Alzheimer patients know their date of birth but not their age: A study on disorientation

Two experiments on orientation abilities were carried out to investigate whether differences in orientation performances are attributable to the nature of the information to be retrieved, ie to the necessity or not of its continuous updating. In the first experiment, a sample of 112 patients with „probable”︁ Alzheimer's disease (AD/pts) and 112 healthy controls were administered a 14‐item orientation inquiry. AD/pts were most impaired on items which required updating. This finding is interpreted in the light of the different attentional demands made by the two categories of items, namely variant and invariant, and the diminished attentional resources in AD/pts. In the second experiment, the same orientation inquiry was administered to 20 healthy young controls in a dual‐task design. The secondary task called for a continuous attention demanding reaction time. Results indicate that the items which required updating placed the greatest attentional demands. These findings lend support to the hypothesis raised to account for the outcome of the first experiment.