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Lecture Presenter: Lara S. Head, Ph.D. Post Doctorate Fellow in Psychology Waisman Center

SW 644: Issues in Developmental Disabilities Intellectual Disability: Definition, Classification and Assessment. Lecture Presenter: Lara S. Head, Ph.D. Post Doctorate Fellow in Psychology Waisman Center University of Wisconsin-Madison. Issue of Change: Providing Context. Terminology

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Lecture Presenter: Lara S. Head, Ph.D. Post Doctorate Fellow in Psychology Waisman Center

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  1. SW 644: Issues in Developmental DisabilitiesIntellectual Disability: Definition, Classification and Assessment Lecture Presenter: Lara S. Head, Ph.D. Post Doctorate Fellow in Psychology Waisman Center University of Wisconsin-Madison

  2. Issue of Change: Providing Context • Terminology • Shift from ‘mental retardation’ to ‘intellectual disability’ • Definition • Evolving • Assessment • Balance between intelligence and adaptive behavior • Implications • Increasing consistency

  3. Issue of Change - Terminology • Historical conceptualizations • Presence of individuals with intellectual impairments in society has been well documented over time (Example: Roman and Greek Culture) • Early religious leaders were among first to advocate for humane treatment • Changing perceptions • John Locke • Jean-Marc-Gaspard Itard • Edouard Seguin

  4. Classification • A classification system is introduced • J. Langdon Hayden Down • Classification by physical appearance • Late 1800’s: Recognition of brain pathology in intellectual disabilities • Education reform and Residential Schools • Theodore Simon and Alfred Binet • Early 1900s • Classification based on IQ

  5. What is Intellectual Disability? • Current Perspective • A state of functioning rather than a person-centered trait • Limitations in intellectual functioning • Difficulties in meeting the ordinary challenges associated with daily life • A social-ecological view • Not an illness or a disease • Medical model view • Perception of ‘sick’

  6. What is Intellectual Disability? • Types of causes • Genetic • Chromosomal • Prenatal influences • Perinatal influences • Postnatal influences • Diagnosis of intellectual disability is a process • No single diagnostic test • Defined by many organizations

  7. Terminology Differences • Many different terms to describe intellectual disability • Shift in terminology in last few years • Mental Retardation / Intellectual Disability • Significant limitations in intellectual functioning and in adaptive behavior • Before 18 • Population of application remains the same (www.aaidd.org)

  8. Terminology Differences • Developmental Disability • A severe, chronic disability that begins any time from birth through age 21 and is expected to last a lifetime. • May be cognitive, physical, or a combination of both • Serious limitations in everyday activities (www.nacdd.org) • Disability • Personal limitations that represent a substantial disadvantage with attempting to function in society • Can originate at any age (www.aapd.org)

  9. Terminology Differences • Benefits to terminology change • Reflects the changed construct of disability • Aligns better with current professional practices • Provides a logical basis for individualized supports provision • Less offensive to individuals with disability • More consistent with international terminology

  10. Issue of Change- Definition • Definition • Evolving and dependent on assumptions that clarify the context from which it is derived and applied • Significant consequences • Service eligibility • Subject or not subject to certain practices • Exempted or not exempted • Included or not included • Entitled or not entitled

  11. Development of Definition • 1961: AAMR introduces term “mental retardation” • 1973: Introduction of standard deviation to describe intellectual disability as well as 18 as upper age limit for initial manifestation of intellectual disability • 1980s: Specific IQ values with ranges

  12. 2002 AAIDD System • Diagnosis • Essential to establishing eligibility • Classification • A means of communication • Planning Supports • Enhancing personal outcomes • Four different definitions for intellectual disability: focus on DSM IV and AAIDD

  13. 2002 AAIDD System • Multidimensional Approach • Other systems, like DSM IV, is multi-axial and focuses on medical disorders and stressors • Important to assess current functioning and strengths of individual

  14. 2002 AAIDD System • Diagnosis Core definition (2002) • Mental retardation is a disability characterized by significant limitations in intellectual functioning and in adaptive behavior • Is expressed in conceptual, social, and adaptive skills • Originates before age 18

  15. 2002 AAIDD System • 5 essential assumptions • Limitations must be considered within context • Diagnosis based on a valid assessment that considers various factors • Recognizes that limitations and strengths coexist • Limitations provide information to develop support needs • With personalized supports provided over time, life functioning will improve

