The Individuals with Disabilities Education Act (IDEA)  is a United States law ensuring services to children with disabilities throughout the nation. It was last reauthorized in 2004.

IDEA governs how states and public agencies provide early intervention, special education and related services to more than 6.5 million eligible infants, toddlers, children and youth with disabilities.

In order to fully meet the definition (and eligibility for special education and related services) as a "child with a disability," a child's educational performance must be adversely affected due to the disability. According to IDEA, states must make a free appropriate public education (FAPE) available to "any individual child with a disability who needs special education and related services, even if the child has not failed or been retained in a course or grade, and is advancing from grade to grade."

There are 14 specific primary terms included in IDEA under the lead definition of "child with a disability." These federal terms and definitions guide how states define disability and who is eligible for a free appropriate public education (FAPE) under special education law. 

1. Autism (AU): 

  • A developmental disability significantly affecting verbal and nonverbal communication and social interaction, generally present before age three that adversely affects a child’s educational performance.
  • Other characteristics often associated with autism are engaging in repetitive activities and stereotyped movements, resistance to environmental change or change in daily routines, and unusual responses to sensory experiences.
  • The term autism does not apply if the child’s educational performance is adversely affected primarily because the child has an emotional disturbance (#5 below).
  • A child who shows the characteristics of autism after age 3 could be diagnosed as having autism if the criteria above are satisfied.

2. Deaf-Blindness (DB):

  • Simultaneous (occurring at the same time) hearing and visual impairments, which cause such severe communication and other developmental and educational needs that they cannot be served in special education programs solely for children with deafness, or children with blindness.

3. Deafness (DF):

  • A hearing impairment so severe that a child is impaired in processing language through hearing, with or without amplification (aids) that adversely affects a child's educational performance.

4. Developmental Delay (DD): 

  • For children from birth to age three (under IDEA Part C) and children from ages three through nine (under IDEA Part B),
  • As defined by each State, means a delay in one or more of the following areas: Physical development, cognitive (intelligence) development, communication, social or emotional development, or adaptive (daily living skills) development.  

5. Emotional Disturbance (ED): 

  • A condition exhibiting one or more of the following characteristics over a long period of time and to a marked degree that adversely affects a child’s educational performance:

    (a) An inability to learn that cannot be explained by intellectual, sensory, or health factors.
    (b) An inability to build or maintain satisfactory interpersonal relationships with peers (other students) and teachers.
    (c) Inappropriate types of behavior or feelings under normal circumstances.
    (d) A general pervasive (ongoing) mood of unhappiness or depression.
    (e) A tendency to develop physical symptoms or fears associated with personal or school problems.

  • The term includes schizophrenia. It does not apply to children who are socially maladjusted, unless it is determined that they have an emotional disturbance.

6. Hearing Impairment (HI):

  • An impairment in hearing, whether permanent or changing, that adversely affects a child’s educational performance, but is not included under the definition of "deafness."

7. Intellectual Disability (ID): 

  • In 2008, the American Association on Intellectual and Developmental Disabilities (AAIDD) recommended use of the term Intellectual Disability in place of the term Mental Retardation. For changes in language to be made in the regulations, Congress must first change it in the legislation.
  • Significantly below average general intellectual functioning, existing at the same time with below average adaptive behavior (daily living skills) and present during the developmental period, that adversely affects a child’s educational performance.

8. Multiple Disabilities (MD):

  • Simultaneous (occurring at the same time) impairments (such as intellectual disability-blindness, intellectual disability-orthopedic impairment, etc.), the combination of which causes such severe educational needs that they cannot be served in a special education program solely for one of the impairments.
  • The term does not include deaf-blindness.

9. Orthopedic Impairment (OI):

  • A severe orthopedic impairment that adversely affects a child’s educational performance.
  • The term includes impairments caused by a congenital (present at birth) anomaly, and impairments caused by disease and impairments from other causes (e.g.,cerebral palsy, amputations, and fractures or burns).

10. Other Health Impairment (OHI):

  • Having limited strength, vitality (endurance), or alertness, including a heightened alertness to environmental causes, that results in limited alertness in school, that—

(a) is due to chronic or acute (sudden onset and short duration) health problems such as asthma, attention deficit disorder (ADD) or attention deficit hyperactivity disorder (ADHD), diabetes, epilepsy, a heart condition, hemophilia, lead poisoning, leukemia, nephritis, rheumatic fever, sickle cell anemia, and Tourette syndrome; and
(b) adversely affects a child’s educational performance.

11. Specific Learning Disability (SLD): 

  • A disorder in one or more of the basic psychological processes involved in understanding or in using language, spoken or written, that may show itself in the imperfect ability to listen, think, speak, read, write, spell, or to do mathematical calculations.
  • The term includes such conditions as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia, and developmental aphasia.
  • The term does not include learning problems that are primarily the result of visual, hearing, or motor disabilities; of intellectual disability; of emotional disturbance; or of environmental, cultural, or economic disadvantage.

12. Speech or Language Impairment (SLI): 

  • A communication disorder such as stuttering, impaired articulation, a language impairment, or a voice impairment that adversely affects a child’s educational performance.

13. Traumatic Brain Injury (TBI): 

  • An injury to the brain caused by an outside physical force, resulting in total or partial functional disability or psychosocial impairment, or both, that adversely affects a child's educational performance.
  •  The term applies to open or closed head injuries resulting in impairments in one or more areas:  Cognition (intelligence), language, memory, attention, reasoning, abstract thinking, judgment, problem-solving, psychosocial behavior, physical functions, information processing, speech, and sensory, perceptual, and motor abilities.
  • The term does not apply to brain injuries that are congenital (present at birth) or degenerative, or to brain injuries induced by birth trauma.

14. Visual Impairment Including Blindness (VI):

  • An impairment in vision that, even with correction, adversely affects a child’s educational performance.
  • The term includes both partial sight and blindness.