Wolery and Wilbers (1994) describe the various classifications of children with special needs:
"Children with disabilities can be classified in a number of ways. Perhaps the most relevant classification system deals with their eligibility for early intervention and special education services. To be eligible for such services under the Individuals with Disabilities Education Act (called IDEA--formerly the Education of the Handicapped Act), children can fit into any of the 13 defined categories that identify the type of disability: deafness, dual-sensory impairments, hearing impairments, mental retardation, multiple handicaps, orthopedic impairments, other health impairments, serious emotional disturbance, specific learning disabilities, speech (language) impairments, visual impairments and blindness, traumatic brain injury, and autism. Because of the detrimental effects of early labeling, IDEA allows states to use the category 'developmental delay' for young children with special needs. Each state has specific criteria and measurement procedures for determining children's eligibility for early intervention and special education services, including what constitutes developmental delay.
Other classifications also exist. Many children will be diagnosed by their physicians as having specific conditions and/or syndromes. For example, children may be diagnosed as having cerebral palsy, spina bifida, muscular dystrophy, and many other conditions. Children with such diagnoses may be eligible for special education services under a category such as 'orthopedic impairments.' Literally hundreds of different conditions can result in disabilities and/or developmental delays." (pp. 4-5)
For additional information, refer to the following sources: