Gresham College Lectures

Dyslexia and Language - Disorder or Difference? - Maggie Snowling CBE

February 27, 2024 Gresham College
Gresham College Lectures
Dyslexia and Language - Disorder or Difference? - Maggie Snowling CBE
Show Notes Transcript

Difficulties with reading and writing have wide-ranging effects beyond academic achievement, including on career opportunities and personal well-being. However, the concept of dyslexia continues to be debated: is the term useful? How does it relate to spoken language?

This lecture describes what is known of the causes and consequences of reading difficulties and how they relate to other common conditions that affect learning. It will look at the importance of early intervention and how best to support children with dyslexia.

This lecture was recorded by Maggie Snowling CBE on 8th February 2024 at Barnard's Inn Hall, London

The transcript and downloadable versions of the lecture are available from the Gresham College website:

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I guess many of you in the audience will, uh, I guess all of you will know someone with dyslexia. Some of you may be dyslexia yourself. Um, everyone has their own personal experience of dyslexia, and this evening we're going to consider therefore whether dyslexia should be considered a difference or a disorder. So what is dyslexia? The Gresham College lecture that you're listening to right now is giving you knowledge and insight from one of the world's leading academic experts, making it takes a lot of time, but because we want to encourage a love of learning, we think it's well worth it. We never make you pay for lectures, although donations are needed, all we ask in return is this. Send a link to this lecture to someone you think would benefit. And if you haven't already, click the follow or subscribe button from wherever you are listening right now. Now, let's get back to the lecture. Well put simply, dyslexia is simply a difficulty in acquiring reading and spelling fluency. So this is a book, the title of which I know is dyslexia, but I can't read it. And here, a 16-year-old young man of above average ability is having great difficulty in writing how he would want to design his house more formally. Dyslexia is a neurodevelopmental disorder, which means that it has an early onset, and it is lifetime persistent. It's likely to be highly heritable. Dyslexia is important to society, not least because poor reading and spelling in primary school often leads to disengagement from school. Poor educational achievement in secondary school, and this is in turn, will lead to limited job opportunities, low levels of adult productivity and wellbeing. But dyslexia turns out to be controversial and was ever thus. And why should that be? Well, in my opinion, the reason that dyslexia is controversial is that there are no clear cut differences between people with dyslexia and people who have typical reading. Dyslexia is not like chickenpox where those spots are the hallmark of the problem, the illness rather, that it's more like blood pressure. So blood pressure is a dimension. It varies in the population from low to high. There's no clear cut difference between having high blood pressure and having normal blood pressure. But we do create a category, we call it hypertension, and we treat it. And if we didn't do that, there would be serious health consequences. So I think dyslexia can be thought of in similar terms. Reading is a dimension which varies from, um, poor and inaccurate to fast and fluent. But this shows the, um, normal distribution of reading skill in the population. And what this, um, indicates is that about 80 90% of the population can read relatively well. They, they have good proficient reading, but at the bottom of the distribution, there are people whose reading is really of concern. Where you put the cutoff though is arbitrary. It has to be decided by some external criterion. Now, population studies suggest that about 7% of the population has dyslexia. So you might say, well, dyslexia then is the bottom 7%. I've certainly heard it referred to as the bottom 5%. And in some, uh, local authorities, I know you have to be in about the bottom 2% to get any identification for dyslexia. So this seems to me why it is a controversial disorder. What then, can history tell us about it? As you may know, dyslexia was first identified or reported in this country in 1896 by a general practitioner, Pringle Morgan, who was referred a 14-year-old boy called Percy. He couldn't actually write his name, but his name was Percy. And he seemed very able in most domains, and he was good at sport. But in spite of a lot of teaching and a lot of extra help, he still, according to Pringle, Morgan couldn't write a single syllable, couldn't read a single syllable. So Pringle Morgan hypothesized that Percy had a congenital form of word blindness. And this idea was taken up at the beginning of the 20th century, primarily by medical specialists. And an influential figure at the time was James Selwood, um, a glaswegian eye surgeon who became particularly concerned that there were children who had this reading difficulty and it needed to be identified because if not, they would be neglected in the, uh, in the schools or flogged. Um, which, you know, thankfully doesn't happen anymore. Um, what Selwood said, though, I mean he was used to dealing with problems of vision, visual impairments, was that he said the problem wasn't in vision. It was actually a naming visual object. So congenital word blindness was really to do with the naming function, and that's was an important insight, which many, uh, years later has come again, uh, to the fore. In the 1920s, um, Samuel Ton, uh, pediatric neurologist, um, pioneered the study of dyslexia in the us. He's probably most well known for the fact that he established a clinic with his wife June, shown here at, on their wedding day. Um, and in this clinic, they, um, appointed two very talented educators, um, Anne Gillingham, who's an educational psychologist, and Bessie Stillman, a specialist teacher. And together they worked out methods for helping children with dyslexia. At the time, it wasn't called dyslexia, uh, ton referred to it as Stre Andia to, um, really define the fact that these children often showed reversals and problems with orientation in their reading and writing. But he also didn't think it was a reading problem. He produced this very important book, reading, writing, and Speech Problems in Children, in which he argued that, um, dyslexia or stria was some kind of problem with the language faculty. And I think that was a very important insight. He documented many cases in this book, and he also reported the fact