Week 7 - Deep Dyslexia Flashcards
Dyslexia
• Dyslexia = reading disorder • Problem going from print to pronunciation of item • Acquired dyslexia • Developmental dyslexia
Deep Dyslexia
• First systematic study – Marshall & Newcombe
(1966)
• Typically an acquired reading impairment
• Cases of developmental Deep Dyslexia in the
literature
• Defining symptom semantic error in reading
aloud
• Symptoms of Deep Dyslexia
• Unvarying across cases of Deep Dyslexia
• Key symptom
• Semantic errors in reading single words out loud
eg. tandem > say “cycle” instead
cost > say “money”
• Visual errors
produce a word that looks similar to the presented word
eg. signal > single
• Visual-then-semantic errors
Visual error first than a semantic error on the replacement word:
eg. sympathy (symphony) > then say “orchestra”
favour (flavour) then say > “taste”
charter (chart) > map
What is the imagability effect?
• Better at reading concrete than abstract
words
eg − Better at saying butter and windmill than grief and
wish
Errors with abstract words are….
when trying to read abstract words will create visually related but highly imageable words, eg wish > wash
wash more concrete (highly imageable)
better at content than…
function words
Content words (nouns, verbs, adjectives)
Function words (was, quite, of)
• Function word errors
Different kind of function word
Was > with
If > yet
Quite > perhaps
(no access to semantic system) (can access the function word store but get it wrong)
• Morphological errors (derivational errors)
put letters in wrong place (listen to lecture)
eg. edition > editor
Courage > courageous
(derivational errors)
Very poor _____reading (____words)
nonword; nonsense
eg - brane, phocks
(GPC impaired)
Spelling and writing may be impossible
• If possible then symptoms are equivalent to
those listed above
• All patients with deep dyslexia show all of
these symptoms
Explanations for Deep Dyslexia
• Impairment(s) to the normal left hemisphere reading system through many different approaches OR • Reading occurs via a secondary right hemisphere reading system
Impairment to left hemisphere reading
system
• Deep Dyslexia patient reads via a multiply
damaged LH (Morton & Patterson, 1980)
• Nonword reading abolished – letter to sound rules abolished
• Direct connection between orthographic input lexicon and the phonological output lexicon
must be impaired as word reading is poor
• Function words – can do visual LDT and can
produce them as they typically make function
word substitution errors
• Problem must be one between word
recognition and word production
• Reading worse for abstract than concrete words, impairment semantic system that is
worse for abstract than concrete words
• Semantic system impaired semantic errors
e.g. canary parrot
• Damage to connection between semantic system and phonological output lexicon
• Deep dyslexic correctly understands a printed
word but makes a semantic error reading it
• Damage to component syntactic system processes prefixes and suffixes (morphological
errors in reading affixed words)
Right hemisphere hypothesis
• Both LH and RH approaches agree reading occurs
via orthography, phonology and semantics
(Coltheart, 2000).
• If LH cannot do one of these processes then RH
must take over
• Coltheart (1980) Deep Dyslexia loss access from
print to the LH orthographic lexicon
• Deep Dyslexia reads “word” via RH orthographic
lexicon semantic representation information
send to LH phonological lexicon to retrieve
phonology (“say word aloud”)
Right hemisphere reading
• Semantic errors – incorrect selection of target
from activated candidates LH
• Activation of nonword phonology in RH nonexistent
– cannot say nonwords
• Errors deep dyslexia due to use RH reading
system
Brain Damage
• Widespread damage to left hemisphere
• Developmental case – no damage cortex or
white matter
• Orthographic processing – left occipital and
occipitotemporal regions
• Semantic processing – border between superior
and middle temporal gyrus, areas BA21 and
BA22 (LH)
• Phonological output – LH frontal operculum
Diagnosis and rehabilitation of Deep
Dyslexia patient
Ska, Garneau-Beaumont, Chesneau &
Damien (2003)
Diagnosis and rehabilitation of DD patient
• Ska, Garneau-Beaumont, Chesneau & Damien
(2003)
• Assess reading of DD patient according to a
cognitive model of reading
• Assess a priming paradigm rehabilitation program
focus on the lexical route to reading aloud
• Patient JH 56 yrs old in 1997
• Suffered a left ischemic cereal vascular Sylvain
stroke following a triple aorta-coronary by-pass
operation
• Right hemianopsia, right brachio-facial
hemiparesis and receptive and expressive aphasia
symptoms
Diagnosis and rehabilitation of DD patient
• Appeared to have DD
• JH right handed physician, multi-lingual
• One year JH individually followed by speech
therapist 4 x week
• Two years in a rehabilitation program, 3
individual therapies a week, exercises to be
