Introuction to Intellectual Disability

Ravi K M,

Assistant Professor

Lady Irwin College

University of Delhi

Intellectual Disability is one of those disabilities which were surrounded with lot of misconceptions and social practices. At the early period it was considered as the result of God’s Anger or the result of sin done by the parents and they were killed at birth or abandoned on woods. Different terms used to represent the persons with this disability were idiot, moron, feebleminded, dumb, imbecile etc. now we uses the term Intellectual Disability (ID).

The first systematic and documented program of intervention for ID was developed in France in 1799 by Jean-Marc Gespard Itard, medical doctor. He developed a skill based programme for wild boy of Aveyron, named later Victor by Itard. Eduoard Seguin took Itard's methods further and established a systematic program to teach ‘feebleminded’ people. Later in 1866 Seguin  published a book titled “Idiocy and Its Treatments in Physiological Methods".

Definition

There are different definitions of Intellectual Disability in which world widely accepted definition is that given by American Association on Intellectual and Developmental Disabilities (AAIDD) in the year 2010.It states that “Intellectual disability is a disability characterized by significant limitations both in intellectual functioning and in adaptive behavior, which covers many everyday social and practical skills. This disability originates before the age of 18.” 

In this definition Intellectual functioning means also called intelligence—refers to general mental capacity, such as learning, reasoning, problem solving, and so on. One criterion to measure intellectual functioning is an IQ test.  Generally, an IQ test score of around 70 or as high as 75 indicates a limitation in intellectual functioning.

Standardized tests can also determine limitations in adaptive behavior, which comprises three skill types:

Ø Conceptual skills—language and literacy; money, time, and number concepts; and self-direction.

Ø Social skills—interpersonal skills, social responsibility, self-esteem, gullibility, naïveté (i.e., wariness), social problem solving, and the ability to follow rules/obey laws and to avoid being victimized.

Ø Practical skills—activities of daily living (personal care), occupational skills, healthcare, travel/transportation, schedules/routines, safety, use of money, use of the telephone.

AAIDD stresses that professionals must take additional factors into account, such as

             ü Community environment typical of the individual’s peers and culture

ü Professionals should also consider linguistic diversity and cultural differences

ü Finally, assessments must also assume that limitations in individuals often coexist with strengths, and that a person’s level of life functioning will improve if appropriate personalized supports are provided over a sustained period

In India the legally accepted definition is that given in Persons with Disabilities (Equal Opportunities, Protection of Rights and Full Participation) Act 1995. The act states that Mental Retardation is “A condition of arrested or incomplete development of mind of a person which is specially characterized by sub normality of intelligence.”

Intellectual disability is majorly classified based on three factors they are Intelligence Quotient (IQ), Educational Functioning and Etiology.

Classification based on Intelligence Quotient (IQ) is known as Psychological Classification, which classify Intellectual Disability in to four

Types

                  Type                                      IQ Range

1.      Mild Intellectual Disability                 55-69

2.      Moderate Intellectual Disability         35-54

3.      Severe Intellectual Disability              20-34

4.      Profound Intellectual Disability          below 20

Educational Classification is based on present level functioning, it includes

1.      Educable (roughly equate with mild ID)

2.      Trainable (roughly equate with moderate and severe ID)

3.      Custodial (roughly equate with profound ID)

Medical Classification is based on Etiology or causes, it includes

1.      Chromosomal abnormality e.g., Down Syndrome

2.      Gestational disorders e.g., cord around neck

3.      Prenatal influences

4.      Metabolic Disorders e.g., Phenyl Ketoneuria (PKU)

5.      Brain Infections e.g., Meningitis

6.      Accidents or trauma

7.       Physical agents e.g., teratogens

8.      Other influences