When does phonological impairment cause literacy problems

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When does phonological impairment cause literacy
problems?

• Dorothy Bishop
• Experimental Psychology
• University of Oxford

Powerpoint and references will be on my website
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What we have learned today

• Phonology is not a single skill
• Segmental vs. higher-level structure
• Input vs. output
• Perception vs. memory
• Hard to disentangle, but people are devising
  wonderfully ingenious tasks

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Why is phonology important in reading?

• Two ways to learn to read a word
• If word is totally unfamiliar decode letters
  into sounds to achieve pronunciation

CAMEL
/k//a//m//e//l/
/'kaml/
/kamel/
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Phonological skills involved in decoding

• Knowledge of mappings from letters to sounds
• Distinct representations of phonemes
• Ability to segment syllables into phonemes
• Combine sequence of sounds into syllables
• Match assembled string to a similar lexical entry

• Learn to do this rapidly with larger orthographic
  units

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Why is phonology important in reading?

• Another way to learn to read a word
• Incorporate orthographic information in lexical
  representation of a known word

/kaml/
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Why is phonology important in reading?

• Another way to learn to read a word
• Incorporate orthographic information in lexical
  representation of a known word

Does not require phonological analysis
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Reading without decoding

• Patient PS, L hem. infarct aged late 40s
• Phonemic errors on reading aloud and spontaneous
  speech
• Excellent comprehension of written words can
  judge synonyms, define words, match to pictures
• Homophones can only relate to correct meaning,
  i.e. cannot respond inherits to word air
• Nonwords very poor at reading

Hanley, J. R., Mcdonnell, V. (1997). Are
reading and spelling phonologically mediated?
Evidence from a patient with a speech production
impairment. Cognitive Neuropsychology, 14, 3-33.
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Todays talk raise questions about causation
Phonological skill
Literacy
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What has not been discussed
Phonological skill
Literacy
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Phonological deficits in dyslexia a symptom
rather than a cause?

• Evidence from
• Orthographic influences on phonological tasks
• Phonological processing in non-literate people
• Phonological skills as predictors of literacy
• Literacy in children with sensory or motor
  conditions affecting phonology

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1. Orthographic influences on phonological tasks
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Orthographic influences on phonological judgement
Judging whether pictures have rhyming
names Children more accurate if can use
orthography Bishop et al, 1989
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Orthographic influences on phonological judgement
Phoneme awareness task performance affected by
orthography
Castles et al, 2003

• Tasks where orthography no help (or may hinder)
• e.g., take the 'w' from squabble
• cf. transparent condition
• e.g., take the 'r' from struggle
• Also phoneme reversal gnat vs mood.

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2. Phonological processing in non-literate people
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Phonological processing in non-literate people

• Illiterates, who lack the linguistic construct
  phoneme, cannot perform oral tasks that require
  the awareness of that construct
• Tarone Bigelow, 2005, p 82
• Seminal study by Morais et al (1979)
  Non-literate Portuguese worse than Belgian
  first-graders at tasks of phoneme
  deletion/addition those with some literacy
  attainments did better

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Comparison of literate vs. nonliterate adults
summary

• Do not differ on
• Rhyme judgement
• Phoneme discrimination
• Word repetition
• Nonword repetition (short)
• Categorical perception

• Do differ on
• Phoneme deletion
• Phonological fluency
• Nonword repetition (long)

but less precise categorical boundary
Serniclaes et al, 2005 See also Kosmidis et al,
2004 Castro-Caldas et al, 1998 de Santos
Loureiro et al, 2004
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3. Early phonology measures as predictors of
later reading
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Early phonology measures as predictors of later
reading

• Bradley and Bryant (1985) famous demonstration
  that preschool phonological awareness accounted
  for significant variation in reading outcome
  after allowing for IQ, vocabulary.
• BUT!
• ...the sound categorization tests that we gave
  to the 4-year-old children were really rather
  good at picking up those children who would
  eventually become good readers. The percentage
  success .. ranged from 40 to 53. On the other
  hand, these same tests were very weak indeed at
  predicting reading failure. The successful rate
  of prediction of poor readers ranged from as low
  as 14 to 28.
• Bradley Bryant, p. 105

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Wimmer et al, 1991

• At start of grade 1 (children non-readers), good
  PA predicted good reading 7 mo later, but many
  with poor PA also did well. Children differ in
  the ease with which they pick up PA when
  introduced to literacy.
• Positive correlation between preschool phonology
  and later reading could be consequence of some
  preschoolers reading (see also Castles and
  Coltheart, 2004)

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• Bishop et al (in press) comparison of pure LI and
  LI reading disability (RD)
• Retrospective analysis of measures taken at 4
  years. Did not differ on
• Nonverbal ability
• Vocabulary
• Oral comprehension
• Sentence memory
• Phonological awareness
• Nonword repetition

NB significantly impaired at 4 yr on all these
when compared to control group
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time 1 4 yr time 2 6 yr
LI do not differ from LIRD at any time
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4 yr CNRep 20 items 6 yr CNRep 40 items 9 yr
NEPSY
time 1 4 yr time 2 6 yr time 3 9 yr
Significant interaction time x group LI do not
differ from LIRD at time 1, but do differ at
times 2 and 3
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4 yr Goldman Fristoe articulation 9 yr NEPSY
oromotor
time 1 4 yr time 3 9 yr
LI worse than LIRD at time 1, but do worse still
at time 3
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Differences in phonological processing emerge
over time

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

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4. Children with sensory or motor problems
affecting phonology
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Children with impaired speech production

• In general, these do not seem to impair decoding
  unless accompanied by broader language
  difficulties
• Structural problems e.g., cleft palate
  (Stackhouse, 1982)
• Neurological problems, e.g. cerebral palsy
  (Bishop Robson, 1989)
• Problems of unknown (?genetic) origin, - speech
  sound disorder (see review by Pennington
  Bishop, in press)

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Children with impaired phoneme discrimination

• Study comparing children with mild-moderate
  hearing loss and those with SLI
• Briscoe et al, 2001
• Hearing impaired had sensorineural hearing loss
  from 25 to 65 dB across speech frequencies

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Phonological discrimination

• Bridgeman Snowling test
• Same/Different judgements re real and nonwords
  with final s, t, st, or ts
• Different differ either in single segment (e.g.
  tot vs. toss) or in sequence (e.g. gets vs.
  guest)

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Phonological discrimination

significant difference from group CA
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Phonological awareness task
(Introducing monster) This is Wug. He likes
things that sound like his name. Which do you
think he will choose? The cake, the jug, the leaf
or the boat?
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Phonological awareness

significant difference from group CA
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WORD single word reading
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Nonword reading
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Conclusion re hearing loss

• Mild-moderate hearing loss affects phonological
  discrimination and awareness, and nonword
  repetition (Briscoe et al)
• Yet children with mild-moderate hearing loss do
  much better than those with SLI on literacy
• see also Halliday Bishop, 2005
• Wake et al., 2006

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Questions for discussion

• Is phonological deficit a causal deficit in SLI
  or dyslexia?
• Is profile of phonological deficits in
  SLI/dyslexia the same as that in illiterates?
• What are implications for intervention?
• Do we really understand how a phonological
  deficit could cause literacy problems?
• How important is nonsegmental level for
  understanding SLI?
• Why so little funding for research on these
  disorders compared with autism?