Evaluation of robotic training forces that either enhance or reduce error in chronic hemiparetic stroke survivors (original) (raw)
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Robot training with vector fields based on stroke survivors' individual movement statistics
IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society, 2017
The wide variation in upper extremity motor impairments among stroke survivors necessitates more intelligent methods of customized therapy. However, current strategies for characterizing individual motor impairments are limited by the use of traditional clinical assessments (e.g. Fugl-Meyer) and simple engineering metrics (e.g. goal-directed performance). Our overall approach is to statistically identify the range of volitional movement capabilities, and then apply a robot-applied force vector field intervention that encourages under-expressed movements. We investigated whether explorative training with such customized force fields would improve stroke survivors' (n = 11) movement patterns in comparison to a control group that trained without forces (n = 11). Force and Control groups increased Fugl-Meyer UE scores (average of 1.0 and 1.1, respectively), which is not considered clinically meaningful. Interestingly, participants from both groups demonstrated dramatic increases in ...
The First IEEE/RAS-EMBS International Conference on Biomedical Robotics and Biomechatronics, 2006. BioRob 2006., 2006
We investigated whether robot-based training with a four degrees-of-freedom actuated device, the ARM Guide, would result in significant gains in arm movement ability of stroke survivors. Specifically, we sought to determine if specific trained tasks in a limited area of the workspace would transfer to gains in performance of different tasks and movement in untrained regions of the workspace. Subjects with chronic hemiparesis participated in an eight week training protocol and were randomized into one of three training groups: guided force training with the robotic device (N=7), free reaching (N=7), and a conventional occupational therapy group (N=7). Outcome measures include free reaching distance and observations of functional task performance from three clinical scales. Results indicated that all three training methods induced at least some transferable motor learning demonstrated in the functional tasks and in free reaching to a target that was outside of the trained workspace. We report here on our interm findings regarding the generalization of robot-assisted learning.
Robot-assisted movement training for the stroke-impaired arm: Does it matter what the robot does?
The Journal of Rehabilitation Research and Development, 2006
Robot-assisted movement training improves arm movement ability following acute and chronic stroke. Such training involves two interacting processes: the patient trying to move and the robot applying forces to the patient's arm. A fundamental principle of motor learning is that movement practice improves motor function; the role of applied robotic forces in improving motor function is still unclear. This article reviews our work addressing this question. Our pilot study using the Assisted Rehabilitation and Measurement (ARM) Guide, a linear robotic trainer, found that mechanically assisted reaching improved motor recovery similar to unassisted reaching practice. This finding is inconclusive because of the small sample size (n = 19), but suggest that future studies should carefully control the amount of voluntary movement practice delivered to justify the use of robotic forces. We are optimistic that robotic forces will ultimately show additional therapeutic benefits when coupled with movement practice. We justify this optimism here by comparing results from the ARM Guide and the Mirror Image Movement Enabler robotic trainer. This comparison suggests that requiring a patient to generate specific patterns of force before allowing movement is more effective than mechanically completing movements for the patient. We describe the engineering implementation of this "guided-force training" algorithm.
IEEE Transactions on Neural Systems and Rehabilitation Engineering, 2012
Both the American Heart Association and the VA/DoD endorse upper-extremity robot-mediated rehabilitation therapy for stroke care. However, we do not know yet how to optimize therapy for a particular patient's needs. Here, we explore whether we must train patients for each functional task that they must perform during their activities of daily living or alternatively capacitate patients to perform a class of tasks and have therapists assist them later in translating the observed gains into activities of daily living. The former implies that motor adaptation is a better model for motor recovery. The latter implies that motor learning (which allows for generalization) is a better model for motor recovery. We quantified trained and untrained movements performed by 158 recovering stroke patients via 13 metrics, including movement smoothness and submovements.
2012
Many exercise protocols for robot therapy are designed to adjust their degree of difficulty in order to maintain a constant challenge level. A simple way to do this is to design exercises that consist of a variable number of sub-movements in different directions-task difficulty is determined by the number of sub-movements. But, how does recovery proceed in these tasks, and how to regulate the magnitude of the assistance provided by the robot in this case? Here we focus on a simple task in which subjects had to complete a square figure. At every trial, an adaptive regulator selects the appropriate degree of robot assistance needed to complete the entire figure. We tested this protocol with four severely impaired stroke survivors during a multisession study. Robotic training succeeded-the controller gradually reduced the degree of assistance while performance remained constant, suggesting that in fact recovery took place. We used a dynamic model of the recovery process to further analyze the effects of the assistive force and the temporal evolution of the subjects' voluntary control. The model provided an excellent fitting of the subjects' performance and revealed that magnitude and modalities of recovery are very different in the different sub-movements. These results suggest that in order to maximize the recovery the modulation of assistance should occur at the level of each sub-movement.
Effect of Gravity on Robot-Assisted Motor Training After Chronic Stroke: A Randomized Trial
Archives of Physical Medicine and Rehabilitation, 2011
Objectives: To determine the efficacy of 2 distinct 6-week robot-assisted reaching programs compared with an intensive conventional arm exercise program (ICAE) for chronic, strokerelated upper-extremity (UE) impairment. To examine whether the addition of robot-assisted training out of the horizontal plane leads to improved outcomes. Design: Randomized controlled trial, single-blinded, with 12-week follow-up. Setting: Research setting in a large medical center. Participants: Adults (Nϭ62) with chronic, stroke-related arm weakness stratified by impairment severity using baseline UE motor assessments. Interventions: Sixty minutes, 3 times a week for 6 weeks of robot-assisted planar reaching (gravity compensated), combined planar with vertical robot-assisted reaching, or intensive conventional arm exercise program. Main Outcome Measure: UE Fugl-Meyer Assessment (FMA) mean change from baseline to final training. Results: All groups showed modest gains in the FMA from baseline to final with no significant between group differences. Most change occurred in the planar robot group (mean change Ϯ SD, 2.94Ϯ0.77; 95% confidence interval [CI], 1.40-4.47). Participants with greater motor impairment (nϭ41) demonstrated a larger difference in response (mean change Ϯ SD, 2.29Ϯ0.72; 95% CI, 0.85-3.72) for planar robot-assisted exercise compared with the intensive conventional arm exercise program (mean change Ϯ SD, 0.43Ϯ0.72; 95% CI,-1.00 to 1.86). Conclusions: Chronic UE deficits because of stroke are responsive to intensive motor task training. However, training outside the horizontal plane in a gravity present environment using a combination of vertical with planar robots was not superior to training with the planar robot alone.
