Ch 13 Intellectual Disability Flashcards
Dx of Intellectual Disability
IQ score 2 SD below the mean (65-75)
deficits in adaptive functioning
onset of sx in childhood or adolescence
severity of ID based on adaptive fx, not IQ scores
IQ scores are less valid in what range?
tail end
neuropathology of ID?
changes in early brain dev such as reduced cerebral volume, diffuse pathology
microcephaly w/ differential volume reduction (e.g. fetal alcohol syndrome)
enlarged head circumference and mild ventricular enlargement (e.g. autism)
changes related to neuronal proliferation, apoptosis, migration, synaptogenesis, dendritic pruning
prevalence of ID
<1%
male to female ratio for ID
1.5 : 1
why are there more males than females with ID
x linked syndromes that cause ID (e.g. fragile X syndrome)
Causes of ID
genetic (e.g. downs syndrome, fragile X, williams syndrome, tay-sachs disease, maple syrup urine disease, prader willi syndrome, angelman syndrome, klinefelter syndrome, tuberous sclerosis)
acquired (e.g. prematurity, low BW, exposure to alcohol, drugs, toxins, TBI, infections, iodine deficiency, stroke, epilepsy, meningitis, whooping cough, anoxia)
most prevalent form of ID?
down’s syndrome
most common familial or inherited form of ID?
fragile X
preventable cause of ID
iodine deficiency causing thyroid hormone deficiency during pregnancy
fetal alcohol syndrome
first line test for children with ID of unknown cause?
chromosome microarray
tests for ID?
fragile X testing, brain MRI
percentage of people with ID in the mild range
85%
Mild ID characteristics
delays in language
fluent speakers in adolescence
academic skills can be acquired up to 6th grade level
immature social interaction
concrete problem solving and language skills
personal care ok, need support for complex daily living
can work jobs that dont require non-conceptual skills
need help making decisions
% of people with moderate ID
10%
Moderate ID characreristics
functional language by adolescence
academic skills up to 2nd grade
need moderate supervision
can establish meaningful relationships w/ family and friends
hard to perceive social cues, limited social judgment
limited decision making skills
can care for basic personal needs with teaching
possible employment with limited conceptual and communication skills
need a lot of support for decision and management
% of people with severe ID
3-4%
Severe ID characteristics
limited language (single words, phrases, use gesture)
poor academic skills (ok with alphabet, simple counting)
need extensive supervision for life, work, recs
depend on family members and others
cannot make decisions
few show maladaptive behavior (e.g. self injury)
% of people with profound ID
1-2%
Profound ID characteristics
can learn single words
no academic skills
need pervasive supervision and support
poor conceptual skills
understand simple instructions or gestures
use non verbal, non symbolic means to express and communicate
enjoy relationship with fam and friends
simple actions with objects regarding job skills
may have physical and sensory impairment
may have maladpative behavior
Angelman syndrome results from
deletion on chromosome 15 contributed by mother
Prader Willi syndrome results from
deletion on the same chromosome contributed by father or by receiving 2 chromosome 15s contributed by mother
Angelman syndrome involves
ID sleep disturbance seizures jerky movements frequent laughter or smiling usually happy demeanor =)
Prader Willi syndrome involves
ID
low muscle tone
short stature
incomplete sexual development
compulsive behaviors
chronic feelings of hunger and excessive eating
more maladaptive behaviors and cognitive impairment in those who have deletion on same chromosome
individuals with ID have shorter lifespan
T or F
T (in their 60s)
scales of dev fx
Bayley scales of infant development
Mullen scales of early Learning
IQ measures
WAIS DAS Kaufman Stanford Binet Leiter International Performance Scales
Adaptive functioning measures
Vineland
ABAS
Scales of independent behavior SIB
intervention programs for ID
ABA
proper nutrition
helmet
vaccination
Risk of ID with aging
down syndrome and Fragile X have declines in IQ with age
Down syndrome people may have AD and die within 8 yrs of AD dx
IQ NP characteristics in people with ID
IQ usually 70 or below
poor attention
slow processing
language varies (Williams syndrome - verbal IQ > non verbal IQ)
Visuospatial common (Williams syndrome spatial cognition poor, ASD and Downs relative strength in visuospatial)
memory varies, but generally weak in Long term memory
EF impaired
sensory motor delays
emotion and personality - impulse control, frustration tolerance, mood, low self esteem
PVT performance in ID
mild ID - rarely fail PVT
use alternate administration if needed
maintain SP at 90% for cutoff scores
% of mild ID people failing PVT
10-13%
psych fx in ID
4-5x mor likely diagnosed with psych problems
Risk factor modification (3 tiers)
Primary tier: prevention by improving nutritional status, immunization, avoiding exposure, education of complications
secondary tier: neonatal screening, med tx, EIP
tertiary tier: education, training, support
maple syrup urine disease
rare genetic d/o
deficiency of particular enzymes to metabolize certain protein amino acids properly (error of metabolism)
how many known genetic causes of ID are there
more than 1000
which two preventable causes of ID are mandated to be screened?
PKU and congenital hypothyroidism
