Gerard G. Fluet

Sensorimotor training in virtual reality: A review

Recent experimental evidence suggests that rapid advancement of virtual reality (VR) technologies has great potential for the development of novel strategies for sensorimotor training in neurorehabilitation. We discuss what the adaptive and engaging virtual environments can provide for massive and intensive sensorimotor stimulation needed to induce brain reorganization.Second, discrepancies between the veridical and virtual feedback can be introduced in VR to facilitate activation of targeted brain networks, which in turn can potentially speed up the recovery process. Here we review the existing experimental evidence regarding the beneficial effects of training in virtual environments on the recovery of function in the areas of gait,upper extremity function and balance, in various patient populations. We also discuss possible mechanisms underlying these effects. We feel that future research in the area of virtual rehabilitation should follow several important paths. Imaging studies to evaluate the effects of sensory manipulation on brain activation patterns and the effect of various training parameters on long term changes in brain function are needed to guide future clinical inquiry. Larger clinical studies are also needed to establish the efficacy of sensorimotor rehabilitation using VR in various clinical populations and most importantly, to identify VR training parameters that are associated with optimal transfer to real-world functional improvements.

Design of a complex virtual reality simulation to train finger motion for persons with hemiparesis: a proof of concept study.

BackgroundCurrent neuroscience has identified rehabilitation approaches with the potential to stimulate adaptive changes in the brains of persons with hemiparesis. These approaches include, intensive task-oriented training, bimanual activities and balancing proximal and distal upper extremity interventions to reduce competition between these segments for neural territory.MethodsThis paper describes the design and feasibility testing of a robotic/virtual environment system designed to train the hand and arm of persons with hemiparesis. The system employs a simulated piano that presents visual, auditory and tactile feedback comparable to an actual piano. Arm tracking allows patients to train both the arm and hand as a coordinated unit, emphasizing the integration of both transport and manipulation phases. The piano trainer includes songs and scales that can be performed with one or both hands. Adaptable haptic assistance is available for more involved subjects. An algorithm adjusts task difficulty in proportion to subject performance. A proof of concept study was performed on four subjects with upper extremity hemiparesis secondary to chronic stroke to establish: a) the safety and feasibility of this system and b) the concurrent validity of robotically measured kinematic and performance measures to behavioral measures of upper extremity function.ResultsNone of the subjects experienced adverse events or responses during or after training. As a group, the subjects improved in both performance time and key press accuracy. Three of the four subjects demonstrated improvements in fractionation, the ability to move each finger individually. Two subjects improved their aggregate time on the Jebsen Test of Hand Function and three of the four subjects improved in Wolf Motor Function Test aggregate time.ConclusionThe system designed in this paper has proven to be safe and feasible for the training of hand function for persons with hemiparesis. It features a flexible design that allows for the use and further study of adjustments in point of view, bilateral and unimanual treatment modes, adaptive training algorithms and haptically rendered collisions in the context of rehabilitation of the hemiparetic hand.

Incorporating Haptic Effects Into Three-Dimensional Virtual Environments to Train the Hemiparetic Upper Extremity

Current neuroscience has identified several constructs to increase the effectiveness of upper extremity rehabilitation. One is the use of progressive, skill acquisition-oriented training. Another approach emphasizes the use of bilateral activities. Building on these principles, this paper describes the design and feasibility testing of a robotic/virtual environment system designed to train the arm of persons who have had strokes. The system provides a variety of assistance modes, scalable workspaces and hand-robot interfaces allowing persons with strokes to train multiple joints in three dimensions. The simulations utilize assistance algorithms that adjust task difficulty both online and offline in relation to subject performance. Several distinctive haptic effects have been incorporated into the simulations. An adaptive master-slave relationship between the unimpaired and impaired arm encourages active movement of the subjects hemiparetic arm during a bimanual task. Adaptive anti-gravity support and damping stabilize the arm during virtual reaching and placement tasks. An adaptive virtual spring provides assistance to complete the movement if the subject is unable to complete the task in time. Finally, haptically rendered virtual objects help to shape the movement trajectory during a virtual placement task. A proof of concept study demonstrated this system to be safe, feasible and worthy of further study.