that dyslexia seemed to run in families. Um, but furthermore, it wasn't that in a family everybody was dyslexic. What he found was that in a family, you might get one person who had a reading problem, another person had a spelling problem, another person had a speech problem. So he was aware of the familiar nature of dyslexia, but he equally was clear that, that its, its inheritance was somewhat, um, complicated. Now, in Britain, um, there had been a bit of a lull in, uh, dyslexia research, but in 1963, the word blind center was opened in London in Corrum Fields by no less than Princess Margaret. And this was an important center because it brought together professionals from a range of different disciplines, all of whom were interested in the, um, in the treatment of children who are struggling to learn to read. So brought together neurologists, um, psychologists, specialists, teachers, speech and language therapists. And really, they, they worked incredibly hard to develop assessment and teaching methods for dyslexia. An important output of the center was this definition of dyslexia, a disorder manifest by difficulty learning to read despite conventional instruction, adequate intelligence and sociocultural opportunity, which is dependent on fundamental cognitive disabilities, frequently of constitutional origin. Now, this definition is often been criticized because it's a, it's a definition by exclusion. It implies that to be dyslexic, you would've had to have had good education. And that's clearly not the case. Um, but I think it's interesting that although we now I think, understand that dyslexia is more diverse and implied by this definition, it is one that stood the test of time and really marked out the field for many, uh, years. And the word blind center also had a very important influence, um, which led to an expansion of, uh, dyslexia knowledge and the dyslexia community. Um, and it's very interesting 'cause these developments were, um, principally led by women. Um, and I'll say something about why I think that's interesting in a minute, but on the left of this slide is Sanya Nadu, who was the second director of the center. And she subsequently went on to be the head of a school for children with language disorder rather than dyslexia per se. She wrote a fantastic book, specific, specific dyslexia in 1972, which really, uh, taught us how to assess dyslexia. Um, at the top of the slide next to her is Helen Arkel, who founded a teaching center below her, Bev Hornsby, a speech and language therapist who, with Maisie Hold, established the dyslexia clinic at Barts Hospital. And then there's Margaret Newton, who established a research center at Aston University, which really developed the first proper assessment kit for dyslexia. And in the top right hand corner, a very important figure, Marian Welshman, who founded the British Dyslexia Association, which went on to have really a global influence on understanding of dyslexia. Now, the reason, uh, the, the, the involvement of these women had an unfortunate consequence because to quote, they were women of certain means, they all were able to focus in on dyslexia because essentially some of them were volunteers and they didn't need to work because they had rich husbands. Um, and, um, also many of them were fighting for their own kids. So dyslexia became dubbed a middle class syndrome, and this gave policy makers a perfect excuse to not actually div divert any resources to helping dyslexic children. Indeed. Um, when, um, Baroness Warnock was asked by the then secretary of, uh, state for education to chair a committee on, uh, special educational needs, she was expressive, forbidden to call anyone from the dyslexic community to give evidence. And she was even forbidden to use the term, which is really quite, um, extraordinary. Now, fortunately, uh, in the background, the, uh, science of reading was, um, flourishing and, uh, many experimental and cognitive psychologists were beginning to get very interested in the reading process itself. Now, regardless of, um, the language, um, reading is a process of decoding print into sound. And, um, in our alphabetic system, um, we have letters and we have, um, individual, uh, speech sounds. Um, what the, uh, early, um, pioneers of dyslexia research were thinking was that this system had to be really functioning well for reading to develop, um, fluently. And, um, most of the research was focusing on the possibility that the problem might be in, uh, deciphering the print, which wasn't surprising, giving earlier research on visual difficulties in dyslexia, or it might be in the fact you had to go from one domain, the visual domain to the verbal domain, a problem in sort of cross modal, um, transfer. Um, however, um, in 1979, this guy Frank Tino, wrote a landmark textbook in which he argued the problem, um, with, um, dyslexia. And, and was that, was that in reading? It wasn't to do with the visual aspects of the process, it was actually to do with the sound based or the speech based, um, aspect. And, uh, he, he argued then that dyslexia shouldn't be considered a perceptual deficits, and reading shouldn't really be being considered a perceptual process. It actually was a language process. And the problem in dyslexia was some kind of verbal, uh, deficit. And he gave us an example, the sort of letter reversals that you see, uh, very often in, in dyslexia, the, the confusion of letters like B and P or. And he, he showed convincingly in a series of experiments that these difficulties were actually not to do with, uh, the perception of these letters, but to do with confusion over the names. So again, picking up this earlier idea that the problem was in the naming of visual objects, not in the visual processing itself. Um, at around the same time, the, uh, Haskins laboratories in the US um, was, um, considering in depth the challenges that a child faces in learning to read. So in learning to read, as I've already said, the child has to set up some kind of system for decoding print into speech. And in our alphabetic system, uh, the, um, print is in, in graphemes or letters. And the, um, the speech part is at the level of the phon. That is the smaller speech sounds in a word that convey meaning differences. So in a word like cat, we have three phon, and the, and we, there's a phonemic difference between cat and back, just in one particular phone. If you're going to understand how this alphabetic system works, if you're going to abstract the alphabetic principle, you really have to be aware of the phonemic structure of words. And actually, that's something that doesn't come naturally to children. Children think about cats as being very animals with whiskers. They don't for a minute