Abstract
BACKGROUND:
In neurorehabilitation, clinicians and managers are searching for new client-centred task-oriented applications which can be administered without extra costs and effort of therapists, and increase the client’s motivation.
OBJECTIVE:
To develop and evaluate a prototype of an intelligent activity-based client-centred training (i-ACT) system based on Microsoft Kinect
METHODS:
Within an iterative user centred process, the i-ACT prototype was developed and necessary features were established for use in neurological settings. After the test trial with a high fidelity prototype, the value, usefulness, and credibility were evaluated.
RESULTS:
Seven therapists participated in focus groups and 54 persons with neurological problems participated in test trials. A prototype was established based on the user’s experience. Results show that clients and therapists acknowledge the value and usefulness (clients 5.71/7; therapists 4.86/7), and credibility (clients 21.00/27; therapists 14.50/27) of i-ACT.
CONCLUSIONS:
Therapists want to be able to record an endless range of movements and activities which enables individualised exercise programs for persons with disabilities. For therapists it is important that the system provides feedback about the quality of movement and not only results. In future work, clinical trials will be performed towards feasibility and effectiveness of i-ACT in neurorehabilitation and other rehabilitation domains.
Background
Persons with central nervous system diseases (PwCNS), such as multiple sclerosis (MS), stroke and spinal cord injury (SCI), experience loss of motor function which influences their performances of activities of daily life (ADL) [1, 2, 3, 4, 5]. To optimise rehabilitation outcome, rehabilitation should be client-centred (CC) and task-oriented (TO) [6, 7, 8, 9, 10, 11, 12, 13]. Although this approach has been proven beneficial and effective in neurological rehabilitation, implementation is difficult as it may be more time consuming for therapists, and costly for rehabilitation centres [6, 7, 8, 10, 14, 15, 16]. Therefore, clinicians and managers of rehabilitation centres are always searching for new client-centred task-oriented (CCTO) applications which can be administered without extra costs and effort of therapists, and increase the patient’s motivation [14, 16, 17, 18, 19, 20].
Technology-based systems, especially robotic systems, have already been used effectively in rehabilitation [5, 12, 13, 16, 21, 22, 23, 24]. However, they have some restrictions regarding incorporation into practice, especially in the home situation because of high costs [12, 13, 21], difficulty to use and/or install [12, 13, 21, 22, 23, 24], and the lack of possibilities to incorporate a full CC approach by offering individualised exercises. Only a few systems incorporate aspects of CC approach [7].
Other than robotics, there are off-the-shelf systems that are easy to use and low-cost, such as the Nintendo Wii and Microsoft Kinect
In order to develop low-cost, off-the-shelf technologies suitable for CC rehabilitation use, the requirements and expectations of therapists and patients towards these technologies such as MK
Method
User-centred process
A user-centred design approach was applied within an iterative process using focus groups and user tests to develop the i-ACT. The flow of the process is presented in Fig. 1. The in- and exclusion criteria are presented in Table 1. Ethical approval was obtained from the Ethical Comité of Jessa Ziekenhuis, Hasselt, Belgium (Reference number B243201420129). Written informed consent was obtained from all subjects before participation.
In phase one, focus groups with therapists (physio- and occupational therapists) were held at four rehabilitation centres in Flanders, Belgium (Jessa Ziekenhuis campus St-Ursula, Rehabilitation and MS centre Overpelt, Ziekenhuis Oost-Limburg campus St-Barbara, and MS Centre Melsbroek). During these focus groups, specific features were presented to therapists, such as criteria examples, feedback examples, visualisation of an exercise, visualisation of avatar etc. Therapists could give feedback and suggest adaptations to the presented features.
Flowchart of the user-centred process.
In- and exclusion criteria
Based on the results of phase one, engineers developed a basic version of i-ACT with adapted or new features (see results section).
Phase two consisted of user tests, organised with the basic i-ACT in two rehabilitation centres (Jessa Ziekenhuis campus St-Ursula and Rehabilitation and MS centre Overpelt), and completion of three questionnaires. The test trials were performed with PwCNS and therapists. The system was placed on a standard table of 74–75 cm high. The participants had to sit or stand at a distance of 1–3 m. Therapists were asked to record one new movement before performing 3
Based on the feedback, suggestions, and the clinical outcomes gathered during phase 2, the basic version was adapted and more features were developed towards a prototype of the i-ACT (see results section).
Focus groups were analysed using thematical analysis. Descriptive analysis of questionnaire results was executed with Excel 2007 and IMB SPSS Statistics (version 22.0; Armonk, New York, USA).
