In this paper, the current "state of the art" for virtual reality (VR) applications in the field of motor rehabilitation is reviewed. The paper begins with a brief overview of available equipment options. Next, a discussion of the scientific rationale for use of VR in motor rehabilitation is provided. Finally, the major portion of the paper describes the various VR systems that have been developed for use with patients, and the results of clinical studies reported to date in the literature. Areas covered include stroke rehabilitation (upper and lower extremity training, spatial and perceptual-motor training), acquired brain injury, Parkinson's disease, orthopedic rehabilitation, balance training, wheelchair mobility and functional activities of daily living training, and the newly developing field of telerehabilitation. Four major findings emerge from these studies: (1) people with disabilities appear capable of motor learning within virtual environments; (2) movements learned by people with disabilities in VR transfer to real world equivalent motor tasks in most cases, and in some cases even generalize to other untrained tasks; (3) in the few studies (n = 5) that have compared motor learning in real versus virtual environments, some advantage for VR training has been found in all cases; and (4) no occurrences of cybersickness in impaired populations have been reported to date in experiments where VR has been used to train motor abilities.

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Virtual environments for motor rehabilitation: review.

Virtual reality: applications and implications for tourism.

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 patient's 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.

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Virtual reality-enhanced stroke rehabilitation

The author presents a personal assessment of the state of the art of VR. In 1994, he surveyed the field of VR. His assessment then was that VR almost worked, but that we were not yet there. There were lots of demos and pilot systems, but except for vehicle simulators and entertainment applications, VR was not yet in production use doing real work. This year he was invited to do an up-to-date assessment of VR, with funding to visit major centers in North America and Europe. Every one of the component technologies has made big strides. Moreover, I found that there now exist some VR applications routinely operated for the results they produce.

What's real about virtual reality?

Hand movement data acquisition is used in many engineering applications ranging from the analysis of gestures to the biomedical sciences. Glove-based systems represent one of the most important efforts aimed at acquiring hand movement data. While they have been around for over three decades, they keep attracting the interest of researchers from increasingly diverse fields. This paper surveys such glove systems and their applications. It also analyzes the characteristics of the devices, provides a road map of the evolution of the technology, and discusses limitations of current technology and trends at the frontiers of research. A foremost goal of this paper is to provide readers who are new to the area with a basis for understanding glove systems technology and how it can be applied, while offering specialists an updated picture of the breadth of applications in several engineering and biomedical sciences areas.

A Survey of Glove-Based Systems and Their Applications

From the Publisher:
This in-depth review of current virtual reality technology and its applications provides a detailed analysis of the engineering, scientific and functional aspects of virtual reality systems and the fundamentals of VR modeling and programming. It also contains an exhaustive list of present and future VR applications in a number of diverse fields. Virtual Reality Technology is the first book to include a full chapter on force and tactile feedback and to discuss newer interface tools such as 3-D probes and cyberscopes. Supplemented with 23 color plates and more than 200 drawings and tables which illustrate the concepts described.

Virtual Reality Technology

Research on virtual environments VE produced significant advances in computer hardware graphics boards and i/o tools and software real-time distributed simulations. However, fundamental questions remain about how user performance is affected by such factors as graphics refresh rate, resolution, control latencies, and multimodal feedback. This article reports on two experiments performed to examine dextrous manipulation of virtual objects. The first experiment studies the effect of graphics frame rate and viewing mode monoscopic vs. stereoscopic on the time required to grasp a moving target. The second experiment studies the effect of direct force feedback, pseudoforce feedback, and redundant force feedback on grasping force regulation. The trials were performed using a partially-immersive environment graphics workstation and LCD glasses, a DataGlove, and the Rutgers Master with force feedback. Results of the first experiment indicate that stereoscopic viewing is beneficial for low refresh rates it reduced task completion time by about 50% vs. monoscopic graphics. Results of the second experiment indicate that haptic feedback increases performance and reduces error rates, as compared to the open loop case with no force feedback. The best performance was obtained when both direct haptic and redundant auditory feedback were provided to the user. The large number of subjects participating in these experiments over 160 male and female indicates good statistical significance for the above results.

Effect of frame rate and force feedback on virtual object manipulation

Virtual reality (VR) involves multimodal interactions with computer‐simulated worlds through visual, auditory, and haptic feedback. This article reviews the state of the art in special‐purpose input‐output devices, such as trackers, sensing gloves, 3‐D audio cards, stereo displays, and haptic feedback masters. The integration of these devices in local and network‐distributed VR simulation systems is subsequently discussed. Finally, we present human‐factor studies that quantify the benefits of several feedback modalities on simulation realism and sensorial immersion. Specifically, we consider tracking and dextrous manipulation task performance in terms of error rates and learning times when graphics, audio, and haptic feedback are provided.

Multimodal virtual reality: input-output devices, system integration, and human factors

This paper deals with one of the key problems when interacting with virtual environments (VE): finger force feedback during manipulation of virtual objects. In the real world, control of haptic interactions with objects is achieved using the kinesthetic/tactile information. In a VE, the presentation of such information requires a dextrous hand master that provides force feedback to different fingers. The presence of friction and/or time delays and the lack of tactile information in such devices reduce operator performance. In those cases, other sensory channels such as vision and audition could be used to replace (sensory substitution) or to supplement (information redundancy) the haptic channel. In this paper, we present the result of an experimental study aimed at investigating human performance during interactions with virtual objects through different sensory channels. This study was performed using the Rutgers VR distributed system. This system enable the users to receive force informations through the haptic, visual, or auditive channel. The experiment was performed using both partially immersive monoscopic and stereoscopic visual displays. Results indicate that redundant presentation of haptic information greatly increases performance and reduce error rates as compared to the open-loop case (with no force feedback). The best results were obtained where both direct haptic and redundant sound feedback were provided. Increment of task completion time when using visual force feedback suggest an overload of the visual channel.

Human perceptual issues in virtual environments: sensory substitution and information redundancy

On October 10th 1996 and for the first time in teleoperation history, four robots of different kinematics and situated in different locations (respectively Poitiers, Grenoble and Nantes in France and Tsukuba in Japan) were teleoperated simultaneously (in parallel). The experiment was the first general one of a research cooperation programme named TWE (Telepresence World Experiment) linking seven research teams belonging to five countries. The task consisted in assembling a four pieces puzzle. All the robots had to perform the same task at the same time. In this paper, we discuss the preliminary results of this first trial experiment and problems encountered in achieving the matter. The master consists of a high-level abstraction interface based on virtual reality concepts. The operator performed the task within a simulated environment. Based on direct hand use, the operator assembled the puzzle in a natural manner. Bilateral transformations, from the operator to robot control and backwards, from the robot to operator, with time delay considerations, are presented.

Philippe Coiffet

Papers

Virtual Reality Technology

Effect of frame rate and force feedback on virtual object manipulation

Multimodal virtual reality: input-output devices, system integration, and human factors

Human perceptual issues in virtual environments: sensory substitution and information redundancy

Parallel multi-robots long distance teleoperation