Number-stroop performance in normal aging and Alzheimer's-type dementia

The number-Stroop paradigm was used to investigate changes in the inhibitor y system and in numerical processing in healthy elderly and individuals wit h dementia of Alzheimer's type (DAT). The size-congruity effect (i.e., rela tive to neutral trials, incongruent pairs interfere and/or congruent pairs facilitate either numerical or physical comparison) was found in all groups , though the pattern of interference and facilitation varied across them. O verall, the selective attention breakdown was reflected by the increase in interference shown by the older group and the DAT group. On the other hand, the observation of a standard laterality effect and of automatic numerical processing in all groups suggests that access and retrieval of numerical i nformation is relatively resistant to cognitive deterioration. (C) 2001 Aca demic Press.