Chapter 4 Intellectual Disabilities

1. Chapter 4Intellectual Disabilities

2. Definitions of Mental Retardation • IDEAdefinition • Significantly sub-average intellectual functioning • Deficits in adaptive behavior • Manifested during the developmental period • Three criteria for a diagnosis • Significant sub-average intellectual functioning - a score of two or more standard deviations below the mean on standardized intelligence tests • An individual must be well below average in both intellectual functioning and adaptive behavior • The deficits in intellectual functioning and adaptive behavior must occur during the developmental period to help distinguish mental retardation from other disabilities

3. Definitions of Mental Retardation (cont.) • AAIDD 2002 definition • Intellectual disability is a disability characterized by significant limitations in both intellectual functioning and in adaptive behavior as expressed in conceptual, social, and practical adaptive skills. This disability originates before age 18. • Four assumptions essential to understanding and appropriately applying the definition • Limitations in present functioning must be considered within the context of community environments typical of the individual’s age peers and culture. • Valid assessment considers cultural and linguistic diversity as well as differences in communication, sensory, motor, and behavioral factors. • Within the individual, limitations often coexist with strengths. • With appropriate personalized supports over a sustained period, the life functioning of the person with intellectual disability generally will improve.

4. Identification and Assessment Assessing Intellectual Functioning • Standardized tests are used to assess intelligence • A diagnosis of MR requires an IQ score at least 2 standard deviations below the mean (70 or less) • Important considerations of IQ tests: • IQ is a hypothetical construct • IQ tests measure how a child performs at one point in time • IQ tests can be culturally biased • IQ scores can change significantly • IQ testing is not an exact science • Results are not useful for targeting educational objectives • Results should never be used as the sole basis for making decisions regarding special education services

5. Assessing Adaptive Behavior • Adaptive behavior is the collection of conceptual, social, and practical skills that have been learned by people in order to function in their everyday lives • Measurement of adaptive behavior has proven difficult because of the relative nature of social adjustment and competence

6. Characteristics of Students with MR • Mild MR • Usually not identified until school age • Most students master many academic skills • Most able to learn job skills well enough to support themselves independently or semi-independently • Moderate MR • Most show significant delays in development during the preschool years • As they grow older the discrepancies in age-related adaptive and intellectual skills widens • Severe MR • Usually identified at birth • Most have significant central nervous system damage • Likely to have health care problems that require intensive supports

7. Characteristics of Students with MR (cont.) • Cognitive functioning • Memory • Learning rate • Attention • Generalization and Maintenance of Learned Skills • Motivation • Adaptive behavior • Self-care and daily living skills • Social development • Behavioral excesses and challenging behavior

8. Prevalence and Causes Prevalence • During the 2005–2006 school year, approximately 0.81% of the total school enrollment received special education services in the MR category and 9.6% of the total school-age population Causes • More than 350 causes of MR have been identified

9. Biological Causes • Prenatal causes include: • Down syndrome • Fetal alcohol spectrum disorders • Fragile X syndrome • Klinefelter syndrome • Phenylketonuria • Prader-Willi syndrome • Williams syndrome • Perinatal causes include: • Intrauterine disorders • Neonatal disorders • Postnatal causes include: • Head injuries • Infections • Degenerative disorders • Malnutrition

10. Environmental Causes • Minimal opportunities to develop early language • Child abuse and neglect • Chronic social or sensory deprivation

11. Prevention • The biggest single preventive strike against MR was the development of the rubella vaccine in 1962 • Toxic exposure through maternal substance abuse and environmental pollutants are two major causes of preventable MR that can be combated with education and training • Advances in medical science have enabled doctors to identify certain genetic influences • Although early identification and intensive educational services to high-risk infants show promise, there is still no widely used technique to decrease the incidence of MR caused by psychosocial disadvantage

12. Educational Approaches Curriculum Goals • Functional curriculum • A functional curriculum will maximize a student’s independence, self-direction, and enjoyment in school, home, community, and work environments • Life skills • Skills that will help the student transition into adult life in the community • Self-determination • Self-determined learners set goals, plan and implement a course of action, evaluate their performance, and make adjustments in what they are doing to reach their goals

13. Instructional Methods • Explicit and systematic instruction • Task analysis • Active student response • Systematic feedback provided by the teacher • Transfer of stimulus control from prompts to task • Generalization and maintenance • Direct and frequent measurement of student performance

14. Educational Placement Alternatives • During the 2005–2006 school year, 14.1% of students with mental retardation were educated in the general education classroom • 29.1% were served in resource room programs • 50.2% were served in separate classes • 6.7% of students with mental retardation are educated in separate schools, residential facilities, or home/hospital environments