Application of Virtual Reality in Neuro-Rehabilitation: An Overview <s> 431 <s> Knowledge of results (KR)-information feed- back about goal achievement-has been one of the most exten- sively examined variables in motor learning. In most natural movement learning situations, however, instructors more com- monly provide augmented information regarding various kine- matic or kinetic aspects of the movement pattern itself (sometimes termed knowledge of performance, KP). But despite the inherent interest in kinematic feedback, several factors reviewed here have operated to inhibit its study, the most important of which has been the lack of a suitable laboratory task and paradigm. The limita- tions of earlier paradigms have concerned (a) the use of overly simple motor behaviors, probably to minimize the problems in kinematic measurement, (b) the tendency for the environmental goal of the task to be isomorphic with the kinematic pattern, and (c) the failure to use transfer or retention tests as measures of learning effects of the feedback manipulations. In this article, we describe our efforts to create a new paradigm for kinematic feed- back, the rationale for its development, and the details of its op- eration. Finally, we provide evidence that the task and paradigm are sensitive to manipulations of kinematic feedback, providing some assurance that the paradigm can potentially answer future research questions about the role of kinematic feedback for learning. n this article, we present a new research task and para- I digm-developed over the past several years at our labo- ratory at UCLA-that seems suitable for the laboratory study of feedback of the type usually provided by instruc- tors, coaches, therapists, and teachers in real-world move- ment learning settings. Despite a strong, decades-long in- terest in such issues for both practical and theoretical reasons, we argue that the understanding of such feedback processes for learning is underdeveloped, at least in part because a suitable paradigm for its study has not been avail- able. In the sections that follow, we describe several factors that have inhibited the development of such a paradigm in the past, we discuss the important requirements that led to our new pmdigm, and we describe effectiveness of the par- adigm for feedback research. <s> BIB001 </s> Application of Virtual Reality in Neuro-Rehabilitation: An Overview <s> 431 <s> Observations of behavior and neural activity in premotor cortex of monkeys learning to pair an arbitrary visual stimulus with one of a set of previously learned behaviors are modeled with a network comprising a large number of motor selection columns. Reinforcement learning is used to recognize new visual patterns and acquire the appropriate visual-motor conditions. The architecture employs a distributed representation in which a single pattern is coded by a small subset of columns. A column is initially able to respond to many different inputs; as it learns to trigger a motor program, its responses become more narrowly defined. Each column's output is a set of votes for the various motor programs. The votes for each program are collected by selection units, which drive a winner-take-all circuit to determine whether a particular motor program is executed. The model is successful in reproducing the sequence of behavioral responses given by the subjects, as well as a number of phenomena that have been obser... <s> BIB002 </s> Application of Virtual Reality in Neuro-Rehabilitation: An Overview <s> 431 <s> BACKGROUND AND PURPOSE ::: Rehabilitation therapy is believed to be useful during the first few months after stroke when recovery usually takes place. However, evidence exists that this may not be the rule for all stroke victims. Therefore, we investigated, in a selected group of poststroke patients, the profile of recovery in response to long-term rehabilitation therapy. ::: ::: ::: METHODS ::: Fifty-one hemiplegic subjects unable to walk 3 months after stroke were enrolled in this study. Patients underwent consecutive periods of rehabilitation up to 2 years after the cerebrovascular accident. Autonomy in daily living activities and the degree of neurological compromission were periodically assessed with the Barthel Index and a neurological scale designed for hemiplegic subjects. The main features of the patients were also evaluated as a possible predictor of outcome. ::: ::: ::: RESULTS ::: In a consistent percentage of the patients, significant gains in gait and daily living abilities were observed during the first year and, in individual cases, during the second year after stroke. At the end of the study, 74% of the patients regained their capacity to walk without assistance, and up to 79% had a Barthel Index score above 70. Sphincter function, level of neurological impairments, and capacity in daily living activities are significantly related to the outcome of the patients as a whole but were not useful to anticipate the outcome of each patient. ::: ::: ::: CONCLUSIONS ::: These results suggest that disabled poststroke subjects may attain significative functional improvements in response to prolonged restorative therapy. However, the possibility of predicting the outcome of individual patients appears the major problem to solve in order to assign to long-term rehabilitation programs only patients who will benefit from the therapy. <s> BIB003 </s> Application of Virtual Reality in Neuro-Rehabilitation: An Overview <s> 431 <s> Abstract Reinforcement learning refers to improving performance through trial-and-error. Despite recent progress in developing artificial learning systems, including new learning methods for artificial neural networks, most of these systems learn under the tutelage of a knowledgeable ‘teacher’ able to tell them how to respond to a set of training stimuli. Learning under these conditions is not adequate, however, when it is costly, or even impossible, to obtain this kind of training information. Reinforcement learning is attracting increasing attention in computer science and engineering because it can be used by autonomous systems to learn from their experiences instead of from knowledgeable teachers, and it is attracting attention in computational neuroscience because it is consonant with biological principles. Recent research has improved the efficiency of reinforcement learning and has provided some striking examples of its capabilities. <s> BIB004 </s> Application of Virtual Reality in Neuro-Rehabilitation: An