Chapter 4 Intellectual Disabilities

Definitions of Mental Retardation IDEA definition 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

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.

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

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

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

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

Prevalence and Causes Prevalence Causes 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

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

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

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

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

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

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