The “Zoom Lens” of Focal Attention in Visual Search: Changes in Aging and Alzheimer's Disease

Eye fixations were analyzed in two regions of interest (ROIs, central fixation and peripheral target locations) in 9 patients with mild AD, 9 cognitively intact age-matched control subjects, and 9 young controls, while they searched for a target object in a radial array that contained from 1 to 6 stimuli. Contrasted with young subjects, the search strategy of older controls and, to a greater extent, AD patients showed an increase in the average number and duration of peripheral fixations. Reduced efficiency of visual search in AD may be contributed to by reduced ability to dynamically adjust the attentional zoom, coupled with the inability to disengage attention from peripheral targets.