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The progress in information and communication technology (ICT) led to the development of a new rehabilitation technique called “serious game for functional rehabilitation.” Previous works have shown that serious games can be used for general health and specific disease management. However, there is still lack of consensus on development and evaluation guidelines. It is important to note that the game performance depends on the designed scenario.
The objective of this work was to develop specific game scenarios and evaluate them with a panel of musculoskeletal patients to propose game development and evaluation guidelines.
A two-stage workflow was proposed using determinant framework. The development guideline includes the selection of three-dimensional (3D) computer graphics technologies and tools, the modeling of physical aspects, the design of rehabilitation scenarios, and the implementation of the proposed scenarios. The evaluation guideline consists of the definition of evaluation metrics, the execution of the evaluation campaign, the analysis of user results and feedbacks, and the improvement of the designed game.
The case study for musculoskeletal disorders on the healthy control and patient groups showed the usefulness of these guidelines and associated games. All participants enjoyed the 2 developed games (football and object manipulation), and found them challenging and amusing. In particular, some healthy subjects increased their score when enhancing the level of difficulty. Furthermore, there were no risks and accidents associated with the execution of these games.
It is expected that with the proven effectiveness of the proposed guidelines and associated games, this new rehabilitation game may be translated into clinical routine practice for the benefit of patients with musculoskeletal disorders.
Musculoskeletal disorders lead to high medical costs all over the world. These disorders affect the working performance and well-being of the involved people [
Some research studies focused on games that could improve general health for adults and elders. Chen et al (2012) developed a lower limb power rehabilitation system. Each user needs to execute a squat motion, with sufficient power, to correctly build a virtual tower made of blocks [
Parkinson disease has been a subject of interest among serious game projects. Yu et al (2011) [
Another rehabilitation field that has been studied is stroke rehabilitation. Cho et al (2014) developed a proprioception rehabilitation system for stroke patients [
Literature showed that serious games have been intensively developed for general health and specific disease management. One of the most important aspects of serious games is the game playing scenario to motivate the patient. Moreover, user acceptability also plays an important role in promoting this new technology to clinical practice. Finally, the user security aspect needs particular attention to avoid new clinical complications for patients. Different game systems have been developed and tested. There is still lack of development and evaluation consensus guidelines to achieve these important aspects. It is important to note that the game performance depends on the designed scenario. Some authors have attempted to propose specific guidelines for game development-based learning [
The development of serious games for functional rehabilitation of musculoskeletal disorders is a complex engineering task. To deal with such complexity, a two-stage workflow was proposed. The first workflow relates to the development guideline (
Rehabilitation-oriented serious game: development guideline.
Rehabilitation-oriented serious game: evaluation guideline.
This subsection describes the work done using a proposed development guideline for creating specific serious games for functional rehabilitation of musculoskeletal disorders.
The selection of available computer graphics technologies and tools plays a crucial role in the success of the rehabilitation game. To ensure a user-friendly, human-system interaction, cutting-edge technologies benefiting the most recent progress of ICT solutions need to be used. In this study, open source Blender design software (Neo Geo) was selected for human body modeling. XNA Game Studio (Microsoft) was selected as game engine. Microsoft Kinect camera was selected as human motion capture tool. Computer screen was used as human-system interface. The pertinence of these technological choices has been proven in our previous studies [
A 3D avatar model was developed using Blender design software to represent the human body. This is a 3D surface mesh model including a collection of vertices, edges, and faces that defines the external shape of the human body. Moreover, an internal skeleton structure was also created to define body segments (eg, thigh and leg) and their interaction (eg, joint) during the motion [
Games with 3D interactive objects need to establish interaction rules between them. An algorithm was designed and implemented to detect collisions between objects within the scene. The challenge was to find a way to differentiate between the detection between different avatar bones and 3D objects; therefore, we created spheres around each bone of the body (
Let S1 be a sphere with a 3D center C1(C1x, C1y, C1z) and a radius r1, and S2 another sphere with center C2(C2x, C2y, C2z) and radius r2. The distance between the 2 centers of the 2 spheres is d drawn in
This distance is computed between every 2 objects at each updated iteration during the game. If d is found to be less than the sum of the 2 radiuses r1 and r2, a collision is detected, and the game reacts to it by a certain preprogramed reaction.
Two task-oriented game scenarios (football and object manipulation) were designed and implemented. The football game aims at practicing body orientation and lower limb motions, allowing the rehabilitation of spinal and lower limb systems. The object manipulation aims to practice the upper limb and lower limb motions with a focus on the detailed hand skill. The description of each game is given in the following paragraphs.
This game requires the player to execute many consecutive gestures. First, players have to stand in front of the Kinect and the computer screen. Then, they need to target the left or right cones by pivoting their body (
In this scene, the user needs to take a flower from the given vase and put it in the other one (
Visual Studio.Net, with C# programming language, was adopted for image acquisition and processing, body tracking, object manipulation, as well as for the development of graphical user interfaces (GUIs).
