Mental Retardation and Down Syndrome

1. Intellectual
Disabilities

2. What Causes Intellectual Disabilities?
 There's a problem with the baby's genes, which are in every
cell and determine how the body will develop. (a baby
might receive genes that are abnormal or the genes might
change while the baby is developing.)
 There's a problem during the pregnancy. Sometimes, the
mother might get an illness or infection that can harm the
baby. Taking certain medicines while pregnant can cause
problems for the baby. Drinking alcohol or taking illegal
drugs can also damage a baby's developing brain.
 During childbirth, if the baby doesn't get enough oxygen.
 Premature birth.
 After birth, the baby gets a serious brain infection.
 Any time in life, a serious head injury can hurt the brain
and cause intellectual disabilities. Some of these
disabilities are temporary and others can be permanent.

3. Mental Retardation
 A term that was once commonly used to describe
someone who learns and develops more slowly than
others.
 Someone who has this kind of problem will have
trouble learning and functioning in everyday life. This
person could be 10 years old, but might not talk or
write as well as a typical 10-year-old. He or she is also
usually slower to learn other skills, like how to get
dressed or how to act around other people.

4. Characteristics of Children with
Mental Retardation
 Many children with mild retardation are not identified
until they enter school and sometimes not until the
standard 1 or 2 level, when more difficult academic
work is required. Most students with mild mental
retardation master academic skills up to about the
form 4 or 5 level and are able to learn job skills well
enough to support themselves independently or semi-
independently. Some adults who have been identified
with mild mental retardation develop excellent social
and communication skills and once they leave school
are no longer recognized as having a disability.

5. Characteristics of Children with
Mental Retardation
 Children with moderate retardation show significant
delays in development during their preschool years. As
they grow older, discrepancies in overall intellectual
development and adaptive functioning generally grow
wider between these children and children their ages
without disabilities. People with moderate mental
retardation are more likely to have health and behavior
problems than are individuals with mild retardation.

6. Characteristics of Children with
Mental Retardation
 Individuals with severe and profound mental
retardation are almost always identified at birth or
shortly afterward. Most of these infants have
significant central nervous system damage, and many
have additional disabilities and/or health conditions.
Although IQ scores can serve as the basis for
differentiating severe and profound retardation from
one another, the difference is primarily one of
functional impairment.

7. Cognitive Functioning
 Deficits in cognitive functioning and learning styles
characteristic of individuals with mental retardation
include poor memory, slow learning rates, attention
problems, difficulty generalizing what they have
learned, and lack of motivation.

8. Memory
 Students with mental retardation have difficulty remembering information. As
would be expected, the more severe the cognitive impairment, the greater the
deficits in memory. In particular, research has found that students with mental
retardation have trouble retaining information in short-term memory
(Bray, Fletcher, & Turner, 1997). Short-term memory, or working memory, is the
ability to recall and use information that was encountered just a few seconds to
a couple of hours earlier—for example, remembering a specific sequence of job
tasks an employer stated just a few minutes earlier. Merrill (1990) reports that
students with mental retardation require more time than their nondisabled
peers to automatically recall information and therefore have more difficulty
handling larger amounts of cognitive information at one time. Early
researchers suggested that once persons with mental retardation learned a
specific item of information sufficiently to commit it to long-term memory—
information recalled after a period of days or weeks—they retained that
information about as well as persons without retardation (Belmont, 1966;
Ellis, 1963

9. Memory Continued
 More recent research on memory abilities of persons
with mental retardation has focused on teaching
metacognitive or executive control strategies, such as
rehearsing and organizing information into related
sets, which many children without disabilities learn to
do naturally (Bebko & Luhaorg, 1998). Students with
mental retardation do not tend to use such strategies
spontaneously but can be taught to do so with
improved performance on memory-related and
problem-solving tasks as an outcome of such strategy
instruction (Hughes & Rusch, 1989; Merrill, 1990).

10. Learning Rate
 The rate at which individuals with mental retardation
acquire new knowledge and skills is well below that of
typically developing children. A frequently used
measure of learning rate is trials to criterion—the
number of practice or instructional trials needed
before a student can respond correctly without
prompts or assistance. For example, while just 2 or 3
trials with feedback may be required for a typically
developing child to learn to discriminate between two
geometric forms, a child with mental retardation may
need 20 to 30 or more trials to learn the same
discrimination.

11. Learning Rate Continued
 Because students with mental retardation learn more
slowly, some educators have assumed that instruction
should be slowed down to match their lower rate of
learning. Research has shown, however, that students
with mental retardation benefit from opportunities to
learn to “go fast” (Miller, Hall, & Heward, 1995).

