Mental retardation

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. As many as 3 out of every 100 people have mental retardation. In fact, 1 out of every 10 children who need special education has some form of mental retardation. There are many causes of mental retardation. The most common causes are: {{}}Genetic conditions — Abnormalities of chromosomes and genes. Examples of genetic conditions are Down syndrome (trisomy 21), fragile X syndrome, and phenylketonuria (PKU). Problems during pregnancy — When the baby does not develop normally inside the mother. For example, a woman who drinks alcohol or gets an infection like rubella during pregnancy may have a baby with mental retardation. Perinatal problems — Problems during labor and birth, such as not getting enough oxygen. Health problems — Diseases like whooping cough, the measles, or meningitis. Mental retardation can also be caused by extreme malnutrition or being exposed to poisons like lead or mercury. The diagnosis of mental retardation is made by looking at two main things. These are (1) the ability of a person's brain to learn, think, solve problems, and make sense of the world (intellectual functioning or IQ); and (2) whether the person has the skills he or she needs to live independently (called adaptive behavior, or adaptive functioning). Intellectual functioning, or IQ, is usually measured by an IQ test. The average IQ score is, by definition, 100. People scoring below 70 to 75 on the IQ test are considered to have mental retardation. To measure adaptive behavior, professionals look at what a child can do in comparison to other children of his or her age. Certain skills are important to adaptive behavior. These are daily living skills (such as getting dressed, going to the bathroom, and feeding one's self), communication skills (such as understanding what is said and being able to answer) and social skills (interacting with peers, family members, adults, and others).

* * *

mental retardation n subaverage intellectual ability equivalent to or less than an IQ of 70 that is accompanied by significant deficits in abilities (as in communication or self-care) necessary for independent daily living, is present from birth or infancy, and is manifested esp. by delayed or abnormal development, by learning difficulties, and by problems in social adjustment

mentally retarded adj

* * *

the state of those whose intellectual powers have failed to develop to such an extent that they are in need of care and protection and require special education. It is also known as mental deficiency and mental handicap. The handicap may be classified according to the intelligence quotient (IQ) as mild (IQ 50-70), moderate to severe (IQ 20-50), and profound (IQ less than 20). Mildly handicapped people often make a good adjustment to life after special help with education. The moderately and severely handicapped usually need much more help and most are permanently dependent on other people, while the profoundly handicapped usually need constant attention. There are very many causes of mental retardation, including Down's syndrome, inherited metabolic disorders, brain injury, and gross psychological deprivation; some are preventable or treatable.

* * *

[DSM-IV] a mental disorder characterized by significantly subaverage general intellectual functioning associated with impairments in adaptive behavior and manifested during the developmental period. It is classified on the basis of severity as mild, moderate, severe, and profound; a fifth subgroup, borderline intellectual functioning, is sometimes included.