Students served by IDEA are distributed among 13 disability categories. Following is a brief description of each category (see U.S. Department of Education, 1999). Individual states may use different terminology.

  • Autism: Autism is a severe, lifelong disability manifested within the first 3 years of life. Major characteristics include impairments in communication, learning, and reciprocal social interaction.
  • Deafness: Individuals with deafness have hearing impairments so severe that processing linguistic information through hearing is severely limited, with or without amplification, and educational performance is negatively impacted.
  • Deaf-blindness: Individuals in this category have moderate to severe impairments in both vision and hearing. This is included as a separate category because of the unique learning needs presented and specialized services required.
  • Emotional disturbance (or serious emotional disturbance): This category includes individuals with a condition in one or more of the following areas during an extended period of time: (a) inability to learn, not due to intellectual, sensory, or health problems; (b) inability to build and maintain social relationships with peers and teachers; (c) inappropriate behavior and affect; (d) general pervasive depression or unhappiness; (e) tendency to develop fears or physical symptoms associated with school and personal problems; and (f) schizophrenia. According to the federal definition, emotional disturbance is not intended to apply to socially maladjusted children unless they are also characterized as having serious emotional disturbance.
  • Hearing impairments: Hearing impairments can range from mild to moderate to severe. The hearing loss, with or without amplification, affects educational performance and developmental progress. The impairment may be permanent or fluctuating, mild to profound, unilateral or bilateral. Individuals with hearing impairments are also referred to as “hard of hearing” or “deaf.”
  • Mental retardation: Mental retardation describes significantly below average intellectual functioning, as well as concurrent deficits in “adaptive behavior” (age-appropriate personal independence and social responsibility). Individuals with mental retardation may exhibit generalized problems in learning, memory, attention, problem solving, academic, and social functioning. It is manifested between birth and age 18 and negatively affects educational performance.
  • Multiple disabilities: This category includes any individuals with two or more disabling conditions. However, this category often includes mental retardation as one of the categories and is usually used when disorders are serious and interrelated to such an extent that it difficult to identify the primary area of disability. It does not include deaf-blindness.
  • Orthopedic impairments: Orthopedic impairments are associated with physical conditions that seriously impair mobility or motor activity. This category includes individuals with cerebral palsy, or diseases of the skeleton or muscles, and accident victims.
  • Other health impairments: This category includes chronic or acute health-related difficulties that adversely affect educational performance and is manifested by limited strength, vitality, or alertness. It can include such health problems as heart conditions; sickle-cell anemia; lead poisoning; diabetes; HIV, the virus that causes acquired immune deficiency syndrome (AIDS); or AIDS itself.
  • Specific learning disabilities: This refers to a disorder in one or more of the basic psychological processes involved in understanding or using spoken or written language, which can result in difficulties in reading, writing, listening, speaking, thinking, spelling, or mathematics. The term learning disabilities does not apply to children with learning problems that are primarily the result of visual, hearing, or physical disabilities; mental retardation; emotional disturbance; or environmental, cultural, or economic disadvantage.
  • Speech or language impairments: A disorder of articulation, fluency, voice, or language that adversely affects educational performance or a severe communication deficit that may require the use of an augmentative or alternative communication system such as sign language, communication boards, or electronic devices.
  • Traumatic brain injury: Traumatic brain injury is an acquired injury to the brain due to external force resulting in a total or partial disability or psychosocial impairment, or both, which negatively affects educational performance.
  • Visual impairments including blindness: A visual impairment is a loss of vision that, even when corrected, affects educational performance. It may be mild to moderate to severe in nature. Students who are blind are unable to read print and usually learn to read and write using Braille. Students with low vision can usually read when the print is enlarged sufficiently.

In addition, children aged 3 to 9 can be classified as experiencing developmental delay, if they are experiencing developmental delays in one or more of the following areas: physical, cognitive, communication, social or emotional, or adaptive development, and who need special education and related services.