The categorical distinction of vowel and consonant representations: evidence from dysgraphia.

Subject GSI presents with a graphemic buffer deficit following a massive left fronto-parietal lesion. His errors involved essentially only consonants (98.2%). However, he always spelled correctly the first consonant in a string, and produced steadily increasing numbers of errors on the following consonants, while always spelling all the vowels in the target correctly. The pattern of performance observed in this subject provides strong evidence for the separate (categorical) representation of consonants and vowels, and suggests that working memory interacts with independent consonant and vowel representations in spelling.