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Unit 14: Identification: Causes, Problems of Mentally Retarted

1. Heredity-Endo-genous factors : may be of the following types– Notes
(a) Development defects : before birth, skull deformities and endocrine disorders.
(b) Metabolic defects : skin diseases, infantile juvenile.
(c) Neuromotor defect : motor skills defects, motor paralysis
(d) Psychological disorder : Sensory’ defects, psychic defects.
2. Environment-Exogenous factors : these may be of the following types–
(a) Developments after the birth of the child.
(b) Anti-measures used by mother in pregnancy.
(c) Post natal conditions-direct injury, disease etc.
(d) Process of Growth and development- 1. Developmental defects, 2. Metabolic defects. 3.
Meurosomotor defects, and 4. Psychological disorder.
Kirk has enumerated the causes of retardation into three categories- (1) Organic or biological,
(2) Genetic or heredity and (3) Cultural or environmental factors. The empirical research studies
have yielded that three types of factors are responsible for the mental retardation of children.
Mental Retardation occurs due to genetic and environmental factors which come into play at
pre-natal, perinatal and postnatal stages of development.

Mentally retarded children are identified by using both observation of their behaviours
and administering intelligence test to ascertain their level of intelligence.

(1) Heredity-Endo-genous Causes of MR
One of the most visible conditions associated with mental retardation of Down’s Syndrome.
Down’s Syndrome contains the non-sex determining chromosome. Chromosomal anomaly
explains many forms of mental disorders. In non-dysjunction Down’s Syndrom one pair of
genes faild to separate at conception, resulting in an extra or 47th chromosome after forty-six
known as Tirsomy-21. The face of the child has palpebral fissures that are oblique and narrow
laterally, specked iris, flatness of the nose bridge, enlarged tongue, small ears, and short and
broad neck. Other common anomalies are flattening of the occiput, broad hands with the little
finger curved, short broad feet with a wide space between the first and second toes, pelvic
anomalies, and congenital heart anomalies in almost 25 of patients. Intellectual development is
impaired.
There is clear cut association between Mental Age and Trisomy - 21
Down’s Syndrom Below 20 20-24 25-29 30-34 35-39 40+
Incidence per 1000 0.46 0.65 0.88 1.26 3.92 17.60
Whatever the IQ value, it seems safe to say that Trisomy-21 children will not be able to enjoy an
independent life, even if some of them reach borderline intelligence. Mongolism or Down’s
Syndrome is due to the presence of three types of chromosomal anomalies. Three main
cytogenetic forms are known : with 47 chromosome and a standard trisomy-21 (95% of all
case): with normal mosaics, with 46 chromosomes/trisomy-21 (two three percent), and with
translocations (two to three percent). Although it is not known that the causes are a close
association between maternal age and trisomy 21 has been repeatedly demonstrated.
These children need extra care. Parental support is a vital need to ensure that infant stimulation
programmes emphasizing self-help skills, language acquisition, feeding, toilet training, and
positive socialization, are provided. Down’s syndrome individuals are educable and should
have exposure to their non-handicapped peers from their early years. In the past, professionals
advised parents lo place their Down’s syndrome child in 24-hour institutional care based on

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