Voxel-based Morphology To Investigate The Correlation Between Loneliness And Gray Matter Volume In Patients With Mild Cognitive Impairment

Objective:In order to explore the possible mechanism between loneliness and mild cognitive impairment(MCI),the correlation between different levels of loneliness and the volume of gray matter in brain regions was analyzed by methods of voxel-based morphology(VBM)in cognitively normal peolple and MCI patients.Methods:A cross-sectional study design was used in this study.The general demographic data of524 volunteers in Fuzhou were collected,including age,sex,years of education,living conditions,and marital status.In addition,University of California at Los Angeles-Loneliness Scale(UCLA-LS),Montreal Cognitive Assessment(Mo CA),Ascertain Dementia-8(AD8),Instrumental Activities of Daily Living scale(IADLs)and Geriatric Depression Scale-15(GDS-15)were used to evaluate 524 subjects.A total of 133 eligibe subjects were included,including 70 cognitively normal subjects and 63 MCI patients.Subsequently,according to the average value of UCLA-LS,the cognitively normal group and MCI group were divided into cognitively normal-low loneliness group,cognitively normal-high loneliness group,MCI-low loneliness group,and MCI-high loneliness group.Siemens Prisma 3T magnetic resonance imaging(MRI)scans of the subjects were performed to collect T1 structural image data.In Matlab 2019 platform,CAT 12 and SPM 12 software were used to preprocess MR data,and two-way ANOVA was used to observe the brain regions with significant interaction between the groups by VBM method.Then,two independent samples t-test was used to compare the differences in gray matter structure between cognitively normal-low loneliness group and cognitively normal-high loneliness group,as well as between MCI-low loneliness group and MCI-high loneliness group.A threshold of voxelwise P<0.001 and P<0.05 family-wise error(FWE)corrected at cluster level was applied for all the analyses.Then,the brain regions with significant differences between groups were taken as regions of interest(ROI).The gray matter density of each subject’s corresponding ROI was extracted by DPABI 5 software,and the correlation between UCLA-LS score and ROI gray matter volume was analyzed by partial correlation analysis.Results:1 There were no significant differences in age,sex,residence status,marital status,chronic medical history,BMI,TIV and IADLS score among the four groups(P>0.05),but there were significant differences in years of education,MOCA score,GDS-15 score,and UCLA-LS score(P<0.001).2 There were significant negative interactions in the right medial frontal gyrus,paracentral lobule and left paracentral lobule in the four groups.Separate effect analysis showed that in the cognitively normal group,the gray matter volume in the high loneliness group was significantly larger than that in the low loneliness group,and in the MCI group,gray matter volume in the high loneliness group was significantly smaller than that in the lowloneliness group;Partial correlation analysis showed that after controlling for age,sex,years of education,GDS-15 score,MOCA score,and TIV,the gray matter volumes in the right medial frontal gyrus,paracentral lobule,and left paracentral lobule were significantly positively correlated with UCLA-LS score in the cognitively normal group(r=0.426,P=0.001),and negatively correlated with UCLA-LS score in the MCI group(r=-0.407,P=0.002).3 The comparison between the cognitively normal-low loneliness group and the cognitively normal-high loneliness group showed that the gray matter volume in left cerebellar posterior lobe,cerebellar crus1,cerebellar 6,right cerebellar posterior lobe,cerebellar crus1,cerebellar 6 and lingual gyrus of the cognitively normal-low loneliness group was significantly higher than that of the cognitively normal-high loneliness group,and the gray matter volume in right paracentral lobule and medial frontal gyrus was significantly lower than that in the cognitively normal-high loneliness group.Partial correlation analysis showed that after controlling for age,sex,years of education,GDS-15 score,MOCA score and TIV,there was no significant correlation between the gray matter volume of the above brain regions and UCLA-LS score in the cognitive normal-low loneliness group(P>0.05),and in the cognitive normal-high loneliness group,only the gray matter volume of right posterior cerebellar lobe,cerebellar Crus1 and lingual gyrus had significant negative correlation with UCLA-LS score(r=-0.456,P=0.017).4 The comparison between the MCI-low loneliness group and the MCI-high loneliness group showed that in left cerebellar 8,cerebellar tonsil,cerebellar posterior lobe,hippocampus and parhippocampal gyrus of MCI-low loneliness group was significantly lower than that of the cognitive normal-high loneliness group,and the gray matter volume in left lingual gyrus and fusiform gyrus was significantly higher than that in the MCI-high loneliness group Partial correlation analysis showed that after controlling for age,sex,years of education,GDS-15 score,MOCA score and TIV,there was no significant correlation between the gray matter volume of the above brain regions and UCLA-LS score in MCI-low loneliness group(P>0.05),and in the MCI-high loneliness group,the gray matter volume of left hippocampus and the parhippocampal gyrus(r=-0.540,P=0.004),as well as the left lingual gyrus and the fusiform gyrus had significant negative correlation with UCLA-LS score(r=-0.443,P=0.023).Conclusions:1 In the cognitively normal group,the gray matter volume of the right medial frontal lobe and bilateral paracentral lobes was significantly positively correlated with UCLA-LS score,while in the MCI group,the gray matter volume of the right medial frontal lobe and bilateral paracentral lobes was significantly negatively correlated with UCLA-LS score.2 Loneliness was associated with gray matter volume in the structure of brain regions in patients with MCI.In the MCI-high loneliness group,the gray matter volume of left hippocampus and the parhippocampal gyrus,as well as the left lingual gyrus and the fusiform gyrus had significant negative correlation with UCLA-LS score.