## 4 Study Cases
### Evaluation
Once inside the environment, instructions are provided through audio and text to offer different means of representation to access the information. In the virtual environment, it is possible to encounter different avatars representing police officers who give instructions to reach the established objective when the user approaches them (see Figure 9a,b). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Participant** & **Age** & **SUS Score** \\ \hline
1 & 31 years & 100 \\
2 & 45 years & 90 \\
3 & 44 years & 85 \\ Media & 40 years & 91.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Results obtained in system usability scale per participant. Figure 8: (**a**) Initial menu of the video game “Street Simulator” with level selection and how to play options (“Seleccionar Nivel”, “Como Jugar”). (**b**) Initial instruction to know the destination to go to. To complete the activity, children with ASD have a time limit of three minutes; if they do not reach the indicated destination in that time, the activity is restarted. This time is not shown at the time of using the game; it is shown at the end of the activity so the user may know how long it took to complete it. Other restrictions within the environment are that the child with ASD cannot cross the street unless he/she is in a corner; in the case that this is ignored, a warning is issued, indicating that this is forbidden. Once the child with ASD reaches his goal, visual and auditory feedback is given according to their performance (Figure 10a), and if the child does not reach the established place, encouragement is given to keep trying (Figure 10b). To select the mechanics and dynamics, the gamification techniques selection process shown in Section 2 was followed, as described in the following section. * What are user characteristics? Users to whom this application is addressed have a moderate level of autism; their ability to receive instructions and carry them out is good. However, it is necessary to take the appropriate time for them to achieve them. * Which gamification dynamics and mechanics are the most suitable for the user according to their characteristics? This videogame is based only on the use of dynamics such as rewards, challenges and missions, based on research that has previously used these techniques in children with autism [1; 68; 69; 11; 6]. * How can we adapt these techniques according to user characteristics? Technology and video games have proven to be motivating tools to work on attention and complex communicative skills, especially in children with ASD [70]. Rewards, challenges, and missions are represented within the video game through graphical elements and representative sounds for easy identification by the child with ASD. Figure 10: (**a**) Stars awarded upon arrival at your destination and a motivational message. Good job, activity successfully completed (“Buen Trabajol Activated completada con éxito!”). (**b**) Screen displayed when you fail to reach the destination and you are encouraged to keep trying. Don’t give up! victory is near! (“Juego terminado! !No te rindas la Victoria esta cerca!”). Figure 9: (**a**) Avatar within the virtual environment providing an instruction. (**b**) Avatar within the environment indicating that it is close to its destination. Challenges and missions were established for this video game to encourage the child with ASD to complete them and continue interacting with the virtual environment. Some of the challenges established are shown in Table 5.  
Additionally, missions were created that are unlocked by completing different challenges; Table 6 shows some of the established missions.