Results
Participants
Feedback and suggestions of all 61 participants in phase 2 will be described. Seven therapists participated in the focus groups. Fifty-four persons were involved in the tests. Characteristics are presented in Table 2.
Participant characteristics
Participant characteristics
Age values are means
Out of the focus groups with the therapists, 4 main topics where revealed: users’ requirements, graphic requirements, apparatus, and feedback.
Additionally 2 topics where added in the results section, “creating activities and training” and “quality of movement”, which are involved in the 4 main topics and are relevant for understanding the concept and choices made during the development of the i-ACT prototype.
Users’ requirements
For the therapists it was clear that the application should allow to 1) record and store a movement for therapists, 2) to view a movement in a 3D environment, 3) to view a real time movement of the patient, and 4) to compare the real time movement of the patient with the recorded movement of the therapist (The system or technology should give feedback to the patient. I think that sometimes patients don’t really know whether they did the exercise correct. For example, did I use enough force, did I move correctly, etc.; occupational therapist). An overview of information regarding use and implementation of specific features, setup and content can be found in Table 3.
The information gathered from the therapists during the focus group in phase 1, led to the development of a basic i-ACT version. This version consisted of a recording feature and a real time feature, but no comparison could be established. The environment was a black background with a white stickman.
With the basic i-ACT, test trials were performed with patients and therapists (phase two). From the answers of the patients in the i-ACT questionnaire, as seen in Table 3, it is clear that a lot of requirements relate to the requirements of the therapists. Furthermore, patients stated their preference to be able to practise activities (
The information of both phases was implemented in the development of the prototype, which is described in the next sections.
Therapist’s and patients’ requirements
Therapist’s and patients’ requirements
Concerning virtual setup and environment, all therapists were unanimous that the environment should be as simple as possible for patients, especially dealing with PwCNS. The environment should be simple but attractive in order to motivate persons to exercise. From the patient’s perspective, the application needed to be simple, clear and intuitive (I don’t like it when there is too much going on…I can’t focus when there is a lot to see on the screen; patient with stroke). For the prototype, a plain room scene was chosen, as seen in Fig. 2 instead of a fully equipped room, e.g. a kitchen or garden.
3D scene in therapist mode.
During the focus groups and test trials, patients expressed that there had to be a clear distinction between the background and the avatar. The latter was suggested above a stick man (which was used during the focus groups and tests), or a real image of themselves (I don’t like looking at myself. If you just put a normal looking man or puppet there, that’s fine; Patient with MS). For the prototype a simple avatar was developed (as seen in Fig. 2).
For therapists it is important to have an apparatus which is easy to set up, does not take up too much space, is easy to use (It’s ok if you spend a bit more time the first time you use it for a patient, but the next session, it should just work, so that you don’t lose time afterwards …. It should store the patients data; occupational therapist), and is not too expensive (Financially there are some possibilities for buying technology. The problem is, that is changes constantly and you have to make smart decisions so you can use the technology for longer than just one year. And most of the time, the additional licenses are the most expensive; occupational therapist). If possible, therapists prefer a system where the patient is not strapped in or sensors have to be placed on the body. Therefore, developers chose to use the MK
For the technical development of i-ACT, the cross-platform Unity3D was used. The MK
The application is built using an administrative and client model. The administrative model can be seen as the therapist, the client model as the patient.
Creating activities and training
Therapists reported that individualised training where the patient is the central component, is very important in neurorehabilitation. As mentioned before, a CCTO training is key to optimising rehabilitation outcome. To install a CCTO training programme based on the needs of the patient, therapists should be able to record and set up any activity (and as a consequence certain analytical and/or functional movements) that is important to the patient. The steps therapists need to take for recording movements and setting up exercises should be intuitive, logical, and understandable.
To go from an activity towards a training, therapists suggested to work with the terms “movement”, “exercise” and “training”, which are considered basic terms in physical exercise.
Consequently, the following jargon is implemented in i-ACT. Movement is the posture or movement recorded by the MK
The reported requirements of the therapists towards training parameters that can be used in exercises and trainings are adaptable speed of recorded movement, adaptable number of repetitions, sets and amount of rest between sets and/or repetitions, and recording of compensatory movements.
The user management is designed as simple as possible. A therapist can log in to add, delete or change movements, exercises and/or trainings. Therapist can also assign a movement, exercise and/or training to a specific client. When patients perform a training, the movements and/or exercises are provided one by one.
