Special education can be defined as specially designed instruction to meet the specific needs of a child whose learning needs have not been addressed by mainstream education. Traditionally, special education has had, as a target population, students with physical, mental, intellectual, visual, and hearing disabilities. Today, special education, in certain national and cultural contexts, can also comprise the education of children with behavioral challenges and mental illnesses [Page 731]as well as the education of highly gifted children. Especially since the early 1990s, special education has been by some criticized to further the segregation of students with disabilities and therefore has been, in many Western countries, superseded by the paradigm of inclusive education.