A conceptual framework for design of interactive computer play in ...

A conceptual framework for design of interactive computer play in rehabilitation of children with sensorimotor disorders Marlene Sandlund1, Kei Hoshi2, Eva Lindh Waterworth2 and Charlotte Ha¨ger-Ross1 1

Department of Community Medicine and Rehabilitation, Umea˚ University, SE-901 87 Umea˚, Sweden 2 Department of Informatics, Umea˚ University, SE-901 87 Umea˚, Sweden Background: Interactive computer play is a promising tool in rehabilitation of children. There is still little research presented in this field, and thus sparse evidence for its effectiveness. It is however evident that children, parents and therapists are in favour of this form of training and that modern motor learning theories fit very well with the concept of practising in interactive computer-based environments. There is nevertheless a need for development of new systems purposely designed for rehabilitation and this work faces substantial challenges. Objectives: In this paper we briefly present our ongoing research regarding interactive training for children with sensorimotor disorders, and reflections about challenges in the development of new interactive systems for motor rehabilitation. Methods: Interactive training using low-cost motion interactive games was evaluated with threedimensional kinematic motion analysis, clinical motor tests, physical activity monitors, interviews and gaming diaries. Conclusions: To make interactive computer play feasible in rehabilitation of children, we believe that the technique should be easily accessible in the homes of the children. Games made for the rehabilitation of children should also be flexible, partly to match the various needs of children with different disabilities, but also to enable challenging stimulation to match progress and provide variation that stimulates motivation for practice. Appropriate feedback is crucial for motivation and in order to provide this, it is important to establish optimal solutions for assessing motor control progress. Our experiences from three-dimensional motion analysis suggest that incorporating instruments for kinematic measurements into interactive games would be valuable. Keywords: Children, computer interaction, design, motor rehabilitation, virtual reality

Introduction Computer gaming is nowadays a very common leisure activity for many children and adolescents. It is not unusual for children to spend several hours a day in front of a computer, which suggests that interactive games both capture and retain children’s attention. These characteristics may make training a fun and inspiring activity that children enjoy and would want to perform often enough to achieve

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results within rehabilitation. Apart from pure motivational aspects, interactive games also hold many other features that make them interesting for rehabilitation. Practice can be performed in a gaming context that resembles real life situations, and thus allow the user to make mistakes and learn from consequences in a safe way.1,2 Interactive games can also offer the physically disabled child an opportunity to be active and independent in

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activities otherwise difficult to engage in.3 Performance in the virtual environment can also be tracked, quantified, analysed and graphically presented in order to provide user-friendly feedback and information on treatment progress to rehabilitation professionals. Interactive computer play (ICP) can be 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. This interaction may, for example, take place through a mouse or a keyboard, as in twodimensional computer games. A three-dimensional view of the generated environment, provided by helmets or goggles, can also be used, as well as interfaces that allow children to control games through body movements alone, as in video-capture games. It is also possible to use other types of interaction devices such as for example the Body Joystick, where the body is used for horizontal navigation combined with breathing for moving up and down.4 Our research group here at Umea˚ University, Sweden, is particularly interested in motion interactive games that require children with sensorimotor disorders to move their bodies in order to play, and thus in the benefits of such games in rehabilitation and for promoting physical activity in general. We have utilised commercial game environments in our initial work in this area, particularly the EyeToyTM designed to be used with the PlayStation2 platform (Sony Computer Entertainment Inc., Foster City, CA, USA). This paper will discuss our experience in the context of a conceptual framework for design of ICP in rehabilitation of children with sensorimotor disorders. In order to be clear about what researchers within this area have done and to confirm the direction of our research we started out by undertaking a systematic review to explore the use of ICP in rehabilitation of children with sensorimotor disorders. We found that the evidence for positive effects of ICP in rehabilitation of children with sensorimotor disorders is weak at present.5 Research in the field is dominated by under-powered studies, case studies and uncontrolled trials with small sample groups. Nevertheless, the main conclusions from studies included in this review are that children experience ICP as fun and motivating, and there are also some positive indications regarding movement quality, spatial orientation and mobility, playfulness and self-efficacy.

