Elderly people with mild cognitive impairment (MCI) have a much harder time remembering human faces in the short term compared to healthy elderly people, according to a new study by researchers at Kumamoto University in Japan. The findings also show that MCI patients appear to use a different type of gazing behavior while trying to memorize a face.
Alzheimer’s disease is considered the most common type of dementia, and early detection is key to slowing its progression into a more serious form of the disease. MCI, which can sometimes be a preliminary stage of Alzheimer’s, is characterized by impaired levels of memory and thinking but not at a level severe enough to debilitate a person in daily life.
The researchers believe the new findings may help lead to the early detection of dementia.
Brain imaging studies show that brain regions associated with memory and the visual processing of human faces in MCI patients are structurally and functionally different. Researchers conducted comparative experiments between 18 MCI patients and 18 normal elderly participants using a delayed-matching task with face and house stimuli.
In each segment, the researchers asked subjects to remember a single image and then, after a short delay, to select a memorized image from a set of new images. The researchers also recorded participant gaze trends during the image memorization process.
The findings show that the memorization performance of MCI patients was worse for facial images than for house images, while no performance difference was found among normal subjects.
The researchers also found that, during the memorization process, MCI patients spent less time gazing at the eyes and more time looking at the mouth compared to healthy subjects. Overall, MCI patients had reduced short-term memorization ability and a different gaze pattern for faces when compared to normal people.
“Looking at the eyes is important for remembering the entirety of the face,” said Emeritus Professor Kaoru Sekiyama. “MCI patients probably have an abnormality in the cognitive processing of faces due to the deterioration of brain function. It is possible that the distributed gaze pattern is compensation for this decreased function. We hope to shed some light on this possibility in future work.”
The new findings are published online in the journal Scientific Reports.
Source: Kumamoto University