Effects of Theta Burst Peripheral Magnetic Stimulation on Cortical Excitability and Upper Limb Function After Stroke: Protocol for a Randomized Controlled Trial

Xiaoying Lin¹Ketao Du¹Rongqi Ding²Qiuyu Chen³Xiaomin Niu¹Qinjie Yang⁴Chunyang Liao⁵Tiantian Xin¹Shuqin Li¹Xiaying Fu^1*Jianghua Cheng^1*

• ¹South China Hospital of Shenzhen University, Shenzhen, China
• ²Jilin Medical University, Jilin, China
• ³Yunnan University Of Bussiness Management, Yunnan, China
• ⁴Dongguan Huangjiang Hospital , Department of Rehabilitation Medicine, Dongguan, China
• ⁵South China Hospital Affiliated to Shenzhen University, Shenzhen, China

Introduction: Post-stroke spasticity affects 25–40% of survivors, causing pain and functional impairment. Current non-invasive treatments target either central or peripheral pathways alone. This neglects the critical imbalance between spastic agonists and antagonists. We designed this protocol to address this gap through dual-site peripheral theta-burst stimulation. Methods: This single-center, three-arm, sham-controlled, single-blind randomized controlled trial enrolled 54 stroke survivors (aged 40–80, 3–12 months post-stroke, Modified Ashworth Scale score ≥ 1). Participants were randomized in a 1:1:1 ratio to receive a 10-session intervention over two weeks (5 days/week). Each session consisted of stimulation followed by 30 minutes of conventional physical therapy. The stimulation protocols were: Group 1: active iTBS over extensor carpi radialis longus + sham cTBS over flexor carpi radialis; Group 2: sham iTBS + active cTBS; Group 3: active iTBS + active cTBS. Stimulation was delivered using a MagTD stimulator at 110–120% of the peripheral motor threshold (mean 38.4% maximum stimulator output), with 600 pulses per session (50 Hz burst frequency, 5 Hz theta rhythm). Anticipated Results: We hypothesize that Group 3 (combined stimulation) will yield the greatest reduction in spasticity (MAS decrease ≥1) and the most significant improvements in upper-limb function (FMA-UE, ARAT) compared to Groups 1 and 2. These clinical gains are expected to correlate with neurophysiological changes (MEP amplitude, cortical silent period), supporting the central-peripheral synergy model. This is a provisional file, not the final typeset article Discussion: This protocol tests a novel dual-site pTBS paradigm. Positive findings would provide preliminary evidence for network-based rehabilitation. This could inform larger trials and potentially transform post-stroke spasticity management.