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RESEARCH ARTICLE
Asia Pac J Clin Trials Nerv Syst Dis 2020,  5:32

Epilepsy-related researches in Web of Science from 2011 to 2020: a bibliometric analysis


Editorial Office of Neural Regeneration Research

Date of Web Publication04-Jun-2020

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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2542-3932.285359

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  Abstract 


Background and objective: Epilepsy is a refractory disease of the nervous system. This article aimed to analyze the global trend of epilepsy research and the contribution of China to this research.
Methods: This paper used “epilepsy, seizure, status epilepticus, SUDEP” to retrieve epilepsy-related articles indexed in the Web of Science from 2011 to 2020, classified and analyzed the global epilepsy-related articles.
Results: This paper analyzed 65,270 articles on epilepsy research, showing that Epilepsy Behavior and Epilepsy Research were journals with the largest number of articles concerning epilepsy research in the world and China, respectively. The number of published epilepsy-related articles accounts for 5.43% of the global published articles and 3.29% of the published articles in China. The United States Department of Health Human Services and the National Institutes of Health jointly sponsored 15,713 of these articles, ranking first worldwide in the published epilepsy-related articles. Among 5206 articles published in China, 2696 articles (46.42%) were supported by the National Natural Science Foundation of China.
Conclusion: This study has reference significance for researchers in this field to understand the 10-year overview of epilepsy researches and formulate future research directions.

Keywords: bibliometric analysis; China; citation; epilepsy; Web of Science


How to cite this article:
. Epilepsy-related researches in Web of Science from 2011 to 2020: a bibliometric analysis. Asia Pac J Clin Trials Nerv Syst Dis 2020;5:32-6

How to cite this URL:
. Epilepsy-related researches in Web of Science from 2011 to 2020: a bibliometric analysis. Asia Pac J Clin Trials Nerv Syst Dis [serial online] 2020 [cited 2020 Nov 25];5:32-6. Available from: https://www.actnjournal.com/text.asp?2020/5/2/32/285359




  Introduction Top


Epilepsy is one of the most common chronic neurological diseases caused by excessive discharge of brain neurons, which is characterized by repeated and transient attacks of the central nervous system dysfunction (Fisher et al., 2005, 2014). Currently, approximately 50 million people worldwide are affected by epilepsy (Duncan et al., 2006). In addition, status epilepticus is a neurological emergency that requires timely evaluation and treatment (Duncan et al., 2006). Epilepsy is a clinical syndrome with various causes, complex mechanisms, and many influencing factors, but epileptic foci, abnormal potential, and synchronous discharge are common characteristics of all types of epilepsy (Kawai, 2015). In epilepsy, up to 10% of epilepsy adults and 20% of epilepsy children maintain status epilepticus (Hauser, 1999; Chin et al., 2004). In the past 10 years, research papers published in this field have shown the hotspot and status of scientific researchers.

Bibliometrics is an emerging field of information science, and can be used to deeply understand the knowledge structure in the academic field. Bibliometrics research can identify hotspots in specific research areas. Bibliometric analysis is usually utilized to determine academic literatures and landmark publications. Excellent articles of comprehensive bibliometric analysis has been published in several specialties, including intensive care medicine (Rosenberg et al., 2010), anesthesiology (Tripathi et al., 2011), radiology (Pagni et al., 2014) and neurosurgery (Bohl et al., 2007; Bohl and Ponce, 2017). Some recently published articles concerning bibliometric analysis have conducted more specific and in-depth bibliometric analysis in sub-specialties of neurology and neurosurgery, including aneurysmal subarachnoid hemorrhage (Alotaibi et al., 2016), severe craniocerebral trauma (Li et al., 2018) and Parkinson’s disease (Xue et al., 2018). Nevertheless, it is rare to understand and analyze global and Chinese epilepsy-related articles by bibliometrics. We conducted a bibliometric analysis of epilepsy-related articles indexed in the Web of Science from 2011 to 2020 to evaluate the status and progress of global and Chinese epilepsy research.


  Data and Methods Top


Epilepsy-related articles were retrieved in Web of Science on March 5, 2020. This study did not involve any human subjects and all data were from public databases, so the ethics committee did not review this study.