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Common applications and interactive techniques Research studies concerning computer interaction in motor rehabilitation of children have to date primarily used complex systems designed for specific therapeutic purposes and this requires the children to come to a research centre for practice (for example6,7). Our group however decided that home-based exercise with low-cost applications that are affordable for largescale use was necessary in our context. We are located in the northern part of Sweden and many of the children live in sparsely populated rural areas more than 100 km from the nearest clinical centre. We strongly believe that to fully exploit the potential of ICP in rehabilitation of children, the technique must be accessible and affordable for home-based use. Today there are no low-cost motion interactive games that are specifically designed for rehabilitation on the market. However, ordinary computer games increasingly use spatial tracking through which users interact with and control elements of the gaming world with their bodies. These new devices may prove to be excellent tools in rehabilitation. A few studies have assessed the therapeutic value of such off-the-shelf products, which are not explicitly made for rehabilitation.8–10 Adaptations of commercial systems to rehabilitation purposes for children with hemiplegia have also been reported.11 We have recently completed the data collection for a feasibility study of intervention with this type of game in home-based training for children with cerebral palsy. We are currently in the process of evaluating this experience and the result will inform the design of new training environments for rehabilitation. The EyeToy for PlayStation2 is based on a videocapture technique that utilises free body movements performed by players as input via a video camera plugged into a gaming console. Video-capture is the most frequently used interactive technique in studies with children5 and, in addition to the EyeToy, researchers have used GestureTek Inc’s GestureXtremeTM (GX) (GestureTek Inc., Toronto, Canada). These platforms were originally developed purely for entertainment and gaming purposes but the potential for rehabilitation is obvious and both systems have been tested and even compared in clinical use.10 A later development by GestureTek Inc resulted in IREXTM which is especially developed for use in rehabilitation. Despite many advantages these systems are still not widely used in rehabilitation settings. One of the major reasons for the limited usage of the IREX system is the cost of the system,

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which is not affordable for many clinical facilities and especially not for home use. Sony’s EyeToy, on the other hand, is a low-cost product that provides the opportunity to interact with virtual objects that can be displayed on a standard TV monitor, making it ideal for home practice. However, this product does not offer the flexibility needed for rehabilitation as it cannot be individually tailored to specific demands. One major weakness of the EyeToy is that it requires mainly gross motor skills and is not suitable for practice of fine motor skills. Another gaming platform that has gained much interest recently is the Nintendo WiiTM (Nintendo Inc., Kyoto, Japan). Nintendo’s approach with its ‘Wiimote’ (the Wii remote control) is a significant technological innovation in three-dimensional spatial interaction for gaming. The remote control used in the game can sense three-dimensional motion through accelerations along three axes and lets the user interact with games spatially (for example, swinging a bat, tennis racket, or golf club). The device also has an optical sensor for pointing as well as audio and vibration for feedback. The feasibility of using the Wii-system in a rehabilitation setting for adolescents with cerebral palsy has been evaluated in a case study.8 It has also been shown that adolescents’ energy expenditure whilst playing Nintendo Wii Sports was significantly greater than when playing sedentary games, e.g. Ref. 12. In our feasibility study using the EyeToy, we have utilised physical activity monitors13 to estimate the physical activity level of the children during the intervention period (see below). In both Wii and video-capture games, the players have no direct physical connection, such as cables, with the game environment. Their physical movements are detected by either the ‘Wiimote’ or by a camera. Body movements performed by players are generally in response to game-initiated events. Because their free body movements in physical space are tracked and used as inputs to the game, a merged physical/media space is created during play. This may give players a more immersive and physically challenging gaming situation, and can also produce a strong psychological feeling of presence within the merged space. This in turn may facilitate players’ performance and maintain motivation and interest in the game.14,15

Current work in progress When writing our systematic review mentioned above, we realised that very few studies have

