Visual search in Alzheimer's disease and amnestic mild cognitive impairment: An eye-tracking study.

Abstract

Visual search impairment is a potential cognitive marker for Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI). The aim of this study is to compare eye movements during visual tracking in AD and aMCI patients versus healthy controls (HCs). A prospective cohort study included 32 AD and 37 aMCI patients, and 33 HCs. Each participant was asked to look at the target object in a visual stimulus containing one target and eight distractors, and eye movements were recorded with EyeLink 1000 Plus. AD patients had fewer fixations and shorter target fixation duration than aMCI patients and HCs. Fixation durations were also shorter in aMCI patients compared to HCs. Also, AD patients were more fixated on distractors than HCs. Our findings revealed that visual search is impaired in the early stages of AD and even aMCI, highlighting the importance of addressing visual processes in the Alzheimer's continuum. AD patients looked to distractors more and longer than the target compared to aMCI patients and older healthy individuals. aMCI patients had an impaired visual search pattern compared to healthy controls, just like patients with AD. The visual search task differentiated AD and aMCI patients from healthy individuals without dementia.