An Update On The Use Of Virtual Reality Technology To Improve Movement In Children With Physical Impairments
Many physiotherapy (PT) and occupational therapy (OT) interventions for children and youth with physical impairments focus on improving functional movement skills and abilities. Clinicians and researchers look for engaging and motivational interventions that may enhance children's participation in therapy. For this reason, the use of virtual reality technology as a rehabilitation intervention to improve or remediate children's movement skills is being explored in clinical practice and research.
What is virtual reality?
Virtual reality is defined as the use of interactive simulations created with computer hardware and software to present users with opportunities to engage in environments that appear to be and feel similar to real world objects and events (Weiss, Rand, Katz, & Kizony, 2004).
There are a variety of methods by which users can interact with virtual reality technology (Sveistrup, 2004). To capture this diversity, authors have coined the term "interactive computer play," defined as "any kind of computer game or virtual reality technique where the child can interact and play with virtual objects in a computer-generated environment" (Sandlund, McDonough, & Hager-Ross, 2009, p.173).
Many virtual reality systems have been developed specifically for use in rehabilitation to improve movement skills. These are often expensive systems which are limited to use in research laboratories (Deutsch, Borbely, Filler, Huhn, Guarrera-Bowlby, 2008). In contrast, computer-based virtual reality video games involving joysticks or keyboard controls are common daily entertainment for many children and youth. These two extremes have been united by the development of movement-based, low-cost and commercially available virtual reality gaming systems, which have made virtual reality technology accessible and relevant to PT and OT clinical practice (Chen et al., 2007; Deutsch et al., 2008; Flynn, Palma, & Bender, 2007; Halton, 2008; Jannink et al., 2008). Research investigating the potential of this wide range of virtual reality systems to improve movement skills in children and youth with physical impairments is the focus of this review.
How can virtual reality systems be classified?
Virtual reality systems can be classified by describing how users interact with the virtual environment and how users are represented within the virtual environment. Table 1 outlines the characteristics of these different categories and provides examples.
Immersive virtual reality
In this type of virtual reality, the user wears a head-mounted display such that they are immersed in a first-person view of a three-dimensional virtual environment. Their view of the virtual world is controlled through head movements. The virtual environment is seen at full-scale (Chau, 2009). Immersive virtual reality systems require substantial hardware and software. For example, this type of virtual reality may also incorporate the use of force feedback gloves that allow users to sense their interaction with virtual objects (Chau, 2009). These systems can be very expensive and are generally limited to research laboratory use.
Non-immersive virtual reality
This type of virtual reality refers to all systems that do not involve the use of head-mounted displays to control the user's view of the virtual environment. Instead, users view the virtual environment on a two-dimensional flat screen, and interact with it through a variety of motion-detecting interfaces.
Systems that involve total-body movement
Motion-capture, camera/video-based virtual reality
The user interacts with the virtual environment through body movements alone. Motion-capture virtual reality systems involve the use of a camera to capture the users' body movements. The user's image is seen in mirror-image view within the virtual or actual environment on a two-dimensional screen (Weiss et al., 2004). The screen also displays virtual objects with which the user can interact. There are both rehabilitation-specific and commercially-available examples of these types of systems (see Table 1).
Motion-capture, sensor-based virtual reality
The user interacts with the virtual environment using a sensor interface (e.g. remote, platform, robot, or glove). In this type of virtual reality, interaction with the virtual environment is through a type of sensor interface that the user holds, wears, or stands upon. The user is represented as an avatar within the virtual environment or is invisible within the virtual environment. There are both rehabilitation-specific and commercially-available examples of these types of systems (see Table 1).
Systems that do not involve total-body movement
Interaction with the virtual environment is via a mouse, joystick, keyboard or other device. This type of virtual reality system involves upper extremity movement to manipulate a keyboard, mouse, joystick or other device. In addition to promoting upper extremity skills, these systems can be used to improve visual-spatial planning, spatial orientation, co-ordination or memory skills. The user is invisible or is represented as an avatar within the virtual environment.
What are the potential benefits of virtual reality technology?
The use of virtual reality systems may:
- Allow for repeated and consistent practice of the same task (Rizzo & Kim, 2005; Rose, Brooks, & Rizzo, 2005)
- Enable clinicians to progress difficulty and challenge levels (Rizzo & Kim, 2005)
- Enable clinicians and researchers to easily record and analyze performance outcomes (Rizzo & Kim, 2005)
- Provide a safe environment to undertake tasks which may be difficult or unsafe in real life (e.g crossing a street, operating a motorized wheelchair) (Rizzo & Kim, 2005; Schultheis & Rizzo, 2001)
- Offer appealing games that may make therapy tasks more fun and engaging, which may increase compliance with therapy (Rizzo & Kim, 2005)
- Enhance motivation to practice which may lead to longer practice duration or more practice repetitions (Harris & Reid, 2005; Rizzo & Kim, 2005)
- Provide enhanced real-time feedback about task performance or task results which may be beneficial for learning (Holden, 2005; Rizzo & Kim, 2005)
- Be useful as home interventions involving independent practice (Rizzo, Strickland, & Bouchard, 2004)
- Provide potential for telerehabilitation, if the virtual reality system is internet-deliverable (as clinicians can monitor clients' practice from afar) (Huber et al., 2008; Rizzo et al., 2004)
What do we know about the use of virtual reality technology to improve movement skills in children with motor impairments?