Effects of robotic therapy on motor impairment and recovery in chronic stroke
Archives of Physical Medicine and Rehabilitation, 2003
Objective: To examine whether robotic therapy can reduce motor impairment and enhance recovery of the hemiparetic arm in persons with chronic stroke. Design: Pre-posttest design. Setting: Rehabilitation hospital, outpatient care. Participants: Volunteer sample of 20 persons diagnosed with a single, unilateral stroke within the past 1 to 5 years, with persistent hemiparesis. Interventions: Robotic therapy was provided 3 times weekly for 6 weeks. Subjects able to reach robot targets were randomly assigned to sensorimotor or progressive-resistive robotic therapy groups. Robotic therapy consisted of goal-directed, planar reaching tasks to exercise the hemiparetic shoulder and elbow. Main Outcome Measures: The Modified Ashworth Scale, Fugl-Meyer test of upper-extremity function, Motor Status Scale (MSS) score, and Medical Research Council motor power score. Results: Evaluations by a single blinded therapist revealed statistically significant gains from admission to discharge (PϽ.05) on the Fugl-Meyer test, MSS score, and motor power score. Secondary analyses revealed group differences: the progressive-resistive therapy group experienced nonspecific improvements on wrist and hand MSS scores that were not observed in the sensorimotor group. Conclusions: Robotic therapy may complement other treatment approaches by reducing motor impairment in persons with moderate to severe chronic impairments.
Robot therapy for stroke survivors: proprioceptive training and regulation of assistance
Studies in health technology and informatics, 2009
Robot therapy seems promising with stroke survivors, but it is unclear which exercises are most effective, and whether other pathologies may benefit from this technique. In general, exercises should exploit the adaptive nature of the nervous system, even in chronic patients. Ideally, exercise should involve multiple sensory modalities and, to promote active subject participation, the level of assistance should be kept to a minimum. Moreover, exercises should be tailored to the different degrees of impairment, and should adapt to changing performance. To this end, we designed three tasks: (i) a hitting task, aimed at improving the ability to perform extension movements; (ii) a tracking task, aimed at improving visuo-motor control; and (iii) a bimanual task, aimed at fostering inter-limb coordination. All exercises are conducted on a planar manipulandum with two degrees of freedom, and involve alternating blocks of exercises performed with and without vision. The degree of assistance ...
Psychophysiological responses to robot training in different recovery phases after stroke
age (years)
Psychophysiological responses have become a valuable tool in human-robot interaction since they provide an objective estimate of the user's psychological state. Unfortunately, their usefulness in rehabilitation robotics is uncertain since they are influenced by both physical activity and pathological conditions such as stroke. We performed psychophysiological measurements in subacute and chronic stroke patients as well as healthy controls during a reaching and grasping exercise task performed in a multimodal virtual environment. Furthermore, we evaluated the differences in kinematic and static parameters between the three groups of subjects. The results of the observed kinematic and static evaluation parameters showed significant differences when different assistive modes enabled the subject to focus on a particular function of the exercise, like reaching or grasping, or coordinated actions that combine reaching and grasping, reflecting the motor abilities of the individual. The analysis of psychophysiological responses suggests that both chronic and subacute stroke subjects have weaker psychophysiological responses than healthy subjects, though the responses of chronic patients have recovered somewhat. This certainly indicates that further studies are needed before psychophysiological responses can be used in clinical practice.
Robot training for hand motor recovery in subacute stroke patients: A randomized controlled trial
Journal of Hand Therapy, 2016
Background. Evidence of superiority of robot training for the hand over classical therapies remains controversial. During subacute stage, hand training is likely to be the most useful. Aim. To establish whether robot active assisted therapies provides any additional motor recovery for the hand when administered during the subacute stage (<4 months from event) in a Mexican adult population diagnosed with stroke. Hypothesis. Compared to classical occupational therapy, robot based therapies for hand recovery will show significant differences at subacute stages. Trial Design. Pre-post parallel-group. Methods. A between subjects randomized controlled experiment was carried out on subacute stroke patients (n=17) comparing robot active assisted therapy (RT) with a classical occupational therapy (OT). Both groups received 40 sessions ensuring at least 300 repetitions per session. Treatment duration was (mean±std) 2.18±1.25 months for the control group and 2.44±0.88 months for the study group. Primary outcome was motor dexterity changes assessed with Fugl-Meyer (FMA) and Motricity Index (MI). Results. Both groups (OT: n=8; RT: n=9) exhibited significant improvements for the hand with respect to their baseline values at therapy onset (Non-parametric Cliff's delta-within effect sizes: dw OT-FMA =0.5, dw OT-MI =0.5, dw RT-FMA =1, dw RT-MI =1). Regarding differences between the therapies; Fugl-Meyer indicated a significant advantage for the hand training with the robot, whilst the Motricity index suggested a greater improvement (size effect) in