Assessment and Treatment of Reading Disorders: A Cognitive Neuropsychological Perspective

Transcription

Assessment and Treatment of
Reading Disorders:
A Cognitive Neuropsychological
Perspective
DeCog Research Unit
(Developmental Cognitive Neuropsychology Research Unit)
MACCS, Macquarie University
Rehabilitation and Psychology Departments, The Children’s Hospital at Westmead
Brunsdon & Coltheart, 2005
Overview
!
!
!
Assessment of reading
Diagnosis of reading impairment
Treatment of reading difficulties
Print
Letter
Identification
L
E
X
I
C
A
L
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
Letter to Sound
Conversion
S
U
B
L
E
X
I
C
A
L
Dual Route Model
of Reading
!
Skilled readers use two main procedures for
reading aloud
• Lexical Reading Route
• relies on whole-word recognition and allows successful
and efficient processing of words that are familiar to the
reader
• Sublexical Reading Route
• involves rule-based letter to sound conversion and allows
the skilled reader to ‘sound-out’ unfamiliar words and
nonwords.
Developmental Dyslexia
Developmental Dyslexia
!
Developmental Dyslexia is heterogeneous
!
Main Subtypes
• Phonological
• Surface
• Mixed
Developmental
Dyslexia - Subtypes
!
Phonological Dyslexia
• children who have difficulty acquiring skills
for converting letters into sounds
!
• Difficulty with the Sublexical Reading Route
• the route that relies on letter to sound correspondences
to assemble a pronunciation.
• Over-reliance on the Lexical Reading Route
• the route that relies on whole word recognition
• where the reader gains access to an internal store of the
visual representations of familiar words
Print
Letter
Identification
L
E
X
I
C
A
L
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
Letter to Sound
Conversion
S
U
B
L
E
X
I
C
A
L
Phonological
Dyslexia
!
Phonological Dyslexia:
•
•
•
•
good reading of familiar words
Poor nonword reading
Difficulty reading unfamiliar word
Nonword reading errors
• visual similar real words
• eg. tapple → table
Developmental
Dyslexia - Subtypes
!
Surface Dyslexia
• children who have difficulty learning to
recognise words as whole units
Surface Dyslexia
!
Surface Dyslexia
• Difficulties with Lexical Reading Route
• the route that relies on whole word recognition
• Over-reliance on the Sublexical Reading
Route
• the route that relies on letter to sound
correspondences to assemble a pronunciation.
Print
Letter
Identification
L
E
X
I
C
A
L
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
Letter to Sound
Conversion
S
U
B
L
E
X
I
C
A
L
Surface Dyslexia
!
Surface Dyslexia:
•
•
•
•
good nonword reading
good reading of regular words (e.g., little)
poor reading of irregular words (eg. quay)
regularisation errors when reading
• eg. quay → “kway”
colonel → “kollonell”
Assessment
Assessment
!
Assessment of phonological, surface
and mixed dyslexia in children:
• Standardised word reading tasks
inadequate (eg. WRAT, WIAT)
• Only diagnose delay in general reading
development
• Do not detect specific types of dyslexia
Assessment
!
Cognitive Neuropsychological Assessment
• Structured according to existing models of
normal reading
• to determine which subprocesses are intact and which are not
Assessment
!
Core assessment Tools
• PALPA - Psycholinguistic assessment of
language processing in aphasia
Kay, Lesser & Coltheart (1992).
• Word/Nonword list
Coltheart & Leahy (1996)
• Graded Nonword Reading Test
Snowling, Stothard, & McLean (1996).
Print
Letter
Identification
L
E
X
I
C
A
L
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
Letter to Sound
Conversion
S
U
B
L
E
X
I
C
A
L
Assessment
• Sublexical Reading
• intact if nonword reading is age appropriate
• Word/Nonword list (Coltheart & Leahy, 1996)
• Graded Nonword Reading Test (Snowling, Stothard, & McLean, 1996)
Assessment
• Lexical Reading
• intact if irregular word reading is age appropriate
• Word/Nonword list (Coltheart & Leahy, 1996)
Assessment
• But, if impaired:
• why is the child having difficulties with the lexical
and/or sublexical processing routes?
