2.1 Definition, Types and Characteristics

There are many definitions of mental retardation, the most comprehensive among them is the one given by the American Association on Mental Retardation (AAMR) 1983 restated till 2004.

The Mental Deficiency Act of 1921 in England considered “Mental defectiveness as a condition of arrested or in complete development of mind existing before the age of eighteen years, whether arising from inherent causes or induced by disease or injury.

“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.” (AAIDD, 2010)

“Mental retardation means a condition of arrested or incomplete development of mind of a person which is specially characterized by sub normality of intelligence.” (PWD act, 1995)

 “Mental retardation is a condition of  arrested or incomplete development  of the mind, which is especially characterized by impairment of skills manifested during the developmental period, that contribute to cognitive (knowledge), language, motor and social abilities.” (WHO, ICD-10)

Causes of Intellectual Disability

Prenatal (before birth)

·        chromosomal, maternal infections, environmental factors, unknown influences

Perinatal (during birth)

·        gestational disorders, neonatal complications

Postnatal (after birth)

·        infections and intoxicants, environmental factors

Predisposing Factors

§  No clear etiology can be found in about 75% of those with Mild MR and 30 – 40% of those with severe impairment

§  Specific etiologies are most often found in those with Severe and Profound MR

§  No familial pattern (although certain illnesses resulting in MR may be heritable)

Heredity (5% of cases)

       Autosomal recessive inborn errors of metabolism (e.g., Tay-Sachs, PKU)

       Single-gene abnormalities with Mendelian inheritance and variable expression (e.g., tuberous sclerosis)

       Chromosomal aberrations (e.g., Fragile X)

§  Early Alterations of Embryonic Development (30% of cases)

       Chromosomal changes (e.g., Downs)

       Prenatal damage due to toxins (e.g., maternal EtOH consumption, infections)

§  Environmental Influences (15-20% of cases)

       Deprivation of nurturance, social/linguistic and other stimulation

§  Mental Disorders

       Autism & other PDDs

§  Pregnancy & Perinatal Problems (10% of cases)

       Fetal malnutrition, prematurity, hypoxia, viral and other infections, trauma

§  General Medical Conditions Acquired in Infancy or Childhood (5% of cases)

       Infections, trauma, poisoning (e.g., lead)


Types of Intellectual Disability

AAMR Classification Scheme

     I.Q.(intelligence quotient) is 100; normal ranges from 90 to 110

·        Border line { IQ 70-80 }

·        mild MR     { IQ 55-70 }

·        moderate MR{ IQ 40-55 }

·        sever MR      { IQ 25-40 }

·        profound MR { IQ below 25 }

DSM IV-TR Levels of Mental Retardation

Ø   Mild MR

o          55-70 IQ

o          Adaptive limitations in 2 or more domains

Ø   Moderate MR

o          35-54 IQ

o          Adaptive limitations in 2 or more domains

Ø   Severe MR

o          20-34 IQ

o          Adaptive limitations in all domains

Ø   Profound MR

o          Below 20 IQ

o          Adaptive limitations in all domains

AAMR Levels of Support

Intermittent - Support is not always needed. It is provided on an "as needed" basis and is most likely to be required at life transitions (e.g. moving from school to work ).

Limited - Consistent support is required, though not on a daily basis. The support needed is of a non-intensive nature.

Extensive - Regular, daily support is required in at least some environments (e.g. daily home-living support).

Pervasive - Daily extensive support, perhaps of a life-sustaining nature, is  required in multiple environments.

Characteristics of Intellectual Disability


Mild ID Profile

·        Minor delays in the preschool period

·        Evaluation often only after school entry

·        2-3 word sentences used in early primary grades

·        Expressive language improvement with time

·        Reading/math skills – 1st to 6th grade levels

·        Social interests typically age appropriate

·        Mental age range of 8-11 years of age

·        Persistent low academic skill attainment can limit vocational possibilities


Moderate ID Profile

·        More evident and consistent delays in milestones

·        At school entry may communicate with single words and gestures

·        Functional language is the goal

·        School entry self-care skills – 2-3 year range

·        By age 14:  basic self-care skills, simple conversations, and cooperative social interactions

·        Mental age of 6-8 years of age

·        Vocational opportunities limited to unskilled work with direct supervision and assistance


Severe ID Profile

·        Identification in infancy to two years

·        Often co-occurring with biological anomalies

·        Increased risk for motor disorders and epilepsy

·        By age 12:  may use 2-3 word phrases

·        Mental age typically 4-6 years of age

·        As adults assistance typically required for even self-care activities

·        Close supervision needed for all vocational tasks


Profound ID Profile

·        Identification in infancy

·        Marked delays and biological anomalies

·        Preschool age range may function as a 1-year-old

·        High rate of early mortality

·        By age 10:  some walk/acquire some self-care skills with assistance

·        Gesture communication

·        Recognizes some familiar people

·        Mental age range from birth to 4 years of age

·        Functional skill acquisition not likely

Differentiation between Mental Retardation and Mental illness


Mental illnes


Mental Retardation


§  It is an illness/ disease/disorder.

