3.1 Publication and Citation Analysis
As can be seen from Fig. 2, the annual publication volume and citation volume of the WoSCC database show an overall upward trend from 2012 to 2022. Prior to 2016, the research on post-stroke depression was relatively slow, with no more than 250 papers published each year and no more than 3,000 papers cited each year. However, the number of annual publications and citations had gradually increased after 2016.
In 2021, the annual publication volume reached 461 and the number of citations reached a peak of 12,351,means that there were more and more relevant studies in this field.
3.2 Country/Region analysis
The top 10 countries/regions in the WoSCC database by the number of articles on PSD were shown in Table 1. The top three countries in the field of PSD were China (26.52%), the United States (22.58%) and Australia (8.26%), accounting for about 57.36% of the total. The United States was the country with the highest Total citations and H-index, while the country with the highest Average citations per article is Italy.
Table 1
Top 10 countries/regions with publications on post-stroke depression.
Rank | Countries/Regions | Article counts | Percentage (n/3268) | Total citations | Average citations per article | H-index | TLS |
---|
1 | China | 867 | 26.52% | 8926 | 10.3 | 37 | 256 |
2 | USA | 738 | 22.58% | 16438 | 22.21 | 58 | 509 |
3 | Australia | 270 | 8.26% | 6220 | 23.04 | 38 | 350 |
4 | England | 245 | 7.49% | 7554 | 30.83 | 43 | 305 |
5 | Germany | 214 | 6.54% | 6498 | 30.36 | 41 | 259 |
6 | South Korea | 172 | 5.26% | 2635 | 15.32 | 27 | 115 |
7 | Canada | 172 | 5.26% | 4328 | 25.16 | 37 | 166 |
8 | Netherlnds | 150 | 4.58% | 3739 | 24.93 | 32 | 164 |
9 | Italy | 132 | 4.03% | 4638 | 35.14 | 32 | 174 |
10 | Japan | 118 | 3.61% | 1527 | 12.94 | 21 | 89 |
Figure 3A was a map of international cooperation between countries/regions, the thicker the lines between two countries indicate the closer cooperation. As the graph shown, countries such as China, the United States and Australia were more closely connected with other countries. Figure 3B was the country's citation network visualization map. Countries with total link strength (TLS) over 300 were USA (TLS = 509), Australia (TLS = 350) and England (TLS = 305), indicated that these three countries were more influential internationally. Overall, China, USA and Australia were the major international contributors to PSD research, with the largest number of publications and higher quality papers. Although the number of publications in China was relatively high, the quality of publications, as well as research in this field, needs to be improved.
3.3 Institutional Analysis
The top 10 institutions with the publications’ number were illustrated in Table 2. China, Australia and Canada had the most active institutions in the field of PSD research. Capital Medical University, University of Melbourne, University of Toronto and University of Western Australia were the top four institutions with the largest number of published papers, and University of Toronto had the highest number of citations and H-index.
Figure 4(A) was an institutional network collaboration diagram created using CiteSpace. Each In this graph, different institutions were represented by different nodes, with darker nodes indicating later active years. Capital Medical University and Harvard University had the highest centrality (both 0.13), followed were University of Toronto and Chinese University of Hong Kong (both 0.12). When the centrality value is greater than or equal to 0.1 means that the node is a key node of the network graph. That means these four universities have an important position in institutional cooperation. The institution's citation network visualization map was created by VOS viewer, as shown in Fig. 4(B), with 2699 links and 402 nodes, forming 14 clusters of different colors. University of Western Australia (TLS = 182), University of Melbourne (TLS = 180) and University of Toronto (TLS = 126) were the top three institutions with the highest TLS.
Table 2
The 10 institutions that published most articles.
