Which act includes children with developmental delays in its definition of disabilities?

The act that includes children with developmental delays in its definition of disabilities is PL 99-457. This legislation, also known as the Education of the Handicapped Act Amendments, was significant because it expanded the scope of services for infants and toddlers with disabilities.

PL 99-457 introduced early intervention services and specifically addressed the needs of children from birth to age 2 who have developmental delays or are at risk for such delays. This focus was crucial because it recognized that early intervention can significantly improve outcomes for children with developmental challenges and their families.

Understanding this context is important, as it highlights the shift in educational policy that acknowledges the need for support at a younger age, setting a foundation for later educational interventions. The other acts mentioned either do not specifically address developmental delays or have different focuses within the realm of special education.