Factor structure and explanatory variables of the Mini-Mental State Examination (MMSE) for elderly persons in Taiwan

The Mini-Mental State Examination (MMSE) is commonly used in studies and clinical assessment of cognitive functioning. The purpose of this study was to examine the factor structure and variables explaining the scores of the MMSE in elderly persons in Taiwan, in order to provide a reference for instrument selection and data collection for clinicians and researchers.

Secondary data from an epidemiologic study that included 1,442 randomly selected subjects aged 64 to 98 with an average age of 72.6 years were used. Males comprised 57.1% of the sample, and females 42.9%. Exploratory and confirmatory factor analysis and covariance structure modeling were used to analyze the data.

In the cross validation of the covariance structure modeling, 50.1% of the variance in simple processing, 86.9% in complex processing, and 66.9% in memory/attention were explained. Better education background predicted better score in complex processing ability (path coefficient = .860). Greater independence in self-care ability predicted better scores in simple processing (path coefficient = -.716) and memory/attention (path coefficient = -.811).

The results of this study indicate that items in the MMSE measuring complex processing ability including writing, reading and obeying, and copy design are seriously biased by educational background, and that the remaining items are better indicators of the subject's cognitive functioning for elderly persons in Taiwan. In our model, self-care ability was strongly related to cognitive functioning as measured by the MMSE, especially for items in the factors of simple processing (registration, naming, repetition, and commanding) and attention/memory (orientation to place and time, attention, and recall).