Usefulness of 2 questions about age and year of birth in the case-finding of dementia.

To test the hypothesis that the efficacy of 2 simple questions commonly used in clinical practice, asking the age and year of birth of individuals, will be satisfactory to rule out cases of dementia.Population-based, longitudinal, prospective study focused on the incidence of dementia. In the baseline, a 2-phase procedure for identifying cases and noncases of dementia was implemented.Zaragoza, Spain.Individuals 65 years or older without previous diagnoses of dementia (n = 3613) drawn from the population-based random sample of the ZARADEMP project.Standardized instruments were used, including the Geriatric Mental State (GMS) and the History and Aetiological Schedule (HAS); cases were diagnosed according to DSM-IV criteria ("reference standard"). The simple cognitive test used in this study consists of the following 2 compulsory questions: "How old are you?" and "What year were you born?"The test was well accepted by the participants and took less than 30 seconds to complete. Compared with the "reference standard," validity coefficients for incorrect answers in both questions were as follows: sensitivity 61.2%, specificity 97.8%, positive predictive value 44.4%, negative predictive value 98.9%.This ultra-short test has very good specificity and negative predictive power. Its use to rule out cases of dementia might be generalized, as it has the best efficiency reported to date.