Contralesional plantar peripheral electrical stimulation combined with contralesional posterior parietal cortex repetitive transcranial magnetic stimulation promotes lower-limb motor recovery in stroke patients with hemiparesis: a randomized, double-blind, factorial controlled trial

To examine the effects and interaction of contralesional plantar peripheral electrical stimulation (PES) and posterior parietal cortex transcranial magnetic stimulation (PPC-TMS) on lower-limb motor function, balance, activities of daily living, and gait variables in patients with subacute post-stroke hemiparesis. This study used a prospective, randomized, double-blind 2 × 2 factorial trial design. A total of 151 patients with post-stroke hemiparesis (2 weeks to 6 months after onset) were enrolled and randomly assigned (1:1:1:1) to a double-sham control group, real PES group, real PPC-TMS group, or combined intervention group. All groups received the assigned intervention in addition to conventional rehabilitation: real PES was delivered to the plantar surface of the contralesional, non-paretic foot (i.e., the foot opposite to the paretic lower limb); real PPC-TMS targeted the contralesional posterior parietal cortex using an intermittent theta-burst stimulation (iTBS) protocol, 5 sessions/week for 4 weeks. The primary outcome was the post-intervention Fugl–Meyer Assessment for the Lower Extremity (FMA-LE) score (analyzed using a 2 × 2 factorial model with baseline FMA-LE as a covariate). Secondary outcomes included the Postural Assessment Scale for Stroke Patients (PASS), Berg Balance Scale (BBS), lower-limb–related Modified Barthel Index (MBI), and three-dimensional gait parameters. Baseline characteristics were comparable among the four groups. After the intervention, FMA-LE scores were 19.40 ± 3.21, 21.00 ± 3.10, 21.12 ± 3.16, and 25.60 ± 2.80, respectively. Compared with the control group, the real PES group, real PPC-TMS group, and combined group showed higher post-intervention FMA-LE scores by 1.60, 1.70, and 6.20 points, respectively (all P < 0.05). In the baseline-adjusted factorial model, the PES×PPC-TMS interaction was significant ( P = 0.004). Regarding secondary outcomes, PASS, BBS, and lower-limb MBI improved versus control, with the combined group demonstrating the greatest overall gains. Three-dimensional gait analysis showed improvements in parameters including hip flexion, knee flexion, pelvic angles, and ankle joint angles, with evidence of interaction effects. Contralesional plantar PES combined with contralesional PPC-TMS significantly enhances lower-limb motor recovery of the affected side in patients with subacute post-stroke hemiparesis. The combined intervention exhibits synergistic benefits, providing preliminary clinical evidence supporting a “contralesional dual-pathway” stimulation strategy.