Mental Retardation

ERLYN LIMOA

Occurrence Mental retardation and physical disabilities

account for the population traditionally thought of as disabled.

Most teachers will work with these children in school.

This group makes up only a small portion of those classified as disabled, but may require a large part of the resources needed.

Definition Mental retardation refers to

significantly sub average general intellectual functioning, existing concurrently with deficits in adaptive behavior and manifested during the developmental period (AAMD definition). Test scores, social skills, and age of onset determine the placement.

Mental retardation has become recognized as a disorder because:

1. MR affects functioning in many aspects of everyday life

2. Children with MR may appear physically different

3. MR is a chronic condition, often apparent from early in life

4. MR is world-wide; many families have a member with MR

Intellectual functioning IQ = Mental Age/Chronological Age * 100.

The more severe the retardation the lower the ratio of MA/CA i.e. a ten year old with a MA of 5, IQ = 50.

The MR child will tend function closer to their CA in physical ability then in their mental functioning.

Mental RetardationSub average intelligence (IQ <

70: DSM-IV; <75: AAMR)Associated adaptive deficits in at

least two areas:◦Communication, self-care, home

living, social skills, community use, self-direction, health and safety, functional academics, leisure, and work

Occurrence of deficits before age 18• DSM-IV : Diagnostic and Statistical Manual of Mental

Disorders IV• AAMR : American Association on Mental Retardation

Classification of Mental Retardation

Level of MR IQ range % of MR

Mild 50-69 80

Moderate 40-49 10

Severe 25-39 3-4

Profound < 25 1-2

Prevalence Between 1% and 3% of the population

meet the criteria for Mental Retardation

Slightly more males than females with MR

Mild MR identified more in low SES and some minority groups, especially the impoverished. No such differences with severe or profound MR

Etiology◦ Prenatal

◦ Mothers < 16 or > 40 years old◦ Congenital infections : TORCH (Toxoplasmosis,

Rubella, CMV, Herpes simplex.

◦ Perinatal◦ Birth trauma and hypoxia◦ Prematurity : intraventricular haemorrhage,

hyperbilirubinemia.

◦ Genetic (most common)• Down’s syndrome – trisomy 21 (1/700 live birth)• Fragile X syndrome – 2nd most common cause of

retardation ; involves mutation of X chromosome ; affects males more than females.

Prevention Adequate prenatal care for all mothers prevents many

conditions that result in MR Informing parents of the genetic basis for some types

of MR Effective prevention and treatment programs for

maternal substance use and addiction Public health ads to prevent pregnant women from

smoking, drinking, doing unhealthy diets and illicit drugs

Parenting instruction for all new parents Instruction in behavior therapy techniques for parents

with children with MR and other disorders

ManagementComprehensive education and vocational

programmes.Family education and support.Behaviour therapy (aggressive and destructive

behaviour)Medication only given to manage destructive

and aggressive behaviour (antipsychotics, benzodiazepines, lithium & carbamazepine)

Appropriate residential placement.Treatment of co-morbid psychiatric & medical

condition.

Comprehensive Early Intervention Programs May serve children at risk because of low birth

weight, premature birth, mild MR in the family Expert home visitors work with the family during

first 3 years of child’s life Mothers given instruction and practice in ways to

facilitate cognitive and social development and foster good physical health. Also stress-control for the mothers

Children in daily child development center with special education teachers and small groups

Parent support groups to help parents cope with the stresses of parenting

Mainstreaming Placing children with MR in regular

classrooms to “normalize” their behavior and give them more opportunities.

Effects are controversial. Studies show they are often shunned by regular students, may not receive the special education they need, and the poor and ethnically different children are too often mistakenly identified as MR

Down syndrome Down syndrome children are

characterized by a distinctive set of physical characteristics. These physical characteristics need to be factored in program planning.

Needs The MR child will need modifications in

rules and simplification of directions to perform in class activities.

Their skill and fitness level tends to be below normal.

Studies show that the MR child can develop skills and fitness with instruction and practice.

Programming Children with Mental Retardation can

benefit from physical activity. Programming needs to be inclusive as

much as possible.

Summary

Mental Retardation is defined partly by an IQ score under approximately 70 and multiple deficits in adaptive behavioral functioning in everyday life.

The DSM recognizes four levels of mental retardation as measured by IQ, ranging from mild (the most frequent) to profound.

Mental Retardation can spring from many different biological and social-environmental factors, with the most severe forms usually having biological roots. These include:

1. Metabolic disorders

2. Chromosomal Disorder

3. Prenatal Infections and Toxic Substances

4. Birth Injuries

5. Head Traumas

6. Many Others

Milder MR is usually treated with– 1. Behavioral Instruction– 2. Early Intervention Programs– 3. Special Education– 4. Mainstreaming

More severe MR is treated by:– 1. Behavior Therapy– 2. Drugs to control aggression and self-injurious

behavior– 3. Either home care or institutionalization

Wide availability of prenatal care for mothers and parenting instruction could significantly reduce the occurrence of MR