Chapter 5 Intellectual Disability (Intellectual Developmental Disorder)

What is intellectual disability (ID)?

A condition characterized by significant limitations in mental abilities and impairments in adaptive functioning.

What are the three essential elements defining intellectual disability?

Intellectual limitations, deficits in adaptive skills, and early onset.

How is general intellectual functioning measured?

By an intelligence quotient (IQ) based on standardized intelligence tests.

What is adaptive functioning?

How effectively individuals cope with ordinary life demands and their capability to live independently.

What does the DSM-5 diagnostic criteria for intellectual disability include?

Deficits in intellectual functioning and concurrent deficits in adaptive functioning, evident before age 18.

Why is criterion B of the DSM-5 important?

It excludes individuals who may function well in their surroundings but do not perform well on standard IQ tests.

What is the significance of criterion C in the DSM-5?

It establishes an upper limit for age of onset to rule out mental deficiencies caused by adult-onset conditions.

What IQ score typically indicates intellectual disability?

An IQ score of 70 points or below, which is 2+ standard deviations below the population mean.

What percentage of individuals with ID are classified as having mild severity?

About 85% of persons with ID.

At what age are individuals with mild intellectual disability typically identified?

Usually not until early elementary years.

What percentage of individuals with ID are classified as having moderate severity?

About 10% of persons with ID.

When are individuals with moderate intellectual disability usually identified?

During preschool years, often due to delays in developmental milestones.

What percentage of individuals with ID are classified as having severe severity?

About 3-4% of persons with ID.

What are some characteristics of individuals with severe intellectual disability?

Often associated with organic causes, identified at a young age, and may have mobility or health problems.

What is a common outcome for children with mild intellectual disability?

They can achieve academic skills up to approximately the sixth-grade level and may live successfully in the community with support.

What challenges do children with moderate intellectual disability face?

They may communicate using single words and gestures and require assistance for daily routines.

What is the impact of early stimulation on children with developmental delays?

It helps them build on existing strengths and can influence intellectual ability significantly.

What is the correlation between IQ measured in infancy and later IQ scores?

There is virtually no correlation for infants, but a high correlation by age 4.

How do social and economic disparities affect the identification of intellectual disabilities?

They may lead to overrepresentation of minority group members in diagnoses of ID.

What is the role of experience in assessing adaptive skills?

A child's adaptive skills can be influenced by their experiences and opportunities, affecting their performance on tests.

What are some examples of adaptive behavior skills?

Using public transportation, making simple purchases, and performing self-care tasks.

What is the significance of a supportive environment for individuals with ID?

A healthy, stimulating environment can enhance learning and development opportunities.

What are some common characteristics of children with Down syndrome regarding intellectual disability?

They often have moderate intellectual disability and benefit from vocational training.

What is the expected academic progression for individuals with severe intellectual disability?

They may master basic self-care skills and perform simple tasks in closely supervised settings.

What is the severity level of profound intellectual disability?

Profound intellectual disability affects about 1-2% of persons with ID.

At what stage is profound intellectual disability typically identified?

It is identified in infancy due to marked delays in development and biological anomalies.

What are some characteristics of individuals with profound intellectual disability?

They learn only rudimentary communication skills and require intensive training for eating, grooming, toileting, and dressing behaviors.

What type of care do individuals with profound intellectual disability require?

They require lifelong care and assistance.

What is the estimated prevalence of intellectual disability in the population?

Approximately 1-3%, depending on the cutoff used.

What factors contribute to variations in estimates of intellectual disability prevalence?

Variations arise from IQ measurement problems, different definitions of ID, and varying study designs.

What is the gender ratio among those with mild intellectual disability?

There are twice as many males as females among those with mild cases.

What might explain the gender differences in the prevalence of intellectual disability?

Gender differences may be an artifact of identification and referral patterns rather than true differences.

What is suspected to cause a true male excess in intellectual disability?

The occurrence of X-linked genetic disorders, which affect males more often than females.

In which socioeconomic groups is mild intellectual disability more prevalent?

It is more prevalent among children of lower socioeconomic status (SES) and children from minority groups.

How are more severe levels of intellectual disability identified across different groups?

More severe levels are identified almost equally across different racial and economic groups.

What is the developmental-versus-difference controversy in intellectual disability?

It questions whether all children progress through the same developmental milestones in a similar sequence but at different rates, regardless of intellectual impairments.

What does the similar sequence hypothesis propose about cognitive development in children?

Children pass through stages of cognitive development in an identical order, differing only in their rate and upper limit of development.

What is the similar structure hypothesis in relation to children with intellectual disabilities?

It suggests that children with intellectual disability demonstrate the same behaviors and underlying processes as typically developing children at the same cognitive functioning level.

What does the developmental position reject regarding children with intellectual disabilities?

It rejects the notion of a specific deficit or difference, emphasizing that these children traverse developmental stages more slowly and attain a lower developmental ceiling.

What is the difference viewpoint in the developmental versus difference controversy?

It posits that cognitive development of children with intellectual disabilities differs qualitatively from that of children without intellectual disabilities, not just in rate and upper limit.

What are the two groups in the Two-Group Approach to intellectual disability?

The organic group, which has a clear biological basis, and the cultural-familial group, which lacks a clear organic basis.

What characterizes familial versus organic intellectual disability?

