AsianScientist (Dec. 4, 2017) – A Japanese research group has revealed that elderly people with mild cognitive impairment (MCI) have a particularly weakened ability to memorize human faces in the short term when compared to healthy elderly people. Their findings are reported in Scientific Reports.
Alzheimer’s disease (AD) is considered to be the most common type of dementia, and early detection of preliminary stages is important to halt its progression into a more serious form of the disease. MCI, which is thought to be a preliminary stage of AD, is a state in which cognitive functions, such as memory or thinking ability, decrease at a level that do not affect daily life.
Brain imaging studies show that areas of the brain involved in memory and visual processing of human faces is functionally transformed in people with MCI. To investigate these specific and yet unstudied areas, a research group from Kumamoto University in Japan conducted comparative experiments with normal elderly subjects and MCI patients (18 each) using a delayed-matching task with face and house stimuli in independent blocks.
In each block, they asked subjects to remember a single image. Then, after a short delay, the subjects were asked to select a memorized image from a set new of images. The researchers also recorded trends in the subjects’ gaze during the image memorization process.
Their experiments revealed that the memorization performance of MCI patients was lower for facial images than for house images. In contrast, normal patients could memorize face and house images equally well. The researchers also observed that, during the memorization process, MCI patients tended to gaze less at the eyes of an image but spent a longer time looking at the mouth compared to normal subjects. In essence, 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 of Kumamoto University who is an author of the study. “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.”
Source: Kumamoto University; Photo: Shutterstock.
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