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

Effects of robot-assisted therapy on upper limb recovery after stroke: a systematic review

OBJECTIVE

The aim of the study was to present a systematic review of studies that investigate the effects of robot-assisted therapy on motor and functional recovery in patients with stroke.

METHODS

A database of articles published up to October 2006 was compiled using the following Medline key words: cerebral vascular accident, cerebral vascular disorders, stroke, paresis, hemiplegia, upper extremity, arm, and robot. References listed in relevant publications were also screened. Studies that satisfied the following selection criteria were included: (1) patients were diagnosed with cerebral vascular accident; (2) effects of robot-assisted therapy for the upper limb were investigated; (3) the outcome was measured in terms of motor and/or functional recovery of the upper paretic limb; and (4) the study was a randomized clinical trial (RCT). For each outcome measure, the estimated effect size (ES) and the summary effect size (SES) expressed in standard deviation units (SDU) were calculated for motor recovery and functional ability (activities of daily living [ADLs]) using fixed and random effect models. Ten studies, involving 218 patients, were included in the synthesis. Their methodological quality ranged from 4 to 8 on a (maximum) 10-point scale.

RESULTS

Meta-analysis showed a nonsignificant heterogeneous SES in terms of upper limb motor recovery. Sensitivity analysis of studies involving only shoulder-elbow robotics subsequently demonstrated a significant homogeneous SES for motor recovery of the upper paretic limb. No significant SES was observed for functional ability (ADL).

CONCLUSION

As a result of marked heterogeneity in studies between distal and proximal arm robotics, no overall significant effect in favor of robot-assisted therapy was found in the present meta-analysis. However, subsequent sensitivity analysis showed a significant improvement in upper limb motor function after stroke for upper arm robotics. No significant improvement was found in ADL function. However, the administered ADL scales in the reviewed studies fail to adequately reflect recovery of the paretic upper limb, whereas valid instruments that measure outcome of dexterity of the paretic arm and hand are mostly absent in selected studies. Future research into the effects of robot-assisted therapy should therefore distinguish between upper and lower robotics arm training and concentrate on kinematical analysis to differentiate between genuine upper limb motor recovery and functional recovery due to compensation strategies by proximal control of the trunk and upper limb.

Design and Characterization of Hand Module for Whole-Arm Rehabilitation Following Stroke

In 1991, a novel robot named MIT-MANUS was introduced as a test bed to study the potential of using robots to assist in and quantify the neurorehabilitation of motor function. It introduced a new modality of therapy, offering a highly backdrivable experience with a soft and stable feel for the user. MIT-MANUS proved an excellent fit for shoulder and elbow rehabilitation in stroke patients, showing a reduction of impairment in clinical trials with well over 300 stroke patients. The greatest impairment reduction was observed in the group of muscles exercised. This suggests a need for additional robots to rehabilitate other target areas of the body. Previous work has expanded the planar MIT-MANUS to include an antigravity robot for shoulder and elbow, and a wrist robot. In this paper we present the "missing link": a hand robot. It consists of a single-degree-of-freedom (DOF) mechanism in a novel statorless configuration, which enables rehabilitation of grasping. The system uses the kinematic configuration of a double crank and slider where the members are linked to stator and rotor; a free base motor, i.e., a motor having two rotors that are free to rotate instead of a fixed stator and a single rotatable rotor (dual-rotor statorless motor). A cylindrical structure, made of six panels and driven by the relative rotation of the rotors, is able to increase its radius linearly, moving or guiding the hand of the patients during grasping. This module completes our development of robots for the upper extremity, yielding for the first time a whole-arm rehabilitation experience. In this paper, we will discuss in detail the design and characterization of the device.