The key words were “epilepsy, seizure, status epilepticus, SUDEP.” This study summarized retrieval results from 2011 to 2020. Bibliometric indexes, including the total number of articles, the total cited frequency, the cited frequency of each article, h-index, research institutions, published journals and financial support, were extracted from the original retrieval data, and used for quantitative analysis of retrieved articles. The language was English. The types of literature were research articles and reviews. Meeting abstract, editorial material, letter, proceedings paper, correction, news item, and book chapter were excluded. All literature retrieval, records and downloads were completed on the same day to avoid changes in the number of literatures caused by daily database updates.

The flow chart of literature screening is shown in [Figure 1].
Figure 1: Literature screening flow chart.

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  Results Top


Epilepsy articles and growth trends published between 2011 and 2020

This study retrieved a total of 65,270 epilepsy-related articles indexed in the Web of Science from 2011 to 2020. [Figure 2]A shows that the number of articles concerning epilepsy increased with time. A total of 180 countries or regions participated in epilepsy-related research. The country with the largest number of publications was the United States (22,078 articles), followed by China (5808 articles) and United Kingdom (5570 articles) [Figure 2]B. Over time, the number of epilepsy articles from various countries has increased, but the number of publications in the United States has always ranked first. Except for the United States, the number of publications in China in 2011 is not much different from that of other countries. Since 2015, the number of publications was higher in China than in the other six countries Figure 2]C.
Figure 2: Epilepsy-related articles published globally and in China from 2011 to 2020.
Note: (A) Global number of epilepsy-related publications. (B) Sum of epilepsyrelated articles from the top 19 countries and territories. (C) Epilepsy-related articles published from the top eight countries.


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Citation and h-index analyses

The h-index is a mixed quantitative index, which can be used to evaluate the quantity and level of academic output of researchers. The h-index was proposed in 2005 by George Hirsch, a physicist at the University of California San Diego (Hirsch, 2005). The calculation of h-index is based on the number of papers of its researchers and the number of citations. It is generally believed that h-index can accurately reflect one’s academic achievements. The higher the h-index of a person, the greater the influence of his thesis is.

[Figure 3]A shows the number of articles with the highest citation rates in the top 12 countries. The total citation of American articles was 61,164 times, with an average of 228.22 citations per article; and h-index was 155. The total citation of Chinese articles was 5064 times, with an average of 194.77 citations per article; and h-index was 22.

Articles addressing epilepsy came from approximately 25,521 institutions worldwide. [Figure 3]B shows the names of the top 10 institutions with the largest number of articles published globally from 2011 to 2020. Of the ten institutions, fou r were from the United States, two from the United Kingdom, two from France, and the other two from Canada and Australia.
Figure 3: Citation and h-index analyses globally and in China.
Note: (A) Total citations, average citations per article, and h-index for epilepsyrelated articles from the top 10 countries. (B) Total citations, average citations per article, and h-index for epilepsy-related articles from the top 10 global institutions by publication volume. (C) Total citations, average citations per articles, and h-index for epilepsy-related articles from the top 10 Chinese institutions by publication volume.


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The University of London has become the biggest contributor to epilepsy research with 2584 articles, and the total citation was 61,592 times, and an h-index was 96, followed by University of California San Diego (2503 articles with 65,916 total citations and an h-index of 101), Harvard University (2273 articles with 52,148 total citations and an h-index of 91), and University College London (1920 articles with 47,120 total citations and an h-index of 79).

In China, 3678 institutions have participated in epilepsy related research. [Figure 3]C details the contribution of 10 Chinese institutions. Totally 537 articles related to epilepsy were published by Capital Medical University, with 3619 total citations and an h-index of 25, followed by Sichuan University (347 articles with 3201 total citations and an h-index of 28), and Central South University (293 articles with 2902 total citations and an h-index of 24). In recent years, Chinese institutions are working hard to improve and focus on transformative research in the field of epilepsy.

Study category analyses

Internationally, epilepsy-related articles can be found in 140 categories. As shown in [Figure 4]A, the most common category is clinical neurology, with 25,835 articles, accounting for 39.58%, followed by neuroscience (15,586 articles, accounting for 23.88%), psychiatry (6040 articles, accounting for 9.25%), pediatrics (5223 articles, accounting for 8.00%), and pharmacology/pharmacy (4764 articles, accounting for 7.30%).
Figure 4: Research categories globally and in China.
Note: (A) Research categories in global epilepsy research. (B) Research categories in Chinese epilepsy research.


