Definitions of Mental Retardation and Developmental Disabilities from Various Sources
American Association on Mental Retardation, www.aamr.org
"Mental retardation is a disability characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social, and practical adaptive skills. This disability originates before age 18."
Individuals with Disabilities Education Act (IDEA)
Our nation’s special education law, the Individuals with Disabilities Education Act (IDEA), defines mental retardation as, “...significantly subaverage general intellectual functioning, existing concurrently with deficits in adaptive behavior and manifested during the developmental period, that adversely affects a child’s educational performance.” [34 Code of Federal Regulations §300.7(c)(6)]
National Dissemination Center for Children with Disabilities, NICHCY (formerly known as the National Information Center for Children and Youth with Disabilities), www.nichcy.org
"Mental retardation is a term used when a person has certain limitations in mental functioning and in skills such as communicating, taking care of him or herself, and social skills. These limitations will cause a child to learn and develop more slowly than a typical child. Children with mental retardation may take longer to learn to speak, walk, and take care of their personal needs such as dressing or eating. They are likely to have trouble learning in school. They will learn, but it will take them longer. There may be some things they cannot learn."
The Arc of the United States, www.thearc.org
An individual is considered to have mental retardation based on the following three criteria: intellectual functioning level (IQ) is below 70-75; significant limitations exist in two or more adaptive skill areas; and the condition is present from childhood (defined as age 18 r less) (AAMR, 1992).
Developmental Disability Resource Center, www.ddrcco.com
"A developmental disability is a disability that is manifested before the person reaches 22 years of age, which constitutes a substantial disability to the affected individual, and is attributable to mental retardation or related conditions which include cerebral palsy, epilepsy, autism or other neurological conditions when such conditions result in impairment of general intellectual functioning or adaptive behavior similar to that of a person with mental retardation. Unless otherwise specifically stated, the federal definition of "Developmental Disability" found in 42 U.S.C. 6000, et seq., shall not apply.
"Impairment of general intellectual functioning means that the person has been determined to have an intellectual quotient equivalent which is two or more standard deviations below the mean (70 or less assuming a scale with a mean of 100 and a standard deviation of 15), as measured by an instrument which is standardized, appropriate to the nature of the person's disability, and administered by a qualified professional. The standard error measurement of the instrument should be considered when determining the intellectual quotient equivalent. When an individual's general intellectual functioning cannot be measured by a standardized instrument, then the assessment of a qualified professional shall be used.
"Adaptive behavior means that the person has overall adaptive behavior which is significantly limited in two or more skill areas (communication, self-care, home living, social skills, community use, self direction, health and safety, functional academics, leisure, and work:, as measured by an instrument which is standardized, appropriate to the person's living environment, and administered and clinically determined by a qualified professional.
"Similar to that of a person with mental retardation, in regard to adaptive behavior, means that a person's adaptive behavior limitations are a direct result of or are significantly influenced by the person's substantial cognitive deficits and may not be attributable to only a physical or sensory impairment or mental illness."
Developmental Disabilities Assistance and Bill of Rights Act of 2000, Public Law 106-402
(A) IN GENERAL The term “developmental disability” means a severe chronic disability of an individual that -
(i) is attributable to a mental or physical impairment or combination of mental and physical impairments;
(ii) is manifested before the person attains age 22;
(iii) is likely to continue indefinitely;
(iv) results in substantial functional limitations in 3 or more of the following areas of major life activity:
(II) Receptive and expressive language,
(VI) Capacity for independent living
(VII) Economic self-sufficiency; and
(v) reflects the individual’s need for a combination and sequence of special, interdisciplinary or generic services, individualized supports, or other forms of assistance that are of lifelong or extended duration and are individually planned and coordinated.
(B) INFANTS AND YOUNG CHILDREN An individual from birth to age 9, inclusive, who has a substantial developmental delay or specific congenital or acquired condition, may be considered to have a developmental disability without meeting 3 or more of the criteria described in clauses (i) through (v) of subparagraph (A) if the individual, without services and supports, has a high probability of meeting those criteria later in life.