Children at risk of dyslexia: How are they doing at 8 years

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Reading and language skills in children with Down
Syndrome results from a two year longitudinal
study
Kristina Goetz, Charles Hulme, Maggie Snowling,
Eleanor Barry and Sophie Brigstocke Centre for
Reading and Language Department of
Psychology University of York
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Down Syndrome (DS)

• Most common genetic cause of learning
  disabilities.
• Prevalence 1 in 800 live births (NICHD, 2005).
• Estimated that approx. 60,000 individuals with DS
  live in the UK (DS Association, 2005).
• 3 genetic variations
• Trisomy 21 accounts for 92 of cases
• Mosaic Trisomy 21 accounts for 3-4 of cases
• Translocation Trisomy 21 accounts for 3-4 of
  cases.

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Cognitive Profile in DS - Language

• DS has particularly severe effects on language
  development (Chapman, 1997 Fowler, 1990).
• Verbal IQ lower than performance on visual and
  spatial tasks (Chapman, 2003 Laws 2002).
• Weakness in auditory short-term memory relative
  to visual short-term memory (e.g. Laws, 2002
  Jarrold et al. 1997 2000).
• Mean length of utterances (MLU) are shorter
  (Rosin et al., 1988), and qualitatively different
  (Chapman, 1999 Chapman et al, 1998).
• Vocabulary is often at or above non-verbal mental
  age (e.g. Chapman et al., 1991).
• Divergence in receptive and expressive language
  that increases with age (Chapman, 1997).

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Cognitive Profile Phonological Awareness

• In groups of children with DS, phonological
  skills are often weak but nevertheless predict
  variations in childrens reading skills
  (Cardoso-Martins Frith, 2001 Snowling et al.,
  2002 Cupples Iacono, 2000).
• In these children, the development of
  phonological awareness follows a qualitatively
  different path to that of typically developing
  children (Snowling et al., 2002).
• - particular difficulties judging rime units
  (swing-ring) but in the presence of an ability
  to identify phonemes (cat-cow).

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Cognitive Profile in DS - Reading

• An area of relative strength! Great variability
  in level of achievements (Kay-Raining Bird et
  al., 2000 Laws and Gunn, 2002).
• Factors associated with reading
• cognitive ability (Sloper et al., 1990),
  language skills (Boudreau, 2002 Carr, 1995),
  phonological awareness (Kay-Raining Bird et al.,
  2000 Snowling et al., 2002).
• Evidence that children with DS are logographic
  readers (Buckley, 1985) and decoding skills do
  not develop in line with word recognition skills,
  possibly because of a lack of progress in
  phonological awareness (Kay-Raining Bird et al.,
  2000).

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Aims of current DS project

• To describe the cognitive profile and the
  literacy attainments of a group of children with
  DS who attend mainstream schools.
• To examine the relationship between language,
  reading and phonological skills in the DS group
  and in a group of typically developing (TD)
  controls.
• Longitudinal study including a short-term
  intervention.

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Participants at Time 1 (2003)

• TD Control Group
• (n 61)
• 604
• 409 906
• 30 male / 31 female
• All in Primary

• DS Group
• (n 49)
• Age 1005
• 506 1602
• Gender 22 male / 27 female
• School 36 Primary,
• 18 Secondary

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Participants Time 1 and Time 3

• DS Group
• (n 49)
• Age 1005
• 506 1602
• Time 3 (n45)
• 1208
• 710 1800
• Gender 22 male / 27 female
• Time 3 ? 18 male/27 female
• School 36 Primary / 18 Secondary.
• Time 3 20 P. / 22 Sec./ 3 Special

• TD Control Group
• (n 61)
• 604
• 409 906
• (n 57)
• 801
• 607 1010
• 30 male / 31 female
• ? 28 male / 29 female
• All in Primary
• All in Primary

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Vocabulary (Time 1 Time 3)Receptive
Vocabulary (BPVS) Naming Vocabulary (BAS II)
Test Battery
Non-verbal ability (Time 1) Pattern Construction
(BAS II)
Reading Letter-sound Knowledge Early Word
Recognition Word Reading (BAS II)
At Time 2 Time 3 Final Phoneme Matching
Phoneme Deletion Rhyme Production (PAT)
Phonological awareness Alliteration
Matching Rhyme Matching Phoneme Completion (PAT)
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Results

• 1) Evaluation of progress that the children made
• - Reading
• - Language
• (Vocabulary
• Phonology)

• 2) Relationships between language and reading in
  both groups

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Descriptives Time 1(Age-equivalents in years
months)
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Growth in Vocabulary Skills T1-T3
In DS group average increase of 6 months in
receptive and 8 months in expressive vocabulary
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Reading Skills across Time

• 4 children with DS have reading std scores gt 90
  These children have cracked the alphabetic code
  (near perfect LS knowledge, phoneme skills, good
  nonword reading).

