Effects of Verb Network Strengthening Treatment on retrieval of verbs and nouns in persons with aphasia

Objectives: The Verb Network Strengthening Treatment (VNeST) is a semantic treatment to improve lexical retrieval of content words in sentence context by promoting systematic retrieval of verbs and their thematic roles. The purpose of this study was to examine the effects of VNeST on Korean individuals with mild to moderate aphasia. Methods: Three Korean individuals with aphasia due to a stroke in the left hemisphere participated in the study. The treatment followed the steps of 1) naming of the target verbs, 2) generation of three agents or themes for target verb, 3) generation of corresponding agents or theme, 4) answering to wh-questions about agent-theme pairs, 5) semantic judgment of each sentence, and 6) naming of the target verbs. Multiple-baseline design across participants was employed. Effect sizes of the treatment were also obtained. Results: Results demonstrated medium to large effect sizes on trained verbs in all participants. They also presented generalization effects on untrained verbs. In addition, participants exhibited better performance on noun naming tasks, and aphasia quotient increased in the post-treatment phases compared to the pre-treatment phase. Conclusion: The current study suggested that the VNeST was effective for individuals with aphasia. The results were consistent with previous findings from English speaking individuals with aphasia. Further studies are required to validate the treatment efficacy by including more participants with various severity and types of aphasia.