Overview <s> 431 <s> Research into stroke rehabilitation is an active area of investigation, and ample evidence suggests that patients with moderate deficits benefit from focused rehabilitation programs. Increasing age, stroke severity, and neuropsychological deficits are associated with a poor outcome. In this review we will discuss the most recent literature on stroke rehabilitation, with special emphasis on outcome predictors, motor recovery, and therapeutic strategies for aphasia and neuropsychological deficits. <s> BIB005 </s> Application of Virtual Reality in Neuro-Rehabilitation: An Overview <s> 431 <s> Background and Purpose. Partial weight bearing (PWB) is a skill commonly taught by physical therapists. This study compared the effects of practice with either augmented feedback provided during the task (concurrent feedback) or augmented feedback provided after the task (postresponse feedback) for the learning of PWB with crutches. Subjects. Sixty young adults without known impairment of the neuromusculoskeletal system volunteered for the study. Methods. Subjects practiced supporting 30% of body weight while stepping onto a floor scale. Augmented feedback was provided during each trial for the concurrent feedback group and either following each trial or after every five trials for the postresponse feedback groups. Subjects returned 2 days later for a no-feedback retention test. Results. During practice, the concurrent feedback group was more accurate and consistent than either of the postresponse feedback groups. During retention, however, the postresponse feedback groups were the most accurate; all groups were equally consistent during retention. Conclusion and Discussion. These results suggest that practice with concurrent feedback is beneficial for the immediate performance but not for the learning of this sensorimotor skill. [Winstein CJ, Pohl PS, Cardinale C, et al. Learning a partial-weight-bearing skill: effectiveness of two forms of feedback. Phys Ther. 1996;76:985-993.1 <s> BIB006 </s> Application of Virtual Reality in Neuro-Rehabilitation: An Overview <s> 431 <s> Abstract One can use a number of techniques (e.g., from videotaping to computer enhancement of the environment) to augment the feedback that a subject usually receives during training on a motor task. Although some forms of augmented feedback have been shown to enhance performance on isolated isometric tasks during training, when the feedback has been removed subjects have sometimes not been able to perform as well in the “real-world” task as controls. Indeed, for realistic, nonisometric motor tasks, improved skill acquisition because of augmented feedback has not been demonstrated. In the present experiments, subjects (Experiment 1, N = 42; Experiment 2, N = 21) performed with a system that was designed for teaching a difficult multijoint movement in a table tennis environment. The system was a fairly realistic computer animation of the environment and included paddles for the teacher and subject, as well as a virtual ball. Each subject attempted to learn a difficult shot by matching the pattern of movem... <s> BIB007 </s> Application of Virtual Reality in Neuro-Rehabilitation: An Overview <s> 431 <s> Enhanced feedback provided by a virtual reality system has been shown to promote motor learning in normal subjects. We evaluated whether this approach could be useful for treating patients with motor deficits following brain lesions. Thirty subjects with mild to intermediate arm impairments due to stroke were selected for the study. They were randomly divided into two groups: the patients assigned to the study group received an hour of reinforced feedback in virtual-environment (RFVE) therapy daily for one month. The patients assigned to the control group received the same amount of treatment in time, consisting of traditional physical therapy (Conventional Therapy, CT). In both groups, before and after the therapy, we assessed the degree of motor impairment and autonomy in daily living activities using the Fugl-Meyer scale for the upper extremities and Functional Independence Measure, respectively. Both therapies yielded significant improvements over baseline values in the mean scores on the Fugl-Meyer Upper Extremity and Functional Independence Measure scales. These data indicate that motor recovery in post-stroke patients may be promoted by the enhanced feedback provided in a virtual environment. <s> BIB008
PC workstation with a wall screen), a motion tracking device and the dedicated software for editing 3D-scenarios in a learning-by-imitation rehabilitation process with a virtual teacher. Therapists set the virtual scenarios characteristics and the motor training complexity to match each patient's motor impairment and rehabilitation protocol, set the starting position, target location and orientation, designed simple/complex tasks, added or removed non-pertinent virtual objects (distractive elements) to increase/reduce the task level of difficulty, recorded trajectory of the desired movement to be (re)learned by the subject, with the virtual teacher visible or hidden as advisable. The degree of motor impairment or recovery and the attained levels of autonomy in daily living activities were measured by the Fugel-Meyer (FM) UE score and the Functional Independence Measure scale (FIM) before and after the therapy, and by means of kinematic measures such as the movement morphology and mean duration and speed. Improvement was observed in the FM UE and FIM mean scores (with 15% and 6% increases, respectively) and in the movement mean duration (18%) and speed (23%), with better regularity of trajectories. Improvements do not appear to have been influenced by age, time since stroke or site of brain damage, as already noted in previous studies BIB005   Tangeman et al, 1990; BIB003 . Instead, the severity of impairment was crucial for the outcome and a severe initial impairment was more difficult to rehabilitate. Comparison between the degrees of recovery attained after standard or VR-reinforced learning in two randomly assigned post-stroke patient groups BIB008 showed significantly increased FM UE scores in all 30 patients, but improvement was greater after VR-supported therapy. The different outcome was ascribed, at least in part, to the feedback information about knowledge-of-results and knowledge-of-performance provided by the system BIB007 BIB001 BIB006 and to the reinforced learning provided by the VR-based rehabilitation approach BIB004  BIB002  .