Agreement between cognitive screening tools: a comparison of MoCA, ACE-III, M-ACE, and MoCA-MIS

Introduction Early detection of cognitive decline is critical, yet commonly used screening tools may yield divergent results. This study examined the alignment of four widely used instruments in a community-dwelling cohort.Method Seventy-nine participants (Mage = 71.20, SD = 6.29; 39 male, 40 female) were recruited from the general community and assessed under standardized laboratory conditions. Participants completed the Montreal Cognitive Assessment (MoCA) and the Addenbrooke’s Cognitive Examination-III (ACE-III), from which scores for the MoCA Memory Index Score (MoCA-MIS) and the Mini-Addenbrooke’s Cognitive Examination (M-ACE) were also calculated. Test agreement was examined using observed agreement and Cohen’s kappa, and score relationships were evaluated using Pearson correlations.Results All but one test pair (M-ACE vs MoCA-MIS) showed strong score correlations. However, agreement between MoCA and ACE-III for classifying participants as below threshold was only fair. MoCA identified twice as many participants as impaired compared with ACE-III, raising the possibility of either greater sensitivity or higher false-positive classification. Overall, 41% of participants (n = 32) scored below threshold on at least one measure, but only 6% (n = 5) were below threshold across all four. Of four participants with a prior mild cognitive impairment (MCI) diagnosis, only one, who had more pronounced deficits, scored below threshold in all tests.Conclusions Despite strong inter-test correlations, substantial divergence in classification outcome was observed, particularly between MoCA and ACE-III. Reliance on a single screening instrument risks misclassification, with implications for both over- and under-diagnosis. Greater harmonization between screening tools is needed to improve diagnostic consistency. Clinical practice should therefore combine multiple-instrument approaches, potentially including premorbid function, and interpret screening test scores cautiously. Comprehensive neuropsychological assessment may provide a more complete picture, particularly in cases where diagnostic confidence is low, although this is not routine practice in all services.