Week 11: Intellectual Disability Flashcards
Measuring Intelligence and IQ
First IQ test developed in France by Alfred Binet and Theophile
Simon
French government commissioned them to develop a way to
identify school children who might need special help in school
Developed the Stanford-Binet scale which was the first intelligence
test
In the early 20th century, in Canada, the United States, and Western
Europe, many wealthy and/or influential people subscribed to the
pseudoscience of eugenics
IQ testing was seen by eugenicists as a way to identify people who
they thought should not be allowed to have children
Subsequent development of IQ tests was racist, testing culturally based knowledge and test-taking proficiency (if you did not have access to the information, you did poorly)_
During this time, people identified as having lower intellectual
functioning were put in institutions and sterilized without their
consent
More likely to be Black, Indigenous, and poor
IQ and DSM 5
In DSM-5, intellectual disability is defined by adaptive functioning,
rather than strictly by intellectual functioning and IQ
Note that is a change from DSM-IV
When considering treatment, focus is on integration and building
strengths and independence
A series of tasks designed to assess different types of intelligence
Weschler Intelligence Scale for Children (WISC)
Children aged 6 to 17 years
Also a preschool version
Current tests and criticism
A series of tasks designed to assess different types of intelligence
Weschler Intelligence Scale for Children (WISC)
Children aged 6 to 17 years
Also a preschool version
Continued criticisms of IQ Tests
Test knowledge associated with the cultural majority
Focus on speed of processing
Core Features of Intellectual
Disability: DSM-5
(1) Deficits in intellectual functioning including reasoning, problem
solving, planning, abstract thinking, judgment as confirmed by
both clinical assessment and individualized, standardized
intelligence testing
NOT A SET IQ NUMBER
(2) Deficits in adaptive functioning that result in failure to meet
developmental and sociocultural standards for personal
independence and social responsibility; functioning is limited in
one or more activities of daily life such as communication, social
participation, and independent living, across multiple
environments
e.g. can they dress themselves?
Onset during developmental period
Level of Severity Based on
Adaptive Functioning
Mild
Moderate
Severe
Profound
Not based on IQ scores
Mild
Mild
Applies to about 85% of persons with ID
Typically not identified until elementary school years (might need support here)
Children from lower SES families are more likely to have mild ID
Moderate
Moderate
Applies to about 10% of persons with ID
Usually identified during preschool years
Applies to many people with Down syndrome
Severe
Severe
applies to about 3%-4% of persons with ID
often associated with clear organic cause
usually identified at a very young age
-Relationships can develop
-need help with daily life
Profound
Profound
applies to about 1%-2% of persons with ID
usually identified in infancy
almost always associated with clear organic cause and often co-occurs
with severe medical conditions
Prevalence
Prevalence
Community prevalence estimates range from 1% to 3%
Cultural and contextual differences
More prevalent in lower SES groups
Differences only apparent for less severe ID
Gender differences
Slightly more males than females (many organic conditions which cause this are x-linked)
Etiology
Organic
includes chromosome abnormalities, single gene conditions, and
neurobiological influences
tend to be moderate, severe, and profound
Prevalence comparable across SES groups
Cultural / Familial
Does not have a clear cause
Includes family history of intellectual disability, economic deprivation,
inadequate child care, poor nutrition, and parental psychopathology
Tend to be mild cases (most cases!)
Higher rates in lower SES families (worse nutrition)
Specific Organic Syndromes
Chromosomal abnormalities
Most common cause of severe ID
Down syndrome (chromosome 21, most cases are random events, chance mutations)
Prader-Willi and Angelman (chromosome 15, most cases are random
events)
Fragile-X syndrome (X chromosome, inherited)
Single-gene problems
Phenylketonuria (PKU; inherited)
Cannot metabolize amino acid phenylalanine, rising levels are toxic and
impact intellectual development
Neurobiological injury
Prenatal (e.g., Fetal Alcohol Syndrome)
Perinatal (e.g., anoxia at birth)
Postnatal (e.g., head injury)
Summary of Causes
Genetic factors
General heritability of intelligence is about 50%
Rare conditions associated with ID also inherited
Neurobiological influences
Prenatal, perinatal, and postnatal injury
Environmental influences
Heritability estimates decrease when SES is lower
Lower SES environments, environmental factors explain the majority of the variability in IQ
Intelligence is all inheritable if yo have money, if not it will be pulled downwards
Deprivation of physical and emotional care, social stimulation, and early
learning environment
Prevention
Prenatal care Reduce prenatal neurobiological injury Increase gestation time (carry to full term) Plan for uncomplicated delivery Early childhood care and education Safe and stimulating environments Safe Lead paint (common in poorer housing) Stimulating Educational programs Major focus on speech and communication Early intervention (preschool) optimal Educational enrichment for low-SES youth
Educational Enrichment
How many words per hour are addressed to a toddler who has
parents with advanced degrees? 2153
Toddler with parents who have not gone to university? 1251
Toddler with parents who are receiving social assistance? 616
Huge difference
14 hours a day
7 days a week
52 weeks in a year
4 years
In fact, kids of the professional parents use more words than PARENTS on welfare
