Category fluency as a screening test for Alzheimer disease in illiterate and literate patients

Abstract

Brief cognitive tests are widely used for dementia screening, but are usually influenced by education. The present work aimed to determine education-adjusted cut-off scores and correspondent sensitivity (S) and specificity (Sp) values of the category fluency (CF) test (animals/min) as a screening tool for Alzheimer disease (AD). Eighty-eight patients with mild AD and 117 normal matched controls were evaluated. Patients and controls were divided into 4 groups according to educational level (illiterates, 1 to 3, 4 to 7, and > or =8 y) and were administered the CF test. In each group, cut-off values were determined using Receiver Operator Characteristic analysis. The areas under Receiver Operator Characteristic curves were 0.922/0.914/0.963/0.954, for the identification of AD among the groups of illiterates, 1 to 3, 4 to 7, and > or =8 years of education, respectively. The cut-off points for each group were 9 (S=90.5% and Sp=80.6%) for illiterates; 12 (S=95.2%% and Sp=80.0%) for 1 to 3 years; 12 (S=91.3% and Sp=91.9%) for 4 to 7 years, and 13 for those with > or =8 years (S=82.6% and Sp=100.0%). These results suggest that the CF may be a useful screening test for mild AD in different educational levels, with the need of using specific cut-off scores adjusted for each range of schooling.