Understanding Intellectual Disability: History, Measurement, and Support

1. 5 Intellectual Disability (IntellectualDevelopmental Disorder)

2. Intelligence and Intellectual Disability (ID) • 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

3. Intelligence and Intellectual Disability (cont’d.) • 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

4. 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

5. The Eugenics Scare • 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

6. The Eugenics Scare (cont’d.) • 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

7. Defining and Measuring Children’s Intelligence and Adaptive Behavior • 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)

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

9. Specific Examples of Adaptive Behavior Skills

10. The Controversial IQ • 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?

11. Features of Intellectual Disabilities • 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

12. Diagnostic Criteria for Intellectual Disability

13. Severity Level: Mild • 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

14. Severity Level: Moderate • 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

15. Severity Level: Severe • 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

16. Severity Level: Profound • 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

17. Examples of Support Areas

18. Prevalence • 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

19. Factors Accounting For Racial Differences

20. Developmental Course and Adult Outcomes • 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

21. Developmental-Versus-Difference Controversy (cont’d.) • Difference viewpoint: cognitive development of children with ID is qualitatively different in reasoning/problem-solving • Familial versus organically based ID

22. Motivation • 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

23. Changes in Abilities • 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

24. Language and Social Behavior • 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

25. Characteristics Displayed With Down Syndrome (cont'd.) • 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

26. Emotional and Behavioral Problems • 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 ddisorders, anxiety disorders, and mood disorers • Internalizing problems and mood disorders in adolescence are common

27. Emotional and Behavioral Problems (cont'd.) • 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

28. Other Physical and Health Disabilities • 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

29. Chronic Health Conditions Among Children With Intellectual Disabilities

30. Causes • 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

31. Prenatal, Perinatal, and Postnatal Causes • Prenatal: genetic disorders and accidents in the womb • Perinatal: prematurity and anoxia • Postnatal: meningitis and head trauma

32. The Two-Group Approach • 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

33. Risk Factors • Four major categories of risk factors • Biomedical • Social • Behavioral • Educational

34. CausesRisk Factors (cont'd.)

35. Inheritance and the Role of the Environment • 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)

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

37. Genetic and Constitutional Factors • 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

38. ImagesDown Syndrome-Moderate level of ID

39. Fragile X: Mild to Moderate; Males are more affected

40. Prader –WilliUrge to eat constantlyAbnormality on Chr. 15

41. Angelman Syndrome Moderate to severeAbnormality on Chr. 15 • Ataxia (strange walking) • Hand flapping, jerky movements • Absence of speech • Large jaw

42. PKU (Phenylketonuria) Single-gene recessive condition can be controlled with appropriate diet

43. Genetic and Constitutional Factors (cont’d.) • 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

44. Neurobiological Influences • 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

45. Fetal Alcohol Syndrome The most preventable form of ID • Central Nervous System Dysfunction • Growth retardation • Abnormities of facial features

46. Social and Psychological Dimensions • 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

47. Prevention, Education, and Treatment • 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

48. Prenatal Education and Screening • 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

49. Psychosocial Treatments • 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

50. Behavioral Approaches • 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