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Treating reading disability without reading: evaluating

alternative intervention approaches

Dorothy BishopUniversity of Oxford

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Conventional approaches to dyslexia

• Most children have problems with “phonological awareness”

• Interventions focus on training children to identify sounds in words and relate these to letters

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Problems with conventional approach

– Intensive and prolonged phonological intervention can be effective in improving reading accuracy

– Reading fluency remains a problem– Methods that are effective for most children,

don’t work for all: A hard core of children remain very hard to treat

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Neuroscience studies of developmental disorders

The Holy Grail

Develop a theory of the disorder that not only explains why it occurs, but also

motivates effective intervention

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Goals of this talk

• Identify some questions for parents considering a new treatments

• Illustrate with Dore method and fish oil

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How to measure reading – a brief digression

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How to measure reading etc.

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A 9-year-old reads 20 wordsReading Age is 8 years: Sounds bad: 12 months behind age level

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Reading age misleading: does not take into account spread of scores at a given age; non-linear relation with chronological age

A 9-year-old reads 20 words. Error bars show middle 50% of childrenWithin normal range for children of this age

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Better to measure reading in terms of statistical abnormality at that age

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Percentile: % of children of this age obtaining this score or lower;Also z-score or standard score: different way of expressing same idea

Beware of studies that rely on “reading age”:

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Some questions to ask of a new treatment

1. Is the theory scientifically plausible?2. Does evidence for efficacy goes beyond

testimonials? – have studies been done with groups for whom treatment is recommended?

3. Is there evidence that gains are due to treatment rather than maturation, practice, placebo, etc.?

4. Are costs reasonable relative to benefits?

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Dore method: what is it?• Method for curing

cerebellar problems developed by Wynford Dore to help his dyslexic daughter

• Individualised program of exercises, done for around 10 mins, 2 x per day, assessed every 6 weeks

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Dore method: the exercises• Hundreds of exercises, e.g.:

– standing on a cushion on one leg and throwing a beanbag from one hand to another for one minute

– hopping on one leg in large circle, clockwise then anticlockwise

– sitting upright in a chair, turning head from side to side, pausing to focus on chosen point

– balancing on a wobble board(Examples only: full details confidential because

commercially sensitive)

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Dore method: the theory• Dyslexia and other

learning difficulties arise when the cerebellum fails to develop normally

• Cerebellar impairments differ from person to person but can be diagnosed by specific tests of mental and physical co-ordination

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Cerebellar theory of dyslexia

• Not proven, but some evidence for it• Brain imaging and neuroanatomical

studies offer some support• Theory that dyslexia involves failure to

automatise skills is plausible• Associated deficits in motor co-ordination

in a subset of people with dyslexia

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Previous research on effectiveness of motor training

• Training can improve performance on motor tasks, e.g. juggling

• In rats, exercise can reverse cerebellar deficits caused by prenatal alcohol or zero gravity

• But no evidence that motor training enhances development of non-motor skills

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The Theory: evaluation

• Notion that training motor skills will have effect on other skills:

• “This hypothesis required something of a leap of faith, in that it is generally believed that the cerebellum comprises a very large number of independent ‘cerebro-cortical microzones’, and so it is not clear why training on one sort of task should generalize to unrelated tasks”

(Reynolds et al, 2003, p 53)

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The Theory: evaluation• If training focusing on one region of cerebellum

had general effects on all cerebellar functions, then – activities like juggling and skateboarding should

protect against dyslexia– sportsmen and women should have low risk of

dyslexia

Paul NixonKenny Logan Greg LouganisDuncan Goodhew

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Questions1. Is the theory scientifically plausible?

• Notion that cerebellum may be implicated in dyslexia is plausible though not proven

• Notion that motor exercises will have beneficial effect on regions of cerebellum concerned with learning is considerably less plausible

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Does evidence for efficacy goes beyond testimonials?

One published study on Dore intervention• Two papers in Dyslexia reporting different

phases

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Have studies been done with groups for whom treatment is

recommended?• 2003 study: 296 children from 3 school yrs• Selected 35 “at risk” on basis of Dyslexia

Screening Test : strong risk in 34%, mild in 21%, remainder fall below ‘at risk’ level

• Divided randomly into untreated and treated groups

• Previous diagnoses:– treated: 4 dyslexic, 1 dyspraxic– control: 2 dyslexic, 1 dyspraxic, 1 ADHD

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Results as reported by Dore organisation

• Dore (2006): results were “stunning” and:

– reading age, increased 3 x– comprehension age: increased almost 5 x– writing, increased by “an extraordinary” 17 x

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Data from school-administered tests, treated group only

% improvementcalculated by dividingorange line by pinkline, i.e. change from time2 to 3, divided by changefrom time 1 to 2

Conclude “reading ageincreased 3 times”

But misleading: dependson low score at time 2

Why use ‘reading age’when test has scaledscores?