Changing motor synergies in chronic stroke

Synergies are thought to be the building blocks of vertebrate movements. The inability to execute synergies in properly timed and graded fashion precludes adequate functional motor performance. In humans with stroke, abnormal synergies are a sign of persistent neurological deficit and result in loss of independent joint control, which disrupts the kinematics of voluntary movements. This study aimed at characterizing training-related changes in synergies apparent from movement kinematics and, specifically, at assessing: 1) the extent to which they characterize recovery and 2) whether they follow a pattern of augmentation of existing abnormal synergies or, conversely, are characterized by a process of extinction of the abnormal synergies. We used a robotic therapy device to train and analyze paretic arm movements of 117 persons with chronic stroke. In a task for which they received no training, subjects were better able to draw circles by discharge. Comparison with performance at admission on kinematic robot-derived metrics showed that subjects were able to execute shoulder and elbow joint movements with significantly greater independence or, using the clinical description, with more isolated control. We argue that the changes we observed in the proposed metrics reflect changes in synergies. We show that they capture a significant portion of the recovery process, as measured by the clinical Fugl-Meyer scale. A process of "tuning" or augmentation of existing abnormal synergies, not extinction of the abnormal synergies, appears to underlie recovery.

Stochastic estimation of arm mechanical impedance during robotic stroke rehabilitation

This paper presents a stochastic method to estimate the multijoint mechanical impedance of the human arm suitable for use in a clinical setting, e.g., with persons with stroke undergoing robotic rehabilitation for a paralyzed arm. In this context, special circumstances such as hypertonicity and tissue atrophy due to disuse of the hemiplegic limb must be considered. A low-impedance robot was used to bring the upper limb of a stroke patient to a test location, generate force perturbations, and measure the resulting motion. Methods were developed to compensate for input signal coupling at low frequencies apparently due to human-machine interaction dynamics. Data was analyzed by spectral procedures that make no assumption about model structure. The method was validated by measuring simple mechanical hardware and results from a patient's hemiplegic arm are presented.

Electromyography-Controlled Exoskeletal Upper-Limb–Powered Orthosis for Exercise Training After Stroke

OBJECTIVE

Robot-assisted exercise shows promise as a means of providing exercise therapy for weakness that results from stroke or other neurological conditions. Exoskeletal or "wearable" robots can, in principle, provide therapeutic exercise and/or function as powered orthoses to help compensate for chronic weakness. We describe a novel electromyography (EMG)-controlled exoskeletal robotic brace for the elbow (the active joint brace) and the results of a pilot study conducted using this brace for exercise training in individuals with chronic hemiparesis after stroke.

DESIGN

Eight stroke survivors with severe chronic hemiparesis were enrolled in this pilot study. One subject withdrew from the study because of scheduling conflicts. A second subject was unable to participate in the training protocol because of insufficient surface EMG activity to control the active joint brace. The six remaining subjects each underwent 18 hrs of exercise training using the device for a period of 6 wks. Outcome measures included the upper-extremity component of the Fugl-Meyer scale and the modified Ashworth scale of muscle hypertonicity.

RESULTS

Analysis revealed that the mean upper-extremity component of the Fugl-Meyer scale increased from 15.5 (SD 3.88) to 19 (SD 3.95) (P = 0.04) at the conclusion of training for the six subjects who completed training. Combined (summated) modified Ashworth scale for the elbow flexors and extensors improved from 4.67 (+/-1.2 SD) to 2.33 (+/-0.653 SD) (P = 0.009) and improved for the entire upper limb as well. All subjects tolerated the device, and no complications occurred.

CONCLUSION

EMG-controlled powered elbow orthoses can be successfully controlled by severely impaired hemiparetic stroke survivors. This technique shows promise as a new modality for assisted exercise training after stroke.

