Students with intellectual disabilities are defined as having significantly below average general intellectual and adaptive functioning manifested during the developmental period, with significant delays in academic skills. Developmental period refers to birth to eighteen (18) years of age.
The mission of the National Down Syndrome Society is to benefit people with Down syndrome and their families through national leadership in education, research and advocacy.
American Association on Intellectual and Developmental Disabilities is the professional association run for and by professionals who support persons with intellectual and developmental disabilities. AAIDD has been providing leadership in the field of mental retardation since 1876.