Research 
The IWAL-Institute is founded in 1983 as a part of the Department of Psychology of the University of Amsterdam. The main goal was to integrate scientific research and clinical practice in the area of dyslexia within one institution. Although the IWAL has become an independent expert centre for dyslexia nowadays, the goals have remained unchanged. The IWAL Research department focusses on scientific research in the area of dyslexia, in collaboration with both the department of Developmental Psychology of the University of Amsterdam and the Theo Schaap Dyslexia Foundation.
A central focus of the Research department is to make an impact on the development of effective treatment for dyslexia. This focus is expressed in several projects. Three representative projects are:
The evaluation of the effectiveness of the LEXY-treatment for dyslexia,
The development of new treatment components based on implicit, associative learning principles, and
The development of an intervention program for the reading comprehension difficulties of dyslexic students.
In addition, our research is concerned with test development and with uncovering cognitive mechanisms in dyslexia.
Project 1: Evaluation of the LEXY treatment
LEXY presents dyslexic participants with a learning system clarifying the basic (linguistic) elements and operations by which one’s writing system encodes the characteristics of the spoken language system. The treatment is computer-based and focuses on learning to recognise and use the phonological and morphological structure of Dutch words.
The starting point of the treatment is the phonetic structure, i.e. the set of phones, the categories of phones, and the standard orthographic representations. The syllabic structure of words is the focal point of the treatment. By taking the ‘spoken’ syllable as unit of processing, the attention of the dyslexic is drawn to a perceivable structure in contrast to a phoneme, which is an abstract entity. At the same time, in the Dutch writing system is the last phonic element of a syllable essential to the dissociation between a spoken word form and its orthographic representation. The correspondence between a phonic element and its standard graphical representation can be dissociated, depending on the phonological category to which the terminal phonic element of a syllable belongs. In LEXY this is incorporated in its inferential algorithmic kernel, having the following structure:
IF p /# E Pi then O(p) → g E G.
When the terminal phonic element p of a syllable belongs to the ith category of phonic elements Pi then the result of an operator O on p will be mapped onto a graphic element g that need not be the standard mapping. All essential terms in the algorithm have an explicit and exhaustive description in the program: the set of phones, the categories of phones, the mapping operations and the orthographic elements. This description is the central procedural structure of the program and has a full graphical representation on the computer screen; all elements of the description are also represented on a special keyboard (Schaap, 1997).
The effectiveness of the treatment is examined in a series of studies, aiming to evaluate both the external and the internal validity of the treatment. Among other things, goals of this research are to evaluate the presence of clinically significant effects, the extent of normalization of the reading and spelling skills, transfer-effects, long-term effects (4-year follow-up), the influence of individual characteristics, a process-oriented evaluation, and the dynamics of development of reading rate and reading accuracy during treatment.
The results of this project are reported in several publications.
Project 2: Implicit associative learning
It is assumed that a combined approach in which explicit learning is followed by implicit learning could be a refinement of existing intervention methods for dyslexia. Methods in which phonological elements are explicitly related to orthographic representations, such as the LEXY methods in the Dutch language, are proven to be effective in normalizing spelling skills and reading accuracy. Reading rate, however, has appeared to be less susceptible for intervention.
Based on existing data it can be concluded that the use of implicit intervention techniques in which excessive repetition is being applied, are promising as a mechanism to accelerate reading speed. In this research project it is aimed to refine the LEXY-treatment by the implementation of a complementary module with a purely implicit foundation. It is possible that the effectiveness of a complementary implicit module is dependent on the transparency of the orthography. Therefore, the effectiveness of this complementary implicit module in the LEXY method will be evaluated in both the Dutch and the Greek language system. In contrast to the Dutch orthography, which is considered semi-transparent, the Greek language has a transparent orthography.
Research to the development of grapheme-phoneme associations can also be worthwhile for diagnostics and prognostics. In this research project, it is aimed to develop a task that measures the learnability of grapheme-phoneme associations. The quality of this process-oriented task as a predictor for the effectiveness of the treatment will be examined.
Project 3: Intervention method for acquiring knowledge from informative texts
This intervention method is developed in order to attack the problems with the acquisition of knowledge from informative texts that dyslexic students can encounter in secondary education. Acquiring knowledge from informative texts is a necessary skill for studying learning material. An important assumption of the intervention is that the structure of informative texts can be considered as a construction in which a core concept has a central position and in which a number of concepts of a ‘lower order’are related to this core concept. (Doblaev, 1984; Kintsch & Rawson, 2005). The concepts of lower order make up the predicate of the core concept and can be elucidated themselves as well. In this way, the core concept and the other concepts together with their relations form a hierarchical structure. The interrelations between the different concepts are often not explicitly formulated in the text. Consequently, for a good understanding of the text the reader needs to discover these relations and needs to formulate relevant questions about the content of the text (Best, Rowe, Ozuru, & McNamara, 2005; Doblaev, 1984; Duke & Pearson, 2002).
By considering the structure of a text as a construction consisting of a core concept with specific relations with other important concepts, the essence of a text can be presented in the format of a visualized scheme. This is a useful strategy for pupils with dyslexia because they don’t have to read again, as would be the case with a written summary. Moreover, this approach focuses on the activation of ‘higher order’ processes (e.g. making inferences, monitoring) in contrast to the ‘lower order’ processes (e.g. decoding) in which dyslexics are disabled (cf. Cain & Oakhill, 2003; Ransby & Swanson, 2003).
Project 4: Cognitive mechanisms in dyslexia
Recently, a research project into the underlying factors of Rapid Automatized Naming (RAN) is started. It is known that RAN is associated with phonological processing capacities. Besides the phonological capacities, it is expected that general processing speed contributes to RAN. It is also hypothesised that certain inhibition processes contribute to RAN. A main research goal is to clarify the contribution of these (latent) factors to the RAN of children with dyslexia.
In addition, the relation of RAN and its latent factors with the reading skills of children with dyslexia before, during and after treatment will be examined. Reading skills will be examined with standard reading tests and with a computerised reading test. In this computerised reading test, one word a time is briefly presented (e.g. for 100 msec.) on the computer screen and the child has to say aloud which word was presented (response is without time constrains). It is expected that this test will provide a better indication of the strength of phoneme-grapheme associations than standard reading tests and that general processing speed and inhibition factors will be less associated with this test.
See this poster (a pdf file) for preliminary results of this research project.