, subjects show similar postlearning effects as those who were not given any instruction. Thus locomotor adaptation is not dependent on a change in action during learning but instead can be driven entirely by an unexpressed internal recalibration of the desired movement.

scholarly journals Contributions of spatial and temporal control of step length symmetry in the transfer of locomotor adaptation from a motorized to a non-motorized split-belt treadmill

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
Daniel L. Gregory ◽  
Frank C. Sup ◽  
Julia T. Choi
Keyword(s):  
Step Length ◽  
Treadmill Walking ◽  
Speed Ratio ◽  
Foot Placement ◽  
After Effects ◽  
Locomotor Adaptation ◽  
Locomotor Control ◽  
Length Difference ◽  
Limb Coordination ◽  
Healthy Participants

Walking requires control of where and when to step for stable interlimb coordination. Motorized split-belt treadmills which constrain each leg to move at different speeds lead to adaptive changes to limb coordination that result in after-effects (e.g. gait asymmetry) on return to normal treadmill walking. These after-effects indicate an underlying neural adaptation. Here, we assessed the transfer of motorized split-belt treadmill adaptations with a custom non-motorized split-belt treadmill where each belt can be self-propelled at different speeds. Transfer was indicated by the presence of after-effects in step length, foot placement and step timing differences. Ten healthy participants adapted on a motorized split-belt treadmill (2 : 1 speed ratio) and were then assessed for after-effects during subsequent non-motorized treadmill and motorized tied-belt treadmill walking. We found that after-effects in step length difference during transfer to non-motorized split-belt walking were primarily associated with step time differences. Conversely, residual after-effects during motorized tied-belt walking following transfer were associated with foot placement differences. Our data demonstrate decoupling of adapted spatial and temporal locomotor control during transfer to a novel context, suggesting that foot placement and step timing control can be independently modulated during walking.

scholarly journals A marching-walking hybrid induces step length adaptation and transfers to natural walking

2015 ◽  
Vol 113 (10) ◽  
pp. 3905-3914 ◽  
Author(s):  
Andrew W. Long ◽  
James M. Finley ◽  
Amy J. Bastian
Keyword(s):  
Time Course ◽  
Stance Phase ◽  
Step Length ◽  
Foot Placement ◽  
Spatial Strategy ◽  
Walking Pattern ◽  
Significant Difference ◽  
Locomotor Patterns ◽  
Hybrid Group ◽  
Over Ground Walking

Walking is highly adaptable to new demands and environments. We have previously studied adaptation of locomotor patterns via a split-belt treadmill, where subjects learn to walk with one foot moving faster than the other. Subjects learn to adapt their walking pattern by changing the location (spatial) and time (temporal) of foot placement. Here we asked whether we can induce adaptation of a specific walking pattern when one limb does not “walk” but instead marches in place (i.e., marching-walking hybrid). The marching leg's movement is limited during the stance phase, and thus certain sensory signals important for walking may be reduced. We hypothesized that this would produce a spatial-temporal strategy different from that of normal split-belt adaptation. Healthy subjects performed two experiments to determine whether they could adapt their spatial-temporal pattern of step lengths during the marching-walking hybrid and whether the learning transfers to over ground walking. Results showed that the hybrid group did adapt their step lengths, but the time course of adaptation and deadaption was slower than that for the split-belt group. We also observed that the hybrid group utilized a mostly spatial strategy whereas the split-belt group utilized both spatial and temporal strategies. Surprisingly, we found no significant difference between the hybrid and split-belt groups in over ground transfer. Moreover, the hybrid group retained more of the learned pattern when they returned to the treadmill. These findings suggest that physical rehabilitation with this marching-walking paradigm on conventional treadmills may produce changes in symmetry comparable to what is observed during split-belt training.

scholarly journals Different Error Size During Locomotor Adaptation Affects Transfer to Overground Walking Poststroke

2018 ◽  
Vol 32 (12) ◽  
pp. 1020-1030 ◽  
Author(s):  
Carolina C. Alcântara ◽  
Charalambos C. Charalambous ◽  
Susanne M. Morton ◽  
Thiago L. Russo ◽  
Darcy S. Reisman
Keyword(s):  
Catch Trial ◽  
Step Length ◽  
Similar Amount ◽  
Adaptation Period ◽  
Overground Walking ◽  
Locomotor Adaptation ◽  
Walking Pattern ◽  
Gradual Group ◽  
Adaptation Response ◽  
Group A

