Error Augmented Robotic Rehabilitation of the Upper Limb - A Review <s> Success of Error Augmented Haptic Feedback Trials <s> Based on recent studies of neuro-adaptive control, we tested a new iterative algorithm to generate custom training forces to "trick" subjects into altering their target-directed reaching movements to a prechosen movement as an after-effect of adaptation. The prechosen movement goal, a sinusoidal-shaped path from start to end point, was never explicitly conveyed to the subject. We hypothesized that the adaptation would cause an alteration in the feedforward command that would result in the prechosen movement. Our results showed that when forces were suddenly removed after a training period of 330 movements, trajectories were significantly shifted toward the prechosen movement. However, de-adaptation occurred (i.e., the after-effect "washed out") in the 50-75 movements that followed the removal of the training forces. A second experiment suppressed vision of hand location and found a detectable reduction in the washout of after-effects, suggesting that visual feedback of error critically influences learning. A final experiment demonstrated that after-effects were also present in the neighborhood of training-44% of original directional shift was seen in adjacent, unpracticed movement directions to targets that were 60/spl deg/ different from the targets used for training. These results demonstrate the potential for these methods for teaching motor skills and for neuro-rehabilitation of brain-injured patients. This is a form of "implicit learning," because unlike explicit training methods, subjects learn movements with minimal instructions, no knowledge of, and little attention to the trajectory. <s> BIB001 </s> Error Augmented Robotic Rehabilitation of the Upper Limb - A Review <s> Success of Error Augmented Haptic Feedback Trials <s> The present study is aimed at developing new rehabilitation protocols to be used in post-stroke robotic-aided therapy. In the recent past, it has been suggested that the use of robotic training forces that enhance error instead of reducing it, could stimulate new learning and feedback strategies at the base of an effective motor recovery. Starting from these findings, in this work two different robotic-aided therapies were compared: the first was based on the constraint induced movement therapy, the second employed an unstable training force field increasing path errors performed by the subjects. The results shows that the use of the unstable divergent force field can increase the recovery, especially in people with mild level of impairment. <s> BIB002 </s> Error Augmented Robotic Rehabilitation of the Upper Limb - A Review <s> Success of Error Augmented Haptic Feedback Trials <s> Recent research has suggested that enhanced retraining for stroke patients using haptics (robotic forces) and graphics (visual display) to generate a practice environment that can artificially enhance error rather than reducing it, can stimulate new learning and foster accelerated recovery. We present an evaluation of early results of this novel post-stroke robotic-aided therapy trial that incorporates these ideas in a large VR system and simultaneously employs the patient, the therapist, and the technology to accomplish effective therapy. <s> BIB003 </s> Error Augmented Robotic Rehabilitation of the Upper Limb - A Review <s> Success of Error Augmented Haptic Feedback Trials <s> BackgroundCerebellar symptoms are extremely disabling and are common in Multiple Sclerosis (MS) subjects. In this feasibility study, we developed and tested a robot therapy protocol, aimed at the rehabilitation of incoordination in MS subjects.MethodsEight subjects with clinically defined MS performed planar reaching movements while grasping the handle of a robotic manipulandum, which generated forces that either reduced (error-reducing, ER) or enhanced (error-enhancing, EE) the curvature of their movements, assessed at the beginning of each session. The protocol was designed to adapt to the individual subjects' impairments, as well as to improvements between sessions (if any). Each subject went through a total of eight training sessions. To compare the effect of the two variants of the training protocol (ER and EE), we used a cross-over design consisting of two blocks of sessions (four ER and four EE; 2 sessions/week), separated by a 2-weeks rest period. The order of application of ER and EE exercises was randomized across subjects. The primary outcome measure was the modification of the Nine Hole Peg Test (NHPT) score. Other clinical scales and movement kinematics were taken as secondary outcomes.ResultsMost subjects revealed a preserved ability to adapt to the robot-generated forces. No significant differences were observed in EE and ER training. However over sessions, subjects exhibited an average 24% decrease in their NHPT score. The other clinical scales showed small improvements for at least some of the subjects. After training, movements became smoother, and their curvature decreased significantly over sessions.ConclusionsThe results point to an improved coordination over sessions and suggest a potential benefit of a short-term, customized, and adaptive robot therapy for MS subjects. <s> BIB004 </s> Error Augmented Robotic Rehabilitation of the Upper Limb - A Review <s> Success of Error Augmented Haptic Feedback Trials <s> Here we present results where nineteen stroke survivors with chronic hemiparesis simultaneously employed the trio of patient, therapist, and machine. Massed practice combined with error augmentation, where haptic (robotic forces) and graphic (visual display) distortions are used to enhance the feedback of error, was compared to massed practice alone. The 6-week randomized crossover design involved approximately 60 minutes of daily treatment three times per week for two weeks, followed by one week of rest, and then repeated using the alternate treatment protocol. A therapist provided a visual target using a tracking device that moved a cursor in front of the patient, who was instructed to maintain the cursor on the target. The patient, therapist, technician-operator, and rater were blinded to treatment type. Several clinical measures gauged outcomes at the beginning and end of each 2-week period and one week post training. Results showed incremental benefit across most but not all days, abrupt gains in performance, and a benefit to error augmentation training in final evaluations. This application of interactive technology may be a compelling new method for enhancing a therapist's productivity in stroke-rehabilitation. <s> BIB005 </s> Error Augmented Robotic Rehabilitation of the Upper Limb - A Review <s> Success of Error Augmented Haptic Feedback Trials <s> Feedback