Emerging Therapies in Stroke Rehabilitation

Traditionally, practitioners of stroke rehabilitation are taught that benefits of rehabilitation are achieved primarily through training patients in new techniques to compensate for impairments, and that neurological recovery is predominantly spontaneous in nature. Recent animal and human experiments have, however, indicated that the adult brain is capable of reorganisation and the term plasticity has been coined to describe this ability. Furthermore, it has been shown that cerebral reorganisation is use-dependent and can be manipulated via appropriate stimuli. This has resulted in a paradigm shift in the way stroke survivors should be rehabilitated and also given rise to several novel rehabilitation techniques. Key words: Rehabilitation, Stroke

Activity-based therapies

Therapeutic activity is a mainstay of clinical neurorehabilitation, but is typically unstructured and directed at compensation rather than restoration of central nervous system function. Newer activity-based therapies (ABTs) are in early stages of development and testing. The ABTs attempt to restore function via standardized therapeutic activity based on principles of experimental psychology, exercise physiology, and neuroscience. Three of the best developed ABTs are constraint-induced therapy, robotic therapy directed at the hemiplegic arm, and treadmill training techniques aimed at improving gait in persons with stroke and spinal cord injury. These treatments appear effective in improving arm function and gait, but they have not yet been clearly demonstrated to be more effective than equal amounts of traditional techniques. Resistance training is clearly demonstrated to improve strength in persons with stroke and brain injury, and most studies show that it does not increase hypertonia. Clinical trials of ABTs face several methodological challenges. These challenges include defining dosage, standardizing treatment parameters across subjects and within treatment sessions, and determining what constitutes clinically significant treatment effects. The long-term goal is to develop prescriptive ABT, where specific activities are proven to treat specific motor system disorders. Activity-based therapies are not a cure, but are likely to play an important role in future treatment cocktails for stroke and spinal cord injury.

Sprouting, regeneration and circuit formation in the injured spinal cord: factors and activity

Central nervous system (CNS) injuries are particularly traumatic, owing to the limited capabilities of the mammalian CNS for repair. Nevertheless, functional recovery is observed in patients and experimental animals, but the degree of recovery is variable. We review the crucial characteristics of mammalian spinal cord function, tract development, injury and the current experimental therapeutic approaches for repair. Regenerative or compensatory growth of neurites and the formation of new, functional circuits require spontaneous and experimental reactivation of developmental mechanisms, suppression of the growth-inhibitory properties of the adult CNS tissue and specific targeted activation of new connections by rehabilitative training.

A novel robot training system designed to supplement upper limb physiotherapy of patients with spastic hemiparesis

Spasticity is velocity and acceleration dependent, and it is therefore important to execute physiotherapeutic exercises at a relatively low and constant velocity. This can be more accurately managed by a robot than by a person when such exercises are administered continuously for more than 15-20 min. The purpose of this project was to construct a robot-mediated system that could support upper limb physiotherapy of patients with spastic hemiparesis. The system, unlike any known robotic therapeutic system, uses unmodified industrial robots to carry out passive physiotherapy on the upper limb (including the movements of the shoulder and the elbow). An initial trial was executed in order to assess its safety and to gain experience of the robot-mediated therapy. Four healthy subjects and eight patients with spastic hemiparesis were included. Each subject received 30-min-long robotic physiotherapy sessions over 20 consecutive workdays. The 12 participants received, in total, 240 robot-mediated physiotherapeutic sessions. No dangerous situation or considerable technical problem occurred; the robots executed the therapy programme as intended. Investigation of the effectiveness of this kind of therapy was not an aim of this initial trial; however, the patients' clinical status was followed and some favourable changes were found regarding the spasticity of elbow flexors and shoulder abductors. According to the experiences of the first clinical investigation, the programming interface and the mechanical interface device between the patient and the robots had been improved. A controlled clinical study is under way to assess the effectiveness of the REHAROB movement therapy.

