Intellectual Disability
Intellectual Disability
“Intellectual disability” (mental retardation)
refers to a particular state of functioning that
begins prior to age 18, characterized by
significant limitations in both
intellectual functioning
and
adaptive behavior
(AAMR, 2002).
Multi-factorial approach to etiology
• Biomedical: genetic or nutrition
• Social: fanily interaction, stimulation…
• Behavioural: potentially causal behaviours
such as dangerous activities or maternal
substance abuse
• Educational: availabilioty of educational
supports that promote motor development
and development of adaptive skills
Co-morbidity
• Down syndrome
• Autism
• Global developmental delay
Recommendations
1. Understand the referral question (i.e.
questions that need answers at the end of
the examination)
2. Use multiple sources of information
3. Use disorder specific knowledge
4. Use appropriate assessment strategies
5. Use multiple assessment approach:
Norm referenced, interviews, observations &
informal assessment
• Collaborate with other professionals
• Provide appropriate feedback
<Measuring adaptive functioning >
Vineland Adaptive Behaviour Scales – II
• 0 – 90 years
• Survey interview, expanded survey interview,
parent/caregiver rating form, teacher rating
form (3 years – 21-11 months)
• Communication domain
• Daily living skills domain
• Socialisation skills domain
• Motor domain
• Maladaptive behaviour
Intellectual assessment
• Weschler Preschool & Primary Scales of
Intelligence (WPPSI)
• Weschler Scales for Children (WISC III/ IV)
WISC 3
Replaced
by WISC 4
in 2003.
Currently
no Czech
norms are
available
for WISC 4.
WISC 3
• Intended for children ages 6 to
16 and 11 months.
• Composed of VERBAL and
PERFORMANCE scale
WISC 3
• Verbal Scale
– Five Mandatory Subtests
• Information
• Similarities
• Arithmetic
• Vocabulary
• Comprehension
– One Supplementary Test
• Digit Span
– This test can be substituted for one of the other tests if and only if
the data from a mandatory subtest is missing or invalidated.
Performance Scale
– Five Mandatory Subtests
• Picture Completion
• Picture Arrangement
• Block Design
• Object Assembly
• Coding
– Two Supplementary Subtests
• Mazes
• Symbol Search
– Mazes subtest can be substituted for any of the
mandatory subtest if the data is missing or
invalidated.
– Symbol Search can only be substituted for the
Coding subtest.
Criticisms of Weschler
• Does not measure other intelligences
- i.e. Gardner’s multiple intelligences
WISC 4
WISC 4
TABLE 13.1. Subtests of the Wechsler Intelligence Scales for
Children—4th Edition (WISC-IV)
Organized by Index
Index Subtest
Verbal Comprehension
• Comprehension: The student is required to answer orally
presented questions pertaining to social rules or problems.
• Similarities: The student is required to explain the similarities
between oral word pairs.
• Vocabulary: The student is required to name pictures or
provide definitions for words.
• Information (Supplemental): The student is required to
answer factual questions of learned content.
• Word Reasoning (Supplemental): The student is required to
identify a common concept based on successive verbal clues.
Perceptual Reasoning
• Block Design: The student is required to rearrange a set of
blocks to match visual patterns presented on a card (timed).
• Picture Concepts: The student is required to choose pictures
from rows in an array to form a group with common
characteristics.
• Matrix Reasoning: The student is required to draw visual
analogies and respond to multiple-choice questions.
•Picture Completion (Supplemental): The student is required to
identify missing element of picture of common object or
setting (timed).
Processing Speed
• Coding: The student is required visually to match
numbers with corresponding
symbols and record appropriate symbols under numbers
(timed).
• Symbol Search: The student is required visually to scan
an array and mark target
symbols (timed).
• Cancellation (Supplemental): The student is required to
scan both a random and a
nonrandom arrangement of pictures and mark target
pictures (timed).
Working Memory
• Digit Span: The student is required to repeat orally
presented numbers forwards and
backwards.
• Letter-Number Sequencing: The student is required to
recode orally presented letter–
number combinations, stating the numbers in ascending
order and the letters in
alphabetic order.
• Arithmetic (Supplemental): The student is required to
solve mentally and express
orally the answer to orally presented arithmetic
problems.
Non-verbal tests
• Raven’s Progressive Matrices
• Leiter International Performance Scale (LeiterR,
Roid & Miller, 1997)
Leiter- R
• Visualisation & Reasoning Battery
• Attention & Memory Battery
• For ages 2- 20
Raven’s Progressive Matrices
Coloured Progressive Matrices
• 36 items
• For children aged: 5 – 11
• For elderly with dementia
• For those with mental retardation
• Measures fluid intelligence
Measures fluid intelligence (versus crystallised)
Previous studies show a strong correlation between
test performance and level of education (Smits et al,
1997), intellectual and visual spatial capacities
(Raven, 1984), and dementia (Gainotti, Parlato,
Monteleone & Carlomagno, 1992).