Memory decline is associated with an underlying reduction in visual exploration and sampling, according to a study published today in PNAS.
Jordana S. Wynn, Ph.D., of the University of Victoria, Canada, and colleagues enrolled 106 volunteers spanning five groups of decreasing cognitive strength:
- 38 young adults ages 18 to 35
- 37 cognitively healthy older adults ages 60 to 85, scoring 26 or higher on the Montreal Cognitive Assessment (MoCA)
- 12 older adults ages 60 to 85 at risk of cognitive decline, scoring lower than 26 on the MoCA
- 15 adults ages 46 to 89 with diagnosed mild cognitive impairment
- Four adults (ages 30, 57, 64, and 66) with amnesia
All participants had normal or corrected vision and hearing and no history of psychiatric illness.
Participants completed two separate tests of naturalistic vision (though not everyone completed both tests). In the first, they viewed 120 unique images (on screen for five seconds) while their eye movements were carefully tracked. The second task was similar except that half the images were presented three times.
The researchers found that for both tasks, gaze patterns followed a linear trend across groups wherein young adults showed the most visual dispersion and the amnesic adults showed the least. In the first task, adults with greater cognitive impairment tended to look at the same areas of the screen regardless of the image. In the second task, cognitively healthy adults gazed at new parts of an image when it repeated, whereas those with decreased cognition tended to focus on the same image features when it repeated.
“[E]ye movements can reveal population differences in memory function, even in the absence of explicit task demands,” Wynn and colleagues wrote. “Our results provide compelling evidence that naturalistic gaze patterns can serve as a sensitive marker of cognitive decline.”
For related information, see the Psychiatric News article “Visual Diagnostics Become More Accessible.”
(Image: Getty Images/iStock/pixdeluxe)
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