Robot-aided sensorimotor arm training improves outcome in patients with chronic stroke

A Sensor-Based Upper Limb Treatment in Hemiplegic Patients: Results from a Randomized Pilot Study

In post-stroke patients, the disabling motor deficit mainly affects the upper limb. The focus of rehabilitation is improving upper limb function and reducing long-term disability. This study aims to evaluate the feasibility of using the Gloreha Aria (R-Lead), a sensor-based upper limb in-hospital rehabilitation, compared with conventional physiotherapist-led training in subacute hemiplegic patients. Twenty-one patients were recruited and randomised 1:1 to a sensor-based group (treatment group TG) or a conventional group (control group, CG). All patients performed 30 sessions of 30 min each of dedicated upper limb rehabilitation. The Fugl-Meyer Assessment for Upper Extremity (FMA-UE) was the primary evaluation., both as a motor score and as individual items. Secondary evaluations were Functional Independence Measure; global disability assessed with the Modified Barthel Index; Motor Evaluation Scale for UE in stroke; power grip; and arm, shoulder, and hand disability. All the enrolled patients, 10 in the TG and 11 in the CG, completed all hand rehabilitation sessions during their hospital stay without experiencing any adverse events. FMA-UE scores in upper limb motor function improved in both groups [delta change CG (11.8 ± 9.2) vs. TG (12.7 ± 8.6)]. The score at T1 for FMA joint pain (21.8 vs. 24 best score) suggests the use of the Gloreha Aria (R-Lead) as feasible in improving arm function abilities in post-stroke patients.

Relation Between Sensorimotor Rhythm During Motor Attempt/Imagery and Upper-Limb Motor Impairment in Stroke

Motor attempt (MA)/motor imagery (MI)-based brain-computer interface (BCI) is a newly developing rehabilitation technology for motor impairment. This study aims to explore the relationship between electroencephalography sensorimotor rhythm and motor impairment to provide reference for a BCI design. Twenty-eight stroke survivors with varying levels of motor dysfunction and spasticity status in the subacute or chronic stage were enrolled in the study to perform MA and MI tasks. Event-related desynchronization (ERD)/event-related synchronization (ERS) during and immediately after motor tasks were calculated. The Fugl-Meyer assessment scale (FMA) and the modified Ashworth scale (MAS) were applied to characterize upper-limb motor dysfunction and spasticity. There was a positive correlation between FMA total scores and ERS in the contralesional hemisphere in the MI task (P < .05) and negative correlations between FMA total scores and ERD in both hemispheres in the MA task (P < .05). Negative correlations were found between MAS scores of wrist flexors and ERD in the ipsilesional hemisphere (P < .05) in the MA task. It suggests that motor dysfunction may be more correlated to ERS in the MI task and to ERD in the MA task while spasticity may be more correlated to ERD in the MA task.

Efficacy of wrist robot-aided orthopedic rehabilitation: a randomized controlled trial

Background

In recent years, many studies focused on the use of robotic devices for both the assessment and the neuro-motor reeducation of upper limb in subjects after stroke, spinal cord injuries or affected by neurological disorders. Contrarily, it is still hard to find examples of robot-aided assessment and rehabilitation after traumatic injuries in the orthopedic field. However, those benefits related to the use of robotic devices are expected also in orthopedic functional reeducation.

Methods

After a wrist injury occurred at their workplace, wrist functionality of twenty-three subjects was evaluated through a robot-based assessment and clinical measures (Patient Rated Wrist Evaluation, Jebsen-Taylor and Jamar Test), before and after a 3-week long rehabilitative treatment. Subjects were randomized in two groups: while the control group (n = 13) underwent a traditional rehabilitative protocol, the experimental group (n = 10) was treated replacing traditional exercises with robot-aided ones.

Results

Functionality, assessed through the function subscale of PRWE scale, improved in both groups (experimental p = 0.016; control p < 0.001) and was comparable between groups, both pre (U = 45.5, p = 0.355) and post (U = 47, p = 0.597) treatment. Additionally, even though groups’ performance during the robotic assessment was comparable before the treatment (U = 36, p = 0.077), after rehabilitation the experimental group presented better results than the control one (U = 26, p = 0.015).

Conclusions

This work can be considered a starting point for introducing the use of robotic devices in the orthopedic field. The robot-aided rehabilitative treatment was effective and comparable to the traditional one. Preserving efficacy and safety conditions, a systematic use of these devices could lead to decrease human therapists’ effort, increase repeatability and accuracy of assessments, and promote subject’s engagement and voluntary participation. Trial Registration ClinicalTrial.gov ID: NCT04739644. Registered on February 4, 2021—Retrospectively registered, https://www.clinicaltrials.gov/ct2/show/study/NCT04739644.

Design and Preliminary Evaluation of a Tongue-Operated Exoskeleton System for Upper Limb Rehabilitation

Stroke is a devastating condition that may cause upper limb paralysis. Robotic rehabilitation with self-initiated and assisted movements is a promising technology that could help restore upper limb function. Previous studies have established that the tongue motion can be used to communicate human intent and control a rehabilitation robot/assistive device. The goal of this study was to evaluate a tongue-operated exoskeleton system (TDS-KA), which we have developed for upper limb rehabilitation. We adopted a tongue-operated assistive technology, called the tongue drive system (TDS), and interfaced it with the exoskeleton KINARM. We also developed arm reaching and tracking tasks, controlled by different tongue operation modes, for training and evaluation of arm motor function. Arm reaching and tracking tasks were tested in 10 healthy participants (seven males and three females, 23-60 years) and two female stroke survivors with upper extremity impairment (32 and 58 years). All healthy and two stroke participants successfully performed the tasks. One stroke subject demonstrated a clinically significant improvement in Fugl-Meyer upper extremity score after practicing the tasks in six 3-h sessions. We conclude that the TDS-KA system can accurately translate tongue commands to exoskeleton arm movements, quantify the function of the arm, and perform rehabilitation training.

Robot-Assisted Therapy and Constraint-Induced Movement Therapy for Motor Recovery in Stroke: Results From a Randomized Clinical Trial

Background: Stroke is one of the leading causes of adult disability, and up to 80% of stroke survivors undergo upper extremity motor dysfunction. Constraint-Induced Movement Therapy (CIMT) and Robot-Assisted Therapy (RT) are used for upper limb stroke rehabilitation. Although CIMT and RT are different techniques, both are beneficial; however, their results must be compared. The objective is to establish the difference between RT and CIMT after a rehabilitation program for chronic stroke patients.

