Semantic Working Memory Predicts Relative Clause Sentence Comprehension: A Case Series Approach

Sentence comprehension involves simultaneous processes such as maintaining and integrating different types of verbal representations. As such, it has been argued that sentence comprehension relies on working memory (WM). Some findings suggest that semantic (word meaning) WM rather than phonological (speech sound) WM is critical for comprehension. This study took a case-series multiple regression approach to examine the relationship between sentence comprehension and WM for 56 individuals with aphasia. We examined the independent contribution of phonological and semantic WM in predicting comprehension for higher WM target sentences relative to matched lesser WM sentences, while also controlling for single word processing. We found that only semantic WM had a significant contribution to comprehension for three contrasts. However, for the fourth contrast of trials requiring syntactic processing with those requiring only lexical processing, both WM contributions were significant. The possible backup role of phonological WM for comprehension of role reversals is discussed