The relationship between working memory and metaphor comprehension in patients with right hemisphere damage

Abstract

Objectives: Metaphor comprehension is an aspect of pragmatics. Since working memory is recognized as a skill needed for the understanding of metaphors, it is necessary to study the association between working memory and metaphor comprehension in patients with right hemisphere damage (RHD). Methods: Twelve patients with RHD (without aphasia) and twelve normal adults participated in this study. They were subjected to a metaphor comprehension task, which included a familiar conventional metaphor and a novel metaphor. Working memory was assessed using a numerical span task and a word span task. Results: The results indicated that the patients with RHD performed more poorly in the metaphor comprehension task compared to the normal adult group. However, both groups exhibited better comprehension of the conventional metaphor than the novel metaphor. Furthermore, the patients with RHD performed poorly in all working memory tasks compared to the normal adult group. The normal adult group showed significant and static correlation in conventional metaphor comprehension and word span tasks. In contrast, the RHD group showed significant correlations between all of the working memory tasks and each of the two metaphor types. Conclusion: The results of this study indicate that patients with RHD display defects in working memory as well as in metaphor comprehension compared to normal adults. This implies that limited working memory affects an individual's understanding of the meaning of words and sentences within a metaphor.