Mental Retardation

What is Mental Retardation?
According to World Health Organisation [WHO] Mental Retardation [M.R] is a condition in which there is delay or deficiency in all aspects of development, i.e. there is global and noticeable deficiency in the development of motor, cognitive, social, and language functions. This is the commonest form of developmental disability.
Mental retardation is always diagnosed before age 18 and includes below-average general intellectual function, and a lack of the skills necessary for daily living.
Generally, mental retardation is a life-long condition. Those affected continue to have diminished intellectual capacity throughout their lives. However, in most individuals with mental retardation, those parts of the brain that are not damaged continue to develop. Therefore, they continue to acquire skills and abilities as they grow older, albeit slowly.
Mental retardation is not the same as mental illness. The major characteristic of mental retardation is delay in mental development, whereas the major characteristic of mental illness is disturbance in the mental functions of thinking, feeling, and behaviour. Mental illness can occur at any age, whereas mental retardation is present from childhood. However, some people with mental retardation may also develop mental illness.
Adaptive behaviour is always impaired, but in protected social environments where support is available this impairment may not be at all obvious in subjects with mild mental retardation.
Causes of Mental Retardation:
A. Prenatal: causes that occur before birth:
Chromosomal disorders like Fragile X syndrome, single gene disorders like Inborn errors of metabolism such as galactosemia, phenylketonuria, , Tay- Sachs disease , Adverse material / environmental influences like environmental stress, Deficiencies, such as iodine deficiency and folic acid deficiency
B. Perinatal: causes that occur during the birth process:
Placental dysfunction, severe prematurity, very low birth weight, birth asphyxia, birth trauma, complicated delievery,neonatal conditions like septicaemia,severe jaundice or hypoglycemia
C. Postnatal: causes that happen after birth or during childhood:
Brain infections such as tuberculosis, Japanese encephalitis and bacterial meningitis, head injury, chronic lead exposure, severe and prolonged malnutrition and gross under stimulation.
D. Genetic conditions: These result from 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.
When should a couple consider genetic counseling?
Genetic counseling should be considered if:

  • the child may inherit a genetic or chromosomal disorder because of a specific condition in the family;
  • a previous birth to either parent resulted in a child with a genetic disorder, unexplained mental retardation or a birth defect;
  • the partners are blood relatives.
  • the mother has had two or more miscarriages or a baby who died in infancy;
  • either partner is of a race or ethnic group with a high incidence of a genetic condition; and
  • the mother is 35 years of age or over;

Types of Mental Retardation:
• Degrees of mental retardation
Not all people with mental retardation have the same level of intelligence. The scientific method of measuring intelligence is through standardized psychological tests called IQ tests. IQ or intelligence quotient, is the percentage of intelligence a person has, in comparison to a normal person from a similar background. Based on IQ, mental retardation can be classified into different degrees as follows [ICD-10]:
Category Intelligence Quotient [I.Q]
Average 90-110
Borderline 70-89
Mild 50-69
Moderate 35-49
Severe 20- 34
Profound Under 20

Other types of Mental Retardation:

  • Down’s Syndrome (Mongolism)
  • Phenylkketonuria (PKU)
  • Cranial Anomalies
  • Cretinism (Thyroid Deficiency)
  • Microcephaly
  • Hydrocephalus

Intervention Strategies:
Psychoeducation for family members.
Behaviour Modification [Shaping, Chaining, Fading etc.] for reducing Behaviour problems – Temper tantrums, irritability, Restlessness, poor concentration, impulsiveness, and crying are common. Other disturbing behaviour, like aggression and self-injurious behaviour (such as head banging, biting, punching etc.). When such behaviour is severe and persistent, it can become a major source of stress for families.
Social Skill Training is improving a patient's ability to function in everyday social situations.
Occupational Therapy for Adjustment of daily living (ADL Training), fine motor control training necessary to perform concentrated tasks like drawing, lacing, writing which later form the basis of more advanced self help or academic skills.
Vocational training
Convulsion- pharmacological intervention
Sensory impairments: [Hearing difficulties, vision difficulties etc] Specialist consultation.