Quality of movement
During the focus groups, therapists suggested that it would be important to be able to change the tolerated amount of compensatory movement (range of motion (ROM)) allowed within a movement and the size of the target the patients need to reach. To address these two suggestions, point(s) of stability (i.e. body regions that are marked as areas where no movement is allowed beyond a certain bandwidth, ie to avoid compensatory movement) and point(s) of mobility (i.e. target areas where the patients have to pass during the movement trajectory in order to guide movement) were implemented.
Visually, the point of stability is a sphere around a joint. The therapist can decide the amount of spheres, the size of the sphere(s) and the joint(s). If in the real time frame the joint moves out of the sphere, it is decided that the movement at that point in time, for the given joint, is out of range. Then, the sphere turns from green to red and a textual remark is given on the screen (as seen in Fig. 3).
Point of stability in (left) and out of margin (right).
The comparison between the movement registered from the therapist and performed by the patient, allows to provide feedback on the performance of the movement. The difference between the real time movement of the patient and the recorded movement of the therapist can be considered as the quality of the movement. In theory it can be assumed that if the recorded video stream is identical to the real time video stream, the movements are equal; If the movements are equal, the quality of the real time movement is ‘perfect’ and vice versa. The difference in ROM and timing tolerated between the two movements can be seen as the margin of quality. The tolerated difference in ROM can be set by the therapist. To calculate the tolerated difference, two frames have to be compared with each other. The difficult part is to determine which frame of the recorded movement must be compared with which real time frame. In a perfect situation it would be easy: compare the first frames, than the second frames, etc. This is not applicable since it is impossible that the real time movement is moving with the exact same speed as the recorded movement. There is always a slight delay. This would result in a sort of timing game instead of monitoring the quality. Figure 4 is a simple representation of this problem. Another way to calculate the tolerated difference, is only to take the next recorded frame if the previous frame is within margin. In theory this can work, practically however, the result is a frustrated patient, trying to complete a simple exercise; The data from the MK
Comparing movements. In the situation on the bottom right, the quality of the real time movement (right) is not good since the frame is different from the recorded frame (left).
Since the stability only compares the real time view with the first recorded frame, there has to be a way of forcing the user to do the movement as shown by the recorded movement. Waypoints will have this effect, and were named mobility points or targets.
Given that the avatar on the screen is drawn notwithstanding to the body dimensions of the person in front of the MK
Representation of waypoint in user (client) mode.
Feedback regarding quality of movement during the exercise is explained above. In the i-ACT questionnaire, participants were asked about their preference regarding feedback (i.e. timing of feedback, style, and type of feedback). The responses of all participants are presented in Table 4.
User’s responses in terms of feedback
User’s responses in terms of feedback
During the exercise, visual cues on the right side of the screen to see how many movements patients have performed and still have to perform, and on the bottom of the screen a visual presentation of the training is implemented. See Fig. 6 for some of these features.
Features in user (client) mode. 1: Repetitions completed and uncompleted; 2: Visual representation of training progression; 3: Written representation of training progression; 4: Symbolic representation of training progression.
After finishing a training, results are shown in numbers and stars (up to 5 stars) representing the amount of good movements.
Results of IMI and CEQ
Results of IMI and CEQ
IMI: Intrinsic motivation inventory; CEQ: Credibility expectancy questionnaire. Scores are presented as median (Q1–Q3).
Median values of IMI and CEQ are presented in Table 5. The data from the IMI subscale value/usefulness shows that even in the early development participants value the basic i-ACT. And although both patients and therapists find i-ACT useful in neurorehabilitation, patients score higher than therapists. Data from the CEQ credibility subscale are similar: therapists score lower than patients on CEQ, respectively median of 14.50 and 21.00 on a total of 27.
The aim of this study was to develop and evaluate a prototype of an intelligent activity-based client-centred training system using an iterative user-centred process. A prototype was developed based on experiences from patients and therapists. The developed system, intelligent Activity-based Client-centred Training (i-ACT), was found valuable and useful, and patients as well as therapists believe in the i-ACT as a training tool.
For the technical development of i-ACT, the Unity platform was chosen. Unity is a typical developing tool for 2D and 3D games. The advantage of using Unity is the capability of using a game loop, objects, scripts, etc. which gives developers a fast way of designing interactive games. Although i-ACT is not a game, it requires an advanced administration interface with menus, drop down boxes, graphics, etc. These latter features are much more difficult to develop with Unity, but the choice was made in favour of a good user experience.
