Mental retardation (MR) has been defined as below average general intellectual functioning with associated deficits in adaptive behaviour that occurs before the age of 18 years. It is classified on the basis of the individual's IQ level:
Profound MR -> IQ = 0-24
Severe MR -> IQ = 25-40
Moderate MR -> IQ = 40-54
Mild MR -> IQ = 55-69
Borderline MR -> IQ = 70-84
IQ is a measure of intellectual functioning as it measures an individual's mental age against his actual chronological age. IQ = mental age/chronological age multiplied by 100. It is a ratio of the child's mental age relative to his birth age in years.
Though IQ is taken as the main indicator of mental retardation, there have to be serious limitations in the way a child adjusts to the social environment, for him to be diagnosed as intellectually impaired. Mental retardation is now variously referred to as cognitive (mental) deficit and intellectual impairment.
What are the causes?
Intellectual impairment is more an effect rather than the cause of a condition. There are many conditions in children that are associated with deficits in intellectual functioning. Some of the common causes are:
Genetic conditions – some genetic or chromosomal abnormalities like Down's syndrome, fragile X syndrome, Klinefelter's syndrome, phenylketonuria, cri-du-chat syndrome are some of the disorders in which the child is intellectually impaired.
Problems during birth – there may be damage to the child's brain during childbirth which may cause impairment of intellectual functioning. Premature babies and those born with a low birth weight are more susceptible than full term infants. The brain may be affected if the child has been deprived of oxygen during birth.
Childhood diseases – many diseases that the child may contract during childhood may affect brain functioning. Diseases like meningitis, high fevers, epilepsy, encephalitis etc. may cause retardation. Autism is most often associated with some degree of mental retardation.
During pregnancy, excessive intake of alcohol by the mother, smoking or diseases like rubella and syphilis predispose the child to intellectual impairment.
Cultural deprivation – children from poor families or those that have been raised in relative isolation are more prone to have deficits in functioning. Also children who have had difficult childhoods develop mental disorders which may be associated with mental retardation. Under stimulation of intellect during childhood may be another cause.
What are the symptoms?
The symptoms for intellectual retardation are not well defined since they vary with the severity of the condition. Children with mild intellectual deficits are generally not spotted till they begin school. The most common indicator of impaired mental functioning is the child's underperformance at school. The child may show behaviour not appropriate for his age, may have a decreased learning ability and may not be curious about things around him.
Children with severe forms of intellectual disability may have trouble taking care of their daily needs and may require adult help. Almost all children with mental deficits show delayed developmental milestones, in that they sit and stand later than normal children and may also acquire speech later.
How is it diagnosed?
Intellectual impairment is suspected in children who show delayed development of milestones. The paediatrician may conduct a few tests to rule out any organic cause for the developmental delay. The child may then be referred to a child psychologist who will administer specialised tests to diagnose the retardation. The child's IQ is measured and some other tests for motor functioning confirm the diagnosis.
What is the treatment?
There is no medical treatment for intellectual impairment since it is not a disease condition. Treatment strategy involves rehabilitation of the child and making him acquire adaptive skills for everyday life. Special schools provide individualised education to these children, so that they are able to acquire knowledge at their own pace. Apart from academic knowledge, special education also provides these children with the requisite skills so that they are able to adjust in society.
Specific treatment measures like behaviour therapy are used to reduce socially unacceptable behaviour of these children. For example, children with intellectual impairment may have a very low attention span and thus may disrupt their surroundings. Therapy helps to reduce such behaviour.
Integrated education is a common approach being applied in case of intellectual impairment in recent times. In this approach, cognitively deficient children are taught with non-disabled children in normal classrooms, but, some skills are imparted to them separately. This helps to give these children the best of both worlds.
Children with intellectual impairment are different from their peers in that they need more individual attention than other children. However, they need as much love and support as other children do. With early intervention, most children are able to live efficient and satisfactory lives.