Effect of Mandarin Verb Network Strengthening Treatment (VNeST) in Mandarin-English bilinguals with aphasia: A single-case experimental design

This study aimed to improve verb retrieval ability in Mandarin-English bilinguals with aphasia by adapting the Verb Network Strengthening Treatment (VNeST) into Mandarin Chinese. Two Mandarin-English bilingual patients with chronic post-stroke aphasia participated in this study via online conferencing system following a multiple-baseline design. Both of them completed a 10-week of Mandarin VNeST treatment, and were probed on verb retrieval ability in a sentence context in both languages. Response accuracy was analysed to investigate the treatment acquisition, within-language generalization, and cross-language generalization effects. Standardized language assessments in both languages were administered pre- and post-treatment to further examine generalization to other linguistic tasks. Error analysis was conducted to investigate the evolution of within- and cross-language errors. Both patients improved after training in Mandarin VNeST, and showed different patterns of within-language and cross-language generalizations. They also improved in a variety of standardized language tasks. Error analysis showed a decline in semantic errors over the course of treatment in both patients, with cross-linguistic errors showing a decrease during Mandarin probes and an increase during English probes in one of the patients. This study contributes to our current understanding of theories of bilingual verb processing, and provides treatment guidance in Mandarin-English bilinguals with aphasia.