Dyslexia

Question 1

how does the DSM-5 describe Dyslexia?

Answer 1

an alternative term used to refer to a pattern of learning difficulties characterised by problems with fluent or accurate word recognition, poor decoding and poor spelling abilities (Lyton, 2003)

Question 2

how many people is dyslexia thought to affect

Answer 2

3-6 % with more boys than girls being affected (Rutter et al., 2004)

Question 3

What is the prevalence of Dyslexia like worldwide?

Answer 3

there is a lot of vairance worldwide:
- Countries use different cut offs
- the structure of language can determine, with languages containing shallower orthography such as Spaish or Fnnish being easier to learn (Seymour et al., 2003).

Question 4

What are the pre-school symptoms that define dyslexia?

Answer 4

delayed speech development
speech problems
little appreciation of ryming words
difficulty learning the alphabet

Question 5

What are the school age symptoms of dyslexia

Answer 5

Problems learning names and sounds of letters
unpredictable and inconsistent spelling
confusing the order of letters in words
making errors when reading out loud
struggling to learn sequences
poor handwriting
taking longer to complete written work

Question 6

Why do other diagnosis have to be ruled out when diagnosising someone with Dyslexia?

Answer 6

because issues such as vision and hearing may impact learning
also there is a high comorbidity with ADHD (Boada et al., 2012) and language impairment and speech disorder which is thought to be mediated by shared etiologic and cognitive factors (Peterson and Pennington, 2015)
COuld impact child’s ability to learn and so would show similar symptoms

Question 7

what are the steps involded in dyslexia diagnosis?

Answer 7

parents and teachers are asked to provide general information
children are asked to perform a set of cognitive tasks

Question 8

overall what is a key characteristic for the diagnosis of dyslexia?

Answer 8

If reading and writning age is lower compared to what is expected for chronological age, education and IQ

Question 9

What is the active gene-enviroment correlation?

Answer 9

It explains how genetic differences change sensitivity to particular environmental effects.
e.g. in dyslexia children choose an environment based off their genotype (avoid reading)
Research has shown the heritability of dyslexia increases as parents education level and socioeconomic status increases.

Question 10

describe twin studies for dyslexia

Answer 10

Dyslexia has been shown to run in families
Twin studies show concordance rates with MZ twins higher than DZ showing a genetic basis (De Fries et al ., 1987)

Question 11

What has linkage anaysis found for dyslexia?

Answer 11

Multitudes of genes that may be related to dyslexia
although we cannot be sure if these genes interact with the environment.
Genetic differences have shown to contribute more to high IQ dyslexia withthis occurring in children from higher economic status families (Peterson and Pennington, 2015)

Question 12

What is the brain phenotype seen in dyslexia?

Answer 12

Darki et al (2012) found that reductions in the left hemisphere white matter volume was significant for variation for three of the risk genes identified in the linage analysis.
These findings being in a typical population were also consistent with dyslexia as a continuous not categorical disorder.

Question 13

What are the risk genes for dyslexia thought to do?

Answer 13

alter brain development in the left hemisphere and therefore alter speech development and language development to make acquisition of written language more difficult.

Question 14

Explainthe brain structure of individuals with dyslexia

Answer 14

they have been found to show less structural a symmetry than typically developing brains

Question 15

What did Grigorenko et al (2001) study find about a symmetry in dyslexic brains

Answer 15

studied 20 dyslexics and 20 controls
Structural MRI measuring brain size
the planum temporal (used in language processing) was a lot smaller

(there is a large range of variation in this area and and the study did not control for other factors such as different levels of exposure)

Question 16

Explain Brunswick (1999) study on brain imaging tasks

Answer 16

Found less activation in the left inferior and medial temporal lobe, left fronal operculum and cerebellum in those who are dyslexic

Question 17

Why is dyslexia higher in low socioeconomic backgrounds?

Answer 17

could be due to:
less practise of literacy based activities at him
Higher status have been shown to read more at home.
schooling can also have a substantial impact on reading and spelling ability

Question 18

What is phonological processing?

Answer 18

The ability to break down words into their individual sounds

Question 19

Outline the theory of phonological deficits?

Answer 19

Dyslexic people have a specific impairment in the representation, storage, and / or retrieval of speech sounds
where speech sounds are poorly represented

Question 20

What did Hulme and Snowling (2009) say about phonological deficit theory

Answer 20

Phonological deficits are a difficulty in the representation of speech sounds
The more severe the deficit the more marked symptoms of dyslexia.
Dyslexic children struggle to become fluent in matching knowledge of word sounds to written words.

Question 21

What did SNowling et al (2019) say to define phonological deficit theory?

Answer 21

Problems with phonology lead to diffiultys in learning mappings between orthography and phonology and other difficulties which include problems learning new spoken words, poor verbal STM and problems with word retrieval and picture naming.

Question 22

What are the supporting points for phonological deficit theory?

Answer 22

Mostly comes from evidence that people process speech sounds slowly:
- Baddley Bryant (1983): phonological skills age four predict reading age 8
- Snowling and Hulme (1991): poor at phonological tasks
- Hulme (1981) rules out other deficits

Question 23

Elaborate on why Baddley and Bryant (1983) supports phonological deficit theory of dyslexia

Answer 23

got children to complete phonological tasks at age 4
Did not require explicit attention, or manipulation of phenomes, including categorical speech perception etc.
FOund that phonological skills at age four could predict reading age at age 8 even when controlling for IQ and social status.

Question 24

Explain in more detail why Snowling and Hulme (1991) study supports phonological deficit theory of dyslexia

Answer 24

48 dyslexics, 48 conrols
Given a battery of phonological tasks (rhym detection, phenome segmentation, phenome blending)
CHildren with dyslexia made more errors and took more time to complete the task.

