Clinical application progress of transcranial magnetic stimulation in spasticity after stroke

Post-stroke spasticity(PSS) is one of the common manifestations of dyspraxia after stroke, with a high incidence. The main clinical manifestation is the enhancement of the muscle tension of the flexor group of the upper limb and the extensor group of the lower limb. The treatment of PSS includes drug therapy, manual stretching, nerve block therapy, etc. The treatment methods have their own advantages and disadvantages. Currently, there is no unified treatment for PSS, which is mainly based on comprehensive treatment. Transcranial magnetic therapy(TMS) is a non-invasive magnetic stimulation technique based on electromagnetic induction which change the cortical excitability. It has been widely used in nervous system diseases. TMS can be applied to the central nervous system and the peripheral nervous system. When applied to the central nervous system, treatment modes include low-frequency rTMS, high-frequency rTMS, and patterned TMS. In most studies, 1 Hz-rTMS was applied to the non-affected cerebral hemisphere. In a few studies, iTBS was applied to the affected cerebral hemisphere, and 10 Hz-rTMS was applied to the affected cerebral hemisphere. The application of high frequency rTMS and iTBS in the affected cerebral hemisphere can improve the cortical excitability, strengthen the control of the upper center on the spinal motor neurons, reduce the excitability and muscle spindle sensitivity of the motor neurons, and improve the symptoms of spasticity. Low-frequency rTMS are applied to the non-affected cerebral hemisphere to reduce the excitability of the non-affected cerebral hemisphere, reduce the inhibitory effect of the non-affected cerebral cortex on the affected cerebral cortex, restore the balance between the two hemispheres, and indirectly strengthen the control of the affected cerebral hemisphere on the spinal motor neurons. The current research applied to the periphery basically uses high-frequency rTMS treatment. The purpose of this review is to describe the clinical application progress of TMS in the treatment of spasticity after stroke.