The objective of the present paper was to verify the occurrence of senile dementia in the city of Fortaleza, Brazil. A screening test, the Information, Memory and Concentration Test (IMC), was applied to 865 persons (65 years old and older). The Test includes questions on personal identification, recent and remote memory and concentration. Dementia was determined as a function of the total score obtained by the person in the test previously examined as far as sensitivity and specificity are concerned. The results were analysed according to age, sex and social strata. It was demonstrated a prevalence of dementia of 8.4% in the sample studied with no significant difference in the proportions of cases among people 75 years old or older (9.3%) as compared to the group younger, 65 to 74 years old, (7.5%). The percentage of dementia was similar between men (8.7%) and women (8.3%). It was verified a progressive increase in the frequence of dementia ranging from 5.2% for the higher social classes (A/B) to 6.9% and 10.3% for medium (C) and lower (D/E) ones respectively, with a significant difference between the social classes A/B and D/E. These results, however, should be seen with caution because of the percentage of refuse especially in the higher, A/B (19.3%) and lower D/E (9.3%) social classes.
