Vowels in the buffer: a case study of acquired dysgraphia with selective vowel substitutions

We report the case of a patient who recovered from a clinical picture of fluent aphasia to selective dysgraphia. The features of the writing disorder were compatible with a graphemic output buffer dysfunction (errors in all spelling tasks and for all type of material, affected by word length and consisting mostly of graphemic deviations), with the exception of the lack of transposition errors and position preference. Further, the spelling disorder was selective for vowels, replicating the original observation by Cubelli (1991). A similar, although milder, error pattern was also observed in reading tasks, in particular for nonwords, suggesting that the locus of dysfunction involves a processing stage shared by reading and writing. These findings support the notion that the consonant-vowel status is a property of graphemic representations, and is compatible with that a common buffer is involved in spelling and reading. We discuss the implications of selective vowel disorders for current models of the spelling system.