Insights From a Scoping Review and Bibliometric Analysis of Trends and Advances in Biomarker Research: The Role of MicroRNAs in Cognitive Decline Across Neurodegenerative Diseases

MicroRNAs (miRNAs) are small non-coding RNA molecules that negatively regulate gene expression and are implicated in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). This study aims to provide a bibliometric analysis of the most influential research on miRNAs related to cognitive decline in AD and PD. Searches were run in Scopus on July 23, 2024 (verification July 29, 2024) for records 2014-2021; journal indicators were retrieved from Clarivate Journal Citation Reports (JCR) at the time of extraction. Selection was based on total citations; citations per year were calculated for interpretation. The search initially identified 7,722 articles related to miRNAs and cognitive decline in AD and PD. After applying predefined inclusion and exclusion criteria, the top 100 most-cited articles, published between 2015 and 2021, were selected for detailed analysis. Citation metrics and bibliometric data were extracted and analyzed to determine trends, influential journals, key authors, and leading institutions. The analysis revealed a peak in publications in 2014, with 28 articles contributing to a total of 5,339 citations. Among the top 100 articles, 60 were classified as Citation Classics (≥100 citations), and 40 were identified as Hyperclassics (≥250 citations). The leading journals were Molecular Neurobiology, Progress in Neurobiology, and PLoS ONE, collectively accounting for 2,944 citations (14.7% of the total). Harvard Medical School emerged as the top contributing institution, with four highly cited articles totaling 683 citations (3.3% of the total). Geographically, the United States led the research landscape with 31 articles, representing 32.1% (6,593 citations) of the total citations. This bibliometric analysis highlights the significant role of miRNAs in cognitive decline related to AD and PD. Review articles comprised 65% of the Hyperclassics, emphasizing their impact in consolidating and advancing knowledge. The findings underscore the importance of continuous innovation, interdisciplinary collaboration, and global research efforts in the development of miRNAs as biomarkers for early diagnosis and monitoring of cognitive decline in neurodegenerative diseases.