The Study Of Facial Emotion Recognition And Visual Processing Mechanism In Patients With Alzheimer’s Disease And Mild Cognitive Impairment

Background:Facial emotion is considered one of the most important sources of non-verbal information in human social interaction,containing important information and capable of conveying a person’s emotional state.Recognizing facial emotions is an important social skill and an advanced cognitive function.Previous studies have rarely described the exploration of facial emotion recognition（FER）ability in patients with mild cognitive impairment（MCI）.In contrast,a relatively large number of studies have been conducted on the FER capacity of patients with Alzheimer’s disease（AD）,and the results have been mixed.Eyes tracking（ET）technology is a sensitive,low-cost,non-invasive research method of visual processing mechanism.Therefore,the use of ET technology to study the visual mechanism of facial emotion processing in patients with cognitive impairment has great advantages.Objective:1.To explore whether there is facial emotion recognition disorder in AD and MCI patients;2.To explain the visual processing mechanism of emotional faces processing disorder in AD and MCI patients by ET technology.Method:26 AD patients,24 MCI patients,and 21 healthy controls（HC）were enrolled in this study.Due to human interference and factors affecting calibration due to excessive eye blinking,11 participants in the large sample could not reliably perform FER testing and visual scanning tasks.Therefore,this study finally included 20 AD patients,20 MCI patients,and 20 healthy controls.The three groups performed cognitive psychological assessment and FER test on all the above subjects to compare the cognitive and facial emotion recognition results.All the above subjects were subjected to the emotional face visual scanning task using ET technology to obtain eye movement data.The visual processing results of the facial emotions of the three groups of subjects were compared.Results:Our results showed that AD patients’ total FER correct rate was significantly lower than the HC group’s（p<0.05）.Compared with MCI,although the total FER correct rate of AD patients was lower than that of MCI,the difference was not statistically significant（p> 0.05）.There was no significant difference in the correct rate of FER between MCI patients and HC group（p>0.05）.The results of the eye movement index showed that the AD group,MCI group and HC group had significant differences in fixation time and fixation times in the eye area（p<0.05）.Post-hoc analysis showed that the fixation time and the number of fixations in the eye area of AD patients were lower than those of the normal control group.Spearman correlation analysis showed that the total FER correct rate in the AD and MCI groups was significantly positively correlated with neuropsychological test results（P<0.05）.In addition,it was found that the total FER correct rate of AD patients was correlated with the number of fixations in the eye area（r=0.450,P=0.046）.Conclusions:This study showed that the correct rate of FER in AD patients was reduced and showed a gradient effect with MCI and HC.At the same time,we have not found a statistically significant difference in the correct rate of FER between AD and MCI,suggesting that when the early cognitive function of MCI patients is relatively preserved,facial emotion recognition has already been damaged reaching a similar level to AD.In addition,AD patients have facial emotion visual processing disorder,which is manifested as a decrease in the time and number of eye fixations,which may be the reason for the decreased FER ability of AD.