reading 2 - dyslexia Flashcards
dyslexia DSM-V definition
Difficulties in accuracy or fluency of reading that are not consistent with the person’s chronological age, educational opportunities or intellectual abilities
dyslexia British Dyslexia Association definition
Dyslexia is a specific learning difficulty that mainly affects the development of literacy and language related skills. It is characterised by difficulties that may not match up to an individual’s other cognitive abilities
NHS - dyslexia prevelence in UK
up to 1 in 10 people in the UK have a certain degree of dyslexia
what is dyslexia
many definitions mention decoding of written words - importance of fast and efficient decoding and word recognition
issue with phonological processing and how speech sounds correspond to letters - leads to fluency issues
not a visual problem - demonstrated by difficulty identifying phonemes (kids with dyslexia find it hard to say “skip” without the ‘p’)
caused by interaction of gene and environment - puts some more at risk than others
identifying dyslexia - tasks to assess skills (3)
decoding skills –> converting graphemes into phonemes –> task = phoneme deletion/substitution (e.g. say speech without the ‘s’) ; decoding pseudowords (e.g. say ‘veep’ - nonword)
lexical retrieval skills –> recognise whole words e.g. activate representations in an orthographic lexicon –> task = rapid automatic naming (RAN) tasks ; word identification of regular and irregular words
verbal short-term memory skills –> retain information in STM –> task = word span ; digit span
longitudinal study of phonological awareness - through primary school
De Jong and van der Leij (2003)
phoneme identification:
- say “speech” without the ‘s’
- say the first sound in the word “train”
group into: dyslexic, weak readers, and normal
found no deficit in kindergarten
problem appeared in the first year of learning to read
problem disappears by end of primary school (6th year)
reading impairment profiles in dyslexia - longitudinal study from age 5-7
Nation (2019)
dyslexic participants only
worse performance on measures of phonological awareness at age 7 compared to age 5
study of automatic word processing in dyslexia
De Jong and van der Leij (2003)
2 measures:
RAN task - name images, letters, digits as quickly as possible
- dyslexic and weak readers are slower to name objects than control
identification of words and non-words
- dyslexic readers name fewer objects and fewer correct words than control group
- doesn’t mean they can’t do it, but do it with less fluency or speed
dyslexic profile (2 components)
poor phonological awareness
- problems identifying phonemes
- problems reading non-words
slow lexical retrieval
- slow retrieval of letters - in RAN task
- slower word reading for dyslexic group compared to weak + normally developing readers
which route of DRC is there a deficit in dyslexia
could be lexical or non-lexical
deficits in non-lexical could lead to problems in lexical –> issues reading non-words
phonological deficit in dyslexia - issues this causes later in life
Initial problems linking phonemes and graphemes results in problems with word reading later in development
Difficulties in reading later in life may be due to phonological deficit when learning to read – less robust orthographic lexicon – less fluidity in reading
difficulty de-coding words:
- Unlikely to be motivated to read
- Reading (exposure to print) facilitates the development of an orthographic lexicon
- Development of an orthographic lexicon facilitates ‘skilled’ reading
reflected in slower identification and reading of correct words in later stage of development
key time for learning to read
end of first year of school - based on phonological processing
difference in ability - phonological awareness - is most pronounced here
orthographic learning and self-teaching
decoding skill creates opportunities for self-teaching but does not guarantee that orthographic learning will take place (Share, 2011)
orthographic learning and dyslexia
weak phonological processes affect the formation of orthographic representations
BUT Orthographic learning may be affected independently of phonological processes
the result could be an ‘Unexpectedly poor speller’ or a subtype of dyslexia called ‘Surface’ Dyslexia
surface dyslexia
typical decoding, reading speed but difficulty in spelling
reading is preserved by orthographic issues are present (cannot spell)
phonological awareness appears unimpaired
non-word reading is within a ‘normal’ range
irregular word reading is impaired – break is read as ‘breek’
unable to distinguish between homophones – difficulty telling which of the following is a vegetable been or bean
surface vs phonological dyslexia - irregular word study
Wybrow et al. (2015)