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investigated how the motor control of children is influenced by interactive gaming. It also became clear that there is a need for efficient and sensitive methods for estimating movement quality in interactive games. The goal of the rehabilitation of children with sensorimotor disorders is often not to achieve functional improvements in a short time, especially not if impairment is congenital. Many of these children primarily practise to maintain the ability they already have. Hence, we cannot expect major motor improvement after a short intervention. It is therefore important to develop motor tests that are sensitive enough to capture small changes in motor control at the same time as being able to monitor development over a longer period. Based on this understanding we conducted the feasibility study with the long term goal of evaluating the use of interactive computer games in motor rehabilitation of children with sensorimotor disorders. The emphasis in this study was on movement control, motivation for training, and stimulating physical activity in general. This project was an interdisciplinary collaboration involving physiotherapy and informatics. The main aim of our study was to explore the feasibility and efficacy of conducting a home-based interactive gaming programme for children with cerebral palsy. Participants in the study were 15 children aged 6–16 years and diagnosed with mild to moderate cerebral palsy and with limited voluntary motor control of one or both arms. They were equipped with a PlayStation2 and the EyeToy game Play3 and encouraged to practise with the game for at least 20 min/day over a 4 week period. Throughout the 4 weeks each child, assisted by parents, filled in a gaming diary. The diary was composed of short questions with pre-determined answer alternatives and documented time spent on playing, who took initiative for playing and if the child played alone or together with parents, siblings or friends. Before and after the intervention each child, accompanied by a parent, visited the University for pre- and post-assessments that included motor tests, three-dimensional movement analysis and semistructured interviews in order to evaluate the experience of both parents and children of the interactive home-based rehabilitation programme. The movement analyses were performed with a three-dimensional kinematic motion analysis system (Proreflex, Qualisys AB, Gothenburg, Sweden) based on infrared light sensitive cameras that capture the motion of spherical reflective markers placed on anatomical landmarks on the children. This provides

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a detailed picture of the child’s motor control. One aim of the study was to investigate if kinematic assessment would be suitable to use in evaluation of training with interactive games and if so which parameters seem to be most appropriate and sensitive. Preliminary data have been presented.16 Determination of the feasibility of the intervention was based on all included assessments but in particular on information from the interviews and the gaming diary, which made it possible to evaluate both how children and parents experienced this form of training and the amount of time that the children actually practised. Children and parents involved in the study generally had positive experiences of using interactive games as part of home rehabilitation. The ability to practise at home was appreciated, and playing the games together became a pleasurable activity that both parent and child enjoyed. The parents pointed out arm-coordination and range of movement, as well as balance as particularly important aspects of movement control that could be practised in the games. Most parents were, however, not able to identify any specific physical function that improved in their child during the 4 weeks of the study. Negative aspects of the games were related to the pace of the game, which was often much too fast, making it difficult for more severely disabled children. There was also a lack of games involving more specific control of hand and finger dexterity. Results from the diaries showed that motivation was high as measured by intensity in practice and by taking the initiative to play. Children played on average 30 min/day and took their own initiative to play in the majority of all gaming sessions. In the interviews many children reported that playing together with friends or siblings was much appreciated. The outcome from the diaries supports this, since the average time for sessions played together with someone was nearly double the amount of time when playing alone. Children also liked games involving some kind of competition. The activity monitor SenseWear Pro3 Armband (BodyMedia Inc., Pittsburgh, PA, USA) was used for registration of the children’s general physical activity. The monitor was worn on the upper arm for a total of three periods of 3 days each. The first period was prior to the intervention start; the second period was during the first gaming week of the intervention; and the third period during the last gaming week. These measurements revealed that the children’s total energy expenditure and amount of steps increased from baseline to the first gaming week and also

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remained significantly higher in the last gaming week. The activity monitors were easy to use and were not cumbersome to wear for most of the children. The main concern was that a couple of children at times forgot to put on the monitor which caused some loss of data.