Background. Studies in neurologically intact subjects suggest that the gradual presentation of small perturbations (errors) during learning results in better transfer of a newly learned walking pattern to overground walking. Whether the same result would be true after stroke is not known. Objective. To determine whether introducing gradual perturbations, during locomotor learning using a split-belt treadmill influences learning the novel walking pattern or transfer to overground walking poststroke. Methods. Twenty-six chronic stroke survivors participated and completed the following walking testing paradigm: baseline overground walking; baseline treadmill walking; split-belt treadmill/adaptation period (belts moving at different speeds); catch trial (belts at same speed); post overground walking. Subjects were randomly assigned to the Gradual group (gradual changes in treadmill belts speed during adaptation) or the Abrupt group (a single, large, abrupt change during adaptation). Step length asymmetry adaptation response on the treadmill and transfer of learning to overground walking was assessed. Results. Step length asymmetry during the catch trial was the same between groups ( P = .195) confirming that both groups learned a similar amount. The magnitude of transfer to overground walking was greater in the Gradual than in the Abrupt group ( P = .041). Conclusions. The introduction of gradual perturbations (small errors), compared with abrupt (larger errors), during a locomotor adaptation task seems to improve transfer of the newly learned walking pattern to overground walking poststroke. However, given the limited magnitude of transfer, future studies should examine other factors that could impact locomotor learning and transfer poststroke.

Circulating Anticoagulant (Antifactor VIII) Treated with Immunosuppressive Drugs

1969 ◽  
Vol 21 (02) ◽  
pp. 249-258 ◽  
Author(s):  
L. A Sherman ◽  
M. A Goldstein ◽  
H. S Sise
Keyword(s):  
Factor Viii ◽  
Conventional Therapy ◽  
Immunosuppressive Drugs ◽  
The Other ◽  
Not Given ◽  
Factor Viii Concentrates ◽  
Short Courses

SummaryThree cases have been presented who had a circulating antifactor VIII anticoagulant developing spontaneously in non-hemophilic subjects. Following two short courses of azathioprine in one case there were transient incomplete remissions of a degree not seen in the previous 4 months of observation. In the other two cases complete remissions were observed within three weeks of beginning administration of 6-mercaptopurine. In one of these, a brief relapse was retreated successfully. In 4 other cases not given these drugs and in cases reported in the literature, such a rapid remission was not seen to occur spontaneously and happened only infrequently in cases given corticosteroids. On the basis of this experience, we suggest that in the treatment of antifactor VIII, if the disorder shows no improvement with conventional therapy (blood, factor VIII concentrates, and corticosteroids), a trial with immunosuppressive drugs is warranted.

scholarly journals Fluid Cognitive Abilities Are Important for Learning and Retention of a New, Explicitly Learned Walking Pattern in Individuals After Stroke

2021 ◽  
pp. 154596832110010
Author(s):  
Margaret A. French ◽  
Matthew L. Cohen ◽  
Ryan T. Pohlig ◽  
Darcy S. Reisman
Keyword(s):  
Cognitive Abilities ◽  
Step Length ◽  
Cognitive Measures ◽  
Retention Models ◽  
Wechsler Memory Scale ◽  
Walking Pattern ◽  
Learning Principles ◽  
The Relationship ◽  
Sequential Regression ◽  
Neurologically Intact

Background There is significant variability in poststroke locomotor learning that is poorly understood and affects individual responses to rehabilitation interventions. Cognitive abilities relate to upper extremity motor learning in neurologically intact adults, but have not been studied in poststroke locomotor learning. Objective To understand the relationship between locomotor learning and retention and cognition after stroke. Methods Participants with chronic (>6 months) stroke participated in 3 testing sessions. During the first session, participants walked on a treadmill and learned a new walking pattern through visual feedback about their step length. During the second session, participants walked on a treadmill and 24-hour retention was assessed. Physical and cognitive tests, including the Fugl-Meyer-Lower Extremity (FM-LE), Fluid Cognition Composite Score (FCCS) from the NIH Toolbox -Cognition Battery, and Spatial Addition from the Wechsler Memory Scale-IV, were completed in the third session. Two sequential regression models were completed: one with learning and one with retention as the dependent variables. Age, physical impairment (ie, FM-LE), and cognitive measures (ie, FCCS and Spatial Addition) were the independent variables. Results Forty-nine and 34 participants were included in the learning and retention models, respectively. After accounting for age and FM-LE, cognitive measures explained a significant portion of variability in learning ( R2 = 0.17, P = .008; overall model R2 = 0.31, P = .002) and retention (Δ R2 = 0.17, P = .023; overall model R2 = 0.44, P = .002). Conclusions Cognitive abilities appear to be an important factor for understanding locomotor learning and retention after stroke. This has significant implications for incorporating locomotor learning principles into the development of personalized rehabilitation interventions after stroke.

