Objective: To determine what change in the Modified Mini-Mental State Examination (3MS), a validated and widely used cognitive screening tool for which meaningful change scores have not been clearly characterized, should be considered meaningful.
Study design and setting: The 3MS was administered at baseline after 5 and 10 years, as part of the population-based Canadian Study of Health and Aging. We calculated Cohen's effect sizes to estimate detectable changes in 3MS screening scores over 5 and 10 years in this large and representative study sample.
Results: A total of 3,255 older adults who were community dwelling at baseline completed the 3MS as part of a screening interview at all three interviews. Mean 3MS score was 90.4 (standard deviation [SD] 6.9) at t(1), 89.1 (SD 8.2) at 5 years, and 85.8 (SD 13.0) at 10 years. A change of just over one point, over 5 and 10 years, represented a clinically detectable change with a medium effect size (Cohen's d=0.5).
Conclusions: Although a change of >or=1 point was clinically detectable, consideration of additional criteria for clinical meaningfulness suggested that a change of >or=5 points likely represents a clinically meaningful difference for groups, and is a reasonable choice of cutoff in studies using the 3MS to define cognitive change in individuals.