Children and youth with disabilities. Children and youth from
ages 3 through 21, inclusive, who require special education and
related services because they have disabilities as defined in
section 602(3) of the Individuals with Disabilities Education
Act. Section 602(3) defines "a child with a disability" as one
with mental retardation, hearing impairments (including
deafness), speech or language impairments, visual impairments
(including blindness), serious emotional disturbance, orthopedic
impairments, autism, traumatic brain injury, other health
impairments, or specific learning disabilities who, by reason
thereof, needs special education and related services. The term
children and youth with disabilities may also include, at a
state's discretion, individuals aged 3 through 9 who (1) are
experiencing developmental delays, as defined by the State and
as measured by appropriate instruments and procedures, in one or
more of the following areas: physical development, cognitive
development, communication develop