Short-term Effect of Noninvasive Brain Stimulation Techniques on Motor Impairment in Chronic Ischemic Stroke: A Systematic Review with Meta-Analysis

In recent years, noninvasive brain stimulation (NIBS) has shown promise for stroke rehabilitation as a novel nonpharmaceutical neuromodulatory intervention with attractive neurophysiological theories backing it up.To find out the short-term effects of NIBS techniques on motor impairment in chronic ischemic stroke.A systematic review with meta-analysis was performed separately for transcranial direct current stimulation (tDCS), transcranial magnetic stimulation (TMS), and studies that combined both, utilizing various databases for a period spanning from 2001 to 2019. Good-quality randomized controlled trials (RCTs) on chronic ischemic stroke cases with homogeneous clinical upper motor short-term outcome measures were considered for the meta-analysis. RevMan 5.1 software was used for the meta-analysis. Meta-analysis registration: CRD42021196299; https://www.crd.york.ac.uk/PROSPERO.A total of 319 studies were identified initially. After necessary filters to comply with the strict recruitment criteria, only four studies qualified, two each for tDCS and TMS and none qualified for analysis under the combined category. tDCS showed a nonsignificant effect on the upper limb motor function improvement (-0.10 [95% confidence interval {CI}: -0.84 to 0.64; I2 0%; P = 0.8]), whereas the repetitive TMS showed a significant effect (0.75 [95% CI: 0.03-1.48; I2 0%; P = 0.04]). The safety analysis did not reveal any major concerns for several published protocols.tDCS alone did not significantly benefit motor recovery; rTMS was effective in providing immediate functional benefits in chronic ischemic stroke. While the current stroke rehabilitation protocols with NIBS appear safe, more good-quality stratified RCTs with more innovative experimental protocols are needed to analyze and quantify the efficacy of these techniques in stroke rehabilitation.