Ch 15 Learning Disabilities Flashcards
Definition of LD
unexpected under achievement in academics
arise in childhood
neurobiologically based, developmental
occurs on a continuum, not discrete, dichotomous
Types of LD
Reading disability
Math disability
Written expression disability
NLD that is common in which communities
Turner syndrome
22q11.2 deletion
congenital hydrocephalus
T or F? individuals may grow into their deficits
true
learning deficits may not fully manifest until a later age
% of people with LD
15-20
% of students with LD and need special education in school
13-14% (> 8 million)
% of students who have special education are classified as having SLD?
50%
Cutoff percentiles for LD diagnoses
25%ile (low achieving)
10%ile (extremely low achieving)
% of students with a primary LD have reading and language processing related LD
85%
male to female ratio with LD
1.5x more likely for males
heritability for reading LD
0.3-0.9
heritability for math LD
0.5-0.8
43%
LD is a developmental lag or functional deficit?
functional deficit that persists over time despite intervention efforts
do not spontaneously remit or normalize with time or age (does not grow out of it)
How does Anxiety amplify academic difficulties with LD?
interaction between limbic and frontal systems
anxiety floods frontal systems with excessive dopamine
pushes the system to impairing side of the inverted U shaped curve
Diagnosis of LD - 4 models
Aptitude achievement discrepancy model
Low achievement model
Intraindividual differences model
RTI model
Problems with RTI
no research support for adults
little consensus about how to define inadequate response to appropriate instruction
how to ensure fidelity to implement tiers of intervention
DSM impairment in Reading specifiers
Word reading accuracy
Reading rate or fluency
Reading comprehension
how many genes linked to dyslexia?
13 candidate genes
- 4 of them identified in speech and language d/o
children with genetic risk for development of dyslexia display differences in brain response and orientation to speech sounds as early as
a few days to 6 mos of age
postmortem studies of pts with dyslexia showed
- unexpected symmetry of the planum temporale, polymicrogyria of the L planum temporale, cortical dysplasia in L hemisphere
- L occipitotemporal cortex, middle part of left fusiform gyrus (rapid processing of words - visual word form area)
- alterations in structure (gray and white matter volume) in L hemisphere and R cerebellum
- difference in white matter microstructure in L
- underactivation in Wernicke’s area, angular gyrus, striate cortex
- over activation in inferior frontal gyrus
neural signature of dyslexia
overactivation in inferior frontal gyrus
underactivation in Wernicke’s area, angular gyrus, striate cortex
% of school aged children with Reading disability
10-15%
SES accounts for what % of variance in reading outcomes
10%
Co-occurring conditions in with dyslexia
55% of children with dyslexia have oral language deficits
50% of children with language difficulties have deficient reading
55% have math disability
25-40% have ADHD
deficits in processing speed
Skills needed for reading
phonological awareness - ability to understand words are comprised of speech sounds
Decoding - convert letters into sounds and combines them to form a recognizable word
Sight reading - retrieves or recognizes words from sight
Prediction - uses context, linguistic, background knowledge and memory to text to guess meaning of unknown words (top down skill)
Automaticity (RAN)
strongly predictive of reading, independent of phonological awareness
Double deficit model of Reading disability
2 single deficit subtypes of RD with more limited reading deficits (RAN and phonological awareness)
1 double deficit subtype has more pervasive and severe deficit
poor reading fluency is observed only in people with word recognition difficulties. T or F
False. people with ok word recognition may also have poor reading fluency
Reading comprehension is dependent on
word recognition and fluency - orthographic (visual word form) - morphologic (word meaning) oral language skills (Expressive/receptive vocab) attention and EF
% of students with RD have late emerging reading disability
40% (not evident until at least 3rd grade)
What is fourth grade slump?
reading deficits not shown till after 3rd grade
transition from learning to read to reading to learn
associated with ADHD
Effective reading interventions
small group instruction
repeated reading for reading fluency
intrinsic motivation to increase interest
explicit instruction of comprehension strategies
using different media
training in morphological awareness (i.e. breaking down words into meanings, prefix, roots)
Non evidence based reading interventions
Vision therapy
Fast For Word
Math disability
Number sense
memorization of arithmetic facts
accurate or fluent calculation
accurate math reasoning
Subtype of math disability
semantic memory
procedural error
visuospatial
MD - Semantic memory subtype
deficient, inaccurate, inconsistent arithmetic fact retrieval
MD - procedural memory subtype
use of developmentally immature procedures or errors in the execution of procedures
MD - visuospatial subtype
misalignment of numbers or place value errors in decimals
adult lesion data, not validated in children
Neuropathology of MD
posterior parietal cortex for math processing
intraparietal sulcus, supramarginal gyrus, angular gyrus
younger kids who just started learning math have greater prefrontal activation
adolescents and adults decrease dependence on working memory and attentional resources mediated by prefrontal gyrus
prevalence of M LD
20%
% of 4th graders and 8th graders who are below basic level in math?
20% of 4th graders
30% of 8th graders
% of 4th graders and 8th graders who are below basic level in Reading?
32% of 4th graders
24% of 8th graders
co-occurring conditions with MD
reading LD
automaticity, phonological awareness for math computation
working memory
EF, attention, VS
Neurodevelopmental disorders associated with MLD
Turner syndrome Fragile X Congenital hydrocephalus Neurofibromatosis type I Spina bifida Congenital hypothyroidism 22q deletion syndrome Williams syndrome Preterm, low BW
Difference between math and reading
math achievement is cumulative throughout and beyond elementary school years
Skills required in math acquistion
domain specific skills:
numerosity (understanding and recognizing concept of quantity)
- symbolic comparison, non symbolic comparison number line estimation, procedural counting, conceptual counting
doman general skills
- language, phon awareless, VS, nonverbal reasoning, working memory, processing speed, attention, EF
Teaching kids math problem solving can translate into improved math calculations
True but not the other way around
DSM 5 impairment in written expression categories
spelling
grammar and punctuation
clarity or organization of written expression
neuropathology
limited research
some alterations in white matter microstructure in L hemisphere
% of people with written expression disability
7-15%
Male to female ratio in disability in writing
3:1
co-occuring % between reading and writing disability
75%
% of 4th and 8th grader performing at below basic writing level
20% 4th grader
21% 8th grader
Dysgraphia
deficits in automatic letter writing, orthographic coding, finger sequencing
Treatment of written expression difficulties
self regulated strategy development to help with self regulation strategies to improve writing process
systematic and explicit instruction on transcription skills
development of oral language skills
