Transcranial magnetic stimulation and muscle contraction to enhance stroke recovery: a randomized 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 x 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.