Objective: To estimate the prevalence of cognitive impairment in an elderly population-based cohort, using several Mini-Mental State Examination (MMSE) cut-off points recommended by Brazilian authors and to examine the percentile distribution of MMSE scores in the study population.
Method: A total of 1558 subjects aged>60 years (89.4% of the total), living in the city of Bambuí, MG, completed the MMSE and were included in the present study.
Results: The estimated prevalences of cognitive impairment varied from 13.2% to 27.0% depending on the cut-off point and agreement varied widely between them (kappa range: 0.38 to 0.88). Cut-off point 13/14 corresponded to the 5th percentile and 21/22 corresponded to the lower quartile of the MMSE score distribution.
Conclusion: In the absence of comparable cut-off points, percentile distributions are more adequate for population-based studies of elderly with low schooling level.