Grammatical class and imageability in aphasic word production: their effects are independent

Abstract

This paper addresses the recent claim that grammatical class differences found among aphasic patients may reflect semantic factors such as ease of imageability rather than lexical/syntactic class. Nouns and verbs equated for rated imageability, frequency and length were elicited as completions for spoken sentences. Five aphasic patients with significantly better production of nouns than verbs in picture naming continued to show a significant grammatical class effect in the completion task. Two patients with significant imageability effects in oral reading continued to show imageability effects in sentence completion, but only one of these patients showed any difficulty producing verbs. Inspection of the individual patient data indicated that either grammatical class, or imageability, or both variables may affect patient performance, but that their effects are independent of one another.