SELECTIVE ATTENTION IN AGE-ASSOCIATED MEMORY IMPAIRMENT: AN ERP STUDY IN VISUAL SEARCH

Abstract

AbstractAge-Associated memory impairment (AAMI) may be related to a decline in selective attention. In this work, the potential attentional capture by task-irrelevant stimuli was examined in older adults with AAMI compared to healthy older adults using event-related potentials (ERPs).A visual search task was employed, in which the participants had to detect the presence of a target stimulus that differed from distractors by orientation. To explore the automatic attentional capture, an irrelevant distractor stimulus defined by color was also presented without previous knowledge of the subjects. The N2pc component of ERPs, an electrophysiological indicator of the allocation of attentional resources, was analysed.The results indicated that in both groups the N2pc component was present for target stimuli but not for task-irrelevant color stimuli. In addition, the latency of N2pc for targets was significantly delayed in AAMI patients compared to controls, although no differences in the amplitude of the component were found.The delay in N2pc latency in AAMI subjects suggested they require more time than healthy seniors to shift their visuospatial attention onto the task-relevant information. However, the lack of significant differences between the groups in N2pc mean amplitude and scalp distribution suggested that the amount of attentional resources allocated to the target did not differ between older adult with and without memory impairment. The lack of N2pc component for irrelevant non-target stimuli indicated that the mechanism of top-down suppression of task-irrelevant information is preserved.Funding: Xunta de Galicia (GPC2014/082)