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Phonological Tasks
DS
TD
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Percentage above chance on phoneme and rhyme
matching tasks
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Summary Progress

• Vocabulary Relatively slow growth in vocabulary
  in DS group, although some cases exceptional.
• Reading (More) progress in DS Group but not as
  much as in TD group.
• Phonology Weak phonological skills in DS group
  and many children are below chance on matching
  tasks. Progress in terms of awareness of initial
  and final phonemes but not rhyme skills (c.f.
  Snowling et al. 2002 Cardoso-Martins et al.
  2002, 2001).

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Simple Correlations, Reading and Phonology _at_T3DS
above diagonal TD below
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Partial Correlations, controlling for AgeDS
above diagonal TD below
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Concurrent Predictors of Reading _at_T3

• DS Group
• Step Variable Beta R² chge p
• Age .32 .10 .038
• 2 Vocabulary .72 .49 .000
• 3 Phonemes .07 .01 .540
• Phonemes .31 .09 .042
• 3 Vocabulary .70 .40 .000

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Concurrent Predictors of Reading _at_T3

• TD Group
• Step Variable Beta R² chge p
• Age .66 .44 .000
• 2 Vocabulary .14 .01 .361
• 3 Phonemes .58 .19 .000
• Phonemes .58 .20 .000
• 3 Vocabulary -.03 .00 .830

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Summary Predictors of Reading Time 1

• In DS Group Vocabulary is a unique predictor of
  reading skill but rhyme and phoneme skills are
  not.
• In TD Group Vocabulary does not predict variance
  in reading skill but phonological skills account
  for individual differences in reading ability.
• Note that at Time 3, regression analyses
  replicate those conducted at Time 1.

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Conclusion

• It is not safe to assume that reading development
  follows the same trajectory in atypical as
  typical development.
• Role of letter knowledge and phonological skills
• Rhyme deficit
• Importance of vocabulary.
• In the absence of good phonological skills,
  vocabulary may bootstrap reading in DS.
• Vocabulary may play at least 2 roles
• Providing a foundation for phonological skills
  (substantial correlations of about .7 between
  vocabulary and phoneme awareness in both DS and
  TD groups)
• Providing a semantic foundation for single word
  reading?

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Improving Reading Skills in DS

• 16 week intervention programme.
• Work on phonological awareness and
  letter-knowledge to boost reading.
• Small scale study involving 17 children with DS
  (emerging readers).
• Found significant increases in EWR,
  Letter-knowledge and improvement in BAS Reading
  and Alliteration.
• Needs replication with larger sample Vocabulary
  element in programme.

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Thanks to

• All participating children, their parents,
  teachers and support assistants
• Steve Grigg, Marion Weeks York LEA
• Louise Nasir, Aileen Gunn Speech Therapy
  Services
• Simon Gibbs, Kath Smith North Yorkshire LEA
• Susie MacKenzie Leeds Education Services
• Elaine Bull Calderdale LEA
• Sue Wong Down Syndrome Family Support Group
• Rachel Davis Down Syndrome Association
• Julia Carroll University of Warwick
• Pamela Baylis, Hannah Nash, Kim Manderson, Lisa
  Henderson University of York.

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Path ModelTypically Developing
ChildrenAge-Independent Variance
Vocabulary
.45
.35
.67
Phoneme
Reading
.37
R2 .33
Rhyme
c2 (3, N61) 5.75, ns, CFI 0.922, RMSEA
0.124 (CI.90 0.000 to 0.276)
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Path Model Down Syndrome ChildrenAge-Independent
Variance
Vocabulary
.80
.66
.35
.33
Phoneme
Reading
.43
R2 .67
Rhyme
c2 (2, N49) 2.38, ns, CFI 0.995, RMSEA
0.062 (CI.90 0.000 to 0.298)