Abstract: Objective To investigate the effect of repetitive transcranial magnetic stimulation (rTMS) on the brain functional reorganization of aphasia after stroke, with functional magnetic resonance imaging (fMRI).Methods From January, 2017 to February, 2018, six eligible stroke patients with aphasia were recruited in experimental group, and nine age-gender matched healthy adults were recruited in healthy control group. Subjects in both groups received task-fMRI, and the experimental group was assessed with Chinese version of Western Aphasia Battery (WAB) examination before and after rTMS treatment. Four patients underwent rTMS at the right inferior frontal gyri pars triangularis marked by neuro-navigation-guided system, 1 Hz, five times per week for two weeks. The fMRI data were processed by SPM 12. The differences of brain activation and voxel changes between two groups were compared. The fMRI data including the differences in brain activation, voxel volume and activation voxel indices (AVI) and WAB scores were analyzed before and after rTMS.Results The cerebral hemisphere activation in the experimental group was higher than that of the healthy control group,including the regions of interest (ROI) such as bilateral supplementary motor area and middle frontal gyrus, and the non-ROI (n-ROI) such as left praecuneus, left postcentral gyrus, right hippocampus, right paracingulate cortex, etc., while the activation reduced in the areas of left pars triangularis and n-ROI such as left calcarine fissure cortex, left gyrus lingualis, the right anterior cingulate and the paracingulate cortex. Cases 1 and 2 had shorter course of disease, smaller lesion volume, and activation increased in bilateral cerebral hemispheres before treatment. AVI showed that their hemispheric dominance was right, and activation reduced in bilateral cerebral hemisphere after treatment, but the high-efficiency language function area of ROI, such as the left pars triangularis, turned from inactive to active, and the hemispheric dominance lateralized from right to left, with the improvement of language function. For the case 3 and case 4, the disease courses were longer, the lesions sizes were larger, and both cerebral hemisphere activations were reduced before treatment. AVI showed that the hemispheric dominance of case 3 was right and was left in case 4. After treatment, bilateral cerebral hemispheres were activated more than before, and the hemispheric dominance of language function was in the right hemisphere; the left middle frontal gyrus and right middle temporal gyrus were activated from no activation before treatment in case 3. The activation of the supplemental motor area on the right side was increased. In case 4, there was no activation in ROI before treatment. After treatment, the bilateral supplementary motor area, right pars opercularis, and the right middle temporal gyrus were activated.Conclusion Low-frequency rTMS could improve the language function by optimizing bilateral cerebral hemisphere brain areas related with language function in patients with aphasia after stroke.

Key words: stroke, aphasia, functional magnetic resonance imaging, transcranial magnetic stimulation, functional reorganization