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Behavioural Neurology
Volume 16, Issue 2-3, Pages 119-144

Multiple Levels of Letter Representation in Written Spelling: Evidence From a Single Case of Dysgraphia with Multiple Deficits

Marie-Pierre de Partz,1,2 Aliette Lochy,1,3,4 and Agnesa Pillon1,3

1Université Catholique de Louvain, Belgium
2Centre de Revalidation Neuropsychologique des Cliniques Universitaires Saint-Luc, Bruxelles, Belgium
3Fonds National de la Recherche Scientifique, Belgium
4F.C. Donders Centre for Cognitive Neuroimaging, Nijmegen, the Netherlands

Received 15 December 2005; Accepted 15 December 2005

Copyright © 2005 Hindawi Publishing Corporation and the authors. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In this paper, we report a detailed analysis of the impaired performance of a dysgraphic individual, AD, who produced similar rates of letter-level errors in written spelling, oral spelling, and typing. We found that the distribution of various letter error types displayed a distinct pattern in written spelling on the one hand and in oral spelling and typing on the other. In particular, noncontextual letter substitution errors (i.e., errors in which the erroneous letter that replaces the target letter does not occur elsewhere within the word) were virtually absent in oral spelling and typing and mainly found in written spelling. In contrast, letter deletion errors and multiple-letter errors were typically found in oral spelling and very exceptional in written spelling. Only contextual letter substitution errors (i.e., errors in which the erroneous letter that replaces the target letter is identical to a letter occurring earlier or later in the word) were found in similar proportions in the three tasks. We argue that these contrasting patterns of letter error distribution result from damage to two distinct levels of letter representation and processing within the spelling system, namely, the amodal graphemic representation held in the graphemic buffer and the letter form representation computed by subsequent writing-specific processes. Then, we examined the relationship between error and target in the letter substitution errors produced in written and oral spelling and found evidence that distinct types of letter representation are processed at each of the hypothetized levels of damage: symbolic letter representation at the graphemic level and representation of the component graphic strokes at the letter form processing level.