Considerations and challenges for future designs The experience from our current work and the challenges faced have resulted in some insights about what is important in the development of innovative interactive systems for motor rehabilitation of children. These will be discussed below along with some theoretical aspects that we believe should be central to future designs. Home-based and flexible systems

It is important to create opportunities for interactive practice for children in their own homes both to play by themselves as well as with others. If so, training may be conducted regularly and over longer periods of time as a supplement to traditional therapy. In addition, virtual applications that are internet-deliverable could open up possibilities for home-based rehabilitation which would potentially increase the involvement and motivation of the users and also reduce the financial costs associated with long periods of hospitalisation or travelling long distances to rehabilitation facilities.17 Good satisfaction with care18 as well as motor improvements19,20 have been reported by post-stroke patients undergoing a telerehabilitation programme at home. The internet may also provide a platform for disabled people through which they can communicate with others and participate in a wider community on an equal basis without being discriminated or judged because of their impairment.21 These requirements bring many challenges that need to be resolved. First, interactive games developed for therapeutic purposes need to be affordable for home-based use. Today no such inexpensive motion interactive systems made for rehabilitation are available on the market. Another challenge for the development of interactive games for rehabilitation is that children with motor disorders are a very heterogeneous group with several different types and degrees of disability which implies various requirements of the design of the games. In addition, children have high demands on the entertainment value of the games that they choose to play. These requirements must also apply to games developed for rehabilitation. This means that games made for rehabilitation of children should have a

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high degree of flexibility. One way of addressing these challenges is to utilise the vast amount of ordinary games that already exist on the market and develop new, motion interactive ways to play these games. Developing an interaction device for rehabilitation, which is compatible with commercial games, and that supports both gross motor skills and fine motor skills, would create opportunities to make interactive training as flexible and powerful as it should be in order to be a useful rehabilitation tool. Using existing games would also make it possible for children to play many different types of games, using a wider variety of movement and exercises. It would also allow them to play games of their own choice and, together with friends, maybe even on a more equal base. Motivation for practice and motor learning aspects

Motivation plays an important role in a child’s physical training as a part of rehabilitation. The child should find it enjoyable to engage in the training activities for its own sake. This is usually called intrinsic motivation.22 At the same time motivation ought also to be extrinsic, it has to bring some external reward, for example from a parent, friends and/or a therapist. It is important that the intrinsic and the extrinsic motivation are congruent in order not to contradict each other or have an opposing effect on the child. The reward must be in response to the quality of the performance as well as for merely performing the task.23 Motivation directly from the activity may, for example, be that the child gets a feeling of getting better at the game, gaining higher scores and beating an opponent. It is important that the activity creates some kind of challenge for the child and that this challenge is on the right level. It should always be possible to succeed, with some practice. Any rehabilitation involving training to improve sensorimotor function should also reflect contemporary motor learning theories in an adequate context. A fundamental factor for motor learning is feedback, such as knowledge of result of the action but also knowledge of performance of the movement.24 Other general considerations that have been highlighted especially for training of children are: motivation and prior knowledge, the context, instructions, type of task, amount of repetition, and the design of the practice sessions with variability and problem solving while also providing adequate rest.25 Feedback is crucial for motivation in the sense that information of high success rate stimulates the child to increase the physical efforts and thus to improve in performance.

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Problem solving, which is believed to take place to a greater extent in more random and complicated tasks rather than repeating simple motions in a blocked manner,26,27 is also believed to be more efficient in the long run if the learner is experienced enough with the movements to be performed.28 Highly variable practice in for instance movement distance, speed, direction and timing is assumed to lead to more generalised and adapted competence25 although the issue of how much transfer actually occurs between specific tasks is still widely debated.29 All these aspects fit very well with the concept of practising in interactive computer-based environments.30 And in such an environment children may be so immersed that the training will be performed with a much higher intensity than in traditional therapy. Mental imagery and rehearsal are other features of importance for motor learning that have been increasingly highlighted, and which have also been investigated with promising results using virtual reality in healthy subjects31 and with computer support in neurological rehabilitation after stroke.32 It is however essential to consider that it is most likely only beneficial if it is combined with carrying out real movements and can thus never completely replace physical practice, but it could possibly be a good complement.33 Assessment and evaluation

