Syntactic and semantic organization in word form retrieval?

Many studies have reported that naming disorders may affect selectively certain semantic categories (animals vs. vegetables or artifacts, see Caramazza and Shelton, 1998, for a review) or syntactic categories (open vs. closed class items, Friederici and Schoenle, 1980, nouns vs. verbs, Baxter and Warrington, 1985; Caramazza and Hillis, 1991; Daniele et al., 1994; McCarthy and Warrington, 1985; Miceli et al., 1988) suggesting that the conceptual system and the output lexicon are organized along both syntactic and semantic dimensions. Most current models of speech production distinguish two components in the output lexicon: lexical selection and word form retrieval. Lexical selection consists in comparing the conceptual representation of the object to be named to the lexical entries, and selecting the best match. Conceivably, this level should be both sensitive to syntactic and semantic parameters. Word form retrieval involves recovering the phonological information associated to the selected entry which is then used to construct a phonological plan to be executed by the articulatory system. Prima facie, word form retrieval should not be influenced by syntactic, and even more, semantic variables. However, Cohen et al. (1997) reported the case of a patient impaired in word form retrieval, as evidenced by a predominance of phonological paraphasias in naming and reading tasks, which totally spared names for numbers. The authors speculated that the topographical segregation of numbers in the conceptual system propagates along the speech production pathway, even down to word form retrieval. In this paper, we report the case of another aphasic patient who shows a word form retrieval impairment in production which surprisingly spares certain syntactic and semantic categories.