© Cengage Learning 2016 Eric J. Mash David A. Wolfe Intellectual Disability (Intellectual Developmental Disorder) 5

© Cengage Learning 2016 © Cengage Learning 2016

Eric J. MashDavid A. Wolfe

Intellectual Disability (IntellectualDevelopmental Disorder)

5

© Cengage Learning 2016

• Prior to mid-19th century: children and adults with intellectual disabilities were ignored or feared even by the medical profession

• Intellectual disability: a significant limitation in intellectual functioning and adaptive behavior which begins before age 18

Intelligence and Intellectual Disability (ID)


• In the mid-19th century: Samuel G. Howe opened the first humanitarian institution in North America

• By the 1940s: parents increased humane care for their children

Intelligence and Intellectual Disability (cont’d.)


• 1950: National Association for Retarded Children was formed

• 1962: President John F. Kennedy formed the President’s Panel on Mental Retardation

Intelligence and Intellectual Disability (cont’d.)


• Evolutionary degeneracy theory– Pervasive in 19th century

– Intellectual and social problems of children with mental retardation were viewed as regression to an earlier period in human evolution

– J. Langdon H. Down interpreted “strange anomalies” as throwbacks to the Mongol race

The Eugenics Scare


• Eugenics: “the science dealing with all influences that improve the inborn qualities of a race” ~ Sir Francis Galton– Led to the view that individuals with ID (moral

imbeciles, or morons) were threats to society

The Eugenics Scare (cont’d.)


• Alfred Binet and Theophile Simon (1900s)– Commissioned by the French government to

identify schoolchildren who might need special help in school

– Developed the first intelligence tests• Measure judgment and reasoning of school

children (Stanford-Binet scale)

Defining and Measuring Children’s Intelligence and Adaptive Behavior


• General intellectual functioning is now defined by an intelligence quotient (IQ or equivalent)

• ID is no longer defined on the basis of IQ– Level of adaptive functioning is also important

• Adaptive functioning: how effectively individuals cope with ordinary life demands and how capable they are of living independently

Defining and Measuring Children’s Intelligence and Adaptive Behavior (cont’d.)


Specific Examples of Adaptive Behavior Skills


• IQ is relatively stable over time– Except when measured in young, normally-

developing infants

• Mental ability is always modified by experience

• The Flynn Effect: the phenomenon that IQ scores have risen about three points per decade

• Are IQ tests biased or unfair?

The Controversial IQ


• Clinical description - considerable range of abilities and interpersonal qualities– DSM-5 diagnostic criteria

• Deficits in intellectual functioning

• Concurrent deficits or impairments in adaptive functioning

• Below-average intellectual and adaptive abilities must be evident prior to age 18

Features of Intellectual Disabilities


Diagnostic Criteria for Intellectual Disability


• About 85% of persons with ID

• Typically not identified until early elementary years

• Overrepresentation of minority group members

• Develop social and communication skills

• Live successfully in the community as adults with appropriate supports

Severity Level: Mild


• About 10% of persons with ID

• Usually identified during preschool years

• Applies to many people with Down syndrome

• Benefit from vocational training

• Can perform supervised unskilled or semiskilled work in adulthood

Severity Level: Moderate


• About 3%-4% of persons with ID

• Often associated with organic causes

• Usually identified at a very young age– Delays in developmental milestones and

visible physical features are seen

• May have mobility or other health problems – Need special assistance throughout their lives

– Live in group homes or with their families

Severity Level: Severe


• About 1%-2% of persons with ID

• Identified in infancy due to marked delays in development and biological anomalies

• Learn only the rudimentary communication skills

• Require intensive training for:– Eating, grooming, toileting, and dressing

behaviors

• Require lifelong care and assistance

Severity Level: Profound


Examples of Support Areas


• Approximately 1-3% of population (depending on cutoff)

• Twice as many males as females among those with mild cases

• More prevalent among children of lower SES and children from minority groups, especially for mild cases– More severe levels - identified almost equally

in different racial and economic groups

Prevalence


Factors Accounting For Racial Differences


• Developmental-versus-difference controversy– Do all children—regardless of intellectual

impairments—progress through the same developmental milestones in a similar sequence, but at different rates?

• Developmental position– Similar sequence hypothesis

– Similar structure hypothesis

Developmental Course and Adult Outcomes


• Difference viewpoint: cognitive development of children with ID is qualitatively different in reasoning/problem-solving– Familial versus organically based ID

Developmental-Versus-Difference Controversy (cont’d.)


• Many children with mild ID are able to learn and attend regular schools

• Often susceptible to feelings of helplessness and frustration in their learning environments

• Children who have mild ID are able to stay on task and develop goal-directed behavior – With stimulating environments and caregiver

support

Motivation


• IQ scores can fluctuate in relation to the level of impairment

• Major cause of ID affects the degree to which IQ and adaptive abilities may change

• Slowing and stability hypothesis– IQ of children with Down syndrome may

plateau during middle childhood, then decrease over time

Changes in Abilities


• Development follows a predictable and organized course

• Characteristics displayed with Down syndrome– The underlying symbolic abilities of children

are believed to be largely intact

– There is considerable delay in expressive language development; expressive language is weaker than receptive language

Language and Social Behavior


• Fewer signals of distress or desire for proximity with primary caregiver

• Delayed, but positive, development of self-recognition

• Delayed and aberrant functioning in internal state language– Reflects emergent sense of self and others

• Deficits in social skills and social-cognitive ability; can lead to rejection by peers

Characteristics Displayed With Down Syndrome (cont'd.)