Illustrations of the association of collision spheres to avatar bones (a) and object collision detection principle (b).
Football game (easy level) (a) and object manipulation game (hard level) (b).
This part presents the work done, as well as outcomes issued from the application of the proposed evaluation guideline for assessing the developed games.
The game-playing performance was evaluated by the points acquired at the end of each scenario. For the usage acceptability aspect of the designed games, a questionnaire was defined. At the end of each game scene, players were required to fill out a questionnaire. The questionnaire consists of 13 questions for each specific game scenario. The feedback focuses on the game, exercise, and user aspect. For the game, the objective, the level of difficulty, the ignorance of achievement, the attractiveness of the 3D environment and GUI, and the game management (begin, end) were investigates. For the exercise, the game instructions, the variation of scenarios, the suitability of the game to the goal, and the clearness of the feedback were examined. For the user, the motivating challenge, the possibility to make mistakes, and the security feeling were investigated.
The developed game scenarios were evaluated by a normal healthy group (10 subjects: 6 males and 4 females with a mean age of 26.8 [standard deviation, SD 5.65]), to ensure the security condition, and then evaluated by a population of 20 pathological subjects (13 males and 7 females with a mean age of 49.75 [SD 18.68]) at the “Centre Hospitalier Universitaire de Limoges” (France). The patient group included different musculoskeletal disorders (3 amputee patients, 8 hemiplegia patients, 1 hereditary spastic paraplegia patient, 1 patient with ankle arthrodesis, 1 stroke patient, 1 patient with shoulder capsulitis, 1 patient with low back pain, 1 patient with carpal tunnel, 1 patient with prosthesis, 1 patient with muscle disease, and 1 patient with walking difficulty due to a car accident). Each participant signed an informed consent agreement before playing the rehabilitation games. It is important to note that the execution of rehabilitation serious game was monitored by clinicians, to ensure the ability and the security of the patients when using this new rehabilitation tool. Each healthy subject was asked to play every level of difficulty of each game, which means a total of 6 trials per subject. Some patients were not able to try all levels or even one of the two games due to the severity of their state (amputation, leg prosthesis, and paralyses). Medical experts were given the decision to accept or decline the participation of their patient in a game or a level of a certain game. Therapists accompanied their patients by standing behind them and supporting them, to ensure their security. The duration of each game level was around 60 seconds. A rest time of around 2 min was also allowed for each participant when necessary (ie, recovery from fatigue) after each game execution. The total time of the test for one subject was equal to 20 min approximately.
For the control group, the scores did not change so much when increasing the level of difficulty for the football scenario (
Regarding the object manipulation game, the same results were noted (
For the responses to the questionnaires, 29 users (patients and healthy subjects) rated the football game, and 27 rated the object manipulation game.
Regarding the user acceptability of the evaluated games, all healthy subjects found the 2 developed games motivational, attractive, and challenging. A synthesis of the patients’ responses to the football game questionnaire is depicted in
Game performance: patient group vs. healthy control group: easy level of the football scenario.
Game performance: patient group vs. healthy control group: medium level of the football scenario.
Game performance: patient group vs. healthy control group: hard level of the football scenario.
Game performance: patient group vs. healthy control group: easy level of the object manipulation scenario.
Game performance: patient group vs. healthy control group: medium level of the object manipulation scenario.
Game performance: patient group vs. healthy control group: hard level of the object manipulation scenario.
Finally, players were asked to give some specific comments on this project and the developed games. Comments and suggestions from the patient groups are summarized as follows:
Interesting game and this game needs to be developed in bigger scales.
The games are amusing, motivational and not bad at all. It made me really move my legs.
The football scene is excellent. I am a football fan and I watch all the games.
I recommend you to force the player to hit the left cone at first and then rotate towards the right cone. This improves the efficacy of spine rehabilitation.
In my opinion this can really help patients. Even if I am not a florist!
The exercises are adapted to rehabilitation at the final stages.
The project is suitable for younger players.
The project is very fun, helps in performing rehabilitation while enjoying it. It should please young and old people.
Very attractive games.
Very interesting project for movement coordination.
The avatar's movements should be improved.
Based on these suggestions, our game scenarios were updated to take them into consideration. Note that only technical improvement feedbacks were considered in the updated version. In particular, the order of the football game, as suggested in the third comment above, was redefined to adapt to the rehabilitation of spinal patients. Moreover, avatar’s movement has been improved by using multi-sensor fusion approach [
Patients’ responses to the football game questionnaire.
