Effects of repetitive transcranial magnetic stimulation on contralesional dorsal premotor cortex in subcortical stroke patients with moderate to severe upper limb motor impairment: a pilot randomized controlled trial

ObjectiveThis randomized controlled study examines the effect of repetitive transcranial magnetic stimulation on contralesional dorsal premotor cortex in patients in the subaucte phase of stroke recovery. MethodsThis randomized controlled study includes three groups: contralesional dorsal premotor cortex(cPMd), contralesional primary motor cortex(cM1) and sham stimulation. 60 Participants were divided into 3 groups according to random block method. They all received a 3-week intervention. The primary outcome was using the Fugl Meyer Assessment (FMA) to evaluate the motor function of the affected limb. The secondary outcomes included: Brunnstrom hemiplegia grading, Action Research Arm Test (ARAT), Wolf Motor Function Test (WMFT), Barthel Index (BI), electrophysiological assessment (bilateral hemisphere MEP, ipsilesional central conduction time, ipsilesional latency). ResultsComparative analysis revealed that the cPMd group demonstrated significant improvements in both the Fugl-Meyer Assessment for Upper Extremity (FMA-UE) and distal upper limb scores relative to the cM1 group (P<0.05) and the sham group (P<0.001). Whats more, the cPMd group exhibited marked enhancementsin FMA for Lower Extremity (FMA-LE), proximal upper limb, and hand scores (P[&le;]0.01) compared to the sham stimulation group. However, the study revealed limited improvements in electrophysiological assessments, with only ipsilesional central conduction time showing significant changes compared to the sham group. DiscussionThis study provides some evidence for the effect of high-frequency rTMS stimulation in the cPMd on improving stroke motor disorders. The cPMd group showed significant improvement in FMA-UE scores compared to the cM1 group. It suggests that high-frequency rTMS in the cPMd may be a unique and more effective strategy for optimizing brain motor networks and improving patient dysfunction. This provides new ideas for TMS assessment and intervention of brain areas based on complex brain networks and proposes new possible treatment strategies. In the future, a multi-center, large-scale systematic study is needed to explore the use of high-frequency rTMS in the cPMd for stroke hemiplegia recovery, and to further investigate the pathophysiological mechanisms of disease recovery, as well as to explore the neural plasticity mechanism of stroke motor dysfunction recovery. Therefore, the rehabilitation potential of high-frequency rTMS in the cPMd still needs further exploration and better promotion of motor function recovery in stroke patients.