§  Can occur at any age.

§  It is a disease of brain or psyche producing significant behavioural or psychological disturbances associated with socio-occupational deterioration.

§  Causes: Multifactorial- Biological, Psychological, Social.

§  Clinical features : No developmental delay. IQ level can be normal or below normal.It means mentally retarded can have mental illness; infact  rate of mental illnesses amongst mentally retarded is very high in comparison to the individual with normal IQ. Speech can be irrelevant. Behavioral change is noted. Will have normal premorbid state.

§  Classification: Broadly divided into psychoses and neuroses.


§  Course: Usually fluctuating but can be progressive or static.

§  On early identification completely reatable.

§  It is a condition, not a disease.

§  Usually at childhood, can occur during the developmental period.

§  Below average general intellectual functionong originating during the developmental period and associated with impairment in adaptive behaviour.

§  Multifavtorial but orimarily biological. Psychosocial factors may also cause.

§  Usually developmental delay is noted. IQ is below 70. Behavioural problems may be there. Deficits in adaptive behaviour and learnng are noted. Usually no premorbid state.

§  Depending on the IQ level (mild, moderate, severe & profound).

§  Usually static but can be progressive.

§  If identified and intervened early, development and learning can be enhanced.



2.2 Tools and Areas of Assessment


      A procedure by which accurately categorizes individuals as possibly handicapped or delayed.

      Primary concern is identification of those for whom more complete diagnostic study (further assessment) is necessary.

      It does not indicate that a person is handicapped or delayed

      Formal and informal observation and frequency counts of observed behavior are frequently used.

Screening Procedures

Prenatal Screening

Blood test in the mothers

·        Hemoglobin levels      

·        Glucose level

·        VDRL (Venereal Disease Research Laboratory  Test)

·        Blood group and Rh

·        Blood antibody titers for TORCHS


·        Neural tube defects like microcephaly, hydrocephaly, etc can be identified during II trimester.

·        Intra Uterine Growth Retardation

Maternal Serum AFP (Alpha-fetoprotein)

·        16-18 weeks of pregnancy

·        Detect spina-bifida, anencephaly, down’s syndrome etc

·        Not accurate indicator, only suggests further testing

Chorionic villus sampling

·        7th to 9th week of pregnancy

·        It shows chromosomal abnormalities carried by the fetus.

·        Tiny piece of chorionic villous tissue from placenta is removed and tested.

Multiple marker screening

·        15th to 20th week of pregnancy

·        Screen NTD, trisomy – 21, and trisomy – 18

·        Done by a blood test – measures the following

1.     1. hCG (human chorionic gonadotropin), which is        made by the

2.     placenta

3.     2. estriol, which is made by the placenta and the fetus

4.     3. alpha-fetoprotein (AFP), which is made by the fetus


·        16th week

·        Detects down’s syndrome, Tay-sachs, sickle cell anemia, and many other genetic disorders

·        Women reached 35 yrs of age

·        Withdrawal of a sample of fluid surrounding the fetus

·        0.06% chance of miscarriage


  A small (3–4 mm) incision is made in the abdomen, and an endoscope is inserted through the abdominal wall and uterus into the amniotic cavity. 

Neonatal Screening


                        A – Appearance (colour)

                        P –pulse rate (Heart rate)

                        G – Gravity (Muscle tone of extremities)

                        A – Activity (response to catheter)

                        R – Respiratory effort

Scoring 8 to 10 is normal. Below 7 high risk infant

Urine test for metabolic disorders

Post-natal Screening


  For intracranial pathology

  Reveals intra cranial hemorrhage, displacement of brain midline structures, pathological cavities.


Computerised Tomography

      Detects anoxia of tissue, intracranial hemorrhage, hydrocephalous, and congenital anomalies like congenital cysts, calcifications etc.


