1 Specific Language Impairment and Dyslexia Chloë Marshall Department of Language and Communication Science, City University London Keynote talk at the Dyslexia Action Summer Conference, 30 th June 2011
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Specific Language Impairment and Dyslexia
Chloë Marshall
Department of Language and Communication Science, City University London
Keynote talk at the Dyslexia Action Summer Conference, 30th June 2011
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Significant difficulties in learning to read and spell, despite:
Significant difficulties in acquiring expressive language and language comprehension, despite:
Adequate exposure to literacy Adequate exposure to language
Normal sensory abilities Normal sensory abilities
Average or above average non-verbal IQ
Average or above average non-verbal IQ
No additional developmental disorder that could explain literacy difficulties
No additional developmental disorder that could explain language difficulties
DyslexiaSpecific Language Impairment (SLI)
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Characteristics of SLI(example from boy aged 8)
SLT: What does your brother Ryan like to eat?CHILD: Pot noodle and chips SLT: And what about you? CHILD: And he’s like crispsSLT: He likes crisps, what about you? CHILD: I just like icecream, not pot noodle. SLT: You don’t like pot noodle? CHILD: I think it’s disgusting. SLT: I agree with you! CHILD: Make me sick. Started to hurting.
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Characteristics of SLI(same child as before)
CHILD: And the girl was thinking to eat the chocolate,making a mess. Suddenly the girl was filled with a mess! And the lady was bit surprise!
SLT: And who is that lady? CHILD: The mum! The lady clean him on his face. SLT: On her face. It’s a girl, isn’t it? CHILD: The girl. SLT: So she cleaned her on her face, that’s
right. What will she do with the clothes? CHILD: Make him dirty. SLT: Well, the girl’s made them dirty so what will
mummy do with the clothes? CHILD: Take them to the wash!
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Some characteristics of SLI
• Errors in:– Syntax– Morphology– Vocabulary– Phonology
• Also found in signed languages
• Affects around 7% of preschool children
• Can persist into adolescence/ adulthood
• Has a genetic component
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Overlap between dyslexia and SLI
McArthur et al (2000): 102 children: SLI (aged 6-9) 110 children: dyslexia (aged 7-14)
50 113 49SLI Dyslexia
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Understanding the overlap
• Challenges:– identified at different ages, by different professionals
• Perhaps SLI turns into dyslexia?
• Many preschool children diagnosed with SLI go on to have dyslexia.
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Bishop and Snowling’s additional deficit model (2004)
dyslexia normal
SLIpoor
comprehenders
phonology-
-
language
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Bishop & Snowling’s model in a different format
Phon. processing deficit Dyslexia Word reading problems
Oral language difficultiesLanguage deficits SLI
Problems: • Not all children with SLI have dyslexia.• Not all children with SLI have phonological deficits
of the type found in dyslexia
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Profile of a child with SLI, but not dyslexia
Boy, aged 12;11 Standard score
Literacy: WORD
single word reading 103
spelling 100
comprehension 72 (-1.87)
Phonology:
PhAB
rhyme 95
spoonerisms 98
rapid naming - digits 94
non-word reading 100
Language
sentence comprehension 88
word comprehension 75 (-1.67)
sentence repetition 65 (-2.33)
test of word-finding 83 (-1.15)
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Additional difficulties:Passive sentences
The man is eaten by the fish
(scored 7/12; actives, 12/12)
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Additional difficulties:Verb inflection
Buzz is stirring his tea. Everyday Buzz stirs his tea. Yesterday Buzz stirred his tea.
Agreement: 16/20Past tense: 12/20
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Study to investigate language, literacy and phonology in SLI and dyslexia
• Funded by ESRC, 2004-2008, at UCL.• Groups of children 8-12 years-old:
– SLI+dyslexia– SLI-only– Dyslexia-only
• Investigating phonological deficits and links to language deficits.
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Comparing children with SLI+dyslexia, SLI-only and dyslexia-only
-2.5
-2
-1.5
-1
-0.5
0
0.5
z-sc
ore SLI + dyslexia
SLI only
Dyslexia only
TROG BPVS CELF-rs TWF
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Comparing children with SLI+dyslexia, SLI-only and dyslexia-only
-3
-2.5
-2
-1.5
-1
-0.5
0
z-sc
ore SLI + dyslexia
SLI only
Dyslexia only
WORDread
WORDspell
WORDcomprehension
PhABnw read
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Phonological impairments in SLI and dyslexia
SLI+Dyslexia SLI-only Dyslexia-only
Age-matched controls
Speech perception
(log)
0.17 0.20 0.30 0.57
Non-worddiscrimination
(%)
73 80 78 90
Non-wordrepetition
(%)
51 68 78 96
Digit span(raw)
9 10 11 16
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How do phonological impairments contribute to language impairments?
Verb morphology: phonological variables account for:
49.7% variance, highly significant
Passive sentence comprehension: phonological variables account for:
11.3%, significantly less than for verb morphology
Contribution of phonology depends on particular grammatical construction. Not all phonology!
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Summary
• Many children with dyslexia have SLI, but not all.
• Many preschool children diagnosed with SLI go on to have dyslexia.
• Children with SLI may, however, have adequate single word reading skills, BUT have difficulties with reading comprehension.
• Children with both SLI+dyslexia often score particularly poorly on language and literacy assessments.
• Poor phonology underlies some of the language impairment in SLI, but is not the whole story.
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Find out more about SLI (SLCN)
• I CAN:
http://www.ican.org.uk/
• Afasic:
http://www.afasicengland.org.uk/
• National year of communication –
Hello campaignhttp://www.thecommunicationtrust.org.uk/hello.aspx