# A Case Study on the Design and Implementation of a Platform for Hand Rehabilitation
## 5 Results
### Patient Viewpoint  
In the following Subsection, we provide several use-cases of why such a design of rehabilitation aid is useful and what advantages we gain using our ideas. In rehabilitation centers such as Changshu No.2 People's Hospital in Suzhou City (Jiangsu Province, P.R.China), it is always a problem to take care of all who need rehabilitation therapy. The constant shortage of staff is not only a problem in Changshu hospital; similar rehabilitation centers face this problem elsewhere in the world. Rehabilitation aids with similar effect as RehabHand (Kinect, VR, etc.) provide an opportunity that therapists can treat several patients simultaneously. Given exercises to rehabilitation aids, patients can work autonomously to a limited extent, while therapists supervise, observe, and guide several patients through the treatment simultaneously. Besides, during our pilot study, therapists confirmed that the rehabilitation hand is a useful aid during the rehabilitation process and reduces their effort. Note that the therapist already uses several tools during the treatment. Some are very simple, for instance, a squeeze ball. A ball to squeeze into the palm with fingers can be used to strengthen hand and finger grip. Patients need to squeeze the hand as hard as possible and hold it there for a few seconds. Patients need to repeat this several times (for instance, 10 times, it depends on the injury, age, power). Another similar exercise with the squeeze ball is pinch strength. Patients pinch the ball between finger and thumb tips and hold it for a few seconds (i.e., 60 s). Again, patients do the repetition with this exercise. These simple tests need to be done with caution to prevent further damage. Pace, number of repetitions, and so forth, need to be controlled by the therapist. In our case, we used a bionic arm to define the guidelines for a patient (see it in Figure 9 between the patient and the therapist). Patients observe the bionic hand and repeat as indicated. The implementation example in Figure 10 shows a rehabilitation hand, which we made during the creation of the RehabHand platform with local production, and used for our demonstration purpose. The idea was to make a simple (to make and to use)  
Figure 9: Bionic arm with RehabHand software usage in action. robotic hand that is self-explanatory and intuitive for the patient. Another criterion was simple electronics. A simple and fast 3D model for production that does not require high tolerances is the next advantage. Each finger is controlled with one actuator. Complexity increases exponentially with each additional degree of moving space. Our rehabilitation hand uses small servo motors that do not require additional motor drivers. The size of the rehabilitation hand is adjusted to accommodate the motors. Arduino is used for controlling motors. Specifically, Arduino Nano was chosen because of its small size. The programs in Figure 4 were prepared for this rehabilitation hand. Finding new innovative solutions for rehabilitation is inevitable, and some argue it is even good to engage patients in the process of co-designing assistive technologies [50; 51; 52; 53]. The participant became engaged in a personal innovative process, starting to deploy everyday objects as assistive devices. Our study contributes to Reference [50]; we believe local production with 3D printing of specific parts of rehabilitation aids opens up a way to home usage and affordable rehabilitation solutions. We envision a rehabilitation aid constructed from accessible software and hardware with local production, and want to give a solid ground with our architecture and design to future rehabilitation aids. Our design can be reused, not only for rehabilitation aids, but for many assistive technologies. As already mentioned in Section 4, a rehabilitation hand is one example of patients' interaction systems. Exercises written with Domain-Specific Language can serve as an intermediate layer for several services or devices needed in the rehabilitation process.