Blood chemical tests in neonatal screening

      Identify metabolic disorders, cretinism

      Tandom mass spectrometry - can screen for more than 20 inherited metabolic disorders with a single drop of blood

      Genetic Counseling


Assessment is a continuous process for understanding individual and programming required services for him. It involves collection and organization of information for specifying and verifying problems and for making decisions about a student. The decision may include a wide spectrum ranging from screening and identification to the evaluation of teaching plan.

The selection of assessment tools and methods vary depending on the purpose for the assessment is carried out.

  Stage 1 – To screen and identify those students with potential problems.

  Stage 2 – To determine and evaluate the appropriate teaching programme and strategies for particular student.

  Stage 3 – To determine the current level of functioning and educational needs of a student


NIMH has developed quick Screening Schedule I (Below 3 years) and Screening Schedule II (3 to 6 years).

Other screening tools-

  Cooperative preschool inventory-Caldwell.

  Croydon Scales (Screening Checklist)(Wolfendale & Bryans).

   Denver Developmental Screening Test (Frankensberg, Dodds and Fandal).

  Early Childhood Assessment: A criterionreferenced screening device (Schmaltz,Schramn and Wendt).


  Developmental Screening Test (DST) by Bharat Raj is a widely used screening tool.

  Upanayan Early Intervention Programming System (1987).

   Functional Assessment Check List for Programming (FACP) 1991.

  The revised Madras Developmental Programme System Behavioural Scale MDPS-A curriculum based assessment checklist (1975) is suitable for identification purposes.


  NIMH (Vocational Assessment and Programming Systems for Persons with Mental Retardation)

2.3 Strategies for Functional Academics and Social Skills

Relevance of Functional Academics:

Learning functional academic skills for children with Mental Retardation is necessary in order to become independent and successfully seek employment. Declaration of UNESCO towards “Education for All” in 2000 AD, includes children with disabilities, this also addresses learning needs of students with Mental Retardation. Literacy skills of individuals with Mental Retardation are not the same as children with other special needs due to the limited intellectual capacity. However, individuals with Mental Retardation can use literacy and numeracy skills to some extent which are application-oriented if they are given right kind of training.


      Provide activities that focus on reading for information and leisure

      Provide activities that require the child to become more aware of his/her surrounding environment having the child list the names of all food stores in the community, or all hospitals and so on will increase his/her familiarity with the surrounding environment.

      Have the child collect food labels and compare the differences

      Allow them look up the names of the children's families in the phone book. Use the smaller local guide for this activity.

      Develop activities that will allow them to become familiar with menus, bus and train schedules, movie and television timetables, or job advertisements.


      Have the child make a list of things to do for the day.

      Have the child run a messenger service in the classroom so that he/she can write the messages and deliver them from one student to another.

      Provide activities for older children that incorporate daily writing skills necessary for independency such as social security forms, driver’s license application, and bank account applications and so on.


      Have the child buy something at the school store

      Have the child make up a budget on how they plan to use his/her allowance

      Encourage the child to cook in school or at home so that they can become more familiar with measurements

      Have the child record the daily temperature

      Involve the child in measuring the height of classmates

      Have older children apply for a loan or credit card

      Show the child how to use a daily planning book

      Provide activities that teach the child how to comparison-shop

      Provide the child with a make believe amount of money and a toy catalog and have them purchase items and fill out the forms.


·         Provide frequent opportunities for students to learn and socialize with typically developing peers.

·         Involve the student in group activities and clubs.

·         Provide daily social skills instruction.

·         Directly teach social skills, such as turn-taking, social distance, reciprocal conversations, etc.

·         Break down social skills into non-verbal and verbal components.

·         Explains rules / rationales behind social exchanges.

·         Provide frequent opportunities to practice skills in role-playing situations.

·         Provide opportunities to practice skills in many different environments.

·         Serve as a model for interactions with students.

·         Value and acknowledge each student’s efforts.

·         Provide many opportunities for students to interact directly with each other.

·         Work to expand the young child’s repertoire of socially mediated reinforcers (e.g. tickling, peek-a-boo, chase, etc.).

·         Ask students to imagine how their behavior might affect others.

·         Specifically comment on and describe what the student is doing.

·         Model tolerance and acceptance.

·         Provide opportunities for students to assume responsibilities, such as distributing papers.

·         Teach other students to ignore inappropriate attention-seeking behaviors.

·         Have other students (who demonstrate appropriate behavior) serve as peer tutors.

·         Be aware that some students may work better alone.

·         Carefully consider and monitor seating arrangements in the classroom.

