Although the article was about dyspraxia, it could equally well have been about developmental dyslexia, dyscalculia or dysphasia. These neurological labels are applied to children whose development is uneven, with selective deficits in the domains of literacy, mathematical skills, and oral language development respectively. They are often described as neurodevelopmental disorders, a category which can be extended to encompass attention deficit hyperactivity disorder (ADHD), and autistic disorder. Unlike conditions such as Down syndrome or Fragile X syndrome, these are all behaviourally defined conditions that can seldom be pinned down to a single cause. They are subject to frequent challenges as to their validity. ADHD, for instance, is sometimes described as a medical label for naughty children , and dyslexia as a middle-class excuse for a child’s stupidity. Autism is a particularly interesting case, where the challenges are most commonly made by individuals with autism themselves, who argue they are different rather than disordered.
So, what does the science say? Are these valid disorders? I shall argue that these medical-sounding labels are in many respects misleading, but they nevertheless have served a purpose because they get developmental difficulties taken seriously. I’ll then discuss alternatives to medical labels and end with suggestions for a way forward.
Parents often have a sense of relief at being told their child is dyslexic, as they feel it provides an explanation for the reading difficulties. Most people assume that dyslexia is a clearcut syndrome with a known medical cause, and that affected individuals can be clearly differentiated from other poor readers whose problems are due to poor teaching or low intelligence.
In fact, that is not the case. Dyslexia, and the other conditions listed above, are all diagnosed on the basis of behavioural rather than neurological criteria. A typical definition of developmental dyslexia specifies that there is a mismatch between reading ability and other aspects of cognitive development, which can’t be explained by any physical cause (e.g. bad eyesight) or poor teaching. It follows that if you have a diagnosis of dyslexia, this is not an explanation for poor reading; rather it is a way of stating in summary form that your reading difficulties have no obvious explanation.
But medicine progresses by first recognising clusters of symptoms and then identifying underlying causes for individuals with common patterns of deficits. So even if we don’t yet understand what the causes are, could there could be value in singling out individuals who meet criteria for dyslexia, and distinguishing them from other poor readers? To date, this approach has not been very effective. Forty years ago, an epidemiological study was conducted on the Isle of Wight: children were screened on an extensive battery of psychological and neurological measures. The researchers were particularly interested in whether poor readers who had a large discrepancy between IQ and reading ability had a distinctive clinical profile. Overall, there was no support for dyslexia as a distinct syndrome, and in 1976, Bill Yule concluded: “The era of applying the label 'dyslexic' is rapidly drawing to a close. The label has served its function in drawing attention to children who have great difficulty in mastering the arts of reading, writing and spelling, but its continued use invokes emotions which often prevent rational discussion and scientific investigation".(p 166). Subsequent research has focused on specifying what it is about reading that is so difficult for children who struggle with literacy, and it’s been shown that for most of them, a stumbling block is in the process of breaking words into sounds, so-called phonological awareness. However, poor phonological awareness is seen in poor readers of low IQ as well as in those with a mismatch between IQ and reading skill.
2. Medical labels don’t identify conditions with distinct causes
What about if we look at underlying causes? It's an exciting period for research as new methods make it possible to study the neurological and genetic bases of these conditions. Many researchers in this field anticipated that once we could look at brain structure using magnetic resonance imaging, we would be able to identify ‘neural signatures’ for the different neurodevelopmental disorders. Despite frequent over-hyped reports of findings of ‘a brain scan to diagnose autism’ and so on, the reality is complicated.
I'm not attacking researchers who look for brain correlates of these conditions: we know far more now than we did 20 years ago about how typical and atypical brains develop, and basic neuroscience may help us understand the underlying processes involved, which in turn could lead to better diagnosis and intervention. But before concluding that a brain scan can be a feasible diagnostic test, we need studies that go beyond showing that an impaired group differs from an unimpaired group. In a recent review of pediatric neuroimaging and neurodevelopmental disorders, Giedd and Rapoport concluded: “The high variability and substantial overlap of most measures for most groups being compared has profound implications for the diagnostic utility of psychiatric neuroimaging” (p. 731) (my italics)
Similar arguments apply in the domain of genetics. If you are interested in the details, I have a blog explaining in more detail, but in brief, there are very few instances where a single genetic mutation can explain dyslexia, ADHD, autism and the rest. Genes play a role, and often an important one, in determining who is at risk for disorder, but it seems increasingly likely that the risk is determined by many genes acting together, each of which has a small effect in nudging the risk up or down. Furthermore, the effect of a given gene will depend on environmental factors, and the same gene may be implicated in more than one disorder. What this means is that research showing genetic influences on neurodevelopmental disorders does not translate into nice simple diagnostic genetic tests.
