Main Dimensions, Myriad of Assessment Tools and New Approaches for Early Detection of Subjective Cognitive Decline and Mild Cognitive Impairment: A Systematic Review

In an aging world with an increasing prevalence of neurodegenerative diseases that could benefit from early diagnosis and interventions, neuropsychological testing is key when defining cognitive profiles of middle aged and older people. Detecting subtle cognitive changes such as those referred to in subjective cognitive complaints - a clinical entity scarcely studied- and underdiagnosed early stages of Mild Cognitive Impairment is critical for early detection and preventive interventions in primary care settings. This systematic review analyzed empirical data (Pubmed database, between 2009 and 2024) from 21 papers with an exploratory, cross-sectional and prospective scope in this field. A part of screening tests (20%), a wide spectrum of neurocognitive tests was used to assess specific domains. Executive functions (25%), language (14%), and memory (14%) were the three most common, eligible for brief cognitive assessment, as compared to praxis (6%), intelligence (5%) and visual / visuospatial perception (4%). Interestingly, self or informant reports and the presence of neuropsychiatric symptoms (depression and anxiety) emerged as domains to be considered. A need for methodological consensus appeared as a strong limitation, even in those main dimensions, where MSE (51,6%), TMT A-B (29,4%), Semantic and fluency test (23,8%), BNT (28,6%), Stroop Test (17,6%), DST (17,6%), RAVLT (16,7%) and MoCA (12,9%) were the most common tools. However, stronger efforts to ensure greater specificity and sensitivity to early changes as well as consensus on which neuropsychological protocols/domains and clinical analysis should contain are needed to respond to the increasing mental health demands of the aging population.