Rank | Institutions | Countries/Regions | Article counts | Total citations | Average citations per article | H-index |
---|
1 | Capital Medical University | China | 59 | 787 | 13.34 | 15 |
2 | University of Melbourne | Australia | 58 | 1037 | 17.28 | 18 |
3 | University of Toronto | Canada | 57 | 1684 | 26.73 | 23 |
4 | University of Western Australia | Australia | 51 | 1173 | 20.58 | 18 |
5 | Chinese University of Hong Kong | China | 51 | 832 | 16.31 | 17 |
6 | Wenzhou Medical University | China | 51 | 556 | 10.69 | 15 |
7 | Maastricht Univ | Netherlands | 41 | 764 | 18.19 | 14 |
8 | Kings Coll London | England | 40 | 2531 | 55.02 | 23 |
9 | Harvard Med Sch | USA | 40 | 798 | 19.95 | 14 |
10 | Harvard Univ | USA | 34 | 2813 | 29.93 | 28 |
3.4 Funding Agency Analysis
The top 10 funding agencies which were supporting researches on PSD were listed in Table 3, and United States Department of Health Human Services (316), the National Institutes Of Health (306) and the National Natural Science Foundation Of China (300) were the top three. The top three funding agencies for post-stroke depression disease support far more than any other agency. By country, the United States China and the European Union funded the most publications.
Table 3
Top 10 funding agencies for PSD research
Rank | Funding Agencies | Number of Publications | Countries/Regions |
---|
1 | United States Department Of Health Human Services | 316 | USA |
2 | National Natural Science Foundation Of China | 300 | China |
3 | European Commission | 131 | European |
4 | National Institute Of Neurological Disorders Stroke | 114 | USA |
5 | National Health And Medical Research Council Nhmrc Of Australia | 63 | Australia |
6 | Canadian Institutes Of Health Research | 51 | Canada |
7 | German Research Foundation | 51 | Germany |
8 | Medical Research Council | 46 | England |
9 | Uk Research Innovation | 46 | England |
10 | National Research Foundation Of Korea | 46 | South Korea |
3.5 Author Analysis
The top 10 authors published a total of 299 articles on post-stroke depression, accounting for 9.14% of the total publication volume, see Table 4. Five of the top 10 authors were from China, namely Wang J, He JC, Tang WK, Zhang Y, Liu Y;, three from Korean namelyCho KH, Kim JS, and Kim JM. Among these authors, Ungvari GS and Wang J co-authored three articles, namely "Association between schizophrenia and violence among Chinese female offenders" and "Nurses' work-related stress in China: a comparison" between psychiatric and general hospitals" and "The MacArthur Competence Assessment Tools for assessing decision-making capacity in schizophrenia: A meta-analysis".
Figure 5(A) was a co-citation network graph of authors who had been cited at least 20 times, with a total of 957 nodes, 148,077 links and 5 clusters. Robinson RG (TLS = 30719), Hackett ML (TLS = 30477) and Dreier JP (TLS = 21729) had the highest TLS. The co-author citation analysis visualization graph, shown in Fig. 5(B), contains a total of 10,879 nodes, 10,879 links and 8 clusters. The nodes in this graph represent authors, the difference between the nodes in Fig. 5(A) and Fig. 5(B) was that in Fig. 5(B), the collaboration between authors determined the links between nodes. Hackett ML (TLS = 1439), Dreier JP (TLS = 1222) and Ungvari GS (TLS = 745)were the top 3 authors with the highest TLS, who were at the center of the partnership. Overall, the nodes of the network graph were scattered, indicating that the collaboration between authors in this field was not close.
Table 4
Top 10 authors with the most published papers about PSD
Rank | Author | Count | Countries/Regions | Institutions | H-index | Toyal citations |
---|
1 | Ungvari GS | 37 | Australia | Univ Notre Dame Australia | 15 | 638 |
2 | Wang J | 33 | China | Affiliated Hosp Youjiang Med Univ Nationalities | 12 | 537 |
3 | He JC | 32 | China | Wenzhou Med Univ | 11 | 325 |
4 | Tang WK | 32 | China | Chinese Univ Hong Kong | 13 | 474 |
5 | Zhang Y | 32 | China | Shanghai Jiao Tong Univ | 10 | 276 |
6 | Cho KH | 28 | South Korea | Kyung Hee Univ | 15 | 628 |
7 | Dreier JP | 27 | Germany | Charite Univ Med Berlin | 18 | 1225 |
8 | Liu Y | 27 | China | Shanghai Univ Tradit Chinese Med | 7 | 134 |
9 | Kim JS | 26 | South Korea | Univ Ulsan | 11 | 427 |
10 | Kim JM | 25 | South Korea | Chonnam Natl Univ | 14 | 544 |
The top 10 journals by publication volume from 2012 to 2022 were listed in Table 5, and most of them from the United States. The journal with the most publications was Journal of stroke cerebrovascular diseases, followed were Stroke and Topics in stroke rehabilitation, Stroke had the highest impact factor (IF). The IF of the top 10 journals range from 1.897 for Topics in stroke rehabilitation to 7.19 for Stroke according to Journal Citation Reports (JCR) 2022. The visualization of co-citation analysis of journals was shown in Fig. 6(A). The top three journals with the highest TLS were Stroke (TLS = 853), Journal of stroke cerebrovascular diseases (TLS = 814) and International journal of stroke (TLS = 805). Figure 6(B) show a double-map overlay of all academic journals, the right and left side of the map represented the cited and citing journals respectively, the colored lines represented the citation relationship between the citing journals and the cited journals. The entire graph can show the complete citation process. The length of the vertical axis was determined by the number of papers published in the journal, and the length of the horizontal axis was determined by the number of authors.The statistical results shown that Medicine, Medical and Clinical were the three major fields that published articles focus on, while the cited journals were mainly published in the fields of Psychology, Education and Social.
