Developmental disorders Flashcards
(44 cards)
list aspects that create environment
diet, maternal drug abuse, orthnography, social envionment, teaching style, deprivation, trauma
what % of people are affected by developmental dyslexia?
3-6%
talk about dyslexia prevelance
cross-cultures
across lifespan
more males than females.
what does dyslexia inhibit?
reading achievement is Substantially below that expected given the person’s
chronological age, measured intelligence and age-appropriate
education
Significantly interferes with academic achievement or
activities of daily living that require reading skills
talk about causation of dyslexia
is not explained by a sensory deficit.
talk about memory deficits in dyslexia
verbal short term memory deficits- norm memory for visual info poor memory for verbal info.
what deficit do dyslexic patients have regarding naming objects
Rapid Automated naming deficits- naming well known objects at speed
Denckla & Rudel 1976
talk abut dyslexia and phonological awareness deficits
- Syllable-tapping task: tap out the number of syllables (or beats) that youcan hear in the word (cat=1; banana=3)
- Onset-rime (crust-cross) & initial-final phoneme (coat-goat) judgment tasks: both names were pronounced by the experimenter, and the subjects were asked to decide whether the names had any sounds in common.
- Phoneme-tapping task: tap out the number of sounds that they could hear (cat=3)
deficits in all
discuss visual deficits in dyslexics
Cornelissen et al.
dyslexics have higher motion coherence thresholds than controls
Describe Buck’s phonological account to dyslexia
DIFFICULTY ANALYZING THE SOUND STRUCTURE OF LANGUAGE. this leads to a failure to learn systematic relationship between spellings and sounds. failure to master spelling sound correspondences is a primary source of the word recognition problems.
-innacurate representations not difficulty analysing.
what is a flaw with Buck’s phonological account to dyslexia?
a very specific account in that the problems are constrained to the domain of language
what is there debate about regarding dyslexia?
how different phonological functions/ issues are related (e.g. rapid naming vs decoding)
discuss dyslexia in terms of a temporal processing deficit
- have difficulties percieving short streams of sound
- difficulty perceiving tones of sound–> problems representing speech at a fine-grained level.
- correlations between rate of auditory processing and reading errors.
discuss dyslexia in terms of a magnocellular deficit
- visual difficulties- blurring/ moving/ inversed words and letters.
- magnocellular stream is atypical in dyslexia
what does a magnocellular deficit account for
behavioural results of impared visual motion and reduced contrast sensitivity at low spatial frequencies
How can the magnocellular deficit system be reduced?
- eye movements. letters appear to move (coverning one eye reduces errors)
- attention and peripheral vision (reducing field of view reduces errors)
what two explainations are there for dyslexia?
- Phonological processing deficit
- sesorimotor deficit
what is included within the sensorimotor deficit explaination of dyslexia?
temporal processing, magnocellular visual system, poss also cerebellum.
what did Ramus et al. find to be the only deficit found in every dyslexic patient?
phonological processing
what chromosomes are thought to have an influence on dyslexia?
15,6,1
what gives evidence for the heritability of dyslexia?
- family studies
- chromosomes
what is the direct biological evidence to the magnocellular theory? and when would these arise
Postmortem: magnocellular layers of the LGN were disordered, 30% smaller than average neurones (Galaburda and Livingstone, 1993). These differences arise during the 4th or 5th month of foetal development.
what is suggested that is needed for the magnocellular system to develop?
fish oils
what biological evidence suggests the phonological processing system may cause dyslexia?
Normal- asymmetry of L/R planum temporale (L is bigger)
Dyslexics- symmetrical or R is bigger
poss link between symmetry of L/R planum temporale and severity of phonological deficits
