Dual-mode noninvasive brain stimulation over the bilateral primary motor cortices in stroke patients

Background: Noninvasive brain stimulation (NBS) using repetitive transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS) has recently been adopted for modulating motor function in stroke patients. Objective: We investigated the effect of simultaneous dual-mode sti mulation using rTMS and tDCS over the bilateral primary motor cortices (M1) to assess its efficacy as compared to single stimulation using rTMS for the recovery of motor function in subacute stroke patients. Methods: Thirty subacute stroke patients were recruited in this study. In the dual-mode stimulation group, 10 Hz rTMS (90% of resting motor threshold, 1,000 pulses) was applied over the ipsilesional M1 for 20 minutes with the simultaneous application of cathodal tDCS (2 mA) on the contralesional M1. The single stimulation group underwent 10 Hz rTMS without tDCS. Ten daily sessions were conducted for two consecutive weeks. The total Fugl-Meyer (FMA-T), upper limb (FMA-UL), and lower limb (FMA-LL) scores were measured before, after, and two months later. Results: The FMA-T and FMA- UL were significantly improved over time in both the dual and single stimulation group (p < 0.05). However, there were significant group and time interaction effects in both the FMA-T and FMA-UL (p < 0.05). Post-hoc analysis showed that the mean changes in the FMA-T and FMA-UL were significantly better in the dual-mode stimulation group. Conclusion: Dual-mode NBS with the simultaneous application of 10 Hz rTMS and cathodal tDCS over the bilateral M1s was safe and superior to 10 Hz rTMS alone for improving motor function in subacute stroke patients.