Mapping the landscape of cerebral amyloid angiopathy research: an informetric analysis perspective

To quantitatively analyse the research output and major trends in the field of cerebral amyloid angiopathy (CAA) over six decades, from 1954 to 2014, using advanced informetrics methods, we systematically identified CAA-related articles from PubMed, collected metadata and performed productivity analysis, copublication analysis, and network and content analysis over defined time periods. Linear regression was used to investigate these relationships. Changes in CAA research themes (2000-2014) were defined using a topic modelling technique. A total of 2340 CAA papers were published between 1954 and 2014. The mean number (3.03; 95% CI 2.62 to3.45; p<0.0001) and mean rate (0.13%; 95% CI 0.11% to 0.15%; p<0.0001) of CAA publications increased yearly. Analysis of copublication networks over 5-year periods from 1990 to 2014, revealed a great increase in the total number of connected investigators publishing on CAA (coefficient 16.74; 95% CI 14 to 19.49; p<0.0001) as well as the interactions between them (coefficient 73.53; 95% CI 52.03 to 89.03; p<0.0001). Further analysis of the network characteristics showed that in the past 15 years, copublication networks became not only larger, but also more connected and coherent. Content analysis identified 16 major CAA research themes and their differential evolution in the past 15 years, with the following main trends: (A) limited focus on vascular cognitive impairment; (B) a shift in emphasis towards neuroimaging, cerebral microbleeds and diagnostic aspects and away from pathological aspects; and (3) a reduced emphasis on basic biology apart from an increased focus on mouse models and perivascular drainage. Our study reveals the rapidly developing nature of the CAA research landscape, providing a novel quantitative and objective basis for identifying unmet needs and new directions. Our findings support the idea of a collaborative culture in the field, encouraging international research initiatives.