The mysterious fourth quadrant: Children who read accurately despite language impairment

1
The mysterious fourth quadrant Children who
read accurately despite language impairment

• Dorothy Bishop
• University of Oxford

http//www.psy.ox.ac.uk/oscci/
2
Note from the author

• The data reported in this presentation are part
  of work in progress. Please do not cite. A paper
  on this study is in preparation, and will be made
  available in due course.
• 26th April 2007

3
The traditional view separate disorders
dyslexia
studied by speech and language therapists
studied by educators/ psychologists
4
Oral language deficits in dyslexics 1. language
delay

• Retrospective report of language delay more
  frequent in dyslexic than controls
• e.g. Naidoo, 1972 Rutter Yule, 1970
• Prospective studies higher rates of language
  delay in children of dyslexic parents
• e.g. Gallagher et al, 2000 Lyytinnen et al, 2001

5
Oral language deficits in dyslexics 2. poor
phonological processing

• Phonological awareness deficits
• Poor at nonword repetition
• Slow at naming familiar items

6
Literacy problems in children with SLI

• Bishop Adams, 1990
• Snowling et al, 2000
• Conti-Ramsden Durkin, 2007
• High rates of reading disability in children with
  SLI

7
Continuum viewcommon core phonological deficit
in SLI/dyslexia, varies in severity
Predicts that children with SLI will have the
same problems as dyslexics, but with additional
difficulties
SLI
dyslexia

8
What about poor comprehenders?

• Children selected for mismatch between good
  decoding and poor reading comprehension
• Have good phonological skills
• Weak semantic skills
• Poor with exception words/low frequency word, but
  good with nonwords
• Many meet criteria for SLI on test
• see Nation (2005) for review

9
Bishop Snowling, 2004
typical development
classic dyslexia
poor ----- oral language ----good
poor comprehenders ?
classic SLI (poor reading)
poor ----- phonological processing ----good
10
Catts et al, 2005Kelso et al, 2007

• Although SLI and dyslexia often co-occur, they
  can be dissociated
• Some children with SLI can read words accurately
  and dont have phonological impairments

11
Specific question

• What distinguishes language-impaired with good
  decoding from other groups?
• Can this provide insights to help us teach
  literacy to other children with language
  impairments?

12
SLI who can read accuratelyare they like poor
comprehenders?
typical development
classic dyslexia
poor ----- oral language ----good
SLI without reading problems
classic SLI (poor reading)
poor ----- phonological processing ----good
13

• If so, they should
• Be poor at reading comprehension
• Be poor at processing irregular words
• Have adequate phonological skills
• Be less likely to be identified as having
  problems than typical dyslexic/SLI

14
Subsidiary questionWhere does rapid naming fit
in?

• Rapid naming and phonological awareness can be
  dissociated
• Severe dyslexics typically poor at both
• Rapid naming traditionally seen as a phonological
  measure
• But would it be more accurately viewed as a proxy
  measure for more general language impairment?

15
Bishop Snowling model
typical development
classic dyslexia
poor ----- oral language ----good
X
SLI without reading problems
classic SLI (poor reading)
poor ----- phonological processing ----good
16
Study of 9-year-olds from Twins Early
Development Study
17
Numbers of twin pairs (same-sex) recruited to
study
18
Current study

• Sample of 9-yr-olds subdivided according to
  reading (single word) and language status
• Reading (accuracy) disability only (RD)
• Language impairment only (LI)
• RD LI
• No impairment

19
Test battery at 9 years

• Wechsler Abbreviated Scale of Intelligence
• Block Design
• Vocabulary
• (Matrices)
• (Similarities)

• TOWRE
• single word
• phonemic decoding
• NARA
• accuracy
• comprehension
• rate
• Spelling
• speeded, in house test

20
Sample items from spelling test

• Regular
• three
• chest
• house
• first
• strain

• Irregular
• knock
• guide
• yacht
• rhyme
• chemist

21
Test battery at 9 years (ctd)

• Woodcock-Johnson
• Understanding Directions
• ERRNI
• Story telling
• Story recall
• Comprehension
• MLU

• NEPSY
• Sentence repetition
• Nonword repetition
• Oromotor sequences
• Memory for names
• PHAB
• Rapid digit naming
• Rapid picture naming

22
All tests restandardized relative to
representative subset of sample
23
Why no phonological awareness measure?

• Good evidence that PA is as much as consequence
  as cause of poor literacy
• Poor PA in illiterate cultures
• Influence of orthography on PA tasks, even if no
  written language, e.g. swan-man
• Simple PA has ceiling effects by 5 yr
• To be sensitive at older ages, PA tasks must
  include executive/memory components, e.g.
  Spoonerisms

24
Number of children with single or double deficit
N.B. much higher association between RD and LI
than Catts et al (2005)
25
NB. No differences between LI vs RDLI equally
severe language impairments
26
Literacy measures

• Prediction 1
• LI-only group will be poor at reading
  comprehension, despite adequate reading accuracy
  for single words

