‘Little words’—not really: function and content words in normal and aphasic speech

Abstract

Production and comprehension of content and function words was compared in aphasic patients who showed an apparent dissociation between these categories of vocabulary in spontaneous speech. These comprised four patients who had suffered CVA (three non-fluent and one fluent) and one fluent patient with semantic dementia (SD) or progressive aphasia. Where discrepancies in performance between, for example nouns and function words, were shown in reading, these effects disappeared when imageability was controlled. This suggests that the abstractness of function words might be responsible for poor performance in some aphasic patients, in the same way that imageability has been shown to be associated with poor verb production and comprehension in aphasia. A triads method was used to assess the semantic (and/or syntactic) information which could be accessed from the written word. An association was demonstrated between control subjects’ RT data and accuracy in patients. It was apparent that there was no simple dissociation between content and function words for any of these patients, and accuracy for all but the SD patient correlated with imageability. This patient performed at chance on all manipulations in both content and function words except that of gender, suggesting the preservation of this aspect of semantic knowledge.