Therapeutic Robotics: A Technology Push: Stroke rehabilitation is being aided by robots that guide movement of shoulders and elbows, wrists, hands, arms and ankles to significantly improve recovery of patients

In this paper, we present a retrospective and chronological review of our efforts to revolutionize the way physical medicine is practiced by developing and deploying therapeutic robots. We present a sample of our clinical results with well over 300 stroke patients, both inpatients and outpatients, proving that movement therapy has a measurable and significant impact on recovery following brain injury. Bolstered by this result, we embarked on a two-pronged approach: 1) to determine what constitutes best therapy practice and 2) to develop additional therapeutic robots. We review our robots developed over the past 15 years and their unique characteristics. All are configured both to deliver reproducible therapy but also to measure outcomes with minimal encumbrance, thus providing critical measurement tools to help unravel the key question posed under the first prong: what constitutes "best practice"? We believe that a "gym" of robots like these will become a central feature of physical medicine and the rehabilitation clinic within the next ten years.

Comparison of the Action Research Arm Test and the Fugl-Meyer Assessment as Measures of Upper-Extremity Motor Weakness After Stroke

OBJECTIVE

To assess the relative responsiveness of 2 commonly used upper-extremity motor scales, the Action Research Arm Test (ARAT) and the Fugl-Meyer Assessment (FMA), in evaluating recovery of upper-extremity function after an acute stroke in patients undergoing inpatient rehabilitation.

DESIGN

Prospective.

SETTING

An acute stroke rehabilitation unit.

PARTICIPANTS

One hundred four consecutive admissions (43 men, 61 women; mean age +/- standard deviation, 72+/-13y) to a rehabilitation unit 16+/-9 days after acute stroke.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The following assessments were completed within 72 hours of admission and 24 hours before discharge: ARAT, upper-extremity motor domain of the FMA, National Institutes of Health Stroke Scale, FIM instrument total score, and FIM activities of daily living (FIM-ADL) subscore.

RESULTS

The Spearman rank correlation statistic indicated that the 2 upper-limb motor scales (ARAT, FMA) correlated highly with one another, both on admission (rho = .77, P < .001) and on discharge (rho = .87, P < .001). The mean change in score from admission to discharge was 10+/-15 for the ARAT and 10+/-13 for the FMA motor score. The responsiveness to change as measured by the standard response mean was .68 for the ARAT and .74 for the FMA motor score. The Spearman rank correlation of each upper-limb motor scale with the FIM-ADL at the time of admission was as follows: ARAT, rho equal to .32 (P < .001) and FMA motor score, rho equal to .54 (P < .001).

CONCLUSIONS

Both the FMA motor score and the ARAT were equally sensitive to change during inpatient acute rehabilitation and could be routinely used to measure recovery of upper-extremity motor function.

Robot-assisted reaching exercise promotes arm movement recovery in chronic hemiparetic stroke: a randomized controlled pilot study

Background and purpose

Providing active assistance to complete desired arm movements is a common technique in upper extremity rehabilitation after stroke. Such active assistance may improve recovery by affecting somatosensory input, motor planning, spasticity or soft tissue properties, but it is labor intensive and has not been validated in controlled trials. The purpose of this study was to investigate the effects of robotically administered active-assistive exercise and compare those with free reaching voluntary exercise in improving arm movement ability after chronic stroke.

Methods

Nineteen individuals at least one year post-stroke were randomized into one of two groups. One group performed 24 sessions of active-assistive reaching exercise with a simple robotic device, while a second group performed a task-matched amount of unassisted reaching. The main outcome measures were range and speed of supported arm movement, range, straightness and smoothness of unsupported reaching, and the Rancho Los Amigos Functional Test of Upper Extremity Function.

Results and discussion

There were significant improvements with training for range of motion and velocity of supported reaching, straightness of unsupported reaching, and functional movement ability. These improvements were not significantly different between the two training groups. The group that performed unassisted reaching exercise improved the smoothness of their reaching movements more than the robot-assisted group.

Conclusion

Improvements with both forms of exercise confirmed that repeated, task-related voluntary activation of the damaged motor system is a key stimulus to motor recovery following chronic stroke. Robotically assisting in reaching successfully improved arm movement ability, although it did not provide any detectable, additional value beyond the movement practice that occurred concurrently with it. The inability to detect any additional value of robot-assisted reaching may have been due to this pilot study's limited sample size, the specific diagnoses of the participants, or the inclusion of only individuals with chronic stroke.

