The Recovery Mechanism Of RTMS On Non-fluent Aphasia After Stroke: An Investigation By Rs-fMRI

Objective:Resting-state fMRI(rs-f MRI)is used to investigate the recovery mechanism of rTMS(repetitive transcranial magnetic stimulation)in the treatment of non-fluent aphasia after stroke.Materials and Method:Study 1: Based on rs-fMRI,to investigate the difference between spontaneous activities of the brain in patients with non-fluent aphasia after stroke and normal subjects.We collected 18 patients in our hospital with non-fluent aphasia after stroke from August 2016 to December 2017 according to inclusion criteria.The aphasia battery of Chinese(total language score,listening,recognizing,verbal instructions,word retelling,sentence repetition,word naming,color naming,reaction naming and column naming)and rs-fMRI examination was tested in the patients.In addition,18 normal persons were recruited for rs-fMRI examination.Finally,we Compared the Regional Homogeneity(ReHo)values between the aphasic patients and the control,and performed ReHo statistical analysis in the REST and performed an independent two-sample t-test on patients with aphasia and normal controls.Study 2: The recovery mechanism of rTMS on non-fluent aphasia after stroke: an investigation by rs-fMRI.:14 patients with non-fluent aphasia included in the first part of the study were randomly divided into rTMS(stimulate the right Broca area with low-frequency)group with 7 patients and a language training group withthe tests.The ABC?MMSEand BDAEwere performed in the two groups on the day of enrollment?after two weeks of treatment,and four weeks of treatment.rs-fMRI was performed on the day of enrollment and after four weeks of treatment.Then we record the assessment results of each group at three time points and compare them within and between groups.The ReHo was used to study the difference among brain regions of the two groups on the day of enrollment and after 4 weeks of treatment,.Paired t-tests were used for intragroup comparisons and independent two-sample t-tests were used for comparisons between groups.P<0.05 was considered statistically significant.Results:Study 1: Compared with the normal controls,the increased Regional Homogeneity(ReHo)was mainly concentrated in the right hemisphere.The specific brain areas including right side of the putamen,the right side of the cingulate gyrus,the right frontal middle frontal gyrus,and the right central frontal gyrus.The reduced ReHo is mainly concentrated in the left hemisphere,including left thalamus,inferior frontal gyrus,left lateral gyrus,left middle frontal gyrus,left central posterior gyrus.Study 2:Scores and results of the test: Comparison within groups:in the rTMS group,there were no statistically significant differences upon sentence repetition?color naming and column naming between the second week of treatment and the day of enrollment,except for the other items of the ABC.(P<0.05).And,after four weeks treatment,patients have gotten much higher scores in the test,comparing with the first two times.(P<0.05).Comparing with the day of enrollment,the language training group have showed statistically difference on total language score?listening? recognizing?verbal instructions?word retelling?word naming after the second weeks of treatment.After the four weeks treatment,There were statistically significant difference upon all the items.(P<0.05).Results about ReHo: Intragroup comparison:(1)the brain regions with increasedRegional Homogeneity(ReHo)after treatment in the rTMS group were mainly concentrated in the left hemisphere,especially in the brain area surrounding the lesion,includingleft superior border,left middle frontal gyrus,left frontal frontal gyrus,right hippocampus.(2)The pure language training treatment group was found in the brain areas with increased and decreased ReHo after treatment,including right atrium,right hippocampus,right insular lobe,right inferior triangle frontal gyrus,right frontal middle frontal gyrus,left insula,left lateral putamen,left caudate nucleus,left dorsolateral frontal gyrus.The brain area with reduced ReHo is mainly concentrated in the right hemisphere,including the right frontal gyrus,the right inferior temporal gyrus,the visual cortex,and the left straight back.Conclusion:1.Left-sided brain injury in patients with post-stroke aphasia results in decreased activity in the left hemisphere,which may be one of the mechanisms of aphasia2.Low-frequency rTMS stimulation against Broca area of the non-dominant hemisphere can inhibit the hyperexcitability of the non-dominant cerebral hemisphere cerebral cortex,relieving its inhibition of the left hemisphere and promoting the reconstruction of the dominant hemisphere's language network,and ultimately proceeding the recovery of language function in those patients.3.The recovery of linguisticfunction in patients with aphasia may involve the network reconstruction or functional compensation of bilateral cerebral hemispheres,but the effect on network repair and reconstruction around the lesions is more important and prominent.4.Combining low-frequency rTMS treatmentwith language training,the treatment of patients with non-fluent aphasia after stroke can be better.