Chapter 4 Mental Retardation

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Chapter 4Mental Retardation
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Definitions of Mental Retardation

• AAMRs 1983 definition in IDEA
• Significantly subaverage intellectual functioning
• Deficits in adaptive behavior
• Manifested during the developmental period
• AAMRs new definition based on needed supports
• Significant limitations in both intellectual
  functioning and conceptual, social, and practical
  adaptive skills the disability originates before
  age 18
• Intensity of supports
• Intermittent - As needed, short-term supports
• Limited - Consistent support for limited time
• Extensive - Consistent support in some settings
• Pervasive - Consistent, high intensity support in
  most settings

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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

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Normal Curve
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Assessing Adaptive Behavior

• Adaptive behavior is the effectiveness or degree
  with which the individual meets the standards of
  personal independence and social responsibility
  expected of his age and social group
• Measurement of adaptive behavior has proven
  difficult because of the relative nature of
  social adjustment and competence
• Adaptive Behavior Scales (ABS-S) Observational
  scale. Part 1 independent functioning Part
  2-Maladaptive behavior
• Vineland Informant assessment
• Scales of Independent Behavior-Provides a
  comprehensive assessment of 14 areas of adaptive
  behavior and 8 areas of problem behavior

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Prevalence and Causes

• Prevalence
• During the 2000-2001 school year, approximately
  1 of the total school enrollment received
  special education services in the MR category
• Mild MR cases make up about 85 of all persons
  with MR
• Causes
• More than 750 causes of MR have been identified
• For approximately 50 of mild MR cases and 30 of
  severe MR, the cause is unknown

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Biological Causes

• Prenatal causes include
• Chromosomal disorders
• Inborn errors of metabolism
• Developmental disorders
• Toxic exposure through maternal substance abuse
• Perinatal causes include
• Intrauterine disorders
• Neonatal disorders
• Postnatal causes include
• Head injuries
• Infections
• Degenerative disorders
• Malnutrition

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Chromosomal and Genetic Causes

• Tuberous sclerosis Tumors in nervous system
• Phenylketonuria (PKU) inability to metabolize
  enzyme phenylalanine
• Hurler Syndrome Inability to break down various
  carbohydrates
• Tay-Sachs disease abnormal buildup of lipids
  within body tissue
• Fragile X Triplet, repeat mutation on the X
  chromosome
• Down Syndrome -21st set of chromosome is a triplet

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Environmental Causes

• Toxoplasmosis Protozoic infection
• Rubella German measles infection
• Radiation Exposure to radiation in utero
• Malnutrition Pre- and post-natal lack of
  adequate nutrition
• Drug abuse exposure in utero
• Blood type incompatibility
• Mosquito bite - encephalitis
• Anoxia loss of oxygen (umbilical cord around
  neck)

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Environmental Causes
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• Biggest preventive strike was the development of
  the rubella vaccine

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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

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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

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Wild Boy 1800

• Dr. Jean Marc Itard was the first to develop a
  individualized educational procedure. He
  developed a student centered approach.
• Wild Child
• Itard, J.M.G. (1962). The wild boy of Aveyron.
  (G. Humphrey M. Humphrey, Trans.). New York
  Appleton-Century-Crofts. (Original works
  published 1801 and 1806).

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Educational Approaches

• Curriculum Goals
• Functional curriculum
• A functional curriculum will maximize a students
  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

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Characteristics of Effective Instruction

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

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Educational Placement Alternatives

• Some children with MR attend special schools
• Most are educated in their neighborhood schools
• Special classes
• Regular class with support
• Resource room
• The extent to which a student with MR should be
  included in the regular classroom should be
  determined by the students individual needs

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Current Issues and Future Trends

• Some concerns of the current definition of MR
  include
• IQ testing will remain the primary means of
  assessment
• Adaptive skills cannot be reliably measured with
  current assessment methods
• The levels of need supports are too subjective
• Classification will remain essentially unchanged
  in practice
• Acceptance and membership
• An especially important and continuing challenge
  is moving beyond the physical integration of
  persons with MR in society to acceptance and
  membership that comes from holding valued roles