Sudden unexpected death in epilepsy (SUDEP): A bibliometric analysis

Objective: The literature on sudden unexpected death in epilepsy (SUDEP) has been evolving at a staggering rate. We conducted a bibliometric analysis of the SUDEP literature with the aim of presenting its structure, perfor-mance, and trends.Methods: The Scopus database was searched in April 2023 for documents explicitly detailing SUDEP in their title, abstract, or keywords. After the removal of duplicate documents, bibliometric analysis was performed using the R package bibliometrix and the program VOSviewer. Performance metrics were computed to describe the liter-ature's annual productivity, most relevant authors and countries, and most important publications. Science mapping was performed to visualize the relationships between research constituents by constructing a country collaboration network, co-authorship network, keyword co-occurrence network, and document co-citation network.Results: A total of 2140 documents were analyzed. These documents were published from 1989 onward, with an average number of citations per document of 25.78. Annual productivity had been on the rise since 2006. Out of 6502 authors, five authors were in both the list of the ten most productive and the list of the ten most cited authors: Devinsky O, Sander JW, Tomson T, Ryvlin P, and Lhatoo SD. The USA and the United Kingdom were the most productive and cited countries. Collaborations between American authors and European authors were particularly rich. Prominent themes in the literature included those related to pathophysiology (e.g., cardiac arrhythmia, apnea, autonomic dysfunction), epilepsy characteristics (e.g., epilepsy type, refractoriness, antisei-zure medications), and epidemiology (e.g., incidence, age, sex). Emerging themes included sleep, genetics, ep-ilepsy refractoriness, and non-human studies.Significance: The body of literature on SUDEP is rich, fast-growing, and benefiting from frequent international collaborations. Some research themes such as sleep, genetics, and animal studies have become more prevalent over recent years.