## 1 Introduction  
During the last few decades, augmented reality and virtual reality technologies have been tested in order to support and boost the efficiency of medical and rescue tasks of First Responders (FRs) [1; 2; 3; 4; 5; 6]. The European projects such as FASTER [7; 8], RESCUER [9; 10; 11] and RESPONDA [5; 12] also indicate the technological interest in evaluating augmented reality technologies to enhance situational awareness and early risk identification through mobile and wearable technologies, ameliorating mission management and personalizing information delivery to FRs [7; 9]. The research [9] summarizes the implementation of an Augmented Reality (AR) interface as a component of smart helmets for First Responders (FRs). In contrast, the project [7] considers providing the AR interface through both mobile phones and AR glasses (e.g., HoloLens) by overlaying sensor-provided data onto the real-world view. The performance evaluation research [3] proposes a training framework that leverages augmented reality and virtual reality technologies to improve the accuracy and speed of task execution, which is a novel design validated in an emergency medical services use case. In order to evaluate the feasibility of innovative solutions in FR operations, the International Forum to Advance First Responder Innovation [13] has identified ten recurring global capability gaps. This list establishes essential technical requirements that will guide the development of innovative technologies specifically designed to improve the security, competence, and overall effectiveness of FRs. Between those gaps, real-time information sharing seems primordial to track the location of FRs [6; 14] as well as monitor and analyze threats and hazards. The incorporation of information available from multiple and nontraditional sources has been detected as an important capability gap, including the option to monitor physiological signs of FRs. Apart from sensor-based information, interoperable communications with FRs are supposed to enhance FRs' safety and efficiency independent of environmental conditions [15; 16]. In addition, the real-time monitoring of physiological signs of FRs can provide useful cognitive information about FRs in rescue scenarios. Indeed, recent studies evaluate the relationship between vital signs and mental task execution [17; 18], indicating that mental resources can indirectly be measured in rescue situations that are physically and mentally demanding [19]. Cognitive load, defined to measure mental resources management when dealing with novel information [20], can be an indicator to expose limited data to FRs in rescue scenarios. These measures are indispensable to prevent an overwhelming display of information for rescuers. Recent studies [10] describe the created technology to adapt information exposition to the FRs according to their cognitive processing capabilities. The success of AR user interface design strongly depends on its adaptability to its field of application [21]. Therefore, testing different prototype applications in real scenarios is necessary for validation [22]. In this context, the research [10] collects the effort to create a modular AR design that can adapt to the distinct requirements of First Responders in various rescue circumstances. It summarizes an icon system designed to represent distinct functionalities, facilitating the comprehension and integration of sensor-based and artificial intelligence-based information within their rescue context. The key to creating a personalized interface was an external dashboard manipulated by the control center that could select/eliminate the visualization of interesting functionalities according to the FR biological and environmental circumstances. The roles and tasks that FRs have to perform in rescue operations vary according to their professional capabilities and the circumstances of the accident environment.