| - VIRTUAL REALITY - |
One of our
most active areas of research is investigation of the potential of virtual
reality (VR) as an intervention tool in rehabilitation.
Virtual reality entails the use of advanced technologies, including
computers and various multimedia peripherals, to produce a simulated
(i.e., virtual) environment that users perceive as comparable to real
world objects and events. Users interact with displayed images, move and
manipulate virtual objects, and perform other actions in a way that
engenders a feeling of actual presence, and immerses their senses in the
simulated environment. Users are provided with visual, audio and, in some
instances, haptic (the sense of touch) and olfactory feedback of their
performance. These unique characteristics of virtual reality set it apart
from other engaging experiences such as watching television, reading
books, and even playing traditional computer simulation games.
Virtual
reality may be delivered to the user via a variety of different
technologies (e.g., flat screen monitor, projected 3-D image, head-mounted
display) that differ in their ability to engender a sense of immersion
within the simulated environment and a concomitant feeling of
“presence”. They also
differ in the degree to which users experience “cyber-sickness”,
VR-generated side effects that may include nausea, disorientation and
in-coordination both during and following exposure to virtual
environments. The relation between VR system attributes, immersion and
side effects is the focus of considerable research.
Relevance
of virtual reality to occupational therapy
An essential part of the
rehabilitation process is remediation of cognitive and motor deficits in
order to improve the functional ability of the patient, and to enable him
or her to achieve greater independence.
Since the ultimate goal of rehabilitation is to maximize a
patient’s independence in activities related to daily performance
skills, the functional relevance of therapeutic intervention is of
paramount importance. Occupational
therapy may be defined as interventions, which use purposeful activity
designed to promote functional outcomes for the enhancement of health and
the prevention of injury or disability.
This is achieved in two, complementary ways - repetition of the
function that is desired (known as the functional/adaptive approach) and
treatment of specific motor or cognitive impairments (known as the
remedial approach).
One of the dilemmas of
conventional occupational therapy is the limited opportunities for
implementing purposeful activities within traditional clinical settings.
For example, it is time-consuming to teach a homemaker who has
sustained a cerebral stroke to cope with cooking and self care tasks in
her own home, although this is the environment in which such instruction
would be most constructive. It is dangerous to teach an elderly man with
Parkinson’s disease to cross a busy street, yet impractical to construct
a realistic physical mock-up of such a task.
It is expensive to assemble the materials needed to teach blind
children to navigate in novel settings, yet research has shown that
greater independence in mobility has far reaching psychological and
emotional effects. For these
reasons “real life”, environmentally-valid sites are seldom used, and
realistic simulated environments are difficult to achieve.
As a result, patients have few opportunities to engage in
purposeful and meaningful tasks.
VR has the potential to be used as a novel modality in rehabilitation assessment and intervention due to a
number of unique attributes.
These include the ability to objectively measure behaviour in challenging
but safe and ecologically-valid environments, while maintaining strict
experimental control over stimulus delivery and measurement. VR also
offers the capacity to individualize treatment needs, while providing
increased standardization of assessment and re-training protocols. It
is common for patients to “practice” the use of compensatory
strategies within the traditional rehabilitation setting, in the hope that
these skills will generalize to their home environment.
However, this approach is labor intensive, limited in intensity and
duration of repetitions, and with uncertain efficacy outside of the
rehabilitation setting. VR can help to address these limitations by
allowing the development of low-cost training environments consistent with
the client’s home environment. Furthermore,
virtual environment's can provide repeated learning trials and offer the
capacity to gradually increase the complexity of tasks while decreasing
the support/feedback provided by the therapist.
Until
recently, the application of VR technology in rehabilitation was severely
limited by the lack of inexpensive, easy-to-maintain and easy-to-use VR
systems. The vast majority of
the studies carried out in the past decade used custom applications that
were relatively expensive and technically complex.
VR applications in medicine and rehabilitation are a relatively
recent occurrence made possible by technological developments that have
led to decreases in cost and increases in ease of use and in the
availability of off-the-shelf programs. For example, VR has been used to train surgical residents to
carry out of a variety of
invasive procedures such as knee arthoscopy.
Medical students have been taught to palpate tumors and to insert
epidural anesthesia. The treatment of psychological
dysfunction including phobias,
post-traumatic stress disorder, and eating and body image disorders have
been highly successful. Recently,
VR has been used as a medium for the assessment and rehabilitation of
cognitive processes, such as visual perception and executive functioning and for training instrumental activities of daily
living, such as the use of public transportation, and meal preparation tasks.
Safe
Street Crossing
Our research group first
became interested in using virtual reality in an effort to develop an
additional strategy for the treatment of unilateral spatial neglect (USN),
a phenomenon seen most often in right cerebrovascular accident (CVA) but
also present in patients following traumatic brain injury. Neglect is
defined as a behavioural disorder in which the patient fails to respond or
pay attention to a stimulus presented to the contralateral side of the
lesion. USN has major rehabilitation implications since it is known to be
associated with decreased functional independence.
More recently, in a collaborative project with Prof. Noomi
Katz (Hadassah-Hebrew University), Dr. Naomi Josman (University of Haifa),
Dr. Tzvi Weingarden (Haim Sheba Medical Center), and together with two
doctoral students, Rachel Kizony (Hebrew University) and Debbie Rand
(University of Haifa), we have commenced a series of studies using a VR
system in which it is possible to achieve varying levels of immersion, the
Gesture Xtreme VR system. Users
stand or sit in a demarcated area viewing a large monitor or projected
image that displays one of a series of simulated functional tasks, such as
catching virtual balls or swimming in a virtual ocean.
A digital video camera converts the video signal of the user’s
movements for processing by unique software.
