Effects Of Corticospinal Tract Integrity On Upper Limb Motor Function In Stroke Patients Treated With Repetitive Transcranial Magnetic Stimulation

Objective: The incidence of residual upper limb motor dysfunction in stroke patients is high,which seriously affects the quality of life.Repetitive transcranial magnetic stimulation(r TMS),as a non-invasive nerve regulation technique,affects brain metabolism and nerve electrical activity through the principle of electromagnetic induction,and changes cortical plasticity,which is a new direction for the rehabilitation of upper limb motor function after stroke.As the bimodal balance recovery model,the retention of the corticospinal tract structure may influence the dominance of the interhemispheric competition model or the compensatory model in the theory of neurological function recovery after stroke.Therefore,this research is based on the bimodal balance recovery model to explore the effects of corticospinal tract integrity on upper limb motor function in stroke patients treated with repetitive transcranial magnetic stimulation and the neuroplasticity mechanism of motor function recovery in stroke patients to provide reference for transcranial magnetic stimulation therapy.Methods: Patients with upper limb motor dysfunction in the convalescent period of stroke in our hospital were selected as the research objects.Firstly,bilateral corticospinal tracts(CST)were reconstructed by diffusion tensor imaging(DTI).30 patients with high CST integrity(r FA > 0.5)and 30 patients with low CST integrity(r FA≤0.5)were selected respectively.The two groups were further subdivided into high frequency group(n=10),low frequency group(n=10)and control group(n=10)by random number table method,altogether 6 groups.All subjects were given routine medicine and conventional rehabilitation training intervention,mainly with neurodevelopmental protonation technology including Brunnstrom technology,Rood technology,Bobath technology,PNF technology and motor relearning technology.On this basis,Patients in the high frequency group were treated with 5Hz,90%RMT and18 min r TMS in the M1 region of the contralesional hemisphere for 3 weeks.The low-frequency group received 1Hz,90%RMT,18 min r TMS treatment in the contralesional hemisphere primary motor cortex for 3 weeks;The coil of the control group was 90° tilted,and the stimulation parameters were the same as those of the high frequency group.Fugl-meyer Rating Scale(FMA-UE),Wolf Motor Function Scale(WMFT)and Modified Barthel Index(MBI)were used to evaluate the efficacy of 6 groups before and 3 weeks after treatment respectively.Results: For high CST integrity group,after treatment,FMA-UE,WMFT and MBI scores of patients in high frequency group,low frequency group and control group were significantly improved compared with those before treatment(P < 0.05).FMA-UE,WMFT and MBI scores of low frequency group [38.10±5.71,43.20±5.32 and 78.00±11.35 points,respectively] were significantly better than those of high frequency group and control group(P < 0.05).No statistical significance was found between the high frequency group and the control group(P > 0.05).For low CST integrity group,after treatment,the scores of FMA-UE,WMFT and MBI in high frequency group were(12.00±1.40)points,(15.10±1.99)points and(49.00±5.68)points,respectively,compared with those before treatment(P < 0.05).For low CST integrity group,after treatment,the scores of FMA-UE,WMFT and MBI [(12.00±1.40)points,(15.10±1.99)points and(49.00±5.68)points,respectively]in high frequency group were significantly improved compared with those before treatment.MBI scores of patients in low-frequency group and control group[(45.00±5.72)points and(44.00±5.29)points,respectively] were better than before after treatment(P < 0.05),while FMA-UE and WMFT scores of patients in low-frequency group and control group were not significantly different before and after treatment(P > 0.05).Compared with the low frequency group and the control group,the improvement of various indicators in the high frequency group was more obvious(P < 0.05),while no statistical difference was found between the low frequency group and the control group(P > 0.05).Conclusions: For patients with high CST integrity,LF-r TMS over the contralesional cortex could be superior to HF-r TMS and control group in promoting upper limb motor function.For patients with low CST integrity,HF-r TMS over the contralesional cortex could have a better effect than LF-r TMS and sham stimulation on the improvement of upper limb motor function after stroke.