Visual search in patients with Alzheimer’s disease and mild cognitive impairment: Kitchen scanning task

Abstract

Background

We aimed to evaluate the visual scanning patterns of patients with Alzheimer’s Disease (AD) and amnestic mild cognitive impairment (aMCI).

Method

29 AD patients (mean age 72,5±7.9 years), 34 aMCI patients (mean age 70,6±6,7 years), and 32 healthy control (HCs) (mean age 68,5±6,2 years) were given neuropsychological tests (NT) with five domains and eye movements were recorded when doing a kitchen scanning task. Firstly, participants were asked to find a single object in the three kitchen pictures shown and secondly to prepare scrambled eggs, Turkish coffee and breakfast. The first 3 pictures are 6000 ms, the other 3 pictures are shown for 10000 ms. The kitchen materials required for the given tasks were identified as an area of interest. Fixation duration, fixation count, first fixation duration, and saccade count were recorded with EyeLink 1000 Plus video eye tracker.

Result

There was no significant difference in age and education between aMCI, AD patients, and HCs (p<0,05). In the first task, AD patients were a statistically decreased in fixation duration than aMCI and HC groups (p = 0,001), and in saccade count compared to HC’s (p = 0,031). Also, patients with AD were a statistically increased number of fixations in the out of interest area compared to aMCI and HC groups (p = 0,009). In the second task, AD patients had significantly decreased fixation duration compared to aMCI and HC groups (p = 0,006), and in first fixation duration than HC’s (p = 0,02). In addition, AD patients had significantly decreased number of saccades in the out of interest area compared to HC’s (p = 0,048). All measured saccadic parameters were weakly correlated with cognitive test scores (r = 0,2‐0,4).

Conclusion

This study showed that patients with Alzheimer’s disease performed fewer saccades when visual scanning and scanned the visual field less with a shorter fixation duration compared to aMCI and HC’s. This may be related to the deterioration of visual memory and visual attention in AD patients.