·         If student is motivated by adult or peer attention, find ways to recognize positive contributions.

* Social Stories can be used to teach social skills to children with such disabilities as autism or intellectual disability. A situation, which may be difficult or confusing for the student, is described concretely. The story highlights social cues, events, and reactions that could occur in the situation, the actions and reactions that might be expected, and why. Social stories can be used to increase the student’s understanding of a situation, make student feel more comfortable, and provide appropriate responses for the situation.  We recommend that you incorporate visuals into the stories as well.  These visuals can be drawings created by the student, imported images from Google, picture symbols / icons, or photographs. 

2.4 Assistive Devices, Adaptations, Individualized Education Plan, Person Centered Plan, Life Skill Education

Assistive Devices

Any product or technology based devices which support the functional needs of people with disabilities and maximises their quality of life.

UN Convention on the Rights of Persons with Disabilities (UNCRPD) Member states are obligated to 'undertake or promote research and development of, and to promote the availability and use of new technologies, including information and communications, technologies, mobility aids, devices and assistive technologies'.

Assistive Devices are any device that can directly help persons with disabilities in undertaking activities of daily living, pursuing education, acquiring movement in the built environment, working and engaging in leisure activities.

Importance of Assistive Devices

      Assistive Devices are used as an adjunct to aid in ambulation (mobility), postural support, and positioning, to improve balance and in replacing the missing or decreased part.

      The Assistive Devices empower people with disabilities to live with dignity as equal members of society thereby enhancing their quality of life.

Self-help and communication devices

These devices are the adaptations that are made on the objects used for daily activities. e.g., a spoon, glass, plate, etc. to meet the needs.

      Eating and Drinking: Careful selection  of utensils  and certain adaptations to the material can help the child to overcome problems such as holding, lifting, involuntary movements and spilling

      Toileting: Children with intellectual disability can be helped to become independent (to the greatest extent possible) in their toileting if special aids or adaptations are made.

      Dressing: We can facilitate developing dressing skills by making certain adaptations in the material use for training, careful selection of the clothing and adaptations to the material can help them to overcome problems such as holding and pulling.


Adapting Curriculum for Children with Intellectual disability

A student can be defined as having a Intellectual disability if he/she exhibits certain learning, social and behavior patterns to a marked extent and over a prolonged period of time. Such patterns may include:

      A consistently sub-average intellectual level

      Impaired adaptive functioning in such areas as social skills, communication and daily living skills

      Consistently slow rate of learning and as a result their level of development resembles that of a younger child

      Delays in most areas of development

However, adaptations and a variety of techniques need to be utilized. Consequently, certain behaviors should be targeted as priorities when dealing with mentally disabled children in the classroom. These target areas include:

      Functional academics

      General Work Habits

      Career awareness

Individualized Educational Programm

Measures to formulate Individualized Educational Program are a key to meet learning challenges faced by students with Mental Retardation. This challenge is different in inclusive setting, because it does not privilege Teacher to focus on individual with disability but use techniques to include learning interests of children without disabilities as well. It may help if minimal information is shared regarding challenges at foundational level for teaching functional academics, which at times is a common concern of few other children in class from non-disability background.

Functional Reading:

Functional Reading is defined as a student’s actions or responses resulting from reading printed words (Brown and Parlmutter, 1971). Functional term is related to application of learnt skills in real community settings. Hence words selected for reading must be “functional” allowing the reader to become independent in community living. As stated by Polloway and Patton (1993), reading is the key to personal and social adjustment and for successful involvement in community activities.

Functional Writing:

One of the important mode of communication is written expression. This demands eye – hand coordination, motor co-ordination, sense of direction and recognition of symbols (pictures/letters/ numbers/words/punctuation etc). Some writing tasks require “left to right” orientation in horizontal direction (for writing words), whereas some tasks require vertical orientation (for writing numbers in arithmetic problems as in addition or subtraction).

Functional Arithmetic:

Numbers play an important role in our lives. Our communication involves reference to negotiating quantities. Schwartz and Budd (1983), define Functional Mathematics as “use of mathematics needed for vocational, consumer, social, recreational and home making activities”. Functional mathematics includes: At the preschool level of education and primary, the students need to count parts of the body, things in the classroom, blades of the fan, legs of an animal, table, fingers of one hand, etc.