An important feature of i-ACT is the possibility of a wide range of exercises in order to be CC. For therapists, all the exercises must be quick and easy to perform, if possible without any interaction of the therapist. The variety of movements/exercises asks for a lot of parameters. Developing a programme with a wide range of exercises, with as less as possible parameters to adjust is a challenge.
The feedback given to the patient concerning quality of movement can be given in real time or after an exercise. Feedback after the exercise is naturally seen from a developer’s point of view. After an exercise is completed, i-ACT can analyse the movements and give the correct feedback. From a therapist’s and patient’s perspective, the feedback must be real-time. This makes the feedback-feature difficult since it is impossible to compare the complete movement/exercise. To counteract these issues, the points of stability and waypoints were created, as described above. Also, MK
Additionally to the feedback on quality of movement, therapists would like to be able to have video footage of the patient as well, even knowing that ethical considerations need to be made. This latter could not be addressed during the development process as ethical issues would interfere.
Also, in the discussions with therapists, it was suggested to implement auditory cues when a target is reached. This will be implemented in a future i-ACT version.
Furthermore, therapists suggested the implementation of multiplayer feature. This issue is considered but not implemented in i-ACT as this is in conflict with the CC approach.
During the test trials, patients expressed that there had to be a clear visual distinction between the background and the avatar. A human-like avatar was suggested above a stickman, or a real image of themselves.
The research group acknowledges that the interface and content should be made more attractive and motivational, thus a different 3D scene with another, more human-like avatar will be implemented in the future prototype. Also, the feedback for patients after exercise and/or training will be made more attractive.
The weaknesses of the i-ACT are that the system might not be as accurate as sensor-based systems in training. While the validity and accuracy of the MK
The i-ACT is not another exergame system. To the authors’ knowledge, there is no other technology-based system available that applies a full CCTO approach, provides feedback on the quality of movement, and have possibilities in rehabilitation as well as home environment [43]. Other technology-based systems that have been developed and implemented (aspects of) CC, such as TagTrainer [44], do not provide feedback regarding the quality of movement, only on the result. The systems that do provide feedback on the quality of movement, often use body worn sensors [7, 24]. Other studies based on MK
In the focus groups, therapists were positive about the features developed for i-ACT. The main concern was the virtual environment which was not yet fully developed. Most quoted statements by participants are implemented in the most recent prototype, such as possibility to change the amount of compensatory movements allowed and the size of the presented target.
The results from the clinical tests indicated that both patients and therapists acknowledge the value, usefulness and credibility of the prototype presented in the trials. The high median of 21.00 in patients, suggests that patients think that i-ACT could be a successful tool to support them in their rehabilitation. These findings are in accordance to the research by Park et al. who stated that additional VR training with Xbox Kinect
Some methodological considerations have to be made as not all participants completed the IMI; These participants answered ‘not applicable’ to the questions of the subscale value/usefulness. Their reason was that the trial was only a one time test and based on that they could not paint a clear picture of the value/usefulness of i-ACT and/or developed features. Also, focus groups and trials were held at four rehabilitation centres in Flanders (Belgium) with a selected group of PwCNS and therapists working in neurorehabilitation. Therefore no general conclusions can be drawn for the total population of neurological disorders. Furthermore, the target group should be expanded when testing the next iteration with patients and therapists.
Further development should incorporate integrating an avatar, feedback during but also after exercises with a focus on auditory and visual feedback about quality of performance. Participants suggested a combination of activities with games. The solution could be to develop an exergame where exercise and gaming are combined by performing functional movements in a game-like environment. The researchers acknowledge the fact that virtual reality increases the motivation and adherence [14, 19] but developers need to be cautious as the goal of the project is to develop a CCTO training with MK
In future work, research studies are planned to evaluate the feasibility, motivation, usability, credibility/expectancy and effectivity of i-ACT in different rehabilitation centres with a variation of disorders.
Conclusion
The prototype of i-ACT is a client-centred task-oriented training system based on Microsoft Kinect
The feedback and results from this study will be used to adjust the i-ACT further. In future work, clinical trials will be performed towards feasibility and effectiveness of i-ACT in neurorehabilitation and other rehabilitation domains.
Footnotes
Acknowledgments
The authors want to thank all participants of this study. They also thank Frederik Smolders, Lisa Pass, Stephen Beuls, Celine De Pauw, Lieze Vandevenne and Peter Feys for their contribution. This study was part of the Technology Transfer (Tetra) project “Open intelligent rehabilitation framework for client-centred functional therapy with motion detection systems” (project number 140324) funded by Flemish Government Vlaio.
Conflict of interest
None to report.