think that they are something with three speech sounds. And to acquire that, um, awareness of the phonological structure of words is quite a, quite a, um, a challenge, quite a step for the child, um, in the early, uh, school years. But it's fundamental to learning to read. And what, um, was being discovered in the 1970s was that the problem in dyslexia is with this phonemic system, the phonological representations, the way in which our brain represents speech sounds and this phonological deficit, um, in dyslexia, can also help explain some of the other issues that people do with dyslexia face, and just some of them here on, on the, on the slide. So, people with dyslexia often have difficulty with names. They forget people's names, they have trouble with proper names, and they have great difficulty if you ask them to name items very quickly. Psychologists use a task called rapid naming, where you have to simply name as quickly as possible a series of letters or digits or colors. They find this difficult, they're very, uh, slow at it. A classic feature of dyslexia is a poor phonological or verbal short term memory. So remembering short sequences of verbal items. And, uh, a a particularly rather specific aspect of, um, verbal memory is the ability to repeat words that you haven't heard before, A non word repetition deficit or a phonological memory problem. So a word like a nomad like magnificent, is that easy to pronounce? I, I've practiced it a lot, but for people with dyslexia, it's quite hard to repeat those kinds of words. And relatedly, there is a problem with verbal learning. Um, this, um, is, is particularly, uh, important in the school context because a lot of verbal learning has to go on very early on. Children have to learn letters. That's one of the first markers of a child likely to have dyslexic difficulty in learning letters. Um, they have to learn digits, they have to learn colors, days of the week, months of the year. So verbal learning difficulties, all of these difficulties can be traced to problems with, um, the, in the phonological system, um, of language. Now, um, by the 1980s, um, reading researchers had ama a large, um, amount of, uh, data about how we read essentially data about the relative difficulty of reading different kinds of words. So in English, we have a very inconsistent orthography. Some words are regular, but other words are very irregular, like glove or school. Um, the even is an irregular word. So we know, we knew from a lot of experiments that these kind of irregular words were harder to learn than, uh, regular words. And there was sufficient data available to begin to model the reading process, um, by, in a, in a simulation. And one of the earliest, and still I think the most influential co computational model of, uh, reading was that, um, reported or, or developed by Seidenberg and McClelland in 1989, the so-called triangle or Connectionist Model of Reading. And in this model, um, reading is envisaged as a kind of division of labor between this phonological pathway from orthography to phonology, and another pathway from orthography to the meaning of words, a semantic pathway. But in the model, the implementation was of this phonological pathway. And the way in which they did it was that they had distributed representations in the orthographic, um, system and, uh, in the phonological system. And the, um, the, the, the, the, the, the computer model was, um, given words to, um, decode. Um, and, um, there was also inbuilt and error correction mechanism because given the irregularities, that mapping doesn't always work very well. When the mapping worked well, the connections were strengthened. Um, and, uh, when it didn't work well, there was an error correction. And this went on until the, uh, the model that simulated human reading very well in indeed. And so it was a really remarkable achievement. And the next thing was in this simulation, would it be possible to simulate dyslexic reading behavior? And the way in which they tried to do that was by degrading the phonological representations in the model. And when they did that, the model started to produce the reading errors that we see in dyslexia. Started to have much more difficulty reading non words than words, and started to make errors that what might be described as kind of visually based visual looking errors. So this was an explicit, explicit proof, if you like, that dyslexia is a core phonological deficit. And 40 years after the start of research on dyslexia, Tino wrote a review again, uh, reflecting on his verbal deficit theory, um, showing that now this verbal deficit theory had been refined to, um, a phonological deficit theory, uh, an idea that dyslexia was due to problems in the phonological representations, the way in which the brain represents the speech sounds, um, of words. So, given this accumulated knowledge and that we know what seems to be causing at least the cognitive level dyslexia, why not kind of get it early? Well, of course it's quite hard to get it early because it's hard to see dyslexia before reading instruction. But one method that can be used to begin to understand the precursors of dyslexia is through a family risk study. So, um, we've known since Samuel Ton that dyslexia, um, uh, is, comes in families. Um, this is my family, by the way. This is my father, my brother, and my nephew who are all, uh, dyslexic. Um, I've escaped it. Um, my son hasn't. Um, so we know that there is, um, high heritability of dyslexia. And what that means is you can recruit children who are at family risk of dyslexia if you, if you know about their parental reading skills, and you can then follow them from early on before reading instruction through the early years of reading to a point where you then think you can assess and decide whether or not they're dyslexic. And there have now been, um, several of these studies, um, over, over the studies, um, together the, um, risk, if you're a dyslexic parent of your child having dyslexia is about 45%. So that's very high. It's much higher about four times the probability, um, in the, in the, in the non dyslexic parent population. So one, uh, study of children at family risk that we conducted, um, recruited children when they were three and a half, um, and, uh, followed them to eight. We actually followed some of them till nine as well. But at three and a half, um, we assessed, we conducted an assessment of their, I'm gonna call dyslexia risks, which was actually their language skills. And eight, we, um, assessed them to, um, identify those that, uh, reached criteria for dyslexia. And we compared the development of these children with two other groups. First of all, a group who in the preschool years had language