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Mental Retardation

Legal Definition

According to the Persons with Disabilities Act, 1995; mental retardation is defined as "a condition of arrested or incomplete development of the mind which is specially characterized by sub normality of intelligence."

Other Definitions

Mental retardation is defined as "a significantly sub-average level of intellectual functioning associated with deficits in adaptive behavior and manifests itself during the developmental period." (Grossman, 1972).

Causes of Mental Retardation

There are more than 250 identified causes of mental retardation, but in approximately one third of the people with mental retardation, the cause is unkown. From the numerous factors associated with mental retardation, the American Association on Mental Retardation (AAMR) has categorized mental retardation into prenatal (occurring before birth), perinatal (occurring during or shortly after birth) or postnatal causes.

Mental retardation can occur due to the following prenatal causes:

  • chromosomal disorders such as Down syndrome, Fragile-X syndrome, Turner’s syndrome, Klinefelter syndrome
  • developmental disorders of brain formation such as spina bifida, hydrocephalus, and microcephalus

Perinatal causes such as:

  • intrauterine disorders such as premature delivery, abnormal presentation, umbilical cord accidents
  • neonatal disorders such as neonatal seizures, meningitis, head trauma at birth
  • birth asphyxia or lack of oxygen at birth

Postnatal causes such as:

  • head injuries
  • infections such as encephalitis, meningitis, malaria, measles, rubella
  • seizure disorders such as epilepsy
  • degenerative disorders such as Rett syndrome
  • diet deficiencies

Source: Exceptional Children An introduction to special education, 7th edition, Heward, W. L., Merril Prentice Hall.

Teaching Children with Mental Retardation

Research indicates that early identification and intensive education of children with mental retardation shows promise. Here are some tips:

  • Use age appropriate and interesting materials when teaching.
  • Provide step-by-step directions with verbal instructions as well as opportunities for hand-on learning.
  • Break down activities into smaller components (task analyses). For example, the activity of brushing one’s teeth should be broken down into smaller components.
  • Positively reinforce (praise) desired behavior and give consistent feedback.
  • Teach in the actual setting where the student will use the new skill.
  • Teach functional skills such as how to write a cheque, how to access leisure activities in the community. For example, teach how to book movie tickets at the local theatre.

Source: Exceptional Children An introduction to special education, 7th edition, Heward, W. L., Merril Prentice Hall.

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