is an important element in motor learning during rehabilitation therapy following stroke. The objective of this pilot study was to better understand the effect of position feedback during task-oriented reach training of the upper limb in people with chronic stroke. Five subjects participated in the training for 30 minutes three times a week for 6 weeks. During training, subjects performed reaching movements over a predefined path. When deviation from this path occurred, shoulder and elbow joints received position feedback using restraining forces. We recorded the amount of position feedback used by each subject. During pre- and posttraining assessments, we collected data from clinical scales, isometric strength, and workspace of the arm. All subjects showed improvement on one or several kinematic variables during a circular motion task after training. One subject showed improvement on all clinical scales. Subjects required position feedback between 7.4% and 14.7% of training time. Although augmented feedback use was limited, kinematic outcome measures and movement performance during training increased in all subjects, which was comparable with other studies. Emphasis on movement errors at the moment they occur may possibly stimulate motor learning when movement tasks with sufficiently high levels of difficulty are applied. <s> BIB006 </s> Error Augmented Robotic Rehabilitation of the Upper Limb - A Review <s> Success of Error Augmented Haptic Feedback Trials <s> Background ::: Robot-generated deviating forces during multijoint reaching movements have been applied to investigate motor control and to tune neuromotor adaptation. Can the application of force to limbs improve motor learning? In this framework, the response to altered dynamic environments of children affected by primary dystonia has never been studied. <s> BIB007 </s> Error Augmented Robotic Rehabilitation of the Upper Limb - A Review <s> Success of Error Augmented Haptic Feedback Trials <s> To study the effects of different feedback error amplification methods on a subject's upper-limb motor learning and affect during a point-to-point reaching exercise, we developed a real-time controller for a robotic manipulandum. The reaching environment was visually distorted by implementing a thirty degrees rotation between the coordinate systems of the robot's end-effector and the visual display. Feedback error amplification was provided to subjects as they trained to learn reaching within the visually rotated environment. Error amplification was provided either visually or through both haptic and visual means, each method with two different amplification gains. Subjects' performance (i.e., trajectory error) and self-reports to a questionnaire were used to study the speed and amount of adaptation promoted by each error amplification method and subjects' emotional changes. We found that providing haptic and visual feedback promotes faster adaptation to the distortion and increases subjects' satisfaction with the task, leading to a higher level of attentiveness during the exercise. This finding can be used to design a novel exercise regimen, where alternating between error amplification methods is used to both increase a subject's motor learning and maintain a minimum level of motivational engagement in the exercise. In future experiments, we will test whether such exercise methods will lead to a faster learning time and greater motivation to pursue a therapy exercise regimen. <s> BIB008
By studying the results of the trials that utilized haptic error augmentation one can conclude that the different conditions are affected differently by this modality. Stroke patients seem to be more positively affected by haptic error augmentation exercises as all studies that performed such experiments on stroke patients conclude that the group that received error augmented therapy showed improvement in the function of the paretic limb. However, such a statement cannot be definitively made as from the reviewed studies, the ones that performed trials on participants suffering from primary dystonia and multiple sclerosis were significantly less than the trials on stroke patients. Therefore, the reviewed studies cannot be compared directly in terms of the outcome for individuals with different conditions. More specifically, studies BIB002 BIB005 BIB006 conclusively report that the patients who received error augmented therapy were positively affected. In study BIB003 ) the authors report that while the kinematic measures indicate improvement, clinical measures did not provide any measurable change in the performance and they suggest that results were probably hindered by the small trial group and the small number of sessions. The difference in the outcome of kinematic and the clinical measures may be due to the fact that kinematic measures in most cases provide better responsiveness, that is they are more capable of accurately detecting changes over time, than clinical scales  , hence are more sensitive detectors of change. Both studies that employed participants with multiple sclerosis report positive outcomes. Study (Squeri et al., 2007a) concluded that at the end of the sessions the participants exhibited faster, smoother and more symmetric movement. On the other hand, study BIB004 presents similar results but did not indicate significant differences on the outcome between error reducing and error augmenting therapy, with the only exception being a reduction in a tremor related clinical measure which occurred only after error augmented therapy. As such, the improvement presented in both studies may be due to the fact that the participants experienced the positive effects of adaptation in a dynamic environment regardless of the conditions applied within that environment. With regards to children suffering from primary dystonia BIB007 results indicate improvement in terms of optimal path control which as the authors suggest may be due to a refinement in the existing sensorimotor patterns of the impaired participants rather than due to motor learning. In the trials involving participation of able bodied individuals BIB001 BIB008 , the participants could adapt their movement to the altered environment. However, in BIB001 there was no clear difference of the effects of error augmenting therapy when compared to those from error reducing therapy. Finally, subjects in BIB008 showed improved in satisfaction, attentiveness and dominance when they were introduced to augmented error conditions despite of the type of feedback where error was augmented, but didn't show improvements on their performance. Both trials utilized a single session training scheme with relatively small number of repetitions that may have not allowed significant changes in motor adaptation to occur.