Global mapping of early diagnostic tools for Alzheimer’s disease: Integrating bibliometric analysis, SWOT strategy, and a novel Relative Effectiveness Index

Abstract

Alzheimer’s disease (AD) remains a major cause of dementia worldwide, but early detection strategies are diverse and often context-specific. This study aimed to map early diagnostic modalities for AD, assess their coverage across populations and comorbidities, evaluate their relative effectiveness, and examine their strategic feasibility using an integrated bibliometric–SWOT approach. We analyzed Scopus-indexed studies published from 2015 to 2025 and classified them by primary modality, supporting techniques, target population, and comorbidities. A novel Relative Effectiveness Index (REI) and adjusted REI were developed to evaluate 108 modality–population–comorbidity combinations. Keyword co-occurrence analysis identified major thematic clusters, while chord diagrams and SWOT analysis illustrated methodological pairings and contextual feasibility across high-income countries (HICs) and low- and middle-income countries (LMICs). Data indicated that biomarkers and neuroimaging were predominantly applied in elderly populations and in comorbidities such as Parkinson’s disease, diabetes, and stroke. Scoring tools were most common in studies involving depression and cardiovascular disease, whereas functional tests were least used overall, with limited application in Parkinson’s disease and epilepsy. Blood-based methods and machine learning were frequently paired with biomarkers and neuroimaging, reflecting a shift toward non-invasive and precision diagnostics. Thematic clustering highlighted research concentrations on neurodegenerative mechanisms, AI-based neuroimaging, and blood biomarker discovery. Adjusted REI was highest for neuroimaging in elderly populations (1.03), while machine learning–integrated approaches consistently outperformed others across modalities (adjusted REI>1.1). In contrast, combinations involving younger populations, anthropometric methods, and some comorbidities showed little or no supporting evidence. SWOT analysis indicated that scoring tools remain accessible and interpretable, whereas biomarker- and neuroimaging-based strategies offer greater diagnostic precision but face implementation barriers, particularly in LMICs. Overall, this study provides an integrative evidence map of early AD detection, highlighting both well-supported strategies and critical evidence gaps.