Practice effect and test-retest reliability of the Mini-Mental State Examination-2 in people with dementia

BACKGROUND: The Mini-Mental State Examination-Second Edition (MMSE-2) consists of three visions: a brief version (MMSE-2:BV), a standard version (MMSE-2:SV), and an expanded version (MMSE-2: EV). Each version was equipped with alternate forms (blue and red). There was a lack of evidence on the practice effect and test-retest reliability of the three versions of the MMSE-2, limiting its utility in both clinical and research settings. The purpose of this study was to examine the practice effect and test-retest reliability of the MMSE-2 in people with dementia. METHODS: One hundred and twenty participants were enrolled, of which 60 were administered with the blue form twice (i.e., the same-form group, [SF group]) and 60 were administered with the blue form first and then the red form (alternate-form group, [AF group]). The practice effect was evaluated using a paired t-test and Cohen’s d. The test-retest reliability was examined using the intraclass correlation coefficient (ICC). RESULTS: For the practice effects, in the SF group, no statistically significant differences were found for the MMSE-2:BV and MMSE-2: EV total scores and eight subtests (p = 0.061–1.000), except for the MMSE-2:SV total score (p = 0.029). In the AF group, no statistically significant differences were found for all three versions of the total scores and subtests (p = 0.106–1.000), except for the visual-constructional ability subtest (p = 0.010). Cohen’s d of all three versions’ total scores and subtests were 0.00–0.20 and 0.00–0.26 for SF group and AF group, respectively. For the test-retest reliability, ICC values for all three versions and eight subtests in SF and AF groups were 0.60–0.93 and 0.56–0.93, respectively. CONCLUSION: Our results demonstrated that the practice effect could be minimized when alternate forms of the MMSE-2 were used. The MMSE-2 had good to excellent test-retest reliability, except for three subtests (i.e., visual-constructional ability, registration, and recall). Caution should be taken when interpreting the results of visual-constructional ability, registration, and recall subtests of the MMSE-2. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-021-02732-7.