Reading difficulties Flashcards
1
Q
what are reading difficulties?
A
- encompasses range of diagnoses & cog/beh profiles
- dyslexia
- DLD
- poor comprehenders
- other reading difficulties or deficits
2
Q
dyslexia
A
- learning difficulty affecting skills involved in accurate & fluent word reading, and spelling (British Dyslexia Association, 2009)
- associated with a range of difficulties (Bedias et al., 2013) e.g. speed of word processing & these are broad at cog level
3
Q
who has dyslexia
A
- 9-12% of population (European Dyslexia Association)
- sim prevalence across ranges of IQ & SES: isn’t associated with social circumstance or general IQ
- more frequent in males - might be due to more variance in reading behs of males (Arnett et al., 2017) or that females better at masking symptoms possibly
4
Q
multi deficit model level of analysis
pennington (2006)
A
- aetilogical risk & protective factors
- neural systems = biological expression e.g. brain structure, comm between diff neural systems
- cog processes
- behavioural expression/disorders (also comorbidity & variability between disorders)
5
Q
pennington (2006)
further reading
A
- need for a measure deficit model arises partly from advances in understanding the complex genetics of behaviourally defined developmental disorders like dyslexia, ASD, ADHD
- emerging etiological model for developmental disorders e.g. dyslexia, is probabilistic & multifactorial
- prevailing cognitive model has been deterministic & often focused on a single cognitive cause e.g. phonological deficit as the cause of dyslexia
- potential contradiction in our explanatory frameworks for understanding developmental disorders
- resolve contradiction by presenting a multiple cognitive deficit model of developmental disorder
6
Q
genetic basis of dyslexia?
multi deficit model
A
- reading abilities appear to be heritable
- ~40-60% (Raskind et al., 2013)
- child at greater risk if parents have dyslexia (Schuite-Korne et al., 1996)
7
Q
stevenson et al. (1987)
genetic basis of dyslexia?
A
- studied 285 twin pairs
- heritability 29% for reading abilities
- 73% spelling abilities
all once intelligence was controlled for
8
Q
examples of candidate genes of dyslexia
A
- KIAA0319
- DCDC2
- DYX1C1
- ROBO1
- FOXP2
9
Q
KIAA0319 on chromosome 6p
candidate genes for dyslexia
A
- affects neural migration & radial glia adhesion - specialised cells involved in dev of nervous system
- v from genetic pooling of 223 ppts with DD (dyslexia) & 273 controls
- explanation of dyslexia at genetic level
(Cope et al., 2005)
10
Q
DCDC2 in DYX2 locus
candidate genes for dyslexia
A
- particularly associated with severe phenotype of dyslexia (Schumacher et al., 2006)
- longitudinal study found that genetic risk from DCDC2 strengthens the link between pre-reading maze learning & subsequent reading impairment (Gabel et al., 2021)
- this gene responsible for skills involved in finding a way around a maze but also reading showing particular skills helpful for learning to read
11
Q
pleiotropy
A
- one gene many effects
- not one-to-one mapping
- not on/off
- gene has multiple effects across multiple domains
12
Q
polygenicity
A
many genes contribute to a single trait
13
Q
generalist genes hypothesis
plomin & kovas (2005)
A
- genes for LD are same as those for normal variance
- genes for symptom A are same as those for symptom B
- genes for one LD are same for another LD e.g. dyslexia & ADHD
14
Q
how do genes influence dyslexia?
A
- high rates of comorbidity with other types of neurodiversity & psychiatric disorders
- genome-wide association study found associations between dyslexia risk & risk for ADHD, bipolar disorders & SZ (Gialluisi et al., 2021)
- genes interact with environment: higher influence when SES is high (Friend et al., 2008) in the expression of dyslexia
15
Q
dilnot et al. (2017)
A
- investigated risk factors for predicting att, beh & reading readiness in 251 children at risk of dyslexia (parent has dyslexia)
- home literacy env & child’s health predicted reading readiness
- home literacy env & family stresses predicted att & beh
- no main effect of family risk once environmental factors controlled for so heritability no longer predicting factor
16
Q
cog theories for dyslexia
A
- phonological deficit theory
- automisation hypothesis
- double-deficit theory
- magnocellular deficit theory
17
Q
phonological deficit theory
A
- deficit in phonological awareness
- e.g. ability to recognise spoken parts of sentences & words
- sounds same, rhyme patterns, repeated sounds (sc,sk), ability to segment between words, syllabic breakdown of words
18
Q
swan & goswami (1997)
phonological deficit theory
A
- groups: dyslexia, ‘poor readers’, CA control with typical reading ability, reading age MA (younger children)
- measured picture naming & phonological abilities
- picture naming: children with dyslexia poorer performance
- children with dyslexia performed similarity to reading-age controls for syllable & onset-rime measures
- children with dyslexia had poorer performance than reading-age controls for phonemic tasks
- both children with dyslexia & poor readers had better performance for high frequency words on the phoneme tasks
19
Q
automisation hypothesis
A
- dyslexia is as result of a deficit in automatic processing
- e.g. difficulty ‘automising’ reading behs once learnt
- might be caused by reduced activation in cerebellum
20
Q
moores et al. (2003)
automisation hypothesis
A
- ppl with dyslexia & controls took part in tasks that required focusing & shifting att between 2 target types (shapes and colours)
- dyslexia & control performance was sim for focusing att
- but dyslexia performed sig worse when relied on shifting att
- recog doesn’t appear to be automatic
- 2 hypotheses from this study - general resource deficit, automisation deficit
21
Q
general resource deficit
automisation hypothesis
A
inds with dyslexia lack the resources to perform well on the att-shifting task
22
Q
automisation deficit
automisation hypothesis
A
inds with dyslexia struggle to automise some skills, & therefore need more resources for these particular skills
23
Q
moores et al. (2003) investigating general resource deficit and automisation deficit
A
- normal & degraded stim (shapes)
- will increasing attentional load disproportionally affect the dyslexia group?