Method: This is a randomized clinical trial, registered at ClinicalTrials.gov (ID number NCT02700061), in which patients with stroke received sessions of RT or CIMT protocol, combined with a conventional rehabilitation program for 12 weeks. The primary outcome was measured by Wolf Motor Function Test (WMFT) and Fugl-Meyer Assessment—Upper Limb (FMA-UL). Activities of daily living were also assessed.

Results: Fifty one patients with mild to moderate upper limb impairment were enrolled in this trial, 25 women and 26 men, mean age of 60,02 years old (SD 14,48), with 6 to 36 months after stroke onset. Function significantly improved regardless of the treatment group. However, no statistical difference was found between both groups as p-values of the median change of function measured by WMFT and FMA were 0.293 and 0.187, respectively.

Conclusion: This study showed that Robotic Therapy (RT) was not different from Constraint-Induced Movement Therapy (CIMT) regardless of the analyzed variables. There was an overall upper limb function, motor recovery, functionality, and activities of daily living improvement regardless of the interventions. At last, the combination of both techniques should be considered in future studies.

Arm Motor Recovery After Ischemic Stroke: A Focus on Clinically Distinct Trajectory Groups

BACKGROUND AND PURPOSE

Recovery of arm function poststroke is highly variable with some people experiencing rapid recovery but many experiencing slower or limited functional improvement. Current stroke prediction models provide some guidance for clinicians regarding expected motor outcomes poststroke but do not address recovery rates, complicating discharge planning. This study developed a novel approach to defining recovery groups based on arm motor recovery trajectories poststroke. In addition, between-group differences in baseline characteristics and therapy hours were explored.

METHODS

A retrospective cohort analysis was conducted where 40 participants with arm weakness were assessed 1 week, 6 weeks, 3 months, and 6 months after an ischemic stroke. Arm recovery trajectory groups were defined on the basis of timing of changes in the Fugl-Meyer Assessment Upper Extremity (FMA-UE), at least the minimal clinically important difference (MCID), 1 week to 6 weeks or 6 weeks to 6 months. Three recovery trajectory groups were defined: Fast (n = 19), Extended (n = 12), and Limited (n = 9). Between-group differences in baseline characteristics and therapy hours were assessed. Associations between baseline characteristics and group membership were also determined.

RESULTS

Three baseline characteristics were associated with trajectory group membership: FMA-UE, NIH Stroke Scale, and Barthel Index. The Fast Recovery group received the least therapy hours 6 weeks to 6 months. No differences in therapy hours were observed between Extended and Limited Recovery groups at any time points.

DISCUSSION AND CONCLUSIONS

Three clinically relevant recovery trajectory groups were defined using the FMA-UE MCID. Baseline impairment, overall stroke severity, and dependence in activities of daily living were associated with group membership and therapy hours differed between groups. Stratifying individuals by recovery trajectory early poststroke could offer additional guidance to clinicians in discharge planning.

(See Supplemental Digital Content 1 for Video Abstract, available at: http://links.lww.com/JNPT/A337.).

Accurate prediction of clinical stroke scales and improved biomarkers of motor impairment from robotic measurements

Objective

One of the greatest challenges in clinical trial design is dealing with the subjectivity and variability introduced by human raters when measuring clinical end-points. We hypothesized that robotic measures that capture the kinematics of human movements collected longitudinally in patients after stroke would bear a significant relationship to the ordinal clinical scales and potentially lead to the development of more sensitive motor biomarkers that could improve the efficiency and cost of clinical trials.

Materials and methods

We used clinical scales and a robotic assay to measure arm movement in 208 patients 7, 14, 21, 30 and 90 days after acute ischemic stroke at two separate clinical sites. The robots are low impedance and low friction interactive devices that precisely measure speed, position and force, so that even a hemiparetic patient can generate a complete measurement profile. These profiles were used to develop predictive models of the clinical assessments employing a combination of artificial ant colonies and neural network ensembles.

Results

The resulting models replicated commonly used clinical scales to a cross-validated R² of 0.73, 0.75, 0.63 and 0.60 for the Fugl-Meyer, Motor Power, NIH stroke and modified Rankin scales, respectively. Moreover, when suitably scaled and combined, the robotic measures demonstrated a significant increase in effect size from day 7 to 90 over historical data (1.47 versus 0.67).

Discussion and conclusion

These results suggest that it is possible to derive surrogate biomarkers that can significantly reduce the sample size required to power future stroke clinical trials.

Robotic Rehabilitation and Multimodal Instrumented Assessment of Post-stroke Elbow Motor Functions-A Randomized Controlled Trial Protocol

Background: The reliable assessment, attribution, and alleviation of upper-limb joint stiffness are essential clinical objectives in the early rehabilitation from stroke and other neurological disorders, to prevent the progression of neuromuscular pathology and enable proactive physiotherapy toward functional recovery. However, the current clinical evaluation and treatment of this stiffness (and underlying muscle spasticity) are severely limited by their dependence on subjective evaluation and manual limb mobilization, thus rendering the evaluation imprecise and the treatment insufficiently tailored to the specific pathologies and residual capabilities of individual patients.

Methods: To address these needs, the proposed clinical trial will employ the NEUROExos Elbow Module (NEEM), an active robotic exoskeleton, for the passive mobilization and active training of elbow flexion and extension in 60 sub-acute and chronic stroke patients with motor impairments (hemiparesis and/or spasticity) of the right arm. The study protocol is a randomized controlled trial consisting of a 4-week functional rehabilitation program, with both clinical and robotically instrumented assessments to be conducted at baseline and post-treatment. The primary outcome measures will be a set of standard clinical scales for upper limb spasticity and motor function assessment, including the Modified Ashworth Scale and Fugl-Meyer Index, to confirm the safety and evaluate the efficacy of robotic rehabilitation in reducing elbow stiffness and improving function. Secondary outcomes will include biomechanical, muscular activity, and motor performance parameters extracted from instrumented assessments using the NEEM along with synchronous EMG recordings.

Conclusions: This randomized controlled trial aims to validate an innovative instrumented methodology for clinical spasticity assessment and functional rehabilitation, relying on the precision and accuracy of an elbow exoskeleton combined with EMG recordings and the expertise of a physiotherapist, thus complementing and maximizing the benefits of both practices.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT04484571.