12. Attention
 The ability to attend to critical features of a task (e.g., to
the outline of geometric shapes instead of dimensions such
as their color or position on the page) is a characteristic of
efficient learners. Students with mental retardation often
have trouble attending to relevant features of a learning
task and instead may focus on distracting irrelevant
stimuli. In addition, individuals with mental retardation
often have difficulty sustaining attention to learning tasks
(Zeaman & House, 1979). These attention problems
compound and contribute to a student’s difficulties in
acquiring, remembering, and generalizing new knowledge
and skills.

13. Attention Continued
 Effective instructional design for students with mental
retardation must systematically control for the
presence and saliency of critical stimulus dimensions
as well as the presence and effects of distracting
stimuli. After initially directing a student’s attention to
the most relevant feature of a simplified task and
reinforcing correct responses, the complexity and
difficulty of the task can gradually be increased. A
student’s selective and sustained attention to relevant
stimuli will improve as he experiences success for
doing so.

14. Generalization of Learning
 Students with disabilities, especially those with mental
retardation, often have trouble using their new knowledge and
skills in settings or situations that differ from the context in
which they first learned those skills. Such transfer or
generalization of learning occurs without explicit programming
for many children without disabilities but may not be evident in
students with mental retardation without specific programming
to facilitate it. Researchers and educators are no longer satisfied
by demonstrations that individuals with mental retardation can
initially acquire new knowledge or skills. One of the most
important and challenging areas of contemporary research in
special education is the search for strategies and tactics for
promoting the generalization and maintenance of learning by
individuals with mental retardation. Some of the findings of that
research are described later in this chapter and throughout this
text.

15. Motivation
 Some students with mental retardation exhibit an apparent
lack of interest in learning or problem-solving tasks
(Switzky, 1997). Some individuals with mental retardation
develop learned helplessness, a condition in which a
person who has experienced repeated failure comes to
expect failure regardless of his or her efforts. In an attempt
to minimize or offset failure, the person may set extremely
low expectations for himself and not appear to try very
hard. When faced with a difficult task or problem, some
individuals with mental retardation may quickly give up
and turn to or wait for others to help them. Some acquire a
problem-solving approach called outer-directedness, in
which they seem to distrust their own responses to
situations and rely on others for assistance and solutions.

16. Motivation Continued
 Rather than an inherent characteristic of mental
retardation, the apparent lack of motivation may be the
product of frequent failure and prompt dependency
acquired as the result of other people’s doing things for
them. After successful experiences, individuals with mental
retardation do not differ from persons without mental
retardation on measures of outer-directedness (Bybee &
Zigler, 1998). The current emphasis on teaching self-
determination skills to students with mental retardation is
critical in helping them to become self-reliant problem
solvers who act upon their world rather than passively wait
to be acted upon (Wehmeyer, Martin, & Sands, 1998).

17. Self-Care and Daily Living Skills
 Individuals with mental retardation who require
extensive supports must often be taught basic self-care
skills such as dressing, eating, and hygiene. Direct
instruction and environmental supports such as added
prompts and simplified routines are necessary to
ensure that deficits in these adaptive areas do not
come to seriously limit one’s quality of life. Most
children with milder forms of mental retardation learn
how to take care of their basic needs, but they often
require training in self-management skills to achieve
the levels of performance necessary for eventual
independent living.

18. Social Development
 Making and sustaining friendships and personal
relationships present significant challenges for many
persons with mental retardation. Limited cognitive
processing skills, poor language development, and unusual
or inappropriate behaviors can seriously impede
interacting with others. It is difficult at best for someone
who is not a professional educator or staff person to want
to spend the time necessary to get to know a person who
stands too close, interrupts frequently, does not maintain
eye contact, and strays from the conversational topic.
Teaching students with mental retardation appropriate
social and interpersonal skills is one of the most important
functions of special education.

19. Behavioral Excesses and
Challenging Behavior
 Students with mental retardation are more likely to exhibit behavior
problems than are children without disabilities. Difficulties accepting
criticism, limited self-control, and bizarre and inappropriate behaviors
such as aggression or self-injury are often observed in children with
mental retardation. Some of the genetic syndromes associated with
mental retardation tend to include abnormal behavior (e.g., children
with Prader-Willi syndrome often engage in self-injurious or obsessive-
compulsive behavior). In general, the more severe the retardation, the
higher the incidence of behavior problems. Individuals with mental
retardation and psychiatric conditions requiring mental health
supports are known as “dual diagnosis” cases. Data from one report
showed that approximately 10% of all persons with mental retardation
served by the state of California were dually diagnosed (Borthwick-
Duffy & Eyman, 1990). Although there are comprehensive guidelines
available for treating psychiatric and behavioral problems of persons
with mental retardation (Rush & Francis, 2000), much more research is
needed on how best to support this population.

