## 2 Background and Significance  
At present, stroke remains a global challenge that must be tackled from a prevention perspective [8]. For patients, physical rehabilitation is essential to regain mobility and improve their quality of life. Within this framework, tertiary digital prevention, by means of technology, attempts to mitigate the effects of neurological diseases, such as stroke. By way of example, in Europe alone, there are several million stroke survivors who need rehabilitation and, unfortunately, this number is only expected to rise in the coming years. Traditionally in health care, rehabilitation consists pf daily sessions of exercises, in which therapists supervise patients in real time. Accordingly, in financial terms and in accordance with the European Brain Council ([[https://www.braincouncil.eu/wp-content/uploads/2018/04/Brain-Mission-Final-v2.pdf](https://www.braincouncil.eu/wp-content/uploads/2018/04/Brain-Mission-Final-v2.pdf)]([https://www.braincouncil.eu/wp-content/uploads/2018/04/Brain-Mission-Final-v2.pdf](https://www.braincouncil.eu/wp-content/uploads/2018/04/Brain-Mission-Final-v2.pdf))), the estimated cost to European healthcare systems has risen to 800 billion euros per year. In countries, like Spain, the average cost of treating a patient with ictus by specialist units is estimated at 27,711 euros per year [9]. This problem can be extrapolated to a worldwide scale and it is especially relevant in low- and middle-income countries [4]. Thus, this situation has led to medical needs that have yet to be covered [3]. That is why telemedicine tools, especially those that are designed for remote rehabilitation, have attempted to meet this challenge. In this context, the exercises performed by patients can be analyzed by a machine [10], using physical sensors for tracking joints [11,12] or computer vision techniques [13]. The latter have been traditionally based on using Kinect [14,15], a low-cost hardware solution whose effectiveness has been proved in the field of physical rehabilitation [16, 17, 18]. Using entertainment and fitness-orientated commercial games has also been tried out in order to provide home rehabilitation [19,20], although some studies indicate that there are a few adversary effects of this as the games may lack customization in terms of physical rehabilitation [21]. Some approaches are even focused on specific brain disorders, such as Parkinson's disease [22]. The aim of a study into the psychological effects of playing exergames is to measure how committed players feel [23]. Because the patient motivation is essential for rehabilitation at home, some authors have put forward gamification and serious games as a way of motivating them [24]. In this respect, the design phase is crucial, not just because they can be supervised appropriately that way, but also to guarantee their efficiency and safety [25]. Regarding the specification of methodologies for creating and designing therapeutic exergames, in [26] a four-stage approach is discussed: (i) choosing an appropriate set of exercises for therapy, (ii) implementing the primary goals in virtual exercises, (iii) transforming virtual exercises into exergames, and (iv) including secondary objectives that are characterized by the game mechanics. This methodology is based on a game engine that has been specifically designed for supporting and integrating computer intelligence methods when monitoring patients [27]. Additionally, the state of the art covers more general-purpose solutions aimed at making it easier to generate or automatize customized exergames, such as the framework that is shown in [28]. In this research, the authors envisaged designing tools to support experts in the field, such as doctors or therapists, so that they can adapt and customize games-based training programs for elderly and disabled people.