Brain Activity Alterations In Parkinson’s Disease With Cognitive Impairment Based On Resting State Functional Magnetic Resonance Imaging Study

ObjectiveParkinson’s disease with cognitive impairment(PD-CI)is a prevalent non-motor symptom in PD and PD with mild cognitive impairment(PD-MCI)develops a high risk of Parkinson’s disease dementia(PD).Therefore,early screening and early intervention of PD-CI are important to delay the progression of PDD.However,the pathogenesis of PD-CI remains unclear.A growing number of studies have sought to establish neuroimaging markers to detect changes in brain function in patients with PD-CI through resting functional magnetic resonance imaging(rs-f MRI).The change of brain function activity homogeneity can be realized by the regional homogeneity(ReHo)analysis method of rs-f MRI proposed by Zang et al Chinese scholars.ReHo can detect the spontaneous activity of brain neurons and then reflect the increase or decrease of brain activity consistency.The purpose of this study was to analyze the characteristics of brain function activity in patients with PD with/without cognitive impairment by the method of ReHo based on the rs-f MRI.The above results combined with the clinical scale and neuropsychological evaluation contributed to further improve the accuracy of clinical early diagnosis of PD-CI,which could provide important clues for early diagnosis,disease monitoring and pathogenesis of PD.MethodsThis study collected 36 primary PD patients in the neurology department of Hebei General Hospital from May 2018 to December 2019.During the same period,20 healthy controls(HCs)with matched age,sex,education,and Mo CA score > 26,were recruited from the Hebei General Hospital medical examination center.This study used the Hamilton Depression Assessment Scale(HAMD)to exclude severe depressive patients,and the Montreal Cognitive Assessment Scale(Mo CA)scores divided PD patients into two PD subgroups: 20 patients with PD-CI and 16 patients with Parkinson’s disease with normal cognitive function(PD-NC).The magnetic resonance was used to collect head data of all subjects in the resting state in this study,and related data processing software was used for image post-processing.Data were statistically analyzed using the Statistical Package for the Social Sciences(SPSS)26.0.Analyses of single-sample t test,covariance(ANCOVA),two-sample t test were performed using the data processing & analysis of brain imaging(DPABI)to compare the differences in ReHo values among three groups,with sex,age,education,gray matter volume,and average head motion parameters as covariates.The gaussian random field(GRF)theory was used for cluster-level multiple comparison correction in single-sample t test and ANCOVA(voxel P < 0.0005,cluster P < 0.025 and a minimum cluster size of 22 voxels),and the brain regions with a statistical difference were used as the mask of the ANCOVA post hoc t test.Post-hoc comparisons were analyzed using the two-sample t test,and multiple comparison correction was carried out using the GRF theory.Voxel P < 0.0005 and cluster P < 0.025 were set(a minimum cluster size of 13 voxels)to indicate statistical significance.The ReHo values of the two major PD subtypes were extracted from the data,and the correlation analysis between the z values and the Mo CA scores was conducted using SPSS26.0.A P value < 0.01 was set to indicate statistical significance.Results1.Demography and clinical dataThis study collected a total of 56 subjects in this study,including 20PD-CI patients and 16 PD-NC patients.2 PD-CI patients were removedbecause of excessive head movement(head movement translation > 2 mm or rotational movement > 2°).Therefore,18 PD-CI(10 male and 8 female),whose age distribution between 57 and 78 and Mo CA scores between 12 and 25;16 PD-NC(7 male and 9 female),whose age distribution between54 and 67 and Mo CA scores between 26 and 29;20 HC(12 male and 8female),whose age distribution between 48 and 71 and Mo CA scores between 26 and 29 were recruited.All subjects were right-handed.No statistically significant differences were found in sex and education among the three groups.However,age and Mo CA scores exhibited significant differences in the comparison of PD-CI versus PD-NC,and PD-CI versus HCs,showing that the patients in the PD-CI group had higher age(P = 0.001)and lower Mo CA scores(P = 0.000)compared with patients in the other two groups.No significant differences were observed between the PD-CI and PD-NC groups in terms of disease duration,UPDRS III,or H-Y score(P > 0.05).2.Comparison of ReHo results among PD-CI,PD-NC and HC groupsANCOVA revealed that the ReHo values among the PD-MCI,PD-NC,and HC groups were significantly different in the following regions: the left posterior cingulate,left superior temporal gyrus,right superior medial frontal gyrus,left triangular inferior frontal gyrus,right opercular inferior frontal gyrus,left precentral gyrus,right supplementary motor area,and left inferior parietal lobe.The ReHo value decreased in the left calcarine,left lingual gyrus,right supplementary motor area,left thalamus,left middle temporal gyrus,and right lingual gyrus,but increased in the left fusiform gyrus,in the PD-CI group compared with the HC group.The ReHo value decreased in the left inferior parietal lobe,right cerebellum＿6,right lingual gyrus,right postcentral gyrus,and right inferior temporal gyrus,but increased in the left inferior temporal gyrus and left orbital inferior frontal gyrus,in the PD-NC group compared with the HCgroup.The ReHo value decreased in the left middle frontal gyrus,right opercular inferior frontal gyrus,left inferior temporal gyrus,left orbital inferior frontal gyrus,left triangular inferior frontal gyrus,left precuneus,and right middle frontal gyrus decreased,but increased in the left precentral gyrus and left fusiform gyrus,in the PD-CI group compared with the PD-NC group.3.Analysis of correlation between ReHo value and Mo CA scores in different brain regions of the PD subgroup.The ReHo value in the left middle frontal gyrus,right opercular inferior frontal gyrus,left inferior temporal gyrus,left orbital inferior frontal gyrus,left triangular inferior frontal gyrus,left precuneus,and right middle frontal gyrus correlated positively with Mo CA scores;the correlation coefficient was 0.691,0.751,0.545,0.582,0.668,0.689,and0.709,respectively.The ReHo value in the left precentral gyrus and left fusiform gyrus negatively correlated with Mo CA scores;the correlation coefficient was-0.757 and-0.776,respectively.Conclusions1.The ReHo value of the default mode network(DMN)is closely related to PD cognitive function.The posterior DMN activity decreased before symptoms of cognitive decline appeared in patients with PD,and the anterior DMN activity increased to maintain general cognition.2.The disorder of visual conduction pathway is involved in cognitive impairment in patients with PD,and the ReHo value of the left fusiform gyrus is increased,indicating that such patients can recruit cognitive resources by improving the efficiency of visual information transmission.3.The information delivery efficiency of cortex-thalamus-cerebellum circuit played an important role in cognitive decline in PD patients.