20. Positive Attributes
 Descriptions of the intellectual functioning and
adaptive behavior of individuals with mental
retardation focus on limitations and deficits and paint
a picture of a monolithic group of people whose most
important characteristics revolve around the absence
of desirable traits. But individuals with mental
retardation are a huge and disparate group composed
of people with highly individual personalities (Smith &
Mitchell, 2001b). Many children and adults with
mental retardation display tenacity and curiosity in
learning, get along well with others, and are positive
influences on those around them (Reiss & Reiss, 2004;
Smith, 2000).

21. Down Syndrome
 Down syndrome (DS), also called Trisomy 21, is a condition
in which extra genetic material causes delays in the way a
child develops, both mentally and physically.
 The physical features and medical problems associated
with Down syndrome can vary widely from child to child.
While some kids with DS need a lot of medical
attention, others lead healthy lives.
 Though Down syndrome can't be prevented, it can be
detected before a child is born. The health problems that
may go along with DS can be treated, and many resources
are available to help kids and their families who are living
with the condition.

22. What Causes It?
 Normally, at the time of conception a baby inherits genetic
information from its parents in the form of 46
chromosomes: 23 from the mother and 23 from the father.
In most cases of Down syndrome, a child gets an extra
chromosome 21 — for a total of 47 chromosomes instead of
46. It's this extra genetic material that causes the physical
features and developmental delays associated with DS.
 Although no one knows for sure why DS occurs and there's
no way to prevent the chromosomal error that causes
it, scientists do know that women age 35 and older have a
significantly higher risk of having a child with the
condition. At age 30, for example, a woman has about a 1 in
1,000 chance of conceiving a child with DS. Those odds
increase to about 1 in 400 by age 35. By 40 the risk rises to
about 1 in 100.

23. Physical Features of Persons with
Down Sydrome
 Kids with Down syndrome tend to share certain
physical features such as a flat facial profile, an upward
slant to the eyes, small ears, and a protruding tongue.

24. How Down Syndrome Affects Kids
 Low muscle tone (called hypotonia) is also characteristic of children
with DS, and babies in particular may seem especially "floppy." Though
this can and often does improve over time, most children with DS
typically reach developmental milestones — like sitting
up, crawling, and walking — later than other kids.
 At birth, kids with DS are usually of average size, but they tend to grow
at a slower rate and remain smaller than their peers. For infants, low
muscle tone may contribute to sucking and feeding problems, as well
as constipation and other digestive issues. Toddlers and older kids may
have delays in speech and self-care skills like feeding, dressing, and
toilet teaching.
 Down syndrome affects kids' ability to learn in different ways, but most
have mild to moderate intellectual impairment. Kids with DS can and
do learn, and are capable of developing skills throughout their lives.
They simply reach goals at a different pace — which is why it's
important not to compare a child with DS against typically developing
siblings or even other children with the condition.

25. Medical Problems Associated With DS
 While some kids with DS have no significant health
problems, others may experience a host of medical issues
that require extra care. For example, almost half of all
children born with DS will have a congenital heart defect.
 Kids with Down syndrome are also at an increased risk of
developing pulmonary hypertension, a serious condition
that can lead to irreversible damage to the lungs. All
infants with Down syndrome should be evaluated by a
pediatric cardiologist.
 Approximately half of all kids with DS also have problems
with hearing and vision. Hearing loss can be related to
fluid buildup in the inner ear or to structural problems of
the ear itself. Vision problems commonly include
strabismus (cross-eyed), near- or farsightedness, and an
increased risk of cataracts.

26. Medical Problems Associated With DS
 Regular evaluations by an otolaryngologist (ear, nose, and
throat doctor), audiologist, and an ophthalmologist are
necessary to detect and correct any problems before they
affect language and learning skills.
 Other medical conditions that may occur more frequently
in kids with DS include thyroid problems, intestinal
abnormalities, seizure disorders, respiratory
problems, obesity, an increased susceptibility to
infection, and a higher risk of childhood leukemia. Upper
neck abnormalities are sometimes found and should be
evaluated by a doctor (these can be detected by cervical
spine X-rays). Fortunately, many of these conditions are
treatable.

