Approximately 85% of the mentally retarded population falls under this category. Their IQ score ranges from 50–70, and they can often acquire academic skills up to about the sixth-grade level. They can become fairly self-sufficient and in some cases live independently, with community and social support. (Mental retardation)
MODERATE MENTAL RETARDATION
About 10% of the mentally retarded population is considered moderately retarded. Moderately retarded persons have IQ scores ranging from 35–55. They can often lead relatively normal lives and can carry out work and self-care tasks with moderate supervision. They typically acquire communication skills in childhood and are able to live and function successfully within the community in such supervised environments as group homes with other mentally retarded people. (Mental retardation)
SEVERE MENTAL RETARDATION
About 3–4% of the mentally retarded population is severely retarded. They have IQ scores of 20–40 and may master very basic self-care skills (Mental retardation) such as cleaning and dressing themselves (MENTAL RETARDATION) and some communication skills. They often live in group homes.
PROFOUND MENTAL RETARDATION
Only 1–2% of the mentally retarded population is classified as profoundly retarded; having IQ scores under 20–25. They may be able to develop basic self-care and communication skills with appropriate support and training. Their retardation is often caused by an accompanying neurological disorder. Profoundly retarded people need a high level of structure and supervision (Mental retardation).
CAUSES
Anything that damages and interferes with the growth and maturation of the brain can lead to mental retardation. This might happen before, during or after the birth of the child. Mental retardation affects about 1 - 3% of the population (Rachel, 2007). There are many causes of mental retardation, but in about one-third of all cases, the cause of mental retardation is not known. The remaining two-thirds of cases are thought to be caused by one of four factors (MENTAL RETARDATION):
- Genetic
- Prenatal illnesses and issues
- Childhood illnesses and injuries
- Environmental factors
GENETIC FACTORS
About 5 / 30% percent of mental retardation cases are caused by genetic factors (MENTAL RETARDATION). Abnormalities of genes inherited from parents, errors when genes combine, or from other disorders of the genes caused during pregnancy by infections, overexposure to x-rays and other factors interfere with the normal development of the child's brain leading to mental retardation. There are many genetic diseases associated with mental retardation. Some examples include PKU (phenylketonuria) and Fragile X syndrome - single gene disorders caused due to a missing or defective enzyme and disorder located on the X chromosome, respectively. Down syndrome is an example of a chromosomal disorder caused by an extra chromosome 21(Causes and Prevention of Mental Retardation).
PRENATAL ILLNESSES AND ISSUES
The daily choices a pregnant woman makes may affect the mental health of her fetus. For example, fetal alcohol syndrome (FAS) caused by excessive drinking by the mother during pregnancy, drug abuse and smoking during pregnancy may also cause mental retardation in the fetus. Infections in the mother may also lead to mental retardation of the fetus. The infections may spread to the fetus and damage its nervous system, including its brain. High blood pressure and blood poisoning in a pregnant woman reduces the flow of oxygen to the fetus causing brain damage (MENTAL RETARDATION).
Other risks like certain environmental toxins during pregnancy and difficulties in the birth process such as temporary oxygen deprivation or birth injuries may cause mental retardation (Causes and Prevention of Mental Retardation). A balanced diet rich in calories, protein, vitamins, minerals and iodine is required for pregnant women. Lack of adequate diet can have direct and indirect effects on brain development and thereby increase the risk of subnormal development (What causes Mental Retardation?).
CHILDHOOD ILLNESSES AND INJURIES
Children sometimes experience serious infections like meningitis - infection of the membrane covering the brain and encephalitis - inflammation of the brain can cause swelling in turn may damage brain cells and bring about retardation (MENTAL RETARDATION). Traumatic brain injuries caused by a blow to the head, near drowning or a violent shaking of the upper body by an adult may cause brain damage and mental retardation in children. Childhood illnesses like Hyperthyroidism, whooping cough, chickenpox, measles, and Hib disease may also cause mental retardation if they are not treated adequately (Mental retardation). Children, when they recover from acute illness, are noticed to have lost many skills which they had learnt earlier (What causes Mental Retardation?).
ENVIRONMENTAL FACTORS
Children who might otherwise develop normally sometimes become mentally retarded because of the environment in which they live. Poverty, malnutrition, unhealthy living conditions, and inadequate medical care may all increase a child's risk for mental retardation (MENTAL RETARDATION). Ignored or abused infants who are not provided with the mental and physical stimulation required for normal development may suffer irreversible learning impairment. Exposure to lead or mercury can also cause mental retardation. Many children have developed lead poisoning from eating the flaking lead-based paint often found in older buildings (Mental retardation).
Parents should not loose hope and temper easily as it takes longer for children who are mentally retarded to reach developmental milestones significantly later than expected or learning and adaptive skills that were once easy may suddenly become difficult to master due to injuries. These children need supervision from their parents and the people around them; who need to be very patient and careful in providing the special attention they require.
REFERENCES:
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Rachel A. Lewis (2007), In Medical Encyclopedia, Retrieved 14th April, 2009 from the website http://www.nlm.nih.gov/medlineplus/ency/article/001523.htm
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Causes and Prevention of Mental Retardation (n.d) Retrieved 14th April, 2009 from the website http://www.thearc.org/ NetCommunity/Document.Doc?&id=147
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Causes and Prevention of Mental Retardation (n.d), Retrieved 14th April, 2009 from the website http://hubpages.com/hub/Causes-and-Prevention-of-Mental-Retardation
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Stephen Brian Sulkes, (2006) Mental Retardation/Intellectual Disability Retrieved 14th April, 2009 from the website http://www.merck.com/mmhe/sec23/ch285/ch285a.html
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Mental Retardation - Causes Of Mental Retardation (n.d) Retrieved 14th April, 2009 from the website http://social.jrank.org/pages/407/Mental-Retardation.html
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Mental retardation (n.d), In Encyclopedia of Mental Disorders Retrieved 14th April, 2009 from the website http://www.minddisorders.com/Kau-Nu/Mental-retardation.html
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MENTAL RETARDATION (n.d), In Free Health Encyclopedia Retrieved 14th April, 2009 from the website http://www.faqs.org/health/Sick-V3/Mental-Retardation.html
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What causes Mental Retardation? (n.d) Retrieved 14th April, 2009 from the website http://www.searo.who.int/en/Section1174/Section1199/Section1567/Section1825_8090.htm