  16. 2002 AAIDD System: Intelligence • General mental capacity includes: • Reasoning • Problem-solving • Abstract thinking • Comprehension • Learning from experience • Limitations influence other aspects of functioning • Best represented by intelligence test scores using appropriate test instruments

  17. 2002 AAIDD System: Adaptive Behavior • Collection of skills that individuals learn to use in order to function in everyday life • Conceptual Skills • Receptive and expressive language • Reading and writing • Money concepts • Self-directions

  18. 2002 AAIDD System: Adaptive Behavior • Social Skills • Interpersonal skills • Responsibility • Self-esteem • Practical Skills • Eating • Dressing/Bathing • Mobility • Daily Living tasks

  19. 2002 AAIDD System: Classification • Classification • Dimension I • Intellectual Abilities • Dimension II • Adaptive Behavior • Dimension III • Participation, Interactions, and Social Roles • Dimension IV • Health • Dimension V • Context

  20. 2002 AAIDD System: Supports • Planning Supports • Human development • Teaching and education • Home living • Community living • Employment • Health and safety • Behavioral • Social • Protection and advocacy

  21. DSM IV – TR Definition • Significantly below average intellectual functioning: IQ of approximately 70 or below on an individually administered IQ test • Accompanied by significant limitations in adaptive functioning in at least 2 skill areas: • Communication, self-care, home living, social/interpersonal skills, use of community resources, self-direction, functional academic skills, work leisure, health, and safety (American Psychiatric Association, 2000, p. 41) • Onset before age 18

  22. DSM IV-TR Levels of Mental Retardation • Mild MR • 55-70 IQ • Adaptive limitations in 2 or more domains • Moderate MR • 35-54 IQ • Adaptive limitations in 2 or more domains • Severe MR • 20-34 IQ • Adaptive limitations in all domains • Profound MR • Below 20 IQ • Adaptive limitations in all domains

  23. Who are the Intellectually Disabled? • Prevalence • Less than 1% of the overall population • Estimated 3% of the population in the United States • Residence • WI • Approximately 81% reside in a home/supported living setting • Approximately 19% reside in a state public/private facility (www.cu.edu/ColemanInstitute/stateofthestates/Wisconsin.html)

  24. Special Education Services – Fall 2005 Site: www.ideadata.org

  25. Special Education Services – Fall 2005 Site: www.ideadata.org

  26. Who are the Intellectually Disabled? • Age differences • Increased prevalence typically from preschool to middle childhood years • Increased prevalence in teen years • Decreased prevalence in older individuals • Gender differences • Increased reports in males

  27. Who are the Intellectually Disabled? • Associated impairments • 20-25% visually impaired • 10% hearing impaired • Seizure disorders occur in approximately 33% of individuals in institutional settings • Cerebral palsy occurs 30-60% of individuals in individuals with severe intellectual disability

  28. Who are the Intellectually Disabled? • Psychiatric disorders • Estimates of 4-18% of individuals with ID have a co-occurring psychiatric disorder • 4.4% Schizophrenia • 2.2% Depressive disorder • 2.2% Generalized Anxiety Disorder • 4.4% Phobic disorder Deb, Thomas, & Bright 2001

  29. Profiles 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

  30. Profiles of Intellectual Disability • 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

  31. Profiles of Intellectual Disability • 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

  32. Profiles of Intellectual Disability • 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

  33. Variations in ID Classification • Childhood intervention history • Educational experiences • Socialization opportunities • Adult habilitative and prevocational activities • Presence of physical impairment

  34. Issue of Change - Assessment • Assessment • Establishing a balance between the importance of IQ and identifying functional behaviors and support needs • Increased recognition of the cultural implications of intelligence testing

  35. Identifying Individuals with ID • Assessment • Cognitive/intellectual ability • Adaptive behavior functioning

  36. Cognitive Ability Assessment • Standardized and Norm-referenced Tests • Standardized: a test given in a certain, prescribed way using the same set of directions with every individual • Norm-referenced: Examining an individual’s test performance in comparison to the average performance or “norm”, of other individuals of the same chronological age • Validity and Reliability • Validity: Does the test measure what we want? • Reliability: Does the test measure consistently?

