A Japanese research group has proposed that failure to recognize or memorize human faces in the short term could be early stage of dementia. The elderly with mild cognitive impairment (MCI) suffer from weakened ability to recognize faces when compared to healthy elderly people. When trying to memorize, their gaze is also different, suggest Japanese researchers.
Alzheimer’s disease, the most common type of dementia, should be detected in its early stages to halt its progression into a more serious form of the disease. MCI, a preliminary stage of Alzheimer’s, is detected with weak cognitive functions, such as poor memory or inability to think though these traits do not affect daily life.
MRI scans of brain imaging show that areas for memory and visually processing human faces in people are structurally and functionally transformed during this stage.
Researchers 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 and then, after a short delay, select a memorized image from a set new of images. The researchers also recorded subject gaze trends during the image memorization process.
Their experiments revealed that the memorization performance of MCI patients was lower for facial images than for house images. However they found no performance difference in normal subjects.
While memorizing, MCI patient’s gaze concentration on the eyes of an image decreased but the time spent looking at the mouth increased. They had reduced short-term memorization ability and a different gaze pattern for faces when compared to normal people, said researchers.
“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.”
This research was published online in the journal Scientific Reports.