Robot-aided intensive training in post-stroke recovery

The successful motor rehabilitation of stroke patients requires an intensive and task-specific therapy approach. The plasticity of the adult human brain provides opportunities to enhance traditional rehabilitation programs for these individuals. Intensive robot-aided sensorimotor training may have a positive effect on reducing impairment and disability and increasing reorganization of the adult brain. This approach may therefore efficaciously complement standard post-stroke multidisciplinary programs as shown by recent experimental trials.

A community-based upper-extremity group exercise program improves motor function and performance of functional activities in chronic stroke: a randomized controlled trial

OBJECTIVE

To assess the effects of a community-based exercise program on motor recovery and functional abilities of the paretic upper extremity in persons with chronic stroke.

DESIGN

Randomized controlled trial.

SETTING

Rehabilitation research laboratory and a community hall.

PARTICIPANTS

A sample of 63 people (> or =50y) with chronic deficits resulting from stroke (onset > or =1y).

INTERVENTIONS

The arm group underwent an exercise program designed to improve upper-extremity function (1h/session, 3 sessions/wk for 19wk). The leg group underwent a lower-extremity exercise program.

MAIN OUTCOME MEASURES

The Wolf Motor Function Test (WMFT), Fugl-Meyer Assessment (FMA), hand-held dynamometry (grip strength), and the Motor Activity Log.

RESULTS

Multivariate analysis showed a significant group by time interaction (Wilks lambda=.726, P=.017), indicating that overall, the arm group had significantly more improvement than the leg group. Post hoc analysis demonstrated that gains in WMFT (functional ability) (P=.001) and FMA (P=.001) scores were significantly higher in the arm group. The amount of improvement was comparable to other novel treatment approaches such as constraint-induced movement therapy or robot-aided exercise training previously reported in chronic stroke. Participants with moderate arm impairment benefited more from the program.

CONCLUSIONS

The pilot study showed that a community-based exercise program can improve upper-extremity function in persons with chronic stroke. This outcome justifies a larger clinical trial to further assess efficacy and cost effectiveness.

Acupuncture for upper-extremity rehabilitation in chronic stroke: a randomized sham-controlled study

OBJECTIVE

To compare the effects of traditional Chinese acupuncture with sham acupuncture on upper-extremity (UE) function and quality of life (QOL) in patients with chronic hemiparesis from stroke.

DESIGN

A prospective, sham-controlled, randomized controlled trial (RCT).

SETTING

Patients recruited through a hospital stroke rehabilitation program.

PARTICIPANTS

Thirty-three subjects who incurred a stroke 0.8 to 24 years previously and had moderate to severe UE functional impairment.

INTERVENTIONS

Active acupuncture tailored to traditional Chinese medicine diagnoses, including electroacupuncture, or sham acupuncture. Up to 20 treatment sessions (mean, 16.9) over a mean of 10.5 weeks.

MAIN OUTCOME MEASURES

UE motor function, spasticity, grip strength, range of motion (ROM), activities of daily living, QOL, and mood. All outcomes were measured at baseline and after treatment.

RESULTS

Intention-to-treat (ITT) analyses found no statistically significant differences in outcomes between active and sham acupuncture groups. Analyses of protocol-compliant subjects revealed significant improvement in wrist spasticity (P<.01) and both wrist (P<.01) and shoulder (P<.01) ROM in the active acupuncture group, and improvement trends in UE motor function (P=.09) and digit ROM (P=.06).

CONCLUSIONS

Based on ITT analyses, we conclude that acupuncture does not improve UE function or QOL in patients with chronic stroke symptoms. However, gains in UE function observed in protocol-compliant subjects suggest traditional Chinese acupuncture may help patients with chronic stroke symptoms. These results must be interpreted cautiously because of small sample sizes and multiple, unadjusted, post hoc comparisons. A larger, more definitive RCT using a similar design is feasible and warranted.

