Rares Boian

Virtual reality-enhanced stroke rehabilitation

A personal computer (PC)-based desktop virtual reality (VR) system was developed for rehabilitating hand function in stroke patients. The system uses two input devices, a CyberGlove and a Rutgers Master II-ND (RMII) force feedback glove, allowing user interaction with a virtual environment. This consists of four rehabilitation routines, each designed to exercise one specific parameter of hand movement: range, speed, fractionation or strength. The use of performance-based target levels is designed to increase patient motivation and individualize exercise difficulty to a patients current state. Pilot clinical trials have been performed using the above system combined with noncomputer tasks, such as pegboard insertion or tracing of 2D patterns. Three chronic stroke patients used this rehabilitation protocol daily for two weeks. Objective measurements showed that each patient showed improvement on most of the hand parameters over the course of the training. Subjective evaluation by the patients was also positive. This technical report focuses on this newly developed technology for VR rehabilitation.

The Rutgers Master II-new design force-feedback glove

The Rutgers Master II-ND glove is a haptic interface designed for dextrous interactions with virtual environments. The glove provides force feedback up to 16 N each to the thumb, index, middle, and ring fingertips. It uses custom pneumatic actuators arranged in a direct-drive configuration in the palm. Unlike commercial haptic gloves, the direct-drive actuators make unnecessary cables and pulleys, resulting in a more compact and lighter structure. The force-feedback structure also serves as position measuring exoskeleton, by integrating noncontact Hall-effect and infrared sensors. The glove is connected to a haptic-control interface that reads its sensors and servos its actuators. The interface has pneumatic servovalves, signal conditioning electronics, A/D/A boards, power supply and an imbedded Pentium PC. This distributed computing assures much faster control bandwidth than would otherwise be possible. Communication with the host PC is done over an RS232 line. Comparative data with the CyberGrasp commercial haptic glove is presented.

Sensorimotor Training in a Virtual Reality Environment: Does It Improve Functional Recovery Poststroke?

Objective. To investigate the effectiveness of computerized virtual reality (VR) training of the hemiparetic hand of patients poststroke using a system that provides repetitive motor reeducation and skill reacquisition. Methods. Eight subjects in the chronic phase poststroke participated in a 3-week program using their hemiparetic hand in a series of interactive computer games for 13 days of training, weekend breaks, and pretests and posttests. Each subject trained for about 2 to 2.5 h per day. Outcome measures consisted of changes in the computerized measures of thumb and finger range of motion, thumb and finger velocity, fractionation (the ability to move fingers independently), thumb and finger strength, the Jebsen Test of Hand Function, and a Kinematic reach to grasp test. Results. Subjects as a group improved in fractionation of the fingers, thumb and finger range of motion, and thumb and finger speed, retaining those gains at the 1-week retention test. Transfer of these improvements was demonstrated through changes in the Jebsen Test of Hand Function and a decrease after the therapy in the overall time from hand peak velocity to the moment when an object was lifted from the table. Conclusions. It is difficult in current service delivery models to provide the intensity of practice that appears to be needed to effect neural reorganization and functional changes poststroke. Computerized exercise systems may be a way to maximize both the patients’ and the clinicians’ time. The data in this study add support to the proposal to explore novel technologies for incorporation into current practice.

Post-Stroke Rehabilitation with the Rutgers Ankle System: A Case Study

The Rutgers Ankle is a Stewart platform-type haptic interface designed for use in rehabilitation. The system supplies six-degree-of-freedom (DOF) resistive forces on the patients foot, in response to virtual reality-based exercises. The Rutgers Ankle controller contains an embedded Pentium board, pneumatic solenoid valves, valve controllers, and associated signal conditioning electronics. The rehabilitation exercise used in our case study consists of piloting a virtual airplane through loops. The exercise difficulty can be selected based on the number and placement of loops, the airplane speed in the virtual environment, and the degree of resistance provided by the haptic interface. Exercise data is stored transparently, in real time, in an Oracle database. These data consist of ankle position, forces, and mechanical work during an exercise, and over subsequent rehabilitation sessions. The number of loops completed and the time it took to do that are also stored online. A case study is presented of a patient nine months post-stroke using this system. Results showed that, over six rehabilitation sessions, the patient improved on clinical measures of strength and endurance, which corresponded well with torque and power output increases measured by the Rutgers Ankle. There were also substantial improvements in task accuracy and coordination during the simulation and the patients walking and stair-climbing ability.