Question 25

Explain why Hulme (1981) study provides evidence for phonological deficit theory

Answer 25

THey are able to rule othe other factors as through a number of tasks showed that dyslexic individuals only had deficits in verbal STM but not visual STM showing the issue is phonological in nature.

Question 26

What are an overview of the criticisms of phonological deficit theory of dyslexia?

Answer 26

• Dickiee et al (2013) dyslexic adults perform normally on phonological tasks
• Boots and Colliugues (2013) brain imaging study
• not nessarry or sufficient to account for dyslexia
• Sakida et al (2016) people don’t always sucom to dyslexia

Question 27

Explain Boots and colligues (2013) study to criticise phonological deficits

Answer 27

nuroimmaging sudy on brain resopsonses to phonetic contrasts in the primary and secondary cortex
found responses were similar in dyslexics and non dyslexics.
found structural and functional connectivity issues in individuals with dyslexia arguing these findings are consistent with “intact but less acessable phonetic representations”
Meaning phonological deficits may not be as the theory explains

Question 28

Explain the criticism that phonological deficits is not sufficient to explain dyslexia

Answer 28

Phonological deficits are neither necessary or sufficient to account for dyslexia (Pennington, 2006)
Critics don’t deny phonological deficits instead explaining that it is much more extended in its roots in general sensory motor and learning processes Ramus et al (2003)

Question 29

what was Saksada et al ., 2016 criticism of phonological deficit theory

Answer 29

Many childre at a family risk of dyslexia do not succumb to reading difficulties but also have problems with phonological awareness as ell as this many individuals have deficits outside of the phonological realm.

Question 30

Explain peterson et al 2014 criticism of phonological theories of dyslexia.

Answer 30

Most poor readers demonstrate poor phonological skills but this is not very explanatory as many dyslexic people do not display phonological problems so it is hard to distinguish from people who complain of visual problems.

Question 31

What are magnocellular pathways?

Answer 31

Visual pathways which comprise of large cells responsible for detecting contrast motion and rapid changes in the visual field.
The system rapidly focuses ventral steam attention on the letter identified an sequences them by logging the amplitudeand order of shifts of attention and eye movements made during each word.

Question 32

Explain why magnocellular thoeory causes deficits in dyslexia

Answer 32

there is a deficit in magnocellular system reduced sensitivity creates difficulty suppressing visual information.
retaal images persist longer than is appropriate resulting in an excess of visual information that creates a masking effect and reduction in visual activity (Stein 2019)

IT explains why children are slower at recognising individual letters and sequencing them correctly compared to good readers

Question 33

What are the supporting points for MAgnocellualar theory

Answer 33

• it is able to describe all of the deficits through one biological cause
• Stein (2019) flicker fusion task
• Jarabokva et al (1995) can explain comorbidity
• Crildo-Chika et al., (2015) empirical evidence

Question 34

Explain Stein (2019) support for magnoellular theory

Answer 34

dyslexic people show a significantly slower response in the flicker fusion task
Torch is shone on and off until a continuous image
Dyslexia people show reduced sensitivity in this task and therefore have a higher threshold (doesn’t need to blink at as fast rates)

Question 35

Explain why Jarabkova et al (1995) supports magnocellular theory

Answer 35

Magnocellular neurones are found throughout the CNS. They are all characterised by their expression of specific surface signature molecules recognised by antibodies suh as CAT301. This explains why there is a strong association between dyslexia and autoimmune conditions such as allergies, asthma and eczema

Question 36

Explain why Galabrurda et al (1985) study provides support for magnocellular theory

Answer 36

Studied post mortem brains and found lear abnormalities affecting the language area in the left hemisphere.
Also found magnocellular layers to be about 40% smaller and more disorganised

Question 37

how did Grildo-CHika et al (2015) provide support for magnocellular theory

Answer 37

in 16 dyslexics found magnocellular layers were significantly thinner than age matched conrols

Question 38

what are some of the criticisms of magnocellular theory

Answer 38

• highly controversial Stein (2012)
• cannot be used in treatment due to lack of evidence
• correlation doesn’t equal causation

Question 39

explain why magnocellular theory is highly controversial

Answer 39

Stein (2012) suggested that 90% of studies posted since 2000 have found a link in support however this has been disputed due to publication bias

Question 40

Why can magnocellulalr theory not be useful in interventions

Answer 40

The aerican acaemy of pediatrics (2009) concluded that “given the contrasting findings in literature possible magnicellular deficit has insufficient evidence on what to base treatment” so although the theory is there it cannot help treatment options

Question 41

explain the correlation does not equal causation part of magnocellular theory

Answer 41

REduced M cell activity coul be irrelevant to reading ability we do not know yet if the two are related

Question 42

Provide an overview of interventions for individuals with dyslexia

Answer 42

most interventions offer extra support and instruction on areas such as phonemic awareness, phonics, spelling writhing and fluency, vocabulary and comprehension.

Coloured filters have also been found to be useful thought to enhance M cell functioning

Question 43

Explain Galuschka et al (2020) study on interventions for dysleixa

Answer 43

investigated 34 control trials that evaluated spelling interventions in dyslexic people in a range of ages.
the most successful treatment approaches were the ones that use phonics, orthographic and morphological instruction which was able to have a intermediate to high impact on spelling performance

Question 44

Explain Friths (1985) research on interventions for dyslexia

Answer 44

theorised people gain an ability to spell and read when they realise graphines become phenomesand begin self teaching.
Interventions primarily focused on helping this acquisition called ‘phonics intervention’ and a large body of evidence supports this (Galuschka et al., 2014)

(however it doesn’t work for every type of work and is not very applicable to other languages)