Memorandum submitted by Professor Julian
Elliott (LI 33)
A key difficulty that surrounds the use of evidence
in respect of dyslexia is not that there is a dearth of high quality
research studies operating at different levels of analysis, ranging
from genetics to neuroscience, to cognitive and educational psychology,
to classroom practice. Rather, it is the weakness in progressing
from one level of analysis to the next, and the misconceptions
and misunderstandings that result, which are highly problematic.
I try to represent this difficulty by producing a general proposition
that would seem to represent the most widely held understandings
held by the general public and by many education and medical practitioners.
2. GENERAL PROPOSITION
Among the wider population of people with reading
and other literacy difficulties, there is a subset that has a
condition called dyslexia. Genetic and brain functioning studies
have secured the argument that this condition has a biological
basis. Dyslexia can be identified by clinicians on the basis of
specialized tests and assessments. Having diagnosed that an individual
is dyslexic, it is then possible to set in train intervention
programmes that are geared to remediate the individual's problem.
These programmes differ significantly from best practice for "non-dyslexic"
poor readers. Failure to recognise the condition is likely to
result in incorrect forms of intervention (or no intervention)
and ultimately, unrealized potential.
It is possible to unpick the validity of this
widely held view by considering each of the links in this claim.
This can be achieved by examining a series of specific propositions
that, cumulatively, underpin the logic of the general claim above.
3. SPECIFIC PROPOSITIONS
3.1 Many individuals experience reading
difficulties for reasons other than bad teaching, adverse home
environment, poor motivation, emotional factors, or severe sensory/physical/mental
Comment: This seems be incontrovertible
although contrary claims can be found from time to time.
3.2 For this group, the origin of their
reading problems is essentially biological. Genetic factors result
in a predisposition or susceptibility to reading failure. The
realisation of this failure depends significantly upon environmental
factors. This interaction means that searching for a direct genetic
link to reading difficulty is unlikely to prove successful. However,
this does not rule out the promise of important gains for understanding
and intervention in the future.
Comment: This again is incontrovertible.
3.3 This underlying biologically-based reading
problem can be labelled "dyslexia". Dyslexia can be
understood as a reading difficulty that has a genetic basis (or,
more accurately, genetic bases, as these are likely to be multiple
Comment: While appropriate for scientific
research, this precept cannot translate directly into clinical
practice as there is currently no clear genetic test that can
be employed to make a differential diagnosis for any given individual.
3.4 This genetic predisposition has often
been held to be linked to problems relating to phonological factors.
Comment: Even proponents of the phonological
theory (eg Torgesen and Snowling) accept that this does not offer
a full account There are different accounts of biological foundations
of dyslexia and there are likely to be different genetic bases
of these foundations.
3.5 Reading disability has been held to
affect 20% of the population (Shaywitz, 2003). Estimates of dyslexia
range from 5% to 15%+.
Comment: Is the there a biological difference
between the dyslexic group and a larger reading-disabled group?
How does one reconcile these differing estimates with the tendency
of some writers (such as Shaywitz, Wagner) to treat reading disability
and dyslexia interchangeably? Is it likely that a relatively high
proportion of the population has a genetic problem that underpins
3.6 Dyslexia involves more than decoding
and it is likely that the problem transforms itself; from reading
slowly to making spelling errors, to having difficulty comprehending.
In addition, other weaknesses, not directly related to reading
(eg planning and organising oneself) are sometimes seen as a form
of dyslexia even if the individual's literacy skills are only
Comment: As the range of difficulties
that are seen as characterising dyslexia increases, the proportion
of the population with the condition expands to the point that
the diagnosis becomes meaningless and practitioners increasingly
respond in a cynical and unsympathetic fashion. Where should one
draw the line?
3.7 The shift from structural to functional
brain studies has resulted in greater understanding of those areas
of the brain involved in reading. "Dyslexics" demonstrate
reduced activation in some of these areas and hyperactivation
Comment: These studies typically contrast
brain functioning in good and poor groups of readers. They do
not differentiate a dyslexic subgroup from within a broader population
of individuals with reading difficulties. Thus, it is ingenuous
to suggest that brain imaging techniques have diagnostic utility.
Currently, one cannot yet use fMRI with individuals for clinical
(diagnostic or intervention) purposes. This crucial point is not
widely understood by many practitioners or lay audiences.
There are also other difficulties in using brain
studies as indicative of a condition (dyslexia) as, this work
involves correlational data. It has been shown, for example, that
intervention results in increased activation and, therefore, fMRI
merely shows what is happening at any given time rather than an
underlying problem that causes reading difficulty.
3.8 Dyslexia (ie biologically-based reading
difficulty) can be accurately diagnosed on the basis of a clinical
interview and educational assessment.
Comment: There is a disingenuous sleight
of hand operating here. The link between identifying biological
explanations and conceptualisations and offering a differential
diagnosis on the basis of presenting symptoms and various cognitive
and academic test scores is not at all straight forward.
3.9. Dyslexia is typically defined as unexpected
poor performance in reading. Thus, it is based upon a comparison
with the individual's functioning in other areas. Dyslexics often
demonstrate a "sea of strengths" (Shaywitz) in other
areas and this can be a signpost for diagnostic purposes.
Comment: Does this adequately accord with
a biological explanation of reading difficulty? Is it not possible
that someone with dyslexia would be just as likely to be weak,
as to be strong, in other areas? In addition, are there some areas
of strength that are necessary/sufficient for a meaningful diagnosis?
This seems unclear at present.
Can you be dyslexic if you are from an unstimulating
environment, have a low IQ and demonstrate few, if any, strengths?
Surely, the answer must be in the affirmative but, if so, does
this not demolish the use of terms such as "unexpected performance"
for diagnostic purposes?
3.10 It is possible to diagnose dyslexia
on the basis of the presence/absence of a number of symptoms.
Comment: We are in horoscope country here.
The lists are very longlook hard and you'll invariably
find some confirming features; multiple permutations are possible.
There is no essential distinguishing element (eg the presence
of working memory difficulties) and two identified dyslexics can
have almost wholly different sets of symptoms (other than the
reading difficulty itself).
3.11 Differential diagnosis is important
because it will lead to appropriate forms of intervention.
Comment: In my opinion, this is a key
issue in respect of the Select Committee's inquiry. It is recognised,
even by dyslexia pressure groups, that the forms of intervention
typically recommended for dyslexics are equally valid for any
child encountering reading difficulties. Thus, a diagnosis of
dyslexia (irrespective of its questionable criteria) adds nothing
in respect of guidance for intervention.
What is important is that there are not faulty
attributions made about the child's intelligence or motivation.
However, it is still possible that the dyslexic child is cognitively
weak and that they may be unmotivatedhardly surprising,
given the struggle to cope in school that they will typically
encounter on a daily basis.
3.12 It is clinically and educationally
useful to differentiate dyslexics from other poor readers.
Comment: Is it possible to identify significant
numbers of poor readers (excluding those with obvious physical/sensory/mental
difficulties) who would not be classified as dyslexic? How would
they present? What would be the key discriminating features? How
would they be treated differently as a result of the diagnosis?
Clearly, there are many poor readers who do not get this label.
Is this differentiation more helpful than calling
all poor readers dyslexic until such time that science provides
a more valid means of differentiation? In my opinion, prolonging
a dyslexic/non-dyslexic distinction within the wider pool of poor
readers is arbitrary, does not inform differential intervention,
and is potentially harmful to those many poor readers who, for
many various reasons, may not be labelled as "dyslexic".