Criteria | Rank | ||||
1 | 2 | 3 | 4 | 5 | |
Game: Objective/goal | 1 | 1 | 2 | 15 | |
Unclear (1) → Clear (5) | |||||
Game: Level of difficulty | 3 | 4 | 7 | 2 | 3 |
Low (1) → High (5) | |||||
Game: Ignorance of achievement | 3 | 2 | 14 | ||
Unawareness (1) → Awareness (5) | |||||
Game: Environment | 1 | 1 | 5 | 12 | |
Unattractive (1) → Attractive (5) | |||||
Game: User Interface | 3 | 2 | 14 | ||
Not user-friendly (1) → User-friendly (5) | |||||
Game: Beginning and end | 1 | 1 | 3 | 14 | |
Unclear (1) → Clear (5) | |||||
Exercises: Instructions | 1 | 1 | 17 | ||
Unclear (1) → Clear (5) | |||||
Exercises: Variation | 3 | 1 | 6 | 9 | |
Low (1) → High (5) | |||||
Exercises: Suitable for game goal | 2 | 5 | 3 | 9 | |
Low (1) → High (5) | |||||
Exercises: Feedback | 1 | 3 | 4 | 11 | |
Unclear (1) → Clear (5) | |||||
User: Motivating challenge | 2 | 2 | 1 | 4 | 10 |
Low (1) → High (5) | |||||
User: Mistake permission | 6 | 2 | 7 | 1 | 3 |
Impossible (1) → Possible (5) | |||||
User: Security feeling | 3 | 16 | |||
Uncomfortable (1) → Comfortable (5) | |||||
Total | 15 | 14 | 36 | 32 | 144 |
Serious gaming technologies target audience ranging from young to adults to the elderly population. The objective of this work was to propose development and evaluation guidelines of serious games for musculoskeletal disorders. The simplicity and challenging aspect are the main advantages of this new technology. Research studies have proposed some interesting solutions over the past decade for the “gamification” approach [
Regarding our case study, patients’ scores were lower than those of the healthy group. Some of them were not able to play the football scene because of their amputation. Others could not try the object manipulation scene because they cannot move their hands at all. In general, all of them accepted the challenge and wanted to participate in this study. Hemiplegic patients were the top testers among all patients. Medical doctors and physiotherapists thought that these task-oriented games were more adapted to this particular disorder. Previous study came to the same conclusion about the use of the task-oriented games for these patients [
The design of rehabilitation game scenarios plays a crucial role in the success of the serious game for health. The game scenario must not only be attractive but also needs to be clinically useful. In this study, a task-oriented rehabilitation game scenario was proposed. The football and object manipulation games respond to the challenging objective: patient practices rehabilitation exercises without recognizing that it is a rehabilitation exercise when playing the game. Thus, the football game allows the player to practice the two motor tasks (body rotation motion and the leg motion) and two decision-making actions (observation of time and identification of right moment). The object manipulation game allows the player to practice two motor tasks (leg and arm motion) and two decision-making actions (localization of rose or vase, and observation of time). This study suggests that rehabilitation game scenarios should be designed, implemented, and evaluated with similar strategies. The outcome of the case study confirmed the robustness and effectiveness of this strategy.
The design of a motivating, challenging, and safe serious games for functional rehabilitation requires particular attention on the development and evaluation processes. This study proposes useful guidelines to achieve this objective. Thus, the development and evaluation of the 2 developed games (football and object manipulation) followed the proposed guidelines. In general, a guideline is defined as a principle to determine a set of actions in a standard way. This study aimed to propose a coherent set of development and evaluation steps for rehabilitation-oriented serious games for musculoskeletal disorders. It is expected that this proposition may help define a development and evaluation consensus in the health-oriented serious games community. It is important to note that some published works already followed these guidelines [
Our developed system used the Kinect camera as motion capture sensor. Currently, the virtual avatar imitates player movements correctly. However, clinical experts require more precision in analyzing the joint behavior during the exercise. It is well known that the accuracy of this device is limited for joint angle estimation. A deviation range of 11° to 14° was noted for the knee joint motion [
The main limitation of the 2 developed games is the lack of evident cognitive actions, which could maximize the effect of game outcomes to better manage the functional rehabilitation of musculoskeletal disorders with cognitive impairment [
In summary, this study is an explanatory work aiming to show the usefulness and applicability of the proposed guidelines and associated serious games for functional rehabilitation of musculoskeletal disorders. However, more investigations such as a long-term evaluation campaign for effectiveness analysis and a more quantitative analysis on the user‘s engagement in the games are needed to fully validate these guidelines [
Development and evaluation guidelines dedicated to serious games for health were established in this study. The case study showed the effectiveness and usefulness of these guidelines and associated games. The developed serious game system used the Kinect camera to allow users to interact with two 3D environment scenes (football and object manipulation). Healthy subjects and patients enjoyed the games and found them challenging and amusing. In this work, we concentrated on the assessment data of the developed games. In perspective, the effectiveness and clinical relevance of these games will be studied through a long-term evaluation campaign. And, in the case of positive outcomes, this new rehabilitation game may be translated into clinical routine practice in the near future for the benefit of patients with musculoskeletal disorders.
three-dimensional
electromyography
graphical user interface
information and communication technology
standard deviation
This work was funded within the framework of EBIOMED Chair–IUIS (Institut Universitaire d’Ingénierie en Santé). This work was carried out in the framework of the Labex MS2T, which is funded by the French Government. The authors would like to thank F Chaouche and E Kleinpeter for their useful comments and help on the questionnaire development.
None declared.