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 Online Biped Walking Pattern Generation with Contact Consistency

2015 ◽  
Vol 4 (1) ◽  
pp. 19
Author(s):  
Wenqi Hou ◽  
Jian Wang ◽  
Jianwen Wang ◽  
Hongxu Ma
Keyword(s):  
Biped Robot ◽  
Gait Pattern ◽  
Pattern Generation ◽  
Task Space ◽  
Biped Walking ◽  
Foot Placement ◽  
Walking Gait ◽  
Walking Pattern ◽  
Generating Method ◽  
Stable Periodic

In this paper, a novel online biped walking gait pattern generating method with contact consistency is proposed. Generally, it’s desirable that there is no foot-ground slipping during biped walking. By treating the hip of the biped robot as a linear inverted pendulum (LIP), a foot placement controller that takes the contact consistency into account is proposed to tracking the desired orbit energy. By selecting the hip’s horizontal locomotion as the parameter, the trajectories in task space for walking are planned. A task space controller without calculating the inversion of inertial matrix is presented. Simulation experiments are implemented on a virtual 5-link point foot biped robot. The results show the effectiveness of the walking pattern generating method which can realize a stable periodic gait cycle without slipping and falling even suffering a sudden disturbance.

scholarly journals The etho-poietic of the parable of the good Samaritan (Lk 10:25-37). The ethics of seeing in a culture of looking the other way

2008 ◽  
Vol 29 (1) ◽  
pp. 269-292 ◽  
Author(s):  
R Zimmermann
Keyword(s):  
Social Ethics ◽  
The Other ◽  
Not Given ◽  
Emergency Situations ◽  
Good Samaritan

Within a culture of “Looking the Other way” there are not only empirically ascertainable reasons why help is not given in acute emergency situations, there is also a “Theory of Not-Helping” that attempts to demonstrate argumentatively why it may even be better not to help. According to the article, the parable of the “good Samaritan” invites us, however, to “look closely”. Four invitations of the text are developed, each with an emphasis on ethics: 1) The narrated Samaritan (The appeal structure of ethics); 2) The touched Samaritan (Ethics in the Context of Love); 3) The partisan Samaritan (Universal ethos of helping – or: Ethics of open partisanship); 4) The charitable Samaritan (Social ethics instead of ethics of conscience).

How to Engage Learners in Authentic Target Language Use - Examples from an Autonomy Classroom

10.47908/9/5 ◽  
2013 ◽  
pp. 96-117
Keyword(s):  
Language Use ◽  
Language Teachers ◽  
Intermediate Level ◽  
The Other ◽  
Autonomous Learning ◽  
Target Language ◽  
Not Given ◽  
German School ◽  
Authentic Language ◽  
Positive Results

‘But how can they say anything in the foreign language if they are not given the words beforehand?’ Language teachers often ask this question when I present examples of target language use in an autonomy classroom. This article explains how from the very beginning it is possible to engage pupils in authentic target language use, including communication that does not involve the teacher. The oral and written examples that I use to support my argument were produced by learners aged between 10 and 16 and ranging in proficiency from beginners to intermediate level. When I introduce each activity I also describe the pre-requisites for its success. In the last section of the article I summarise the positive results achieved in the autonomy classroom, which I illustrate using two sets of peer-to-peer talks collected by the LAALE project (Language Acquisition in an Autonomous Learning Environment), one from a ‘traditional’, communicative classroom in a German school, the other from a Danish autonomy classroom. I conclude by listing the essential features of an autonomous classroom supporting authentic language use.

scholarly journals Large Propulsion Demands Increase Locomotor Adaptation at the Expense of Step Length Symmetry

2019 ◽  
Vol 10 ◽  
Author(s):  
Carly J. Sombric ◽  
Jonathan S. Calvert ◽  
Gelsy Torres-Oviedo
Keyword(s):  
Step Length ◽  
Locomotor Adaptation
Sign in / Sign up

Export Citation Format

Share Document