Rehabilitation Of Aphasia And Related Research Based On Transcranial Magnetic Stimulation

As a brain function unique to human being,language function is a basic tool for people to adapt to social environment and to realize their value of life.However,human language is fragile and mysterious,and its mechanism is still largely unknown.It is thus important in brain science to explore and study the basic principles of brain language function and its rehabilitation.Thanks to the development of functional neuroimaging technology,neurolinguistic scientists can now study the language function with non-invasive neuroimaging techniques in healthy subjects.However,these techniques are generally used to study the correlation between specific brain functions and regions,and lacks the ability to explore the causal relationship between brain regions and functions.This study is to explore the language-related brain regions of aphasia patient and normal adults based on Transcranial Magnetic Stimulation(TMS)-a technique that modulates normal neural activity in specific brain regions and affects their functional expression.This study started with a patient with aphasia after left hemisphere stroke.A language rehabilitation training was designed and implemented according to the brain damage and aphasia symptoms of the patient.Secondly,a language cognition experiment based on TMS was designed to explore the function of some damaged brain regions and language rehabilitation in this patient.The language rehabilitation training mainly contains Reading Task of Chinese characters,Picture Naming Task and Number Naming Task,together with a TMS section.Three brain areas including left anterior/posterior Temporoparietal Cortex,inferior Parietal Lobule and their homologous brain regions will be stimulated in the repetitive TMS sections,to activate potential brain plasticity or compensation.The high frequency of rTMS on the left brain hemisphere was used to facilitate the neural activity in lesion area and its surrounding regions,while the low-frequency,targeting on the right brain region,was use to inhibit the neural activity in the right healthy brain region that may be over-activated,and to regulate the balance of activation in the left/right brain regions through the corpus callosum.The data showed that after the rehabilitation training,the patients' ability of reading Chinese characters,naming pictures and numbers was restored to a certain extent,indicating promoting effect on language function of TMS neural regulation.Meanwhile,the patient's subjective feeling also affirmed the rehabilitation effect.In addition,based on the rehabilitation training of the patient,this study took the patient and normal adults as subjects,and used TMS to explore the causal relationship between language brain regions(the left inferior frontal and temporoparietal cortices)and language processes(Chinese phonological and semantic processing).This exploratory experiment used a 2-by-2 two-factor design involving two brain regions(the inferior frontal and temporoparietal cortex)and two language tasks(phonological and semantic tasks),requiring the patient to complete the language task before and after iTBS stimulation targeted brain regions,and recording the response time and accuracy of the subjects.The TMS method adopted in this experiment is the high-frequency intermittent theta burst stimulation(iTBS),which can achieve the same effect as rTMS,though it required weaker stimulus intensity.iTBS is very suitable for the inferior frontal gyrus,which is more sensitive to TMS Stimulation.It was found that compared with normal adults,the accuracy of patients in completing the language task was significantly improved after TMS stimulation in Broca area and Supramarginal Gyrus(SMG)(which is located in the temporoparietal cortex),while no same effect was found in normal subjects.It was also found that stimulating Broca's region significantly improved the accuracy of speech task in patients,which suggest that Broca's area may play a compensatory role in the case of severe brain damage of SMG.The results were also verified and complemented in rehabilitation training for aphasia,which confirmed the important role of TMS in neuromodulation and reflected its effectiveness and feasibility in studying brain language function and language rehabilitation.