difficulties because we knew that language difficulties were a risk factor for dyslexia. Dyslexia is part of the, uh, difficulty of the language faculty to quote ton, uh, but the, the preschool language difficulties children in this group would, were not at family risk, it was just because they had been referred to speech and language therapy when they were three years old. And we had a group of controls who had neither, um, any concerns about their development, nor any, uh, family members with dyslexia. And I'm gonna show you, um, three pieces of data from this study. First of all, um, the preschool language profiles of the children. Now, um, we've got here three panels. So we've got here children who are in the control, the typical group children at family risk and children, um, with preschool language difficulties. I'm using the acronym here, DLD, um, that's developmental language disorder. Um, although it wouldn't be diagnosed at this stage because some of these children often get better, it was the children with the language concerns. Now, on the, on the X axis in each panel is a measure of phonological processing. It's actually a measure of non-word repetition. And on the y axis is a measure of language understanding comprehension. And in each of the, um, panels, the this dot, the vertical dotted line is one standard deviation below average for the population to the left in phenology. And the horizontal line is one standard deviation below average in language. And we can look at the, um, the different groups here. So there's a lot of variability in the typical group. Most of the children are in this upper right quadrant. They're actually above, you know, they're, they're doing fine in language and phonology, which is what you would expect looking at children at family risk. Now, when we recruited them, we, we were measuring their language, not their phonology, but you can see a lot of them in the top right hand quadrant have, um, phonological difficulties, uh, sorry, it's your left <laugh>. Um, they have, um, phonological difficulties. One or two of them have some language problems. And if you look at the language, uh, concerns group, a lot of them on the left of this line have, um, phonological difficulties. They also have language difficulties by definition. Now, what does this mean about their reading outcomes? When these children are eight years of age, what proportion of them would fulfill criteria for dyslexia? So, um, in the typical group, it's 7%, which is spot on what population studies suggest it should be in children at family risk, 26% of them have dyslexia, so about a fourfold risk. And then, um, in terms of the language concerns, group, 66 of them have, uh, reading skills that suggest that they, um, are dyslexic. So this study takes us a bit further than, um, thinking about dyslexia as a phonological deficit. Um, it confirms that it is, and it also confirms that that's evident before reading instruction. But it also suggests there's an additional risk factor lurking here, which is, uh, a language problem. Now, we can also use, um, data from this study to look at how children in different outcome groups are doing in other skills are important for education. And one very important skill for education is, uh, reading comprehension. I mean, the aim of reading is really reading for meaning. And by the time you're in the middle to to late primary school, years, years, you're expected to be able to read for meaning in terms of outcomes. We have three groups. We have children who are dyslexic. We also have a group of children who've got now this developmental language disorder, but actually they can read, they can decode print well, so they're not dyslexic. And we've got children who are both dyslexic and have a language disorder. And what I've, what I've plotted here is their, um, comprehension deficit. So, so what we did is we asked them to read some passages, and then we asked them verbally some questions about the passage. And, um, this was a measure of their reading comprehension. And shown here is the gap between their reading comprehension and that of the control group. And what you can see is that for the dyslexic children, these are effect sizes. Um, they've got some problems with reading comprehension, but they're not that bad. They're broadly in the average range, but they are weak for their age. The children with language disorder, even though they can read those texts very well, can't understand them. And if you've got dyslexia and language disorder, you have very significant difficulty with reading comprehension. It's almost like these two things are additive. The dyslexia, which seems to be associated with phonological problems, the language disorder, if you add 'em together, you get a much bigger sort of deficit. So, um, this is another way of thinking about this. So this is a schematic representation of some data that we, um, collected, which, um, looks at the predictors of individual differences in reading, um, from age three, um, onwards, uh, to, um, six and eight. Um, so we measured language at age three, and we measure aspects of the alphabetic principle, fer awareness and letter sound knowledge at, um, age five, as well as rapid naming, which is another dyslexia feature. And then we measure reading at age six. And what we, what we know already is that individual differences in phoning awareness and letter sound knowledge. The alphabetic principle predict reading attainment. What this study showed us is that earlier on in development language actually predicts the alphabetic principle, and that has a, a direct effect on word reading, but it also has a direct effect later on in development, on reading comprehension. Now, within this model, then there are two risks for dyslexia. The first risk is the risk. I've been talking about the phonological deficit. The second risk is an earlier, uh, and persisting language, um, impairment. So, um, this idea fits well with the research evidence that language is the foundation of literacy. Um, and, um, we now know we need, we can be intervening much earlier, but where do these risks come from? Well, we know that dyslexia runs in families. So are these differences, uh, do they have a genetic origin? Now, the problem with family studies is that families don't just share their genes, they also share their environment. So there's a confound here. Um, twin studies can be very enlightening, especially if you compare monozygotic twins who are identical. They share a hundred percent of their genes with, um, dizygotic twins, twins, which are non-identical. They're just like a brother and sister, and on average share 50% of their genes. Now, if you have a dyslexic twin, what is the probability