Diagnostic validity of age and education corrections for the Mini-Mental State Examination in older African Americans.

OBJECTIVES

To investigate whether demographic (age and education) adjustments for the Mini-Mental State Examination (MMSE) attenuate mean score discrepancies between African-American and Caucasian adults and whether demographically adjusted MMSE scores improve the diagnostic classification accuracy of dementia in African-American adults over unadjusted MMSE scores.

DESIGN

Cross-sectional study.

SETTING

Community-dwelling adults participating in the Mayo Clinic Alzheimer's Disease Patient Registry and Alzheimer's Disease Research Center.

PARTICIPANTS

Three thousand two hundred fifty-four adults (2,819 Caucasian, 435 African American) aged 60 and older.

MEASUREMENTS

MMSE score at study entry.

RESULTS

African-American adults had significantly lower unadjusted MMSE scores (23.0 ± 7.4) than Caucasian adults (25.3 ± 5.4). This discrepancy persisted despite adjustment of MMSE scores for age and years of education using established regression weights or newly derived weights. Controlling for dementia severity at baseline and adjusting MMSE scores for age and quality of education attenuated this discrepancy. In African-American adults, an age- and education-adjusted MMSE cut score of 23/24 provided optimal dementia classification accuracy, but this represented only a modest improvement over an unadjusted MMSE cut score of 22/23. The posterior probability of dementia in African-American adults is presented for various unadjusted MMSE cut scores and prevalence rates of dementia.

CONCLUSION

Age, dementia severity at study entry, and quality of educational experience are important explanatory factors in understanding the existing discrepancies in MMSE performance between Caucasian and African-American adults. These findings support the use of unadjusted MMSE scores when screening older African Americans for dementia, with an unadjusted MMSE cut score of 22/23 yielding optimal classification accuracy.