In “Dyslexia, Dysgraphia, Procedural Learning and the Cerebellum,” Roderick Nicolson and Angela Fawcett present a fascinating and, to me, strong argument for unifying theoretical views of dyslexia and dysgraphia. To be sure, their analysis is preliminary and basic, but my first read left me feeling as if they’d hit lots of good points. They’ve emphasized impairment of automatic procedural learning in the cerebellum at the level of neural circuits, but in dysgraphia the problems are with motor circuits and in dyslexia they are in the language circuits. In developing their case, they integrate a broad range of neurological and psychological research.
In this review we focus on the developmental disorders of dyslexia (a disorder of reading) and dysgraphia (a disorder of writing), considering their commonalities and differences with a view to reflecting on the theoretical implications. Interest in dysgraphia was stimulated by the distinction between phonological and surface dyslexia (Castles and Coltheart, 1993), which claimed that orthographic problems (spelling) were separable from phonological reading problems. While this distinction has received mixed support ([Snowling et al., 1996] and [Stanovich et al., 1997]) it led to a fruitful analysis not only of the underlying causes of orthographic difficulties, but also to the widespread recognition of developmental difficulties in handwriting control ([Deuel, 1995], [Manis et al., 1996] and Sprenger-Charolles et al., 2000 L. Sprenger-Charolles, P. Cole, P. Lacert and W. Serniclaes, On subtypes of developmental dyslexia: Evidence from processing time and accuracy scores, Canadian Journal of Experimental Psychology-Revue Canadienne De Psychologie Experimentale 54 (2000), pp. 87–104. Abstract | Full Text via CrossRef[Sprenger-Charolles et al., 2000]). The result of this theoretical and empirical progress is that there are two usages of the term dysgraphia. One takes dysgraphia to refer to errors of writing that are analogous to errors in reading (e.g., surface, phonological or deep dysgraphia corresponding to surface, phonological and deep dyslexia), the other relating to difficulties in handwriting control. Furthermore, despite these attempts at differentiation, there remains some controversy in the literature as to whether motor difficulties in handwriting should be subsumed under the label dyslexia.
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Sigh–new content
Despite getting virtually no recommendations about future content (3 votes!), I’m starting to post some new content. The new content is, in my obviously biased view (else, why would I post it?), pretty important stuff. It’s about research, practice, knowledge, and all that sort of stuff as it connects to Learning Disabilities. In this page, I discuss big-idea concepts that recur in Learning Disabilities. These are the themes that one sees when one reads a diverse array of literature on the topic of LD.
I recommend it. What’s more, you won’t have to find this post each time you want to refer to the page; it will always be directly accessible under the “special content” link in the top navigation bar.