done at home and a weekly group therapy
session
• Dec 2000 JH began rehabilitation for his reading
problems
Assessment of JH’s Deep Dyslexia (DD)
Peripheral processes
Matching identical words Letter identification among visually similar letters Letter identification among auditorily similar letters Letter denomination Word and nonword repetition Unexpected delay repetition of words
Peripheral Processes
• Assess being able to process auditorily
presented words
• Repeat words & nonword aloud
• Match letters to spoken letters
• Also process individual letters that were
visually presented
Assessment of JH’s Deep Dyslexia (DD)
• Phonological route
Letter Reading (YES!) Phoneme Reading (No) Phoneme Identification (No)
Phonological route
Grapheme-phoneme route
- Letter reading
- Phoneme reading
- Phoneme identification
Assessment of JH’s Deep Dyslexia (DD)
• Lexical route
Reading words aloud - (No)
Reading non-words (no)
Assessment of JH’s Deep Dyslexia (DD)
• Assessing linguistic variables
- Word length effect
- Word frequency
- Orthographic complexity
- Concrete vs. abstract words
Assessment of JH’s Deep Dyslexia (DD)
• Error analysis
– semantic, phonological, visual,
morphological
Assessment of JH’s Deep Dyslexia (DD)
• Phonological lexicon
auditory lexical decision task (yes)
Assessment of JH’s Deep Dyslexia (DD)
• Orthographic lexicon
Failed - visual lexical decision
Passed - Irregular words letter switch task
Lexical Route (orthographic route)
•Reading words
•Reading non-words (type of errors relevant here)
•Visual lexical decision and letters switched within
a word
•Word length, frequency effects and orthographic
complexity
•Concrete vs. abstract (link with semantic system)
Assessment of JH’s Deep Dyslexia (DD)
• Semantic system
Passed all the following:
Odd item Odd item with subtle relations Written word-picture matching Semantic relation between picture and written word Picture-written word matching
Assessment of JH’s Deep Dyslexia (DD)
• Semantic system
failed all:
X Odd item
X Odd item with visually similar words
X Semantic matching
Semantic system
what, tests?
•Odd items
•Written word-picture matching
•Semantic relations between picture and word
•Picture-written word matching
•Matching and semantic relations task using only
verbal input
Assessment of JH’s Deep Dyslexia (DD)
• Phonological output lexicon
Passed:
Picture naming task
Semantic association task
Failed:
X Homophones
X Word designation
Phonological output lexicon
- Picture naming task
- Semantic association task
- Homophones
- Word designation
JH’s Deep Dyslexia (DD) summary
• Impaired phonological route to reading aloud
• Orthographic route to reading aloud impaired
even though he can read irregular words aloud
• Errors – semantic, morphological, phonological
for reading real words
• JH has deep dyslexia
Rehabilitation of JH’s Deep Dyslexia (DD)
• Aim to use matching pictures to their written
labels to build a new lexicon
• Tasks & Method: pre-test 140 concrete written
words (76 low freq, 64 high freq.)
• At pre-test 34 (24%) words read correctly
• No frequency effect
• 50 words that were badly read or not read were
selected for use in the training program
• Other 56 words not use in training
• Post-test: 140 words presented for reading aloud
• Post-test: run 1 week after rehab program, 8
month follow-up
Rehabilitation of JH’s Deep Dyslexia (DD)
• Training
• Weekly session with speech therapist.
• Words to be read aloud presented in blocks
• Each block practised once during a training
session
• Word written on one side of a card, picture and
word written on other side of card
• JH tried to read word alone, then look at picture
to identify word
• Word read by speech therapist
• JH invited to construct a mental association
between picture and written word
• Training (cont.)
• During the week JH read words twice a day
• Next session studied words assessed without
picture support and a new block of words
presented
• Final session were words presented that were
read incorrectly at the weekly meeting
• Total of five sessions
• Post-test and follow=up JH required to read all
140 words
Rehabilitation Results
• Post-test 84/140 (60%) word read correctly
– Trained words 90% correct
– Non-trained words 18% correct
– Original words correctly read 85% correct
• 8 month follow-up JH read 260 words (140 old
words)
– 55% correct original 140 words
– 84% correct on trained words
– 25% correct non-trained words
– 62% original words correctly read
Rehabilitation Implications
• After only 5 training sessions there was a
specific training effect
• No progress on control tasks
• Use of picture and auditory input assisted JH
• JH retained a high score on the trained words at
8 month follow-up despite no written contact
with these words during that time
• Training via the lexical route does not allow the
effects to generalise to learning new words
beyond those trained
• Training did increase JH’s motivation to continue
with reading