tests of irregular compared to regular word reading have highlighted differences in dyslexic profiles
Results for reading a list of irregular words - demonstrates evidence of a deficit in the lexical route
surface dyslexic = more regularisation errors for irregular words than control
phonological dyslexic = less regularisation errors for irregular words than control
testing reading impairment profiles (surface and phonological dyslexic) - study
Peterson et al., (2013) study 1
Large samples of dyslexic populations allow for tests of different profiles to be conducted
3 tests:
- phonological awareness -> phoneme deletion
- Rapid Automatic Naming -> images & colours
- orthographic coding -> which of the following is a flower? Rose vs Rows
results:
phonological awareness = phonological are worse
rapid naming = surface are worse (closer)
orthographic coding = surface are worse
LOOK AT DIAGRAM
evidence of surface dyslexia as a subtype (3)
Bailey et al (2004) Surface dyslexics had difficulty learning a set of irregular words such that they could recognise them and read them out loud
Ziegler et al. (2008) found evidence of a surface dyslexic subtype in children diagnosed with developmental dyslexia compared to a chronological age control group
Naama Friedmann and Max Coltheart (2016) describe a variety of types of developmental dyslexia
2 routes of DRC for dyslexic subtypes
Ziegler et al (2008)
Surface dyslexia:
Deficits to the lexical Route
No problems reading regular non-words
Problems reading irregular words
Phonological dyslexia:
Deficits to the non=lexical route
Problems reading non-words
Impairment of non-lexical (GPC) route
debate over existence of subtypes of dyslexia
review of 5 studies Sprenger-Charolles & Serniclaes (2003)
concluded that -
“These results are more in line with the hypothesis that a phonological deficit is at the core of developmental dyslexia, than with the idea that a clear dissociation exists between surface and phonological profiles”
semantic processing in individuals with dyslexia
“Children with dyslexia have serious difficulties with forming detailed orthographic representations necessary for fluent reading. As a compensatory mechanism, they tend to rely more on semantic processing for reading than their typically reading peers. That is, stronger influences of semantics on word reading can be expected in this group compared with typical readers”
processing words using partial de-coding
using context to work out what the word is
e.g. read “pint” - irregular word
activates potential words e.g. paint, pit, pot, plot, post
then use context e.g. “ lets go for a pint” to figure out which word is correct
lexical access - context
Participants started to repeat specific words from recorded sentences 200ms after word onset,
But only if the sentences made sense
“ the car travelled down the motorway”
“ the aeroplane travelled down the motorway”
language system predicts which words might come up next and activate them
semantic processing with dyslexia
predicting next item - use of context
then build up the word from sounds you can understand
semantic processing with dyslexia - study with homographs
Frith & Snowling 1983
- tested children’s ability to correctly read out loud sentences that ended with a homograph (spelled the same – pronounced differently)
- “before he made his speech he gave a bow”
- dyslexic children were more likely to correctly pronounce ‘bow’ than controls
semantic processing with dyslexia - study with reading words in isolation
Nation & Snowling (1998)
tested children’s ability to correctly read regular and irregular words:
- in isolation
- after hearing a sentence (related target)
results:
- dyslexic readers use context to process both regular and irregular words more than normal readers – i.e. 850ms quicker for regular words in context than in isolation
- context used more by normal readers for irregular than regular word reading
- greater priming effects in dyslexic readers than normal readers
- dyslexic readers use context more for regular words
semantic processing with dyslexia - semantic priming effects methodology
priming to measure semantic processing
stronger predictive processing and links between semantic concepts = larger semantic priming effects
calculated by subtracting reaction time for related and unrelated conditions
semantic processing with dyslexia - semantic priming effects study
van der Kleij et al (2019)
dyslexic readers show larger semantic priming effects than normal readers
rely on context
semantic processing and dyslexia - summary
Children with dyslexia may acquire stronger semantic processing ability to compensate for weaker phonological processing
The predictions in relation to the DRC model would be that, the use of contextual cues improves when the ‘non lexical route’ is impaired