- dyslexia group weren’t uniquely affected by degraded stim
- suggests a general lack of resources doesnt explain performance diffs
- could be explained by an automisation deficit
24
Q
double-deficit theory
badain (1997)
A
- phonological awareness
- rapid naming
- 3rd orthographic deficit?
25
Q
single deficit models
A
- 1 to 1 relationship between bio factors or cog deficits & presentation of the disorder
- e.g. trying to find a singular ‘core’ explanation for dyslexia that fits every diagnosis
26
Q
multiple deficit models
A
- complex etiology
- shared & independent factors contributing to a cog skill
- genes have a probablistic influence (not on/off)
- pennington & bishop (2009)
27
Q
explanations of comorbidity
A
- one diagnosis increases likelihood of receiving another diagnosis
- shared liabilities - could have a genetic, cog, or cellular basis
- correlated liabilities - associated but distinct risk factors
28
Q
comorbidity within dyslexia
A
- DLD (Catts et al., 2005)
- ADHD (Gilger et al., 1992)
- developmental dyscalculia (Landerl & Moll, 2010)
- developmental coordination disorder (Kaplan et al., 1988)
29
Q
snowling et al. (2019)
A
- family risk of dyslexia or DLD vs TD controls
- observed before entering school (t1,t2) & during school (t3-5)
- measured range of cog predictors
- classified in year 3 of school into disorder groups
- severity changes over time
- poor lang as preschool precursor of deficits
- dyslexia & DLD show diff dev trajectories
- more severe phonological deficits in comorbid cases
- motor & EF deficits as a marker of wider neural deficits (corr but unrelated to lang performance)
- improvements in lang dev in comorbid group could be protective
- very important to examine influence of time on outcomes
30
Q
why does comorbidity occur between dyslexia & other neurodev disorders?
A
- shared genetic etiology
- shared cog bases
- ev points towards sim underlying mechanisms rather than causality (van Bergen, 2023)
31
Q
evidence based interventions
A
- theory of how a skill develops
- theory of how a skill is promoted
- high quality evidence
snowling & hulme (2011)
32
Q
theory-based interventions
A
- theories inform which skills are targeted by the intervention
- e.g.:
- phonological deficit theory identifies phonemic awareness as a key skill
- intervention based on isolating, identifying & blending phonemes
33
Q
review of phonologival awareness training
A
- effect sizes reported by the national reading panel (NICHD, 2000)
- 0.86 on phonological awareness
- 0.53 on reading outcomes
- 0.59 on spelling outcomes
- highly effective across literacy domains
- not effective outside domain e.g. maths
- improved in combination with letter knowledge intervention
34
Q
theory of how a skill develops
A
- ev reviewed to see how a skill is best promoted
- e.g. phonics instruction can be used to improve letter-sound knowledge
- different techniques: synthetic phonics, analytic phonics
- both focus on segmenting & understanding words but do this in different ways
- both techniques useful, but combined approach with synthetic phonics instruction appears most successful
35
Q
high quality evidence
A
- rigorous trials
- educationally realistic trials - able to implement them, reflect types of behs appropriate to classroom & ind
- randomised controlled trials
- scaled up classroom research - approaching interventions which are realistic to which they would be implemented and that which would be most helpful
36
Q
things to consider
A
- cost of intervention - realistic and affordable
- implementing into educational settings - e.g. how long does it take?
- accommodating for inds with reading difficulties if interventions aren’t successful - relates to variability in behavioural phenotype of dyslexia, comorbidity. What are the other options?
37
Q
snowling & hulme (2011)
further reading
A
- decoding difficulties appear to be caused by problems with phonological (speech sound) processing
- any well-founded educational intervention must be based on a sound theory of the causes of a particular form of learning difficulty, which in turn must be based on an understanding of how a given skill is learned by TD children
- phonologically based interventions are effective in ameliorating children’s word level decoding difficulties
- smaller evidence base showing that reading & oral language (OL) comprehension difficulties can be ameliorated by suitable interventions to boost vocabulary and broader OL skills