There is No test-retest reliability of brain activation induced by robotic passive hand movement: A functional NIRS study

INTRODUCTION

The basic paradigm of rehabilitation is based on the brain plasticity, and for promoting it, test-retest reliability (TRR) of brain activation in which certain area of the brain is repeatedly activated is required. In this study, we investigated whether the robotic passive movement has the TRR of brain activation. While active training has been shown to have TRR, but there still have been arguments over the TRR by passive movement.

METHODS

In order to test TRR, 10 repetitive sessions and various intervals (1 day, 3 days, 7 days, 23 days, 15 min, and 6 hr) were applied to five subjects, which had the same statistical power as applying two sessions to 50 subjects. In each session, three robot speeds (0.25, 0.5, and 0.75 Hz) were applied to provide passive movement using the robot. The fNIRS signal (oxy-Hb) generated in the primary sensorimotor area (SM1) was measured on a total of 29 channels. At this time, we used activation maps and intraclass correlation coefficient (ICC) values to examine the TRR and the effect of robot speeds and intervals on TRR.

RESULTS

As a result, activation maps showed prominent variation regardless of robot speeds and interval, and the ICC value (=0.002) showed no TRR of brain activation for robotic passive movement.

CONCLUSION

The brain activation induced by the robotic passive movement alone has very poor TRR, suggesting that further enhancement is required to strengthen the TRR by complementing active user engagements.

Task-based hybrid shared control for training through forceful interaction

Despite the fact that robotic platforms can provide both consistent practice and objective assessments of users over the course of their training, there are relatively few instances where physical human–robot interaction has been significantly more effective than unassisted practice or human-mediated training. This article describes a hybrid shared control robot, which enhances task learning through kinesthetic feedback. The assistance assesses user actions using a task-specific evaluation criterion and selectively accepts or rejects them at each time instant. Through two human subject studies (total [Formula: see text]), we show that this hybrid approach of switching between full transparency and full rejection of user inputs leads to increased skill acquisition and short-term retention compared with unassisted practice. Moreover, we show that the shared control paradigm exhibits features previously shown to promote successful training. It avoids user passivity by only rejecting user actions and allowing failure at the task. It improves performance during assistance, providing meaningful task-specific feedback. It is sensitive to initial skill of the user and behaves as an “assist-as-needed” control scheme, adapting its engagement in real time based on the performance and needs of the user. Unlike other successful algorithms, it does not require explicit modulation of the level of impedance or error amplification during training and it is permissive to a range of strategies because of its evaluation criterion. We demonstrate that the proposed hybrid shared control paradigm with a task-based minimal intervention criterion significantly enhances task-specific training.

Robot-Assisted Arm Training in Chronic Stroke: Addition of Transition-to-Task Practice

Background. Robot-assisted therapy provides high-intensity arm rehabilitation that can significantly reduce stroke-related upper extremity (UE) deficits. Motor improvement has been shown at the joints trained, but generalization to real-world function has not been profound. Objective. To investigate the efficacy of robot-assisted therapy combined with therapist-assisted task training versus robot-assisted therapy alone on motor outcomes and use in participants with moderate to severe chronic stroke-related arm disability. Methods. This was a single-blind randomized controlled trial of two 12-week robot-assisted interventions; 45 participants were stratified by Fugl-Meyer (FMA) impairment (mean 21 ± 1.36) to 60 minutes of robot therapy (RT; n = 22) or 45 minutes of RT combined with 15 minutes therapist-assisted transition-to-task training (TTT; n = 23). The primary outcome was the mean FMA change at week 12 using a linear mixed-model analysis. A subanalysis included the Wolf Motor Function Test (WMFT) and Stroke Impact Scale (SIS), with significance P <.05. Results. There was no significant 12-week difference in FMA change between groups, and mean FMA gains were 2.87 ± 0.70 and 4.81 ± 0.68 for RT and TTT, respectively. TTT had greater 12-week secondary outcome improvements in the log WMFT (-0.52 ± 0.06 vs -0.18 ± 0.06; P = .01) and SIS hand (20.52 ± 2.94 vs 8.27 ± 3.03; P = .03). Conclusion. Chronic UE motor deficits are responsive to intensive robot-assisted therapy of 45 or 60 minutes per session duration. The replacement of part of the robotic training with nonrobotic tasks did not reduce treatment effect and may benefit stroke-affected hand use and motor task performance.

Early Findings on Functional Connectivity Correlates of Behavioral Outcomes of Brain-Computer Interface Stroke Rehabilitation Using Machine Learning

The primary goal of this work was to apply data-driven machine learning regression to assess if resting state functional connectivity (rs-FC) could estimate measures of behavioral domains in stroke subjects who completed brain-computer interface (BCI) intervention for motor rehabilitation. The study cohort consisted of 20 chronic-stage stroke subjects exhibiting persistent upper-extremity motor deficits who received the intervention using a closed-loop neurofeedback BCI device. Over the course of this intervention, resting state functional MRI scans were collected at four distinct time points: namely, pre-intervention, mid-intervention, post-intervention and 1-month after completion of intervention. Behavioral assessments were administered outside the scanner at each time-point to collect objective measures such as the Action Research Arm Test, Nine-Hole Peg Test, and Barthel Index as well as subjective measures including the Stroke Impact Scale. The present analysis focused on neuroplasticity and behavioral outcomes measured across pre-intervention, post-intervention and 1-month post-intervention to study immediate and carry-over effects. Rs-FC, changes in rs-FC within the motor network and the behavioral measures at preceding stages were used as input features and behavioral measures and associated changes at succeeding stages were used as outcomes for machine-learning-based support vector regression (SVR) models. Potential clinical confounding factors such as age, gender, lesion hemisphere, and stroke severity were included as additional features in each of the regression models. Sequential forward feature selection procedure narrowed the search for important correlates. Behavioral outcomes at preceding time-points outperformed rs-FC-based correlates. Rs-FC and changes associated with bilateral primary motor areas were found to be important correlates of across several behavioral outcomes and were stable upon inclusion of clinical variables as well. NIH Stroke Scale and motor impairment severity were the most influential clinical variables. Comparatively, linear SVR models aided in evaluation of contribution of individual correlates and seed regions while non-linear SVR models achieved higher performance in prediction of behavioral outcomes.