A virtual reality-based exercise system for hand rehabilitation post-stroke

This paper presents preliminary results from a virtual reality (VR)-based system for hand rehabilitation that uses a CyberGlove and a Rutgers Master II-ND haptic glove. This computerized system trains finger range of motion, finger flexion speed, independence of finger motion, and finger strength using specific VR simulation exercises. A remote Web-based monitoring station was developed to allow telerehabilitation interventions. The remote therapist observes simplified versions of the patient exercises that are updated in real time. Patient data is stored transparently in an Oracle database, which is also Web accessible through a portal GUI. Thus the remote therapist or attending physician can graph exercise outcomes and thus evaluate patient outcomes at a distance. Data from the VR simulations is complemented by clinical measurements of hand function and strength. Eight chronic post-stroke subjects participated in a pilot study of the above system. In keeping with variability in both their lesion size and site and in their initial upper extremity function, each subject showed improvement on a unique combination of movement parameters in VR training. Importantly, these improvements transferred to gains on clinical tests, as well as to significant reductions in task-completion times for the prehension of real objects. These results are indicative of the potential feasibility of this exercise system for rehabilitation in patients with hand dysfunction resulting from neurological impairment.

The Rutgers Master II-ND force feedback glove

The Rutgers Master II-ND glove is a follow up on the earlier Rutgers Master II haptic interface. The redesigned glove has all the sensing placed on palm support, avoiding routing wires to the fingertips. It uses custom pneumatic actuators arranged in a direct-drive configuration between the palm and the thumb, index middle and ring fingers. The supporting glove used in the RMII design is eliminated, thus the RMII-ND can better accommodate varying hand sizes. The glove is connected to a haptic control interface that reads its sensors and servos its actuators. The interface pneumatic pulse-width modulated servo-valves have higher bandwidth than those used in the earlier RMII, resulting in better force control. A comparison with the CyberGrasp commercial haptic glove is provided.

The Rutgers Arm, a rehabilitation system in virtual reality: a pilot study.

Stroke is one of the leading causes of death and disability worldwide. Its prevalence calls for innovative rehabilitation methods. The Rutgers Arm is a novel upper extremity rehabilitation system consisting of a low-friction table, three-dimensional (3D) tracker, custom forearm support, PC workstation, library of Java 3D virtual reality (VR) exercises, clinical database module, and a tele-rehabilitation extension. The system was tested on a chronic stroke subject, under local and tele-rehabilitation conditions, over 5 weeks of training. Results show improvements in arm motor control and shoulder range of motion, corresponding to improved Fugl-Meyer test scores. Exercise duration, level of difficulty, and patient motivation were maintained under tele-rehabilitaion. A 1-week retention trial showed that gains were maintained.

A virtual reality based exercise system for hand rehabilitation post-stroke: transfer to function

We present preliminary results from a virtual reality (VR)-based system for hand rehabilitation that uses a CyberGlove and a Rutgers Master II-ND haptic glove. This system trains finger range of motion, finger flexion speed, independence of finger motion and finger strength. Eight chronic post-stroke subjects participated. In keeping with variability in both the lesion site and in initial upper extremity function, each subject showed improvement on a unique combination of movement parameters in VR training. These improvements transferred to gains on clinical tests, as well as to significant reductions in task completion times for the prehension of real objects. These results are indicative of the potential feasibility of this exercise system for rehabilitation in patients with hand dysfunction resulting from neurological impairment.

A virtual reality-based exercise program for stroke rehabilitation

A PC based desktop Virtual Reality system was developed for rehabilitating hand function in stroke patients. The system uses two hand input devices, a CyberGlove and a RMII force feedback glove, to allow the user to interact with one of four rehabilitation exercises. Each of which is designed to exercise one specific parameter of hand movement, namely range, speed, fractionation or strength. The therapy program is semi-automated and personalized to each user through the use of performance-based target levels. These are adapted between sessions in order to induce the user to improve. Feedback is provided to each user throughout the exercise sessions. To further motivate the user to continue the exercise program, screen displays are designed as interactive games. The system is described and sample data is presented from preliminary studies performed on control subjects.

Formative evaluation and preliminary findings of a virtual reality telerehabilitation system for the lower extremity

Usability studies are an essential and iterative component of technology development and ease its transfer from the laboratory to the clinic. Although such studies are standard methodology in todays graphical user-interface applications, it is not clear that current methods apply to new technologies such as virtual reality. Thus experimentation is needed to examine what existing methods can be viably transferred to the new user-interaction situations. In this paper, 5 integrated interfaces with 3 simultaneous users are evaluated via a set of usability studies, which adapt traditional methods for assessing the ease of use of the interface design. A single expert domain user was run in an intensive study that examined the therapist manual and interfaces of the Rutgers Ankle Rehabilitation System (RARS). The interface and manual were extensively modified based on this evaluation. A second study involving 5 therapists was then conducted to evaluate the telerehabilitation component of the RARS system. In both studies, the tester and developers observations, along with the session videotapes and therapist-user questionnaires, were triangulated to identify user problems and suggest design changes expected to increase the usability of the system. Changes that resulted from the analysis with the domain expert are described and recommendations for how to conduct usability studies in such multiuser remote virtual reality situations are proposed. Results from the pilot usability telemonitoring studies are also presented. The validity of usability studies in the development and refinement of rehabilitation technology is highlighted.