that your cotran will be dyslexic? That's what refer to as a concordance rate. And what on average is seen across studies is that the concordance rate for identical twins is 70% compared to about 40% for non-identical twins. So these kind of data, um, sort of, um, confirm that the causes of dyslexia, uh, have a genetic, uh, component. So the heritability of dyslexia was a starting point for molecular genetics. And, and, and the studies of the molecular genetics of dyslexia started in the 1970s. Essentially, these studies then try to find genetic differences between people with dyslexia and, and their relatives who are unaffected. The first studies were so-called linkage studies that looked for parts of the, um, chromosomes that, um, differed between affected and unaffected, uh, people. And these linkage studies identified, uh, gene markers on a number of different chromosomes. Um, and certainly there was replication of these findings on chromosomes 1, 2, 3, 6, 15, and 18. The next step then was to try to identify the actual genes that were involved. So there was a search then for candidate genes, again, with some success, but none of these genes account for very much variance in reading. Um, in fact, they account for tiny amounts of variants, so they are not, um, really giving us much of a clue as to the genetic basis of dyslexia. More recent, um, advances in gene technology allow, um, researchers to look across the whole genome, um, to identify gene Loki that are associated with dyslexia. And in this recent study, 42 Loki were associated with dyslexia. Again, each accounting for a very small amount of variance. But what you can do is you can count, you can count them up, you can combine them to give a kind of risk score for an individual that's a kind of index of their risk of becoming dyslexic. Um, and so, um, that's been quite, um, uh, an important advance. However, again, we are not gonna counting for huge amounts of variants, but also there are complex interactions between genes and also between genes and the environment. And we need to bear in mind always that genes act through the environment. And for a complex disorder like dyslexia, there's a, there's a combination of heredity and hereditary and, uh, environmental influences referred to as gene environment correlation. We see aspects of the gene environment correlation acting out in home literacy environments. So what's the literacy environment in the home like? And how does it relate to reading? Well, Shaw and Lathea, um, developed a model, uh, in, in 2002, in which they showed that, um, two aspects of the home environment predicted reading in, in children. One was the extent to which books are shared between parents and children, and the other is whether or not a child actually actively teaches words or letters or writing your name. The parent teaching bit produces, uh, improvements in emergent literacy, the shared book reading in language. The two things come together to produce individual differences in reading. And of course, parents vary in the extent to which they do these activities. This is referred to as active gene environment correlation, but they're also passive influences as well. If parents are very literate, their chil their par, their children see them reading, and that might encourage them to read evocative gene environment. A a child's genetic disposition might encourage them to take part in literary activities. And of course, beyond the home, there's lots of environmental influences. I can't have time to go into them, but in the school, the government policies, the culture, and indeed the language, and I've only talked about alphabetic systems, but obviously across the world we have lots of different writing systems. The bottom line is in all of these systems, phonological difficulties seem to be associated with dyslexia. So given all the different genes, given the diverse environments, it's perhaps not surprising that we see individual differences, individual experiences of dyslexia, this is my family again, but just, um, to say that they're not all the same. They were all dyslexic. My father was an engineer, had high visual-spatial skills. My brother had a DHD with dyslexia, and his son has a language difficulty with dyslexia. So what we are seeing here is that these genes that are associated with dyslexia are coding for overlapping disorders. And formally we refer to this as comorbidity. It's, I think what Aton was observing when he saw the different members of a family had slightly different sorts of, um, disorder, but all of the language faculty. So drawing together what we've learned about causes, it's becomes clear that we have to think in multifactorial terms. We have biological causes, we have cognitive causes, and we have environmental causes. And all of these causes impact how the many genes involved in learning to read come together to, um, develop either a typical reader or a reader with dyslexia. The more, um, risk factors I would hypothesize, the more likely you're going to have, um, dyslexia. The core of dyslexia is a phonological deficit, but often it co-occur with language difficulties or with attention problems. And we might then say, these are co co-occurring conditions, dyslexia and DLD dyslexia and A DHD, or we might think it's a dimension of neurodevelopmental disorder, but it's not a, it's not a council of despair because children also inherit strengths. And strengths can often lead to compensation. But the most important form of compensation, of course, is intervention. And for an intervention to be, to work well, ideally, it needs to be theoretically motivated and it needs to be evaluated and shown to be effective using a randomized control trial if it's become part of practice and policy. And in RCT, children are randomly allocated either to receive an intervention or business as usual. And at the end of the intervention, if the intervention children are doing better than the, um, business as usual, then we know the intervention is effective. And in England now, the, uh, education Endowment Foundation is, is funding a lot of promising, uh, interventions, uh, uh, RCTs on promising intervention to try to develop a stronger evidence base for education. We have actually pretty strong evidence, I would say, gold standard evidence that interventions that train phony awareness letter knowledge and linking these in the alphabetic principle and then practicing those skills work really well for helping children with dyslexia. This is, uh, just one of the, these interventions that was developed by my colleagues, um, and it can be delivered by trained teaching assistants. Essentially at the core of the program is this, what we call sound linkage learning