Narrative discourse in anomic aphasia

摘要

Anomic aphasia is a disturbance affecting lexical retrieval. Nonetheless, persons with this disorder may also experience difficulties in the construction of coherent narratives. Whether this symptom is a sign of a macrolinguistic difficulty per se or reflects the lexical disorder is still an open debate. In order to analyze the effect of the lexical impairment on macrolinguistic processing, we compared the narrative skills of a group of ten participants with chronic anomic aphasia with those of ten healthy control individuals matched for age and educational level. The anomic participants produced narratives with lowered speech rate, reduced mean length of utterance, fewer grammatically well-formed sentences, more semantic paraphasias. The macrolinguistic analysis showed that they also produced more errors of cohesion and global coherence and fewer lexical information units. Interestingly, their levels of thematic selection were normal. A bivariate correlational analysis showed a strong correlation between the production of errors of cohesion and production of complete sentences, and between production of errors of global coherence and lexical information units. These correlations showed that aspects related to lexical retrieval may affect macrolinguistic processing during the construction of a narrative. Indeed, it is suggested that lexical deficits lead to two main consequences: First, patients with anomia frequently interrupt the utterances they are producing and this reduces the levels of sentence completeness and the overall degree of cohesion across the utterances; Second, they use strategies to cope with the lexical impairment and produce a quantity of lexical fillers and repetitions that, clustered in utterances, reduce the levels of global coherence.