Improving robotic stroke rehabilitation by incorporating neural intent detection: Preliminary results from a clinical trial

This paper presents the preliminary findings of a multi-year clinical study evaluating the effectiveness of adding a brain-machine interface (BMI) to the MAHI-Exo II, a robotic upper limb exoskeleton, for elbow flexion/extension rehabilitation in chronic stroke survivors. The BMI was used to trigger robot motion when movement intention was detected from subjects' neural signals, thus requiring that subjects be mentally engaged during robotic therapy. The first six subjects to complete the program have shown improvements in both Fugl-Meyer Upper-Extremity scores as well as in kinematic movement quality measures that relate to movement planning, coordination, and control. These results are encouraging and suggest that increasing subject engagement during therapy through the addition of an intent-detecting BMI enhances the effectiveness of standard robotic rehabilitation.

Mapping upper-limb motor performance after stroke - a novel method with utility for individualized motor training

Background

Chronic upper limb motor impairment is a common outcome of stroke. Therapeutic training can reduce motor impairment. Recently, a growing interest in evaluating motor training provided by robotic assistive devices has emerged. Robot-assisted therapy is attractive because it provides a means of increasing practice intensity without increasing the workload of physical therapists. However, movements practised through robotic assistive devices are commonly pre-defined and fixed across individuals. More optimal training may result from individualizing the selection of the trained movements based on the individual’s impairment profile. This requires quantitative assessment of the degree of the motor impairment prior to training, in relevant movement tasks. However, standard clinical measures for profiling motor impairment after stroke are often subjective and lack precision. We have developed a novel robot-mediated method for systematic and fine-grained mapping (or profiling) of individual performance across a wide range of planar arm reaching movements. Here we describe and demonstrate this mapping method and its utilization for individualized training. We also present a novel principle for the individualized selection of training movements based on the performance maps.

Methods and Results

To demonstrate the utility of our method we present examples of 2D performance maps produced from the kinetic and kinematics data of two individuals with stroke-related upper limb hemiparesis. The maps outline distinct regions of high motor impairment. The procedure of map-based selection of training movements and the change in motor performance following training is demonstrated for one participant.

Conclusions

The performance mapping method is feasible to produce (online or offline). The 2D maps are easy to interpret and to be utilized for selecting individual performance-based training. Different performance maps can be easily compared within and between individuals, which potentially has diagnostic utility.

Electronic supplementary material

The online version of this article (10.1186/s12984-017-0335-x) contains supplementary material, which is available to authorized users.

The Present and Future of Robotic Technology in Rehabilitation

Robotic technology designed to assist rehabilitation can potentially increase the efficiency of and accessibility to therapy by assisting therapists to provide consistent training for extended periods of time, and collecting data to assess progress. Automatization of therapy may enable many patients to be treated simultaneously and possibly even remotely, in the comfort of their own homes, through telerehabilitation. The data collected can be used to objectively assess performance and document compliance as well as progress. All of these characteristics can make therapists more efficient in treating larger numbers of patients. Most importantly for the patient, it can increase access to therapy which is often in high demand and rationed severely in today's fiscal climate. In recent years, many consumer grade low-cost and off-the-shelf devices have been adopted for use in therapy sessions and methods for increasing motivation and engagement have been integrated with them. This review paper outlines the effort devoted to the development and integration of robotic technology for rehabilitation.

Effects of Arm Weight Support Training to Promote Recovery of Upper Limb Function for Subacute Patients after Stroke with Different Levels of Arm Impairments

Purpose. The goal of this study was to investigate the effects of arm weight support training using the ArmeoSpring for subacute patients after stroke with different levels of hemiplegic arm impairments. Methods. 48 inpatients with subacute stroke, stratified into 3 groups from mild to severe upper extremity impairment, were engaged in ArmeoSpring training for 45 minutes daily, 5 days per week for 3 weeks, in addition to conventional rehabilitation. Evaluations were conducted at three measurement occasions: immediately before training (T1); immediately after training (T2); and at a 3-week follow-up (T3) by a blind rater. Results. Shoulder flexion active range of motion, Upper Extremity Scores in the Fugl-Meyer Assessment (FMA), and Vertical Catch had the greatest differences in gain scores for patients between severe and moderate impairments, whereas FMA Hand Scores had significant differences in gain scores between moderate and mild impairments. There was no significant change in muscle tone or hand-path ratios between T1, T2, and T3 within the groups. Conclusion. Arm weight support training is beneficial for subacute stroke patients with moderate to severe arm impairments, especially to improve vertical control such as shoulder flexion, and there were no adverse effects in muscle tone.

Does Shorter Rehabilitation Limit Potential Recovery Poststroke?

Objective. To examine retrospectively the recovery of patients engaged in robotic research during a 6- to 7-week course of inpatient rehabilitation. Because timing of the Interim evaluation at 31/2 weeks was comparable to the present length of inpatient stroke rehabilitation, the authors assessed whether significant gains in motor abilities occurred after the time when most stroke patients today are discharged home. Methods. Fifty-six inpatients with a single, unilateral stroke were randomly assigned to a robot therapy or robot exposure group. Therapists blinded to group assignment administered the Fugl-Meyer, Motor Status Score, and MRC motor power test. Results. Significant improvements in upper-limb motor abilities occurred throughout a period approximately twice the present length of stay in inpatient rehabilitation. However, in the latter half of this period, patients who received conventional therapy showed little improvement, whereas patients who received robot training plus conventional therapy continued to improve. Conclusion. Further opportunities for recovery after stroke are possible by extending intensive therapy beyond present inpatient rehabilitation stays.

Robot-Aided Neurorehabilitation: A Pediatric Robot for Ankle Rehabilitation

This paper presents the pediAnklebot, an impedance-controlled low-friction, backdriveable robotic device developed at the Massachusetts Institute of Technology that trains the ankle of neurologically impaired children of ages 6-10 years old. The design attempts to overcome the known limitations of the lower extremity robotics and the unknown difficulties of what constitutes an appropriate therapeutic interaction with children. The robot's pilot clinical evaluation is on-going and it incorporates our recent findings on the ankle sensorimotor control in neurologically intact subjects, namely the speed-accuracy tradeoff, the deviation from an ideally smooth ankle trajectory, and the reaction time. We used these concepts to develop the kinematic and kinetic performance metrics that guided the ankle therapy in a similar fashion that we have done for our upper extremity devices. Here we report on the use of the device in at least nine training sessions for three neurologically impaired children. Results demonstrated a statistically significant improvement in the performance metrics assessing explicit and implicit motor learning. Based on these initial results, we are confident that the device will become an effective tool that harnesses plasticity to guide habilitation during childhood.