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As exhibited in [Figure 4]B, the top 5 categories of Chinese articles are neuroscience/neurology (2838 articles, accounting for 48.86%), pharmacology/pharmacy (586 articles, 10.09%), basic experimental research (454 articles, 7.82%), biochemistry/molecular biology (386 articles, 6.65%), internal medicine (323 articles, 5.56%), and psychiatry (312 articles, 5.37%).

Publication journal and research funding agency analyses

Epilepsy-related articles indexed in Web of Science were published in 5197 journals, and 1060 journals published articles written by Chinese researchers. [Figure 5]A shows the top 10 journals with the largest number of articles. Epilepsy Behavior is the most active journal in epilepsy research, with 3547 articles published, accounting for 5.43%, followed by Epilepsia (2738 articles, 4.20%), Epilepsy Research (1705 articles, 2.61%), Seizure European Journal of Epilepsy (1690 articles, 2.59%). As displayed in [Figure 5]B, in China, Epilepsy Research published the most epilepsy research (191 articles, 3.29%), followed by Epilepsy Behavior (181 articles, 3.12%), Seizure European Journal of Epilepsy (163 articles, 2.81%), Medicine (143 articles, 2.46%), and PLoS One (104 articles, 1.79%).
Figure 5: Highly contributing journals and funding systems to epilepsy-related publications globally and in China.
Note: (A) Sum of publications, total citations, average citations per article, and h-index for epilepsy research journals worldwide. (B) Sum of publications, total citations, average citations per article, and h-index for epilepsy-related journals in China. (C) Top 10 funding systems contributing to global epilepsy research. (D) Top 10 funding systems contributing to epilepsy research in China.


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As shown in [Figure 5]C, globally, the United States Department of Health Human Services and the National Institutes of Health NIH USA co-supported the publication of 15,713 articles, ranking first in the world in the published epilepsy-related articles. As displayed in [Figure 5]D, the National Natural Science Foundation of China funded the largest number of articles in China, with 2696 articles published, accounting for 46.42%.

Analysis of most-cited epilepsy-related articles

[Tables 1] and [Tables 2] list the details of the top 10 highly cited articles on epilepsy in the world and China.
Table 1: The top 10 most frequently cited papers on epilepsy in the world

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Table 2: The top 10 most frequently cited papers on epilepsy in China

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Four of the most cited articles on epilepsy worldwide are reviews, and three of the most cited articles in China are reviews. The most cited articles in China were published after 2010, and the most cited articles from China were published in international cooperation.


  Discussion Top


This paper outlines the global development trajectory of epilepsy-related articles and summarizes the contributions of many countries worldwide to epilepsy research in the past 10 years.

In the past 10 years, the number of articles on global epilepsy research has increased dramatically. During the survey period, the number of articles on epilepsy research grew rapidly, which was consistent with the growth of articles in other neuroscience fields (Yeung et al., 2017a). Most of the articles on epilepsy in the first 10 years are from the United States. With the rapid development of science and technology, China also occupies a considerable position in epilepsy research. In recent years, the Chinese government has been supporting the development of neuroscience research. The number of projects supported by National Natural Science Foundation of China has been increasing year by year, which has greatly improved the quantity and quality of articles on epilepsy in China.

Only when the research results are published in the form of journal articles can they have an impact on professional workers.

Globally, 5197 journals have published articles related to epilepsy, and the 10 journals with the highest number of articles contributed 20.89% of the citations of published articles. Journals that publish more epilepsy articles may accumulate a larger number of cited articles, which may have a snowballing effect (Yeung et al., 2017b). Articles with higher impact factors may be cited more frequently (Lefaivre et al., 2011; Yeung et al., 2017b). These widely cited articles are more familiar to most epilepsy researchers, which will play a scientific guiding role in understanding the key information in this field.

