# Development of a Virtual Reality-Based Environment for Telerehabilitation
## 3 Results and Discussion  
The use of VR technologies in rehabilitation has proven to have clear advantages, among which is a higher degree of patient engagement within the rehabilitation process, which further boosts efficiency [43]. This paper explored how VR can improve the rehabilitation experience for patients in remote/home settings by introducing additional safety features designed to facilitate the adoption of specific training devices. The multimodal, VR-based training interface developed here significantly improves the customization of different training exercises, tailoring them to the individual needs and rehabilitation requirements of the patient. In the virtual environment, a range of rehabilitation exercises is proposed and tested using the virtual robot and patient. Figure 12 illustrates the types of exercises that can be performed using the LegUp rehabilitation robot in the developed virtual environment:  
* **HipAbduction**--performed using the joystick (X axis) on the controller held in the right hand (Figure 11b (1));
* **HipFlexion**--performed using the joystick (Y axis) on the controller held in the right hand (Figure 11b (1));
* **KneeFlexion**--executed using two buttons located on the controller held in the right hand (Figure 11b (2)).
* **Ankle Dorsiflexion**--executed using the joystick (X axis) on the controller held in the left hand (Figure 11b (3));
* **Ankle Inversion**--executed using the joystick (Y axis) on the controller held in the left hand (Figure 11b (3));  
After performing the initial rehabilitation training exercises in the virtual environment, the proposed training program is forwarded to the LegUp experimental model, located remotely in a clinical or home setting. Experimental tests with three healthy subjects have been performed using the current setup. Figure 10 presents each subject's programmed rehabilitation plan. For example, subject 1 (S1) performs the first exercise, called Dorsiflexion, three times, which has a starting amplitude (Amp.S) of 30 degrees and a final amplitude (Amp.F) of 330 degrees, with a speed of 5 rpm in a time of 11:08 s. Figure 13 illustrates the user interface with video streaming for remote monitoring of the rehabilitation process. In this instance, the LegUp rehabilitation robot was placed in a clinical environment for closer monitoring, while the VR application and the user interface were installed on a remote PC. Encoder signals from the robot confirmed the accurate execution of the programmed exercises, validating the input from both the multimodal interface and the VR application. These systems are now ready for patient testing.  
The LegUp robotic recovery system is currently in experimental testing at the Neurology Clinic 1, where it is being evaluated by the hospital's ethics committee for inclusion in a battery of clinical trials with patients. We expect the trials to last 1 year, and upon completion, we will make the results available in a scientific article.  
The system was tested in the laboratory with healthy subjects, and the results were very good, in the sense that no incidents were recorded, the robot avoided singular configurations, and the perceived ergonomics were adequate. However, we estimate a major difference between the healthy subjects, all young people with normal weight, and future patients, usually overweight and with a lower adaptability to the positions imposed by the use of the robot, which represents a limitation of the laboratory test performed.  
Figure 12: Cont.