NFER group reading test

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time relative to intervention start (mo)

reading age

actual age

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Data from SATS (treated children only)“Designed for assessment of attainment rather than

psychometric rigour” (Reynolds & Nicolson, 2007)• Level 2: average for typical 7 yr old• Level 3: average for typical 9 yr old• Level 4: average for typical 11 yr old

“One should not over-interpret these data”(Reynolds & Nicolson, 2007)

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Q3. Is there evidence that gains are due to treatment?

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Uninteresting reasons why scores may improve - 1

• Maturation–Children change with age–Shoe size may go up after treatment, but

does not mean that treatment made feet bigger

• Not an issue if age-adjusted scores used but problematic if reliant on ‘reading age’ or tests with no age norms (e.g. balance tests)

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Uninteresting reasons why scores may improve - 2

• Placebo effect / effect of other intervention

–Child may be having other help or may respond to increased attention

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Uninteresting reasons why scores may improve - 3

• Practice effects• Child does test better 2nd time around

because they have done it before

• Numerous examples in research literature: e.g. Dyslexia Screening Test manual recommends that ‘semantic fluency’ subtest is not valid if given twice because children tend to practice once they have done the test

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Uninteresting reasons why scores may improve - 4

• Regression to the mean– Statistical artefact whereby someone

selected for extreme score at time 1 will on average have less extreme score at time 2

“Regression to the mean is as inevitable as death and taxes”Campbell & Kenny (1999) A primer on

regression artefacts

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Regression to the mean

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Regression to the mean

Correlation between time 1 and time 2 = .99

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Regression to the mean

Correlation between time 1 and time 2 = .76

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“Social scientists incorrectly estimate the effects of ameliorativeinterventions.....and snake-oil peddlers earn a healthy living all because our intuition fails when trying to comprehend regressiontoward the mean” (Campbell & Kenny, 1999)

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These unwanted sources of change can be identified if we have a CONTROL GROUP

• Untreated matched group given same pre- and post-test will control for:– Maturation– Effects of other intervention– Practice effects– Regression to the mean

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Alternative treatment control group

• Crucial to see if improvement due to:• Placebo/expectation effects

–Child, parent, teachers all expect and want to see gains

–Child gets more attention, boosted confidence, etc.

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Dore study did include untreated control group

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Results: total on dyslexia screening

• High score indicates more risk• NB score include bead-threading/posture

• Treated: mean fell from 0.74 to 0.34– “strong risk” fell from 33% to 11%

• Control: mean fell from 0.72 to 0.44– “strong risk” fell from 35% to 24%

Everyone improves, even if not treated

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Significant group differences in gain on bead threading, semantic fluency and reading

Control group

0 2 4 6 8 10

Read

SpellNons pass reading

One min writingRAN

Phon segmentBackward digits

Verbal Fl.

Semantic FlBead thread

Post Stability

mean decile

time 2 time 1

Treated Group

0 2 4 6 8 10

Read

SpellNons pass reading

One min writingRAN

Phon segment

Backward digitsVerbal Fl.

Semantic FlBead thread

Post Stability

mean decile

time 2 time 1

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Control group subsequently given the treatment

• Results published in Dyslexia journal in 2007

• Control group now known as group D (delayed intervention), and compared with original intervention group (I)

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Group I

0 2 4 6 8 10

Read

Spell

Nons pass reading

One min writing

RAN

Phon segment

Backward digits

Verbal Fl.

Semantic Fl

Bead thread

Post Stability

mean decile

time 1

time 4

GroupD

0 2 4 6 8 10

Read

Spell

Nons pass reading

One min writing

RAN

Phon segment

Backward digits

Verbal Fl.

Semantic Fl

Bead thread

Post Stability

mean decile

time 1

time 4

Note: lack of “stunning” progress on literacy tests

Results on dyslexia screening test, time 1 and time 4N.B. No control data – both groups now treated

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Is there evidence of gains due to treatment?

• Improvement looks best for measures where there is no control data

• On reading measures where control group available, initial gain in the treated group on reading was small and not sustained

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Costs in relation to benefitsCost of treatment is around £1700-£2000:“ Surely it is a price worth paying in the attempt to

transform the life of your child so that they are able to enjoy school, to develop social skills, to develop good sporting skills, to have good prospects in life?”

