Improving Cognitive Assessment Utility in Community Settings: Stratified Normative Data and Age-Specific Score Conversions between the MoCA-J and MMSE in Community-Dwelling Older Adults

Background Cognitive tests such as the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE) are widely used to evaluate cognitive function. Given the various constraints on cognitive assessment in community settings, score conversion between the MoCA and MMSE has gained attention as a means of maximizing information while minimizing burden. With rapid population aging, scalable and valid screening is critical for public health, dementia prevention, and resource allocation. When evaluating community-dwelling older adults, demographic variables, including age, sex, and educational attainment, must be considered. However, stratified normative data remain scarce, and, to our knowledge, no study has yet provided age-stratified score conversions between these two tests. Methods We analyzed pooled data from 3,565 older adults across three population-based cohorts in Japan, representing suburban, mountainous, and metropolitan regions, and encompassing diverse medical and educational backgrounds. We developed stratified normative data for the Japanese versions of the Montreal Cognitive Assessment (MoCA-J) and the Mini-Mental State Examination (MMSE). We then constructed bidirectional score-conversion tables using equipercentile equating with log-linear smoothing, which allowed us to evaluate scores across age, sex, and educational attainment. Results We developed stratified normative data and equipercentile-based score conversion tables between the MoCA-J and MMSE in community-dwelling older adults. The MoCA-J exhibited greater variability and a stronger negative correlation with age than the MMSE. Score conversion differed notably by age group, with MMSE scores displaying a ceiling effect. For example, a MoCA-J score of 22 corresponded to an MMSE score of 27. Incorporating age-specific conversions enhanced cross-tool comparability and improved interpretability across demographic strata in both clinical and research contexts. Conclusions The association between MoCA-J and MMSE scores varied according to demographic factors. Our findings highlight the limitations of applying a single clinical cut-off and support the use of stratified normative data and age-specific conversion tables to improve score interpretation. In community-based screening settings, such tools may enhance specificity, reduce misclassification, and support tailored follow-up. Stratified norms and age-specific conversions can be integrated into community screening, primary care, and municipal health programs through look-up tables or calculator tools.