Person Centered Plan

A person centered plan can help those involved with the focus person see the total person, recognize his or her desires and interests, and discover completely new ways of thinking about the future of the person." — Beth Mount & Kay Zwernik, 1988

Person Centered Planning is an ongoing problem-solving process used to help people with disabilities plan for their future. In person centered planning, groups of people focus on an individual and that person's vision of what they would like to do in the future. This "person-centered" team meets to identify opportunities for the focus person to develop personal relationships, participate in their community, increase control over their own lives, and develop the skills and abilities needed to achieve these goals. Person Centered Planning depends on the commitment of a team of individuals who care about the focus person. These individuals take action to make sure that the strategies discussed in planning meetings are implemented.


      To look at an individual in a different way.

      To assist the focus person in gaining control over their own life.

      To increase opportunities for participation in the community.

      To recognize individual desires, interests, and dreams.

      Through team effort, develop a plan to turn dreams into reality.

Life Skill Education

Life skill skills for students with special needs are very important and valuable for them to get in education. This skills education program is a part of life skill. With this provision is expected they will be able to live independently by not / less dependent on others. This skill training focuses on the various skills to produce a product in the form of real objects that are beneficial to life. By learning the various skills expected, children with special needs can gain a perceptual experience, appreciative experience, and creative experience. Children with disabilities include blind children, hearing impaired, mentally disabled, tuna barrel, gifted child, and children with specific learning difficulties. Seeing the disorder they have a very varied intelligence. so there are children who have a high cognitive disabilities, but also have a low cognitive. Some have a severe disability and some are mild. Seeing this condition the kind of life skills that are suitable to be developed are general life skills and vocational life skills for children with disabilities.

With basic cognitive skills being deficit, the student suffers from challenge of coordinating cognitive skills for decision, problem solving or interaction related needs. Cognitive skills are essential pre-requisites for learning life skills for daily needs termed as “Activities of Daily Living (ADL)”. Pre – requisites like attention, observation, memory, consequential thinking, concentration, synthesis of learnt concepts with new concepts are basic to our daily skills. If any of above listed potential falls short in co-ordination it results in inadequate or deficit level of functioning in ADL. Therefore if ADL training must result in meaningful outcomes, it must first ensure training of pre-requisite skills such as cognitive processes as listed above relating to using attention, observation, associating names with people, functions with persons and names with objects, persons and their roles.

2.5 Vocational Training and Independent Living


The Person with Disabilities act (Equal Opportunities, Protection of Rights and Full Participation  Act, 1995) is a major milestone in Indian legislation for differently abled persons. In India, attention to the vocational training of the differently abled has gained importance since the enactment of this law. Even though, many vocational training centres are present in Indian Territory, but the concern for transition from school to work has not been serious. National

Institute of Mentally Handicapped had developed NIMH Transition model for vocational training and employment for mentally challenged adults to suit to Indian context. It includes four stages and they are school training, planning for the transition, placing in employment and ongoing support services. The stage of planning for the transition involves community assessment, vocational assessment and individualized transition plan. The ongoing support services are extensive vocational training, provide additional remediation in academic subjects, to lead them towards independent living and attain quality of life, to organise social warming exercises for better acceptability in the work community, and to teach necessary skills needed to

succeed in carrier.


Objectives of vocational training:

      To provide need based and skill based vocational training

      To ensure involvement of the parents in the process of rehabilitation

      To create awareness on vocational training and rehabilitation among the parents/siblings

      To discuss the process of vocational training and components of job analysis

      To empower the trainees for self-advocacy

      To make Persons with Disabilities self-dependent in related trades

      To make them learn independent living skills in the community

      To make them aware about their rights

Defining Independent Living

Independent living is defined as “those skills or tasks that contribute to the successful independent functioning of an individual in adulthood” (Cronin, 1996). We often categorize these skills into the major areas related to our daily lives, such as housing, personal care, transportation, and social and recreational opportunities.

A living arrangement that maximizes independence and self-determination, especially of persons with disabilities living in a community

Independent Living Skills:

Gaining independence at home, at school, in the community and/or in the workplace is central to the development of self-reliance, confidence and daily functioning in society. Independence provides opportunities to interact and participate in daily activities that would otherwise be quite limited. Promoting independence starts in the pre-school years and continues throughout life. The focus of curriculum in relation to independent living will change as the student matures and reflects level of cognitive and physical functioning. It is important for students to be able to meet their potential and not be restricted by dependence on others in whatever choices they make throughout their lives. The transfer of independent living skills to everyday functioning is vital in order to become a self-sufficient and contributing member of society.

The strands of the Independent Living Domain include: 

      Personal Care

      Domestic Skills 

      Money Skills 

      Safety Skills