The New Jersey Institute of Technology Robot-Assisted Virtual Rehabilitation (NJIT-RAVR) system for children with cerebral palsy: a feasibility study

BackgroundWe hypothesize that the integration of virtual reality (VR) with robot assisted rehabilitation could be successful if applied to children with hemiparetic CP. The combined benefits of increased attention provided by VR and the larger training stimulus afforded by adaptive robotics may increase the beneficial effects of these two approaches synergistically. This paper will describe the NJIT-RAVR system, which combines adaptive robotics with complex VR simulations for the rehabilitation of upper extremity impairments and function in children with CP and examine the feasibility of this system in the context of a two subject training study.MethodsThe NJIT-RAVR system consists of the Haptic Master, a 6 degrees of freedom, admittance controlled robot and a suite of rehabilitation simulations that provide adaptive algorithms for the Haptic Master, allowing the user to interact with rich virtual environments. Two children, a ten year old boy and a seven year old girl, both with spastic hemiplegia secondary to Cerebral Palsy were recruited from the outpatient center of a comprehensive pediatric rehabilitation facility. Subjects performed a battery of clinical testing and kinematic measurements of reaching collected by the NJIT-RAVR system. Subjects trained with the NJIT-RAVR System for one hour, 3 days a week for three weeks. The subjects played a combination of four or five simulations depending on their therapeutic goals, tolerances and preferences. Games were modified to increase difficulty in order to challenge the subjects as their performance improved. The testing battery was repeated following the training period.ResultsBoth participants completed 9 hours of training in 3 weeks. No untoward events occurred and no adverse responses to treatment or complaints of cyber sickness were reported. One participant showed improvements in overall performance on the functional aspects of the testing battery. The second subject made improvements in upper extremity active range of motion and in kinematic measures of reaching movements.ConclusionWe feel that this study establishes the feasibility of integrating robotics and rich virtual environments to address functional limitations and decreased motor performance in children with mild to moderate cerebral palsy.

Robotically facilitated virtual rehabilitation of arm transport integrated with finger movement in persons with hemiparesis

BackgroundRecovery of upper extremity function is particularly recalcitrant to successful rehabilitation. Robotic-assisted arm training devices integrated with virtual targets or complex virtual reality gaming simulations are being developed to deal with this problem. Neural control mechanisms indicate that reaching and hand-object manipulation are interdependent, suggesting that training on tasks requiring coordinated effort of both the upper arm and hand may be a more effective method for improving recovery of real world function. However, most robotic therapies have focused on training the proximal, rather than distal effectors of the upper extremity. This paper describes the effects of robotically-assisted, integrated upper extremity training.MethodsTwelve subjects post-stroke were trained for eight days on four upper extremity gaming simulations using adaptive robots during 2-3 hour sessions.ResultsThe subjects demonstrated improved proximal stability, smoothness and efficiency of the movement path. This was in concert with improvement in the distal kinematic measures of finger individuation and improved speed. Importantly, these changes were accompanied by a robust 16-second decrease in overall time in the Wolf Motor Function Test and a 24-second decrease in the Jebsen Test of Hand Function.ConclusionsComplex gaming simulations interfaced with adaptive robots requiring integrated control of shoulder, elbow, forearm, wrist and finger movements appear to have a substantial effect on improving hemiparetic hand function. We believe that the magnitude of the changes and the stability of the patients function prior to training, along with maintenance of several aspects of the gains demonstrated at retention make a compelling argument for this approach to training.

Interfacing a haptic robotic system with complex virtual environments to treat impaired upper extremity motor function in children with cerebral palsy

Objective: To investigate the ability of the New Jersey Institute of Technology Robot Assisted Virtual Rehabilitation (NJIT-RAVR) system training to elicit changes in upper extremity (UE) function in children with hemiplegia secondary to cerebral palsy. Methods: Nine children (mean age 9 years, three males) participated in three pilots. Subjects trained 1 hour, 3 days a week for 3 weeks. Two groups performed this protocol as their only intervention. The third group also performed 5–6 hours of constraint-induced movement therapy. Results: All subjects participated in a short programme of nine, 60-minute training sessions without adverse effects. As a group, subjects demonstrated statistically significant improvements in Melbourne Assessment of Unilateral Upper Limb Function Test, a composite of three timed UE tasks and several measurements of reaching kinematics. Several subjects demonstrated clinically significant improvements in active shoulder abduction and flexion as well as forearm supination. Conclusion: Three small pilots of NJIT-RAVR training demonstrated measurable benefit with no complications, warranting further examination.

