1、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 Shift from mental r
2、etardation to intellectual disability Definition Evolving Assessment Balance between intelligence and adaptive behavior Implications Increasing consistency,Issue of Change - Terminology,Historical conceptualizations Presence of individuals with intellectual impairments in society has been well docum
3、ented 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,Classification,A classification system is introduced J. Langdon Hayden Down Classification by physical a
4、ppearance Late 1800s: Recognition of brain pathology in intellectual disabilities Education reform and Residential Schools Theodore Simon and Alfred Binet Early 1900s Classification based on IQ,What is Intellectual Disability?,Current Perspective A state of functioning rather than a person-centered
5、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,What is Intellectual Disability?,Types of causes Genetic Chromosomal Prenatal influences
6、 Perinatal influences Postnatal influences Diagnosis of intellectual disability is a process No single diagnostic test Defined by many organizations,Terminology Differences,Many different terms to describe intellectual disability Shift in terminology in last few years Mental Retardation / Intellectu
7、al Disability Significant limitations in intellectual functioning and in adaptive behavior Before 18 Population of application remains the same (www.aaidd.org),Terminology Differences,Developmental Disability A severe, chronic disability that begins any time from birth through age 21 and is expected
8、 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),Terminology Di
9、fferences,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,Issue of
10、 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,Devel
11、opment 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,2002 AAIDD System,Diagnosis Es
12、sential 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,2002 AAIDD System,Multidimensional Approach Other systems, like DSM IV, is multi-axial and focus
13、es on medical disorders and stressors Important to assess current functioning and strengths of individual,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 i
14、n conceptual, social, and adaptive skills Originates before age 18,2002 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 inform
15、ation to develop support needs With personalized supports provided over time, life functioning will improve,2002 AAIDD System: Intelligence,General mental capacity includes: Reasoning Problem-solving Abstract thinking Comprehension Learning from experience Limitations influence other aspects of func
16、tioning Best represented by intelligence test scores using appropriate test instruments,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
17、 Self-directions,2002 AAIDD System: Adaptive Behavior,Social Skills Interpersonal skills Responsibility Self-esteem Practical Skills Eating Dressing/Bathing Mobility Daily Living tasks,2002 AAIDD System: Classification,Classification Dimension I Intellectual Abilities Dimension II Adaptive Behavior
18、Dimension III Participation, Interactions, and Social Roles Dimension IV Health Dimension V Context,2002 AAIDD System: Supports,Planning Supports Human development Teaching and education Home living Community living Employment Health and safety Behavioral Social Protection and advocacy,DSM IV TR Def
19、inition,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 c
20、ommunity resources, self-direction, functional academic skills, work leisure, health, and safety (American Psychiatric Association, 2000, p. 41) Onset before age 18,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 limitat
21、ions 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,Who are the Intellectually Disabled?,Prevalence Less than 1% of the overall population Estimated 3% of the population in the United States Residence WI Approxi
22、mately 81% reside in a home/supported living setting Approximately 19% reside in a state public/private facility (www.cu.edu/ColemanInstitute/stateofthestates/Wisconsin.html),Special Education Services Fall 2005,Site: www.ideadata.org,Special Education Services Fall 2005,Site: www.ideadata.org,Who a
23、re 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,Who are the Intellectually Disabled?,Associated impairmen
24、ts 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,Who are the Intellectually Disabled?,Psychiatric disorders Estimates o
25、f 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 disorderDeb, Thomas, & Bright 2001,Profiles of Intellectual Disability,Mild ID Profile Minor delays in the preschool period Evaluation oft
26、en 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 vocatio
27、nal possibilities,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, si
28、mple conversations, and cooperative social interactions Mental age of 6-8 years of age Vocational opportunities limited to unskilled work with direct supervision and assistance,Profiles of Intellectual Disability,Severe ID Profile Identification in infancy to two years Often co-occurring with biolog
29、ical 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,Profiles of Intellectual Disability,Profoun
30、d 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 b
31、irth to 4 years of age Functional skill acquisition not likely,Variations in ID Classification,Childhood intervention history Educational experiences Socialization opportunities Adult habilitative and prevocational activities Presence of physical impairment,Issue of Change - Assessment,Assessment Es
32、tablishing a balance between the importance of IQ and identifying functional behaviors and support needs Increased recognition of the cultural implications of intelligence testing,Identifying Individuals with ID,Assessment Cognitive/intellectual ability Adaptive behavior functioning,Cognitive Abilit
33、y 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 individuals test performance in comparison to the average performance or “norm”, of other individuals of th
34、e same chronological age Validity and Reliability Validity: Does the test measure what we want? Reliability: Does the test measure consistently?,Cognitive Ability Assessment,Normal Curve / Distribution Represents the distribution of abilities in the general population Demonstrates the extent to whic
35、h 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%,Cognitive Ability Assessment,Normal Curve,Cognitive Ability Assessment,Types of Intell
36、igence Verbal Ability Nonverbal Ability Other theoretical models,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,Cognitiv
37、e 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,Other Consideration in Cognitive Ability Assessment,How reliable and valid was the test O
38、ther Important Features: culture, language barriers, physical impairments Ability to accurately compare individuals 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 individu
39、als and their families Also consider if there was a great deal of scatter within the individuals 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 ar
40、e 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
41、,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),Adaptive Behavior Assessment,Adaptive behav
42、ior 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,Adaptive Behavior Assessment,Adaptive Behavior Conceptual Skills:communication, functiona
43、l academics, self-direction, money concepts Social Skills:interpersonal skills, self-esteem, naivet/gullibility, self-governance (obeys rules) Practical Skills:self-care, domestic skills, work, health & safety,Adaptive Behavior Assessment,Relationship between IQ and adaptive behavior functioning r =
44、 .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,Adaptive Behavior Assessment,Current standards of practice Assess present functioning Assess typical funct
45、ioning Consider the persons age and culture Assessment using standardized measure of AB normed on general population Compare persons adaptive behavior to community standards and expectations Use multiple informants Retrospective assessment (Schalock et al., 2007),Adaptive Behavior Assessment,Measure
46、s 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,Adaptive Beha
47、vior 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
48、2nd Edition (ABAS II) (Harrison & Oakland, 2003),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
49、 Consider the unique needs of all family members Need to be sensitive about dreams and hopes of parents for their children Need to respect familys coping style,Why Change?,Service Provision Effective resource utilization Lifetime expenditure - $51.2 billion for individuals with ID (www.cdc.org) Incr
50、eased emphasis on adaptive behavior functioning and habilitation services Utilizing support needs assessment as a tool towards improved interventions,Why Change?,Legal Implications Identifying individuals at risk as vulnerable adults Individuals within the criminal justice system As victims 4 to 10 times increased risk (Sobsey, 1994) As suspects/offenders 4-10% of the prison population (Sullivan & Knutson, 2000),