The participant's image is processed on the same plane as screen
animation, text, graphics, and sound, which react accordingly depending on
his or her movement. This process is referred to as "video
gesture", i.e., the initiation of changes in a virtual reality
environment through video contact. The participant's live on-screen video
image responds at exactly the same time to movements, lending an
intensified degree of realism to the virtual reality experience.
The result is a complete engagement of the user in the simulated
task.
The Gesture Xtreme system is unique from other VR systems for
several reasons. First, the
user does not have to use a head-mounted display or other special
apparatus in order to feel immersed within the virtual environment.
This both reduces the likelihood of developing side effects and
eliminates a source of encumbrance that would likely hinder the motor
response of patients with neurological deficits. Second, the user views
himself actively participating within the environment rather than some
representational avatar; this has been suggested to add to the realism of
the environment and to the sense of presence.
This will enable us to determine the effect that varying levels of
immersion have on subject performance and treatment efficacy.
Third, the user controls his movements within the virtual
environments, navigating in a completely natural and intuitive manner.
Fourth, while interacting within the virtual environment, the user can use
all body parts to interact with virtual stimuli or interaction may be
restricted to a specific body part (e.g., the head or hand) when
intervention is directed in a more precise manner.
Finally, the existing scenarios provide opportunities to facilitate
a patient’s residual cognitive, motor and sensory abilities in
functionally meaningful contexts. Since
the ultimate goal of rehabilitation is to maximize a patient’s
independence in activities related to daily performance skills, functional
relevance and integration of performance components are of paramount
importance.
The Gesture Xtreme VR system was originally developed as an
entertainment system, designed to reveal the mysteries of VR in science
museums and popular expositions. It
is only via adaptations complying with principles based on rehabilitation
intervention theory that permit its use as an effective rehabilitation
intervention tool. We
have adapted the original Gesture Xtreme VR scenarios such that it is now
possible to completely control the type, speed, location and direction of
all stimuli and to record all subject performance.
These adaptations enable the integration of instantaneous movement
in the virtual environment with the recognition of specific stimuli and
the allocation of attention to them. Moreover, the ability to control the
number, speed and type of stimuli enable training of specific attention
components, for example, selective attention in cases where the user has
to touch one stimulus while avoiding another and sustained attention where
the user has to sustain attention for a long period of time.
We are currently developing an entirely new scenario, a
virtual office which will give us greater flexibility in functional
applications. It is expected
that these and other studies will demonstrate that virtual environments
will be able to provide efficient, realistic and functional settings for
an assessment and intervention in occupational therapy.
In collaboration with Prof. Albert Rizzo from the University of
Southern California's Integrated Media Systems Center, we will be
comparing how patients respond to these functional environments (e.g. an
office, a classroom and/or a store) using the Gesture Xtreme methods and
using a 3-D head-mounted display (HMD).
The combination of a HMD and tracking system allows the computer to
generate images and sounds in a virtual environment that corresponds to
what users would see and hear from their current position if the scene
were real. The user is free to walk and turn around to survey a virtual
landscape, or inspect a virtual object.
Workshop
and Symposium http://www.cri.haifa.ac.il/VR_Symposium_2002
One of our
main objectives is to promote the awareness of virtual reality as an
effective intervention tool in rehabilitation.
To this end, we have received funding from the University of
Haifa's Caesarea Edmond Benjamin de Rothschild Foundation Institute for
Interdisciplinary Applications of Computer Science to hold a workshop and
symposium in November, 2002 on the topic of “Virtual Reality and
Rehabilitation: Algorithms, Avatars and Applications”.
Researchers from Israeli and abroad will present some of the latest
developments in this field.
Journal
articles and conference papers on virtual reality
Weiss,
P.L. and
Jessel, A. Virtual reality applications to work.
WORK, 11:277-293, 1998.
Riva, G.
Rizzo, A., Alpini, D., Barbieri, E., Bertella, L., Davies, R.C.,
Gamberini, L., Johansson, G., Katz, N., Marchi, S., Mendozzi, L.,
Molinari, E., Pugnetti, L., Weiss, P.L. Virtual environments in the
diagnosis, prevention, and intervention of age-related diseases: A review
of VR scenarios proposed in the EC VETERAN Project. CyberPsychology &
Behavior, 2, 577-91, 1999.
Naveh Y.,
Katz N., Weiss P.L. The effect of interactive virtual environment
training on independent safe street crossing of right CVA patients with
unilateral spatial neglect. Proceedings of the 3rd
International Conference on Disability, Virtual Reality and Associated
technologies, Alghero, Sardinia, September, 2000.
Weiss,
P.L.,
Naveh, Y.,
and Katz, N. Design and testing of a virtual environment to train CVA
patients with unilateral spatial neglect to cross a street safely.
Occupational Therapy International, 10:39-55, 2003.
Weiss, P.L., Bialik, P. and Kizony, K. Virtual reality provides
leisure time opportunities
for young adults with physical and intellectual disabilities.
CyberPsychology & Behavior, 6:335-342, 2003.
Kizony, R., Katz, N. and Weiss, P.L. Adapting an immersive virtual
reality system for rehabilitation. Journal of Visualization and Computer
Animation, In press, 2003.
Kizony, R.,
Katz, N, Weingarden, H. and Weiss, P.L. Immersion without
encumbrance: adapting a virtual reality system for the rehabilitation of
individuals with stroke and spinal cord injury. Proceedings of the 4th
International Conference on Disability, Virtual Reality and Associated
technologies, Vezprem, Hungary, September, 2002.
Funding
Israeli
Ministry of Health
Israeli
Ministry of Defense
Avrohom and
Ida Baruch Foundation
The Israeli Foundation for Spinal Cord
Injured due to Gunshot