Comparative efficacy of non-invasive neurostimulation therapies for poststroke dysphagia: A systematic review and meta-analysis

To explore the effect of non-invasive neurostimulation therapies on dysphagia patients after stroke.We searched MEDLINE (Ovid), PubMed, Embase, Web of Science, ScienceDirect, and Cochrane library databases until April 22, 2020. All published and unpublished randomized controlled trials (RCT) were included. Full texts were independently reviewed. The risk of RCT bias was evaluated by two independent assessors using the Cochrane risk of bias tool. The primary outcome measure was swallowing function before and after neurostimulation therapy. The effect sizes are calculated from the extracted data and combined into a comprehensive summary statistic.A total of 27 randomized controlled trials were included in this study, involving 914 stroke patients (27 intervention groups and 20 control groups). Meta-analysis showed that compared with the control group, noninvasive neurostimulation therapies (repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), surface neuromuscular electrical stimulation (sNMES) or pharyngeal electrical stimulation (PES)) had a better effect (SMD = 0.91; 95% CI: 0.54-1.27; Z = 4.84; P < 0.00001; I² = 86%). In the subgroup analysis based on type of stimulus, rTMS appeared to perform better. In the subgroup analysis based on clinical phase, stimulation applied in the acute phase may be more effective. In the subgroup analysis based on the site of injury, the brainstem injury group seemed to achieve better outcomes. In the subgroup analysis based on stroke type, the cerebral infarction group had better outcomes than the cerebral infarction/hemorrhage mixed group.Non-invasive neurostimulation therapies can effectively promote the recovery of dysphagia after stroke.