Task Selection and Enriched Environments: A Functional Upper Extremity Training Program for Stroke Survivors

Functional tasks using real-life objects in an enriched environment provide a multidimensional approach to treatment. Functional tasks are therapeutic for stroke survivors, because they require the simultaneous use of motor control, cognition, visual perception, sensation, and motor planning. Therapists utilizing functional tasks as treatment modalities must also be multidimensional in their implementation. This article provides a systematic approach to guide therapists in developing a functional upper extremity training program for stroke survivors.

Robotic Technology and Stroke Rehabilitation: Translating Research into Practice

Research on the effectiveness of robotic therapy for the paretic upper limb after stroke has shown statistically significant reductions in motor impairment during both acute and chronic phases of recovery. Despite growing empirical support for this technology and a stronger focus on optimizing rehabilitation outcomes and productivity, there continues to be a disconnect between research and clinical practice. We review studies on the use of robot-aided neurorehabilitation for the paretic arm after stroke and discuss ways in which this technology may provide opportunities for intensive training that complement more conventional therapy methods.

Ottawa Panel Evidence-Based Clinical Practice Guidelines for Post-Stroke Rehabilitation

BACKGROUND AND PURPOSE

The purpose of this project was to create guidelines for 13 types of physical rehabilitation interventions used in the management of adult patients (>18 years of age) presenting with hemiplegia or hemiparesis following a single clinically identifiable ischemic or hemorrhagic cerebrovascular accident (CVA).

METHOD

Using Cochrane Collaboration methods, the Ottawa Methods Group identified and synthesized evidence from comparative controlled trials. The group then formed an expert panel, which developed a set of criteria for grading the strength of the evidence and the recommendation. Patient-important outcomes were determined through consensus, provided that these outcomes were assessed with a validated and reliable scale.

RESULTS

The Ottawa Panel developed 147 positive recommendations of clinical benefit concerning the use of different types of physical rehabilitation interventions involved in post-stroke rehabilitation.

DISCUSSION AND CONCLUSION

The Ottawa Panel recommends the use of therapeutic exercise, task-oriented training, biofeedback, gait training, balance training, constraint-induced movement therapy, treatment of shoulder subluxation, electrical stimulation, transcutaneous electrical nerve stimulation, therapeutic ultrasound, acupuncture, and intensity and organization of rehabilitation in the management of post stroke.

Motor Recovery Strategies After Stroke

Impaired motor function after stroke is a major cause of disability in young stroke survivors. The plasticity of the adult human brain provides opportunities to enhance traditional rehabilitation programs for these individuals. Younger stroke patients appear to have a greater ability to recover from stroke and are likely to benefit substantially from treatments that facilitate plasticity-mediated recovery. The use of new exercise treatments, such as constraint-induced movement therapy, robot-aided rehabilitation, and partial body weight supported treadmill training are being studied intensively and are likely to ultimately be incorporated into standard poststroke rehabilitation. Medications to enhance recovery, growth factors, and stem cells will also be components of rehabilitation for the young stroke survivor in the foreseeable future.

Advances in the Understanding and Treatment of Stroke Impairment Using Robotic Devices

The presence of robotic devices in rehabilitation centers is now becoming commonplace across the world, challenging heath care professionals to rethink treatment strategies for motor impairment in hemiparetic stroke patients. In this article, we will discuss some of the motivations for using these devices, review clinical outcomes following robotic-assisted training in both the upper and lower extremities, and detail how these devices can provide quantitative evaluations of function. We will also address the clinical issues that need to be considered when using robotic devices to treat stroke patients, and finally a vision of where this field is heading will be discussed.

A review of technological and clinical aspects of robot-aided rehabilitation of upper-extremity after stroke

Cerebrovascular accident (CVA) or stroke is one of the leading causes of disability and loss of motor function. Millions of people around the world are effected by it each year. Stroke results in disabled arm function. Restoration of arm function is essential to regaining activities of daily living (ADL). Along with traditional rehabilitation methods, robot-aided therapy has emerged in recent years. Robot-aided rehabilitation is more intensive, of longer duration and more repetitive. Using robots, repetitive dull exercises can turn into a more challenging and motivating tasks such as games. Besides, robots can provide a quantitative measure of the rehabilitation progress. This article overviews the terms used in robot-aided upper-limb rehabilitation. It continues by investigating the requirements for rehabilitation robots. Then the most outstanding works in robot-aided upper-limb rehabilitation and their control schemes have been investigated. The clinical outcomes of the built robots are also given that demonstrates the usability of these robots in real-life applications and their acceptance. This article summarizes a review done along with a research on the design, simulation and control of a robot for use in upper-limb rehabilitation after stroke. Implications for Rehabilitation Reviewing common terms in rehabilitation of upper limb using robots Reviewing rehabilitation robots built up to date Reviewing clinical outcomes of the mentioned rehabilitation robots.

Reaching Kinematics to Measure Motor Changes After Mental Practice in Stroke

OBJECTIVE

To examine mental practice (MP) efficacy using a new kinematics reaching model.

METHOD

This was a prepost, case series conducted at an outpatient rehabilitation hospital of 5 patients who experienced stroke >1 year before study entry (3 males; mean age = 52.6 +/- 15.4 years [range, 38-76 years]; mean time since stroke = 51.2 months [range, 13-126 months]) exhibiting upper limb hemiparesis on their dominant sides. Participants received 30-minute therapy sessions emphasizing activities of daily living (ADLs) using their affected arms, which occurred 2 days/week for 6 weeks. After therapy, participants received 30-minute MP sessions requiring MP of the ADLs. The main outcome measure was 3-D Motion Analysis (kinematics), in which patients performed 2 functional reaching tasks consisting of reaching and grasping a plastic cylinder positioned at either elbow height (reach out) or shoulder height (reach up). Dependent variables included horizontal reaching distance, hand velocity, elbow range of motion, and shoulder range of motion.

RESULTS

Prior to intervention, the mean horizontal reaching distance was 8.3 +/- 1.7 cm and 10.9 +/- 2.2 cm for the reach-up and reach-out tasks, respectively. Upon completion of the intervention, ability to reach up significantly improved to 9.9 +/- 1.6 cm (p <.001). Horizontal reach distance also improved during the reach-out task (11.7 +/- 2.2 cm, p = .366). No statistically significant change was observed in linear hand velocity. Patients also exhibited greater shoulder flexion and elbow extension during both the posttest reach-up and posttest reach-out tasks.