• How do we treat the problem?
• Each process relies on the intact functioning of
a number of subprocesses each of which may
be dysfunctional
• We now need to assess each subcomponent of
Lexical and Sublexical Route
Print
Letter
Identification
L
E
X
I
C
A
L
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
Letter to Sound
Conversion
S
U
B
L
E
X
I
C
A
L
Assessment
Print
Abstract Letter
Identification
!
Intact if:
• child can complete a cross case
matching task normally (PALPA
Test 19 and 20)
a
A
e
Print
Letter
Identification
L
E
X
I
C
A
L
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
Letter to Sound
Conversion
S
U
B
L
E
X
I
C
A
L
Assessment
Print
Abstract Letter
Identification
Visual Word
Recognition
!
Intact if :
• irregular word reading
aloud is normal (Coltheart
and Leahy, 1996)
• child can complete a
lexical decision task
normally (PALPA Test 27)
Assessment
!
Lexical Decision: child must decide whether a
string of letters is a word
!
stimuli
•
•
•
•
regular words (like, fresh)
exception words (have, both)
pseudohomophones (brume, gane)
nonwords (mide, noast)
Assessment
!
child with a lexical deficit will rely on
phonological decoding (‘sounding-out’)
•
•
•
•
correctly accept regular words (e.g., like)
incorrectly reject exception words (e.g., both)
incorrectly accept pseudohomophones (e.g., brume)
correctly reject other nonwords (e.g., mide)
Print
Letter
Identification
L
E
X
I
C
A
L
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
Letter to Sound
Conversion
S
U
B
L
E
X
I
C
A
L
Assessment
Print
!
Abstract Letter
Identification
Orthographic
Input Lexicon
Semantic
System
Intact if:
• child demonstrates normal
knowledge of word meanings
through another modality
(other than reading)
• ie. child can name pictures
normally (PALPA Test 53)
• child can match spoken words
to pictures (spoken word picture matching,
PALPA Test 47)
Print
Letter
Identification
L
E
X
I
C
A
L
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
Letter to Sound
Conversion
S
U
B
L
E
X
I
C
A
L
Assessment
Print
Abstract Letter
Identification
!
Intact if:
• picture naming is normal
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
(PALPA Test 53)
• spontaneous speech is
normal
• child can provide a name
when given a spoken
definition
• e.g.. “What animal is large,
grey and has large floppy ears
and a long trunk?”
Print
Letter
Identification
L
E
X
I
C
A
L
Visual Word
Recognition
Semantics
Spoken Word
Production
Speech
Letter to Sound
Conversion
S
U
B
L
E
X
I
C
A
L
Print
Letter
Identification
Visual Word
Recognition
Semantics
Breaking the word
into ‘letter-chunks’
Letter-Sound
Associations
Sound
Blending
Spoken Word
Retrieval
Speech
Breaking the word
Letter(s)-Sound
Associations
Sound Blending
• Break up the word into
appropriate ‘chunks’
(eg. chooth or thick)
• Assign a sound to each ‘chunk’
- associate a letter/grapheme
with its corresponding sound
• Blend the sounds together convert a string of sounds into
a single unified spoken form
Assessment
Breaking the word
Letter(s)-Sound
Associations
Sound Blending
!
Intact if:
• Child can break down a
word into appropriate
chunks
• chick → ch i ck
Berndt & Mitchum (1994)
Brunsdon et al (2002)
Assessment
Breaking the word
Letter(s)-Sound
Associations
!
Intact if:
• Child has age
appropriate knowledge
of letter to sound rules
• Letter sounding and
spoken letter-written letter
matching (PALPA test 22)
Sound Blending
Assessment
Breaking word
Letter(s)-Sound
Associations
Sound Blending
!
Intact if:
• Blend sounds together to
make a single unified
pronunciation
• ie. if given the correct
phonemes (sounds) the child
can blend them together to
make the target word or
nonword
Treatment
Treatment
Cognitive Neuropsychological Rehabilitation
• Always follows a systematic and theoretically driven assessment
of the cognitive disorder
• Focus on direct remediation rather than compensatory strategies
• Conducted at an individual level
• Tailored to an individual’s specific pattern of impairment
• Carefully designed to evaluate treatment efficacy
Treatment
CASE STUDIES:
!
