This chapter will:
- discuss the purpose of a definition for dyslexia;
- provide pointers to indicate the current breadth of research in the area of dyslexia, which will be followed up in Chapter 2;
- examine the factors that influence the development of a working definition of dyslexia;
- look at the implications of DSM-5 for the use of the term âdyslexiaâ;
- highlight the impact of different perspectives and agendas in developing an operational definition for dyslexia;
- provide a focus on the area of positive dyslexia, looking at what they can do, not what they canât do.
As indicated in the last point above, it is important to focus on the positive aspects of dyslexia. One of the earliest pioneers in this area was Tom West, whose landmark book In the Mindâs Eye (1997) provided a launch pad for a new wave of research into the positive aspects of dyslexia. Perhaps one of the more refreshing statements regarding the potential attributes of people with dyslexia is made by West himself when he says: âit is becoming increasingly clear [that much of the success attributed to people with dyslexia1] is because of the dyslexia not in spite of itâ (West, 2014, p.78). West goes on to say that for years now we âhave too often focused on fixing the problemsâand have totally ignored the development of talentsâ (p.87).
Dyslexia is often seen as a hidden disability and the estimates from a range of sources suggest that 10â15% of the population have dyslexia and around 4â5% severely.
It is important to be clear when defining dyslexia; and a working definition must take the positive and creative aspects into account. Too often definitions can be general, vague and essentially serve little purpose. They can also be misinterpreted and misused. Definitions need to be contextualised so they are relevant to the teaching and learning context. This chapter will provide clarification on the use of definitions and highlight the need to consider a working definition for dyslexia.
Defining Dyslexia
The questions one needs to ask areâdo we really need to define dyslexia and can we really encapsulate the features and the feelings that accompany dyslexia in a single statement? These points can be considered when one asks people with dyslexia questions such as âwhat is dyslexia?â and âwhat does it mean to you?â As part of the research for this book I asked some children and adults those questions! There was a considerable range of responses. Some of the responses are shown below.
The following comment came from a teacher who is dyslexic.
Reading through these statements one is struck by the emotional feelings attached to themâand that is the problem with a definition of dyslexia: it provides a definitive and descriptive response to what for many can be an area of emotional stress and personal conflict. Yet for education and research purposes a definition is necessary: it is necessary to assist in developing identification and diagnostic criteria and to inform intervention. Definitions can help to provide a label. For many parents a label is necessary as it can help to kickstart the support process. For adults with dyslexia it can help them develop self-knowledge and eventually coping strategies. For teachers it can provide explanations as to why the child may not be responding to the intervention provided. A definition therefore can be an important catalyst in this process. This is why it is important to emphasise the positive aspects of dyslexia. A good source of information is the Dyslexia Advantage website (http://community.dyslexicadvantage.org).
This website highlights why it is important to understand the advantages of dyslexia and helps children and adults gain personal insights into their own learning traits, thereby providing the means for them to become independent, more insightful and more successful learners.
The problem, however, lies in the lack of a universally accepted definition of dyslexia. The recent revision of the Diagnostic Statistical Manual (DSM-5) (American Psychological Association, 2013) is unlikely to help the cause much as âspecific learning disorderâ is now the generic term to be used for reading, writing and mathematical difficulties. There are certainly sub-categories, but the authors of the DSM see the generic term as a positive aspect and believe that it is less restrictive and less limiting than previously. DSM-5 indicates that the diagnosis requires persistent difficulties in reading, writing, arithmetic or mathematical reasoning skills during the formal years of schooling. Symptoms may include inaccurate or slow and effortful reading, poor written expression that lacks clarity, difficulties remembering number facts or inaccurate mathematical reasoning.
A very crucial comment is made in the factsheet that accompanies DSM-5 when it indicates that the DSM-5 Neurodevelopmental Work Group concluded that the many definitions of dyslexia and dyscalculia meant those terms would not be useful as disorder names or in the diagnostic criteria.
It is true there are many different definitions of dyslexia, but there are many dimensions to dyslexiaâdyslexia is not represented by a single entity (or caused by a single gene). Dyslexia is multifaceted and that can explain why a single, universally accepted definition has not yet been achieved. It can be argued, however, there is some agreement on the constellation of factors that can contribute to dyslexia, but controversy surrounds the respective weighting of these factors. For example, the range of factors that can be associated with dyslexia includes the following:
- Structural and functional brain-related factors (Galaburda and Rosen, 2001; Hynd et al., 1995).
- Genetic factors affecting the developmental migration of magnocells in utero and influencing their subsequent function (Stein, 2008).
- Genetic correlations (Gilger, 2008).
- Procedural timing of sequences in task accomplishment (Fawcett and Nicolson, 2008).
- Processing speed (Wolf and Bowers, 2000).
- Inter-hemisphere transfer (Breznitz, 2008).
- Difficulty in automatising skills (Fawcett and Nicolson, 1992).
- Working memory difficulties (Jeffries and Everatt, 2004).
- Phonological deficit (Snowling, 2000).
- Language featuresâorthographic transparency (Wimmer, 1993; Share, 2008; Everatt and Elbeheri, 2008).
- Comorbidity between learning disabilities (Bishop and Snowling, 2004; Visser, 2003).
- Literacy achievement levels and the role of IQ in diagnosis (Siegel and Lipka, 2008; Joshi and Aaron, 2008; Wagner, 2008).
- Positive skills (West, 2014; Nicolson et al., 2012; Nicolson, 2014).
These points above illustrate the diversity found among the dyslexic population and are some of the factors that can influence our understanding of dyslexia. Each can have an impact on how dyslexia is perceived and how assessment and intervention are portrayed.
