What type of medical illustrations best improve understanding of scientific content? A systematic review.

The field of visual medical communication has extensively demonstrated the potential benefits of using images to communicate health and scientific concepts. However, it is still unclear which specific types of visuals enhance understanding for particular audiences. The main goal of this study is to identify trends in how style features, namely levels of realism and detail, affect the understanding of medical illustrations by different target audiences. A systematic review was conducted, searching the following scientific literature databases: APA PsycNet, Biomedcentral, DOAJ, EBSCO, ERIC, JSTOR, Pubmed, Science Direct, and Semantic Scholar. Twenty-six original research articles published between 1986 and 2023 were identified, with half of the studies conducted in the USA and South Africa. The current body of evidence supports the idea that simple medical illustrations - both schematic and realistic - may be more easily understood by audiences, particularly lay audiences. Nevertheless, realistic, more detailed illustrations may be more appropriate for individuals with higher health literacy or for medical professionals. This review also compiles practical tips for illustrators and communicators to create effective visual materials, as well as considerations regarding the role of medical illustrators in developing effective medical illustrations.