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Excerpts from American Association on Intellectual & Developmental Disabilities


What is a developmental disability?


Federal law defines a developmental disability as a severe chronic disability manifesting before age 22 due to physical and/or mental impairments, resulting in “substantial functional limitations in three or more of the following areas of major life activity: (1) self-care; (2) receptive and expressive language; (3) learning; (4) mobility; (5) self-direction; (6) capacity for independent living; and (7) economic sufficiency.”


The most common type of developmental disability is intellectual disability, which has replaced the outdated pejorative term mental retardation.  Other common developmental disabilities include autism, cerebral palsy (CP), certain chromosomal and genetic conditions (e.g., Down syndrome, fragile X syndrome), and multiple congenital anomalies.  Some individuals with seizure disorders, learning disorders, attention-deficit/hyperactivity disorder, and visual or hearing impairments also meet the definition for having a developmental disability.  These conditions are commonly grouped together as “IDD” (intellectual and other developmental disabilities).


What’s the current thinking about how to help people with Intellectual Disability?


The American Association on Intellectual and Development Disabilities (AAIDD) stresses that the overarching reason for evaluating and classifying individuals with intellectual disabilities is to tailor supports for each individual, in the form of a set of strategies and services provided over a sustained period.


Our goal is to enhance people’s functioning within their own environment in order to lead a more successful and satisfying life. Some of this enhancement is thought of in terms of self-worth, subjective well being, pride, engagement in political action, and other principles of self-identity.   


How are Intellectual Disability and Developmental Disability different?


Intellectual Disability is one type of a larger universe of many types of Developmental Disabilities.


Developmental disabilities are defined as severe chronic disabilities that can be cognitive or physical or both.  The disabilities appear before the age of 22 and are likely to be lifelong.


Intellectual Disability encompasses the “cognitive” part of this definition, that is, a disability that is broadly related to thought processes.  Because intellectual and other developmental disabilities often co-occur, intellectual disability professionals often work with people who have both types of disabilities.


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