DISCUSSION AND CONCLUSION

Kinematics appears to offer a precise, objective way of quantifying MP-induced motor changes during ADL performance. MP appears to improve several aspects of affected arm reaching.

Home-based Computer Assisted Arm Rehabilitation (hCAAR) robotic device for upper limb exercise after stroke: results of a feasibility study in home setting

Background

Home-based robotic technologies may offer the possibility of self-directed upper limb exercise after stroke as a means of increasing the intensity of rehabilitation treatment. The current literature has a paucity of robotic devices that have been tested in a home environment. The aim of this research project was to evaluate a robotic device Home-based Computer Assisted Arm Rehabilitation (hCAAR) that can be used independently at home by stroke survivors with upper limb weakness.

Methods

hCAAR device comprises of a joystick handle moved by the weak upper limb to perform tasks on the computer screen. The device provides assistance to the movements depending on users ability. Nineteen participants (stroke survivors with upper limb weakness) were recruited. Outcome measures performed at baseline (A0), at end of 8-weeks of hCAAR use (A1) and 1 month after end of hCAAR use (A2) were: Optotrak kinematic variables, Fugl Meyer Upper Extremity motor subscale (FM-UE), Action Research Arm Test (ARAT), Medical Research Council (MRC) and Modified Ashworth Scale (MAS), Chedoke Arm and Hand Activity Inventory (CAHAI) and ABILHAND.

Results

Two participants were unable to use hCAAR: one due to severe paresis and the other due to personal problems. The remaining 17 participants were able to use the device independently in their home setting. No serious adverse events were reported. The median usage time was 433 minutes (IQR 250 – 791 min). A statistically significant improvement was observed in the kinematic and clinical outcomes at A1. The median gain in the scores at A1 were by: movement time 19%, path length 15% and jerk 19%, FM-UE 1 point, total MAS 1.5 point, total MRC 2 points, ARAT 3 points, CAHAI 5.5 points and ABILHAND 3 points. Three participants showed clinically significant improvement in all the clinical outcomes.

Conclusions

The hCAAR feasibility study is the first clinical study of its kind reported in the current literature; in this study, 17 participants used the robotic device independently for eight weeks in their own homes with minimal supervision from healthcare professionals. Statistically significant improvements were observed in the kinematic and clinical outcomes in the study.

Electronic supplementary material

The online version of this article (doi:10.1186/1743-0003-11-163) contains supplementary material, which is available to authorized users.

[Does upper limb robot-assisted rehabilitation contribute to improve the prognosis of post-stroke hemiparesis?]

INTRODUCTION

Upper limb robot-assisted rehabilitation is a novel physical treatment for neurological motor impairments. During the last decade, this rehabilitation option utilizing technological tools has been evaluated in hemiparetic patients, mostly after stroke.

STATE OF ART

Studies at acute and chronic stages suggested good tolerance and a significant and persistent reduction of motor impairment; a real impact on disability has been shown in acute/sub acute patients.

PERSPECTIVES

Improved access to rehabilitation robots and an optimal use will probably be associated with higher efficiency of rehabilitative work in the paretic upper limb.

CONCLUSIONS

Even if this treatment is still confined to a narrow circle of users, the device's biomechanical properties and clinical suggestions from the literature may show promise for the future of rehabilitation.

Training modalities in robot-mediated upper limb rehabilitation in stroke: a framework for classification based on a systematic review

Robot-mediated post-stroke therapy for the upper-extremity dates back to the 1990s. Since then, a number of robotic devices have become commercially available. There is clear evidence that robotic interventions improve upper limb motor scores and strength, but these improvements are often not transferred to performance of activities of daily living. We wish to better understand why. Our systematic review of 74 papers focuses on the targeted stage of recovery, the part of the limb trained, the different modalities used, and the effectiveness of each. The review shows that most of the studies so far focus on training of the proximal arm for chronic stroke patients. About the training modalities, studies typically refer to active, active-assisted and passive interaction. Robot-therapy in active assisted mode was associated with consistent improvements in arm function. More specifically, the use of HRI features stressing active contribution by the patient, such as EMG-modulated forces or a pushing force in combination with spring-damper guidance, may be beneficial.Our work also highlights that current literature frequently lacks information regarding the mechanism about the physical human-robot interaction (HRI). It is often unclear how the different modalities are implemented by different research groups (using different robots and platforms). In order to have a better and more reliable evidence of usefulness for these technologies, it is recommended that the HRI is better described and documented so that work of various teams can be considered in the same group and categories, allowing to infer for more suitable approaches. We propose a framework for categorisation of HRI modalities and features that will allow comparing their therapeutic benefits.

Human-adaptive control of series elastic actuators

Force-controlled series elastic actuators (SEAs) are the widely used components of novel physical human–robot interaction applications such as assistive and rehabilitation robotics. These systems are characterized by the presence of the “human in the loop” so that control response and stability depend on uncertain human dynamics. A common approach to guarantee stability is to use a passivity-based controller. Unfortunately, existing passivity-based controllers for SEAs do not define the performance of the force/torque loop. We propose a method to obtain predictable force/torque dynamics based on adaptive control and oversimplified human models. We propose a class of stable human-adaptive algorithms and experimentally show advantages of the proposed approach.

Current Trends in Robot-Assisted Upper-Limb Stroke Rehabilitation: Promoting Patient Engagement in Therapy

Stroke is one of the leading causes of long-term disability today; therefore, many research efforts are focused on designing maximally effective and efficient treatment methods. In particular, robotic stroke rehabilitation has received significant attention for upper-limb therapy due to its ability to provide high-intensity repetitive movement therapy with less effort than would be required for traditional methods. Recent research has focused on increasing patient engagement in therapy, which has been shown to be important for inducing neural plasticity to facilitate recovery. Robotic therapy devices enable unique methods for promoting patient engagement by providing assistance only as needed and by detecting patient movement intent to drive to the device. Use of these methods has demonstrated improvements in functional outcomes, but careful comparisons between methods remain to be done. Future work should include controlled clinical trials and comparisons of effectiveness of different methods for patients with different abilities and needs in order to inform future development of patient-specific therapeutic protocols.

