Study On The Brain Function In Poststroke Patients With Non-fluent Aphasia Of Different Severity By Rs-fMRI

Objective:Using resting-state functional magnetic resonance imaging(rs-f MRI)to study the brain function in post-stroke patients with non-fluent post-stroke aphasia(PSA)of different severity in order to provide an imaging basis for the brain mechanisms of PSA and the objective assessment and precise rehabilitation of PSA.Materials and methods:Study 1: Differential study of dALFF in patients with non-fluent aphasia of different severity.18 mild to moderate non-fluent PSA inpatients and 18 severe non-fluent PSA inpatients from June 2016 to December 2021 were enrolled according to Chinese version of the western aphasia battery(WAB)test and inclusion and exclusion criteria,20 normal persons were recruited as well.All participants underwent rs-f MRI examination.The dALFF values of the three groups of participants were calculated and analyzed by one-way ANOVA.We also performed the Spearman correlation analysis of dALFF values of different brain areas and the patients’ WAB linguistic scores and AQ score to observe correlation between characteristics of spontaneous activity of three groups and verbal functions and AQ scores.Study 2: Differential study of dFC in patients with non-fluent aphasia of different severity.The language-related brain areas in study 1 were selected as ROI to calculate the dFC values of mild to moderate PSA group and severe PSA group,and separately performed an independent two-sample t-test on normal people and mild to moderate and severe PSA group to analysis the differential characteristics of the overall functional connectivity network of the brain in PSA patients.Results:Study 1: Results of the analysis of dALFF values in differential brain areas and their correlations with WAB linguistic scores and AQ score in three groups.1.Comparison between mild to moderate PSA group and normal group:Compared to normal group,mild to moderate PSA group exhibited increased dALFF values in bilateral hemispheres: left anterior wedge,left medial epicentral,left cerebellar foot area 1,right paragonal central lobule,right wedge anterior lobe,right cingulate posterior part,right middle frontal ileoorbitia,right side complementary active area,right corner gyrus;brain regions with lower dALFF values are all located in the left hemisphere: left superior margin gyrus,left anterior central gyrus,left paracentral lobule.Left central anterior gyrus is the only brain region that significantly positively correlated with the WAB listening,repetition,naming,reading and AQ score in mild to moderate PSA group.(p<0.05)2.Comparison between severe PSA group and normal group:Compared to normal group,severe PSA group exhibited increased dALFF values in right hemispheres: right wedge anterior leaf,right frontal midriff,right wedge,right side of the dorsal lateral frontal gyrus,right occipital midge,right middle occipital gyrus;brain regions with lower dALFF values are all located in the left hemisphere: cerebral gyrus under the left inferior parietal bone without the upper and angular gyrus,the left horn gyrus,the left complementary active area,the left rolando shell cover,the left central anterior gyrus,and the left midfrontal gyrus.Left middle frontal gyrus is the only brain region that significantly positively correlated with the WAB repetition,naming,reading and AQ score in severe PSA group.(p<0.05)3.Comparison between severe PSA group and mild to moderate PSA group:Compared to mild to moderate PSA group,there is no increased dALFF values brain region in severe PSA group;brain regions with lower dALFF values is located in left angular gyrus.There is no correlation between dALFF value and WAB linguistic scores and AQ score.(p>0.05)Study 2: Results of the dFC difference study in patients with non-fluent aphasia of different severity.1.Differential brain areas of dFC values in the mild to moderate PSA group when left central anterior gyrus selected as ROI:Brain areas with enhanced dFC values in the mild to moderate PSA group were predominantly located in the left hemisphere compared to the normal group: left fusiform gyrus,left central posterior gyrus,left Rolando shell cap,left superior temporal epicenteral pole,left margin upper gyrus,left cerebellar foot area 1,left cerebellum 4,5 area,left middle temporal gyrus,right temporal epicenteral pole;the brain areas with reduced dFC are located in the left hemisphere: the insula of the left inferior frontal gyrus,and the triangle of the left inferior frontal gyrus.2.Differential brain areas of dFC values in the severe PSA group when left middle frontal gyrus selected as ROI:Brain areas with enhanced dFC values in the severe PSA group were located in the right hemisphere compared to the normal group: right inferior frontal gyrus orbital region;the brain regions of the brain with reduced dFC are located in the left hemisphere: the left parietal bone below the cerebral gyrus except for the upper and angular gyrus,and the left inferior frontal gyrus cap.Conclusion:1.Non-fluent PSA patients with left hemisphere lesions have reduced spontaneous activities in the left precentral gyrus(in patients with mild to moderate PSA)and left middle frontal gyrus(in patients with severe PSA)and these reduced spontaneous activities are associated with several language functions,which may be involved in the occurrence mechanism of PSA.2.Patients with non-fluent PSA of different severity have diminished functional connectivities of the language network within left hemisphere,presumably related to the mechanism of PSA development.The enhanced functional connectivities in patients with mild to moderate PSA is predominantly intra-hemispheric and in patients with severe PSA is predominantly inter-hemispheric,which indicates the recovery of language functions in PSA patients may involve in both hemispheres..The mild to moderate PSA group is dominated by the repair and reconstruction of function in the brain areas surrounding the left-sided lesion,while severe PSA group relies mainly on right hemisphere function for compensation due to severe damage to the left hemisphere.3.The dALFF values of the left precentral gyrus and the left middle frontal gyrus are positively correlated with AQ score,and may be used as one of the reference indicators to assess the severity of non-fluent PSA.