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CCD Statement on Dyslexia and Reading Impairment

ARC Centre of Excellence in Cognition and its Disorders (CCD) - Reading Program
Macquarie University Department of Cognitive Science

Recently there has been debate around the term "dyslexia" and whether or not it is a useful word or concept. Though much of the debate is about how the word "dyslexia" affects things such as treatment decisions, a key part of the argument for eliminating the term is related to the way it is used and understood by the general public. Some researchers and clinicians feel that the term is used much too broadly, and should be eliminated and replaced by something clearer such as "reading disability" or "reading impairment."

We don't plan to settle that debate, but whether we use "dyslexia" or "reading impairment", the question of what that means is critical. To reduce miscommunication between us as researchers and others discussing reading problems, here is what we mean (and don't mean) when we discuss or publish articles about dyslexia and reading impairments:

Reading impairment is not a single problem: Though it may not feel like it to many of us, reading is a very complex task that involves many sub-skills and processes. It requires identifying and ordering letters, mapping letter patterns to sounds, and accessing knowledge stored in memory (among other things). This means that the process can fail in a variety of ways, so we will almost never say "dyslexia" or "reading impairment" without first discussing what kind of impairment we mean. Does the reader have trouble reading new words they have never seen before? Do they mistake broad for board more often than others their age? Do they read have to rhyme with save? Do they have trouble understanding what they have read? These are different problems that don't necessarily go together (and there are others).

No single treatment will work for all reading impairments: Since reading involves many different processes, any particular struggling reader may have difficulty in one or more of them. The particular difficulty they have determines the treatment they need. Based on current evidence, we believe that effective treatment of a struggling reader requires first identifying the specific reading problems the reader has, and then designing a reading-based program to develop the skills that have fallen behind. This means that one-size-fits-all treatments will not be effective for many readers with dyslexia.

Dyslexia and reading impairment are about problems with reading: That may seem obvious, but sometimes problems in other areas become so strongly associated with reading impairments that they start to be mistaken for dyslexia. For example, sometimes people with reading difficulties also have problems with working memory. This has led people to say things like "David forgets his homework a lot because he's dyslexic", which is not correct. If it were, then everyone who has dyslexia should also have memory problems, but this is not at all the case. Reading is a complicated task and problems can come up in a lot of different ways. A person with a problem in working memory does not have dyslexia unless they also have a problem with reading. A person with a reading problem may have no problems with working memory, but they still have a reading impairment. This is also true of motor skills, executive functioning, and a variety of other non-reading skills. In the extreme, one website claims Leonardo da Vinci had dyslexia not because of any evidence that he had trouble reading, but because he could write backwards and reversed (as in a mirror image). This is clearly using the term far too broadly.

Reading and spelling are related, but not the same: Some definitions of dyslexia include spelling problems. We do not. Spelling and reading are different skills even if they are both based on written language. There are some processes involved in both spelling and reading, so some people will have problems in both skills. But there are also processes that are specific to each task. As with working memory, this means that some people with spelling impairments do not have reading impairments and vice versa. To avoid grouping different problems together, we prefer to use the distinct terms dysgraphia or spelling impairment for problems in spelling, and dyslexia or reading impairment for reading problems.

Here are a few other things that are important to keep in mind when talking about dyslexia:

Reading skill and intelligence are not the same thing. Most children with low intelligence scores learn to read perfectly well, and many children who struggle to learn to read have high intelligence scores. Having a reading impairment doesn't mean you are either stupid or smart. It means you are a person who has trouble reading.

Research has found that genetics sometimes plays a role in reading difficulties. Sometimes the phrase "genetic cause" is mistaken for "there's nothing anyone can do." This isn't true for reading difficulties. No matter the cause of the dyslexia, there are treatments that can help.

Some children who are struggling to learn to read are struggling because of classroom teaching methods. Effective teaching methods for reading should always include systematic teaching of phonics, particularly in the early years.

Coloured lenses, coloured paper, or doing gymnastics are not effective treatments for any form of dyslexia. There are many more "snake oil" treatments out there, and many of them have been adopted by school boards and education administrators with no reliable evidence to support them. Currently, the evidence favours treatments that are based on developing reading skills that target the specific reading problem.

Signatories

  • Serje Robidoux, PhD, Department of Cognitive Science, ARC CCD
  • Nic Badcock, PhD, Department of Cognitive Science, ARC CCD
  • Anne Castles, PhD, Department of Cognitive Science, ARC CCD
  • Max Coltheart, PhD, Department of Cognitive Science, ARC CCD
  • Veronika Coltheart, PhD, Department of Cognitive Science, ARC CCD
  • Saskia Kohnen, PhD, Department of Cognitive Science, ARC CCD, Macquarie Cognition Clinic for Reading
  • Robin Litt, PhD, Department of Cognitive Science, ARC CCD
  • Eva Marinus, PhD, Department of Cognitive Science, ARC CCD
  • Genevieve McArthur, PhD, Department of Cognitive Science, ARC CCD, Macquarie Cognition Clinic for Reading
  • Lyndsey Nickels, PhD, Department of Cognitive Science, ARC CCD
  • Teresa Schubert, PhD, Department of Cognitive Science, ARC CCD
  • Hua-Chen Wang, PhD, Department of Cognitive Science, ARC CCD

List of References

Subtyping of reading problems

Castles, A., Bates, T., & Coltheart, M. (2006). John Marshall and the developmental dyslexias. Aphasiology, 20(9), 871-892.

Jones, K., Castles, A., & Kohnen, S. (2011). Subtypes of developmental reading disorders: Recent developments and directions for treatment.

Friedmann, N., & Coltheart, M. (in press). Types of developmental dyslexia. In A. Bar On, & D. Ravid (Eds.), Handbook of communication disorders: Theoretical, empirical, and applied linguistics perspectives. Berlin, Boston: De Gruyter Mouton.

Individualised treatment

Friedmann, N., & Coltheart, M. (in press). Types of developmental dyslexia. In A. Bar On, & D. Ravid (Eds.), Handbook of communication disorders: Theoretical, empirical, and applied linguistics perspectives. Berlin, Boston: De Gruyter Mouton.

Coltheart, M., & Kohnen, S. (2012). Acquired and developmental disorders of reading and spelling. The Handbook of the Neuropsychology of Language, Volume 1&2, 892-920.

Dissociation between reading and spelling

Moll, K. & Landerl, K. (2009) Double Dissociation Between Reading and Spelling Deficits, Scientific Studies of Reading, 13(5), 359-382.

Fayol, M., Zorman, M. & Lété, B. (2009). Associations and dissociations in reading and spelling French: Unexpectedly poor and good spellers. British Journal of Educational Psychology, 6, 63-75.

Dyslexia and intelligence

Siegel, L. S. (1989). IQ is irrelevant to the definition of learning disabilities. Journal of Learning Disabilities, 22(8), 469-478.

The importance of phonics in teaching

Ehri, L. C., Nunes, S. R., Stahl, S. A., & Willows, D. M. (2001). Systematic phonics instruction helps students learn to read: Evidence from the National Reading Panel’s meta-analysis.

 

Further Information

Contact Details

Telephone: +61 2 9850 4127
Email : ccd@mq.edu.au
Web : www.ccd.edu.au

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