Table 5
Top 10 journals by publication volume between 2012 and 2022
Rank | Journal title | Countries/Regions | Article Counts | Percentage(N/3268) | IF(2022) | Quartile in category | H-index |
---|
1 | Journal of stroke cerebrovascular diseases | USA | 131 | 4.00% | 1.787 | Q4 | 22 |
2 | Stroke | USA | 100 | 3.05% | 7.19 | Q2 | 33 |
3 | Topics in stroke rehabilitation | USA | 84 | 2.57% | 1.897 | Q3 | 19 |
4 | Plos one | USA | 68 | 2.08% | 2.74 | Q2 | 25 |
5 | Medicine | USA | 64 | 1.95% | 1.552 | Q4 | 10 |
6 | Disability and rehabilitation | England | 63 | 1.92% | 2.222 | Q2 | 19 |
7 | Journal of affective disorders | Netherland | 60 | 1.83% | 3.892 | Q3 | 19 |
8 | Frontiers in neurology | Switzerland | 59 | 1.80% | 2.889 | Q3 | 13 |
9 | Neuropsychiatric disease and treatment | New Zealand | 46 | 1.40% | 2.157 | Q4 | 10 |
10 | Internationaljournal of stroke | England | 43 | 1.31% | 4.882 | Q3 | 20 |
3.6 Bibliography Analysis
A visualization of the literature co-citation network generated by the VOS viewer in Fig. 7(A), and the top 10 most-cited articles of PSD research were listed in Table 6, with 65,349 links and 587 nodes, forming 6 clusters of different colors. In these clusters, the total link strength to other cited references was calculated, and the highest TLS was an article published in 2005 by Hackett, ML et al. (TLS = 4734), followed ones were Ayerbe L et al. (TLS = 4734)., Hackett ML et al. (TLS = 4645, 2014), and Robinson RG et al. (TLS = 3955, 2016),. Two of the 10 articles were published on Stroke, and four of them were published between 2013 to 2017. The most cited article of PSD was published by Hackett, ML et al. about understanding the predictors of stroke-related depression that may lead to better treatment, including prevention and treatment.
The top 20 references with the strongest citing outbreaks in the PSD study were shown in Fig. 7(B). Among them, the two most explosive articles with strengths over 30 were: Natural history, predictors and outcomes of depression after stroke: Systematic review and meta-analysis which was published by Ayerbe, L et al. in 2013;and Post-stroke depression: Mechanisms and pharmacological treatment, which was published by Villa, RF et al. in 2018. The primary predictors of depression were identified in the first article, requiring intervention for PSD and its underlying outcomes. The second article had a bidirectional association between depression and stroke, and related research on the mechanisms and drug treatment of PSD. Both articles contributed significantly to post-stroke depression, making them with the strongest outbreaks. Robinson RG et al. and Hackett ML et al. each published an article that broke out in 2008, and the most recent outbreak occurred in 2016, and it continued to today.
