## 3 Results and Questions Analysis
### Architecture Question: Are We Doing It the Right Way?
[36] showed instead that comparing VR therapies to traditional paper and pencil therapies did not provide differences, although more intensive exercise was done in the VR group and this could have improved cognitive function. A more recent work [37] from the same researchers proved that VR therapy offered better outcomes in cognitive functioning, visuospatial ability, and executive functions compared to an adaptive paper-and-pencil environment. Additionally, we can cite the work from [PERSON] et al. [38], where outcomes suggest that combining robotic rehabilitation with VR can accelerate the improvement of the patient according to their randomized, controlled, crossover, single-blinded, or pilot study. Regarding the variability issues, we should be aware of the influence that the different tracking systems used for monitoring the patient's performance can have on the measurement of the outcome [39], and consider how the different approaches to exergaming can impact engagement and positive response, showing that collaborative gaming has better outcomes compared to cooperative and competitive gaming, although the latter can improve the sense of flow for players with higher motor skills [40]. On the other hand, other studies like [PERSON] et al. [41] and [PERSON] et al. [42] show how competitiveness can be a motivating factor, specifically for attention rehabilitation, and can improve effectiveness. Recently, [PERSON] et al. [43] collected different recommendations for the design and implementation of virtual reality for the rehabilitation of acquired brain injury (ABI): real-life, meaningful task settings, early and intensive practice of VR rehabilitation, goal-oriented, and with the ability to adapt to individual needs. The work also highlights the convenience of involving end users in the design and recommends taking into account health and safety aspects. Regarding the measurement of the results, this study includes the patient reported outcomes measurement (PROMs) in addition to measurement of clinical relevance and validity, long-term impact, etc. Finally, the heterogeneity of game design is also discussed by [PERSON] et al. [44] and [PERSON] et al. [45], explaining the impact of Presence (embodiment in the virtual environment), Motor Learning (including the richness of the definition of the environment, the intrinsic and extrinsic feedback received, the specificity of the task, training dosing and adaptability, and customization of the software for the patient), and Motivation (which promotes learning and adherence through goal setting, rewards, challenge, and narrative structure). Visual, auditory, and haptic information seems highly relevant for post-stroke rehabilitation as well. Specific VR toolkits for rehabilitation have been released recently, such as [PERSON] et al. [46], [PERSON] et al. [47], and [PERSON] et al. [48], probably making it easier and faster to build specific virtual environments aligned with existing evidence that could be used by professionals and patients, so further studies can be carried out with a larger sample size and more homogeneity of solutions and assessment approaches. Metaverse, a specific approach to VR, could become another way of applying these VR techniques to patients [49,50]. In addition, some methodologies have been designed to guide the design of VR environments and challenges--for example, [PERSON] et al. [51] for activities of daily living (ADL). In summary, there is a lot of heterogeneity in research designs, methods, techniques, measurements of the outcomes, etc., plus a lack of evidence in many cases as samples are frequently small. That is why we cannot affirm that we are doing it the right way, having different approaches with different outcomes, some with more positive results than others.