S. schools educated only one in five children with disabilities, and many states had laws excluding certain students, including children who were deaf, blind, emotionally disturbed, or mentally retarded" from the educational system entirely (Special education and rehabilitative services, 2007, Ed.gov). Mainstreaming special needs students reduced the social stigma of many conditions, such as mental retardation and autism, which were formally not spoken of or recognized by the wider public. This also made it easier to encourage parents to identify children who might have more minor special needs that would be helpful to address with therapy and resource room support. Now it is 'normal' for students with mild learning challenges to receive extra time on their SATs, additional tutoring, and classroom accommodations that can make significant improvements in the quality of their education.

IDEA allows for the creation of an IEP (individualized education program)...

Students may be intellectually gifted but need support in normal social actions; they may have physical challenges in addition to intellectual challenges; they may need occupational support. IEPs clarify how the school must work with and for the student, so the child can receive an education commensurate with that of his or her peers.
The most recent major change in schools has been the introduction of No Child Left Behind (NCLB) which demands statistically measurable progress for this population, often on standardized tests if the student is capable of taking such an exam. Many fear that NCLB will result in more 'standardized' special needs education and 'teaching to the test,' to bring students to state-mandated proficiency. Others praise its emphasis on accountability. Regardless, it is likely to have a significant impact on the shape of special education in years to come.

References

Special education and rehabilitative services. (2010). Ed.gov. Retrieved November 18, 2010 at http://www2.ed.gov/policy/speced/leg/idea/history.html