The concept of disability englobes a broad range of cognitive and physical conditions. In addition to the wide diversity of disabilities that are medically categorized, it is essential to understand that each person has their own personal experience and understanding of their disabilities. Two people, each hearing impaired, will probably differ on some topics, ways to deal with challenging situations, and their overall opinions on disability. Thus, disability is a spectrum: though there are formal diagnoses, classifications, and legislations on the topic, one cannot and should not generalize someone’s symptoms and experience to the general population associated with their condition.

     There are two concepts related to this idea. Firstly, the one of invisible disabilities. Though some symptoms of some disabilities can be noticeable by others (i.e., the use of a wheelchair), it is crucial to keep in mind that disabilities are not necessarily visible. Thus, one can never assume knowing someone else’s situation from their outward appearance. Additionally, because some disabilities are invisible, they are easy to forget for those in the person’s surroundings. One should not take it personally if reminded of it, and rather correct their behavior and language to make the situation accessible.

     Secondly, having one disability does not exclude one from having another. One can therefore have multiple disabilities. The nature of those disabilities can be the same (i.e., multiple neurodevelopmental disorders) or significantly different (i.e., a neurodevelopmental disorder and blindness), both visible and invisible. In line with this idea, this handbook does not aim to represent the subtleties personal to each person with a disability but rather give an overview of the most important information related to each condition (symptoms, consequences), what it means for students and which accommodations can be helpful.