• Rate is three to seven times greater than in typically developing children– Largely due to limited communication skills,

additional stressors, and neurological deficits

• Most common psychiatric diagnoses:– Impulse control disorders, anxiety disorders,

and mood disorders

• Internalizing problems and mood disorders in adolescence are common

Emotional and Behavioral Problems


• ADHD-related symptoms are common

• Pica is seen in serious form among children and adults with ID

• Self-injurious behavior (SIB)– Can be life-threatening

– Affects about 8% of persons across all ages and levels of ID

Emotional and Behavioral Problems (cont'd.)


• Health and development are affected

• Degree of intellectual impairment is a factor

• Prevalence of chronic health conditions in ID population is much higher than in the general population

• Life expectancy for individuals with Down syndrome is now approaching 60 years

Other Physical and Health Disabilities


Chronic Health Conditions Among Children With Intellectual Disabilities


• Scientists cannot account for the majority of cases, especially the milder forms

• Genetic or environmental causes are known for almost two-thirds of individuals with moderate to profound ID

Causes


• Prenatal: genetic disorders and accidents in the womb

• Perinatal: prematurity and anoxia

• Postnatal: meningitis and head trauma

Prenatal, Perinatal, and Postnatal Causes


• Organic group – there is a clear biological basis– Associated with severe and profound MR

• Cultural-familial group – there is no clear organic basis– Associated with mild MR

The Two-Group Approach


• Four major categories of risk factors – Biomedical

– Social

– Behavioral

– Educational

Risk Factors


CausesRisk Factors (cont'd.)


• Genetic influences are potentially modifiable by environment

• Genotype: a collection of genes that pertain to intelligence

• Phenotype: the expression of the genotype in the environment (gene-environment interaction)

Inheritance and the Role of the Environment


• Heritability describes the proportion of the variation of a trait attributable to genetic influences in the population– Ranges from 0% to 100%

– The heritability of intelligence is about 50%

• Major environmental variations affect cognitive performance and social adjustment in children from disadvantaged backgrounds

Inheritance and the Role of the Environment(cont'd.)


• Chromosome abnormalities– Down syndrome is usually the result of failure

of the 21st pair of the mother’s chromosomes to separate during meiosis ► causes an additional chromosome

• Fragile-X syndrome is the most common cause of inherited ID

• Prader-Willi and Angelman syndromes– Both are associated with abnormality of

chromosome 15

Genetic and Constitutional Factors


• Single-gene conditions: inborn errors of metabolism– Excesses or shortages of certain chemicals

which are necessary during developmental stages

– Cause of 3-7% of cases of severe ID

– Phenylketonuria results in lack of liver enzymes necessary to metabolize phenylalanine

• Can be treated successfully

Genetic and Constitutional Factors (cont’d.)


• Adverse biological conditions– Examples: infections, traumas, and accidental

poisonings during infancy and childhood

• Fetal Alcohol Spectrum Disorder (FASD)– Estimated to occur in one-half to two per 1000

live births

• Teratogens increase risk of ID

Neurobiological Influences


• Least understood and most diverse factors causing ID

• Environmental influences and other mental disorders account for 15-20% of ID – Deprived physical and emotional care and

stimulation of the infant

– Other mental disorders accompanied by ID, such as autism

• Parents are critically important

Social and Psychological Dimensions


• Child’s overall adjustment is a function of:– Parental participation, family resources, social

supports, level of intellectual functioning, basic temperament, and other specific deficits

• Treatment involves a multi-component, integrated strategy– Considers children’s needs within the context

of their individual development, their family and institutional setting, and their community

Prevention, Education, and Treatment


• ID related to fetal alcohol syndrome, lead poisoning, rubella) can be prevented if precautions are taken

• Prenatal programs for parents caution about use of alcohol, tobacco, drugs, and caffeine during pregnancy

Prenatal Education and Screening


• Early intervention– One of the most promising methods for

enhancing the intellectual and social skills of young children with developmental disabilities

– Carolina Abecedarian Project provides enriched environments from early infancy through preschool years

– Optimal timing for intervention is during preschool years

Psychosocial Treatments


• Initially seen as a means to control or redirect negative behaviors

• Association for Behavior Analysis (ABA) Task Force advocates that:– Each individual has the right to the least

restrictive effective treatment and the right to treatment that results in safe and meaningful behavior change

Behavioral Approaches


• Self-instructional training and metacognitive training

• Verbal instructional techniques

• Teaching the child to be strategical and metastrategical

Cognitive-Behavioral Therapy


• Help families cope with the demands of raising a child with ID

• Some ID children and adolescents benefit from residential care or out-of-home placement

• The inclusion movement integrates individuals with disabilities into regular classroom settings – Curriculum is adapted to individual needs

Family-Oriented Strategies

Documents

© Cengage Learning 2016 Eric J. Mash David A. Wolfe Intellectual Disability (Intellectual Developmental Disorder) 5