ARTICLE The Sony PlayStation II EyeToy: Low-Cost Virtual Reality for Use in Rehabilitation Debbie Rand, OT, PhD, Rachel Kizony, OT, PhD, and Patrice (Tamar) L. Weiss, OT, PhD Abstract: The objective of this study was to investigate the potential of using a low-cost video-capture virtual reality (VR) platform, the Sony PlayStation II EyeToy, for the rehabilitation of older adults with disabilities. This article presents three studies that were carried out to provide information about the EyeToy’s potential for use in rehabilitation. The first study included the testing of healthy young adults (N = 34) and compared their experiences using the EyeToy with those using GestureTek’s IREX VR system in terms of a sense of presence, level of enjoyment, control, success, and perceived exertion. The second study aimed to characterize the VR experience of healthy older adults (N = 10) and to determine the suitability and usability of the EyeToy for this population and the third study aimed to determine the feasibility of the EyeToy for use by individuals (N = 12) with stroke at different stages. The implications of these three studies for applying the system to rehabilitation are discussed. Key words: stroke rehabilitation, virtual reality, projected video- capture, low-cost system (JNPT 2008;32: 155–163) INTRODUCTION R ecent studies of neural plasticity and motor function retraining suggest that multiple repetitions of movement are essential to regain function. 1,2 A great disparity exists between the number of repetitions experimental animals are required to do (400 – 600 repetitions per day) compared with the number of times a movement or task is practiced during rehabilitation therapy as documented by observation of par- ticipants with stroke who received occupational and physical therapy at an outpatient rehabilitation clinic. 3 For example, during a single session of upper extremity therapy, there were only 39 repetitions of active movement, 34 repetitions of passive movement, and 12 repetitions of purposeful move- ments. 3 This limited amount of practice decreases still further once clients finish their active rehabilitation programs, an outcome that is alarming in view of the early discharge policy implemented in many countries to reduce hospitalization costs. 4,5 Moreover, most clients do not exercise by them- selves between sessions or when they are at home after discharge. Increasing the intensity and duration of rehabilitation to improve the quality of life of individuals with chronic dis- eases such as stroke can be achieved through physical activity because it reduces morbidity and prevents the development of secondary chronic diseases. 6,7 Novel methods are needed to provide opportunities for functional activities that will in- crease the number of repetitions of purposeful movements during therapy and will support the implementation of home exercise programs. 3 Maintaining the motivation of people to exercise independently at home is a related challenge because many exercise programs are monotonous and boring. 8 Virtual reality (VR)– based therapy appears to provide an answer to these challenges. VR typically refers to the use of interactive simulations created with computer hardware and software to present users with opportunities to engage in environments that appear and feel similar to real-world ob- jects and events. 9,10 Users interact with displayed images, move and manipulate virtual objects, and perform other actions in a way that immerse them in the simulated envi- ronment thereby engendering a subjective feeling of presence in the virtual world. To achieve a stronger feeling of pres- ence, users are provided with different feedback modalities such as visual and audio feedback. 11 Depending on the characteristics of hardware, software, and task complexity, VR-based therapy aims to provide users with a meaningful experience in the context of the user’s therapeutic objectives. VR is considered appropriate for rehabilitation because of its well-known assets. These include the opportunity for active learning, which encourages and motivates the partici- pant, 12 the ability to objectively measure behavior in a chal- lenging but safe and ecologically valid environment while maintaining strict experimental control over stimulus delivery and measurement. Another asset is the capacity to individu- alize treatment needs while gradually increasing the complex- ity of tasks and decreasing the support provided by the clinician. 13,14 Several studies have reported that participants experienced high levels of enjoyment while interacting within virtual environments developed for rehabilitation 14,15 and achieved a high degree of repetitions. 16 This may lead to greater motivation to exercise more 17 between sessions or at home. For the past few years, a number of clinical research groups have explored the therapeutic potential of Gesture- Tek’s Gesture Xtreme and its rehabilitation counterpart, IREX VR (www.geturetekhealth.com). IREX is a projected Laboratory for Innovations in Rehabilitation Technology, Department of Occupational Therapy, University of Haifa, Mount Carmel, Haifa, Israel (D.R., R.K., P.L.W.). Address correspondence to: Debbie Rand, drand@univ.haifa.ac.il; drand3 @gmail.com Copyright © 2008 Neurology Section, APTA ISSN: 1557-0576/08/3204-0155 DOI: 10.1097/NPT.0b013e31818ee779 JNPT • Volume 32, December 2008 155