The effect of lexical deficits on narrative disturbances in fluent aphasia

Aims: This study aims at investigating micro- and macrolinguistic skills in persons with fluent aphasia. The label “fluent aphasia” applies to different aphasic syndromes characterized by fluent speech with difficulties in lexical retrieval and/or grammatical processing. We hypothesized that their lexical and syntactic (i.e., microlinguistic) difficulties would affect also their narrative (i.e., macrolinguistic) skills. Methods & Procedures: Growing evidence shows that traditional tests may not be sensitive enough to capture the patterns of the linguistic impairments observed in these persons. Therefore, we used a narrative task to elicit linguistic samples. Spontaneous speech was elicited through a picture description task. The narrative samples were analyzed with a multi-level approach that allows clinicians to quantify their productivity levels as well as their lexical, grammatical, and narrative skills. The spontaneous speech produced by a group of 20 persons with fluent aphasia was compared to that of a group of 20 healthy participants. All participants with aphasia were in the phase of neurological stability. The two groups were matched for age and level of formal education. Outcomes & Results: Results showed that the lexical impairment observed in the group of participants with fluent aphasia were related to difficulties also in the grammatical construction of the utterances and in the macrolinguistic organization of their speech samples. Conclusions: These findings support the possibility that in these patients microlinguistic difficulties might affect macrolinguistic processing. Furthermore, these results stress the importance of a multi-level approach to assess linguistic skills in patients with fluent aphasia, as it assesses both micro- and macrolinguistic dimensions in parallel. Therefore, it allows linguists, psychologists and clinicians to observe how the linguistic levels interact during natural language processing.