Book review. Current directions in dyslexia research. van den Bos, K.P., Siegel, L.D., Bakker, D.J. and Share, D.L. (Eds). Lisse: Swets & Zeitlinger, 1994
✍ Scribed by Bozena Wszeborowska-Lipinska; John Everatt
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 75 KB
- Volume
- 4
- Category
- Article
- ISSN
- 1076-9242
No coin nor oath required. For personal study only.
✦ Synopsis
Developments in Diagnosis, Treatment and Research. Both conferences addressed dyslexia and the development of literacy from a varied perspective, providing a meeting point of different approaches and orientations. As the title suggests, the book's target audience is the dyslexia researcher. The contents are divided into several sections, discussing, in turn, definitions, biological foundations, psycholinguistic aspects and remediation of dyslexia.
One theme running throughout is the questioning of current, widespread beliefs about dyslexia. Chapters by Stanovich and by Flecher et al. attack the IQ/discrepancy method of defining dyslexia. The scarcity of clear-cut differences between discrepant and non-discrepant poor readers in reading patterns, heritability and brain anomalies is presented as arguments for the abandonment of the discrepancy definition and the term dyslexia itself. One potential problem with these views is that they fail to consider the appropriateness of IQ tests in the assessment of cognitive potential among dyslexic individuals. A third chapter, by Siegel and Toth, does consider intelligence tests as a measure of potential intellectual capacity. What a pity, though, that the authors did not discuss those studies which suggest that some IQ subtests (such as Digit Span or Coding from the WISC) can be significantly affected by dyslexia.
Further chapters question the view that the core deficit in dyslexia is phonological. Whereas Been concentrates on a visual basis for some dyslexia characteristics (omissions and intrusions during reading), Rispens et al. present evidence for a dichotomy of causes leading to two subtypes of dyslexia, a viewpoint supported by data presented in subsequent chapters by Licht and by Kappers. Licht's findings suggest that the cortical brain activity of dyslexic individuals categorized as L-or P-types (after Bakker) differs in later stages of stimulus processing. Kappers presents evidence for the beneficial effects (even after 12 months) of neuropsychological treatment based on Bakker's viewpoint. Such findings lend biological and interventional support to the dichotomy viewpoint. Share, however, suggests that some inconsistencies in the phonological processing literature can be explained by a single domain-general temporal processing dysfunction. This single core deficit may explain the dyslexic's visual or crossmodality symptoms, poor short-term memory or problems with tasks demanding sequencing. The importance of both visual and phonological systems is also discussed by van Bon et al., who consider an interaction between the visual system and short-term memory. They argue that this may explain the paradox of spelling, which is considered as requiring phonemic awareness, appearing to be a simpler skill to perform than phonemic segmentation. Further research is necessary to specify the functions of these systems and indicate how they can be used in a strategic way to aid task performance.
Despite the inconsistencies outlined in several chapters, a great deal of evidence still supports the phonological core deficit hypothesis and suggests a crucial role for language in reading acquisition and reading problems. This is highlighted by chapters reporting research with non-English-speaking participants. The chapter by Leong discusses how the role of metalinguistic awareness (explicit knowledge of language skills) in reading acquisition varies across languages (such as English, Japanese and Chinese) according to the mapping of lexical or sublexical units and phonology. Van den Bos and Spelberg's chapter on real-word versus pseudoword reading of Dutch subjects indicates the possibility that reading profiles may be substantially different from those found in English-based literature. Further work on cross-language/orthography comparisons may be highly informative.
Although remedial techniques and therapeutic methods abound, there is a clear lack of research on their efficiency, and as Fletcher et al.'s chapter indicates, deriving conclusions from this research is made difficult by the use of incompatible definitions of dyslexia and different measures of reading disability/reading improvement.