Influence of education on the neuropsychological assessment of the elderly: application and analysis of the results from the Mattis Dementia Rating Scale (MDRS)

Objective: To assess the influence of low education and illiteracy on the evaluation of dementia by the Mattis Dementia Rating Scale (MDRS). Method: We applied the MDRS to 62 normal elderly subjects (64-77 years), divided into five groups according to schooling, i.e., 15-16 years, 11-12 years, 8-9 years, 4 years, and illiterate. The MDRS covers the study of five subscales and the sum of their scores may represent the degree of cognitive impairment. Results: A significant difference (p < 0.05) in performance on this scale was observed among the subgroups in relation to education on 12 items, 5 subscales (illiterates < all other groups and 15-16 years > 4 and 8 years of schooling, p <= 0.001) and the total MDRS score (illiterates < all others and 4 and 8 years < 15-16 years, p < 0.001). No significant correlations where found for age and, regarding gender, the differences were significant in only one item Conclusion: Education interfered with individual performance on the MDRS. Illiteracy is a determinant factor of lower MDRS scores that could generate diagnostic errors.