Multifocal transcranial stimulation in chronic ischemic stroke: A phase 1/2a randomized trial

Abstract

Background and PurposeRepetitive transcranial magnetic stimulation (rTMS) may promote recovery of motor function after stroke by inducing functional reorganization of cortical circuits. The objective of this study was to examine whether multifocal cortical stimulation using a new wearable transcranial rotating permanent magnet stimulator (TRPMS) can promote recovery of motor function after stroke by inducing functional reorganization of cortical circuits. MethodsThirty30 patients with chronic ischemic stroke and stable unilateral weakness were enrolled in a Phase 1/2a randomized double-blind sham-controlled clinical trial to evaluate safety and preliminary efficacy. Bilateral hemispheric stimulation was administered for 20 sessions 40 min each over 4 weeks. The primary efficacy endpoint was the change in functional MRI BOLD activation immediately after end of treatment. Secondary efficacy endpoints were clinical scales of motor function, including the Fugl-Meyer motor arm score, ARAT, grip strength, pinch strength, gait velocity, and NIHSS. ResultsTRPMS treatment was well-tolerated with no device-related adverse effects. Active treatment produced a significantly greater increase in the number of active voxels on fMRI than sham treatment (median +48.5 vs -30, p = 0.038). The median active voxel number after active treatment was 8.8-fold greater than after sham (227.5 vs 26, p = 0.016). Although the statistical power was inadequate to establish clinical endpoint benefits, numerical improvements were demonstrated in 5 of 6 clinical scales of motor function. The treatment effects persisted over a 3-month duration of follow-up. ConclusionsMultifocal bilateral TRPMS was safe and showed significant fMRI changes suggestive of functional reorganization of cortical circuits in patients with chronic ischemic stroke. A larger randomized clinical trial is warranted to verify recovery of motor function.