Attention orienting in a spatial and a nonspatial task by healthy young and elderly subjects and by Alzheimer's disease patients

Attention orienting in a spatial (the Posner type) and a nonspatial (the Stroop type) task was examined in healthy young, healthy elderly, and patients with Alzheimer's disease (AD). The designs of the two tasks were comparable in terms of cue type, cue validity, and cue-to-target SOA. The effect sizes (Hedge's g) derived from the cost-plus-benefit measures of cue validity were used in the comparisons between tasks and among subject groups. The results: (1) aging and AD affected voluntary orienting by delaying the time by which the orienting effect developed to a reliable level and by depressing the extent of the effect, (2) aging and AD influenced involuntary orienting by delaying the time by which the orienting effect developed to a reliable level, by depressing the extent of the effect, and by reducing subjects ability to maintain the orienting effect, and (3) the effect of aging and AD on voluntary orienting tended to be for the nonspatial task than the spatial task, whereas their effect on involuntary orienting tended to be greater for the spatial task than the nonspatial task. It is suggested that spatial and nonspatial attention orienting are functionally similar, but may have different neuroanatomical substrates.