We conducted a literature search for articles evaluating the use of any type of virtual reality or interactive computer play intervention to improve movement skills in pediatric populations. The search also included articles seeking to explore and understand elements of these interventions. Although many virtual reality systems have been evaluated for their potential to promote other skills (e.g. cognitive, behavioural or social skills), these areas were not the focus of this literature review. The search included publications written in English and published between 1995 and March 2009. Table 2 presents a descriptive overview of the studies within each virtual reality category.
This is a diverse field of research involving a variety of study methodologies, virtual reality systems, populations, and outcomes. A recent systematic review of the evidence for interactive computer play in the rehabilitation of children with sensorimotor disorders, which included many of the articles discussed in this report, concluded that the present level of evidence was too limited to state whether these interventions are or are not beneficial (Sandlund et al., 2009). The authors state that limitations of these studies from a quality perspective include the facts that most study methodologies involve only small numbers of participants, are in the early stages of research methods (for example, there are very few randomized controlled trials, implying lower levels of evidence according to the American Academy for Cerebral Palsy and Developmental Medicine), do not provide a great deal of information about study participants, and have not always been rigorous as to study procedures and analyses (Sandlund et al., 2009). It is difficult to make a conclusive statement about the quality of the evidence at this time (Sandlund et al., 2009). However, this is a developing field in which further research is recommended (Sandlund et al., 2009). Readers are encouraged to consult this systematic review for more detailed information about the quality of studies included in this report.
What don't we know about the use of virtual reality technology?
In order to advance this field, research involving greater numbers of participants and with more rigorous study methodologies is required. In addition to on-going research to explore the effectiveness of rehabilitation-specific virtual reality systems, other potential areas of exploration include:
- How can commercially available virtual reality gaming systems be used within rehabilitation? For which populations are they best suited? Are they effective to improve movement abilities in children and youth with motor impairments? How does their use compare to traditional interventions? What is the role of the therapist when using these gaming systems? Can these games be used as home-based therapy interventions?
- How does learning of movement skills practiced during virtual reality interventions transfer to the ability to complete real world tasks and participate in functional activities outside of therapy? As few studies have investigated this type of transfer, this is an important focus of future research.
- Similarly, it is important to study outcomes that reflect children's ability to participate in activities in their daily environments. Many current studies are primarily interested in improvement in movement abilities, but do not explore whether these improvements translate to improvements in functional activities and participation (Sandlund et al., 2009).
What are the implications for clinical practice and research?
There are many reports in the popular media describing anecdotal use of these systems in rehabilitation. However, clinicians require empirical evidence on which to base their decisions. Further research is required.
Evidence is emerging to support the use of rehabilitation-specific, motion-capture, camera-based virtual reality systems to address goals related to upper extremity function in children with cerebral palsy. There is very minimal research at the moment exploring the use of commercially available gaming systems with children with cerebral palsy to improve outcomes of functional mobility, postural control and upper extremity function.
As research in this area develops, therapists are encouraged to familiarize themselves with the movement requirements of commercially-available virtual reality gaming systems, to observe children's performance during game play, and to use their clinical judgment and experience to decide whether the use of these games in therapy is relevant to individual clients' therapeutic goals. Study findings related to energy expenditure and movement characteristics in healthy children during game play (Graves, Stratton, Ridgers, & Cable, 2008; Graves, Ridgers, & Stratton, 2008; Levac et al., 2009) provide initial information to support clinical decision-making. Therapists can undertake a task analysis to determine which aspects of virtual reality games are relevant towards promoting movement skills required by the real-life tasks and activities relevant to their clients. It is also possible to make adaptations that may also enhance the rehabilitation value of these games; for example, incorporating the use of therapy tools such as the bosu ball or weights.
When considering the use of these virtual reality gaming systems in therapy, it is important to remember that these commercially-available systems provide different types of feedback, some of which may potentially be discouraging for some children. If recommending use of the Wii™ as a home intervention, therapists should consider the potential for children to 'cheat' by discovering movement strategies that enable success at the games without the use of total-body movement. Trying out the games yourself is a good first step to enable you to decide whether you would like to integrate these games in your therapy interventions.
For parents and families
If this is an area that interests you, it is important to talk to your therapist about potential opportunities for integrating virtual reality systems within your rehabilitation program. Therapists do not yet have a great deal of evidence on which to base these decisions, but can use their clinical experience to decide as to whether trialing the use of a commercially available gaming system would be of benefit towards addressing your child's therapy goals.
The potential roles of virtual reality technology in pediatric rehabilitation is promising; however, this is a developing field and early evidence is inconclusive (Sandlund et al., 2009). New developments in rehabilitation-specific and commercially-available technology imply that opportunities to integrate virtual reality technology within rehabilitation will continue to increase. Research is required to explore the effectiveness of these interventions, their application in different populations of children and youth, and their potential effectiveness to promote participation in daily functional activities.
Update written by:
Danielle Levac and Cheryl Missiuna, CanChild, McMaster University
Want to know more?
Contact: Danielle Levac.