## 2 Background  
### Wearable Devices  
The term wearable devices (_wearables_) refers to compact electronic devices as well as wireless-enabled computers that are seamlessly integrated into gadgets, accessories, or clothing designed to be worn on the human body. It also includes more invasive devices such as microchips or smart tattoos, or commercial and widespread devices including smart glasses, smartphones, smartwatches, smart clothing, and smart shoes, among others [24; 25]. In recent years, wearable devices have shown the potential to overcome certain limitations of the traditional healthcare and medical assessments by harnessing digital and mobile health (m-health) technologies to progress towards efficient and personalized healthcare [26]. Moreover, these devices can facilitate long-term monitoring outside clinical settings, offering a discreet and comfortable solution [27]. Wearable devices have the ability to collect comprehensive health information while functioning as they were originally designed, like fashion or productivity devices. The collected data can be analysed using standard protocols by artificial intelligence, with the aim of identifying possible predictions of health problems [28], as well as recognising activities and detecting the context in which these activities are performed [29; 30]. Since wearable sensors are going to be integrated into clothes, accessories or applied directly to the skin, they must be designed to be practical and accepted by people in their daily lives, so the materials used in their manufacture must be highly flexible, durable, anti-allergic and lightweight [31]. Advances in materials science are driving innovation in this field and researchers are exploring the use of nanomaterials, conductive polymers and elastic electronic components, among others [32]. In addition, these devices and sensors must be resistant to daily wear and tear if they are to be used for continuous remote monitoring, so sensors must be able to withstand stretching, bending, and exposure to sweat or moisture without loss of performance [33]. There are different types of sensors that can be integrated into a wearable device, from physical health sensors to obtain electrocardiogram, pulse or electromyogram, sensors related to human movement such as accelerometers, gyroscopes or magnetometers, to environmental sensors related to temperature, humidity or luminosity [34]. The geometry and type of wearable devices is defined in many cases by the type of sensor embedded in them, giving rise to a wide variety of options. There are very small sensors that can be included in devices as thin as a sheet of paper, flexible sensors to adapt to anybody surface or sensors that need a structure such as a watch to be used [35]. In the realm of monitoring and management of neurological disorders, wearable devices have emerged as a highly effective tool [36]. These devices allow for continuous and non-invasive monitoring of a range of physiological and behavioral parameters, both in medical consultation and in free-living conditions [37; 38; 39]. Wearables have the possibility to provide an abundance of data that can support tasks such as early detection, optimization of treatment, and management of neurological disorders [40]. However, it is important to acknowledge that despite the potential advantages of this technology, their application should be complemented by professional medical supervision and should complement traditional clinical evaluations [41]. To carry out these tasks, wearable devices incorporate several core components that are common in most devices. The key hardware components include the display, which facilitates user interaction and presents information about activities to be performed, the battery, which provides the necessary power supply, and the processor, which handles computational tasks. In addition, sensors are used to gather physiological and environmental data. Storage is allocated for local data retention, and the housing encloses and protects these components.