Writing disorders in Italian aphasic patients. A multiple single-case study of dysgraphia in a language with shallow orthography

We report results of a writing task given to 53 mildly to moderately aphasic Italian subjects. The task was designed to test the writing performance along the subword-level routine for the spelling of regular words and non-words, and along the lexical routine for the spelling of irregular words. The aim of the study was to identify the incidence of different dysgraphic subtypes in Italian, a language that is considered to have shallow orthography. Its spelling, however, is not completely free of ambiguity. A five-part writing task was used: (i) words with regular one-sound-to-one-grapheme conversion; (ii) words with regular syllabic conversion; (iii) words with ambiguous transcription; (iv) loan-words; and (v) non-words. For regular words, the effects of word length and word frequency, and of the variables determining the complexity of the acoustic-to-phonological conversion (continuant versus plosive phones; consonant-vowel sequence versus doubled consonants or consonant clusters) were also considered. Patients' performances were classified according to the presence of a dissociation between (i) regular words and non-words, (ii) regular words and words with unpredictable spellings, and (iii) one-to-one and syllabic conversions. The 53 aphasic patients span the whole spectrum of dysgraphic taxonomy. Thirty-nine patients, in particular, manifested a dissociated pattern of performance. Eighteen patients showed a prevalent surface dysgraphic pattern and seven a phonological one, while 11 patients showed a mixed pattern (i.e. a better performance for regular words than for ambiguous words or regular non-words). Three patients showed a specific deficit for regular syllabic conversion rules only. A high rate of 'mixed dysgraphia' suggests either a mutual interaction of the two impaired routines when regular words are written, or two separate functional lesions: one at the level of the auditory-to-phonological conversion procedure, the other at the level of the orthographic output lexicon.