!
!
Sublexical Treatment
Lexical Treatment
Letter Processing Treatment
CASE DT
Brunsdon, R. K., Hannan T. J., Nickels, L., & Coltheart, M. (2002).
Successful treatment of sublexical reading deficits in a child with dyslexia
of the mixed type. Neuropsychological Rehabilitation, 12(3), 199-229
Case Description
!
DT
• 9 year old boy
• Year 5, mainstream primary school
Case Description
!
Neuropsychological Assessment Results
• Severe deficits in
•
•
•
•
•
Language processing
Verbal new learning and memory
Sustained and divided attention
Problem solving
Reading, spelling and numeracy
Treatment Study
• Pretreatment Assessment
•
•
•
•
lexical processing
sublexical processing
semantics
naming
Pre-treatment
Assessment
• General Reading
Word/Nonword Test
Irregular
Regular
Nonwords
10% (3/30) z <-2.41
17% (5/30) z <-2.41
3% (1/30) ) z <-2.27
Graded Nonword Reading Test
0%
Print
Letter
Identification
Visual Word
Recognition
Semantics
Breaking the word
Letter-Sound
Associations
Sound
Blending
Spoken Word
Retrieval
Speech
Sublexical Processing
Breaking words into chunks
30%
Letter(s)-Phoneme Knowledge
Letter Sounding
Grapheme sounding (e.g., ‘ch’)
56%
12%
Sound blending (aural)
20%
Print
Letter
Identification
Visual Word
Recognition
Semantics
Breaking the word
Letter-Sound
Associations
Sound
Blending
Spoken Word
Retrieval
Speech
Lexical Processing
Word/Nonword Test
Irregular
10% (3/30) z <-2.41
Print
Letter
Identification
Visual Word
Recognition
Semantics
Breaking word
Letter-Sound
Associations
Sound
Blending
Spoken Word
Retrieval
Speech
Lexical Processing
Visual Lexical decision
Regular words
Exception words
Pseudo homophones
poor
poor
many identified as words
Semantics and
Naming
Spoken word-picture matching
95%
Spoken picture naming
88%
Print
Letter
Identification
Visual Word
Recognition
Semantics
Breaking the word
Letter-Sound
Associations
Sound
Blending
Spoken Word
Retrieval
Speech
Pre-treatment
Assessment
!
Reading
• Mixed dyslexia
• Total inability to read non-words
• impairment in sub-lexical reading route
• Poor sight word vocabulary
• underdeveloped lexical reading route
• Comorbid cognitive difficulties
Treatment
!
Aims:
• To improve the operation of the
sublexical reading route
• To improve DT’s ability to ‘sound-out’ new
words.
Treatment Study
!
Aim
• To improve the functioning of all three
sub-components of the sublexical
reading route
Treatment Study
!
Two treatment phases (over 4 months)
1. Letter to sound associations
2. ‘Letter-chunking’ and sound blending
Treatment - Phase 1
1. Grapheme to phoneme associations
• Target stimuli
• 14 single letters
• 27 graphemes (e.g., ch, sh)
• Duration
• 8 weeks
Dd
Place this sheet in front of the child. Say “We are going to work on the sound ‘d’ (point to the D/d at
the top of the page). “Repeat after me” (sound ‘d’ 3 times allowing the child to repeat each time). Say
“Each of these words have the sound ‘d’ in them. Listen carefully and repeat after me”. (For each
line sound the letter “d” and then read the word - point to the letter ‘d’ and then the word as you read
them. Repeat each line 3 times).
d
d
d
d
d
d
d
d
d
d
dog
do
day
good
down
under
dad
dig
mad
and
Treatment - Phase 2
2. Letter chunking and sound blending
• Stimuli
• 2 nonword lists
• Duration
• 8 weeks
Treatment Study
2. ‘Letter-chunking’ and sound blending
• Method
•
DT was required to:
1. Circle each letter-group
2. Sound out each letter-group serially 3 times
3. Combine the sounds
Treatment Study
Did treatment work?