letters, learning phone names, linking them together, often using writing. And then at the beginning and the end of each lesson, there's reading from books chosen initially, the beginning to be easy to build site vocabulary, and at the end at an instructional level so that they can practice and hone the decoding skills that they're learning. In this middle of what my colleague refers to as the reading intervention sandwich, the, um, evidence is strong and, and the approach has been, uh, included in a number of different guidance, um, reports for teachers. But we must remember that what I've been saying is that it's not just phonology, it's not just language. There's also a, a language foundation that underpins the development of the, um, alphabetic principle. So should we be intervening on language? Well, I would say with some children, we should be. And with this in mind, we develop the Nuffield Early Language Intervention program, otherwise known as Nelly, which is a 20 week program of language, um, delivered to children who enter school with poor language development. Um, and it's delivered again by trained teaching assistance. Nelly has two 10 week, uh, modules, um, and in each module there's a alternating each week between group and individual sessions. There are three themes, developing narrative skills, enriching vocabulary, and improving speaking and listening. And in the second 10 week, um, module, the children also have training in phoning awareness and letter knowledge. But remember, these are children in our schools. So in the background, in their mainstream, they're also getting quite a lot of phonics. There's no reading in this program at all, but there is encouragement of the alphabetic, uh, principle. We now have strong evidence from two research and three much larger scale randomized trials that this early language intervention works. It improves children's language, it has a beneficial effect on the foundations for reading, and it also actually improves their behavior. And it's particularly cost effective when it's used in combination with a screening tool that we developed for this trial in which teachers can use to identify the children in their class when they come to school, who are in need of language support. It has been said not by me, that, um, Nelly has the largest, strongest evidence base for a language intervention in the uk. And, uh, possibly, uh, internationally this might be why. Um, our government decided, um, to, um, fund Nelly as part of a, the COVID-19 catch up scheme in, uh, disadvantaged schools. And so Nelly has now been rolled out, um, across schools in English. It is still fully funded. And, um, we have evidence that even in the wilds of classrooms, it is as effective as it was when delivered in the small group, uh, settings, uh, which we were overseeing as part of the research trials. So is dyslexia a disorder or is it a difference? Well, um, over its history, campaigners have lobbied to keep the concept of dyslexia as a disorder alive, but it's not a clear cut diagnostic category. Um, and it can range from very mild to really quite severe. So it's a kind of dimensional disorder. Um, but the very important thing is that we mustn't adhere to a medical model, which says diagnosis is important. Before intervention comes. We know enough about learning to read and the risks of not learning to read, for us to be able to intervene without waiting for diagnosis. And of course, we must be mindful that language sets the stage four learning to read. It's still important to raise awareness of children's oral language difficulties. Everyone knows about dyslexia, but many fewer people know about developmental language disorder. It's a really important, uh, message that people need to know that some children going to school have got language difficulties and they need to be attended to if they're gonna learn to read and become literate and understand what they're reading. Uh, we also know that children who went to school with poor language are at high risk of, uh, dyslexia from many years of research. Um, and this is important not just for the current generation, but for the next. If a child has poor language in literacy as a result of some of these sorts of difficulties, they will have poor qualifications. This will lead them into low page employment if they have employment. This in turn, will reduce the, their home resources, and that will reduce the sorts of education and, and home literacy that they can provide for their own children. So if we don't intervene, we are into a downward spiral, which will lead to intergenerational, um, hardship. So just to, um, close, then I will leave the last words to my, um, uh, to the late Sir Jim Rose, who, uh, I'm a great admirer of, in his 2009 report, laid out an agenda, uh, for dyslexia. And he said, intervene, don't wait. Ensure a strong foundation in language, offer a graded approach to intervention and monitor response. Be aware of co-occurring features. They're not dyslexia, but they're co-occurring, and they can affect the impact of dyslexia and provide support, guidance, and appropriate arrangements to people with dyslexia. I think there's no time like now given our scientific understanding of dyslexia to begin to intervene. Thank you very much. Thank you very much, professor Milling. It's, um, really clear presentation of a very challenging problem for us. There been a few, um, interesting questions. The first one is, uh, how frequent are associations with other forms of neurodiversity? So if you have, um, dyslexia, how does it overlap with the other ones that we're maybe going to hear about in the rest of our series? So, um, the overlap with A DHD is probably the most, uh, prevalent. We're talking about 40 or 50%, but that's where we're looking at the diagnoses. And again, we have to remember, these are all dimensions. So if you think about how many people with dyslexia have attention difficulties, it's probably more than 40%. But to actually have the two diagnoses at the moment, um, the, the literature suggests 40%, um, 40 or 50% with language disorder. Um, I, I think with autism, classically autism, it's much lower once you start talking about autism spectrum disorder. There's probably some overlap, but I think we, that has not been researched as much as, um, those, those, um, disorders that affect learning. So I think we sometimes can, um, differentiate things that affect learning from those that affect other aspects of wellbeing. So a second group of questions is about, um, I guess you'd call it national educational policy. And, um, you may have read an article in the papers weekend about what was going on in Denmark about tr delaying, um, training to read until quite