## 1 Introduction  
All of our professional and personal activity is governed by computers and information technology, so ensuring that all people have reasonable access to them is a moral obligation. Preferences and special needs of users are becoming more and more important in the digital world [1; 2; 3]. Information providers are progressively addressing the interaction needs of many different groups of population ranging from blind people, who number 285 million in the world and are expected to increase in the coming years [4], to people with other types of disabilities, elder people with declining capacity, etc. The advances in accessibility are not only beneficial for people with permanent conditions but also for those who need to interact with systems in adverse situations (e.g., noisy places, places with bad illumination, and unstable workplaces). Terms like \"accessibility\" and \"user modeling\"pursue the same objective: the personalization and adaptation of systems to the specific needs of users to achieve an interaction adapted to the user. ISO 9241-171:2008 [5], which provides ergonomics guidance and specifications for the design of accessible software, uses the term different capabilities, rather than disability. We also use this term throughout this article to align with this ISO standard. International organizations have been working for decades on accessibility guidelines for providing adapted general interaction options to people with disabilities [6; 7] and specifically in the educational area [8]. Standardization organizations have developed standards that guide the application of accessibility principles to digital systems. For example, IMS AFA 3.0 [9] and ISO/IEC 24751-1-2-3 [10] provide technical requirements to adapt learning platforms to the personal needs and preferences of students. People with different eyesight and/or motor abilities in the arms or hands need assistive technology [11], such as screen readers, Braille devices, or personalized keyboards and mice, to access information. They also need transformations and adaptations for the presentation of data in different formats or different ways to access the data. For example, some tests are adapted for students with different visual capabilities. However, even the adaptation of these tests could not always satisfy the needs of students because of the short amount of time taken to operate it [12]. Assistive technologies help blind people and people with motor problems to access information but the effort of interaction is higher than the that of those not needing such technologies; they generally require a longer time of interaction. This extra time is independent of both the previous knowledge of users and their motivation as it concerns mere interaction tasks, e.g., using a keyboard or a mouse to increase font size requires a more frequent use of the scroll bar. Using a Braille device or a screen reader also takes a longer time, as it requires compensation for the loss of perspective in information. This extra time has a greater importance in education as students have limited allocated time for the completion of educational tasks. Therefore, students with different visual and motor capabilities actually spend a good part of the time during their learning activities interacting with assistive technology [13]. This might have a negative impact on their education, especially if teachers and instructors are not aware of the amount of extra time they require for the tasks. The characteristic of being computer-mediated is relevant because e-learning is frequently the only possible way to access education for people with different capabilities. It enables distance interaction and allows the presentation of information in different formats adapted to their needs, e.g., audio descriptions, subtitles, alternative options to non-textual content, etc.