Transcranial magnetic stimulation and muscle contraction to enhance stroke recovery: A randomised proof-of-principle and feasibility investigation

Objective. To explore the efficacy of repetitive transcranial magnetic stimulation (rTMS) and voluntary muscle contraction (VMC) to improve corticospinal transmission, muscle function, and purposeful movement early after stroke. Methods. Factorial 2 × 2 randomized single-blind trial. Subjects: n = 27, mean age 75 years, mean 27 days after middle cerebral artery infarct (24 subjects completed outcome measures). Procedure: after baseline measurement (day 1), subjects were randomized to 1 of 4 groups. Treatment was given for the next 8 working days, and outcome was measured on day 10. Interventions: (a) Real-rTMS + RealVMC, (b) Real-rTMS + PlaceboVMC, (c) Placebo-rTMS + RealVMC, and (d) Placebo-rTMS + PlaceboVMC. Real-rTMS consisted of 200 1-Hz stimuli at 120% motor threshold in 5 blocks of 40 separated by 3 minutes delivered to the lesioned hemisphere. Placebo-rTMS used a dummy coil. In RealVMC, the paretic elbow was repeatedly flexed/extended for 5 minutes. In PlaceboVMC, subjects viewed pairs of drawings of upper limbs and reported their likeness. Outcomes: frequency of motor-evoked potentials in biceps and triceps, muscle function (torque about elbow), and purposeful movement (Action Research Arm Test). Analysis: group mean changes (outcome — baseline) were compared. Results. In the Real-rTMS + RealVMC group, motor-evoked potential frequency increased 14% for biceps and 20% for triceps, whereas in the Placebo-rTMS + PlaceboVMC group, it decreased 12% for biceps and 6% for triceps. For other groups, there were changes of intermediate values. No meaningful differences were found for secondary outcomes. Conclusions . A positive trend for motor-evoked potential frequency was found for Real-rTMS + RealVMC, whereas a negative trend for motor-evoked potential frequency was found for Placebo-rTMS + PlaceboVMC.