Two baseline assessments prior to
treatment:
•
•
•
Letter sounding
Grapheme sounding e.g., ‘ch’, ‘th’
Nonword Reading
Baselines
Base1ine 1
Baseline 2
Letter sounding
54%
58%
Grapheme – sounding
(e.g., ch oo th)
8%
17%
Nonword Reading
0%
3%
Results
Phase 1
Phase 2
B1
B2
54%
58%
92% *
92%
92%
Grapheme –
sounding (eg. ‘ch’)
8%
17%
88% *
92%
92%
Nonword Reading
0%
3%
18%
74% *
68%
Letter sounding
Midtreatment
Posttreatment
3 months posttreatment
Results
• Results
• Significant Improvement in:
• Sublexical reading skills (i.e., ‘sounding-out’
skills)
Results
• Generalisation to:
• word reading
• general phonology
• Treatment effects enduring
CASE TJ
Brunsdon, R. K., Hannan T. J., Coltheart, M. & Nickels, L (2002).
Treatment of Lexical Processing in Mixed Dyslexia: A Case Study.
Neuropsychological Rehabilitation, 12(5), 385-418
Case Description
!
TJ
•
•
•
•
10 year old boy
Year 5, mainstream primary school
Poor academic achievement
Delays in receptive and expressive language
development
Case Description
!
Neuropsychological Assessment
Results
• General cognition - low average range
• Poor problem solving
• Extremely limited reading and spelling
skills
Assessment
!
Assessment:
• Total inability to read non-words
• impairment of non-lexical reading route
• Extremely limited sight word vocabulary
• underdeveloped lexical reading route
Print
Letter
Identification
Visual Word
Recognition
Semantics
Breaking the word
Letter-Sound
Associations
Sound
Blending
Spoken Word
Retrieval
Speech
Treatment
!
Aims:
• To improve the operation of the visual word
recognition system
• To increase TJ’s sight word vocabulary
• 100 words targeted for treatment
• 14 or 15 words per week
Treatment
Study
• Treat list 1
• test lists 1, 2, 3, 4, 5, 6 etc
• Treat list 2
• retest lists 1-6 etc
• Treat list 3
• retest lists 1- 6 etc
• etc
Treatment
Study
• Stimuli
• Flash cards containing target words
• No picture cues
• Treatment
• Weekly training and testing sessions (≈30 minutes)
• daily home practice (≈5 mins)
Results
Weeks
po 7
st
1
po
st
2
6
5
4
3
2
1
B
2
100
90
80
70
60
50
40
30
20
10
0
B1
Correct
• Significant overall treatment effect
Results
% Correct
• Significant generalisation to untreated
words
30
25
20
15
10
5
0
1
2
3
4
Weeks
5
6
Results
• Significant improvement in spelling
80
70
60
50
% correct
40
30
20
10
0
pre
post 1 post 2
Results
• Results
•
•
•
•
Overall treatment efficacy
Generalisation of treatment effects to untreated words
Maintenance of treatment effects over time
Generalisation to spelling
• Cognitive neuropsychological theories and
rehabilitation methods can be useful for
children with severe mixed dyslexia.
• it is never to late to implement treatment even
in children with virtually no functional reading
skills
• Significant treatment gains despite severe
comorbid phonological, language and
cognitive impairment.
Discussion Point
• Traditionally used mnemonic cue may not
increase efficacy of training for all children
in early orthographic development
• ?May even be detrimental to efficient acquisition of
orthographic representations
Samuels, 1967
Stuart, Masterson & Dixon, 2000
CASE ET
Brunsdon, R. K., Coltheart, M. & Nickels, L (In press). Severe
Developmental Letter Processing Impairment: A Treatment Case
Study. Cognitive Neuropsychology
Case Description
!
ET
• 7 year old boy
• Year 2, mainstream primary school
Case
Description
!
Neuropsychological Assessment
Results
• Severe deficits in
•
•
•
•
IQ low average
History of language delay
Severe impairments in attention
Stimulant Medication since age 5
Case
Description
!
