Selective attention in Alzheimer's disease: Analysis of errors in Zazzo's Cancellation Task

The analysis of performances of individuals with Alzheimer's Disease (AD) o n Cancellation Tasks provides useful information on the way they process th eir surrounding field, since these tasks require one to selectively attend to relevant features of the field while suppressing irrelevant ones. Incons istently with the hypothesis of a general inhibitory breakdown in AD which would have predicted a considerable number of crossed distracters in AD ind ividuals, previous results had shown that errors were predominantly omissio ns but rarely crossed distracters. However, our results on Zazzo's Cancella tion Task showed that by increasing the features shared by the target and d istracters, AD individuals also commit numerous crossed distractors. The re sults are interpreted in terms of inhibitory deficits. (C) 1999 Academic Pr ess.