Mental Retardation: Update 2002. ERIC Digest.
by Hourcade, Jack
Mental retardation is a complex phenomenon, and fundamental beliefs
about it regularly change over time. Mainstream professional thought today
conceptualizes it as a statement about an individual's present level of
functioning, with two primary features:
* Limitations in intelligence
* Limitations in adaptive behavior.
The American Association on Mental Retardation (AAMR), arguably the
leading professional organization in the field of mental retardation, offered
the following definition of mental retardation in 2002 in its 10th edition
of the AAMR reference manual on definition and terminology (Luckasson,
Borthwick-Duffy, Buntinx, Coulter, Craig, Reeve, et al.):
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.
This definition has been widely adopted. It forms the basis for the
definition included in IDEA, the Individuals with Disabilities Education
Act of 1990.
Intelligence may be thought of as one's overall mental ability, one's
capacity to problem-solve and learn. Assessment of intellectual functioning
has remained controversial for over a century, ever since Alfred Binet
developed the first version of what has come to be known as IQ tests. These
tests typically include a range of items that assess one's general knowledge,
vocabulary, problem- solving skills, and reasoning ability.
Most IQ tests are structured so that a score of 100 is considered average.
The determination, then, of what is considered to be a "significant limitation
in intellectual functioning" remains somewhat arbitrary, the equivalent
of a line in the sand. Prior to 1973, the recommended IQ cut-off score
for mental retardation was 85. In 1973, that was revised downwards to approximately
70, where it remains today. This is roughly the lowest scoring 2% of the
The low IQ score alone is insufficient for a diagnosis of mental retardation.
It must co-exist with limitations in adaptive behavior. Adaptive behavior
refers to those social and practical skills that people use to effectively
function in their everyday lives. These include skills in such areas as
communication, social interactions, taking care of oneself, managing money,
and using transportation, among others. Various tests of adaptive behavior
assess skills by either observing the individual in situations where these
skills are required, or by interviewing those who know the individual well.
An accurate diagnosis of mental retardation thus requires three components:
* An IQ score of approximately 70 or below
* A determination of deficits in adaptive behavior
* Origins of the disability prior to age 18.
LEVELS OF MENTAL RETARDATION
Traditionally mental retardation has been divided into four levels of
severity, based largely on IQ scores:
* Mild mental retardation: IQ scores from 70 to 55/50
* Moderate mental retardation: IQ scores from 55/50 to 40/35
* Severe mental retardation: IQ scores from 40/35 to 25/20
* Profound mental retardation: IQ scores below 25/20
Typically these levels are used more in clinical settings. In school
settings, terms such as "severe disabilities" or "profound disabilities"
are more commonly found.
In 1992 the AAMR proposed a reconceptualization of levels of mental
retardation based not on IQ scores, but instead on the level of support
the individual requires in order to function successfully in society. This
system included the following four levels:
* Intermittent support (episodic need)
* Limited support (needed for specific periods of time)
* Extensive support (needed regularly for an extended period of time)
* Pervasive support (life-long, intense need).
To date this "levels of support" system has not been accepted as widely
as the traditional system based on IQ scores (Conyers, Martin, Martin,
& Yu, 2002).
Approximately 1% of school-aged children presently are receiving special
education services under the category "mental retardation" (U.S. Department
of Education, 2000). This figure has declined significantly over the past
25 years, perhaps because diagnosticians are more skilled in differentiating
these individuals from those who have other disabilities such as autism
and attention deficit hyperactivity disorder (ADHD). In addition, there
may be some reluctance to make a diagnosis of "mental retardation" due
to increasing stigma associated with that term.
Individuals with mild mental retardation typically do not have any specific
physical or medical cause for the limitations in intellectual functioning
and adaptive behavior. In these cases the cause is more likely to be heredity
(parents who themselves were below average in intelligence), early environment
(lack of linguistically and intellectually stimulating experiences), or
some combination thereof. One significant exception to this is fetal alcohol
syndrome, wherein women who drink alcohol during their pregnancies are
at high risk of giving birth to babies with mild to severe intellectual
impairment, as well as other problems such as ADHD.