late, by my experience, five years or so, and encouraging play, particularly outside and physical play, uh, does, is how does that work? I mean, is that a mad thing to do? You don't seem dane seem just the same as us when you meet large groups of them. Yes, Yes. And and the other point about Danish is it's an irregular language like English is, it's, it's one of the most irregular. So, um, well this question is a very interesting one. I personally think we do teach reading too early and now it very much is part of the very early years curriculum. I think we could wait, but of course we don't have any evidence on this. What we need is some natural experiments where somehow some people are, are learning later. It's the same about intervention. We assume early intervention's important, but we've not tested it against later intervention. And certainly with the reading intervention that I've talked about, we know that works well with kids in secondary school as well. You just have to tweak the sort of reading material. Um, I'm gonna do something that I've spent 70 years trying to avoid and that's admitting that I'm dyslexic. Uh, one of the things that I have a problem with is left, right. Is this common? Um, <laugh>, uh, well, uh, in the days of the word blind center in the 1960s, some of those psychologists worked in child guidance clinics. So they were finding kids who had been referred for emotional and behavioral difficulties. And, but these psychologists were aware that it wasn't really, that wasn't the, that really was an underlying reading problem. So I, so I think that that's kind of you, you hid away. You might have acted out, you might have gone in all sorts of other directions, but I think that is not uncommon, um, consequence. And it's not uncommon for people with dyslexia to be late diagnosed and later to find where their real strengths lie. Maggie, there's, there's several questions which are almost the same here, really. What do you think the role is for speech and language therapists? I guess there may be one or two hiding in the audience, but what, what, what is the role for speech and language therapists in the management of dyslexia, if management's the right word? Yes. Well, I, I'm a great fan of speech and language therapists. We don't have enough of them. Um, I think because, um, dyslexia is, um, it typically thought of as part of the school system and part of teaching reading speech and language therapists are kind of, um, pushed out and not expected to contribute. But clearly many of children with dyslexia have underlying language problems that are neither being assessed nor treated. So I think one, they have a role to, um, in consultancy to ask for people's dyslexia, have they had more of a language assessment? And then secondly, with interventions like our language intervention, they could be, um, you know, encouraging schools to use them. Um, and, and indeed help I think working to kind of refine them because of course, although Nelly is, uh, has very effective, but some children still have significant needs and, and so that if they can find, um, data on kids who've had one language intervention, if you're still having trouble, then that's where they should be getting in with more individualized support. Now, I'm dyslexic. I didn't discover this until I went to university as a mature student. Mm-Hmm.<affirmative>. And I can't hear the relief when somebody said, you're not all my life. I've been told I was lazy and stupid. The point I wanted to make of, I know you are on about phonetics Now, nobody spotted that I had a hearing or site problem. And I've realized later on I read by sight. There's no question about it. When I was taught to read, they could have talked in Japanese for all the difference it made to me. So when they say, well, you really need to look at how children learn, that isn't a, this is the model for everything. Yeah, well, I think that what your experience is exactly what I would predict. So you're having difficulty with the phonics, if you like. And so you, you, you went, uh, you went visually. And uh, that's, um, that's a, that's what many higher ability people with dyslexia do. Um, often the downside is that you might not be very good at spelling. I'm not gonna ask you because if you've learned the words by her, it's holes when you come to spell the letter by letter sequence. Haven't got it. Okay. So here's another one. My, my husband, not my husband at the moment, my husband, my husband was dyslexic. Um, our children are not, but one is Dysgraphic and the other is Dyspraxic. Could could you tell us about the overlap? Yes. Well, this is precisely what Samuel Ton had, um, observed in, in his clinic, that in families, you, um, can have one person with dyslexia, one person with a language impairments in my family as well. Um, so I think this is 'cause when we, we, we now know a lot of different bits of the genes are involved. These, uh, gene, uh, Loki and, um, they, they code not just for one prob sort of difficulty. They also code for other ones. So I think that's what's going on here, that somehow some of the dyslexia genes more have gone to the father and some of the other neurodevelopmental conditions are being experienced by the other children. The only thing I'd say is that these, um, characterizations or, um, they, they can change with development. So it's not unusual, for instance, to get a dyslexia, uh, identified to have intervention and then as a teenager actually to find out you've got attentional problems. So, um, we don't really understand that, but there's definitely a sharing of these disorders and also some particularly sequential, uh, aspects of risk. Thank you very much. Very interesting. We've talked a lot about children. I'm 80 and I've got dyslexia. Have you got any tips for people my age?<laugh>, you look very young.<laugh> you should give me some tips on, on aging gracefully. Um, successful <laugh>, I was running a business at the time. I was 19. Very Successful. Yes. Okay. Then I think what you should be doing is running, um, mentoring for young people with dyslexia who want to go into business. Okay. No Tips for me. These colored screens, colored glasses mean nothing. Use voice recognition software and uh, get, get something to audio books, <laugh>. So being, uh, speaking a number of languages, like being bilingual as a child, does that affect, uh, 'cause you talk about phonics, does that affect, uh, dyslexia or would that kind of enhance your kind of lead language and speech?'cause my daughter's bilingual. Yes. Well, it's a complicated question and there's not much research on it, but I'll, I'll have a shot at it. Um, I don't think there's any evidence that being bilingual will cause dyslexia, but what you can find where you have very different languages, if you, if you're learning, say an alphabetic language like English and also Chinese, which is non alphabetic, you might actually have done fine in one of the languages. And then when you learn it, we go to the other language.'cause it's the challenge a little bit different. You become dyslexic in the other language. Overall being bilingual I think is a very good thing. And of course there's theories that it, it has other aspects in enhancing cognitive function. Is there any, um, evidence in medication helping dyslexia? There isn't any evidence for the efficacy of, of medical interventions, no. Yeah, That's nice. Straightforward. I was very interested, um, about the business of Chinese because they're a sort of videographic mm-hmm.