Mechanisms of motor recovery in chronic and subacute stroke patients following a robot-aided training

The aim of this article is to propose a methodology for analyzing different recovery mechanisms in subacute and chronic patients through evaluation of biomechanical parameters. Twenty-five post-stroke subjects, eight subacute and seventeen chronic, participated in the study. A 2-DoF robotic system was used for upper limb training. Two clinical scales were used for assessment. Forces and velocities at the robot's end-effector during the execution of upper limb planar reaching movements were measured. Clinical outcome measures show a significant decrease in motor impairment after the treatment both in chronic and subacute patients (MSS-SE, p<0.001; FM, p<0.05). Movement velocity increases after the robot-aided treatment in both groups. Mean values of forces exerted by subacute patients are lower than those observed in chronic patients, both at the beginning and at the end of robotic treatment, as in the latter the pathological pattern is already structured. Our results demonstrate that the monitoring of the forces exerted on the end-effector during robot-aided treatment can identify the specific motor recovery mechanisms at different stages. If the pathological pattern is not yet structured, rehabilitative interventions should be addressed toward the use of motor re-learning procedures; on the other hand, if the force analysis shows a strong pathological pattern, mechanisms of compensation should be encouraged.

Pointing with the ankle: the speed-accuracy trade-off

This study investigated the trade-off between speed and accuracy in pointing movements with the ankle during goal-directed movements in dorsal-plantar (DP) and inversion-eversion (IE). Nine subjects completed a series of discrete pointing movements with the ankle between spatial targets of varying difficulty. Six different target sets were presented, with a range of task difficulty between 2.2 and 3.8 bits of information. Our results demonstrated that for visually evoked, visually guided discrete DP and IE ankle pointing movements, performance can be described by a linear function, as predicted by Fitts' law. These results support our ongoing effort to develop an adaptive algorithm employing the speed-accuracy trade-off concept to control our pediatric anklebot while delivering therapy for children with cerebral palsy.

Insights into upper limb kinematics and trunk control one year after task-related training in chronic post-stroke individuals

STUDY DESIGN

Randomized clinical trial.

INTRODUCTION

Long-term follow-up of training investigations involving post-stroke individuals can lead to advancing clinical decisions. Extended task-related training (TRT) effects on reaching with the impaired upper limb were evaluated, using a pre-test/posttest/follow-up design.

PURPOSE

One-year follow-up examinations analyzed whether improved shoulder and elbow motion were maintained following prolonged practice of the upper limb.

METHODS

Long-term kinematic analysis on 21 moderately impaired post-stroke participants (upper extremity Fugl-Meyer between 19 and 40/66), as well as results from standardized outcome measures performed on these patients and another 16 post-stroke participants.

RESULTS

Significant initial changes were maintained for kinematic shoulder and elbow motion, as well as functional measures. Compensatory reaching involving the trunk has been shown to be maintainable, but ultimately less efficient.

CONCLUSIONS

Training that involves a conscious decision to control the trunk led to the most improved functional performance, and may lead to ideal restorative strategies.

LEVEL OF EVIDENCE

2B.

Diffusion tensor and volumetric magnetic resonance imaging using an MR-compatible hand-induced robotic device suggests training-induced neuroplasticity in patients with chronic stroke

Stroke is the third leading cause of mortality and a frequent cause of long-term adult impairment. Improved strategies to enhance motor function in individuals with chronic disability from stroke are thus required. Post-stroke therapy may improve rehabilitation and reduce long-term disability; however, objective methods for evaluating the specific impact of rehabilitation are rare. Brain imaging studies on patients with chronic stroke have shown evidence for reorganization of areas showing functional plasticity after a stroke. In this study, we hypothesized that brain mapping using a novel magnetic resonance (MR)-compatible hand device in conjunction with state-of-the-art magnetic resonance imaging (MRI) can serve as a novel biomarker for brain plasticity induced by rehabilitative motor training in patients with chronic stroke. This hypothesis is based on the premises that robotic devices, by stimulating brain plasticity, can assist in restoring movement compromised by stroke-induced pathological changes in the brain and that these changes can then be monitored by advanced MRI. We serially examined 15 healthy controls and 4 patients with chronic stroke. We employed a combination of diffusion tensor imaging (DTI) and volumetric MRI using a 3-tesla (3T) MRI system using a 12-channel Siemens Tim coil and a novel MR-compatible hand-induced robotic device. DTI data revealed that the number of fibers and the average tract length significantly increased after 8 weeks of hand training by 110% and 64%, respectively (p<0.001). New corticospinal tract (CST) fibers projecting progressively closer to the motor cortex appeared during training. Volumetric data analysis showed a statistically significant increase in the cortical thickness of the ventral postcentral gyrus areas of patients after training relative to pre-training cortical thickness (p<0.001). We suggest that rehabilitation is possible for a longer period of time after stroke than previously thought, showing that structural plasticity is possible even after 6 months due to retained neuroplasticity. Our study is an example of personalized medicine using advanced neuroimaging methods in conjunction with robotics in the molecular medicine era.

fMRI as a molecular imaging procedure for the functional reorganization of motor systems in chronic stroke

Previous brain imaging studies suggest that stroke alters functional connectivity in motor execution networks. Moreover, current understanding of brain plasticity has led to new approaches in stroke rehabilitation. Recent studies showed a significant role of effective coupling of neuronal activity in the SMA (supplementary motor area) and M1 (primary motor cortex) network for motor outcome in patients after stroke. After a subcortical stroke, functional magnetic resonance imaging (fMRI) during movement reveals cortical reorganization that is associated with the recovery of function. The aim of the present study was to explore connectivity alterations within the motor-related areas combining motor fMRI with a novel MR-compatible hand-induced robotic device (MR_CHIROD) training. Patients completed training at home and underwent serial MR evaluation at baseline and after 8 weeks of training. Training at home consisted of squeezing a gel exercise ball with the paretic hand at ~75% of maximum strength for 1 h/day, 3 days/week. The fMRI analysis revealed alterations in M1, SMA, PMC (premotor cortex) and Cer (cerebellum) in both stroke patients and healthy controls after the training. Findings of the present study suggest that enhancement of SMA activity could benefit M1 dysfunction in stroke survivors. These results also indicate that connectivity alterations between motor areas might assist the counterbalance of a functionally abnormal M1 in chronic stroke survivors and possibly other patients with motor dysfunction.