As a general rule, the more severe the mental retardation is, the more
likely it is to have an identifiable medical or physical cause. These include
chromosomal abnormalities such as Down Syndrome and Fragile X, metabolic
disorders, and other conditions that result in insult and injury to the
brain and central nervous system.
In general, people with mental retardation are less efficient at learning
than are other people. This impairment in learning efficiency is roughly
consistent with overall IQ level. Specific cognitive deficits often exist
in such areas as memory, attention, or language.
In addition, individuals with severe mental retardation are more likely
to have brain damage, which in turn is associated with such physical disabilities
as cerebral palsy and seizure disorders (epilepsy) and their associated
EDUCATIONAL AND ADULT PROGRAMS
IDEA entitles every child with mental retardation from age 3 through
21 to a free appropriate public education through an individualized education
program (IEP). School is more than the acquisition of academic skills.
It provides all students, including those with mental retardation, with
the opportunities for social development. Classroom programs such as "Study
Buddies" or peer tutors can help students with mental retardation by pairing
them with selected classmates in cooperative learning arrangements to facilitate
the acquisition of both academic and social skills.
Students diagnosed with mental retardation and receiving special education
services should be provided with access to the general education curriculum,
so that they can interact with and learn from and alongside typical classmates.
This can be achieved through accommodations and modifications to the classroom's
curriculum and instruction. Special attention should be given to the development
of functional academic skills for these students. Functional academics
refer to reading and mathematics skills that are used frequently in everyday
life (e.g., reading signs or instructions, counting change, or taking measurements).
As these individuals move to secondary education settings, the curriculum
should take on a stronger career preparation and life skills emphasis.
With appropriate preparations, even individuals with severe intellectual
disabilities can acquire vocational skills, and as adults can move into
productive roles in the work place. It is increasingly expected that adults
with mental retardation will work in inclusive work settings alongside
typical workers with supports provided there as needed, and that these
individuals will live in residential programs that represent the sorts
of homes that most people live in.
THE FUTURE OF MENTAL RETARDATION
The term "mental retardation" has been the term of choice for individuals
with significant limitations in intellectual functioning and adaptive behavior
for many decades now. However, as was the case for its predecessor term
"mental deficiency" (or even earlier, such terminology as "idiot," "imbecile,"
and "moron"), over the past few years the term "mental retardation" has
lost much professional acceptance.
For example, in 1953 the National Association for Retarded Children
was formed. Through the years and several name changes the term "retarded"
was retained in the name of that organization until 1992. At that time
the organization name was changed to simply "The Arc," eliminating any
reference to mental retardation.
In 2002 the Council for Exceptional Children's Division on Mental Retardation
and Developmental Disabilities voted overwhelmingly to change its name
to The Division on Developmental Disabilities (Stodden, 2002). In deciding
to remove the term "mental retardation" from their name, they concluded
that the term:
* Was offensive
* Excluded many individuals with cognitive and intellectual disabilities,
including those with autism
*Had been replaced by many states with such terms as intellectual impairment
or cognitive disability.
Similarly, the American Association on Mental Retardation is presently
engaged in extensive discussions concerning a potential organizational
name change, perhaps to "The American Association on Intellectual Disabilities."
While a final decision had not been reached by October 2002, it appears
likely that the change will occur.
Names and terminologies change over time. However, this must not be
allowed to distract professionals and families from what should be the
paramount concern. Individuals with mental retardation must be provided
the types and levels of supports in school, work, and residential environments
that will enable them to enjoy the same quality of life that is available
to others in society.
American Association on Mental Retardation (AAMR) http://www.aamr.org/
The Arc http://www.thearc.org/
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