Intellectual Disability (Exam 2)

AAIDD Approach

Definition of ID: significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social, and practical adaptive skills, originates before 18.

Intellectual abilities, adaptive behavior, health, participation, roles, and interactions, context

Treatment based solely on individual

DSM approach

definition of ID: neurodevelopmental disorder that begins in childhood, intellectual and adaptive limitations

specifies severity of ID based on adaptive functioning, from mild to profound

ID Severity

Mild- 85%, can live independently with minimal support

moderate- 10%, independent living may be achieved with moderate levels of support

severe- 3.5%, requires daily assistance with self-care activities and safety supervision

profound- 1.5%, requires 24-hour care

measured intelligence

measured by the presentation of tasks that tap both general and specific abilities

Binet and Simon (1905)

First intelligence scale, consisting of tasks that average students of various ages passed. When evaluated on scale, children were given a mental age

Lewis Terman

adopted idea of intelligence quotient (IQ)- ratio of an individual’s mental age to chronological age, multiplied by 100

Adaptive behavior

what people do to take care of themselves and to relate to others in daily living, multidimensional

conceptual: memory, language, reading, reasoning

social: awareness of others’ thoughts and feelings, self-esteem, social responsibility, friendship abilities

practical: activities and personal care of daily living, use of money, safety, occupational skills

Mild ID Description

conceptual: no obvious early differences, difficulties in learning core school subjects and executive functioning skills

social: may be more concrete or immature than expected for age, difficulties in perceiving social cues and regulation emotions

practical: may function age-appropriately in personal care but need guidance and assistance in daily living tasks

Moderate ID Description

conceptual: delays in language and pre-academic skills, unlikely to progress beyond elementary-level mastery of academic skills, support required for tasks of daily life and work

social: usually develops communication skills but may be much less complex than that of peers, may establish friendships and romantic relationships but be limited by communication or social deficits

practical: can care for age-appropriate personal needs with extended period of teaching and time, can benefit from occupational training and support to perform unskilled or semiskilled work

Severe ID Description

conceptual: limited conceptual skills, little understanding of written language or concepts involving numbers, quantity, time, and money

social: spoken language limited in vocabulary and grammar; may understand simple speech and gestures; communication aids may be helpful

practical: requires support for all activities of daily living, can adapt to community living with family or in group homes, maladaptive behavior may be present in significant minority

Profound ID Description

conceptual: limited to understanding objects and physical world, some skills may be acquired, co-occurring sensory and physical impairments likely present

social: limited understanding and use of communication in speech or gesture, enjoys relationships with well-known family members, caretakers, and familiar others

practical: dependent on others for all aspects of daily physical care, health, and safety, may do simple supervised tasks, requires structure and constant supervision for optimal development

co-occurring disorders

ADHD, ASD, anxiety, oppositional/ conduct problems, OCD, schizophrenia

epidemiology

fallen from 3% to 1%

more in males

etiology

abnormal brain development or injury to brain

Organic Group

shows a clear organic cause of ID, more prevalent at moderate, severe, and profound levels, near equal rates across all ethnic and SES levels, associated with other physical disabilities

Cultural-Familial Group

no obvious cause of intellectual disability; sometimes another family member has ID, more prevalent in mild ID, higher rates within minority groups and low-SES groups, few associated physical or medical disabilities

behavioral phenotypes

a specific disorder predisposes individuals to certain behaviors

Down Syndrome

most common single disorder of ID, trisomy 21

chromosome 21 appears in triplet instead of pair in 95% of cases

occurs randomly, traced to advanced maternal age

reduced brain size and number and density of neurons, abnormal dendrites

80% experience dementia by 65

related to heart defects, respiratory anomalies, gastro problems, visual difficulties

life expectancy: 60 years old

Fragile X Syndrome

most common inherited form of ID, caused by abnormal gene expression in FMR1 gene, inherited in X linked pattern, males more frequently affected

disruption in proteins involved in regulating the development of synapses and other processes important in early brain development, cerebellum, frontal, and parietal lobes

Almost all males have ID, 1/3 of females

Williams Syndrome

rare disorder resulting from a random mutation involving small deletions of several genes on chromosome 7. Cardiac and kidney problems, mild to moderate ID.

Reduced and enlarged brain regions, abnormal brain activation during tasks involving response inhibition, visual processing, auditory processing of music and noise. Reduced amygdala activation in response to angry and fearful faces

Prader-Willi Syndrome

Abnormality in long arm of chromosome 15, in 70% of cases there’s a deletion in these genes, the rest, both chromosome 15 are inherited from mother

infants display low muscle tone, lethargy, difficulty feeding, excessive eating, and hoarding, OCD

Infant and toddler tests

most popular is Bayley scales, covers ages 1-42 months including scales for cognition, language, and motor development. Performance is referred to as developmental quotient

Stanford- Binet Intelligence Scales

Assesses fluid reasoning, knowledge, quantitative reasoning, visual-spatial processing, and working memory, full-scale IQ can be obtained, for 2–85-year-olds

Wechsler Tests

most widely used intelligence test in ages 6-16

includes verbal comprehension, visual-spatial, fluid reasoning, working memory, and processing speed, full-scale IQ derived

Kaufman Battery

3-18 yrs, five scales of cognitive and processing ability: sequential processing, simultaneous processing, planning, learning, knowledge

results in global intelligence score

Flynn Effect

avg. IQ of humans increases over time

Treatment

educational supports, inclusion, normalization, behavioral intervention, enhancing adaptive behavior, reducing challenging behavior, stimulants, antipsychotic medication, psychotherapy