1. Chapter 4 Intellectual Disabilities

2. 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

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 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

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