Dore (2006) p. 171

“Money-back guarantee”But only if “no physiological change” – i.e. child

who improves on balance/eye tracking won’t get refund, even if dyslexia/ADHD etc unchanged

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Fish oil

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The theory

• Certain highly unsaturated fatty acids (HUFAs) important in brain development and neuronal signal transduction

• Brain function may be affected by:– Dietary insufficiency– Genetic abnormality in phospholipid

metabolism • Administration of HUFAs may improve

synaptic transmission

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Evidence of abnormal fatty acid levels in dyslexia

• Clinical signs of fatty acid deficiency* found in adults with dyslexia (Taylor et al, 2000)

• Clinical signs of FAD correlate with severity of dyslexia in males only (Richardson et al, 2000)

* 7 items including dry skin/hair/nails, excess thirst, frequent urination

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Evidence from treatment trials

• Significant reduction in ADHD symptoms in children with comorbid dyslexia/ADHD cf. placebo (Richardson & Puri, 2002)– reading not assessed (!!??)

• Cf. no improvement of ADHD symptoms vs. placebo in 2 studies of ADHD, though studies vary in fatty acid, sample, etc– Hirayama et al. 2004– Voigt et al. ,2001

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Evidence from treatment trials

• Oxford-Durham study on children with developmental coordination disorder; Treated show significantly more improvement in literacy (reading age!) and ADHD symptoms: (Richardson & Montgomery, 2005)

• Requests to see raw data to identify children with dyslexia from this sample get no response

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Controlled trial of fish oil in dyslexic adults

• Cyhlarova et al, 2007 report baseline results - no differences in membrane fatty acid levels between dyslexic and control adults, though ratio of types of fatty acid differs

• Requests for information on progress of this treatment trial get no response

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Q1. Is the theory scientifically plausible?

• Membrane phospholipid deficiency: speculative theory developed to account for schizophrenia, extended to neurodevelopmental disorders

• Most plausible when applied to children who show physical symptoms suggestive of essential fatty acid deficiency

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Q2. Does evidence for efficacy goes beyond testimonials? – have studies been done with groups for whom treatment is

recommended?• Several clinical trials but only one

specifically on children with dyslexia (and ADHD) - did not look at reading outcomes

• Study of developmental coordination disorder included measures of reading as part of outcome assessment

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Q3. Is there evidence that gains are due to treatment?

• Inclusion of control group makes it possible to take into account practice, maturation, etc.

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Q4. Are costs reasonable?

• around £19.50 for 60 capsules (1 per day)• Treatment may need to be ‘long term’• £118 per year

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Barriers to objective evaluation

• Failure to recognise important effects of :– expectations– maturation– practice– statistical artefact

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Human tendency to be impressed by testimonials

N.B. Testimonials problematic because

• selective• often at odds with objective evaluation

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Human tendency to think something that has taken

time/effort/money was worthwhile

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Trial of Sunflower therapy• Includes applied kinesiology, physical

manipulation, massage, homeopathy, herbal remedies and neuro-linguistic programming

• Similar gains in test scores for clinical and control children

• Higher academic self-esteem in those undergoing treatment

• 57% of parents thought Sunflower therapy was effective in treating learning difficulties

Bull, L. (2007). Sunflower therapy for children with specific learning difficulties (dyslexia): A randomised, controlled trial. Complement Ther Clin Pract, 13, 15-24.

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Human tendency to be impressed by neuroscientific

explanations

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“The seductive allure of neuroscience explanations”

Weisberg et al. 2008. J. Cognitive Neuroscience 20: 470-7

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without neuroscience with neuroscience

People given explanationsof psychological phenomenonthat were accepted or vacuousand judged if satisfactory.“With neuroscience” just addedphrases such as “brain scansindicated” and “because of the frontal lobe circuitry involved”

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Conclusions• Finding the neuroscientific basis of dyslexia is an

important goal• However, we are a long way from having reached that

goal • Even when we reach it, it may not be obvious how to

translate knowledge into intervention• We need to adopt as critical an approach

neuroscientific explanations as we do to other aspects of dyslexia research; claims that neuroscientific treatments are superior to conventional treatments are not, in our current state of knowledge, supported

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Dorothy BishopOxford Study of Children’sCommunication Impairments,Department of Experimental Psychology,South Parks Road,Oxford,OX1 3UD,England.

for reading list see:

http://www.psy.ox.ac.uk/oscci/

Photography: Biljana Scott