title: Visualization of e-Health Research Topics and Current Trends Using Social Network Analysis.
abstract: BACKGROUND
  E-health has been grown rapidly with significant impact on quality and safety of healthcare. However, there is a large gap between the postulated and empirically demonstrated benefits of e-health technologies and a need for a clearer mapping of its conceptual domains. Therefore, this study aimed to critically review the main research topics and trends of international e-health through social network analysis.
  
  
  METHODS
  Medical subject heading terms were used to retrieve 3,023 research articles published from 1979 through 2014 in the PubMed database. We extracted n-grams from the corpus using a text analysis program, generated co-occurrence networks, and then analyzed and visualized the networks using Pajek software. The hub and authority measures identified the most important research topics in e-health. Newly emerging topics by 4-year period units were identified as research trends.
  
  
  RESULTS
  The most important research topics in e-health are personal health records (PHR), health information technology, primary care, mobile health, clinical decision support systems (CDSS), and so on. The eight groups obtained through ego network analysis can be divided into four semantically different areas, as follows: information technology, infrastructure, services, and subjects. Also, four historical trends in e-health research are identified: the first focusing on e-health and telemedicine; the second, PHR and monitoring; the third, CDSS and alert; and the fourth, mobile health and health literacy.
  
  
  CONCLUSIONS
  This study promotes a systematic understanding of e-health by identifying topic networks, thereby contributing to the future direction of e-health research and education.
authors.affiliation: 1 Department of Nursing, Soonchunhyang University , Cheonan, Republic of Korea.
authors.forename: Youn-Jung
authors.initials: YJ
authors.lastname: Son
authors.forename: Senator
authors.initials: S
authors.lastname: Jeong
authors.forename: Byeong-Gwon
authors.initials: BG
authors.lastname: Kang
authors.forename: Sun-Hyung
authors.initials: SH
authors.lastname: Kim
authors.forename: Soo-Kyoung
authors.initials: SK
authors.lastname: Lee
mesh_terms: D020000:Decision Support Systems, Clinical / Q000639:trends*; D005544:Forecasting; D006801:Humans; D011787:Quality of Health Care; D056910:Republic of Korea; D012107:Research Design; D060756:Social Networking; D017216:Telemedicine / Q000639:trends*
keywords: e-health; mobile health; telehealth; telemedicine; telenursing