Optimally, a computer based environment used for motor rehabilitation could not only function as the training device per se, but could also be used for diagnostic and assessment purposes in rehabilitation.34 That is, end goals would be to characterise, in as much detail as possible, the specifics of the movement abilities of the individual child. This could for instance be outcome parameters such as body parts activated during the play, type of movements, range of movement, movement speed, eye-hand interaction, and endurance measures and so on. If the environment enabled monitoring over time of such measures, it would be possible to assess the current physical status of the child and to record the natural history of a disorder or to evaluate interventions of various kinds. It would be especially convenient and valuable if this occurred regularly in the child’s home environment and data could be transferred electronically via the internet to the therapist or rehabilitation team. Other quantitative measures of physical activity are for instance time spent active in the game and scores obtained by single or multiple players identified by electronic ID-tags. It would be important, however to ascertain the desired

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movement and its quality, as it is often too easy for the child to ‘cheat’ using a better hand or in various ways avoid solving the motor problems in question. For example when facing ‘learned non-use phenomenon’ it is essential to stimulate the movements that need to be practised. If appropriate methods to assess the child’s movements are integrated in an interactive game it would be possible to discover when the child is cheating and, through feedback, reward movements performed correctly. Anyway, it seems of uttermost importance to establish optimal ways of assessing progress, and to incorporate those in the ICP environment to provide feedback for both users and therapists. We call for a creative debate of these issues. Which then are the available techniques for assessing motor ability that could also be employed in ICP? One option is to use physical activity monitors13,35 and perhaps combine these with a web-based interactive training diary to monitor the child’s progress. Initially, in our own feasibility study, our goal was to use a web-based diary, but because the game we used did not have a direct link to the internet we realised that it actually took less time to fill out a paper diary than to log on to the computer. In the design of new home-based games for rehabilitation, however, it would be good to integrate an exercise diary and log files of the games played, scores obtained etc. This can be a valuable tool both for the therapist to give feedback to the child and for parents in order to motivate the child. Another technique to give immediate feedback to the child and also to accomplish long term monitoring is the use of biofeedback signals, gyros and motion capture. By using these kinds of techniques it is possible to carry out detailed movement analysis that can inform about the movement quality and suggest specific training for improvement. Kinematic data, such as those provided by the motion capture system used in our work, offer an excellent basis both to give feedback to the user and to perform more long-term evaluation or research. Integrating this type of measuring device in applications for home use has been explored with patients after stroke36 and is a challenge that we would like to investigate further with children. The disadvantage is that often a huge amount of data is generated. To be able to integrate this type of measurement in an interactive game limitations have to be made by selecting a few variables that give an adequate representation of the child’s motor skills. One aim of our study is to find such appropriate variables.

Interactive computer play in rehabilitation of children

It also requires special equipment to measure threedimensional movements and it is a challenge to develop simple methods for this without affecting the cost of the system and the usability too much. There exists today equipment for motion capture in different forms, for example suits, gloves or bands that you put on different body parts, but it would also be valuable to integrate inexpensive video-based systems for movement analysis in motion interactive games for children.

Summary The present paper presents our ongoing research regarding interactive training for children with sensorimotor disorders and some of the ideas that our projects have rendered for the development of new interactive systems for rehabilitation. We discuss the importance of home-based and flexible systems, motivation, feedback and motor learning, as well as the need for development of integrated methods for assessing motor control in interactive games. When designing future systems for ICP for rehabilitation purposes, we suggest that there should be an interdisciplinary team (e.g. physical therapy, informatics, and engineering) who participate in the process of complete system development. Equally important is that children (the target group) and parents participate in the design process; after all they are the real experts in the area. We also believe that design and development should be conducted in an ‘evolutionary’ way, involving users throughout, in order to design, check, evaluate and change the system before final implementation.

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MARLENE SANDLUND Department of Community Medicine and Rehabilitation, Umea˚ University, SE-901 87 Umea˚, Sweden Email: [email protected]

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