27
(No Transcript)
28
Literacy measures

• Prediction 1
• LI-only group will be poor at reading
  comprehension, despite adequate reading accuracy

• NARA comprehension significantly worse than TD
  group
• NARA accuracy also impaired
• However, relatively mild deficits
• Accuracy-comprehension mismatch less than in
  poor
• comprehenders from other studies

29
Literacy measures

• Prediction 2
• LI-only group will be poor at processing
  irregular words

30
Spelling errors
31
Literacy measures

• Prediction 2
• LI-only group will be poor at processing
  irregular words

32
Phonological measures

• Prediction 3
• Phonological processing will be relatively spared
  in LI-only group

33
(No Transcript)
34
Phonological measures

• Prediction 3
• Phonological processing will be relatively spared
  in LI-only group

• LI-only as poor as RD-only on nonword repetition
  
• memory for names and oromotor skills
• Though lowest scores in RDLI group
• NB less deficit in RD-only than in other
  studies
• - could be because those with comorbid LI
  excluded

35
Clinical concerns

• Prediction 4
• LI-only group will be children who are not
  identified clinically

36
Experience of speech-language therapy

• LI do not differ from RDLI
• Higher rates of SALT in LI than in TD

37
Clinical concerns

• Prediction 4
• LI-only group will be children who are not
  identified clinically

• True for some, but around half had
  speech-language
• therapy contact

38
Rapid naming

• Prediction 5
• Rapid naming will be a correlate of LI status
  rather than RD status, and so will be OK in
  RD-only and poor in LI-only and LIRD

39
(No Transcript)
40
Rapid naming

• Prediction 5
• Rapid naming will be a correlate of LI status
  rather than RD status, and so will be OK in
  RD-only and poor in LI-only and LIRD

• LI-only group are normal on rapid naming task
• RD-only group are impaired (mildly)

41
Summary What do LI have in common with
typically-developing?
42
Comparison of LI-only with typically developing
43
SummaryWhat distinguishes LI from LIRD?
44
Comparison of LI-only with LIRD 9 yr data
45
Poor phonology/processing and reading impairment
cause or consequence?
46
Were LI different from others at 4 or 6 years of
age?
47
LI only group reading at average level at 6 years
48
Were LI different from others at 4 or 6 years of
age?

• Data from earlier time points available for
• 84 typical developing
• 9 RD (atypical subset
• excluded here from analysis)
• 17 LI
• 21 RDLI
• Time 1 4 years Time 2 6 years
• Time 3 9 years

49
LI and LIRD indistinguishable at 4 years
50
4 yr McCarthy Perceptual 6 yr WASI PIQ 9 yr
WASI Block design
LI do not differ from LIRD at any time
51
4 yr McCarthy word knowledge 6 yr WASI
Vocabulary 9 yr WASI Vocabulary
Significant interaction time x group LI do not
differ from LIRD at time 1 or 3, but do differ
at time 2
52
4 yr BAS Comprehension 6 yr CELF Sent.
Structure 9 yr WJ Understanding
No interaction time x group LI do not differ
from LIRD at any time
53
Sentence repetition
4 yr McCarthy l 6 yr CELF-R 9 yr NEPSY
LI do not differ from LIRD at any time
54
LI do not differ from LIRD at any time
55
Differences in phonological processing emerge
over time

• Nonword repetition and oromotor (articulation)
  groups diverge with age

56
4 yr CNRep 20 items 6 yr CNRep 40 items 9 yr
NEPSY
Significant interaction time x group LI do not
differ from LIRD at time 1, but do differ at
times 2 and 3
57
4 yr Goldman Fristoe articulation 9 yr NEPSY
oromotor
LI do not differ from LIRD at time 1, but do at
time 3
58
Poor phonology/processing and reading impairment
cause or consequence?
59
SummaryLanguage-impaired children who are good
decoders

• Reading comprehension mild deficit
• Better at reading/spelling single words than
  connected text
• Less impaired than other LI on phonological tasks
• NO IMPAIRMENT in rapid naming
• Fit quadrant model if rapid naming part of
  phonological dimension

60
Implications for intervention?

• Good news even quite marked semantic impairments
  need not preclude development of decoding
• see also studies of Down syndrome, autism

61
Implications for intervention?

• Bad news? little difference between LI and LIRD,
  except rapid naming
• Few clues as to what to train
• Also, rapid naming hard to train De Jong et al
• Or is it good news? Does this mean the
  difference between LI and LIRD is purely related
  to education?
• Phonological task differences are plausibly
  consequence of learning to read
• Might this also be the case for rapid naming?

62
Acknowledgements
6-yr-old twin testers
9-yr-old twin testers
Caroline Adams Courtenay Norbury
David McDonald Sarah Bird

• Robert Plomin and staff at the Twins Early
  Development Study

63
Dorothy Bishop Oxford Study of Childrens
Communication Impairments, Department of
Experimental Psychology, South Parks
Road, Oxford, OX1 3UD, England. http//psyweb.ps
y.ox.ac.uk/oscci/