Clinical efficacy evaluation of combined central and peripheral repetitive transcranial magnetic stimulation for elbow flexor (biceps Brachii) spasticity and upper limb motor function after stroke

Abstract

Objective This randomized controlled trial aimed to evaluate the efficacy and temporal dynamics of a combined central and peripheral magnetic stimulation protocol, combining central (M1) and peripheral (Erb’s point) stimulation with conventional rehabilitation, for post-stroke elbow flexor spasticity and motor function. Methods One hundred eligible stroke patients with upper limb spasticity were randomly allocated to Group A (n = 50) or Group B (n = 50). In a 6-week delayed-start design, Group A received active combined central and peripheral magnetic stimulation during weeks 1–3, while Group B received it during weeks 4–6. Both groups received concurrent conventional rehabilitation throughout. Primary outcomes included the Modified Ashworth Scale (MAS) for spasticity and the Fugl-Meyer Assessment for Upper Extremity (FMA-UE) for motor function. Secondary neurophysiological outcomes comprised motor evoked potential (MEP) amplitude and the root mean square (RMS) of biceps brachii electromyography. Assessments were performed at baseline, after 3-weeks and 6 weeks. Results A clear phase-specific effect was observed. At 3 weeks, Group A demonstrated significantly greater reduction in MAS scores (2(2, 3) vs. 3(2, 3), p < 0.001) and greater improvement in FMA-UE scores (22.2 ± 5.63 vs. 19.2 ± 5.53, p = 0.010) compared to Group B. Neurophysiologically, Group A showed an earlier reduction in RMS (20.14 ± 6.71 μV vs. 27.48 ± 7.29 μV, p < 0.001) and a transient decrease in contralesional MEP amplitude at 3 weeks. These intergroup differences narrowed at 6 weeks after Group B received the delayed intervention, suggesting that delayed active stimulation may also confer benefit, although spontaneous recovery and concurrent rehabilitation may have contributed to this convergence. Furthermore, the MEP elicitation rate in the affected hemisphere increased more substantially after combined central and peripheral magnetic stimulation treatment, suggesting a significant enhancement of cortical excitability in the affected hemisphere. Conclusion A combined central and peripheral rTMS protocol integrated with conventional rehabilitation is effective in alleviating elbow flexor spasticity and improving motor function after stroke. The delayed-start design supports that the observed benefits are attributable to the rTMS intervention, although residual placebo effects cannot be fully excluded. The effects are phase-specific, with motor improvement maintained at 6 weeks and a complex temporal pattern of spasticity reduction, likely mediated by modulating cortical excitability and spinal motor neuron pool activity.