It is estimated that a sample of 500 patients (250 with AD and 250 with FTD) and 200 controls (700 individuals in total) will be sufficient to corroborate the hypothesis that permits validation of the new diagnostic test. The sample size estimate is based on a hypothesis of non inferiority between the new test and the test used in normal clinical practice, expecting a 10% delta of the 75% validity, sensitivity and specificity indices with an alpha error of 0.05 and a beta error of 0.20.