## 3 Results
### Requirements  
Throughout the different phases of the research, different requirements were identified based on the therapists' feedback. Table 3 provides an overview of the proposed requirements. These requirements were partially included within the overall concept, design, and prototypical implementation of the serious game.  
One important aspect is the possibility of reviewing the performance/movements of the patients. This might be conducted differently, e.g., through streaming (R01). The game should be easy to use and understand for patients (R02) and deliver clear and precise instructions on how the movements should be performed and how the exercises should be conducted (R03). In addition, the achieved goals should be displayed for motivational purposes, e.g., a successful combination of items (R04). Since different patients require individual difficulty settings (e.g., at the beginning of rehabilitation or the end), this should also be incorporated (R05). Therefore, general game settings should also be adaptable to individual needs (R06). The overall game and its underlying mechanics should also serve as motivation for patients and not demotivate users, e.g., when they are not yet able to do something (R07). The exercises that need to be performed while playing the game should be performed correctly (R08)--badly or incorrectly performed movements may have a negative impact on the healing process. Patients suffer different and individual pain types while performing movements. This must also be incorporated within the game, i.e., a patient should only perform movements when not experiencing severe pain (R09). One problem that might arise while performing exercises is hand swelling, which should result in stopping the exercises (R10). The game should be stoppable at any point if complications arise, e.g., the patient is not feeling well (R11). The exercises should also include the upper extremities' distal and proximal movements (back and forth to the body center) (R12). Patients should also provide information about their well-being or pain during playing, e.g., to adapt or check exercises (R13). Overall, the game sessions should be limited to 15 min each--too much exercise is counterproductive (R14). Exercises involving symmetrical or coordinated movements should be included, specifically to stimulate or engage neurons (R15).  
Besides these identified requirements, the goals of this solution were also formalized by therapists as follows: (A) Work reintegration and everyday coping. (B) Swelling and pain reduction. (C) The range of motion after successful therapy should be equivalent in a side-by-side comparison. (D) It should be usable for patients with complex regional pain syndrome (CRPS).  
\begin{table}
\begin{tabular}{c c c} \hline
**ID** & **Description** & **In Prototype** \\ \hline R01 & Review possible (via streaming) for therapist & Y \\ R02 & Game should be easy to use and easy to understand & P \\ R03 & Good and clear/precise instructions should be given & P \\ R04 & Achieved goals should be displayed & P \\ R05 & Difficulty should be adaptable to user needs & N \\ R06 & Game setting itself should be adaptable & N \\ R07 & Game and mechanics need to be motivating for the patients & Y \\ R08 & Exercises should be performed correctly & Y \\ R09 & Pain thresholds of patients should be considered & P \\ R10 & Control of hand swelling must be incorporated & N \\ R11 & Game should be able to be stopped in case of complications & Y \\ R12 & Involvement of the upper extremities from distal to proximal & Y \\ R13 & Patient survey on well-being and extent of pain during exercises & N \\ R14 & Game sessions should not be longer than 15 min & Y \\ R15 & Symmetric movements for neurons & P \\ \hline \end{tabular}
\end{table}
Table 3: Identified requirements gathered from the therapists and their inclusion within the prototype (Y = included, N = not included, P = partially included).