Effects of the Alternate Combination of "Error-Enhancing" and "Active Assistive" Robot-Mediated Treatments on Stroke Patients

This paper aimed at investigating the effects of a novel robotic-aided rehabilitation treatment for the recovery of the upper limb related capabilities in chronic post stroke patients. Eighteen post-stroke patients were enrolled in a six-week therapy program and divided into two groups. They were all required to perform horizontal pointing movements both in the presence of a robot-generated divergent force field (DF) that pushed their hands proportional to the trajectory error and perpendicular to the direction of motion, and according to the typical active assistive (AA) approach used in robotic therapy. We used a crossover experimental paradigm where the two groups switched from one therapy treatment to the other. The hypothesis underlying this paper was that the use of the destabilizing scenario forced the patient to keep the end-point position as close as possible to the ideal path, hence requiring a more active control of the arm with respect to the AA approach. Our findings confirmed this hypothesis. In addition, when the DF treatment was provided in the first therapy cycle, patients also showed straighter and smoother paths during the subsequent AA therapy cycle, while this was not true in the opposite case. In conclusion, the results herein reported provide evidence that the use of an unstable DF field can lead to better recovery outcomes, and therefore it potentially more effective than solely active assistance therapy alone.

Robot-assisted upper limb rehabilitation in chronic stroke patients

The goal of this study is to evaluate the effects of upper limb robot-assisted treatment in chronic post-stroke patients using clinical outcome measures and kinematic parameters. Thirty-two chronic stroke patients participated in the study. Fugl-Meyer (FM) Assessment scale and Motricity Index (MI) were used for clinical assessment, and a set of kinematic parameters was computed. A significant decrease in motor impairment after the robotassisted treatment (FM p<0.001 and MI p<0.001) was found. Movement mean velocity (p<0.001) and accuracy (p<0.05) increased. Robotic treatment is effective to reduce motor impairment in chronic stroke patients. The exclusive use of clinical scales do not provide an exhaustive evaluation of effectiveness of treatment and our study suggests that kinematic parameters should be computed as well.

Rehabilitation robotics

This chapter focuses on rehabilitation robotics which can be used to augment the clinician's toolbox in order to deliver meaningful restorative therapy for an aging population, as well as on advances in orthotics to augment an individual's functional abilities beyond neurorestoration potential. The interest in rehabilitation robotics and orthotics is increasing steadily with marked growth in the last 10 years. This growth is understandable in view of the increased demand for caregivers and rehabilitation services escalating apace with the graying of the population. We provide an overview on improving function in people with a weak limb due to a neurological disorder who cannot properly control it to interact with the environment (orthotics); we then focus on tools to assist the clinician in promoting rehabilitation of an individual so that s/he can interact with the environment unassisted (rehabilitation robotics). We present a few clinical results occurring immediately poststroke as well as during the chronic phase that demonstrate superior gains for the upper extremity when employing rehabilitation robotics instead of usual care. These include the landmark VA-ROBOTICS multisite, randomized clinical study which demonstrates clinical gains for chronic stroke that go beyond usual care at no additional cost.

A comparative analysis of speed profile models for wrist pointing movements

Following two decades of design and clinical research on robot-mediated therapy for the shoulder and elbow, therapeutic robotic devices for other joints are being proposed: several research groups including ours have designed robots for the wrist, either to be used as stand-alone devices or in conjunction with shoulder and elbow devices. However, in contrast with robots for the shoulder and elbow which were able to take advantage of descriptive kinematic models developed in neuroscience for the past 30 years, design of wrist robots controllers cannot rely on similar prior art: wrist movement kinematics has been largely unexplored. This study aimed at examining speed profiles of fast, visually evoked, visually guided, target-directed human wrist pointing movements. One thousand three-hundred ninety-eight (1398) trials were recorded from seven unimpaired subjects who performed center-out flexion/extension and abduction/adduction wrist movements and fitted with 19 models previously proposed for describing reaching speed profiles. A nonlinear, least squares optimization procedure extracted parameters' sets that minimized error between experimental and reconstructed data. Models' performances were compared based on their ability to reconstruct experimental data. Results suggest that the support-bounded lognormal is the best model for speed profiles of fast, wrist pointing movements. Applications include design of control algorithms for therapeutic wrist robots and quantitative metrics of motor recovery.

Robot-aided sensorimotor arm training methods based on neurological rehabilitation principles in stroke and brain injury patients

We developed the upper extremity compound movements (UECM) rehabilitation training robot and designed straight-line paths tracking and circle paths tracking exercise based on neurological rehabilitation principles. Rehabilitative exercises should be on hand paths rather than on individual joints. robot can guide patients during forward reaching movements. The exterior oriented circle movement performed the coactivation of shoulder abductors with elbow extensors and the coactivation of shoulder adductors with elbow flexors at most of tracks against the stereotypic movement pattern in stroke and brain injury.

Design and implementation of a training strategy in chronic stroke with an arm robotic exoskeleton

The distinguishing features of active exoskeletons are the capability of guiding arm movement at the level of the full kinematic chain of the human arm, and training full 3D spatial movements. We have specifically developed a PD sliding mode control for upper limb rehabilitation with gain scheduling for providing "assistance as needed", according to the force capability of the patient, and an automatic measurement of the impaired arm joint torques, to evaluate the hypertonia associated to the movement during the execution of the training exercise. Two different training tasks in Virtual Reality were devised, that make use of the above control, and allow to make a performance based evaluation of patient's motor status. The PERCRO L-Exos (Light-Exoskeleton) was used to evaluate the proposed algorithms and training exercises in two clinical case studies of patients with chronic stroke, that performed 6 weeks of robotic assisted training. Clinical evaluation (Fugl-Meyer Scale, Modified Ashworth Scale, Bimanual Activity Test) was conducted before and after treatment and compared to the scores and the quantitative indices, such as task time, position/joint error and resistance torques, associated to the training exercises.

Adaptive regulation of assistance 'as needed' in robot-assisted motor skill learning and neuro-rehabilitation

We propose a general adaptive procedure to select the appropriate degree of assistance based on a Bayesian mechanism used to estimate psychophysical thresholds. This technique does not need an accurate model of learning and recovery processes. This procedure is validated in the context of a motor skill learning problem (control of a virtual object), in which the controller is used to gradually increase task difficulty as learning proceeds. These automatic adjustments of task difficulty or the degree of assistance can be used to promote not only motor skill learning but also neuromotor recovery.