!
!
No reading or spelling abilities
Unable to name or sound letters
Very little improvement during Kindy
and Year 1
Assessment
!
Assessment:
• Letter Naming
• Letter Sounding
lower case
upper case
6/26
5/26
7/26
0/26
Assessment
!
Assessment revealed specific core deficits:
• Matching across case
• General letter knowledge
impossible
impoverished
Treatment
!
Aims:
• To improve ET’s ability to:
• Sound letters
Treatment
Focus on core impairments:
• Poor abstract letter
identification
• Training in
association of upper
and lower case with
a single sound
• Poor semantic
representation of letters
• Extensive semantic
elaboration
Treatment Study
• Treatment
• Daily training (≈15 minutes) at home by mother
• 26 letters
• 3 letters per week
Treatment
We used materials from Letterland (Manson & Wendon, 1997)
• Letterland flash cards
• Letterland ABC Book
• contains a short story about each character
• Letterland CD
• has a short song linking each letter character to
their sound, set to a common nursery rhyme tune
Treatment
!
Each day ET and his mother focussed on one letter
!
They
•
•
•
•
•
•
read the letter character story
looked at the lower case flash card and sounded the letter
sang the song
generated words beginning with the letter sound
looked at the upper case flash card and sounded the letter
Revision
Results
100
90
80
70
Abstract Letter
Identification
50
40
30
20
10
Follo
wup
Post
-trea
tmen
t
Base
line
2
0
Base
line
1
%Correct
60
2
1
Fol
low
up
Po
st-t
rea
tme
nt
Ba
sel
ine
Ba
sel
ine
%Correct
100
Results
90
80
70
Letter Sounding
60
50
40
30
20
10
0
Results
!
Also improvements in:
!
Reading words
Writing letters to dictation
!
What we have covered
!
Assessment of reading
• Identifying the underlying impairment
!
Treatment of Reading Disorders
• ‘Whole word’ processing
• ‘Sounding out’ skills
• Letter Processing
!
Monitoring Treatment Efficacy
References
Berndt, R., & Mitchum, C. (1994). Approaches to the rehabilitation of "phonological assembly": Elaborating the model of
nonlexical reading. In G.W. Humphreys & M.J. Riddoch, (Eds) Cognitive Neuropsychology and Cognitive Rehabilitation. London:
Lawrence Erlbaum.
Castles, A., & Coltheart, M. (1993). Varieties of developmental dyslexia. Cognition, 47, 149-180.
Castles, A., & Coltheart, M. (1996). Cognitive correlates of developmental surface dyslexia: A single case study. Cognitive
Neuropsychology, 13, 25-50.
*Coltheart, M., & Leahy, J.(1996).Assessment of lexical and nonlexical reading abilities in children: Some normative
data. Australian Journal of Psychology, 48, 136-140.
*Edwards, V., & Hogben, J. (1999). New norms for comparing children's lexical and nonlexical reading: A further look at
subtyping dyslexia. Australian Journal of Psychology, 5, 37-49.
Gathercole, S., & Baddeley, A.(1996). The Children's Test of Nonword Repetition. London: The Psychological Corporation Ltd.
Kay, J., Lesser, R., & Coltheart, M. (1992). Psycholinguistic assessments of language processing in aphasia (PALPA). Sussex,
UK: Lawrence Erlbaum Ltd.
Manson, J., & Wendon, L. (1997). Letterland Early Years Handbook. Letter Land International: Cambridge.
(http://www.letterland.com)
Samuels, S.J. (1967). Attentional processes in reading: The effect of pictures on the acquisition of reading responses. Journal of
Educational Psychology, 57, 337-40
Snowling, M., Stothard, S., & McLean, J. (1996). Graded Nonword Reading Test. Suffolk, England: Thames Valley
Test Company
Stuart, M., Masterson, J., & Dixon, M (2000). Spongelike acquisition of sight vocabulary in beginning readers? Journal of
Research in Reading, 23, 12-27.
*Norms for Word/Nonword Test

Assessment and Treatment of Reading Disorders: A Cognitive Neuropsychological Perspective

Transcription

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