Improvement of dexterity by single session low-frequency repetitive transcranial magnetic stimulation over the contralesional motor cortex in acute stroke: A double-blind placebo-controlled crossover trial

PURPOSE: Increasing evidence suggests that the contralesional motor cortex (M1) inhibits the ipsilesional M1 in stroke patients. This inhibition could impair motor function of the affected hand. We investigated if inhibitory 1~Hz repetitive transcranial magnetic stimulation (rTMS) over the contralesional M1 improved motor performance of the affected hand in acute stroke. METHODS: A double-blind study of real versus placebo rTMS was conducted. Twelve patients early after subcortical stroke (mean: 7 days) received 1200 stimuli of real and placebo rTMS in a crossover design. The sequence of stimulations was counterbalanced across subjects. Stimulus intensity was subthreshold (90% of motor threshold at rest). Motor function was tested by grip strength recordings and Nine Hole Peg Test (NHPT) executions before and after each rTMS session. RESULTS: Compared to sham stimulation, real rTMS improved NHPT results but not grip strength in the affected hand. No change of performance was observed for the unaffected hand. NHPT baseline repetitions in a subgroup of patients indicated stable motor performance prior to the rTMS sessions. CONCLUSIONS: The study suggests that therapeutic rTMS applications over the contralesional hemisphere are feasible in acute stroke patients and can transiently improve dexterity of the affected hand. RTMS may become an additional tool for early neurorehabilitation.