Familial ID is inherited and generally follows developmental stages in an invariant order, while organic ID often has specific deficit areas affecting performance.

How do children with familial intellectual disabilities perform compared to their mental-age-matched peers?

They show slight deficits in memory and information processing, possibly due to motivation issues with repetitive tasks.

What are common characteristics of children with organic intellectual disabilities?

They often have specific deficits that cause poorer performance compared to mental-age-matched peers, including in expressive language.

What impact does motivation have on children with mild intellectual disabilities?

They may experience feelings of helplessness and frustration, leading to decreased motivation to tackle new demands.

How can children with mild intellectual disabilities succeed in learning environments?

With stimulating environments and caregiver support, they can stay on task and develop goal-directed behavior.

What does the slowing and stability hypothesis suggest about children with Down syndrome?

It suggests they may alternate between periods of gains in functioning and periods of little or no advance, with potential IQ plateaus during middle childhood.

How does language development typically progress in children with Down syndrome?

They experience considerable delay in expressive language development, with expressive language being weaker than receptive language.

What are common emotional and behavioral problems in children with intellectual disabilities?

They experience higher rates of impulse control disorders, anxiety disorders, and mood disorders, often due to limited communication skills and stressors.

What is the prevalence of self-injurious behavior (SIB) among individuals with intellectual disabilities?

SIB affects about 8% of persons across all ages and levels of ID and can be life-threatening.

What are the four major categories of risk factors for intellectual disabilities?

Biomedical, social, behavioral, and educational.

What prenatal factors can contribute to intellectual disabilities?

Genetic disorders and accidents in the womb.

How can the prenatal environment influence IQ?

Prenatal influences such as nutrition and exposure to toxins may significantly affect cognitive functioning.

What is the impact of adopting children from disadvantaged backgrounds into privileged homes?

They tend to have higher IQ scores, stronger self-esteem, and fewer acts of delinquency compared to siblings raised by disadvantaged biological parents.

What role does maternal nutrition play in the cognitive functioning of children?

Improving maternal nutrition and reducing prenatal exposure to toxins can enhance children's intellectual and cognitive functioning.

What is the most common cause of Down syndrome?

An additional chromosome on the 21st pair (trisomy 21), with increased risk associated with maternal age.

List some physical features of Down syndrome.

Small skull, large tongue, almond-shaped eyes, flat nasal bridge, short crooked fifth finger, broad square hands with a simian crease.

What chromosomal abnormality is associated with Fragile-X syndrome?

A pinched area on the X chromosome.

What are common physical features of Fragile-X syndrome?

Large forehead, prominent jaw, low protruding ears.

What range of intelligence is typically seen in individuals with Fragile-X syndrome?

Mild to moderate intellectual disability; some may have normal intelligence.

What are some social and communication patterns observed in males with Fragile-X syndrome?

Marked shyness, poor eye contact, and significant delays in cognitive and communication development.

What are the characteristics of Prader-Willi syndrome?

Short stature, intellectual disability, incomplete sexual development, low muscle tone, and an involuntary urge to eat constantly.

What are the symptoms of Angelman syndrome?

Moderate to severe intellectual disability, ataxia, jerky movements, hand flapping, seizures, and distinctive facial features.

What is phenylketonuria (PKU) and its effects?

A lack of liver enzymes to metabolize phenylalanine, leading to brain damage, intellectual disability, and other health issues.

What are some adverse biological conditions that can influence intellectual disabilities?

Infections, traumas, and accidental poisonings during infancy and childhood.

What is Fetal Alcohol Spectrum Disorder (FASD)?

A range of effects caused by alcohol exposure during pregnancy, including intellectual functioning issues and physical abnormalities.

What percentage of intellectual disabilities are attributed to environmental influences and mental disorders?

15-20%.

What factors contribute to a child's overall adjustment in cases of intellectual disability?

Parental participation, family resources, social supports, level of intellectual functioning, and specific deficits.

What is the role of early intervention in treating intellectual disabilities?

To enhance intellectual and social skills through supplemental educational experiences before school.

What is the focus of behavioral approaches in treating children with intellectual disabilities?

To control or redirect negative behaviors while promoting language and social skills.

Describe the language training method used for Vanessa.

Shaping, where she was taught to imitate sounds and words progressively with praise and food rewards.

What are family-oriented strategies in supporting families of children with intellectual disabilities?

Providing support and guidance to help families cope with the demands of raising a child with ID.

What is the inclusion movement in education for children with disabilities?

Integrating individuals with disabilities into regular classroom settings with adapted curriculum.

What are the potential preventive measures for intellectual disabilities related to fetal alcohol syndrome?

Caution against alcohol, tobacco, drugs, and caffeine during pregnancy.

What is the significance of prenatal screening?

To determine if a fetus has a genetic abnormality through methods like ultrasound and amniocentesis.

What are the characteristics of children with Angelman syndrome?

Moderate to severe intellectual disability, ataxia, seizures, and distinctive facial features.

What is the treatment approach for PKU?

A restricted diet to prevent the accumulation of phenylalanine.

What is the estimated occurrence of Fetal Alcohol Syndrome?

1/2 to 2 per 1000 live births.

What are some behaviors associated with Fragile-X syndrome?

Autism-like behaviors such as hand flapping, biting, and walking on toes.

How can social support and community resources impact families with children who have ID?

They can enhance coping abilities and provide necessary assistance.