This chapter describes the development of research on aphasia in linguistics from 2000 to 2019. It discusses the various visualization methods used to study aphasia, such as fMRI and EEG. The chapter also explores the challenges and future directions of visualizing aphasia in linguistics.

1. Introduction

This chapter discusses the development of aphasia research in linguistics from 2000 to 2019, including the focus on treatment effectiveness, systematic reviews, and meta-analysis. It also introduces the use of CiteSpace as a visualization tool to analyze research evolution and identify emerging trends in the field of aphasia. The paper aims to summarize the knowledge in the domain of aphasia and orientate future research.

2. Materials and Methods

The chapter describes the data collection process, including the selection of datasets and the criteria used. The authors analyzed 3,004 papers and 61,150 references related to linguistic and language studies from 2000 to 2019. They employed CiteSpace to visualize the research areas and focus transition of the aphasia knowledge domain using document co-citation analysis. This method provides a quantitative basis for extracting a document co-citation network. The resulting network is composed of nodes and lines, with nodes representing cited references and lines representing their co-citation relations. The authors also utilized Betweenness Centrality to identify a pivot study and employed burst detection algorithms to predict possible future emerging trends.

3. Results

This chapter describes the document co-citation network of the aphasia knowledge domain in linguistics, which resulted in 431 nodes and 1,521 lines with a 4-year time slice. These clusters provide insight into the major areas and critical studies in the knowledge domain of aphasia from 2000 to 2019. The clusters can be divided into three aspects: language impairment in aphasia, aphasia therapy, and other directions associated with aphasia. The linguistic characteristics of aphasia describe impairments in lexical access, agrammatism, and naming deficits. Each cluster provides insights into specific areas such as lexical access, agrammatism and speech perception.

4. Pivotal-Point Studies in Terms of BC

This chapter discusses pivotal-point studies in terms of BC, a structural indicator to identify whether a scientific discovery established a “bridge” connection between previously disconnected knowledge clusters. The top five studies with high BC value are Thompson et al. (2012), Worrall et al. (2011), Thompson and Shapiro (2005), Pulvermüller et al. (2001), and Kagan et al. (2001), building connections in more than two clusters. These studies cover research topics such as dissociations between fluency and agrammatism in PPA, goals of PWA, remedies for PWAgr in terms of linguistics, CIAT, and SCA. These papers serve as pivotal points in the document co-citation network by connecting different research clusters in the knowledge domain of aphasia from a linguistic perspective.

5. Emerging Trends

This chapter describes the possible emerging research trends in the field of aphasia from 2000 to 2019. The trends include conversation or communication treatments focusing on the improvement of social participation and QOL of PWAs, the application of discourse produced by PWAs, primary progressive aphasia (PPA) variants, and the role of working memory (WM) in aphasia. These trends are considered to be the future research orientations in the field.

6. Discussion

This chapter discussed the research on language impairment in aphasia, including lexical access deficits and agrammatism. It also presented research on aphasia therapy, with a focus on neural plasticity and semantic features, as well as the integration of cognitive domains. The chapter explored the significance of communication for people with aphasia and other diseases such as stuttering. Additionally, it highlighted other topics associated with aphasia, such as apraxia of speech (AOS) and primary progressive aphasia (PPA), and the need for reliable diagnostic approaches to PPA.

7. Conclusion

The chapter concludes that aphasia has gained significant research attention, with a focus on improvements in communication. Key research topics include examining the effect of remedies, exploring primary progressive aphasia (PPA), assessing working memory (WM), and rehabilitation. Future attention is expected to be directed towards remedies targeting communication, discourse tasks, PPA variants, and the application of WM in aphasia. The study recommends an objective approach to visualizing and identifying major research specialties and emerging trends in aphasia research.