<affirmative> type of symbols being very different from an an alpha numeric text of some kind. Is, is it, how hard is it for someone to learn or to be susceptible to the development of dyslexia? Because you were associating the, I can't remember the terms you used, but phone name and the graphing. Yeah, yeah, yeah. Well, um, strangely it used to be said back in the day that learning to read Chinese would be much easier.'cause you don't have to do that mapping between letters and pH names. But actually the problem with learning Chinese is that you have to learn a lot of different sound symbol associations. So the learning demands are actually huge for someone with a verbal learning difficulties. So I think you do have, um, dyslexia in Chinese we, and you do in Chinese because, um, there the, they don't have phoniums, but they do have, um, sounds at different of different tones. You find that people with dyslexia find it very difficult to differentiate those tones. So I think strangely across the languages of the world, there's more similarities and differences. Um, in terms of the vulnerability to reading problems. My cultural was Are there any cultural or societal factors that influence the perception and diagnosis of dyslexia? Yes. Well, I mean, cultural factors are really, um, very important. I mean, um, aside from the fact that, um, in some cultures, um, uh, you know, the, the, the education systems aren't very well developed. There are real cultural differences in the value of literacy. So we did, um, a randomized trial in a, in a small island, um, of, um, the coast of Chile and Robinson, cruso Island, in fact it's called. And um, we, um, we want, we were trialing a reading intervention there and we had quite a lot of difficulty because the families kept saying, we don't want to learn to read. We are a fishing community. It's not relevant to us. So yes, I think there are lots of cultural factors and, um, they haven't really been explored. Um, obviously there's the language of reading, which is also gonna be, uh, have a, have a, um, have an influence. And, and of course once you start thinking about this wider environmental influences, the the, the school's policies, I mean, if, if you have a school with good special educational need policy, your dyslexic child probably will fare quite well. But you could be in another school where the culture was, you know, we don't believe in it and dah, dah, dah, dah. And, and so really important point. Thank you, Uh, thank you very much for signing for your lecture. I'm just wondering if you know of any more recent or current studies looking at the genes, uh, the particular genes that are involved and if we've identified any more since the 2002 study. Um, so the, the one I put up, did I say 2002, it's 2022 <laugh>. Um, so that's one of the most recent ones. I know I'm not a geneticist, so I dunno the field, but there's also a very, uh, useful report, um, about genomics and educational attainment called the Hastings Report, which I've recently looked at, which I thought was very good.<laugh> Just, uh, just behind you at the back there. Thank you. Um, Maggie, thank you very much for a very full, uh, count. Um, can we go back to Mary Warnock's point about dyslexia being a middle class disease? Uh, when I trained as an educational psychologist in the 1960s at UCL, I was taught that dyslexia did not exist. Um, what has been the key factors in changing people's minds? Okay, but of course, Mary Warnock didn't think it was a middle class syndrome that the politicians did. Um, I think that the increase in the scientific evidence has been quite compelling. Um, I mean there's a, there's a lot of research on dyslexia, um, pointing to phonological problems and, and you know, realizing that they are real. Um, a lot of people have great hopes for genetics and, and neuroscience, but really we're a long way off using them at individual patterns of risk. But I, but I think, I think that's one thing. And then I, I think, um, they've also been just improvements in understanding the science of reading and how to teach reading. So, um, yeah, I mean, I'm not sure that politicians or policy makers still really use the term dyslexia. They, it's usually dyslexia, stroke specific learning difficulties. Um, but I think I would definitely say point to the scientific evidence. I'm take the privilege of the last question with respect to the, you, you showed a diagram there, which was, you know, if you've, if you're in a socially deprived cycle, things can get worse. Mm-Hmm, <affirmative>. So here we are with rising inequality and, um, sort of quite a lot of pressures on our educational services. What's the future for, for, uh, children with dyslexia in this country? Well, that's a difficult question, isn't it? Um, well first of all, I hope that regardless of political party, that we continue to have language intervention in schools to promote the development of children with dyslexia around children who also just have generally problems accessing the curriculum. I do hope we can fund teaching assistance because some schools can't afford them because teachers need help with children who have individual needs. But also I think with real lack of, um, appreciation of how helpful, uh, assistive technology can be. And I, my own view is if you have someone with dyslexia who you have been trying to teach for three or four years and is still having a huge struggle, we should one, be supporting their use of voice recognition software and other chat, GPT, dare I say, other ai, um, uh, uh, methods. Um, and, and also we need to be revamping the education system. We recognize their strengths and we can have, you know, more vocational training and not regarded as, you know, failure like some of the people here have experienced. Well, thank you very much. So absolutely magisterial presentation and really informative and thank you very, very much indeed, professor.