Noun and Verb Impairment in Single-Word Naming and Discourse Production in Mandarin-English Bilingual Adults with Aphasia

ABSTRACT

Background

Previous studies on bilingualism and aphasia have identified a similar pattern of verb-noun dissociation in single-word naming (i.e., lower accuracy for verbs than nouns) in both languages. However, whether a similar pattern of verb and noun dissociation emerges in discourse production remains unknown, particularly in typologically dissimilar languages.

Aims

This study investigated patterns of verb and noun impairment in both single-word naming and discourse production, and whether naming was associated with lexical retrieval in discourse production in Mandarin-English bilingual adults with aphasia (BWA).

Methods

Twelve Mandarin-English bilinguals with chronic aphasia completed standardized assessments on object and action naming, and three discourse tasks from the AphasiaBank (i.e., sequential pictures, single-picture, storytelling) in both L1 (Mandarin) and L2 (English). Item-level accuracy of object and action naming was fit into a generalized mixed-effects model to estimate single-word naming ability as a function of grammatical category. The proportion of verb and noun production and the number of verbs and nouns per utterance were fit into multivariate linear regression models to assess lexical retrieval in discourse. Finally, another linear regression was performed to examine the association between naming and lexical retrieval in discourse production.

Results

The naming accuracy for verbs was lower than for nouns in both L1 and L2. Mandarin-English BWA also demonstrated less production of verbs than nouns in discourse. However, depending on the type of the task, the effect of word category was greater in L2 than in L1. This cross-linguistic difference of the verb-noun dissociation was diminished in individuals with lower aphasia severity. Our results further showed a direct relationship between naming and lexical retrieval in discourse, irrespective of the language.

Conclusions

Our findings suggest an overall similar pattern of verb and noun dissociation across different linguistic contexts. However, depending on the cognitive-linguistic demands of the task, the verb-noun dissociation may emerge in L1 and L2 to varying degrees in individuals with different levels of aphasia severity. This study facilitates better understanding of verb and noun retrieval in Mandarin-English BWA.

KEYWORDS:

• verb and noun retrieval
• naming
• discourse
• bilingual aphasia

Acknowledgements

The authors would like to thank the individuals who participated in this study. We also thank the members of the Aphasia Research Laboratory for their support throughout the development and execution of this study. Special thanks to Hongli Zheng, who transcribed the discourse data for fidelity check. Also, many thanks to Michael Scimeca and Jee Eun Sung for their constructive feedback on this manuscript.

Disclosure statement

No potential conflict of interest was reported by the first author. The second author is a scientific consultant for The Learning Corporation (FKA Constant Therapy) but there is no scientific overlap with the work in this project.

Additional information

Funding

This work was supported by the Boston University Sargent Student Research Grant [number 9250001170]; Authors were funded by the NIH/NIDCD under Grant [number 1U01DC014922].