Detection of Cognitive Decline by the Montreal Cognitive Assessment in a Latin America Multi-Cohort Study: Normative scores regarding age and educational level

The aging population is growing, with a prevalence of cognitive decline (CD) expected to increase over the next decade, mainly affecting Latin America countries (LAC). The lack of appropriate context-based tools to detect cognitive decline (CD) may be a source of misinterpretation. The Montreal Cognitive Assessment (MoCA) is a recommended screening test to detect CD; however, it has commonly been used with a proposed cut off > 26. Our aim was to propose normative values based on a large sample from LAC to improve the detection of CD in our population. We collected data from Argentina, Brazil, Colombia, and Mexico participants who were classified as controls from the LARGE-PD consortium. A total of 781 individuals (38.54% male; mean age 55.2 ± 16.6 years), with a mean of 13.5 ± 5 years of education and a mean MoCA score of 24.2士4.1, were stratified by age and educational level (EL). DSM-V criteria were used to determine absence of CD. MoCA test v.7 was administered using a pen-and-paper format. ANOVA was used to detect differences in age and EL among countries. MoCA scores were compared using the Kruskal-Wallis test. Normative values for detecting CD were established as -1 standard deviation (SD) below the mean within each stratified group. The prevalence of CD was calculated by country and for the entire sample. Our proposed normative values adjusted for age and educational level demonstrated that the prevalence of CD decreased to 12%, compared with the 53.8% when using the cut-off of 26. Consequently, normal cognition increased to 88%. This finding improves the detection of cognitive decline through a more appropriate interpretation of MoCA score, considering the diversity of population of LAC. Working with normative values may enhance the allocation of resources to follow-up, monitoring and management in resource-limited settings.