27. Prenatal Screening and Diagnosis
 Two types of prenatal tests are used to detect Down
syndrome in a fetus: screening tests and diagnostic tests.
Screening tests estimate the risk that a fetus has DS;
diagnostic tests can tell whether the fetus actually has the
condition.
 Screening tests are cost-effective and easy to perform. But
because they can't give a definitive answer as to whether a
baby has DS, these tests are used to help parents decide
whether to have more diagnostic tests.
 Diagnostic tests are about 99% accurate in detecting Down
syndrome and other chromosomal abnormalities. However,
because they're performed inside the uterus, they are
associated with a risk of miscarriage and other
complications.

28. Prenatal Screening and Diagnosis
 For this reason, invasive diagnostic testing previously was
generally recommended only for women age 35 or
older, those with a family history of genetic defects, or
those who've had an abnormal result on a screening test.
 However, the American College of Obstetrics and
Gynecology (ACOG) now recommends that all pregnant
women be offered screening with the option for invasive
diagnostic testing for Down syndrome, regardless of age.
 If you're unsure about which test, if any, is right for
you, your doctor or a genetic counselor can help you sort
through the pros and cons of each.

29. Nuchal translucency testing
 This test, performed between 11 and 14 weeks of
pregnancy, uses ultrasound to measure the clear space
in the folds of tissue behind a developing baby's neck.
(Babies with DS and other chromosomal abnormalities
tend to accumulate fluid there, making the space
appear larger.) This measurement, taken together with
the mother's age and the baby's gestational age, can be
used to calculate the odds that the baby has DS.
Nuchal translucency testing is usually performed
along with a maternal blood test.

30. The triple screen or quadruple
screen (also called the multiple marker
test)
 These tests measure the quantities of normal
substances in the mother's blood. As the names
imply, triple screen tests for three markers; the
quadruple screen includes one additional marker and
is more accurate. These tests are typically offered
between 15 and 18 weeks of pregnancy.

31. Integrated screen
 This uses results from first-trimester screening tests
(with or without nuchal translucency) and blood tests
with a second trimester quadruple screen to come up
with the most accurate screening results.

32. A genetic ultrasound
 A detailed ultrasound is often performed at 18 to 20
weeks in conjunction with the blood tests, and it
checks the fetus for some of the physical traits
abnormalities associated with Down syndrome.

33. Diagnostic tests include:
 Chorionic villus sampling (CVS). CVS involves taking a tiny
sample of the placenta, either through the cervix or through a
needle inserted in the abdomen. The advantage of this test is
that it can be performed during the first trimester, typically
between 10 and 12 weeks. The disadvantage is that it carries a
slightly greater risk of miscarriage as compared with
amniocentesis and has other complications.
 Amniocentesis. This test, performed between 15 and 20 weeks
of pregnancy, involves the removal of a small amount of amniotic
fluid through a needle inserted in the abdomen. The cells can
then be analyzed for the presence of chromosomal
abnormalities. Amniocentesis carries a small risk of
complications, such as preterm labor and miscarriage.
 Percutaneous umbilical blood sampling (PUBS). Usually
performed after 18 weeks, this test uses a needle to retrieve a
small sample of blood from the umbilical cord. It carries risks
similar to those associated with amniocentesis.

34. Resources That Can Help
 If you're the parent of a child diagnosed with Down
syndrome, talking with other parents of kids with DS may
help you deal with the initial shock and grief and find ways
to look toward the future. Many parents find that learning
as much as they can about DS helps ease some of their
fears.
 Experts recommend enrolling kids with Down syndrome in
early-intervention services as soon as possible. Physical,
occupational, and speech therapists and early-childhood
educators can work with your child to encourage and
accelerate development.
 Many states provide free early-intervention services to kids
with disabilities from birth to age 3, so check with your
doctor or a social worker to learn what resources are
available in your area.

35. Resources That Can Help
 Once your child is 3 years old, he or she is guaranteed educational
services under the Individuals with Disabilities Education Act (IDEA).
Under IDEA, local school districts must provide "a free appropriate
education in the least restrictive environment" and an individualized
education plan (IEP) for each child.
 Where to send your child to school can be a difficult decision. Some
kids with Down syndrome have needs that are best met in a specialized
program, while many others do well attending neighborhood schools
alongside peers who don't have DS. Studies have shown that this type
of situation, known as inclusion, is beneficial for both the child with
DS as well as the other kids.
 Your school district's child study team can work with you to determine
what's best for your child, but remember, any decisions can and should
involve your input, as you are your child's best advocate.
 Today, many kids with Down syndrome go to school and enjoy many of
the same activities as other kids their age. A few go on to college. Many
transition to semi-independent living. Still others continue to live at
home but are able to hold jobs, thus finding their own success in the
community.

36. Down Syndrome (Adult) Down Syndrome (Baby)