PHONOLOGICAL ERRORS IN APHASIC NAMING - COMPREHENSION, MONITORING ANDLEXICALITY

This paper investigates the production of phonological errors in aphas ic naming, examining the relationship between these errors and deficit s in comprehension. The predictions of Deli and O'Seaghdha's (1991) co mputational model of speech production were tested by lesioning. The s et of lesioned models demonstrated a strong correlation between propor tion of phonologically related errors in naming and comprehension accu racy. In contrast, no correlation between proportion of phonological e rrors in naming and comprehension accuracy was found for a group of fi fteen aphasics. This paper also examines monitoring behaviours, such a s the presence of self-corrections and interrupted responses, again fi nding no relationship with auditory comprehension. There was also no e vidence for a lexical bias in the phonological errors for these aphasi c subjects. Phonologically related errors were argued to be words only by chance; this was supported by the fact that they occurred more fre quently on short words than long words, and that the proportion of rea l word errors was not significantly different to that observed in a ps eudocorpus of errors. We conclude that a production-based monitor woul d be compatible with these results but that any comprehension-based mo nitor is not reliably employed by some or all of the aphasic subjects examined here. Additionally, these data are incompatible with models o f language processing where speech input and output share the same pro cessing components.