Table 6
Top 10 most-cited articles of PSD research
Rank | Title | Total citations | First author | Publication Year | Journal |
---|
1 | Frequency of depression after stroke: an updated systematic review and meta-analysis of observational studies | 4645 | Hackett, ML | 2014 | International Journal Of Stroke |
2 | Post-Stroke Depression:A Review | 3955 | Robinson,RG | 2016 | Cerebrovascular Diseases |
3 | Natural history,predictors and outcomes of depression after stroke:systematic review and meta-analysis | 4669 | Ayerbe,L | 2013 | British Journal Of Psychiatry |
4 | Predictors of depression after stroke-A systematic review of observational studies | 4734 | Hackett,ML | 2005 | Stroke |
5 | The hospital anxiety and depression scale | 2913 | Zigmond,A S | 1983 | Health And Quality Of Life Outcomes |
6 | Measurements of acute cerebral infarction:a clinical examination scale | 2305 | Brott,T | 1989 | Stroke |
7 | "Mini-mental state".A practical method for grading the cognitive state of patients for the clinician | 2114 | Folstein,M F | 1975 | Journal Of Psychiatric Research |
8 | The hospital anxiety and depression scale | 2219 | Zigmond,A S | 1965 | Health And Quality Of Life Outcomes |
9 | A rating scale for depression | 2186 | Hamilton,m | 1960 | Journal Of Neurology Neurosurgery And Psychiatry |
10 | The hospital anxiety and depression scale | 2272 | Zigmond,A S | 2017 | Acta Psychiatrica Scandinavica |
3.7 Keyword Analysis
3.7.1 Keyword Time Evolution Analysis
The evolution of keywords in time series was an important basis for the development of this field in different time periods, and could predict the future research direction (Li et al., 2022). Figure 8 shown the bubble chart of keywords of high frequency topics from 2012 to 2022. By sorting and combining keywords and similar keywords, while retaining the most representative topics in the field of PSD research, high-frequency keywords in the field of PSD research were finally summarized into 12 hot topics.The size and color of the bubbles clearly indicate the evolution of keywords over the years. Therefore, the topics can be divided into three categories: the first category includes: "quality of life", "risk factor", "symptom", "predictor" and "risk", related to the first category of hot topic keywords. There were more and more articlesdepending on the status quo shown by the icon, these topics may receive more attention in the future. The second category included "prevalence", "scale" and "meta analysis". The frequency of occurrence first maintained an upward trend, and entered a stable period after 2020. The frequency fluctuated slightly in recent years, indicating that it had still received corresponding attention in recent years. The third category was divided into "cognitive impairment", "recovery", "disorder", and "rehabilitation". In the past 4 to 5 years, there had been a downward trend, indicating that the degree of attention to this topic haddecreased significantly.
3.7.2 Keyword co-occurrence analysis
In bibliometrics, keywords are a very important part, and keyword co-occurrence analysis can reveal changing research topics and development trends(Wang et al., 2022). The density visualizations generated by keyword co-occurrence more than 10 times were shown in Fig. 9(A). The higher the frequency of the keyword, the darker the color. 385 keywords were appeared as nodes, with the exception of "brush strokes" and "depression" being included in the search terms. The most frequently occurring keywords were "post stroke depression", "depression", "ischemic-stroke" and "predictors". The overlay visualization map of keywords was shown in Fig. 9 (B), where the keywords that appear more than 30 times at the same time are represented by 135 nodes. In the VOS viewer, different colors are used to label keywords based on the average year (AAY) of the keyword. Blue indicates the keyword that appeared earlier in the time frame, green indicates the second keyword, and yellow indicates the most recent keyword.
3.7.3 Keyword Cluster Analysis
The keyword co-occurrence graph was performed basis on Cluster analysis. The more nodes the cluster contains, the smaller the cluster number. Module value (Q value) and average contour value (S value) were used as evidence for judging the effect of graph clustering (Wu et al., 2022).Generally, Q value > 0.3 means the clustering structure was significant; S value > 0.7means the clustering result is convincing. LLR model was used in this study to perform cluster analysis on keywords, as shown in Fig. 10, Q value = 0.418, S value = 0.7317, and the clustering results could be considered significantly .
3.7.4 Keyword Emergence Analysis
This study listed the top 20 emergent keywords, as shown in Fig. 11. The keyword with the highest emergent intensity was “trial” (intensity = 9.61), followed were “follow up” (intensity = 7.7) and “community” (intensity = 6.12). "follow up", "infarction", "vascular depression" and "mood disorder" were the earliest emergent keywords, and the emergent keywords from 2020 to 2022 were "guideline", "cohort study", "update" and " statement". The graph show that a total of 8 keywords were still in the ongoing emergent phase.