Recovery of hand function in virtual reality: Training hemiparetic hand and arm together or separately

This study describes a novel robotic system using haptic effects and objects, in rich, three- dimensional virtual environments (VEs) for the sensorimotor training of the hemiparetic hand. This system is used to compare effectiveness of two training paradigms, one using activities that train the hand and arm together (HAT) as a functional unit to training the hand and arm in similar conditions, separately (HAS). Four subjects practiced three hours/day for 8 days using (HAS) robotic simulations. Four subjects practiced same amount of time using HAT simulations. HAT group improved 23% in the Wolf Motor Function Test and 29% in the Jebsen Test of Hand Function, whereas HAS group only improved 14% and 8%. HAT group also demonstrated larger decreases in hand trajectory length in the VE-based training that involved reaching and object placing, indicating improved limb segment coordination, (40% HAT; 19% HAS). Both groups improved the smoothness of robotically measured hand trajectories 56%, suggesting improved motor control. During virtual piano training, subjects showed similar improvements in key press accuracy (17% HAT; 20% HAS) however, the HAT group demonstrated larger improvements in average time needed to press a key (151% HAT; 60% HAS). Our initial findings suggest that training the arm and hand as a unit following stroke may be more effective for improving upper extremity function than training the hand and arm in isolation.

Robots integrated with virtual reality simulations for customized motor training in a person with upper extremity hemiparesis: a case study.

BACKGROUND AND PURPOSE A majority of studies examining repetitive task practice facilitated by robots for the treatment of upper extremity paresis utilize standardized protocols applied to large groups. Others utilize interventions tailored to patients but do not describe the clinical decision-making process utilized to develop and modify interventions. This case study describes a robot-based intervention customized to match the goals and clinical presentation of person with upper extremity hemiparesis secondary to stroke. METHODS The patient, P.M., was an 85-year-old man with left hemiparesis secondary to an intracerebral hemorrhage 5 years prior to examination. Outcomes were measured before and after a 1-month period of home therapy and after a 1-month robotic intervention. The intervention was designed to address specific impairments identified during his physical therapy examination. When necessary, activities were modified on the basis of response to the first week of treatment. OUTCOMES P.M. trained in 12 sessions, using six virtually simulated activities. Modifications to original configurations of these activities resulted in performance improvements in five of these activities. P.M. demonstrated a 35-second improvement in Jebsen Test of Hand Function time and a 44-second improvement in Wolf Motor Function Test time subsequent to the robotic training intervention. Reaching kinematics, 24-hour activity measurement, and scores on the Hand and Activities of Daily Living scales of the Stroke Impact Scale all improved as well. DISCUSSION A customized program of robotically facilitated rehabilitation was associated with short-term improvements in several measurements of upper extremity function in a patient with chronic hemiparesis.

Learning in a virtual environment using haptic systems for movement re-education: can this medium be used for remodeling other behaviors and actions?

Robotic systems that are interfaced with virtual reality gaming and task simulations are increasingly being developed to provide repetitive intensive practice to promote increased compliance and facilitate better outcomes in rehabilitation post-stroke. A major development in the use of virtual environments (VEs) has been to incorporate tactile information and interaction forces into what was previously an essentially visual experience. Robots of varying complexity are being interfaced with more traditional virtual presentations to provide haptic feedback that enriches the sensory experience and adds physical task parameters. This provides forces that produce biomechanical and neuromuscular interactions with the VE that approximate real-world movement more accurately than visual-only VEs, simulating the weight and force found in upper extremity tasks. The purpose of this article is to present an overview of several systems that are commercially available for ambulation training and for training movement of the upper extremity. We will also report on the system that we have developed (NJIT-RAVR system) that incorporates motivating and challenging haptic feedback effects into VE simulations to facilitate motor recovery of the upper extremity post-stroke. The NJIT-RAVR system trains both the upper arm and the hand. The robotic arm acts as an interface between the participants and the VEs, enabling multiplanar movements against gravity in a three-dimensional workspace. The ultimate question is whether this medium can provide a motivating, challenging, gaming experience with dramatically decreased physical difficulty levels, which would allow for participation by an obese person and facilitate greater adherence to exercise regimes.

Coordination changes demonstrated by subjects with hemiparesis performing hand-arm training using the NJIT-RAVR robotically assisted virtual rehabilitation system

Various authors have described pre and post testing improvements in upper limb coordination as a result of intensive upper limb interventions. While the ability to alter coordination patterns as a result of repetitive hand-arm movement is established, patterns of change in the relationship between proximal and distal effectors of the UE over the course of multiple sessions of training have not been described in the rehabilitation literature. In this study eight subjects (5 male, 3 female) with a mean age of 56.4 years (SD=14.2) and a mean time since CVA of 54.7 months post-stroke (SD=51.7) were trained for eight, 2–3 hour sessions on four robotically facilitated virtual rehabilitation activities. This paper will present 1) Functional performance and pre and post testing kinematic analysis for the eight subjects 2) More extensive analysis of the change in hand and arm coordination over the course of the eight session intervention demonstrated by one of the subjects from this sample 3) Kinematic analysis of another subject from this sample performing an un-trained reaching and grasping activity, before and after training.