Robotics and other devices in the treatment of patients recovering from stroke

Stroke is the leading cause of permanent disability in the United States despite advances in prevention and novel interventional treatments. Randomized controlled studies have demonstrated the effectiveness of specialized post-stroke rehabilitation units, but administrative orders have severely limited the length of stay, so novel approaches to the treatment of recovery need to be tested in outpatients. Although the mechanisms of stroke recovery depend on multiple factors, a number of techniques that concentrate on enhanced exercise of the paralyzed limb have demonstrated effectiveness in reducing the motor impairment. For example, interactive robotic devices are new tools for therapists to deliver enhanced sensorimotor training for the paralyzed upper limb, which can potentially improve patient outcome and increase patient productivity. New data support the idea that for some post-stroke patients and for some aspects of training-induced recovery, timing of the training may be less important than the quality and intensity of the training. The positive outcome that resulted in the interactive robotic trials contrasts with the failure to find a beneficial result in trials that used a noninteractive device that delivered continuous passive motion only. New pilot data from novel devices to move the wrist demonstrate benefit and suggest that successive improvement of the function of the arm progressing to the distal muscles may eventually lead to significant disability reduction. These data from robotic trials continue to contribute to the emerging scientific basis of neuro-rehabilitation.

Customized interactive robotic treatment for stroke: EMG-triggered therapy

A system for electromyographic (EMG) triggering of robot-assisted therapy (dubbed the EMG game) for stroke patients is presented. The onset of a patient's attempt to move is detected by monitoring EMG in selected muscles, whereupon the robot assists her or him to perform point-to-point movements in a horizontal plane. Besides delivering customized robot-assisted therapy, the system can record signals that may be useful to better understand the process of recovery from stroke. Preliminary experiments aimed at testing the proposed system and gaining insight into the potential of EMG-triggered, robot-assisted therapy are reported.

Effects of mental practice on affected limb use and function in chronic stroke

OBJECTIVE

To determine the efficacy of a mental practice (MP) protocol in increasing the function and use of the more affected limb in stroke patients.

DESIGN

Randomized, controlled, multiple baseline, pre-post, case series.

SETTING

Outpatient rehabilitation hospital.

PARTICIPANTS

Eleven patients who had a stroke more than 1 year before study entry (9 men; mean age, 62.3+/-5.1 y; range, 53-71 y; mean time since stroke, 23.8 mo; range, 15-48 mo; 10 strokes exhibiting upper-limb hemiparesis on the dominant side) and who exhibited affected arm hemiparesis and nonuse.

INTERVENTION

All patients received 30-minute therapy sessions 2 days a week for 6 weeks. The sessions emphasized activities of daily living (ADLs): 6 subjects randomly assigned to the MP condition concurrently received sessions requiring daily MP of the ADLs; 5 subjects (control group) received an intervention consisting of relaxation techniques.

MAIN OUTCOME MEASURES

The Motor Activity Log and Action Research Arm (ARA) test.

RESULTS

Affected limb use as rated by MP patients and their caregivers increased (1.55, 1.66, respectively), as did patient and caregiver ratings of quality of movement (2.33, 2.15, respectively) and ARA scores (10.7). In contrast, the controls showed nominal increases in the amount they used their affected limb and in limb function. A Wilcoxon test on the ARA scores revealed significantly ( P =.004) greater changes in the MP group's scores.

CONCLUSIONS

Participation in an MP protocol may increase a stroke patient's use of his/her more affected limb. Data further support that the protocol resulted in correlative, MP-induced, motor function improvements. The mechanisms whereby MP increases affected arm use are unknown. Perhaps using the more affected limb becomes more salient through MP, or perhaps motor schema are altered during MP to integrate limb use.