3. No clear boundaries between individuals with different diagnostic labels
To most people, medical labels imply distinct disorders with clear boundaries, but in practice, many individuals have multiple difficulties. Maxine Frances Roper’s blogpost on dyspraxia illustrates this well: dyspraxia affects motor co-ordination, yet she described major problems with maths, which would indicate dyscalculia. Some of her commentators described cases where a diagnosis of dyspraxia was accompanied by a diagnosis of Asperger syndrome, a subtype of autistic disorder. In a textbook chapter on neurodevelopmental disorders, Michael Rutter and I argued that pure disorders, where just one domain of functioning is affected, are the exception rather than the rule. This is problematic for a diagnostic system that has distinct categories, because people will end up with multiple diagnoses. Even worse, the diagnosis may depend on which professional they see. I know of cases where the same child has been diagnosed as having dyslexia, dyspraxia, ADHD, and “autistic spectrum disorder” (a milder form of autism), depending on whether their child is seen by a psychologist, an occupational therapist, a paediatrician or a child psychiatrist.
4. No clearcut distinction between normality and abnormality
There has been much debate as to whether the causes of severe difficulties are different from causes of normal variation. The jury is still out, but we can say that if there are qualitative differences between children with these neurodevelopmental disorders and typically developing children, we have yet to find them. Twenty years ago, many of us expected that we might find single genes that caused SLI or autism, for instance, but although this sometimes occurs, it is quite exceptional. As noted above, we are usually instead dealing with complex causation from a mixture of multiple genetic and environmental causes. Robert Plomin and colleagues have argued, on the basis of such evidence, that ‘the abnormal is normal’ and that there are no disorders.
Many people worry that if we say that a label like dyslexia is invalid, then we are denying that their child has real difficulties. This was brought home to me vividly when I was an editor of Journal of Child Psychology and Psychiatry. Keith Stanovich wrote a short piece for the journal putting forward arguments to the effect that there were no qualitative differences between poor readers of average or below average IQ, and therefore the construct of ‘dyslexia’ was invalid. This attracted a barrage of criticism from people who wrote in to complain that dyslexia was real, they worked with dyslexic children, and it was disgraceful for anyone to suggest that these children’s difficulties were fictional. Of course, that was not what Stanovich had said. Indeed, he was very explicit: “Whether or not there is such a thing as 'dyslexia', there most certainly are children who read markedly below their peers on appropriately comprehensive and standardized tests. In this most prosaic sense, poor readers obviously exist.” (p. 580). He was questioning whether we should distinguish dyslexic children from other poor readers, but not denying that there are children for whom reading is a major struggle. Exactly the same cycle of events followed a Channel 4 TV documentary, the Dyslexia Myth, which raised similar questions about the validity of singling out one subset of poor readers, the dyslexics, and giving them extra help and attention, when other poor readers, with very similar problems but lower IQs, were ignored. A huge amount of debate was generated, some of which featured in the Psychologist. Here again, those who had tried to make this case were attacked vehemently by people who thought they were denying the reality of children’s reading difficulties.
Among those taking part in such debates are affected adults, many of whom will say ”People said I was stupid, but in reality I had undiagnosed dyslexia”. This is illuminating, as it stresses how the label has a big effect on people’s self-esteem. It seems that a label such as dyslexia is not viewed by most people as just a redescription of a person’s problems. It is seen as making them more real, emphasises that affected people are not unintelligent, and leads the condition to be taken more seriously than if we just say they have reading difficulties.
So what would the consequences be if we rejected medical labels? Here, it is fascinating to chart what has happened for different conditions, because different solutions have been adopted and we can compare and contrast the impact this has had. Let’s start with dyslexia. On the basis of the Isle of Wight study, Bill Yule and colleagues argued that we should abandon the term ‘developmental dyslexia’ and use instead the less loaded and more descriptive term ‘specific reading retardation’. Because of the negative connotations of ‘retardation’ their proposal did not take off, but the term ‘specific reading disability’ was adopted in some quarters. But, actually, neither term has really caught on. When I did a bibliometric survey of studies on neurodevelopmental disorders, I tried to include all possible diagnostic labels as search terms. I've just looked the frequency with which different terms were used to describe studies on developmental reading difficulties. Dyslexia won by a long margin, with over 97% of articles using this term.