  37. Cognitive Ability Assessment • Normal Curve / Distribution • Represents the distribution of abilities in the general population • Demonstrates the extent to which individuals deviate from the mean based on a normal distribution of scores • Average IQ = 100 • Range 85-115 = approximately 68% • Fewer people are represented at the extreme ends of the curve • IQ < 70 = approximately 3%

  38. Cognitive Ability Assessment • Normal Curve

  39. Cognitive Ability Assessment • Types of Intelligence • Verbal Ability • Nonverbal Ability • Other theoretical models

  40. Cognitive Ability Assessment • Common Measures • WISC Series (WISC IV; WAIS II; WPPSI, etc.) • Stanford-Binet V • Woodcock-Johnson Test of Cognitive Abilities • Bayley Scales of Infant Development • Kaufman Assessment Battery for Children

  41. Cognitive Ability Assessment • Stability over time • For most, intelligence remains stable after 5 years of age (Zigler, Balla, & Hodapp, 1984) • However, variability in individual growth patterns warrant periodic evaluation

  42. Other Consideration in Cognitive Ability Assessment • How reliable and valid was the test • Other Important Features: culture, language barriers, physical impairments • Ability to accurately compare individual’s performance against a normative group when presence of some physical issues • Need to be vigilant with these issues when conducting testing, review the literature and talking to individuals and their families • Also consider if there was a great deal of scatter within the individual’s performance?    • Intellectual disability is a feature of many different conditions, many different disorders  • The diagnosis of intellectual disability should always be made whenever the diagnostic criteria are met regardless of whether or not there are other conditions that are present • Individuals with intellectual disability are vulnerable to lots of other conditions simply by the nature of how they do function and the nature by which their ability to execute their skills effectively can be compromised

  43. Adaptive Behavior Assessment • “The adaptive behavior approach was originally intended to encourage one to look at the individuals with an eye toward remediation and prescriptive assessment, rather than merely labeling and classifying.” (Nihira, 1999, p. 8)

  44. Adaptive Behavior Assessment • Adaptive behavior can be difficult to assess: • Adaptive behavior is not independent of intelligence • Behaviors accepted as adaptive at one age may not be acceptable at another age • What constitutes adaptive behavior is variable

  45. Adaptive Behavior Assessment • Adaptive Behavior Conceptual Skills: communication, functional academics, self-direction, money concepts Social Skills: interpersonal skills, self-esteem, naiveté/gullibility, self-governance (obeys rules) Practical Skills: self-care, domestic skills, work, health & safety

  46. Adaptive Behavior Assessment • Relationship between IQ and adaptive behavior functioning • r = .30 -.50 (Harrison & Oakland, 2003) • Highest correlation in the lower IQ ranges • More variability in adaptive behavior scores in higher IQ ranges • Adaptive behavior and intelligence work together

  47. Adaptive Behavior Assessment • Current standards of practice • Assess present functioning • Assess typical functioning • Consider the person’s age and culture • Assessment using standardized measure of AB normed on general population • Compare person’s adaptive behavior to community standards and expectations • Use multiple informants • Retrospective assessment (Schalock et al., 2007)

  48. Adaptive Behavior Assessment • Measures • Vineland II Adaptive Behavior Scales (Sparrow, Cicchetti, & Balla, 2005) • Birth to age 90 • Three versions • Four Domains – Communication, Daily Living Skills, Socialization, Motor Skills • Maladaptive Behavior Domain • Adaptive behavior composite score • Survey scale norms based on 3,000+ people

  49. Adaptive Behavior Assessment • Measures • AAMR Adaptive Behavior Scales (ABS) • School/Community (Lambert, Nihira, & Leland, 1993) • Residential/Community (Nihira, Leland, & Lambert, 1993) • Scales of Independent Behavior– Revised (SIB-R) (Brunininks, Woodcock, Weatherman, & Hill, 1996) • Adaptive Behavior Assessment System 2nd Edition (ABAS – II) (Harrison & Oakland, 2003)

  50. Why Change? - Implications • Professional-Parent Communication • Maximize the role of professional in shaping parent perceptions • Recognize the adaptation process as an evolving experience for parents • Need to listen to and value the perspectives of parents • Consider the unique needs of all family members • Need to be sensitive about dreams and hopes of parents for their children • Need to respect family’s coping style

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