Slides from talk at British Dyslexia Association in 2008

1. Treating reading disability
without reading: evaluating
alternative intervention
approaches
Dorothy Bishop
University of Oxford
1

2. 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
2

3. 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
3

4. 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
4

5. Goals of this talk
• Identify some questions for parents
considering a new treatments
• Illustrate with Dore method and fish oil
5

6. How to measure reading
– a brief digression
6

7. How to measure reading etc.
70
60
50
words read
40
30
20
10
0
5 6 7 8 9 10 11 12 13 14 15
age (yr)
A 9-year-old reads 20 words
Reading Age is 8 years: Sounds bad: 12 months behind age level
7

8. Reading age misleading: does not take into
account spread of scores at a given age;
non-linear relation with chronological age
80
70
60
words read
50
40
30
20
10
0
5 6 7 8 9 10 11 12 13 14 15
age (yr)
A 9-year-old reads 20 words. Error bars show middle 50% of children
Within normal range for children of this age
8

9. Better to measure reading in terms of
statistical abnormality at that age
80
70
60
words read
50
40
30
20
10
0
5 6 7 8 9 10 11 12 13 14 15
age (yr)
Percentile: % of children of this age obtaining this score or lower;
Also z-score or standard score: different way of expressing same idea 9

10. 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?
10

11. 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 11

12. 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)
12

13. 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
13

14. 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
14

15. 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 15

16. 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)
16

17. 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
Duncan Goodhew 17
Kenny Logan Greg Louganis Paul Nixon

18. Questions
1. 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
18

19. Does evidence for efficacy goes
beyond testimonials?
One published study on Dore intervention
• Two papers in Dyslexia reporting different
phases
19

20. 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 20

21. 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
21

22. Data from school-administered
tests, treated group only
% improvement
calculated by dividing
orange line by pink
NFER group reading test line, i.e. change from time
2 to 3, divided by change
144
from time 1 to 2
132
120 reading age Conclude “reading age
108 actual age increased 3 times”
96
84 But misleading: depends
-15 -3 9 21 on low score at time 2
time relative to intervention start (mo)
Why use „reading age‟
when test has scaled
22
scores?

23. 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) 23

24. Q3. Is there evidence that gains
are due to treatment?
24

25. 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) 25

26. 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
26

27. 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
27

28. 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 28

29. Regression to the mean
3
8
2
6
1
average score
4
score
2 0
0 -1
-2
-2
-4
-3
-6
-4
1 2
1 2
test occasion
test occasion
Correlation between time 1 and time 2 = .06
29

30. Regression to the mean
3
2
1.5 2
1
average score
1
0.5
score
0
0
-1
-0.5
-1 -2
-1.5 -3
-2
-4
1 2 1 2
test occasion test occasion
Correlation between time 1 and time 2 = .99
30

31. Regression to the mean
4 3
3 2
2
average score
1
score
1 0
0 -1
-1
-2
-2
-3
-3
-4
1 2 1 2
test occasion test occasion
Correlation between time 1 and time 2 = .76
“Social scientists incorrectly estimate the effects of ameliorative
interventions.....and snake-oil peddlers earn a healthy living all
because our intuition fails when trying to comprehend regression
toward the mean” (Campbell & Kenny, 1999)
31

32. 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
32

33. 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.
33

34. Dore study did include
untreated control group
34

35. 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
35

36. Significant group differences in gain on bead
threading, semantic fluency and reading
Control group Treated Group
time 2 time 1 time 2 time 1
Post Stability Post Stability
Bead thread Bead thread
Semantic Fl Semantic Fl
Verbal Fl. Verbal Fl.
Backward digits Backward digits
Phon segment Phon segment
RAN RAN
One min writing One min writing
Nons pass reading Nons pass reading
Spell Spell
Read Read
0 2 4 6 8 10 0 2 4 6 8 10
mean decile mean decile
36

37. 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)
37

38. Results on dyslexia screening test, time 1 and time 4
N.B. No control data – both groups now treated
GroupD Group I
Post Stability Post Stability
Bead thread Bead thread
Semantic Fl Semantic Fl
Verbal Fl. Verbal Fl.
Backward digits Backward digits
time 1 time 1
Phon segment Phon segment
time 4 time 4
RAN RAN
One min writing One min writing
Nons pass reading Nons pass reading
Spell Spell
Read Read
0 2 4 6 8 10 0 2 4 6 8 10
mean decile mean decile
Note:
lack of “stunning” progress on literacy tests
38

39. 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
39

40. Costs in relation to benefits
Cost 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
40

41. Fish oil
41

42. 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
42

43. 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
43

44. 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
44

45. 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
45

46. 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
46

47. 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
47

48. 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 48

49. Q3. Is there evidence that gains
are due to treatment?
• Inclusion of control group makes it
possible to take into account
practice, maturation, etc.
49

50. Q4. Are costs reasonable?
• around £19.50 for 60 capsules (1 per day)
• Treatment may need to be „long term‟
• £118 per year
50

51. Barriers to objective evaluation
• Failure to recognise important effects of :
– expectations
– maturation
– practice
– statistical artefact
51

52. Human tendency to be
impressed by testimonials
N.B. Testimonials problematic because
• selective
• often at odds with objective evaluation
52

53. Human tendency to think
something that has taken
time/effort/money was
worthwhile
53

54. 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. 54

55. Human tendency to be
impressed by neuroscientific
explanations
55

56. “The seductive allure of
neuroscience explanations”
Weisberg et al. 2008. J. Cognitive Neuroscience 20: 470-7
without neuroscience with neuroscience
1.5
People given explanations 1
of psychological phenomenon
satisfaction
0.5
that were accepted or vacuous
0
and judged if satisfactory.
“With neuroscience” just added
-0.5
phrases such as “brain scans -1
indicated” and “because of -1.5
the frontal lobe circuitry involved” good explanation bad explanation
56

57. 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
57

58. Dorothy Bishop
Oxford Study of Children’s
Communication Impairments,
Department of Experimental Psychology,
South Parks Road,
Oxford,
OX1 3UD,
England.
for reading list see:
http://www.psy.ox.ac.uk/oscci/
58
Photography: Biljana Scott