Relationship Between DLPFC Functional Connectivity And Cognitive-walking Ability In Patients With Cognitive Impairment

Objective:In this study,we used functional imaging to study the characteristic changes of functional connectivity between dorsolateral prefrontal cortex(DLPFC)and motor control related brain regions in the elderly with subjective cognitive impairment(SCD)and mild cognitive impairment(MCI),and to explore the relationship between DLPFC and gait parameters in cognitive assessment and dual task performance.Method:According to the grouping criteria,115 elderly people were divided into MCI group(n = 35),SCD group(n = 43)and normal cognition group(n = 37).Neuropsychological assessment,resting state f MRI scanning and dual task gait analysis were performed in all the elderly.Based on the MATLAB platform,we analyzed the MRI data by using the software restplus and dpabi,and obtained the functional connectivity(FC)values between the left DLPFC with the medial part of the bilateral superior frontal gyrus,the bilateral precuneus lobe and the bilateral middle temporal gyrus.Then a multiple linear regression model was established to analyze the relationship between FC value and AVLT-N5,TMT B-A,AFT,DT speed and DTC.Result:There was no significant difference in age,sex ratio,basic disease and other basic data among MCI group,SCD group and NC group(P > 0.05).The results of neuropsychological tests between MCI,SCD and NCgroups were significantly different(P < 0.05).Along with the development of cognitive impairment,the global cognitive,memory,language ability and executive function of the elderly decreased significantly,and the degree of depression increased significantly with the decline of cognitive function(P < 0.05).Compared with SCD group,there were significant differences in FC of MCI patients between left DLPFC and bilateral middle frontal gyrus,left middle temporal gyrus,left anterior cingulate gyrus and right medial superior frontal gyrus(P < 0.05);there were significant differences in FC of MCI patients between right DLPFC and bilateral superior frontal gyrus,middle frontal gyrus,triangle of inferior frontal gyrus and right medial superior frontal gyrus(P <0.05).Compared with NC group,there were significant differences in FC of MCI patients between left DLPFC and bilateral superior frontal gyrus,bilateral middle frontal gyrus,bilateral medial superior frontal gyrus and left middle temporal gyrus(P < 0.05);there were significant differences in FC of MCI patients between right DLPFC and right medial superior frontal gyrus,right precuneus and bilateral middle temporal gyrus(P < 0.05).The linear regression model was established by TMT B-A,AFT,DTC and age.The results showed that the higher the DTC,the stronger the FC between the left medial superior frontal gyrus and the left DLPFC(β [95% CI]:0.293 [0.146,1.717],P = 0.021),and the stronger the FC between the right medial superior frontal gyrus and the left DLPFC(β [95% CI]: 0.275 [0.058,1.499],P =0.035).The larger the TMT B-A score and the higher the DTC,the stronger the FC between the left precuneus lobe and the left DLPFC(β [95% CI]: 0.338 [0.001,0.004],P = 0.006;0.243 [0.001,0.079],P = 0.043).The older the TMT B-A was and the younger the patient is,the stronger the FC between the right precuneus lobe and the left DLPFC is(β [95% CI]: 0.379 [0.001,0.004],P = 0.035;-0.272 [-1.439,-0.098],P = 0.025).Linear regression model was established by TMT B-A,AVLT-N5,DTC and dual task walking speed.The higher the score of delayed recall(N5)and the slower the dual task walking speed,the stronger the FC between left middle temporal gyrus and left DLPFC(β [95% CI]: 0.334 [0.014,0.086],P = 0.007;-0.324 [-1.182,-0.090],P = 0.023).The larger the TMT B-A and the faster the dual task walking speed,the stronger the FC between the right middle temporal gyrus and the left DLPFC(β [95% CI]: 0.239 [0,0.003],P = 0.049;0.313 [0.005,0.030],P = 0.007).Conclusion : Compared with SCD and healthy elderly,the functional connections between DLPFC and frontal,temporal and parietal lobe of MCI patients were increased.The functional connectivity of left DLPFC was affected by memory function,executive function,dual task consumption,dual task walking speed and age.