Quite the opposite happened, though, with ‘developmental dysphasia’, which was used in the 1960s to refer to difficulties in producing and understanding spoken language in a child of otherwise normal ability. This term was already going out of fashion in the UK and the USA in the 1970s, when I was doing my doctoral studies, and in my thesis I used ‘specific developmental language disorder’. Subsequently, ‘specific language impairment’ (SLI) became popular in the US research literature, but there is current concern that it implies that language is the only area of difficulty, when children often have additional problems. Among practitioners, there is even less agreement, largely because of an explicit rejection of a ‘medical model’ by the profession of speech and language therapy (speech-language pathology in the US and Australia). So instead of diagnostic labels practitioners use a variety of descriptive terminology, including ‘language difficulties’, ‘communication problems’, and, most recently in the UK ‘speech, language and communication needs’ (SLCN). [If you've never heard of any of these and want to see how they affect children's lives, see http://www.afasicengland.org.uk].
There do seem to be important negative consequences, however. As Gina Conti-Ramsden has argued , specific language impairment (or whatever else you want to call it) is a Cinderella subject. The amount of research funding directed to it is well below what you’d expect, given its frequency and severity, and it would seem that most members of the public have no idea what it is. Furthermore, if you say a child has ‘developmental dysphasia’, that sounds more serious and real than if you say they have ‘specific language impairment’. And to say they have language ‘difficulties’ or ‘needs’ implies to many people that those difficulties are fairly trivial. Interestingly, there also seems to be an implicit assumption that, if you don’t have a medical label, then biological factors are unimportant, and you are dealing with problems with purely social origins, such as poor parenting or teaching.
An article by Alan Kamhi had a novel take on this issue. He argued that a good label had to have the properties of a meme. The concept of a meme was introduced by Richard Dawkins in the Selfish Gene, and subsequently developed by Susan Blackmore in her book The Meme Machine. A meme is an element of culture that is transmitted from person to person, and a successful meme has to be easy to understand, remember and communicate to others. Importantly, it does not necessarily have to be accurate or useful. Kamhi asked “Why is it more desirable to have dyslexia than to have a reading disability? Why does no one other than speech-language pathologists and related professionals seem to know what a language disorder is? Why is Asperger’s syndrome, a relatively new disorder, already familiar to many people?” (p. 105). Kamhi’s answer is that terms with ‘language’ in them are problematic because everyone thinks they know what language is, but their interpretations differ from those of the professionals. I think there is some truth in this, but there is more to it than that. In general, I’d argue, the medical-sounding terms are more successful memes than the descriptive terms because they convey a spurious sense of explanation, with foreign and medical-sounding labels lending some gravity to the situation.
So here’s a proposal that attempts to steer a course through this morass. We should use the term ‘neurodevelopmental disability’ as a generic term, and then add a descriptor to indicate the areas of major difficulty. Let me explain why each part of the term is useful. “Neurodevelopmental” indicates that the child’s difficulties have a constitutional basis. This is not the same as saying they can’t be changed, but it does move us away from the idea that these are some kind of social constructs with no biological basis. The evidence for a biological contributory causes is considerable for those conditions where there have been significant neurological and genetic investigations: dyslexia, SLI, autism and ADHD.
I suggest ‘disability’ rather than ‘disorder’ in the hope this may be more acceptable to those who dislike dividing humanity into the disordered and normal. Disability has a specific meaning in the World Health Organization classification, which focuses on the functional consequences of an impairment for everyday life. People who are the focus of our interest are having difficulties functioning at home, work or school, and so ‘disability’ seems a reasonable term to use.
It follows from what I’ve said above, that the boundary between disability and no disability is bound to be fuzzy: most problems fall on a scale of severity, and where you put the cutoff is arbitrary. But in this regard, neurodevelopmental disability is no different from many medical conditions. For instance, if we take a condition such as high blood pressure: there are some people whose blood pressure is so high that it is causing them major symptoms, and everyone would agree they have a disease. But other people may have elevated blood pressure and doctors will be concerned that this is putting health at risk, but where you actually draw the line and decide that treatment is needed is a difficult judgement, and may depend on presence of other risk factors. It’s common to define conditions such as dyslexia or SLI in terms of statistical cutoffs: the child is identified as having the condition if a score on a reading or language test is in the bottom 16% for their age. This is essentially arbitrary, but it is at least an objective and measurable criterion. However, test scores are just one component of diagnosis: a key factor is whether or not the individual is having difficulty in coping at home, work or school.
