What Causes Intellectual Disabilities? Theres a problem with the babys 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.) Theres 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 babys developing brain. During childbirth, if the baby doesnt 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.
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.
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.
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.
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.
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.
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
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).
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.
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).
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.
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.
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.
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.
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).
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.
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.
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.
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).
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 cant 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.
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. Its 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 theres 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.
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.
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 its important not to compare a child with DS against typically developing siblings or even other children with the condition.
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.
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.
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 cant 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 theyre performed inside the uterus, they are associated with a risk of miscarriage and other complications.
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 whove 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 youre 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.
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 babys neck. (Babies with DS and other chromosomal abnormalities tend to accumulate fluid there, making the space appear larger.) This measurement, taken together with the mothers age and the babys 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.
The triple screen or quadruple screen (also called the multiple marker test) These tests measure the quantities of normal substances in the mothers 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.
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.
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.
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.
Resources That Can Help If youre 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.
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 dont 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 districts child study team can work with you to determine whats best for your child, but remember, any decisions can and should involve your input, as you are your childs 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.