Despite changes in research topics, the countries and institutions that published the most articles on epilepsy still came from the United States, the United Kingdom, Germany, Italy, Canada and China. In 2011, except for the United States, the number of published articles on epilepsy in China is not much different from that in other countries. Since 2015, China’s epilepsy research has made great progress, with the number of publications ranking the second in the world. Recently, the rapid growth of China’s economic strength has greatly promoted the in-depth attention of Chinese scholars to the hot spots of epilepsy research. The total number of articles from China increased sharply, and the citation and h-index also increased significantly. Regarding types of research disciplines, China has published many articles focusing on basic research. Few international journals related to epilepsy are founded by Chinese institutions. If Chinese publishing organizations can create some excellent international journals related to epilepsy, it may attract international submissions and encourage academic exchange.

There are also limitations in bibliometric analysis. Firstly, bibliometric analysis cannot measure the validity or scientific quality of each published article. Highly cited articles are not necessarily of high scientific quality. The number of citations depends on many factors, including the influence of journals, article types, research models and self-citation rate. Secondly, the delay of articles indexed in Web of Science may also lead to research bias. Finally, Web of Science mainly includes articles written in English, excluding many non-English articles. These will also affect the accuracy of evaluating research trends.

This study provides a perspective on the trajectory of publications and published articles for epilepsy researchers, and illustrates that this is a research field with more development prospects.

The most frequent categories of epilepsy-related articles are in neuroscience/neurology. Epilepsy Behavior is the journal with the largest number of published articles on epilepsy. Research institutions and research funding agencies from North America and Europe are the core research forces in this field. Among them, the United States has the largest number of published articles, and China has gradually become an important force for international epilepsy research and article publication. This bibliometric analysis is of great significance for epilepsy research and article publication.

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  References Top

1.
Alotaibi NM, Nassiri F, Badhiwala JH, Witiw CD, Ibrahim GM, Macdonald RL, Lozano AM (2016) The most cited works in aneurysmal subarachnoid hemorrhage: a bibliometric analysis of the 100 most cited articles. World Neurosurg 89:587-592.  Back to cited text no. 1
    
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Bohl MA, Ponce FA (2017) Assessing the relevancy of highly cited works in neurosurgery. Part I: the 100 most relevant papers in neurosurgical journals. World Neurosurg 104:927-938.  Back to cited text no. 2
    
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Bohl MA, Turner JD, Little AS, Nakaji P, Ponce FA (2017) Assessing the relevancy of “citation classics” in neurosurgery. Part II: foundational papers in neurosurgery. World Neurosurg 104:939-966.  Back to cited text no. 3
    
4.
Chin RF, Neville BG, Scott RC (2004) A systematic review of the epidemiology of status epilepticus. Eur J Neurol 11:800-810.  Back to cited text no. 4
    
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Fisher RS, Acevedo C, Arzimanoglou A, Bogacz A, Cross JH, Elger CE, Engel J Jr, Forsgren L, French JA, Glynn M, Hesdorffer DC, Lee BI, Mathern GW, Moshe SL, Perucca E, Scheffer IE, Tomson T, Watanabe M, Wiebe S (2014) ILAE official report: a practical clinical definition of epilepsy. Epilepsia 55:475-482.  Back to cited text no. 6
    
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Fisher RS, Van Emde Boas W, Blume W, Elger C, Genton P, Lee P, Engel J Jr. (2005) Epileptic seizures and epilepsy: definitions proposed by the International league against epilepsy (ILAE) and the International bureau for epilepsy (IBE). Epilepsia 46:470-472.  Back to cited text no. 7
    
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Hauser WA (1990) Status epilepticus: epidemiologic considerations. Neurology 40:9-13.  Back to cited text no. 8
    
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Hirsch JE (2005) An index to quantify an individual’s scientific research output. Proc Natl Acad Sci U S A 102:16569-16572.  Back to cited text no. 9
    
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Pagni M, Khan NR, Cohen HL, Choudhri AF (2014) Highly cited works in radiology: the top 100 cited articles in radiologic journals. Acad Radiol 21:1056-1066.  Back to cited text no. 13
    
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Tripathi RS, Blum JM, Papadimos TJ, Rosenberg AL (2011) A bibliometric search of citation classics in anesthesiology. BMC Anesthesiol 11:24.  Back to cited text no. 15
    
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
 
 
    Tables

  [Table 1], [Table 2]



 

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