‘Neurodevelopmental disability’ alone could be used to indicate that the person has real difficulties that merit attention and support, but it lumps together a wide range of difficulties. That is no bad thing, however, given that many individuals have problems in several domains. The term would actively discourage the compartmentalised view of these different conditions, which leads to an unsatisfactory situation where, for instance, researchers in the US have difficulty doing research on the relationship between reading and language disabilities because these are seen as falling under the remit of different funding streams (NICHD and NIDCD respectively), or where a researcher who is studying language difficulties in autism will have much greater chance of obtaining funding (from NIMH) than one who is studying language difficulties in non-autistic children (which are far more common).
Having defined our generic category, we need to add descriptors that specify weaknesses and strengths. Identification of areas of weakness is crucial both for ensuring access to appropriate services, and to make it possible to do research on individuals with common characteristics. Table 1 shows how traditional medical categories would map on to this system, with a downward arrow denoting a problem area, and = denoting no impairment. But this is just to illustrate how the system corresponds to what we already have: my radical proposal is that we could do away with the labels in the top row.
|Table 1: Traditional categories (top row) vs new system|
In addition, a key feature of my proposed approach would be that assessment should also aim to discover any areas that parents or children themselves identify as areas of strength (up arrows), as fostering these can be as important as attempting to remediate areas of difficulty. If we take Maxine Frances Roper as an example, she evidently has good language and intelligence, so her profile would indicate this, together with weaknesses in maths and motor skills.
When we consider people’s strengths, these may not be in cognitive or academic skills. Consider, for example, Temple Grandin. She is a woman with autism who has become a highly respected consultant in animal husbandry because of her unusual ability to put herself in the mind of the animals she works with. Obviously, not every person will have an amazing talent, but most will have some activities that they enjoy and can succeed in. We should try and find out what these are, and ensure they are fostered.
For a start, it is complex and has resource implications. Few practitioners or researchers would have the time to do a comprehensive assessment of all the areas of functioning shown in Table 1. Nevertheless, many people would complain that this list is not long enough! What about memory, speech, spelling, executive function, or visuospatial skills, which are currently not represented but are studied by those interested in specific learning disabilities? The potential list of strengths is even more open-ended, and could encompass areas such as sports, music, craft and cookery activities, drama, ability to work with animals, mechanical aptitude and so on. I’d suggest, though, that the approach would be tractable if we think about this as a two-stage procedure. Initial screening would rely on parent and/or teacher and/or self report to identify areas of concern. Suitable well-validated screening instruments are already available in the domains of language, attention, and social impairment, and this approach could be extended. Areas identified as specific weaknesses could then be the focus of more detailed assessment by a relevant professional.
The main reason I doubt my system would work is that too many people are attached to the existing labels. I’m sure many will feel that terms such as autism, ADHD, and dyslexia have served us well and there’s no need to abandon them. Professional groups may indeed be threatened by the idea of removing barriers between different developmental disorders. And could we lose more than we gain by ditching terminology that has served us well, as least for some disorders?
Please add your comments
I certainly don’t have all the answers, but I am hoping that by raising this issue, I’ll stimulate some debate. Various academics in the US and UK have been talking about the particularly dire situation of terminology surrounding speech and language disorders, but the issues are broader than this, and we need to hear the voices of those affected by different kinds of neurodevelopmental disabilities, as well as practitioners and researchers.
With thanks to Courtenay Frazier Norbury and Gina Conti-Ramsden for comments on a draft of this post.
PS. 27th December 2010
A couple of relevant links:
More on failure of speech-language pathologists to agree on terminology for developmental language disorders.
Kamhi, A. G. (2007). Thoughts and reflections on developmental language disorders. In A. G. Kamhi, J. J. Masterson & K. Apel (Eds.), Clinical Decision Making in Developmental Language Disorders: Brookes.
A recent Ofsted report, concluding that many children with 'special educational needs' are just poorly taught.
PPS. 19th June 2011
Problems with the term 'speech, language and communication needs':
Lindsay, G. (2011). The collection and analysis of data on children with speech, language and communication needs: The challenge to education and health services. Child Language Teaching & Therapy, 27(2), 135-150.