Robotics and other devices in the treatment of patients recovering from stroke

Stroke is the leading cause of permanent disability in the United States despite advances in prevention and novel interventional treatments. Randomized controlled studies have demonstrated the effectiveness of specialized post-stroke rehabilitation units, but administrative orders have severely limited the length of stay, so novel approaches to the treatment of recovery need to be tested in outpatients. Although the mechanisms of stroke recovery depend on multiple factors, a number of techniques that concentrate on enhanced exercise of the paralyzed limb have demonstrated effectiveness in reducing the motor impairment. For example, interactive robotic devices are new tools for therapists to deliver enhanced sensorimotor training for the paralyzed upper limb, which can potentially improve patient outcome and increase their productivity. New data support the idea that for some post-stroke patients and for some aspects of training-induced recovery, timing of the training may be less important than the quality and intensity of the training. The positive outcome that resulted in the interactive robotic trials contrasts with the failure to find a beneficial result in trials that used a noninteractive device that delivered continuous passive motion only. New pilot data from novel devices to move the wrist demonstrate benefit and suggest that successive improvement of the function of the arm progressing to the distal muscles may eventually lead to significant disability reduction. These data from robotic trials continue to contribute to the emerging scientific basis of neuro-rehabilitation.

Rehabilitation robotics: pilot trial of a spatial extension for MIT-Manus

BACKGROUND: Previous results with the planar robot MIT-MANUS demonstrated positive benefits in trials with over 250 stroke patients. Consistent with motor learning, the positive effects did not generalize to other muscle groups or limb segments. Therefore we are designing a new class of robots to exercise other muscle groups or limb segments. This paper presents basic engineering aspects of a novel robotic module that extends our approach to anti-gravity movements out of the horizontal plane and a pilot study with 10 outpatients. Patients were trained during the initial six-weeks with the planar module (i.e., performance-based training limited to horizontal movements with gravity compensation). This training was followed by six-weeks of robotic therapy that focused on performing vertical arm movements against gravity. The 12-week protocol includes three one-hour robot therapy sessions per week (total 36 robot treatment sessions). RESULTS: Pilot study demonstrated that the protocol was safe and well tolerated with no patient presenting any adverse effect. Consistent with our past experience with persons with chronic strokes, there was a statistically significant reduction in tone measurement from admission to discharge of performance-based planar robot therapy and we have not observed increases in muscle tone or spasticity during the anti-gravity training protocol. Pilot results showed also a reduction in shoulder-elbow impairment following planar horizontal training. Furthermore, it suggested an additional reduction in shoulder-elbow impairment following the anti-gravity training. CONCLUSION: Our clinical experiments have focused on a fundamental question of whether task specific robotic training influences brain recovery. To date several studies demonstrate that in mature and damaged nervous systems, nurture indeed has an effect on nature. The improved recovery is most pronounced in the trained limb segments. We have now embarked on experiments that test whether we can continue to influence recovery, long after the acute insult, with a novel class of spatial robotic devices. This pilot results support the pursuit of further clinical trials to test efficacy and the pursuit of optimal therapy following brain injury.

Brain plasticity in health and disease

Research during the last decades has greatly increased our understanding of brain plasticity, i.e. how neuronal circuits can be modified by experience, learning and in response to brain lesions. Currently available neuroimaging techniques that make it possible to study the function of the human brain in vivo have had an important impact. Cross-modal plasticity during development is demonstrated by cortical reorganization in blind or deaf children. Early musical training has lasting effects in shaping the brain. Albeit the plasticity is largest during childhood, the adult brain retains a capacity for functional and structural reorganization that earlier has been underestimated. Recent research on Huntington's disease has revealed the possibility of environmental interaction even with dominant genes. Scientifically based training methods are now being applied in rehabilitation of patients after stroke and trauma, and in the sensory retraining techniques currently applied in the treatment of focal hand dystonia as well as in sensory re-education after nerve repair in hand surgery. There is evidence that frequent participation in challenging and stimulating activities is associated with reduced cognitive decline during aging. The current concept of brain plasticity has wide implication for areas outside neuroscience and for all human life.