Effects of repetitive transcranial magnetic stimulation on recovery in lower limb muscle strength and gait function following spinal cord injury: a randomized controlled trial

STUDY DESIGN: Randomized sham-controlled clinical trial. OBJECTIVES: The objective of this study is to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) compared to sham stimulation, on the development of lower limb muscle strength and gait function during rehabilitation of spinal cord injury (SCI). SETTING: SCI rehabilitation hospital in Viborg, Denmark. METHODS: Twenty individuals with SCI were randomized to receive rTMS (REAL, n = 11) or sham stimulation (SHAM, n = 9) and usual care for 4 weeks. rTMS (20 Hz, 1800 pulses per session) or sham stimulation was delivered over leg M1 Monday–Friday before lower limb resistance training or physical therapy. Lower limb maximal muscle strength (MVC) and gait function were assessed pre- and post intervention. Lower extremity motor score (LEMS) was assessed at admission and at discharge. RESULTS: One individual dropped out due to seizure. More prominent increases in total leg (effect size (ES): 0.40), knee flexor (ES: 0.29), and knee extensor MVC (ES: 0.34) were observed in REAL compared to SHAM; however, repeated-measures ANOVA revealed no clear main effects for any outcome measure (treatment p > 0.15, treatment × time p > 0.76, time p > 0.23). LEMS improved significantly for REAL at discharge, but not for SHAM, and REAL demonstrated greater improvement in LEMS than SHAM (p < 0.02). Similar improvements in gait performance were observed between groups. CONCLUSIONS: High-frequency rTMS may increase long-term training-induced recovery of lower limb muscle strength following SCI. The effect on short-term recovery is unclear. Four weeks of rTMS, when delivered in conjunction with resistance training, has no effect on recovery of gait function, indicating a task-specific training effect.